Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived fo...Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived foods such as raw poultry and pork.This study aimed to characterize the genetic diversity,plasmid replicon types,and antibiotic resistance of 15 S.1,4,[5],12:i:-environmental isolates collected from two poultry farms using pulsed-field gel electrophoresis(PFGE),multilocus sequence typing(MLST),polymerase chain reaction-based replicon typing,and minimum inhibitory concentration approach.Ten different PFGE genotypes were detected,indicating a high diversity among these S.1,4,[5],12:i:-isolates.Three sequence types(ST19,ST1544,ST34)were identified by MLST.Among them,ST1544 was first detected in S.1,4,[5],12:i:-environmental isolates from poultry farms.All isolates were resistant to cefazolin,cefotetan,tobramycin,amikacin,and gentamicin,but susceptible to piperacillin-tazobactam,aztreonam,ceftazidime,cefepime,and ertapenem.Five incompatibility groups(Inc)of plasmids were identified,including IncFIIs(66.7%),IncHI2(20%),IncI1(6.7%),IncN(6.7%),and IncQ(6.7%).Among these isolates,80%carried at least one plasmid replicon type,and 20%carried multiple plasmid replicon types.Interestingly,the multidrug-resistant isolate 263 carried numerous resistance genes(i.e.qnrS,aac(6ʹ)-Ib-cr,bla_(TEM),bla_(CTX-M-9),bla_(OXA-1),sul1,sul2,sul3,floR,and mcr-1)and class I integronase gene intI1,which possessed both IncHI2 and IncQ plasmids,suggesting that resistance genes may be horizontally transferred by the combination of IncHI2 and IncQ plasmids.Collectively,antibiotic-resistant S.1,4,[5],12:i:-isolates were first found in poultry farm environments in China,and surveillance should be strengthened to prevent their further spread from poultry farms to foods.展开更多
An outbreak associated with Streptococcus suis infection in humans emerged in Sichuan province, China in 2005. The outbreak is atypical for the apparent large number of human cases, high fatality rate and geographical...An outbreak associated with Streptococcus suis infection in humans emerged in Sichuan province, China in 2005. The outbreak is atypical for the apparent large number of human cases, high fatality rate and geographical spread. To determine whether the bacterium has changed, we compared both human and animal isolates from the Sichuan outbreak with those collected previously within China and in other countries using whole genome PCR scanning (WGPScaning) comparative sequencing of several known virulence factor genes and multilocus sequence typing (MLST) analysis. WGPScanning analysis showed that all primer pairs yielded PCR products of the expected sizes in all four strains tested. The nucleotide sequences of all the detected virulence factor genes are identical in the four strains and MLST results showed that the four isolates studied and reference strain all belonged to the ST1 com-plex. No new genetic changes were found in the genome structure of the isolates from this Sichuan outbreak.展开更多
Farm products are considered important vehicles for the transmission of Listeria monocytogenes(L.monocytogenes).The typing of L.monocytogenes from farm products contributes to the surveillance and source tracing of th...Farm products are considered important vehicles for the transmission of Listeria monocytogenes(L.monocytogenes).The typing of L.monocytogenes from farm products contributes to the surveillance and source tracing of the pathogen.In this study,77 L.monocytogenes strains from seven farm product categories in Shanghai were analyzed by serological typing,multilocus sequence typing(MLST),pulsed-field gel electrophoresis(PFGE),and whole-genome nucleotide polymorphism(wgSNP).The results showed that the 77 isolates were classified into four serovars(1/2a,1/2c,1/2b,and 4b),and of these,1/2a(n=47)was the most prevalent.Seventeen sequence types(STs)were generated by MLST with two novel STs(ST1402 and ST1403),and 20 of 77 L.monocytogenes isolates had high genetic identity with previously documented outbreak isolates according to the minimum spanning tree from the MLST results.Moreover,34 PFGE patterns(PF1-PF34)were differentiated,and based on a similarity value higher than 80%by the unweighted pair group method dendrogram,the discriminatory index was relatively low(equal to 0.775).Furthermore,14 isolates were chosen and further analyzed by wgsNP based on the previous typing results,which demonstrated that wgSNP and MLST yielded mostly consistent typing results but higher resolution than PFGE.In conclusion,77 L.monocytogenes isolates from farm products collected in nine districts in Shanghai were highly genetically diverse,and 20 of these isolates had high relatedness with previously documented outbreak strains worldwide.The results indicate a possible cross-contamination risk of L.monocytogenes and a potential public health concern resulting from farm products during the supply chain in Shanghai,China.展开更多
基金supported by the National Natural Science Foundation of China(No.32102111)the Project was funded by the China Postdoctoral Science Foundation(2021M702194).
