This study was designed to investigate the molecular epidemiology of mobile colistin resistance(mcr)using a"One-Health"approach in Laos and to predict whether any dominant plasmid backbone and/or strain type...This study was designed to investigate the molecular epidemiology of mobile colistin resistance(mcr)using a"One-Health"approach in Laos and to predict whether any dominant plasmid backbone and/or strain type influences the dissemination of mcr.We collected 673 samples from humans(rectal normal flora),poultry,and the environment(water,flies,birds,etc.)in Vientiane,Lao People’s Democratic Republic(Laos),from May to September 2018.A total of 238 Escherichia coli(E.coli)isolated from nonduplicative samples,consisting of 98 MCR-positive E.coli(MCRPEC)("mcr"denotes the gene encoding mobile colistin resistance,and"MCR"denotes the subsequent protein encoded by mcr)and 140 MCRnegative E.coli(MCRNEC),were characterized by phenotype and Illumina sequencing.A subset of MCRPEC was selected for Min ION sequencing,conjugation assay,plasmid stability,and growth kinetics in vitro.The prevalence of MCRPEC was found to be 14.6%(98/673),with the highest prevalence in human rectal swabs(45.9%(45/98),p<0.0001,odds ratio(OR):0.125,95% confidence interval(CI):0.077-0.202).The percentages of MCRPEC from other samples were 14.3%(2/14)in dog feces,12.0%(24/200)in flies,11.0%(11/100)in chicken meat,8.9%(8/90)in chicken cloacal,8.0%(4/50)in chicken caeca,and 7.5%(4/53)in wastewater.MCRPEC was significantly more resistant to co-amoxiclav,sulfamethoxazoletrimethoprim,levofloxacin,ciprofloxacin,and gentamicin than MCRNEC(p<0.05).Genomic analysis revealed the distribution of MCRPEC among diverse clonal types.The putative plasmid Inc types associated with mcr-1 were Inc X4,Inc HI2,Inc P1,Inc I2,and Inc FIA,and those associated with mcr-3 were Inc FII,Inc FIA,Inc FIB,Inc P1,and Inc R.Recovery of highly similar plasmids from both flies and other sampling sectors implied the role of flies in the dissemination of mcr-1.mcr-positive plasmids were shown to be conjugative,and a significantly high transfer rate into a hypervirulent clone ST1193 was observed.Plasmids containing mcr irrespective of Inc type were highly stable and invariably did not exert a fitness effect upon introduction into a new host.These findings signify the urgent need for a standard infection control program to radically decontaminate the source of resistance.展开更多
Background:Burkholderia pseudomallei is a tropical pathogen that causes melioidosis.Its intrinsic drug-resistance is a leading cause of treatment failure,and the few available antibiotics require prolonged use to be e...Background:Burkholderia pseudomallei is a tropical pathogen that causes melioidosis.Its intrinsic drug-resistance is a leading cause of treatment failure,and the few available antibiotics require prolonged use to be effective.This study aimed to assess the clinical potential of B.pseudomallei phages isolated from Hainan,China.Methods:Burkholderia pseudomallei strain(HNBPoo1)was used as the isolation host,and phages were recovered from domestic environmental sources,which were submitted to the host range determination,lytic property assays,and stability tests.The best candidate was examined via the transmission electron microscope for classification.With its genome sequenced and analyzed,its protective efficacy against B.pseudomallei infection in A549 cells and Caenorhabditis elegans was evaluated,in which cell viability and survival rates were compared using the one-way ANOVA method and the log-rank test.Results:A phage able to lyse 24/25 clinical isolates was recovered.It was classified in the Podoviridae family and was found to be amenable to propagation.Under the optimal multiplicity of infection(MOl)of o.1,an eclipse period of around 20 min and a high titer(io12 PFU/ml)produced within 1 h were demonstrated.This phage was found stabile at a wide range of temperatures(24,37,40,50,and 60 C)and pH values(3-12).After being designated as vB_BpP_HN01,it was fully sequenced,and the 71,398 bp linear genome,containing 93 open reading frames and a tRNA-Asn,displayed a low sequence similarity with known viruses.Additionally,protective effects of applications of vB_BpP_HNo1(MOl=0.1 and MOl=1)alone or in combination with antibiotics were found to improve viability of infected cells(70.6±6.8%,85.8±5.7%,91.9±1.8%,and 96.8±1.8%,respectively).A significantly reduced mortality(10%)and a decreased pathogen load were demonstrated in infected C.elegans following the addition of this phage.Conclusions:As the frst B.pseudomallei phage was isolated in Hainan,China,phage vB_BpP_HNO1 was characterized by promising lytic property,stability,and effciency of bacterial elimination during the in vitro/vivo experiments.Therefore,we can conclude that it is a potential alternative agent for combating melioidosis.展开更多
