Pub Date : 2024-08-27DOI: 10.1128/spectrum.04188-23
Qasim Ali, Sen Ma, Umar Farooq, Boshuai Liu, Zhichang Wang, Hao Sun, Yalei Cui, Defeng Li, Yinghua Shi
It is commonly accepted that dietary fibers are good for gut health. The effect of fibers on the diversity and metabolic activities of the cecal microflora, however, differ with the passage of time. Therefore, we investigated the time-series impacts of the pasture grazing system (a high dietary fiber source) on the cecal microbiome and short-chain fatty acids in Wanpu geese, comparing it to commercial feeding (a low dietary fiber source). The cecal microbiota composition and SCFA concentrations were evaluated by 16S rRNA gene sequencing and gas chromatography, respectively. We found that pasture produced a generally quick positive response to Bacteroidales, Lactobacillales, Gastranaerophilales (at 45 days), Lachnospirales, and Oscillospirales (at 60 days and 90 days) irrespective of Erysipelotrichales (at 45 days), Clostridia_UCG-014, RF39 (at 60 days), Christensenellales, and Peptostreptococcales-Tissierellales (at 90 days) in geese. Meanwhile, we found that Lactobacillales, Gastranaerophilales, Lachnospirales, and Oscillospirales were significantly correlated with short-chain fatty acids in pasture grazing geese. Indeed, the correlation of cecal microbiota with SCFAs led to altered microbial functions evinced by COG; KEGG pathway levels 1, 2, and 3; BugBase; and FAPROTAX databases. This study emphasizes the importance of dietary fiber sources in influencing beneficial impacts in regulating geese microbiota homeostasis and metabolic functions such as energy and lipid metabolism.IMPORTANCELow dietary fiber diet sources cause gut microbial and short-chain fatty acid alterations that lead to compromised animal health. The establishment of an artificial pasture grazing system at the expense of ryegrass is a good source of dietary fiber for geese. Our results described the importance of pasture in maintaining the gut microbiota, SCFAs, and potential microbial functions reported by COG; KEGG pathway levels 1, 2, and 3; BugBase; and FAPROTAX databases.
{"title":"Chronological dynamics of the gut microbiome in response to the pasture grazing system in geese.","authors":"Qasim Ali, Sen Ma, Umar Farooq, Boshuai Liu, Zhichang Wang, Hao Sun, Yalei Cui, Defeng Li, Yinghua Shi","doi":"10.1128/spectrum.04188-23","DOIUrl":"https://doi.org/10.1128/spectrum.04188-23","url":null,"abstract":"<p><p>It is commonly accepted that dietary fibers are good for gut health. The effect of fibers on the diversity and metabolic activities of the cecal microflora, however, differ with the passage of time. Therefore, we investigated the time-series impacts of the pasture grazing system (a high dietary fiber source) on the cecal microbiome and short-chain fatty acids in Wanpu geese, comparing it to commercial feeding (a low dietary fiber source). The cecal microbiota composition and SCFA concentrations were evaluated by 16S rRNA gene sequencing and gas chromatography, respectively. We found that pasture produced a generally quick positive response to Bacteroidales, Lactobacillales, Gastranaerophilales (at 45 days), Lachnospirales, and Oscillospirales (at 60 days and 90 days) irrespective of Erysipelotrichales (at 45 days), <i>Clostridia_UCG-014</i>, <i>RF39</i> (at 60 days), Christensenellales, and Peptostreptococcales-Tissierellales (at 90 days) in geese. Meanwhile, we found that Lactobacillales, Gastranaerophilales, Lachnospirales, and Oscillospirales were significantly correlated with short-chain fatty acids in pasture grazing geese. Indeed, the correlation of cecal microbiota with SCFAs led to altered microbial functions evinced by COG; KEGG pathway levels 1, 2, and 3; BugBase; and FAPROTAX databases. This study emphasizes the importance of dietary fiber sources in influencing beneficial impacts in regulating geese microbiota homeostasis and metabolic functions such as energy and lipid metabolism.IMPORTANCELow dietary fiber diet sources cause gut microbial and short-chain fatty acid alterations that lead to compromised animal health. The establishment of an artificial pasture grazing system at the expense of ryegrass is a good source of dietary fiber for geese. Our results described the importance of pasture in maintaining the gut microbiota, SCFAs, and potential microbial functions reported by COG; KEGG pathway levels 1, 2, and 3; BugBase; and FAPROTAX databases.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.01227-24
Maximilian Hanusch, Xie He, Laura Böll, Robert R Junker
Dispersal, environmental filtering, and biotic interactions define the species inventory of local communities. Along successional gradients, these assembly processes are predicted to sequentially vary in their relative importance with dispersal as the dominating process early in succession, followed by environmental filtering and biotic interactions at later stages. While observational data from field studies supported this prediction, controlled experiments confirming a sequence of successional processes are still lacking. We designed miniature ecosystems to explicitly test these assumptions under controlled laboratory conditions. Our "Ecosystems on a Plate" (EsoaP) are 3D-printed customized microplates with 24 connected wells allowing us to track dispersal, niche filtering, and biotic interactions among bacteria and plants in time and space. Within EsoaPs, we created heterogeneous habitat landscapes by well-specific nutrient levels or by providing plant seedlings as mutualistic partners in a checkerboard pattern. Bacteria of a single strain were released in one well and subsequently distributed themselves within the plates. We measured the spatial distribution of bacterial abundances at two time points as a function of abiotic or biotic heterogeneity. Bacterial abundance distribution confirmed a shift from initial dispersal-dominated processes to later niche filtering and biotic interactions as more important processes. Our approach follows the principles of open science as the affordable availability of 3D printers as well as shared STL files makes EsoaPs disseminatable and accessible to all levels of society, facilitating future experimental research.
Importance: Hypotheses regarding the underlying processes of ecological successions have primarily emerged from and have been tested in observational studies, lacking substantial support through controlled experiments. The design of such experiments should focus on testing contemporary ecological theories at the intersection of community assembly and successional research. To achieve this, we developed and employed 3D-printed "Ecosystems on a Plate" (EsoaP) within controlled laboratory settings. EsoaPs surmount several limitations of nanoscale instruments that had hindered their application in ecologically meaningful research. By sharing 3D printing designs, experimental protocols, and data openly, we facilitate reproducibility of our experiments by researchers across diverse ecological disciplines. Moreover, our approach facilitates cost-effective replication of experiments, democratizing access to tools for ecological research, and thus holds the potential to serve as a model for future studies and educational purposes.