文摘Salmonella enterica serovar 1,4,[5],12:i:-(S.1,4,[5],12:i:-)has been recognized as an emerging foodborne pathogen in recent years.It can cause human salmonellosis predominated by the contamination of animal-derived foods such as raw poultry and pork.This study aimed to characterize the genetic diversity,plasmid replicon types,and antibiotic resistance of 15 S.1,4,[5],12:i:-environmental isolates collected from two poultry farms using pulsed-field gel electrophoresis(PFGE),multilocus sequence typing(MLST),polymerase chain reaction-based replicon typing,and minimum inhibitory concentration approach.Ten different PFGE genotypes were detected,indicating a high diversity among these S.1,4,[5],12:i:-isolates.Three sequence types(ST19,ST1544,ST34)were identified by MLST.Among them,ST1544 was first detected in S.1,4,[5],12:i:-environmental isolates from poultry farms.All isolates were resistant to cefazolin,cefotetan,tobramycin,amikacin,and gentamicin,but susceptible to piperacillin-tazobactam,aztreonam,ceftazidime,cefepime,and ertapenem.Five incompatibility groups(Inc)of plasmids were identified,including IncFIIs(66.7%),IncHI2(20%),IncI1(6.7%),IncN(6.7%),and IncQ(6.7%).Among these isolates,80%carried at least one plasmid replicon type,and 20%carried multiple plasmid replicon types.Interestingly,the multidrug-resistant isolate 263 carried numerous resistance genes(i.e.qnrS,aac(6ʹ)-Ib-cr,bla_(TEM),bla_(CTX-M-9),bla_(OXA-1),sul1,sul2,sul3,floR,and mcr-1)and class I integronase gene intI1,which possessed both IncHI2 and IncQ plasmids,suggesting that resistance genes may be horizontally transferred by the combination of IncHI2 and IncQ plasmids.Collectively,antibiotic-resistant S.1,4,[5],12:i:-isolates were first found in poultry farm environments in China,and surveillance should be strengthened to prevent their further spread from poultry farms to foods.
基金Supported by the National Key Technologies Research and Development Program (Grant No. 2005BA711A09)from the Ministry of Science and Technology of China
文摘An outbreak associated with Streptococcus suis infection in humans emerged in Sichuan province, China in 2005. The outbreak is atypical for the apparent large number of human cases, high fatality rate and geographical spread. To determine whether the bacterium has changed, we compared both human and animal isolates from the Sichuan outbreak with those collected previously within China and in other countries using whole genome PCR scanning (WGPScaning) comparative sequencing of several known virulence factor genes and multilocus sequence typing (MLST) analysis. WGPScanning analysis showed that all primer pairs yielded PCR products of the expected sizes in all four strains tested. The nucleotide sequences of all the detected virulence factor genes are identical in the four strains and MLST results showed that the four isolates studied and reference strain all belonged to the ST1 com-plex. No new genetic changes were found in the genome structure of the isolates from this Sichuan outbreak.
基金funded by the Shanghai Agriculture Applied Technology Development Program of China (No.X20210302)the National Natural Science Foundation of China (No.31701714).
文摘Farm products are considered important vehicles for the transmission of Listeria monocytogenes(L.monocytogenes).The typing of L.monocytogenes from farm products contributes to the surveillance and source tracing of the pathogen.In this study,77 L.monocytogenes strains from seven farm product categories in Shanghai were analyzed by serological typing,multilocus sequence typing(MLST),pulsed-field gel electrophoresis(PFGE),and whole-genome nucleotide polymorphism(wgSNP).The results showed that the 77 isolates were classified into four serovars(1/2a,1/2c,1/2b,and 4b),and of these,1/2a(n=47)was the most prevalent.Seventeen sequence types(STs)were generated by MLST with two novel STs(ST1402 and ST1403),and 20 of 77 L.monocytogenes isolates had high genetic identity with previously documented outbreak isolates according to the minimum spanning tree from the MLST results.Moreover,34 PFGE patterns(PF1-PF34)were differentiated,and based on a similarity value higher than 80%by the unweighted pair group method dendrogram,the discriminatory index was relatively low(equal to 0.775).Furthermore,14 isolates were chosen and further analyzed by wgsNP based on the previous typing results,which demonstrated that wgSNP and MLST yielded mostly consistent typing results but higher resolution than PFGE.In conclusion,77 L.monocytogenes isolates from farm products collected in nine districts in Shanghai were highly genetically diverse,and 20 of these isolates had high relatedness with previously documented outbreak strains worldwide.The results indicate a possible cross-contamination risk of L.monocytogenes and a potential public health concern resulting from farm products during the supply chain in Shanghai,China.
