Pub Date : 2023-06-26DOI: 10.3390/applmicrobiol3030044
Ghazal Shineh, M. Mobaraki, Mohammad Jabed Perves Bappy, D. Mills
Biofilm formation can lead to problems in healthcare, water distribution systems, food processing and packaging, industrial manufacturing, marine industries, and sanitation. These microbial communities can proliferate on biotic or abiotic surfaces, and are responsible for human disease and decreasing production efficiency and service equipment life in many industrial fields. The formation of biofilm starts with the attachment of bacteria to the surface, followed by bacterial proliferation and maturation of the microbial community. After forming a biofilm, bacteria not resistant to antimicrobial agents in their planktonic forms can turn resistant. The antibiotic resistance of bacterial biofilm, and the association of biofilms in generating infectious diseases in humans, highlight the need for designing novel and successful antibacterial, anti-biofilm, or anti-infection materials. This paper aims to review the mechanism of biofilm formation, the impact on different industries, the interaction mechanism of nanoparticles with bacteria, and strategies to design anti-biofilm materials. Examples of designing anti-infection bio-implants, coatings, medical devices, wound dressings, and sutures are reviewed.
{"title":"Biofilm Formation, and Related Impacts on Healthcare, Food Processing and Packaging, Industrial Manufacturing, Marine Industries, and Sanitation–A Review","authors":"Ghazal Shineh, M. Mobaraki, Mohammad Jabed Perves Bappy, D. Mills","doi":"10.3390/applmicrobiol3030044","DOIUrl":"https://doi.org/10.3390/applmicrobiol3030044","url":null,"abstract":"Biofilm formation can lead to problems in healthcare, water distribution systems, food processing and packaging, industrial manufacturing, marine industries, and sanitation. These microbial communities can proliferate on biotic or abiotic surfaces, and are responsible for human disease and decreasing production efficiency and service equipment life in many industrial fields. The formation of biofilm starts with the attachment of bacteria to the surface, followed by bacterial proliferation and maturation of the microbial community. After forming a biofilm, bacteria not resistant to antimicrobial agents in their planktonic forms can turn resistant. The antibiotic resistance of bacterial biofilm, and the association of biofilms in generating infectious diseases in humans, highlight the need for designing novel and successful antibacterial, anti-biofilm, or anti-infection materials. This paper aims to review the mechanism of biofilm formation, the impact on different industries, the interaction mechanism of nanoparticles with bacteria, and strategies to design anti-biofilm materials. Examples of designing anti-infection bio-implants, coatings, medical devices, wound dressings, and sutures are reviewed.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"175 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83447316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-25DOI: 10.3390/applmicrobiol3030043
M. Konaklieva, B. Plotkin
β-Lactams in the last thirty years have been viewed as universal acylating agents of serine and cysteine enzymes of both prokaryotic and eukaryotic systems. More recently, their use has been propelled by the COVID-19 pandemic, thus broadening their application as inhibitors of viral enzymes. The urea-based drugs have been extensively studied as inhibitors of the aforementioned enzymes. The focus of this review is the last decade’s drug discovery strategies, as well as new strategies that show utility in the expansion of β-lactams and ureas in the development of new antimicrobial and antiviral drugs.
{"title":"β-Lactams and Ureas as Cross Inhibitors of Prokaryotic Systems","authors":"M. Konaklieva, B. Plotkin","doi":"10.3390/applmicrobiol3030043","DOIUrl":"https://doi.org/10.3390/applmicrobiol3030043","url":null,"abstract":"β-Lactams in the last thirty years have been viewed as universal acylating agents of serine and cysteine enzymes of both prokaryotic and eukaryotic systems. More recently, their use has been propelled by the COVID-19 pandemic, thus broadening their application as inhibitors of viral enzymes. The urea-based drugs have been extensively studied as inhibitors of the aforementioned enzymes. The focus of this review is the last decade’s drug discovery strategies, as well as new strategies that show utility in the expansion of β-lactams and ureas in the development of new antimicrobial and antiviral drugs.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77784187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-21DOI: 10.3390/applmicrobiol3030042
E. El-Sawy, G. Kirsch, Mohamed Abdel-Aziz
Asteltoxins belong to a group of polyene pyrone mycotoxins that are known to be potent inhibitors of mitochondrial ATP synthesis and ATP hydrolysis. Asteltoxin A was first isolated from the toxic maize cultures of Aspergillus stellatus. Several attempts have been made to synthesize asteltoxin A, starting with the synthesis of a bis(tetrahydrofuran) moiety that has been demonstrated previously in biosynthetic studies. This review highlights the fungal sources of asteltoxins, similar asteltoxins, biosynthetic pathways, their synthetic trials, and their biological activities. This review is the first of its kind covering the periods from 1979 to 2023.
