Abstract

WEILER, Natalie et al. Bacterial genetic profiles and analysis of outbreaks of foodborne diseases using pulsed field gel electrophoresis as a tool for molecular epidemiological surveillance. Mem. Inst. Investig. Cienc. Salud [online]. 2018, vol.16, n.2, pp.65-78. ISSN 1812-9528.  https://doi.org/10.18004/mem.iics/1812-9528/2018.016(02)65-078.

Foodborne diseases (FBD) are a problem of public health with high indexes of morbidity and mortality at global level. The surveillance and study of outbreaks of the FBD through pulsed field gel electrophoresis (PFGE) is a fundamental support for epidemiological research. The aim of the study is to present the database of bacterial genetic profiles and analyze outbreaks of FBD using PFGE. This was an observational descriptive retrospective study with convenience sampling in which 778 bacterial isolates causing FBD were studied. The National Database (NDB) was made up of the following enteric pathogens causing FBD: Salmonella spp., Shigella sonnei, Vibrio cholerae, Campylobacter spp., Escherichia coli O157: H7 and Escherichia coli no O157. Each of them was characterized by a diversity of unique patterns, clusters and outbreaks. The NDB of Salmonella spp. was represented by a total of 558 strains with 248 PUN, of which 22.6% (126 strains) correspond to Salmonella enterica ser. Typhimurium, 20.6% (115 strains) to Salmonella enterica ser. Enteritidis, 9.1% (51 strains) to Salmonella enterica ser. Newport, 1.6% (9 strains) to Salmonella enterica ser. Muenchen, which at the same time are the serotypes associated with outbreaks. A total of thirteen outbreaks caused by Salmonella spp., Shigella sonnei with 113 strains studied, 57 unique patterns and 19 clusters detected were confirmed. Three patterns PYJ16X01.0012, PYJ16X01.0034 and PYJ16X01.0014 were identified as the predominant. Vibrio cholerae with 18 strains studied, 9 unique patterns and 4 clusters were detected. A genetic relationship of 100% was established between strains of Vibrio cholerae O1 biotype El Tor serotype Ogawa toxin producer ctxA and tcpA isolated from the index case of the cholera outbreak. Campylobacter spp., with 62 strains studied, 42 unique patterns and 10 clusters were detected. The NDB of O157 and non-O157 Shiga toxin producing E. coli O157, with 9 and 20 strains of human origin respectively, were characterized according to their virulence factors and subtypes. We recognized 8 PUN electrophoretic patterns and 1 cluster for O157 Shiga toxin producing E. coli, and 18 PUN and 1 cluster for non-O157 Shiga toxin producing E. coli. The availability of a National Database of bacterial pathogens transmitted by food constitutes an important advance for public health, with a great contribution to the surveillance and epidemiology of the country allowing the confirmation and detection of outbreaks discriminating genetically related isolates and therefore, the study of clonal relationships and probable origin.

Keywords : foodborne diseases; pulsed field gel electrophoresis; molecular epidemiology.

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