Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107386
K. M. Taufiqur Rahman , Ruqayyah Amaratunga , Xuan Yi Butzin , Abhyudai Singh , Tahmina Hossain , Nicholas C. Butzin
Objectives
Bacterial persisters are a subpopulation of multidrug-tolerant cells capable of surviving and resuming activity after exposure to bactericidal antibiotic concentrations, contributing to relapsing infections and the development of antibiotic resistance. In this study, we challenge the conventional view that persisters are metabolically dormant by providing compelling evidence that an isogenic population of Escherichia coli remains metabolically active in persistence.
Methods
Using transcriptomic analysis, we examined E. coli persisters at multiple time points following exposure to bactericidal concentrations of ampicillin (Amp). Some genes were consistently upregulated in Amp treated persisters compared to the untreated controls, a change that can only occur in metabolically active cells capable of increasing RNA levels.
Results
Some of the identified genes have been previously linked to persister cells, while others have not been associated with them before. If persister cells were metabolically dormant, gene expression changes over time would be minimal during Amp treatment. However, network analysis revealed major shifts in gene network activity at various time points of antibiotic exposure.
Conclusions
These findings reveal that persisters are metabolically active, non-dividing cells, thereby challenging the traditional view that they are dormant.
{"title":"Rethinking dormancy: Antibiotic persisters are metabolically active, non-growing cells","authors":"K. M. Taufiqur Rahman , Ruqayyah Amaratunga , Xuan Yi Butzin , Abhyudai Singh , Tahmina Hossain , Nicholas C. Butzin","doi":"10.1016/j.ijantimicag.2024.107386","DOIUrl":"10.1016/j.ijantimicag.2024.107386","url":null,"abstract":"<div><h3>Objectives</h3><div>Bacterial persisters are a subpopulation of multidrug-tolerant cells capable of surviving and resuming activity after exposure to bactericidal antibiotic concentrations, contributing to relapsing infections and the development of antibiotic resistance. In this study, we challenge the conventional view that persisters are metabolically dormant by providing compelling evidence that an isogenic population of <em>Escherichia coli</em> remains metabolically active in persistence.</div></div><div><h3>Methods</h3><div>Using transcriptomic analysis, we examined E. coli persisters at multiple time points following exposure to bactericidal concentrations of ampicillin (Amp). Some genes were consistently upregulated in Amp treated persisters compared to the untreated controls, a change that can only occur in metabolically active cells capable of increasing RNA levels.</div></div><div><h3>Results</h3><div>Some of the identified genes have been previously linked to persister cells, while others have not been associated with them before. If persister cells were metabolically dormant, gene expression changes over time would be minimal during Amp treatment. However, network analysis revealed major shifts in gene network activity at various time points of antibiotic exposure.</div></div><div><h3>Conclusions</h3><div>These findings reveal that persisters are metabolically active, non-dividing cells, thereby challenging the traditional view that they are dormant.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107386"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107398
Anand K. Keshri , Suraj S. Rawat , Anubha Chaudhary , Swati Sharma , Ananya Kapoor , Parul Mehra , Rimanpreet Kaur , Amit Mishra , Amit Prasad
Antimicrobial peptides (AMPs) represent a unique group of naturally occurring molecules having diverse biological activities, including potent antimicrobial properties. Among them, LL-37 has emerged as a significant player, demonstrating its multifaceted roles during bacterial, fungal, and viral infections, as well as exhibiting intriguing implications in cancer. This review delves into the versatile functions of LL-37, elucidating its mechanisms of action against microbial pathogens and its potential to modulate immune responses. We explored the efficacy of LL-37 in disrupting bacterial membranes, inhibiting fungal growth, and interfering with viral replication, highlighting its potential as a therapeutic agent against a wide array of infectious diseases. Furthermore, we discussed the emerging role of LL-37 in cancer immunity, where its immunomodulatory effects and direct cytotoxicity towards cancer cells offer novel avenues for cancer therapy in the near future. We provided a comprehensive overview of the activities of LL-37 across various diseases and underscored the importance of further research into harnessing the therapeutic potential of this potential antimicrobial peptide along with other suitable candidates.