{"title":"Asteltoxins: Synthesis and Biological Studies","authors":"E. El-Sawy, G. Kirsch, Mohamed Abdel-Aziz","doi":"10.3390/applmicrobiol3030042","DOIUrl":"https://doi.org/10.3390/applmicrobiol3030042","url":null,"abstract":"Asteltoxins belong to a group of polyene pyrone mycotoxins that are known to be potent inhibitors of mitochondrial ATP synthesis and ATP hydrolysis. Asteltoxin A was first isolated from the toxic maize cultures of Aspergillus stellatus. Several attempts have been made to synthesize asteltoxin A, starting with the synthesis of a bis(tetrahydrofuran) moiety that has been demonstrated previously in biosynthetic studies. This review highlights the fungal sources of asteltoxins, similar asteltoxins, biosynthetic pathways, their synthetic trials, and their biological activities. This review is the first of its kind covering the periods from 1979 to 2023.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81248272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-18DOI: 10.3390/applmicrobiol3020041
Sheareazade A. Pena, Juan G. Salas, Nilisha Gautam, Ashley M. Ramos, A. Frantz
The production and consumer use of disinfectants has substantially increased during the COVID-19 pandemic. Benzalkonium chloride (BAC) is a mixture of alkyl benzyl dimethyl ammonium chloride compounds and is the most common active ingredient in surface cleaning and disinfecting products. Accordingly, BAC compounds are routinely in contact with microorganisms in indoor environments, which may contribute to the development of antimicrobial tolerance and cross-resistance. To investigate the impact of BAC exposure on commensal and opportunistic bacteria of public health importance, we exposed Staphylococcus epidermidis, Corynebacterium xerosis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa to a standard BAC mixture (BAC12–14), as well as purified BAC16. Minimum inhibitory concentrations (MICs) and antibiotic susceptibilities were determined before and after repeated exposure to sublethal BAC concentrations. MICs for Gram-negative bacteria were significantly higher than Gram-positive bacteria. Additionally, BAC12–14 MICs were significantly higher for opportunistic pathogens and BAC-tolerance was associated with antibiotic cross-resistance. These results suggest that common Gram-negative opportunistic pathogens are less sensitive to BAC-inhibition than commensal species and may preferentially develop antimicrobial tolerance upon repeated or prolonged exposure to BAC12–14. Reevaluating the formulation and concentration of BAC-containing products in efforts to limit the development of antimicrobial tolerance and antibiotic co-resistance is warranted.