{"title":"Testing the sequence of successional processes in miniature ecosystems.","authors":"Maximilian Hanusch, Xie He, Laura Böll, Robert R Junker","doi":"10.1128/spectrum.01227-24","DOIUrl":"https://doi.org/10.1128/spectrum.01227-24","url":null,"abstract":"<p><p>Dispersal, environmental filtering, and biotic interactions define the species inventory of local communities. Along successional gradients, these assembly processes are predicted to sequentially vary in their relative importance with dispersal as the dominating process early in succession, followed by environmental filtering and biotic interactions at later stages. While observational data from field studies supported this prediction, controlled experiments confirming a sequence of successional processes are still lacking. We designed miniature ecosystems to explicitly test these assumptions under controlled laboratory conditions. Our \"Ecosystems on a Plate\" (EsoaP) are 3D-printed customized microplates with 24 connected wells allowing us to track dispersal, niche filtering, and biotic interactions among bacteria and plants in time and space. Within EsoaPs, we created heterogeneous habitat landscapes by well-specific nutrient levels or by providing plant seedlings as mutualistic partners in a checkerboard pattern. Bacteria of a single strain were released in one well and subsequently distributed themselves within the plates. We measured the spatial distribution of bacterial abundances at two time points as a function of abiotic or biotic heterogeneity. Bacterial abundance distribution confirmed a shift from initial dispersal-dominated processes to later niche filtering and biotic interactions as more important processes. Our approach follows the principles of <i>open science</i> as the affordable availability of 3D printers as well as shared STL files makes EsoaPs disseminatable and accessible to all levels of society, facilitating future experimental research.</p><p><strong>Importance: </strong>Hypotheses regarding the underlying processes of ecological successions have primarily emerged from and have been tested in observational studies, lacking substantial support through controlled experiments. The design of such experiments should focus on testing contemporary ecological theories at the intersection of community assembly and successional research. To achieve this, we developed and employed 3D-printed \"Ecosystems on a Plate\" (EsoaP) within controlled laboratory settings. EsoaPs surmount several limitations of nanoscale instruments that had hindered their application in ecologically meaningful research. By sharing 3D printing designs, experimental protocols, and data openly, we facilitate reproducibility of our experiments by researchers across diverse ecological disciplines. Moreover, our approach facilitates cost-effective replication of experiments, democratizing access to tools for ecological research, and thus holds the potential to serve as a model for future studies and educational purposes.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142080883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.01173-24
Jesus G M Pariona, Felipe Vásquez-Ponce, Johana Becerra, Thais Martins-Gonçalves, Eva M M Pariona, Fabio T Madueño, Fernanda Esposito, Aline V de Lima, Jorge L Mello Sampaio, Rodrigo S Galhardo, Nilton Lincopan
Klebsiella pneumoniae strains that produce Klebsiella pneumoniae Carbapenemase (KPC) variants displaying resistance to ceftazidime-avibactam (CZA) often remain susceptible to meropenem (MEM), suggesting a potential therapeutic use of this carbapenem antibiotic. However, in vitro studies indicate that these sorts of strains can mutate becoming MEM-resistant, raising concerns about the effectiveness of carbapenems as treatment option. We have studied mutation rates occurring from the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae belonging to ST11. Two-step fluctuation assays (FAs) were conducted. In brief, initial cultures of KPC-114-producing K. pneumoniae showing 1 µg/mL MEM MIC were spread on Mueller-Hinton agar plates containing 2-8 µg/mL MEM. A second step of FA, at 4-16 µg/mL MEM was performed from a mutant colony obtained at 2 µg/mL MEM. Mutation rates were calculated using maximum likelihood estimation. Parental and mutant strains were sequenced by Illumina NextSeq, and mutations were predicted by variant-calling analysis. At 8 µg/mL MEM, mutants derived from parental CZA-resistant (MIC ≥ 64 µg/mL)/MEM-susceptible (MIC = 1 µg/mL) KPC-114-positive K. pneumoniae exhibited an accumulative mutation rate of 3.05 × 10-19 mutations/cell/generation, whereas at 16 µg/mL MEM an accumulative mutation rate of 1.33 × 10-19 mutations/cell/generation resulted in the reversion of KPC-114 (S181_P182 deletion) to KPC-2. These findings highlight that the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae ST11 is related to low mutation rates suggesting a low risk of therapeutic failure. In vivo investigations are necessary to confirm the clinical potential of MEM against CZA-resistant KPC variants.IMPORTANCEThe emergence of ceftazidime-avibactam (CZA) resistance among carbapenem-resistant Klebsiella pneumoniae is a major concern due to the limited therapeutic options. Strikingly, KPC mutations mediating CZA resistance are generally associated with meropenem susceptibility, suggesting a potential therapeutic use of this carbapenem antibiotic. However, the reversion of meropenem-susceptible to meropenem-resistant could be expected. Therefore, knowing the mutation rate related to this genetic event is essential to estimate the potential use of meropenem against CZA-resistant KPC-producing K. pneumoniae. In this study, we demonstrate, in vitro, that under high concentrations of meropenem, reversion of KPC-114 to KPC-2 in CZA-resistant/meropenem-susceptible K. pneumoniae belonging to the global high-risk ST11 is related to low mutation rates.