{"title":"LL-37, the master antimicrobial peptide, its multifaceted role from combating infections to cancer immunity","authors":"Anand K. Keshri , Suraj S. Rawat , Anubha Chaudhary , Swati Sharma , Ananya Kapoor , Parul Mehra , Rimanpreet Kaur , Amit Mishra , Amit Prasad","doi":"10.1016/j.ijantimicag.2024.107398","DOIUrl":"10.1016/j.ijantimicag.2024.107398","url":null,"abstract":"<div><div>Antimicrobial peptides (AMPs) represent a unique group of naturally occurring molecules having diverse biological activities, including potent antimicrobial properties. Among them, LL-37 has emerged as a significant player, demonstrating its multifaceted roles during bacterial, fungal, and viral infections, as well as exhibiting intriguing implications in cancer. This review delves into the versatile functions of LL-37, elucidating its mechanisms of action against microbial pathogens and its potential to modulate immune responses. We explored the efficacy of LL-37 in disrupting bacterial membranes, inhibiting fungal growth, and interfering with viral replication, highlighting its potential as a therapeutic agent against a wide array of infectious diseases. Furthermore, we discussed the emerging role of LL-37 in cancer immunity, where its immunomodulatory effects and direct cytotoxicity towards cancer cells offer novel avenues for cancer therapy in the near future. We provided a comprehensive overview of the activities of LL-37 across various diseases and underscored the importance of further research into harnessing the therapeutic potential of this potential antimicrobial peptide along with other suitable candidates.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107398"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142791640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anakinra was approved by the European Medicines Agency and received Emergency Use Authorization by the United States Food and Drug Administration for patients with COVID-19 pneumonia at risk for severe respiratory failure (SRF) with blood levels of soluble urokinase plasminogen activator receptor (suPAR) ≥ 6 ng/mL. We report the final results of the phase II open-label single-arm SAVE trial in a large population.
Methods
Patients with COVID-19 pneumonia and suPAR levels ≥ 6 ng/mL received subcutaneous anakinra 100 mg once daily for 10 days. The primary outcome was the incidence of SRF by day 14. Secondary outcomes were 30-day mortality, incidence of SRF according to time delay for start of treatment, safety, and associations with the inflammatory burden of the host.
Results
From March 2020 to March 2022, a total of 992 patients were enrolled. The incidence of SRF was 18.8%, similar to the results of the phase III pivotal SAVE-MOREtrial. The overall 30-day mortality was 9.5%. Participants were divided into 4 subgroups according to time delay between symptoms onset and start of anakinra. The incidence of SRF was similar for all subgroups. Serious adverse events were reported in 15.4%; only 3 were possibly related to anakinra. The most common adverse event was increased liver function tests. A post hoc comparison with the pivotal phase III trial showed similar anakinra outcomes among patient subgroups by levels of inflammatory mediators and D-dimers.
Conclusions
Results support the efficacy of anakinra as being similar to that of the pivotal registrational trial for COVID-19 pneumonia. The lack of a comparator group is a limitation.
