ABSTRACT
In 2011, an outbreak of illness caused by Yersinia enterocolitica O:9 in Norway was linked to ready-to-eat salad mix, an unusual vehicle for this pathogen. The outbreak illustrates the need to characterize isolates of this organism, and reinforces the need for international traceback mechanisms for fresh produce.
Subject(s)
Disease Outbreaks , Food Microbiology , Yersinia Infections/epidemiology , Yersinia Infections/etiology , Yersinia enterocolitica , Adolescent , Adult , Bacterial Outer Membrane Proteins/genetics , Child , Female , Humans , Male , Middle Aged , Norway/epidemiology , Serotyping , Yersinia Infections/diagnosis , Yersinia enterocolitica/classification , Yersinia enterocolitica/genetics , Yersinia enterocolitica/isolation & purification , Young AdultSubject(s)
Escherichia coli Infections/diagnosis , Escherichia coli Infections/microbiology , Escherichia coli O157/isolation & purification , Shiga Toxin 1/genetics , Sorbitol/metabolism , Virulence Factors/genetics , Aged , Bacterial Typing Techniques , Fermentation , Humans , Male , Molecular Typing , NorwayABSTRACT
In the last three decades, high rates of resistance to common first-line antimicrobial agents have been reported in Salmonella enterica serotype Typhi (Typhi), the causative organism of typhoid fever (TF), in many regions of the world, especially in South East Asia. Analysis of Typhi strains isolated from outbreaks and sporadic cases of TF in Son La province, northwest Vietnam, in 2002 revealed that 94.5% (85/90) of the isolates were fully susceptible to amoxicillin, chloramphenicol, cotrimoxazole, tetracycline, and nalidixic acid. There was a clear decline in the occurrence of multi-drug resistant (MDR) Typhi isolates collected in this province in 2002 (4.4%) compared with the period 1995-1999 in the same province (30.8-100%). By using molecular (IS200 profiling, PstI-ribotyping, XbaI-pulsed-field gel electrophoresis, and haplotyping) and phage-typing methods, we showed that the Typhi isolates from Son La province in 2002 were genetically related; however, they were unrelated to the previous MDR clones established in Vietnam.
Subject(s)
Anti-Bacterial Agents/pharmacology , Salmonella typhi/drug effects , Salmonella typhi/genetics , Typhoid Fever/microbiology , Adolescent , Adult , Aged , Bacteriophage Typing , Child , Child, Preschool , DNA Transposable Elements/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Disease Outbreaks , Electrophoresis, Gel, Pulsed-Field , Female , Humans , Infant , Male , Middle Aged , Poverty , Ribotyping , Salmonella typhi/growth & development , Salmonella typhi/isolation & purification , Typhoid Fever/epidemiology , Vietnam/epidemiologyABSTRACT
A multiplex PCR assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic Escherichia coli and Shigella spp. The virulence genes selected for each category were Stx1, Stx2, and eaeA for enterohemorrhagic E. coli (EHEC), eaeA for enteropathogenic E. coli (EPEC), STIb and LTI for enterotoxigenic E. coli (ETEC), ipaH for enteroinvasive E. coli (EIEC) and Shigella spp., and aggR for enteroaggregative E. coli (EAEC). Each forward primer was labelled with a fluorochrome and the PCR products were separated by multicolour capillary electrophoresis on an ABI PRISM310 Genetic Analyzer (Applied Biosystems). If present, several gene variants of each virulence gene were identified. The internal control gene rrs, encoding 16S rRNA, was amplified in all 110 clinical strains analyzed. Virulence genes were demonstrated in 103 (94%) of these strains. In the majority of the cases (98/103, 95%), classification obtained by the novel multiplex PCR assay was in agreement with that previously determined by phenotypic assays combined with other molecular genetic approaches. Numerous multiplex PCR assays have been published, but only a few of them detect all five E. coli pathotypes within a single reaction, and none of them has used multicolour capillary electrophoresis to separate the PCR products. The octaplex PCR assay followed by capillary electrophoresis presented in the present paper provides a simple, reliable, and rapid procedure that in a single reaction identifies the five main pathotypes of E. coli, and Shigella spp. This assay will replace the previous molecular genetic methods used in our laboratory and work as an important supplement to the more time-consuming phenotypic assays.
