Through investigating ten recreational marine beaches in China, we aimed to detect the occurrence of human enteric viruses in coastal bathing beaches and find a correlationship, if any, between the presence of enteric...Through investigating ten recreational marine beaches in China, we aimed to detect the occurrence of human enteric viruses in coastal bathing beaches and find a correlationship, if any, between the presence of enteric viruses in surface seawater and the concentrations of fecal coliforms, the conventional indicator of fecal pollution. In this study, twenty seawater samples were assayed for fecal coliforms and human pathogenic enteric viruses （hepatitis A viruses, rotaviruses, polioviruses） analysis. Enteric viruses were detected by RT-PCR, in 20 sample sites, 5%, 40%, 40% were positive for the presence of human hepatitis A viruses, rotaviruses, polioviruses, respectively. Seven of 20 sites are suffering from severe fecal contamination, based on traditional plate counts of fecal coliform outnumbering the established thresholds for recreation. Additionally, statistical analysis presented that no correlation was found between bacterial indicators and viruses in surface seawaters. The data confirmed that indicator bacteria in water are not reflective of the presence of enteric viruses in marine waters. Thus, current recreational water quality standards of both bacterial and viral indices should be reevaluated.展开更多
Enterococcus faecalis isolates （87） were phenotypically and genotypically identified and subsequently subjected to the antagonism test and antimicrobial susceptibility. The lipolitic, hemolytic and DNAse activities ...Enterococcus faecalis isolates （87） were phenotypically and genotypically identified and subsequently subjected to the antagonism test and antimicrobial susceptibility. The lipolitic, hemolytic and DNAse activities were identified along with the genes gelE, cylL, cylS, ccf, cpd and cob that, encode virulence determinants. Thirty seven percent of isolates inhibited Listeria monocytogenes （CERELA）, Listeria innocuous （CERELA）, Staphylococcus aureus （ATCC25932）, Lactococcus lactis （IL1403）, Micrococcus luteus （ATCC 10240） and Enterococcusfaecalis （ATCC29212）. All strains were sensitive to the ampicillin antibiotic, but 47% were resistant to at least one antimicrobial agent and 6% of isolates presented multidrug resistance. Ninety seven percent of isolates contained the gelE gene, but 77% of these isolates showed gelatinase activity. Presence of cylL and cylS genes was observed in 25% of the isolates, but only 5% presented hemolytic activity. None isolates showed lipase and DNAse activities. Eight percent of isolates contained the ccf gene and 2% showed the presence of the cpd and cob genes. The ability to inhibit pathogenic bacteria, low resistance to antibiotics and absence of virulence factors make some of Enterococcusfaecalis strains characterized in the present study promising for exploitation in other applications such as probiotics in aquaculture.展开更多
Emerging and re-emerging viruses continue to surface all over the world.Some of these viruses have the potential for rapid and global spread with high morbidity and mortality,such as the SARS coronavirus outbreak.It i...Emerging and re-emerging viruses continue to surface all over the world.Some of these viruses have the potential for rapid and global spread with high morbidity and mortality,such as the SARS coronavirus outbreak.It is extremely urgent and important to identify a novel virus near-instantaneously to develop an active preventive and/or control strategy.As a cultureindependent approach,viral metagenomics has been widely used to investigate highly divergent and completely new viruses in humans,animals,and even environmental samples in the past decade.A new model of Koch's postulates,named the metagenomic Koch's postulates,has provided guidance for the study of the pathogenicity of novel viruses.This review explains the viral metagenomics strategy for virus discovery and describes viruses discovered in human feces in the past 10 years using this approach.This review also addresses issues related to the metagenomic Koch's postulates and the challenges for virus discovery in the future.展开更多
基金provided by the National High Technology Research and Development Program("863"Program)of China,grant no.2006AA09Z162the National Key Scientific and Technological Project,grant no.908-01-ZH3
文摘Through investigating ten recreational marine beaches in China, we aimed to detect the occurrence of human enteric viruses in coastal bathing beaches and find a correlationship, if any, between the presence of enteric viruses in surface seawater and the concentrations of fecal coliforms, the conventional indicator of fecal pollution. In this study, twenty seawater samples were assayed for fecal coliforms and human pathogenic enteric viruses （hepatitis A viruses, rotaviruses, polioviruses） analysis. Enteric viruses were detected by RT-PCR, in 20 sample sites, 5%, 40%, 40% were positive for the presence of human hepatitis A viruses, rotaviruses, polioviruses, respectively. Seven of 20 sites are suffering from severe fecal contamination, based on traditional plate counts of fecal coliform outnumbering the established thresholds for recreation. Additionally, statistical analysis presented that no correlation was found between bacterial indicators and viruses in surface seawaters. The data confirmed that indicator bacteria in water are not reflective of the presence of enteric viruses in marine waters. Thus, current recreational water quality standards of both bacterial and viral indices should be reevaluated.
文摘Enterococcus faecalis isolates （87） were phenotypically and genotypically identified and subsequently subjected to the antagonism test and antimicrobial susceptibility. The lipolitic, hemolytic and DNAse activities were identified along with the genes gelE, cylL, cylS, ccf, cpd and cob that, encode virulence determinants. Thirty seven percent of isolates inhibited Listeria monocytogenes （CERELA）, Listeria innocuous （CERELA）, Staphylococcus aureus （ATCC25932）, Lactococcus lactis （IL1403）, Micrococcus luteus （ATCC 10240） and Enterococcusfaecalis （ATCC29212）. All strains were sensitive to the ampicillin antibiotic, but 47% were resistant to at least one antimicrobial agent and 6% of isolates presented multidrug resistance. Ninety seven percent of isolates contained the gelE gene, but 77% of these isolates showed gelatinase activity. Presence of cylL and cylS genes was observed in 25% of the isolates, but only 5% presented hemolytic activity. None isolates showed lipase and DNAse activities. Eight percent of isolates contained the ccf gene and 2% showed the presence of the cpd and cob genes. The ability to inhibit pathogenic bacteria, low resistance to antibiotics and absence of virulence factors make some of Enterococcusfaecalis strains characterized in the present study promising for exploitation in other applications such as probiotics in aquaculture.
文摘Emerging and re-emerging viruses continue to surface all over the world.Some of these viruses have the potential for rapid and global spread with high morbidity and mortality,such as the SARS coronavirus outbreak.It is extremely urgent and important to identify a novel virus near-instantaneously to develop an active preventive and/or control strategy.As a cultureindependent approach,viral metagenomics has been widely used to investigate highly divergent and completely new viruses in humans,animals,and even environmental samples in the past decade.A new model of Koch's postulates,named the metagenomic Koch's postulates,has provided guidance for the study of the pathogenicity of novel viruses.This review explains the viral metagenomics strategy for virus discovery and describes viruses discovered in human feces in the past 10 years using this approach.This review also addresses issues related to the metagenomic Koch's postulates and the challenges for virus discovery in the future.