{"title":"Anakinra efficacy in COVID-19 pneumonia guided by soluble urokinase plasminogen activator receptor: Association with the inflammatory burden of the host","authors":"Evdoxia Kyriazopoulou , Karolina Akinosoglou , Eleni Florou , Elli Kouriannidi , Artemis Bogosian , Olga Tsachouridou , Konstantinos N. Syrigos , Nikolaos Gatselis , Haralampos Milionis , Ilias C. Papanikolaou , Styliani Sympardi , Maria Dafni , Antonia Alevizou , Alexia-Vasiliki Amvrazi , Errika Alexandrou , Kyprianos Archontoulis , Katerina Argyraki , Zoi Alexiou , Yakinthi Georgiou , Dimitra Gkogka , Evangelos J. Giamarellos-Bourboulis","doi":"10.1016/j.ijantimicag.2024.107405","DOIUrl":"10.1016/j.ijantimicag.2024.107405","url":null,"abstract":"<div><h3>Background</h3><div>Anakinra was approved by the European Medicines Agency and received Emergency Use Authorization by the United States Food and Drug Administration for patients with COVID-19 pneumonia at risk for severe respiratory failure (SRF) with blood levels of soluble urokinase plasminogen activator receptor (suPAR) ≥ 6 ng/mL. We report the final results of the phase II open-label single-arm SAVE trial in a large population.</div></div><div><h3>Methods</h3><div>Patients with COVID-19 pneumonia and suPAR levels ≥ 6 ng/mL received subcutaneous anakinra 100 mg once daily for 10 days. The primary outcome was the incidence of SRF by day 14. Secondary outcomes were 30-day mortality, incidence of SRF according to time delay for start of treatment, safety, and associations with the inflammatory burden of the host.</div></div><div><h3>Results</h3><div>From March 2020 to March 2022, a total of 992 patients were enrolled. The incidence of SRF was 18.8%, similar to the results of the phase III pivotal SAVE-MOREtrial. The overall 30-day mortality was 9.5%. Participants were divided into 4 subgroups according to time delay between symptoms onset and start of anakinra. The incidence of SRF was similar for all subgroups. Serious adverse events were reported in 15.4%; only 3 were possibly related to anakinra. The most common adverse event was increased liver function tests. A post hoc comparison with the pivotal phase III trial showed similar anakinra outcomes among patient subgroups by levels of inflammatory mediators and D-dimers.</div></div><div><h3>Conclusions</h3><div>Results support the efficacy of anakinra as being similar to that of the pivotal registrational trial for COVID-19 pneumonia. The lack of a comparator group is a limitation.</div></div><div><h3>Trial Registration</h3><div>ClinicalTrials.gov, NCT04357366</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107405"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142794597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107395
Maheswaran Easwaran , Rajiv Gandhi Govindaraj , Misagh Naderi , Michal Brylinski , Mahanama De Zoysa , Hyun-Jin Shin
Objective
The emergence of bacteriophage-encoded endolysins hold significant promise as novel antibacterial agents, particularly against the growing threat of antibiotic-resistant bacteria. Therefore, we investigated the phage ФEcSw endolysin to enhance the lytic activity against multi-drug-resistant Escherichia coli Sw1 through site-directed mutagenesis (SDM) guided by in silico identification of critical residues.
Methods
A computational analysis was conducted to elucidate the protein folding pattern, identify the active domains, and recognize critical residues of ФEcSw endolysin. Structural similarity-based docking simulations were employed to identify residues potentially involved in both recognition and cleavage of the bacterial peptidoglycan. Phage endolysin was amplified, cloned, expressed, and purified from phage ФEcSw. Pure endolysin (EL) activity was subsequently validated through SDM.
Results
Our studies revealed both open and closed conformations of ФEcSw endolysin within specific residue ranges (51–60 and 128–141). Notably, the active site was identified and contains the crucial catalytic residues, Glu19 and Asp34. A time-kill assay demonstrated that the holin (HL) – EL effectively reduced E. coli Sw1 growth by 46% within 12 h. Furthermore, treatment with HL, EL, and HL-EL significantly increased bacterial membrane permeability (11%, 74%, and 85%, respectively) within just 1 h. Importantly, SDM identified a double mutant (K19/H34) of the endolysin exhibiting the highest lytic activity compared to the wild-type and other mutants (E19D, E19K, D34E, and D34H) due to increase net charge from +3.23 to +6.29.
Conclusions
Our findings demonstrate that phage endolysins and HLs or engineered endolysin hold significant potential as therapeutic agents to combat multidrug-resistant bacterial infections.