{"title":"Sublethal Exposure to Common Benzalkonium Chloride Leads to Antimicrobial Tolerance and Antibiotic Cross-Resistance in Commensal and Opportunistic Bacterial Species","authors":"Sheareazade A. Pena, Juan G. Salas, Nilisha Gautam, Ashley M. Ramos, A. Frantz","doi":"10.3390/applmicrobiol3020041","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020041","url":null,"abstract":"The production and consumer use of disinfectants has substantially increased during the COVID-19 pandemic. Benzalkonium chloride (BAC) is a mixture of alkyl benzyl dimethyl ammonium chloride compounds and is the most common active ingredient in surface cleaning and disinfecting products. Accordingly, BAC compounds are routinely in contact with microorganisms in indoor environments, which may contribute to the development of antimicrobial tolerance and cross-resistance. To investigate the impact of BAC exposure on commensal and opportunistic bacteria of public health importance, we exposed Staphylococcus epidermidis, Corynebacterium xerosis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa to a standard BAC mixture (BAC12–14), as well as purified BAC16. Minimum inhibitory concentrations (MICs) and antibiotic susceptibilities were determined before and after repeated exposure to sublethal BAC concentrations. MICs for Gram-negative bacteria were significantly higher than Gram-positive bacteria. Additionally, BAC12–14 MICs were significantly higher for opportunistic pathogens and BAC-tolerance was associated with antibiotic cross-resistance. These results suggest that common Gram-negative opportunistic pathogens are less sensitive to BAC-inhibition than commensal species and may preferentially develop antimicrobial tolerance upon repeated or prolonged exposure to BAC12–14. Reevaluating the formulation and concentration of BAC-containing products in efforts to limit the development of antimicrobial tolerance and antibiotic co-resistance is warranted.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74846728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-15DOI: 10.3390/applmicrobiol3020040
T. Martins, L. Machado-Carvalho, A. Aires, M. Saavedra, G. Marques
Macrofungi have been previously studied for their nutritional value and medicinal properties. However, despite wild mushrooms being a great source of beneficial bioactive compounds, the literature exploring their biotechnological application as nutraceuticals, cosmeceuticals and nutricosmetics is scarce. In this work, the species Butyriboletus regius, Ganoderma lucidum, Inonotus hispidus, Lanmaoa fragrans, Pisolithus tinctorius, Suillellus luridus, Suillellus mendax and Xerocomus subtomentosus were characterized according to their phenolic composition, antioxidant capacity, antimicrobial activity and cosmeceutical potential. For that purpose, dried and ground mushrooms were extracted with ethanol (40% v/v) using ultrasound-assisted extraction. Of the eight mushrooms analyzed, I. hispidus and P. tinctorius stood out for their high content of phenolic compounds, high antioxidant capacity and anti-hyaluronidase activity. Regarding antimicrobial activity, both mushrooms showed good inhibition of bacterial growth and bactericidal activity, especially on Gram-positive bacteria; however, L. fragans obtained the best results. Cream formulations with I. hispidus and P. tinctorius extracts in their composition improved their antioxidant activity. These results indicate that I. hispidus and P. tinctorius can be proposed as a new potential source of natural compounds with application in the cosmetic industry.
{"title":"Antioxidant, Antimicrobial and Cosmeceutical Potential of Wild Mushroom Extracts","authors":"T. Martins, L. Machado-Carvalho, A. Aires, M. Saavedra, G. Marques","doi":"10.3390/applmicrobiol3020040","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020040","url":null,"abstract":"Macrofungi have been previously studied for their nutritional value and medicinal properties. However, despite wild mushrooms being a great source of beneficial bioactive compounds, the literature exploring their biotechnological application as nutraceuticals, cosmeceuticals and nutricosmetics is scarce. In this work, the species Butyriboletus regius, Ganoderma lucidum, Inonotus hispidus, Lanmaoa fragrans, Pisolithus tinctorius, Suillellus luridus, Suillellus mendax and Xerocomus subtomentosus were characterized according to their phenolic composition, antioxidant capacity, antimicrobial activity and cosmeceutical potential. For that purpose, dried and ground mushrooms were extracted with ethanol (40% v/v) using ultrasound-assisted extraction. Of the eight mushrooms analyzed, I. hispidus and P. tinctorius stood out for their high content of phenolic compounds, high antioxidant capacity and anti-hyaluronidase activity. Regarding antimicrobial activity, both mushrooms showed good inhibition of bacterial growth and bactericidal activity, especially on Gram-positive bacteria; however, L. fragans obtained the best results. Cream formulations with I. hispidus and P. tinctorius extracts in their composition improved their antioxidant activity. These results indicate that I. hispidus and P. tinctorius can be proposed as a new potential source of natural compounds with application in the cosmetic industry.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82489160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-06DOI: 10.3390/applmicrobiol3020039
Bahgat Z Gerges, J. Rosenblatt, Ying Jiang, I. Raad
Aims: We evaluated a novel disinfectant (VR) and seven comparators (disinfectants A–G) against resistant pathogens common in healthcare settings. Methods and Results: VR at different dilutions, along with commercial disinfectants A–G, was tested against surrogate viruses, and resistant bacterial and fungal pathogens. Surrogate viruses had an initial concentration of ~1 × 108 mL−1, and bacterial and fungal isolates had an initial concentration of ~1 × 106 mL−1 on Siliconee surfaces. After the application of VR or a comparator disinfectant, surfaces were tested for the reduction in microbial loads after 30 s and 5 min wet exposures, and after a 24 h dry residue exposure. Sterile deionized water was used as a control. The VR at a concentration of 4.68% was superior to all comparator disinfectants against most pathogens in wet and dry testing. The VR at 7.8% concentration showed the highest pathogen-reduction rate among all comparator disinfectants when tested against all pathogens. Conclusions: Overall, the novel VR disinfectant was the most effective disinfectant in both wet and dry residue states against the range of tested pathogens. Significance and Impact of the Study: VR is a broadly effective disinfectant combination for use in high-risk settings, particularly those in which intervals between applications of disinfectant can be lengthy or inconsistent.