产生肺炎克雷伯氏菌碳青霉烯酶(KPC)变体的肺炎克雷伯氏菌菌株对头孢他啶-阿维巴坦(CZA)具有耐药性,但往往对美罗培南(MEM)仍然敏感,这表明这种碳青霉烯类抗生素具有潜在的治疗用途。然而,体外研究表明,这类菌株会发生变异,对美罗培南产生耐药性,从而引发了人们对碳青霉烯类抗生素治疗效果的担忧。我们研究了 ST11 型耐 CZA 肺炎双球菌从对 MEM 敏感的 KPC-114 转为对 MEM 敏感的 KPC-2 过程中发生的变异率。我们进行了两步波动试验(FA)。简言之,将 MEM MIC 值为 1 µg/mL 的 KPC-114 产菌肺炎克雷伯菌的初始培养物涂在含有 2-8 µg/mL MEM 的 Mueller-Hinton 琼脂平板上。从在 2 µg/mL MEM 下获得的突变菌落开始,在 4-16 µg/mL MEM 下进行第二步 FA。突变率采用最大似然估计法计算。亲本和突变菌株由 Illumina NextSeq 测序,突变由变异调用分析预测。在 8 微克/毫升 MEM 的条件下,亲本对 CZA 耐药(MIC ≥ 64 微克/毫升)/对 MEM 易感(MIC = 1 微克/毫升)的 KPC-114 阳性肺炎双球菌产生的突变体的累积突变率为 3.05 × 10-19 突变/细胞/代,而在 16 µg/mL MEM 下,1.33 × 10-19 突变/细胞/代的累积突变率导致 KPC-114 (S181_P182 缺失)逆转为 KPC-2。这些发现突出表明,在耐 CZA 的肺炎双球菌 ST11 中,MEM 易感的 KPC-114 可逆转为 MEM 耐药的 KPC-2,这与低突变率有关,表明治疗失败的风险很低。重要意义由于治疗方案有限,耐碳青霉烯类肺炎克雷伯菌对头孢他啶-阿维巴坦(CZA)产生耐药性是一个值得关注的重大问题。引人注目的是,介导 CZA 耐药性的 KPC 突变通常与美罗培南的敏感性相关,这表明这种碳青霉烯类抗生素具有潜在的治疗用途。不过,预计美罗培南敏感性会逆转为美罗培南耐药性。因此,了解与这一基因事件相关的突变率对于估计美罗培南在抗产CZA耐药KPC肺炎克菌方面的潜在用途至关重要。在本研究中,我们在体外证明了在高浓度美罗培南的作用下,属于全球高风险 ST11 的耐 CZA/对美罗培南敏感的肺炎双球菌的 KPC-114 向 KPC-2 的逆转与低突变率有关。
{"title":"Reversion of KPC-114 to KPC-2 in ceftazidime-avibactam- resistant/meropenem-susceptible <i>Klebsiella pneumoniae</i> ST11 is related to low mutation rates.","authors":"Jesus G M Pariona, Felipe Vásquez-Ponce, Johana Becerra, Thais Martins-Gonçalves, Eva M M Pariona, Fabio T Madueño, Fernanda Esposito, Aline V de Lima, Jorge L Mello Sampaio, Rodrigo S Galhardo, Nilton Lincopan","doi":"10.1128/spectrum.01173-24","DOIUrl":"10.1128/spectrum.01173-24","url":null,"abstract":"<p><p><i>Klebsiella pneumoniae</i> strains that produce <i>Klebsiella pneumoniae</i> Carbapenemase (KPC) variants displaying resistance to ceftazidime-avibactam (CZA) often remain susceptible to meropenem (MEM), suggesting a potential therapeutic use of this carbapenem antibiotic. However, <i>in vitro</i> studies indicate that these sorts of strains can mutate becoming MEM-resistant, raising concerns about the effectiveness of carbapenems as treatment option. We have studied mutation rates occurring from the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant <i>K. pneumoniae</i> belonging to ST11. Two-step fluctuation assays (FAs) were conducted. In brief, initial cultures of KPC-114-producing <i>K. pneumoniae</i> showing 1 µg/mL MEM MIC were spread on Mueller-Hinton agar plates containing 2-8 µg/mL MEM. A second step of FA, at 4-16 µg/mL MEM was performed from a mutant colony obtained at 2 µg/mL MEM. Mutation rates were calculated using maximum likelihood estimation. Parental and mutant strains were sequenced by Illumina NextSeq, and mutations were predicted by variant-calling analysis. At 8 µg/mL MEM, mutants derived from parental CZA-resistant (MIC ≥ 64 µg/mL)/MEM-susceptible (MIC = 1 µg/mL) KPC-114-positive <i>K. pneumoniae</i> exhibited an accumulative mutation rate of 3.05 × 10<sup>-19</sup> mutations/cell/generation, whereas at 16 µg/mL MEM an accumulative mutation rate of 1.33 × 10<sup>-19</sup> mutations/cell/generation resulted in the reversion of KPC-114 (S181_P182 deletion) to KPC-2. These findings highlight that the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant <i>K. pneumoniae</i> ST11 is related to low mutation rates suggesting a low risk of therapeutic failure. <i>In vivo</i> investigations are necessary to confirm the clinical potential of MEM against CZA-resistant KPC variants.IMPORTANCEThe emergence of ceftazidime-avibactam (CZA) resistance among carbapenem-resistant <i>Klebsiella pneumoniae</i> is a major concern due to the limited therapeutic options. Strikingly, KPC mutations mediating CZA resistance are generally associated with meropenem susceptibility, suggesting a potential therapeutic use of this carbapenem antibiotic. However, the reversion of meropenem-susceptible to meropenem-resistant could be expected. Therefore, knowing the mutation rate related to this genetic event is essential to estimate the potential use of meropenem against CZA-resistant KPC-producing <i>K. pneumoniae</i>. In this study, we demonstrate, <i>in vitro</i>, that under high concentrations of meropenem, reversion of KPC-114 to KPC-2 in CZA-resistant/meropenem-susceptible <i>K. pneumoniae</i> belonging to the global high-risk ST11 is related to low mutation rates.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142080846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.04051-23
Angeliki Angelopoulou, Hugh M B Harris, Alicja K Warda, Carol-Anne O'Shea, Aonghus Lavelle, C Anthony Ryan, Eugene Dempsey, Catherine Stanton, Colin Hill, R Paul Ross
Subclinical mastitis is an asymptomatic inflammatory condition that can be difficult to define and diagnose. In the dairy industry, subclinical mastitis is diagnosed by milk somatic cell counts (SCCs) of ≥250,000 cells mL-1. In this pilot study, we assessed the efficacy of this index to identify human subclinical mastitis by comparing SCC levels with the inflammatory response [interleukin-8 (IL-8) levels] in 37 samples from asymptomatic and 10 clinical mastitis (CM) lactating women. The milk microbiota was determined by 16S rRNA gene sequencing. The SCC of CM samples ranged from 310,000 to 6,600,000 cells mL-1. However, 14 of 37 (37.8%) asymptomatic samples had high SCC (250,000-460,000 cells mL-1), indicating subclinical mastitis. SCC levels significantly (P < 0.001) and positively correlated with milk IL-8 levels reflecting the escalating inflammatory response across subclinical and clinical mastitis samples. Samples with an SCC of ≥250,000 cells mL-1 showed significant increases in IL-8 responses when compared with milk samples from healthy women. The milk microbiome of CM samples was dominated by streptococcal and staphylococcal species (89.9% combined median relative abundance). In contrast, the combined median streptococcal/staphylococcal relative levels were 75.4% and 66.3% in milks from asymptomatic (subclinical mastitis) and healthy groups, respectively. The Streptococcus genus was increased in samples with an SCC of ≥250,000, although this should be interpreted with caution. Thus, the index of ≥250,000 somatic cells mL-1 could be a reliable indicator of subclinical mastitis in humans and should aid future studies investigating the impact of subclinical mastitis on maternal health, breastfeeding behaviors, infant health, and development.
Importance: This pilot study suggests that SCC at a level of (greater than or equal to) 250,000 cells mL-1, as used in the dairy industry, is a suitable index to identify asymptomatic subclinical mastitis in lactating women since it reflects a significant increase in the inflammatory response compared to milk samples from healthy women. Using this index should aid studies into the short- and long-term consequences of subclinical mastitis for mother and infant.