{"title":"Evaluating the antibacterial activity of engineered phage ФEcSw endolysin against multidrug-resistant Escherichia coli strain Sw1","authors":"Maheswaran Easwaran , Rajiv Gandhi Govindaraj , Misagh Naderi , Michal Brylinski , Mahanama De Zoysa , Hyun-Jin Shin","doi":"10.1016/j.ijantimicag.2024.107395","DOIUrl":"10.1016/j.ijantimicag.2024.107395","url":null,"abstract":"<div><h3>Objective</h3><div>The emergence of bacteriophage-encoded endolysins hold significant promise as novel antibacterial agents, particularly against the growing threat of antibiotic-resistant bacteria. Therefore, we investigated the phage ФEcSw endolysin to enhance the lytic activity against multi-drug-resistant <em>Escherichia coli</em> Sw1 through site-directed mutagenesis (SDM) guided by in silico identification of critical residues.</div></div><div><h3>Methods</h3><div>A computational analysis was conducted to elucidate the protein folding pattern, identify the active domains, and recognize critical residues of ФEcSw endolysin. Structural similarity-based docking simulations were employed to identify residues potentially involved in both recognition and cleavage of the bacterial peptidoglycan. Phage endolysin was amplified, cloned, expressed, and purified from phage ФEcSw. Pure endolysin (EL) activity was subsequently validated through SDM.</div></div><div><h3>Results</h3><div>Our studies revealed both open and closed conformations of ФEcSw endolysin within specific residue ranges (51–60 and 128–141). Notably, the active site was identified and contains the crucial catalytic residues, Glu19 and Asp34. A time-kill assay demonstrated that the holin (HL) – EL effectively reduced <em>E. coli</em> Sw1 growth by 46% within 12 h. Furthermore, treatment with HL, EL, and HL-EL significantly increased bacterial membrane permeability (11%, 74%, and 85%, respectively) within just 1 h. Importantly, SDM identified a double mutant (K19/H34) of the endolysin exhibiting the highest lytic activity compared to the wild-type and other mutants (E19D, E19K, D34E, and D34H) due to increase net charge from +3.23 to +6.29.</div></div><div><h3>Conclusions</h3><div>Our findings demonstrate that phage endolysins and HLs or engineered endolysin hold significant potential as therapeutic agents to combat multidrug-resistant bacterial infections.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107395"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142755100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107416
Philippe Gautret , Jean-Christophe Lagier , Philippe Parola , Van Thuan Hoang , Line Meddeb , Morgane Mailhe , Barbara Doudier , Johan Courjon , Valérie Giordanengo , Vera Esteves Vieira , Hervé Tissot Dupont , Stéphane Honoré , Philippe Colson , Eric Chabrière , Bernard La Scola , Jean-Marc Rolain , Philippe Brouqui , Didier Raoult
{"title":"Retraction notice to “Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial” [International Journal of Antimicrobial Agents 56 (2020), 105949]","authors":"Philippe Gautret , Jean-Christophe Lagier , Philippe Parola , Van Thuan Hoang , Line Meddeb , Morgane Mailhe , Barbara Doudier , Johan Courjon , Valérie Giordanengo , Vera Esteves Vieira , Hervé Tissot Dupont , Stéphane Honoré , Philippe Colson , Eric Chabrière , Bernard La Scola , Jean-Marc Rolain , Philippe Brouqui , Didier Raoult","doi":"10.1016/j.ijantimicag.2024.107416","DOIUrl":"10.1016/j.ijantimicag.2024.107416","url":null,"abstract":"","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107416"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142894254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107384
Panteha Torabian , Navraj Singh , James Crawford , Gabriela Gonzalez , Nicholas Burgado , Martina Videva , Aidan Miller , Janai Perdue , Milena Dinu , Anthony Pietropaoli , Thomas Gaborski , Lea Vacca Michel
Sepsis, a leading cause of death in hospitals, can be defined as a dysregulated host inflammatory response to infection, which can lead to tissue damage, organ failure and cardiovascular complications. Although there is no cure for sepsis, the condition is typically managed with broad-spectrum antibiotics to eliminate any potential bacterial source of infection. However, a potential side effect of antibiotic treatment is the enhanced release of bacterial extracellular vesicles (BEVs), membrane-bound nanoparticles containing proteins and other biological molecules from their parent bacterium. Some of the Gram-negative extracellular vesicle (EV) cargo, including peptidoglycan associated lipoprotein and outer membrane protein A, have been shown to induce both acute and chronic inflammation in host tissue. It was hypothesized that the antibiotic concentration and mechanism of action may affect the amount of released BEVs, which could potentially exacerbate the host inflammatory response. This study evaluated nine clinically relevant antibiotics for their effect on EV release from Escherichia coli. Several beta-lactam antibiotics caused significantly more EV release, while quinolone and aminoglycoside antibiotics caused less vesiculation. Further study is warranted to corroborate the correlation between an antibiotic's mechanism of action and its effect on EV release, but these results underline the importance of antibiotic choice when treating patients with sepsis.