{"title":"Comparative Effectiveness and Persistence of Antimicrobial Durability in Dry and Wet States of a Novel Antimicrobial Surface Disinfectant","authors":"Bahgat Z Gerges, J. Rosenblatt, Ying Jiang, I. Raad","doi":"10.3390/applmicrobiol3020039","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020039","url":null,"abstract":"Aims: We evaluated a novel disinfectant (VR) and seven comparators (disinfectants A–G) against resistant pathogens common in healthcare settings. Methods and Results: VR at different dilutions, along with commercial disinfectants A–G, was tested against surrogate viruses, and resistant bacterial and fungal pathogens. Surrogate viruses had an initial concentration of ~1 × 108 mL−1, and bacterial and fungal isolates had an initial concentration of ~1 × 106 mL−1 on Siliconee surfaces. After the application of VR or a comparator disinfectant, surfaces were tested for the reduction in microbial loads after 30 s and 5 min wet exposures, and after a 24 h dry residue exposure. Sterile deionized water was used as a control. The VR at a concentration of 4.68% was superior to all comparator disinfectants against most pathogens in wet and dry testing. The VR at 7.8% concentration showed the highest pathogen-reduction rate among all comparator disinfectants when tested against all pathogens. Conclusions: Overall, the novel VR disinfectant was the most effective disinfectant in both wet and dry residue states against the range of tested pathogens. Significance and Impact of the Study: VR is a broadly effective disinfectant combination for use in high-risk settings, particularly those in which intervals between applications of disinfectant can be lengthy or inconsistent.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78335192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-06DOI: 10.3390/applmicrobiol3020038
A. Ramos, A. Frantz
The use of conventional chemical disinfectants is a common practice in built environments and has drastically increased in response to the COVID-19 pandemic. While effective for instantaneous disinfection, the application of chemical disinfectants to indoor surfaces is associated with recontamination and is prone to select for antimicrobial-resistant pathogens. In contrast, probiotic-based sanitation (PBS) relies on the premise that probiotic bacteria, namely apathogenic Bacillus spp., when combined with eco-friendly detergents and applied to indoor surfaces can outcompete and exclude pathogens. Recent in situ studies assessing PBS in healthcare settings have demonstrated overwhelmingly positive results, including significant reductions in pathogen burden, antimicrobial-resistant genes and nosocomial infections, yet these studies are limited in duration and scope. Here, we review results of Bacillus-based PBS in practice, identify knowledge gaps and discuss the considerations for the widespread use of PBS in built environments. In a time when indoor cleaning and disinfection has come to the forefront, PBS may offer an attractive, effective and sustainable alternative to conventional chemical disinfectants.