{"title":"Somatic cell count as an indicator of subclinical mastitis and increased inflammatory response in asymptomatic lactating women.","authors":"Angeliki Angelopoulou, Hugh M B Harris, Alicja K Warda, Carol-Anne O'Shea, Aonghus Lavelle, C Anthony Ryan, Eugene Dempsey, Catherine Stanton, Colin Hill, R Paul Ross","doi":"10.1128/spectrum.04051-23","DOIUrl":"https://doi.org/10.1128/spectrum.04051-23","url":null,"abstract":"<p><p>Subclinical mastitis is an asymptomatic inflammatory condition that can be difficult to define and diagnose. In the dairy industry, subclinical mastitis is diagnosed by milk somatic cell counts (SCCs) of ≥250,000 cells mL<sup>-1</sup>. In this pilot study, we assessed the efficacy of this index to identify human subclinical mastitis by comparing SCC levels with the inflammatory response [interleukin-8 (IL-8) levels] in 37 samples from asymptomatic and 10 clinical mastitis (CM) lactating women. The milk microbiota was determined by 16S rRNA gene sequencing. The SCC of CM samples ranged from 310,000 to 6,600,000 cells mL<sup>-1</sup>. However, 14 of 37 (37.8%) asymptomatic samples had high SCC (250,000-460,000 cells mL<sup>-1</sup>), indicating subclinical mastitis. SCC levels significantly (<i>P</i> < 0.001) and positively correlated with milk IL-8 levels reflecting the escalating inflammatory response across subclinical and clinical mastitis samples. Samples with an SCC of ≥250,000 cells mL<sup>-1</sup> showed significant increases in IL-8 responses when compared with milk samples from healthy women. The milk microbiome of CM samples was dominated by streptococcal and staphylococcal species (89.9% combined median relative abundance). In contrast, the combined median streptococcal/staphylococcal relative levels were 75.4% and 66.3% in milks from asymptomatic (subclinical mastitis) and healthy groups, respectively. The <i>Streptococcus</i> genus was increased in samples with an SCC of ≥250,000, although this should be interpreted with caution. Thus, the index of ≥250,000 somatic cells mL<sup>-1</sup> could be a reliable indicator of subclinical mastitis in humans and should aid future studies investigating the impact of subclinical mastitis on maternal health, breastfeeding behaviors, infant health, and development.</p><p><strong>Importance: </strong>This pilot study suggests that SCC at a level of (greater than or equal to) 250,000 cells mL<sup>-1</sup>, as used in the dairy industry, is a suitable index to identify asymptomatic subclinical mastitis in lactating women since it reflects a significant increase in the inflammatory response compared to milk samples from healthy women. Using this index should aid studies into the short- and long-term consequences of subclinical mastitis for mother and infant.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.01054-24
Li Zhang, Binyang Zheng, Jing Lu, Haisheng Wu, Hailian Wu, Qi Zhang, Lei Jiao, Hongxing Pan, Jianfang Zhou
Yersinia pestis has a broad host range and has caused lethal bubonic and pneumonic plague in humans. With the emergence of multiple resistant strains and the potential for biothreat use, there is an urgent need for new therapeutic strategies that can protect populations from natural or deliberate infection. Targeting F1 has been proven to be the main strategy for developing vaccines and therapeutic antibodies, but data on anti-F1 antibodies, especially in humans, are scarce. To date, three human anti-F1 monoclonal antibodies (m252, αF1Ig2, and αF1Ig8) from naive populations have been reported. Here, we constructed an antibody library from vaccinees immunized with the plague subunit vaccine IIa by phage display. The genetic basis, epitopes, and biological functions of the obtained mAbs were assessed and evaluated in plague-challenged mice. Three human mAbs, namely, F3, F19, and F23, were identified. Their biolayer responses were 0.4, 0.6, and 0.6 nm, respectively. The dissociation constants (KD) of the F1 antigen were 1 pM, 0.165 nM, and 1 pM, respectively. Although derived from distinct Ab lineages, that is, VH3-30-D3-10-JH4 (F3&F23) and VH3-43-D6-19-JH4 (F19), these mAbs share similar binding sites in F1 with some overlap with αF1Ig8 but are distinct from αF1Ig2. Each of them provided a significant protective effect for Balb/c mice against a 100 median lethal dose (MLD) challenge of a virulent Y. pestis strain when administered at a dose of 100 µg. No synergistic or antagonistic effects were observed among them. These mAbs are novel and excellent candidates for further drug development and use in clinical practice.IMPORTANCEIn this study, we identified three human monoclonal antibodies with a high affinity to F1 protein of Yersinia pestis. We discovered that they have relatively lower somatic hypermutations compared with antibodies, m252, αF1Ig2, and αF1Ig8, derived from the naive library reported previously. We also observed that these mAbs share similar binding sites in F1 with some overlapping with αF1Ig8 but distinct from that of αF1Ig2. Furthermore, each of them could provide complete protection for mice against a lethal dose of Yersinia pestis challenge. Our data provided new insights into the anti-F1 Ab repertories and their associated epitopes during vaccination in humans. The findings support the additional novel protective human anti-F1Abs for potential therapeutics against plaque.
鼠疫耶尔森菌的宿主范围很广,曾在人类中引起致命的鼠疫和肺鼠疫。随着多种抗药性菌株的出现和生物威胁的潜在使用,迫切需要新的治疗策略来保护人群免受自然或蓄意感染。靶向 F1 已被证明是开发疫苗和治疗性抗体的主要策略,但有关抗 F1 抗体(尤其是人类抗 F1 抗体)的数据却很少。迄今为止,已报道了三种来自天真人群的人类抗 F1 单克隆抗体(m252、αF1Ig2 和 αF1Ig8)。在这里,我们通过噬菌体展示技术从接种鼠疫亚单位疫苗 IIa 的接种者中构建了一个抗体库。我们在鼠疫感染小鼠身上评估和评价了所获 mAbs 的遗传基础、表位和生物学功能。结果发现了三种人类 mAbs,即 F3、F19 和 F23。它们的生物层反应分别为 0.4、0.6 和 0.6 nm。F1 抗原的解离常数(KD)分别为 1 pM、0.165 nM 和 1 pM。虽然这些 mAbs 来自不同的抗体谱系,即 VH3-30-D3-10-JH4(F3&F23)和 VH3-43-D6-19-JH4(F19),但它们在 F1 中的结合位点相似,与 αF1Ig8 有一些重叠,但与αF1Ig2 不同。给 Balb/c 小鼠注射 100 µg 剂量时,它们都能对毒性鼠疫 Y. 菌株的 100 中位致死剂量(MLD)挑战产生明显的保护作用。它们之间没有协同或拮抗作用。在这项研究中,我们发现了三种与鼠疫耶尔森菌 F1 蛋白具有高亲和力的人类单克隆抗体。我们发现,与之前报道的来自天真库的抗体m252、αF1Ig2和αF1Ig8相比,它们的体细胞高突变率相对较低。我们还观察到,这些 mAbs 在 F1 中具有相似的结合位点,其中一些与 αF1Ig8 重叠,但与αF1Ig2 不同。此外,它们都能完全保护小鼠免受致命剂量鼠疫耶尔森菌的侵袭。我们的数据为人类疫苗接种过程中的抗 F1 Ab 重排及其相关表位提供了新的见解。这些发现支持将更多新型保护性人类抗F1抗体用于潜在的斑块治疗。
{"title":"Evaluation of human antibodies from vaccinated volunteers for protection against <i>Yersinia pestis</i> infection.","authors":"Li Zhang, Binyang Zheng, Jing Lu, Haisheng Wu, Hailian Wu, Qi Zhang, Lei Jiao, Hongxing Pan, Jianfang Zhou","doi":"10.1128/spectrum.01054-24","DOIUrl":"https://doi.org/10.1128/spectrum.01054-24","url":null,"abstract":"<p><p><i>Yersinia pestis</i> has a broad host range and has caused lethal bubonic and pneumonic plague in humans. With the emergence of multiple resistant strains and the potential for biothreat use, there is an urgent need for new therapeutic strategies that can protect populations from natural or deliberate infection. Targeting F1 has been proven to be the main strategy for developing vaccines and therapeutic antibodies, but data on anti-F1 antibodies, especially in humans, are scarce. To date, three human anti-F1 monoclonal antibodies (m252, αF1Ig2, and αF1Ig8) from naive populations have been reported. Here, we constructed an antibody library from vaccinees immunized with the plague subunit vaccine IIa by phage display. The genetic basis, epitopes, and biological functions of the obtained mAbs were assessed and evaluated in plague-challenged mice. Three human mAbs, namely, F3, F19, and F23, were identified. Their biolayer responses were 0.4, 0.6, and 0.6 nm, respectively. The dissociation constants (K<sub>D</sub>) of the F1 antigen were 1 pM, 0.165 nM, and 1 pM, respectively. Although derived from distinct Ab lineages, that is, VH3-30-D3-10-JH4 (F3&F23) and