败血症是导致医院患者死亡的主要原因，可定义为宿主对感染的炎症反应失调，可导致组织损伤、器官衰竭和心血管并发症。虽然败血症无法治愈，但通常会使用广谱抗生素来消除潜在的细菌感染源。然而，抗生素治疗的一个潜在副作用是增强细菌胞外小泡（BEVs）的释放，BEVs 是一种膜结合纳米颗粒，其母体细菌含有蛋白质和其他生物分子。一些革兰氏阴性 EV 货物，包括肽聚糖相关脂蛋白（Pal）和外膜蛋白 A（OmpA），已被证明能诱发宿主组织的急性和慢性炎症。我们推测，抗生素的浓度及其作用机制会对释放的 BEV 数量产生影响，从而有可能加剧宿主的炎症反应。在这项研究中，我们评估了九种临床相关抗生素对大肠杆菌释放 EV 的影响。几种β-内酰胺类抗生素导致了明显更多的EV释放，而喹诺酮类和氨基糖苷类抗生素导致的水泡相对较少。要证实抗生素的作用机制与其对 EV 释放的影响之间的相关性还需要进一步的研究，但这些结果强调了在治疗败血症患者时选择抗生素的重要性。
{"title":"Effect of clinically relevant antibiotics on bacterial extracellular vesicle release from Escherichia coli","authors":"Panteha Torabian , Navraj Singh , James Crawford , Gabriela Gonzalez , Nicholas Burgado , Martina Videva , Aidan Miller , Janai Perdue , Milena Dinu , Anthony Pietropaoli , Thomas Gaborski , Lea Vacca Michel","doi":"10.1016/j.ijantimicag.2024.107384","DOIUrl":"10.1016/j.ijantimicag.2024.107384","url":null,"abstract":"<div><div>Sepsis, a leading cause of death in hospitals, can be defined as a dysregulated host inflammatory response to infection, which can lead to tissue damage, organ failure and cardiovascular complications. Although there is no cure for sepsis, the condition is typically managed with broad-spectrum antibiotics to eliminate any potential bacterial source of infection. However, a potential side effect of antibiotic treatment is the enhanced release of bacterial extracellular vesicles (BEVs), membrane-bound nanoparticles containing proteins and other biological molecules from their parent bacterium. Some of the Gram-negative extracellular vesicle (EV) cargo, including peptidoglycan associated lipoprotein and outer membrane protein A, have been shown to induce both acute and chronic inflammation in host tissue. It was hypothesized that the antibiotic concentration and mechanism of action may affect the amount of released BEVs, which could potentially exacerbate the host inflammatory response. This study evaluated nine clinically relevant antibiotics for their effect on EV release from <em>Escherichia coli</em>. Several beta-lactam antibiotics caused significantly more EV release, while quinolone and aminoglycoside antibiotics caused less vesiculation. Further study is warranted to corroborate the correlation between an antibiotic's mechanism of action and its effect on EV release, but these results underline the importance of antibiotic choice when treating patients with sepsis.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107384"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107382
Bosco R. Matamoros , Carlos Serna , Emilia Wedel , Natalia Montero , Finn Kirpekar , Bruno Gonzalez-Zorn
NpmA and NpmB are 16S rRNA methyltransferases that act on residue A1408 and confer high-level resistance to almost all aminoglycosides; however, these methyltransferases are rarely reported. A novel gene, npmC, was identified after analysisng all world-wide available metagenomic projects in a One Health context. This gene has a high level of similarity (91.5%) with npmA and up to 92.7% similarity at amino acidic level. The protein encoded by this gene presents the conserved motifs required for A1408 methylation. npmC was synthesized and its expression in Escherichia coli resulted in a high level of resistance to 4,5-disubstituted 2-deoxystreptamine (2-DOS) and 4-monosubstituted 2-DOS aminoglycosides, as well as moderate resistance to 4,6-disusbstituted 2-DOS aminoglycosides, including the last resort