First detection of Salmonella spp. in backyard production farms from central Chile

Abstract

ObjectiveThe purpose of this study was to detect the presence of circulatingSalmonellaspp. on backyard production systems (BPS) with poultryor swine breeding in central ChileIntroductionCharacteristics and conditions of backyard production systems(BPS) transform them into potential maintainers of priority zoonoticagents, likeSalmonellaspp., highly important agent because of itsimpact in animal and public health (1).MethodsA stratified and proportional random sampling approach wasperformed (2), based on 15 provinces from the study area (regions ofValparaiso, Metropolitana and LGB O’Higgins). 329 BPS sampled(equivalent to 1,744 samples). Stool content inoculated in test tubeswith peptone water (APT, Difco®) supplemented with Novobiocin(Sigma®), incubated for 18 to 24 hours at 37° C. Subcultured onmodify semisolid Rappaport Vassiliadis (MSRV, Oxoid®) agarsupplemented with Novobiocin, incubated for 24 to 48 hours at 41.5° C.Samples compatible with growth and/or diffusion were sub-culturedby exhaustion on Xylose Lysine Deoxychocolate (XLD, Difco®) agarand then incubated for 24 hours at 37° C (3). Confirmation made byconventional PCR forinvAgenes (4). Serotypes were predicted usinga combination of PCR and sequencing, aimed directly at genes codingfor O, H1 and H2 antigens (5).Results1,744 samples were collected belonging to the 329 BPS. 15 positiveBPS (4.6%) detected. Serotypes detected correspond toSalmonellaTyphimurium (21.7%), followed bySalmonellaEnteritidis (13.0%)andSalmonellaInfantis (13.0%),SalmonellaHadar or Istanbul(8.7%),Salmonella[z42] or Tenessee (4.4%),SalmonellaKentucky(4.4) and unknown (34.8%) (Table 1).ConclusionsThis is the first evidence of serotypes ofSalmonellaspp. circulatingat a regional level in BPS from central Chile. A relevant pathogen forpublic health.