VH3-43-D6-19-JH4 (F19), these mAbs share similar binding sites in F1 with some overlap with αF1Ig8 but are distinct from αF1Ig2. Each of them provided a significant protective effect for Balb/c mice against a 100 median lethal dose (MLD) challenge of a virulent <i>Y. pestis</i> strain when administered at a dose of 100 µg. No synergistic or antagonistic effects were observed among them. These mAbs are novel and excellent candidates for further drug development and use in clinical practice.IMPORTANCEIn this study, we identified three human monoclonal antibodies with a high affinity to F1 protein of <i>Yersinia pestis</i>. We discovered that they have relatively lower somatic hypermutations compared with antibodies, m252, αF1Ig2, and αF1Ig8, derived from the naive library reported previously. We also observed that these mAbs share similar binding sites in F1 with some overlapping with αF1Ig8 but distinct from that of αF1Ig2. Furthermore, each of them could provide complete protection for mice against a lethal dose of <i>Yersinia pestis</i> challenge. Our data provided new insights into the anti-F1 Ab repertories and their associated epitopes during vaccination in humans. The findings support the additional novel protective human anti-F1Abs for potential therapeutics against plaque.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The performance of BACT/ALERT FA/FN Plus (France) blood culture containing a novel resin, DL (China) blood culture containing common resin, and adsorbent-free REDOX (USA) blood culture relying on dilution for antimicrobial neutralization at %peak serum concentration was evaluated by measuring the recovery of organisms and time to detection (TTD) in nine simulated microorganism-antimicrobial combination blood cultures. Significant differences were observed in the recovery rates among the aerobic media: 87.5% for BACT/ALERT media, 42.9% for DL media, and 12.5% for REDOX media. In contrast, no statistical difference was found in the TTD between FA Plus media and DL aerobic media. For the anaerobic media, the recovery rates were 91.4% for BACT/ALERT media, 2.9% for DL media, and 14.3% for REDOX media, with significant differences only between BACT/ALERT FN Plus media and the others. Among the seven main antimicrobial categories, only BACT/ALERT FA/FN Plus culture media demonstrated high recovery of microorganisms, with the exception of carbapenems. The DL culture media exhibited a relatively high recovery rate of microorganisms in the presence of piperacillin/tazobactam, levofloxacin, and gentamicin, but only in aerobic conditions. Conversely, REDOX media displayed microorganism recovery solely in the presence of gentamicin. BACT/ALERT FA/FN Plus culture media with novel resin showed absolute advantages over DL and REDOX culture media and can, therefore, be selectively applied in clinical settings when antimicrobials are used prior to blood collection. DL culture media, containing common resin, outperformed adsorbent-free dilution-based REDOX culture media, making it a viable backup option. There is a need to focus on improving the neutralization of carbapenems with current inefficiency in all three medias.
Importance: We present a study on performance comparison of three different commercial culture media for neutralization of antibiotic effects in simulated blood cultures. BACT/ALERT (FA Plus and FN Plus) culture media with novel resin showed absolute advantages over DL and REDOX culture media at %PSL concentration of antimicrobials.
{"title":"Comparison and evaluation of neutralization of clinically frequently used antimicrobial agents using three different culture media in simulated blood cultures.","authors":"Yaping Hang, Jianqiu Xiong, Longhua Hu, Yanhui Chen, Shan Zou, Xueyao Fang, Yanping Xiao, Xingwei Cao, Hong Lou, Xiuzhen Li, Yanhua Liu, Qiaoshi Zhong","doi":"10.1128/spectrum.00979-24","DOIUrl":"https://doi.org/10.1128/spectrum.00979-24","url":null,"abstract":"<p><p>The performance of BACT/ALERT FA/FN Plus (France) blood culture containing a novel resin, DL (China) blood culture containing common resin, and adsorbent-free REDOX (USA) blood culture relying on dilution for antimicrobial neutralization at %peak serum concentration was evaluated by measuring the recovery of organisms and time to detection (TTD) in nine simulated microorganism-antimicrobial combination blood cultures. Significant differences were observed in the recovery rates among the aerobic media: 87.5% for BACT/ALERT media, 42.9% for DL media, and 12.5% for REDOX media. In contrast, no statistical difference was found in the TTD between FA Plus media and DL aerobic media. For the anaerobic media, the recovery rates were 91.4% for BACT/ALERT media, 2.9% for DL media, and 14.3% for REDOX media, with significant differences only between BACT/ALERT FN Plus media and the others. Among the seven main antimicrobial categories, only BACT/ALERT FA/FN Plus culture media demonstrated high recovery of microorganisms, with the exception of carbapenems. The DL culture media exhibited a relatively high recovery rate of microorganisms in the presence of piperacillin/tazobactam, levofloxacin, and gentamicin, but only in aerobic conditions. Conversely, REDOX media displayed microorganism recovery solely in the presence of gentamicin. BACT/ALERT FA/FN Plus culture media with novel resin showed absolute advantages over DL and REDOX culture media and can, therefore, be selectively applied in clinical settings when antimicrobials are used prior to blood collection. DL culture media, containing common resin, outperformed adsorbent-free dilution-based REDOX culture media, making it a viable backup option. There is a need to focus on improving the neutralization of carbapenems with current inefficiency in all three medias.</p><p><strong>Importance: </strong>We present a study on performance comparison of three different commercial culture media for neutralization of antibiotic effects in simulated blood cultures. BACT/ALERT (FA Plus and FN Plus) culture media with novel resin showed absolute advantages over DL and REDOX culture media at %PSL concentration of antimicrobials.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.00083-24
Madhur Wyatt, Ankan Choudhury, Gabriella Von Dohlen, Jeffery L Heileson, Jeffrey S Forsse, Sumudu Rajakaruna, Manja Zec, Malak M Tfaily, Leigh Greathouse
Evidence indicates that both vitamin D and the gut microbiome are involved in the process of colon carcinogenesis. However, it is unclear what effects supplemental vitamin D3 has on the gut microbiome and its metabolites in healthy adults. We conducted a double-blind, randomized, placebo-controlled trial to identify the acute and long-term microbiota structural and metabolite changes that occur in response to a moderate dose (4,000 IU) of vitamin D3 for 12 weeks in healthy adults. Our results demonstrated a significant increase in serum 25-hydroxy-vitamin D (25(OH)D) in the treatment group compared to placebo (P < 0.0001). Vitamin D3 significantly increased compositional similarity (P < 0.0001) in the treatment group, and enriched members of the Bifidobacteriaceae family. We also identified a significant inverse relationship between the percent change in serum 25(OH)D and microbial stability in the treatment group (R = -0.52, P < 0.019). Furthermore, vitamin D3 supplementation resulted in notable metabolic shifts, in addition to resulting in a drastic rewiring of key gut microbial-metabolic associations. In conclusion, we show that a moderate dose of vitamin D3 among healthy adults has unique acute and persistent effects on the fecal microbiota, and suggest novel mechanisms by which vitamin D may affect the host-microbiota relationship.