aminoglycoside, plazomicin. Methylation at residue A1408 was confirmed by mass spectrometry assays. Analysis of the npmC gene background revealed that its genetic context was associated with different insertion sequences that could mobilise the gene. Similarities in the genetic context between npmC and npmA indicate that they share a common ancestor. The immediate genetic context of this methyltransferase indicates a high relationship to the Eubacteriales order. This finding reveals the dark matter of the microbiome as a potential source of novel resistance genes, expands the list of the true pan-aminoglycoside 16S rRNA methyltransferases, which threaten the usefulness and development of next-generation aminoglycosides.
{"title":"NpmC – a novel A1408 16S rRNA methyltransferase in the gut of humans and animals","authors":"Bosco R. Matamoros , Carlos Serna , Emilia Wedel , Natalia Montero , Finn Kirpekar , Bruno Gonzalez-Zorn","doi":"10.1016/j.ijantimicag.2024.107382","DOIUrl":"10.1016/j.ijantimicag.2024.107382","url":null,"abstract":"<div><div>NpmA and NpmB are 16S rRNA methyltransferases that act on residue A1408 and confer high-level resistance to almost all aminoglycosides; however, these methyltransferases are rarely reported. A novel gene, <em>npmC</em>, was identified after analysisng all world-wide available metagenomic projects in a One Health context. This gene has a high level of similarity (91.5%) with <em>npmA</em> and up to 92.7% similarity at amino acidic level. The protein encoded by this gene presents the conserved motifs required for A1408 methylation. <em>npmC</em> was synthesized and its expression in Escherichia coli resulted in a high level of resistance to 4,5-disubstituted 2-deoxystreptamine (2-DOS) and 4-monosubstituted 2-DOS aminoglycosides, as well as moderate resistance to 4,6-disusbstituted 2-DOS aminoglycosides, including the last resort aminoglycoside, plazomicin. Methylation at residue A1408 was confirmed by mass spectrometry assays. Analysis of the <em>npmC</em> gene background revealed that its genetic context was associated with different insertion sequences that could mobilise the gene. Similarities in the genetic context between <em>npmC</em> and <em>npmA</em> indicate that they share a common ancestor. The immediate genetic context of this methyltransferase indicates a high relationship to the Eubacteriales order. This finding reveals the dark matter of the microbiome as a potential source of novel resistance genes, expands the list of the true pan-aminoglycoside 16S rRNA methyltransferases, which threaten the usefulness and development of next-generation aminoglycosides.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107382"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107390
Lei Xu , Xiaoyu Lu , Yan Li , Patrick Butaye , Shangshang Qin , Zhiqiang Wang , Ruichao Li
Objectives
Tigecycline, a last-resort antibiotic in the tetracycline class, has been effective in treating infections caused by multidrug-resistant bacteria. However, the emergence of the tigecycline resistance gene cluster tmexCD-toprJ, which encodes a resistance-nodulation-division efflux pump, has significantly limited its therapeutic effectiveness. This study aims to explore the potential of CRISPR/Cas9-based plasmids to target and cleave tmexCD-toprJ gene cluster from bacterial plasmids and chromosomal integrative conjugative elements (ICEs), respectively.