{"title":"Probiotic-Based Sanitation in the Built Environment—An Alternative to Chemical Disinfectants","authors":"A. Ramos, A. Frantz","doi":"10.3390/applmicrobiol3020038","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020038","url":null,"abstract":"The use of conventional chemical disinfectants is a common practice in built environments and has drastically increased in response to the COVID-19 pandemic. While effective for instantaneous disinfection, the application of chemical disinfectants to indoor surfaces is associated with recontamination and is prone to select for antimicrobial-resistant pathogens. In contrast, probiotic-based sanitation (PBS) relies on the premise that probiotic bacteria, namely apathogenic Bacillus spp., when combined with eco-friendly detergents and applied to indoor surfaces can outcompete and exclude pathogens. Recent in situ studies assessing PBS in healthcare settings have demonstrated overwhelmingly positive results, including significant reductions in pathogen burden, antimicrobial-resistant genes and nosocomial infections, yet these studies are limited in duration and scope. Here, we review results of Bacillus-based PBS in practice, identify knowledge gaps and discuss the considerations for the widespread use of PBS in built environments. In a time when indoor cleaning and disinfection has come to the forefront, PBS may offer an attractive, effective and sustainable alternative to conventional chemical disinfectants.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89581757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-02DOI: 10.3390/applmicrobiol3020037
A. Marchesi, M. E. Nader-Macías
Probiotic formula for the vaginal tract must contain high numbers of viable beneficial bacteria that maintain their characteristics during the production and further storage, in order to exert the claimed probiotic effect. Four probiotic strains—Lactobacillus gasseri CRL1320, Limosilactobacillus reuteri CRL1324, Ligilactobacillus salivarius CRL1328 and Lacticaseibacillus rhamnosus CRL1332—originally isolated from vagina of healthy women exhibiting beneficial properties were evaluated. Therefore, the optimization of growth parameters and dry biomass production with high viability while preserving probiotic features of strains is a great challenge. Different growth conditions in MRS medium were set up in a laboratory bioreactor; two initial pH and agitation were recorded speeds during static or controlled fermentations. Production conditions of 37 °C with controlled pH 6.5 and 5.5-MRS with 150 and 75 rpm stirring speeds were used for CRL1329 and CRL1332 strains, respectively, while static and free pH MRS for CRL1324 and CRL1328 probiotics allowed us to obtain maximal cell viability counts. However, during 12 h of fermentation, biomass yields of 19.3, 16.2 and 15.2 g/L were achieved when CRL1329, CRL1328 and CRL1324 probiotic strains were grown in static and free pH MRS. The highest biomass yield for CRL1332 strain was produced under controlled MRS-initial pH 6.5 and 75 rpm fermentation conditions. To preserve probiotic high biomass viability, freeze-drying was carried out in the presence of different cryoprotective agents. Thus, the highest viable numbers (10.9–11.8 log CFU/g) with survival rates between 91.3 and 95.6% were attained in the presence of 10% trehalose (L. reuteri and L. salivarius), lactose (L. rhammosus) and lactose + trehalose + sucrose mix (L. gasseri). When stability during post-freeze-drying storage was evaluated, probiotic strains showed a remarkably higher viability recovery when stored at 4 °C than at 25 °C for 12 and 3 months, respectively. In addition, surface characteristics of vaginal probiotics were affected to different extents during storage depending on the strain, protective agent and storage time/temperature. Critical factors for growth conditions, drying process and storage stability of probiotic lactobacilli strains were optimized in view to preserve cell high viability and surface features for the design of vaginal probiotic formula.