基金funded partly by the Wellcome Trust(214207/Z/18/Z)。
文摘This study was designed to investigate the molecular epidemiology of mobile colistin resistance(mcr)using a"One-Health"approach in Laos and to predict whether any dominant plasmid backbone and/or strain type influences the dissemination of mcr.We collected 673 samples from humans(rectal normal flora),poultry,and the environment(water,flies,birds,etc.)in Vientiane,Lao People’s Democratic Republic(Laos),from May to September 2018.A total of 238 Escherichia coli(E.coli)isolated from nonduplicative samples,consisting of 98 MCR-positive E.coli(MCRPEC)("mcr"denotes the gene encoding mobile colistin resistance,and"MCR"denotes the subsequent protein encoded by mcr)and 140 MCRnegative E.coli(MCRNEC),were characterized by phenotype and Illumina sequencing.A subset of MCRPEC was selected for Min ION sequencing,conjugation assay,plasmid stability,and growth kinetics in vitro.The prevalence of MCRPEC was found to be 14.6%(98/673),with the highest prevalence in human rectal swabs(45.9%(45/98),p<0.0001,odds ratio(OR):0.125,95% confidence interval(CI):0.077-0.202).The percentages of MCRPEC from other samples were 14.3%(2/14)in dog feces,12.0%(24/200)in flies,11.0%(11/100)in chicken meat,8.9%(8/90)in chicken cloacal,8.0%(4/50)in chicken caeca,and 7.5%(4/53)in wastewater.MCRPEC was significantly more resistant to co-amoxiclav,sulfamethoxazoletrimethoprim,levofloxacin,ciprofloxacin,and gentamicin than MCRNEC(p<0.05).Genomic analysis revealed the distribution of MCRPEC among diverse clonal types.The putative plasmid Inc types associated with mcr-1 were Inc X4,Inc HI2,Inc P1,Inc I2,and Inc FIA,and those associated with mcr-3 were Inc FII,Inc FIA,Inc FIB,Inc P1,and Inc R.Recovery of highly similar plasmids from both flies and other sampling sectors implied the role of flies in the dissemination of mcr-1.mcr-positive plasmids were shown to be conjugative,and a significantly high transfer rate into a hypervirulent clone ST1193 was observed.Plasmids containing mcr irrespective of Inc type were highly stable and invariably did not exert a fitness effect upon introduction into a new host.These findings signify the urgent need for a standard infection control program to radically decontaminate the source of resistance.
文摘Background:Burkholderia pseudomallei is a tropical pathogen that causes melioidosis.Its intrinsic drug-resistance is a leading cause of treatment failure,and the few available antibiotics require prolonged use to be effective.This study aimed to assess the clinical potential of B.pseudomallei phages isolated from Hainan,China.Methods:Burkholderia pseudomallei strain(HNBPoo1)was used as the isolation host,and phages were recovered from domestic environmental sources,which were submitted to the host range determination,lytic property assays,and stability tests.The best candidate was examined via the transmission electron microscope for classification.With its genome sequenced and analyzed,its protective efficacy against B.pseudomallei infection in A549 cells and Caenorhabditis elegans was evaluated,in which cell viability and survival rates were compared using the one-way ANOVA method and the log-rank test.Results:A phage able to lyse 24/25 clinical isolates was recovered.It was classified in the Podoviridae family and was found to be amenable to propagation.Under the optimal multiplicity of infection(MOl)of o.1,an eclipse period of around 20 min and a high titer(io12 PFU/ml)produced within 1 h were demonstrated.This phage was found stabile at a wide range of temperatures(24,37,40,50,and 60 C)and pH values(3-12).After being designated as vB_BpP_HN01,it was fully sequenced,and the 71,398 bp linear genome,containing 93 open reading frames and a tRNA-Asn,displayed a low sequence similarity with known viruses.Additionally,protective effects of applications of vB_BpP_HNo1(MOl=0.1 and MOl=1)alone or in combination with antibiotics were found to improve viability of infected cells(70.6±6.8%,85.8±5.7%,91.9±1.8%,and 96.8±1.8%,respectively).A significantly reduced mortality(10%)and a decreased pathogen load were demonstrated in infected C.elegans following the addition of this phage.Conclusions:As the frst B.pseudomallei phage was isolated in Hainan,China,phage vB_BpP_HNO1 was characterized by promising lytic property,stability,and effciency of bacterial elimination during the in vitro/vivo experiments.Therefore,we can conclude that it is a potential alternative agent for combating melioidosis.