Methods
We developed two CRISPR/Cas9-based plasmids, pCas9Kill and pCas9KillTS. The pCas9Kill plasmid designed to eliminate tmexCD-toprJ from plasmids through electroporation, while the pCas9KillTS plasmid, delivered through conjugation, targeted tmexCD-toprJ within ICEs on the bacterial chromosome. The plasmid modifications were assessed using nanopore long-read sequencing.
Results
Electroporation with the pCas9Kill plasmid resulted in the removal of tmexCD-toprJ from plasmids, restoring bacterial susceptibility to tigecycline. Nanopore sequencing revealed that the plasmids were repaired by insertion sequences after tmexCD-toprJ removal. In contrast, the pCas9KillTS plasmid introduced via conjugation to target tmexCD-toprJ gene cluster on ICEs within the chromosome. This approach led to chromosomal cleavage and subsequent bacterial cell death.
Conclusion
Our results demonstrate that both plasmids effectively inactivated tmexCD-toprJ, with pCas9Kill restoring tigecycline susceptibility in plasmid-bearing strains and pCas9KillTS causing targeted cell death in chromosomal ICE-harbouring bacteria. This study highlights the potential of CRISPR/Cas9 systems in addressing antibiotic resistance, providing a promising strategy to combat tigecycline-resistant pathogens.
{"title":"Eliminating the tigecycline resistance RND efflux pump gene cluster tmexCD-toprJ in bacteria using CRISPR/Cas9","authors":"Lei Xu , Xiaoyu Lu , Yan Li , Patrick Butaye , Shangshang Qin , Zhiqiang Wang , Ruichao Li","doi":"10.1016/j.ijantimicag.2024.107390","DOIUrl":"10.1016/j.ijantimicag.2024.107390","url":null,"abstract":"<div><h3>Objectives</h3><div>Tigecycline, a last-resort antibiotic in the tetracycline class, has been effective in treating infections caused by multidrug-resistant bacteria. However, the emergence of the tigecycline resistance gene cluster <em>tmexCD-toprJ</em>, which encodes a resistance-nodulation-division efflux pump, has significantly limited its therapeutic effectiveness. This study aims to explore the potential of CRISPR/Cas9-based plasmids to target and cleave <em>tmexCD-toprJ</em> gene cluster from bacterial plasmids and chromosomal integrative conjugative elements (ICEs), respectively.</div></div><div><h3>Methods</h3><div>We developed two CRISPR/Cas9-based plasmids, pCas9Kill and pCas9KillTS. The pCas9Kill plasmid designed to eliminate <em>tmexCD-toprJ</em> from plasmids through electroporation, while the pCas9KillTS plasmid, delivered through conjugation, targeted tmexCD-toprJ within ICEs on the bacterial chromosome. The plasmid modifications were assessed using nanopore long-read sequencing.</div></div><div><h3>Results</h3><div>Electroporation with the pCas9Kill plasmid resulted in the removal of tmexCD-toprJ from plasmids, restoring bacterial susceptibility to tigecycline. Nanopore sequencing revealed that the plasmids were repaired by insertion sequences after <em>tmexCD-toprJ</em> removal. In contrast, the pCas9KillTS plasmid introduced via conjugation to target <em>tmexCD-toprJ</em> gene cluster on ICEs within the chromosome. This approach led to chromosomal cleavage and subsequent bacterial cell death.</div></div><div><h3>Conclusion</h3><div>Our results demonstrate that both plasmids effectively inactivated <em>tmexCD-toprJ</em>, with pCas9Kill restoring tigecycline susceptibility in plasmid-bearing strains and pCas9KillTS causing targeted cell death in chromosomal ICE-harbouring bacteria. This study highlights the potential of CRISPR/Cas9 systems in addressing antibiotic resistance, providing a promising strategy to combat tigecycline-resistant pathogens.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107390"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijantimicag.2024.107394
Amaury O'Jeanson , Konstantinos Ioannidis , Elisabet I. Nielsen , Lamprini Galani , Aghavni Ginosyan , Harry Paskalis , Irena Loryan , Helen Giamarellou , Lena E. Friberg , Ilias Karaiskos
Purpose
To investigate the pharmacokinetics (PK) of ceftazidime-avibactam (CAZ-AVI) in critically ill patients undergoing continuous venovenous hemodiafiltration (CVVHDF), and compare with a general phase III trial population.