Importance: Preventative measures to reduce the rise in early-onset colorectal cancer are of critical need. Both vitamin D, dietary and serum levels, and the gut microbiome are implicated in the etiology of colorectal cancer. By understanding the intimate relationship between vitamin D, the gut microbiome, and its metabolites, we may be able to identify key mechanisms that can be targeted for intervention, including inflammation and metabolic dysfunction. Furthermore, the similarity of vitamin D to cholesterol, which is metabolized by the gut microbiome, gives precedence to its ability to produce metabolites that can be further studied and leveraged for controlling colorectal cancer incidence and mortality.
有证据表明,维生素 D 和肠道微生物组都参与了结肠癌的发生过程。然而,目前还不清楚补充维生素 D3 对健康成年人的肠道微生物群及其代谢物有什么影响。我们进行了一项双盲、随机、安慰剂对照试验,以确定健康成年人在服用中等剂量(4,000 IU)维生素 D3 12 周后,微生物群结构和代谢物会发生哪些急性和长期变化。我们的研究结果表明,与安慰剂相比,治疗组的血清 25- 羟基维生素 D(25(OH)D)明显增加(P < 0.0001)。维生素 D3 明显增加了治疗组的成分相似性(P < 0.0001),并丰富了双歧杆菌科的成员。我们还发现,在治疗组中,血清 25(OH)D 百分比变化与微生物稳定性之间存在明显的反比关系(R = -0.52,P < 0.019)。此外,维生素 D3 的补充除了导致关键肠道微生物-代谢关联的急剧重构外,还导致了显著的代谢转变。总之,我们的研究表明,健康成年人服用适量维生素 D3 会对粪便微生物群产生独特的急性和持续性影响,并提出了维生素 D 影响宿主与微生物群关系的新机制:亟需采取预防措施,降低早发性结直肠癌的发病率。膳食和血清中的维生素 D 水平以及肠道微生物群都与结直肠癌的病因有关。通过了解维生素 D、肠道微生物组及其代谢物之间的密切关系,我们或许能找出可作为干预目标的关键机制,包括炎症和代谢功能障碍。此外,维生素 D 与胆固醇相似,而胆固醇是由肠道微生物组代谢的,因此维生素 D 能够产生代谢物,而这些代谢物可被进一步研究并用于控制结直肠癌的发病率和死亡率。
{"title":"Randomized control trial of moderate dose vitamin D alters microbiota stability and metabolite networks in healthy adults.","authors":"Madhur Wyatt, Ankan Choudhury, Gabriella Von Dohlen, Jeffery L Heileson, Jeffrey S Forsse, Sumudu Rajakaruna, Manja Zec, Malak M Tfaily, Leigh Greathouse","doi":"10.1128/spectrum.00083-24","DOIUrl":"https://doi.org/10.1128/spectrum.00083-24","url":null,"abstract":"<p><p>Evidence indicates that both vitamin D and the gut microbiome are involved in the process of colon carcinogenesis. However, it is unclear what effects supplemental vitamin D<sub>3</sub> has on the gut microbiome and its metabolites in healthy adults. We conducted a double-blind, randomized, placebo-controlled trial to identify the acute and long-term microbiota structural and metabolite changes that occur in response to a moderate dose (4,000 IU) of vitamin D<sub>3</sub> for 12 weeks in healthy adults. Our results demonstrated a significant increase in serum 25-hydroxy-vitamin D (25(OH)D) in the treatment group compared to placebo (<i>P</i> < 0.0001). Vitamin D<sub>3</sub> significantly increased compositional similarity (<i>P</i> < 0.0001) in the treatment group, and enriched members of the Bifidobacteriaceae family. We also identified a significant inverse relationship between the percent change in serum 25(OH)D and microbial stability in the treatment group (<i>R</i> = -0.52, <i>P</i> < 0.019). Furthermore, vitamin D<sub>3</sub> supplementation resulted in notable metabolic shifts, in addition to resulting in a drastic rewiring of key gut microbial-metabolic associations. In conclusion, we show that a moderate dose of vitamin D<sub>3</sub> among healthy adults has unique acute and persistent effects on the fecal microbiota, and suggest novel mechanisms by which vitamin D may affect the host-microbiota relationship.</p><p><strong>Importance: </strong>Preventative measures to reduce the rise in early-onset colorectal cancer are of critical need. Both vitamin D, dietary and serum levels, and the gut microbiome are implicated in the etiology of colorectal cancer. By understanding the intimate relationship between vitamin D, the gut microbiome, and its metabolites, we may be able to identify key mechanisms that can be targeted for intervention, including inflammation and metabolic dysfunction. Furthermore, the similarity of vitamin D to cholesterol, which is metabolized by the gut microbiome, gives precedence to its ability to produce metabolites that can be further studied and leveraged for controlling colorectal cancer incidence and mortality.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bone and soft tissue infections caused by biofilm-forming bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), remain a significant clinical challenge. While the control of local infection is necessary, systemic treatment is also required, and biofilm eradication is a critical target for successful management. Topical antibiotic treatments, such as antibiotic-loaded bone cement (ALBC), have been used for some time, and continuous local antibiotic perfusion therapy, a less invasive method, has been developed by our group. However, the optimal antibiotics and concentrations for biofilms of clinical isolates are still not well understood. We examined the efficacy of high concentrations of gentamicin against MRSA biofilms and the role of gentamicin resistance genes in biofilm eradication. We collected 101 MRSA samples from a hospital in Japan and analyzed their gene properties, including methicillin and gentamicin resistance, and their minimum biofilm eradication concentration (MBEC) values. Our results showed that high concentrations of gentamicin are effective against MRSA biofilms and that even concentrations lower than the MBEC value could eliminate biofilms after prolonged exposure. We also identified three aminoglycoside/gentamicin resistance genes [aac(6')-aph(2″), aph(3')-III, and ant(4')-IA] and found that the presence or absence of these genes may inform the selection of treatments. It was also found that possession of the aac(6')-aph(2″) gene correlated with the minimum inhibitory concentration/MBEC values of gentamicin. Although this study provides insight into the efficacy of gentamicin against MRSA biofilms and the role of gentamicin resistance genes, careful selection of the optimal treatment strategy is needed for clinical application.
