Phenotypic and genotypic antibiotic resistance patterns in Salmonella Typhimurium and its monophasic variant from pigs in southern Spain.

The high incidence of human salmonellosis and multi-drug resistant (MDR) strains of Salmonella Typhimurium (ST) is of concern to global public and animal health. Our research, by means of the broth microdilution method, evaluated the Minimum Inhibitory Concentration (MIC) distribution of 12 antimicrobials against a collection of 73 ST and mST and S. typhimurium monophasic variant 4,[5],12:i:- (mST) isolates from slaughtered pigs reared in extensive systems in southern Spain, and also 12 resistance-associated genes or antimicrobial resistance (AMR) determinants using qPCR. Our data revealed that 98.6% of strains were MDR, with resistance to cephalothin/tetracycline/sulfamethoxazole-trimethoprim/ampicillin/chloramphenicol being the most common pattern (55.6%). Regarding AMR determinants, the most significantly (p < 0.05) genes detected by qPCR were sul1 and aadA2 (89% of strains positive), aadA1 and dfrA12 (87.7%), and blaTEM and tet(B) (86.3% and 84.9%, respectively). Up to date information on ST antimicrobial resistance patterns is essential for epidemiological surveillance programs to support animal and public health. The high number of MDR isolates and variability regarding resistance determinants revealed in this study highlights the role of animals reared in extensive systems as a source of resistant Salmonella strains.

Survival of Streptococcus suis, Streptococcus dysgalactiae and Trueperella pyogenes in dry-cured Iberian pork shoulders and loins.

Dry-cured hams, shoulders and loins of Iberian pigs are highly appreciated in national and international markets. Salting, additive addition and dehydration are the main strategies to produce these ready-to-eat products. Although the dry curing process is known to reduce the load of well-known food borne pathogens, studies evaluating the viability of other microorganisms in contaminated pork have not been performed. In this work, the efficacy of the dry curing process to eliminate three swine pathogens associated with pork carcass condemnation, Streptococcus suis, Streptococcus dysgalactiae and Trueperella pyogenes, was evaluated. Results of this study highlight that the dry curing process is a suitable method to obtain safe ready-to-eat products free of these microorganisms. Although salting of dry-cured shoulders had a moderate bactericidal effect, results of this study suggest that drying and ripening were the most important stages to obtain dry-cured products free of these microorganisms.

Serosurvey on schmallenberg virus and selected ovine reproductive pathogens in culled ewes from southern Spain.

After the first case of Schmallenberg virus (SBV) was reported in southern Spain (March 2012), a retrospective serological study was carried out in extensive sheep flocks from nearby areas to assess the history of exposure to SBV and other selected ovine reproductive pathogens (Chlamydophila abortus, Coxiella burnetii, Border Disease virus 'BDV', Toxoplasma gondii and Neospora caninum). Secondly, the presence of antibodies was investigated in meat juice samples against selected pathogens to validate their use in serosurveys in sheep. A total of 209 Merina and cross-bred culled ewes belonging to 12 outdoor flocks managed in extensive breeding systems were sampled. Serum and meat juice samples were collected at the slaughterhouse and analysed using commercial ELISA kits. Chlamydophila abortus (62.68%, CI95 56.13-69.23) and Toxoplasma gondii (57.42%, CI95 50.72-64.12) were the most prevalent pathogens. The seroprevalence of BDV (16.27%, CI95 11.27-21.27) and Coxiella burnetii (13.88%, CI95 9.2-18.56) was moderate, and only 4 of 209 animals (1.91%, CI95 1.82-2.96) presented specific antibodies against Neospora caninum or SBV. All the examined ovine flocks were seropositive to three or more pathogens. The highest percentage of seropositive animals was detected for T. gondii-C. abortus coseropositive (25.36%) culled ewes. The concordance between serum and meat juice samples was moderate for T. gondii (κ = 0.419) and BDV (κ = 0.568), and fair for C. abortus (κ = 0.311). Our results show evidence of circulation of SBV from summer 2011 in southern Spain. Furthermore, C. abortus and T. gondii were the most prevalent pathogens associated with sheep in outdoor rearing systems. Finally, these preliminary results point to meat juice samples as a potential biological sample for serosurveys studies on sheep.