Objective To analyze the etiological characteristics,virulence genes and plasmids that carrying diarrhea-causing Proteus mirabilis and to assess their relationship with drug resistance and pathogenicity. Methods Proteus mirabilis coming from six different sources (food poisoning,external environment and healthy people) were analyzed biochemically,on related susceptibility and pulsed-field gel electrophoresis (PFGE). Virulence genes were detected by PCR. Plasmids were extracted and sequenced after gel electrophoresis purification. Results The biochemical characteristics of Proteus mirabilis from different sources seemed basically the same,and each of them showed having common virulence genes,as ureC,rsmA,hpmA and zapA. However,the PFGE patterns and susceptibility of these strains were different,so as the plasmids that they carried. Plasmid that presented in the sequenced strain showed that the 2 683 bp length plasmid encodes qnrD gene was associated with the quinolone resistance. Conclusion Etiological characteristics and molecular characteristics of Proteus mirabilis gathered from different sources,were analyzed. Results indicated that traditional biochemical analysis and common virulence gene identification might be able to distinguish the strains with different sources. However,PFGE and plasmids analysis could distinguish the sources of strains and to identify those plasmids that commonly carried by the drug-resistant strains. These findings also provided theoretical basis for further study on the nature of resistance and pathogenicity in Proteus mirabilis.

OBJECTIVETo understand the epidemiologic and etiologic characteristics of diarrheagenic Escherichia (E.) coli infections in Shenzhen.

METHODSStool samples were collected from acute diarrheal patients in four sentinel hospitals in Shenzhen and diarrheagenic E. coli strains were isolated and identified with multiplex real-time PCR. Serotyping and pulsed-field gel electrophoresis (PFGE) typing were conducted for the diarrheagenic E. coli isolates.

RESULTSA total of 74 diarrheagenic E. coli strains were isolated from 1 823 stool samples (4.06%). The patients were mainly young children aged <3 years and adults aged 20-39 years, and the infections mainly occurred during May-September of a year. Enterotoxigenic E. coli (ETEC) and enteropathognic E. coli (EPEC) were predominant (45.9% and 31.1%). Serogroups and PFGE patterns varied among the diarrheagenic E. coli isolates. However, serogroup O159 were predominant in ETEC and there were 5 clusters with ≥2 strains sharing same PFGE patterns.

CONCLUSIONSETEC and EPEC were predominant in diarrheagenic E. coli strains isolated from diarrheal patients in Shenzhen. Age and season specific characteristics of diarrheagenic E. coli infections were observed. The serotypes and PFGE patterns of diarrheagenic E. coli strains varied. Close attention should be paid to the possible ETEC outbreak.

Adult ; Child, Preschool ; China ; epidemiology ; Diarrhea ; epidemiology ; microbiology ; Disease Outbreaks ; Electrophoresis, Gel, Pulsed-Field ; Enterotoxigenic Escherichia coli ; classification ; isolation & purification ; Escherichia coli Infections ; epidemiology ; Humans ; Real-Time Polymerase Chain Reaction ; Serotyping ; Young Adult

OBJECTIVETo analyze the etiological characteristics, virulence genes and plasmids that carrying diarrhea-causing Proteus mirabilis and to assess their relationship with drug resistance and pathogenicity.

METHODSProteus mirabilis coming from six different sources (food poisoning, external environment and healthy people) were analyzed biochemically, on related susceptibility and pulsed-field gel electrophoresis (PFGE). Virulence genes were detected by PCR. Plasmids were extracted and sequenced after gel electrophoresis purification.

RESULTSThe biochemical characteristics of Proteus mirabilis from different sources seemed basically the same, and each of them showed having common virulence genes, as ureC, rsmA, hpmA and zapA. However, the PFGE patterns and susceptibility of these strains were different, so as the plasmids that they carried. Plasmid that presented in the sequenced strain showed that the 2 683 bp length plasmid encodes qnrD gene was associated with the quinolone resistance.

CONCLUSIONEtiological characteristics and molecular characteristics of Proteus mirabilis gathered from different sources, were analyzed. Results indicated that traditional biochemical analysis and common virulence gene identification might be able to distinguish the strains with different sources. However, PFGE and plasmids analysis could distinguish the sources of strains and to identify those plasmids that commonly carried by the drug-resistant strains. These findings also provided theoretical basis for further study on the nature of resistance and pathogenicity in Proteus mirabilis.

Diarrhea ; microbiology ; Drug Resistance, Bacterial ; Genes, Bacterial ; Humans ; Plasmids ; genetics ; Proteus mirabilis ; genetics ; pathogenicity ; Virulence Factors ; genetics