Importance: Our analysis of 101 MRSA clinical isolates has provided valuable insights that could enhance treatment selection for biofilm infections in orthopedics. We found that high concentrations of gentamicin were effective against MRSA biofilms, and even prolonged exposure to concentrations lower than the minimum biofilm eradication concentration (MBEC) value could eliminate biofilms. The presence of the aac(6')-aph(2″) gene, an aminoglycoside resistance gene, was found to correlate with the minimum inhibitory concentration (MIC) and MBEC values of gentamicin, providing a potential predictive tool for treatment susceptibility. These results suggest that extended high concentrations of local gentamicin treatment could effectively eliminate MRSA biofilms in orthopedic infections. Furthermore, testing for gentamicin MIC or the possession of the aac(6')-aph(2″) gene could help select treatment, including topical gentamicin administration and surgical debridement.
{"title":"Effective biofilm eradication in MRSA isolates with aminoglycoside-modifying enzyme genes using high-concentration and prolonged gentamicin treatment.","authors":"Kohei Ando, Satoshi Miyahara, Shuhei Hanada, Kazumasa Fukuda, Mitsumasa Saito, Akinori Sakai, Akihiro Maruo, Yukichi Zenke","doi":"10.1128/spectrum.00647-24","DOIUrl":"https://doi.org/10.1128/spectrum.00647-24","url":null,"abstract":"<p><p>Bone and soft tissue infections caused by biofilm-forming bacteria, such as methicillin-resistant <i>Staphylococcus aureus</i> (MRSA), remain a significant clinical challenge. While the control of local infection is necessary, systemic treatment is also required, and biofilm eradication is a critical target for successful management. Topical antibiotic treatments, such as antibiotic-loaded bone cement (ALBC), have been used for some time, and continuous local antibiotic perfusion therapy, a less invasive method, has been developed by our group. However, the optimal antibiotics and concentrations for biofilms of clinical isolates are still not well understood. We examined the efficacy of high concentrations of gentamicin against MRSA biofilms and the role of gentamicin resistance genes in biofilm eradication. We collected 101 MRSA samples from a hospital in Japan and analyzed their gene properties, including methicillin and gentamicin resistance, and their minimum biofilm eradication concentration (MBEC) values. Our results showed that high concentrations of gentamicin are effective against MRSA biofilms and that even concentrations lower than the MBEC value could eliminate biofilms after prolonged exposure. We also identified three aminoglycoside/gentamicin resistance genes [<i>aac(6')-aph(2″)</i>, <i>aph(3')-III</i>, and <i>ant(4')-IA</i>] and found that the presence or absence of these genes may inform the selection of treatments. It was also found that possession of the <i>aac(6')-aph(2″</i>) gene correlated with the minimum inhibitory concentration/MBEC values of gentamicin. Although this study provides insight into the efficacy of gentamicin against MRSA biofilms and the role of gentamicin resistance genes, careful selection of the optimal treatment strategy is needed for clinical application.</p><p><strong>Importance: </strong>Our analysis of 101 MRSA clinical isolates has provided valuable insights that could enhance treatment selection for biofilm infections in orthopedics. We found that high concentrations of gentamicin were effective against MRSA biofilms, and even prolonged exposure to concentrations lower than the minimum biofilm eradication concentration (MBEC) value could eliminate biofilms. The presence of the <i>aac(6')-aph(2″)</i> gene, an aminoglycoside resistance gene, was found to correlate with the minimum inhibitory concentration (MIC) and MBEC values of gentamicin, providing a potential predictive tool for treatment susceptibility. These results suggest that extended high concentrations of local gentamicin treatment could effectively eliminate MRSA biofilms in orthopedic infections. Furthermore, testing for gentamicin MIC or the possession of the <i>aac(6')-aph(2″)</i> gene could help select treatment, including topical gentamicin administration and surgical debridement.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142080881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.03812-23
Jiancai Xiao, Jing Xiao, Pengchao Gao, You Zhang, Binbin Yan, Hongli Wu, Yan Zhang
The widespread prevalence of saline environments poses a significant global environmental challenge. Salt stress, induced by saline soils, disrupts soil microecology and affects the plant-microbe-soil cycling process. Utilizing microbial fungicides stands as a primary strategy to mitigate salt stress-induced damage to plants and soils. This study investigated the influence of Bacillus subtilis (Bs) inoculation on the microbial community, assembly processes, and functional changes in bacteria and fungi in Glycyrrhiza uralensis Fisch. (licorice) seedlings under varying salt stress levels, primarily employing microbiomics techniques. Soil enzyme activities displayed a declining trend with increasing salt stress, which was mitigated by Bs inoculation. Microbiome analysis revealed a significant increase in bacterial and fungal operational taxonomic units, particularly in Ascomycetes and Nitrogen-fixing Bacteria, thereby enhancing soil denitrification. The abundance of Proteobacteria, Actinobacteriota, Bacteroidota, and Firmicutes in bacteria, as well as Ascomycota in fungi, increased with higher salt stress levels, a process facilitated by Bs inoculation. However, functional predictions indicated a reduction in the relative abundance of Dung Saprotrophs with Bs inoculation. Salt stress disrupted soil assembly processes, showcasing a continuous decline in diffusion limitation with increased salt concentration, where Bs inoculation reached a peak under moderate stress. In summary, this research elucidates the communication mechanism of Bs in enhancing salt tolerance in licorice from a microbiome perspective, contributing to a comprehensive understanding of abiotic and biotic factors.IMPORTANCELicorice is a herb that grows in deserts or saline soils. Enhancing the salt tolerance of licorice is necessary to maintain the quality of cultivated licorice and to ensure the supply of medicinal herbs. In the past, we have demonstrated the effectiveness of inoculation with Bacillus subtilis (Bs) to enhance the salt tolerance of licorice and revealed the key metabolic pathways for the development of salt tolerance through multi-omics. In this study, we used the microbiomics approach to reveal the plant-microbe-soil interactions at the level of inoculation of Bs affecting the dynamics of soil microbial communities from bacterial and fungal perspectives, thus bridging the interactions between biotic and abiotic factors.
