Introduction:Aeromonas is widely distributed in aquatic environments.This study describes the pathogenic characteristics of Aeromonas isolated from adult diarrhea patients and aquatic environments in Beijing,China.Met...Introduction:Aeromonas is widely distributed in aquatic environments.This study describes the pathogenic characteristics of Aeromonas isolated from adult diarrhea patients and aquatic environments in Beijing,China.Methods:Aeromonas isolates from patients with diarrhea and river water samples were assessed using whole-genome sequencing(WGS)and antibiotic resistance profiling.Results:In total,38 Aeromonas isolates were collected.Among these,13 isolates were from patients with common clinical symptoms,including diarrhea,abdominal pain,and nausea.Four of 13 Aeromonaspositive patients were co-infected with other intestinal pathogens.Patient-derived Aeromonas isolates showed high resistance to ampicillin,ampicillin-sulbactam,nalidixic acid,and tetracycline,whereas water-derived isolates showed high resistance to ampicillin,ampicillin-sulbactam,and nalidixic acid.Phylogenetic analysis revealed seven independent branches,without significant clustering among patient-and water-derived isolates.Conclusions:This study provides valuable insights into the prevalence and characteristics of Aeromonas.The intertwined distribution of patient-and waterderived isolates in the phylogenetic tree deserves attention.展开更多
Long-term and stable preservation of bacteriophages is of crucial importance.Although many efforts have been made in the past decades to explore the influence of external factors on bacteriophage preservation,there is...Long-term and stable preservation of bacteriophages is of crucial importance.Although many efforts have been made in the past decades to explore the influence of external factors on bacteriophage preservation,there is still little understanding,and a systematic description is lacking.In this study,we explored the influence of different factors on the preservation of lytic bacteriophage VP3,one of the typing bacteriophages of Vibrio cholerae O1 biotype El Tor,and attempted to optimize its preservation.We examined external factors,including temperature,solution,and cryoprotectant,in stable cooling/freezing conditions or alternate cooling/freezing and thawing.We found that whether in Luria-Bertani(LB)medium or SM buffer,in terms of 20-week stable cooling or freezing,−20℃ was the most damaging while 4℃,−80℃,and−196℃ were protective.Thirteen cycles of alternate cooling/freezing and thawing caused a loss in the survival rates of bacteriophages.The addition of cryoprotectant,glycerol(30%,w/v)or dimethyl sulfoxide(DMSO,10%,w/v)significantly improved the survival rates of bacteriophages preserved at−20℃.However,at 4℃,−80℃,and−196℃,the cryoprotectant effect was only slightly positive or even harmful.In summary,for bacteriophage VP3,the best preservation method is to directly preserve the bacteriophage stocks in LB medium at−80℃ or−196℃ instead of storing them in SM buffer or adding cryoprotectant.Our results provided insights into the external influencing factors on bacteriophage VP3 during preservation at low temperature and can be applied to the optimization of bacteriophage preservation in the future.展开更多
基金Supported by the National Key Research Program of China(2021YFF0703801).
文摘Introduction:Aeromonas is widely distributed in aquatic environments.This study describes the pathogenic characteristics of Aeromonas isolated from adult diarrhea patients and aquatic environments in Beijing,China.Methods:Aeromonas isolates from patients with diarrhea and river water samples were assessed using whole-genome sequencing(WGS)and antibiotic resistance profiling.Results:In total,38 Aeromonas isolates were collected.Among these,13 isolates were from patients with common clinical symptoms,including diarrhea,abdominal pain,and nausea.Four of 13 Aeromonaspositive patients were co-infected with other intestinal pathogens.Patient-derived Aeromonas isolates showed high resistance to ampicillin,ampicillin-sulbactam,nalidixic acid,and tetracycline,whereas water-derived isolates showed high resistance to ampicillin,ampicillin-sulbactam,and nalidixic acid.Phylogenetic analysis revealed seven independent branches,without significant clustering among patient-and water-derived isolates.Conclusions:This study provides valuable insights into the prevalence and characteristics of Aeromonas.The intertwined distribution of patient-and waterderived isolates in the phylogenetic tree deserves attention.
基金National Science and Technology Major Project on Important Infectious Diseases Prevention and Control(2018ZX10734404)National Science and Technology Infrastructure of China(National Pathogen Resource Center‐NPRC‐32)+1 种基金National Science and Technology Fundamental Resources Investigation Program of China(2021FY100904)National Nature Science Foundation of China(82161148010‐4,52076140).
文摘Long-term and stable preservation of bacteriophages is of crucial importance.Although many efforts have been made in the past decades to explore the influence of external factors on bacteriophage preservation,there is still little understanding,and a systematic description is lacking.In this study,we explored the influence of different factors on the preservation of lytic bacteriophage VP3,one of the typing bacteriophages of Vibrio cholerae O1 biotype El Tor,and attempted to optimize its preservation.We examined external factors,including temperature,solution,and cryoprotectant,in stable cooling/freezing conditions or alternate cooling/freezing and thawing.We found that whether in Luria-Bertani(LB)medium or SM buffer,in terms of 20-week stable cooling or freezing,−20℃ was the most damaging while 4℃,−80℃,and−196℃ were protective.Thirteen cycles of alternate cooling/freezing and thawing caused a loss in the survival rates of bacteriophages.The addition of cryoprotectant,glycerol(30%,w/v)or dimethyl sulfoxide(DMSO,10%,w/v)significantly improved the survival rates of bacteriophages preserved at−20℃.However,at 4℃,−80℃,and−196℃,the cryoprotectant effect was only slightly positive or even harmful.In summary,for bacteriophage VP3,the best preservation method is to directly preserve the bacteriophage stocks in LB medium at−80℃ or−196℃ instead of storing them in SM buffer or adding cryoprotectant.Our results provided insights into the external influencing factors on bacteriophage VP3 during preservation at low temperature and can be applied to the optimization of bacteriophage preservation in the future.