{"title":"Probiotic Lactic Acid Bacteria for Vaginal Application. Optimization of Biomass Production and Freeze-Drying Conditions","authors":"A. Marchesi, M. E. Nader-Macías","doi":"10.3390/applmicrobiol3020037","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020037","url":null,"abstract":"Probiotic formula for the vaginal tract must contain high numbers of viable beneficial bacteria that maintain their characteristics during the production and further storage, in order to exert the claimed probiotic effect. Four probiotic strains—Lactobacillus gasseri CRL1320, Limosilactobacillus reuteri CRL1324, Ligilactobacillus salivarius CRL1328 and Lacticaseibacillus rhamnosus CRL1332—originally isolated from vagina of healthy women exhibiting beneficial properties were evaluated. Therefore, the optimization of growth parameters and dry biomass production with high viability while preserving probiotic features of strains is a great challenge. Different growth conditions in MRS medium were set up in a laboratory bioreactor; two initial pH and agitation were recorded speeds during static or controlled fermentations. Production conditions of 37 °C with controlled pH 6.5 and 5.5-MRS with 150 and 75 rpm stirring speeds were used for CRL1329 and CRL1332 strains, respectively, while static and free pH MRS for CRL1324 and CRL1328 probiotics allowed us to obtain maximal cell viability counts. However, during 12 h of fermentation, biomass yields of 19.3, 16.2 and 15.2 g/L were achieved when CRL1329, CRL1328 and CRL1324 probiotic strains were grown in static and free pH MRS. The highest biomass yield for CRL1332 strain was produced under controlled MRS-initial pH 6.5 and 75 rpm fermentation conditions. To preserve probiotic high biomass viability, freeze-drying was carried out in the presence of different cryoprotective agents. Thus, the highest viable numbers (10.9–11.8 log CFU/g) with survival rates between 91.3 and 95.6% were attained in the presence of 10% trehalose (L. reuteri and L. salivarius), lactose (L. rhammosus) and lactose + trehalose + sucrose mix (L. gasseri). When stability during post-freeze-drying storage was evaluated, probiotic strains showed a remarkably higher viability recovery when stored at 4 °C than at 25 °C for 12 and 3 months, respectively. In addition, surface characteristics of vaginal probiotics were affected to different extents during storage depending on the strain, protective agent and storage time/temperature. Critical factors for growth conditions, drying process and storage stability of probiotic lactobacilli strains were optimized in view to preserve cell high viability and surface features for the design of vaginal probiotic formula.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73108767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-30DOI: 10.3390/applmicrobiol3020036
M. Stocker, Jaclyn E. Smith, Y. Pachepsky
Irrigation waters may facilitate the spread of antibiotic-resistant bacteria or genes to humans and animals. Monitoring of resistance in irrigated waters has become common; however, many studies do not incorporate a spatial component into sampling designs. The objective of this work was to assess spatiotemporal variations in tetracycline-resistant E. coli in an irrigation pond. Water samples were collected at 10 locations and two different water depths, and in situ and laboratory water quality measurements were performed. The percentage of E. coli resistant to the low (4 μg mL−1) and high (16 μg mL−1) tetracycline doses varied by date and location but were observed to be as high as 12.7% and 6.3% of the total population throughout the study, respectively. While significant differences were not observed between resistance levels measured at different depths, on one date resistant E. coli were only detected in samples collected at depth. Nitrate, fluorescent dissolved organic matter, and dissolved oxygen concentrations were found to be the leading control variables for the percentage of resistant E. coli. This work demonstrates that there may be substantial spatial variability in concentrations of antibiotic-resistant E. coli in irrigation ponds which should be accounted for in the design of monitoring programs.
{"title":"Spatial Variation of Tetracycline-Resistant E. coli and Relationships with Water Quality Variables in Irrigation Water: A Pilot Study","authors":"M. Stocker, Jaclyn E. Smith, Y. Pachepsky","doi":"10.3390/applmicrobiol3020036","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020036","url":null,"abstract":"Irrigation waters may facilitate the spread of antibiotic-resistant bacteria or genes to humans and animals. Monitoring of resistance in irrigated waters has become common; however, many studies do not incorporate a spatial component into sampling designs. The objective of this work was to assess spatiotemporal variations in tetracycline-resistant E. coli in an irrigation pond. Water samples were collected at 10 locations and two different water depths, and in situ and laboratory water quality measurements were performed. The percentage of E. coli resistant to the low (4 μg mL−1) and high (16 μg mL−1) tetracycline doses varied by date and location but were observed to be as high as 12.7% and 6.3% of the total population throughout the study, respectively. While significant differences were not observed between resistance levels measured at different depths, on one date resistant E. coli were only detected in samples collected at depth. Nitrate, fluorescent dissolved organic matter, and dissolved oxygen concentrations were found to be the leading control variables for the percentage of resistant E. coli. This work demonstrates that there may be substantial spatial variability in concentrations of antibiotic-resistant E. coli in irrigation ponds which should be accounted for in the design of monitoring programs.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82542632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-25DOI: 10.3390/applmicrobiol3020035