{"title":"Enhanced salt tolerance in <i>Glycyrrhiza uralensis</i> Fisch. via <i>Bacillus subtilis</i> inoculation alters microbial community.","authors":"Jiancai Xiao, Jing Xiao, Pengchao Gao, You Zhang, Binbin Yan, Hongli Wu, Yan Zhang","doi":"10.1128/spectrum.03812-23","DOIUrl":"https://doi.org/10.1128/spectrum.03812-23","url":null,"abstract":"<p><p>The widespread prevalence of saline environments poses a significant global environmental challenge. Salt stress, induced by saline soils, disrupts soil microecology and affects the plant-microbe-soil cycling process. Utilizing microbial fungicides stands as a primary strategy to mitigate salt stress-induced damage to plants and soils. This study investigated the influence of <i>Bacillus subtilis</i> (Bs) inoculation on the microbial community, assembly processes, and functional changes in bacteria and fungi in <i>Glycyrrhiza uralensis</i> Fisch. (licorice) seedlings under varying salt stress levels, primarily employing microbiomics techniques. Soil enzyme activities displayed a declining trend with increasing salt stress, which was mitigated by Bs inoculation. Microbiome analysis revealed a significant increase in bacterial and fungal operational taxonomic units, particularly in Ascomycetes and Nitrogen-fixing Bacteria, thereby enhancing soil denitrification. The abundance of Proteobacteria, Actinobacteriota, Bacteroidota, and Firmicutes in bacteria, as well as Ascomycota in fungi, increased with higher salt stress levels, a process facilitated by Bs inoculation. However, functional predictions indicated a reduction in the relative abundance of Dung Saprotrophs with Bs inoculation. Salt stress disrupted soil assembly processes, showcasing a continuous decline in diffusion limitation with increased salt concentration, where Bs inoculation reached a peak under moderate stress. In summary, this research elucidates the communication mechanism of Bs in enhancing salt tolerance in licorice from a microbiome perspective, contributing to a comprehensive understanding of abiotic and biotic factors.IMPORTANCELicorice is a herb that grows in deserts or saline soils. Enhancing the salt tolerance of licorice is necessary to maintain the quality of cultivated licorice and to ensure the supply of medicinal herbs. In the past, we have demonstrated the effectiveness of inoculation with <i>Bacillus subtilis</i> (Bs) to enhance the salt tolerance of licorice and revealed the key metabolic pathways for the development of salt tolerance through multi-omics. In this study, we used the microbiomics approach to reveal the plant-microbe-soil interactions at the level of inoculation of Bs affecting the dynamics of soil microbial communities from bacterial and fungal perspectives, thus bridging the interactions between biotic and abiotic factors.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1128/spectrum.01103-24
Olivér Jáger, Csilla Szebenyi, Tammam Khaliefeh Siliman Abu Saleem, Anna Molnár, Vanda Kovács, Karina Kiss, Mónika Homa, Bernadett Vágó, Sándor Kiss-Vetráb, Mónika Varga, Rita Sinka, Csaba Vágvölgyi, Gábor Nagy, Tamás Papp
Survival factor 1 (Svf1) protein has been described in some ascomycetous fungi where it was found to be contributing to several essential physiological processes, such as response to osmotic, oxidative and cold stresses, sphingolipid biosynthesis, morphogenesis, sporulation, antifungal resistance, and pathogenicity. It was also suggested that it can be a novel central regulator affecting the expression of various genes. In the present study, function of this protein and the encoding genes is described for the first time in a fungus (i.e., in Mucor lusitanicus) belonging to the order Mucorales. M. lusitanicus has two putative svf1 genes named svf1a and svf1b. Expression of both genes was proven. Although the expression of svf1a was affected by several environmental stresses and knocking out the gene affected adaptation to low temperatures and the sporulation ability, the main survival factor functions, such as participation in the maintenance of the viability, the response to oxidative and cold stresses, and the sphingolipid biosynthesis, could be associated with Svf1b, suggesting a central regulatory role to this protein. Interestingly, knockout of both genes affected the pathogenicity of the fungus in a Drosophila model.
Importance: Mucor lusitanicus is a widely used model organism to study various biological processes in the basal fungal group Mucorales. Several members of this group can be agents of mucormycosis, an opportunistic fungal infection, which is associated with high mortality, rapid progression, and wide resistance to the commonly used antifungal agents. Svf1 proteins have so far only been identified in fungi, where they have been involved in pathogenicity and resistance to antifungal agents in many cases. Only a limited number of factors affecting the stress response, antifungal resistance, and virulence of Mucorales fungi have been revealed. Elucidating the function of a fungus-specific protein that may regulate these processes may bring us closer to understanding the pathogenesis of these fungi.
{"title":"Functional characterization of two survival factor 1 genes in <i>Mucor lusitanicus</i>.","authors":"Olivér Jáger, Csilla Szebenyi, Tammam Khaliefeh Siliman Abu Saleem, Anna Molnár, Vanda Kovács, Karina Kiss, Mónika Homa, Bernadett Vágó, Sándor Kiss-Vetráb, Mónika Varga, Rita Sinka, Csaba Vágvölgyi, Gábor Nagy, Tamás Papp","doi":"10.1128/spectrum.01103-24","DOIUrl":"https://doi.org/10.1128/spectrum.01103-24","url":null,"abstract":"<p><p>Survival factor 1 (Svf1) protein has been described in some ascomycetous fungi where it was found to be contributing to several essential physiological processes, such as response to osmotic, oxidative and cold stresses, sphingolipid biosynthesis, morphogenesis, sporulation, antifungal resistance, and pathogenicity. It was also suggested that it can be a novel central regulator affecting the expression of various genes. In the present study, function of this protein and the encoding genes is described for the first time in a fungus (i.e., in <i>Mucor lusitanicus</i>) belonging to the order Mucorales. <i>M. lusitanicus</i> has two putative <i>svf1</i> genes named <i>svf1a</i> and <i>svf1b</i>. Expression of both genes was proven. Although the expression of <i>svf1a</i> was affected by several environmental stresses and knocking out the gene affected adaptation to low temperatures and the sporulation ability, the main survival factor functions, such as participation in the maintenance of the viability, the response to oxidative and cold stresses, and the sphingolipid biosynthesis, could be associated with Svf1b, suggesting a central regulatory role to this protein. Interestingly, knockout of both genes affected the pathogenicity of the fungus in a <i>Drosophila</i> model.</p><p><strong>Importance: </strong><i>Mucor lusitanicus</i> is a widely used model organism to study various biological processes in the basal fungal group Mucorales. Several members of this group can be agents of mucormycosis, an opportunistic fungal infection, which is associated with high mortality, rapid progression, and wide resistance to the commonly used antifungal agents. Svf1 proteins have so far only been identified in fungi, where they have been involved in pathogenicity and resistance to antifungal agents in many cases. Only a limited number of factors affecting the stress response, antifungal resistance, and virulence of Mucorales fungi have been revealed. Elucidating the function of a fungus-specific protein that may regulate these processes may bring us closer to understanding the pathogenesis of these fungi.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}