Prevalence, associated risk factors, and antimicrobial resistance profiles of non-typhoidal Salmonella in large scale swine production in Córdoba, Argentina.

Non-typhoidal Salmonella is considered a major public health concern. The growing relevance of pigs as reservoir of Salmonella spp. has prompted several countries to set up surveillance and control programs to fight Salmonella infection in swine and reduce public health risk. In the last decade, pork production in Córdoba increased significantly to become one of the most important pig production provinces in Argentina. The aim of this study was to estimate Salmonella spp. prevalence and associated risk factors in large scale-farms in this province. Mesenteric lymph nodes (MLN) of 580 pigs from 20 finishing large-scale farms were collected between 2014 and 2015 to estimate Salmonella infection. A prevalence of 41.5% (95%CI: 37.6-45.6%) was observed. Two major risk factors were significantly associated with Salmonella infection, both related to the pre-slaughter period (distance from the farm to the slaughterhouse and lairage time), highlighting the need to pay special attention to pre-slaughter practices in the province. Shortening transport times and complying with national regulations for lairage time at slaughter may help to reduce the prevalence of infection. Sixteen different serovars were identified, being S. Anatum and S. Typhimurium the most prevalent ones. Moreover, two isolate of the monophasic variant of Salmonella Typhimurium (I 4,5,12:i:-) resistant to enrofloxacin and which also displayed multidrug resistance was isolated for first time from pigs in Córdoba. The moderate to high levels of antimicrobial resistance detected for antibiotics commonly used in the pig sector suggested the need for implementing a plan to limit their use in the province.

Case-control study of risk factors for high within-flock small-ruminant brucellosis prevalence in a brucellosis low-prevalence area.

A case-control study was conducted in a brucellosis low-prevalence area of NW Spain to determine factors associated with high within-flock small-ruminant brucellosis prevalence in 1998. Forty-one cases and 69 controls were selected and information from both official sources and personal interviews was retrieved for every flock. The relationship between variables obtained and flock status was assessed by unconditional multivariable logistic regression analysis. The introduction of replacement animals into the flock, the presence of older farmers, an inadequate brucellosis vaccination programme and higher flock seroprevalence in the town in 1997 were positively associated with case flocks. Thus, specific actions directed at farms presenting these characteristics should be included within official eradication programmes. In addition, for the 1999 campaign the time from sampling to culling the seropositive animals correlated positively (r=0.53; P<0.01) with the flock seroprevalence the following year, suggesting the need for a faster removal of the infected animals to increase the efficacy of the eradication campaigns.