Haruki Sawada, H. Tomita, Fumiyoshi Okazaki, Y. Tamaru
Methane (CH4) has attracted attention as not only one of the hydrogen carriers in terms of energy density, but also synthetic natural gas. In nature, the decomposition of organic compounds is performed with bacterial ecosystems that can produce CH4. Clostridium cellulovorans as a decomposer was cultivated with pig manure (PM) as an unused biomass in this study. As a result of high-performance liquid chromatography (HPLC) analysis, while formate and lactate were decreased in the C. cellulovorans medium containing 0.5% PM, acetate and butyrate were increased in it. Accordingly, in order to compare with the effect of carbon sources for methane production, the cocultivation of C. cellulovorans and the methanogenesis of Methanosarcina mazei or microbial flora of methane production (MFMP) was carried out in the C. cellulovorans medium. As a result, only the cocultivation with C. cellulovorans and MFMP showed methane production in 0.5% acetate medium. Moreover, in comparison with a carbon source in either 1% acetate or 1% methanol medium, MFMP was only cultivated after being precultivated with 0.5% glucose medium for 12 h. The results revealed that MFMP with a 1% methanol medium produced methane approximately eight times higher than with 1% acetate medium. After cultivation with 1% acetate or 1% methanol, next-generation sequencing (NGS) analysis of MFMP was carried out. Interestingly, Methanofollis (0.211%), belonging to methanogens through the CO2 reduction pathway, was dominant in the 1% acetate medium for 72 h cultivation, while Methanosarcina siciliae (1.178%), M. barkeri (0.571%), and Methanofollis (0.490%) were major species in 1% methanol medium for 72 h cultivation. Since Methanosarcina spp. belong to acetoclasts (acetoclastic pathway), methanol could promote the growth of Methanosarcina spp., rather than acetate. Therefore, it seems that Methanosarcina spp. may play a key methanogenesis role in MFMP. Thus, these results will provide important information for low-cost biomethane production.
{"title":"Comparison of Different Carbon Sources on Biomethane Production with Clostridium cellulovorans and Methanogens","authors":"Haruki Sawada, H. Tomita, Fumiyoshi Okazaki, Y. Tamaru","doi":"10.3390/applmicrobiol3020035","DOIUrl":"https://doi.org/10.3390/applmicrobiol3020035","url":null,"abstract":"Methane (CH4) has attracted attention as not only one of the hydrogen carriers in terms of energy density, but also synthetic natural gas. In nature, the decomposition of organic compounds is performed with bacterial ecosystems that can produce CH4. Clostridium cellulovorans as a decomposer was cultivated with pig manure (PM) as an unused biomass in this study. As a result of high-performance liquid chromatography (HPLC) analysis, while formate and lactate were decreased in the C. cellulovorans medium containing 0.5% PM, acetate and butyrate were increased in it. Accordingly, in order to compare with the effect of carbon sources for methane production, the cocultivation of C. cellulovorans and the methanogenesis of Methanosarcina mazei or microbial flora of methane production (MFMP) was carried out in the C. cellulovorans medium. As a result, only the cocultivation with C. cellulovorans and MFMP showed methane production in 0.5% acetate medium. Moreover, in comparison with a carbon source in either 1% acetate or 1% methanol medium, MFMP was only cultivated after being precultivated with 0.5% glucose medium for 12 h. The results revealed that MFMP with a 1% methanol medium produced methane approximately eight times higher than with 1% acetate medium. After cultivation with 1% acetate or 1% methanol, next-generation sequencing (NGS) analysis of MFMP was carried out. Interestingly, Methanofollis (0.211%), belonging to methanogens through the CO2 reduction pathway, was dominant in the 1% acetate medium for 72 h cultivation, while Methanosarcina siciliae (1.178%), M. barkeri (0.571%), and Methanofollis (0.490%) were major species in 1% methanol medium for 72 h cultivation. Since Methanosarcina spp. belong to acetoclasts (acetoclastic pathway), methanol could promote the growth of Methanosarcina spp., rather than acetate. Therefore, it seems that Methanosarcina spp. may play a key methanogenesis role in MFMP. Thus, these results will provide important information for low-cost biomethane production.","PeriodicalId":8080,"journal":{"name":"Applied microbiology","volume":"13 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77376423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}