Nontyphoid Salmonella gastroenteritis in pediatric patients from urban areas in the city of Mérida, Venezuela.
BACKGROUND
Nontyphoid Salmonella (NTS) infections are a frequent cause of self-limited diarrhoeal illness in healthy children that do not usually require antibiotic treatment. This study was conducted by analyzing the phenotypic and genotypic traits of NTS strains from pediatric patients with acute gastroenteritis living in urban areas in the city of Mérida, Venezuela.


METHODS
Thirty-seven Salmonella strains (18 S. Enteritidis; 14 S. Typhimurium; 2 S. Java; 2 S. Saintpaul; 1 S. Infantis) were isolated from 243 stool specimens. These strains were biochemically identified and serotyped. Antimicrobial susceptibility was determined by the disc-diffusion assay. Genetic characterization included plasmid profiling, PCR detection of the spv region and inv genes, and IS200 typing.


RESULTS
Thirty (81.0%) of the Salmonella isolates were resistant to the antimicrobial tested. Of these strains, 17 (56.7%) were resistant to at least one antibiotic. Five resistance patterns were observed, of which the most frequently found was the single type (tetracycline, streptomycin or ampicillin). All the S. Typhimurium harbored plasmids, but only three large plasmids (60, 72 and 84 kb) yielded amplicons with a spvR specific primers. All the Salmonella serotypes showed the presence of an inv region. Eight distinct IS200 profiles could be detected among the 37 Salmonella strains studied.


CONCLUSIONS
Predominant Enteritidis and Typhimurium serotypes, as well as serotypes Java, Saintpaul and Infantis, are circulating in the city of Mérida, Venezuela. Most of these strains are susceptible to first-line antibiotics but active monitoring of isolates for antimicrobial resistance is necessary. IS200 typing, applied in association with conventional methods, allowed the characterization of all isolates and suggested the presence of different infection sources.
Araque
María
M
Laboratorio de Microbiología Molecular, Departamento de Microbiología y Parasitología, Facultad de Farmacia y Bioanálisis, Universidad de Los Andes, Mérida, Venezuela. araquemc@ula.ve
D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002675:Child, Preschool; D004251:DNA Transposable Elements / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D012477:Salmonella enteritidis / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D012486:Salmonella typhimurium / Q000145:classification / Q000187:drug effects / Q000235:genetics; D012703:Serotyping; D014157:Transcription Factors / Q000235:genetics; D014505:Urban Population; D014687:Venezuela / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D014157:Transcription Factors; C061928:mkaC protein, Salmonella typhimurium; C075518:invA protein, Bacteria