Methods
A prospective PK study was conducted in critically ill patients who received CVVHDF for acute kidney injury, treated with CAZ-AVI (1000/250 mg or 2000/500 mg q8h). Plasma and CVVHDF-circuit samples were collected to determine CAZ-AVI concentrations. Individual PK parameters at steady-state were estimated using non-compartmental analysis. For visual comparison, plasma concentrations from CVVHDF patients were overlaid with simulated data from patients not receiving CVVHDF based on previously developed population PK models.
Results
A total of 35 plasma samples and 16 CVVHDF-circuit samples were obtained from four patients, with two patients sampled on two separate occasions. Median total clearance and volume of distribution were 4.54 L/h and 73.2 L for CAZ and 10.5 L/h and 102 L for AVI, respectively. Median contribution of CVVHDF to total clearance was 19.8% for CAZ and 5.3% for AVI. Observed CAZ-AVI PK profiles were generally within the 90% confidence interval of model predictions, but the observed concentrations were notably lower early (0–2 h) and higher later (4–8 h) in the dosing interval, suggesting a higher volume of distribution.
Conclusions
These results suggest that the CAZ-AVI dose regimens used in this study can be applicable in critically ill patients undergoing CVVHDF, despite the different shape of the PK profiles observed in this population. Further research with a larger patient cohort is warranted to validate and refine these findings.
{"title":"Ceftazidime-avibactam (CAZ-AVI) pharmacokinetics in critically ill patients undergoing continuous venovenous hemodiafiltration (CVVHDF)","authors":"Amaury O'Jeanson , Konstantinos Ioannidis , Elisabet I. Nielsen , Lamprini Galani , Aghavni Ginosyan , Harry Paskalis , Irena Loryan , Helen Giamarellou , Lena E. Friberg , Ilias Karaiskos","doi":"10.1016/j.ijantimicag.2024.107394","DOIUrl":"10.1016/j.ijantimicag.2024.107394","url":null,"abstract":"<div><h3>Purpose</h3><div>To investigate the pharmacokinetics (PK) of ceftazidime-avibactam (CAZ-AVI) in critically ill patients undergoing continuous venovenous hemodiafiltration (CVVHDF), and compare with a general phase III trial population.</div></div><div><h3>Methods</h3><div>A prospective PK study was conducted in critically ill patients who received CVVHDF for acute kidney injury, treated with CAZ-AVI (1000/250 mg or 2000/500 mg q8h). Plasma and CVVHDF-circuit samples were collected to determine CAZ-AVI concentrations. Individual PK parameters at steady-state were estimated using non-compartmental analysis. For visual comparison, plasma concentrations from CVVHDF patients were overlaid with simulated data from patients not receiving CVVHDF based on previously developed population PK models.</div></div><div><h3>Results</h3><div>A total of 35 plasma samples and 16 CVVHDF-circuit samples were obtained from four patients, with two patients sampled on two separate occasions. Median total clearance and volume of distribution were 4.54 L/h and 73.2 L for CAZ and 10.5 L/h and 102 L for AVI, respectively. Median contribution of CVVHDF to total clearance was 19.8% for CAZ and 5.3% for AVI. Observed CAZ-AVI PK profiles were generally within the 90% confidence interval of model predictions, but the observed concentrations were notably lower early (0–2 h) and higher later (4–8 h) in the dosing interval, suggesting a higher volume of distribution.</div></div><div><h3>Conclusions</h3><div>These results suggest that the CAZ-AVI dose regimens used in this study can be applicable in critically ill patients undergoing CVVHDF, despite the different shape of the PK profiles observed in this population. Further research with a larger patient cohort is warranted to validate and refine these findings.</div></div>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"65 1","pages":"Article 107394"},"PeriodicalIF":4.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142710114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号