Biocide tolerance in Salmonella from meats in Southern Spain

Salmonella serovars sampled from meat products in Southern Spain (Andalucía) during the period 2002-2007 were analyzed in this study. The serovars most frequently detected (in order) were Typhimurium, Enteritidis, Derby, Anatum and Rissen. Isolates (n = 43) were tested for sensitivity to biocides, including the quaternary ammonium compounds benzalkonium chloride (BC), cetrimide (CT) and hexadecylpyridinium chloride (HDP), and the bisphenols triclosan (TC) and hexachlorophene (CF). The minimum inhibitory concentration (MIC) for the quaternary ammonium compounds was in the range of 25 to 50 mg/L for most isolates, although a few isolates required much higher concentrations, up to 250 mg/L. Bisphenols showed higher inhibitory activity, with a MIC of 2.5 to 25 mg/L. A few isolates showed a “non-wildtype” MIC for TC of up to 250 mg/L. These results indicate a low incidence of tolerance towards quaternary ammonium compounds and triclosan among Salmonella from meats and meat products.

Application of a multiplex PCR assay for Campylobacter fetus detection and subspecies differentiation in uncultured samples of aborted bovine fetuses

Campylobacter (C.) fetus (epsilonproteobacteria) is an important veterinary pathogen. This species is currently divided into C. fetus subspecies (subsp.) fetus (Cff) and C. fetus subsp. venerealis (Cfv). Cfv is the causative agent of bovine genital Campylobacteriosis, an infectious disease that leads to severe reproductive problems in cattle worldwide. Cff is a more general pathogen that causes reproductive problems mainly in sheep although cattle can also be affected. Here we describe a multiplex PCR method to detect C. fetus and differentiate between subspecies in a single step. The assay was standardized using cultured strains and successfully used to analyze the abomasal liquid of aborted bovine fetuses without any pre-enrichment step. Results of our assay were completely consistent with those of traditional bacteriological diagnostic methods. Furthermore, the multiplex PCR technique we developed may be easily adopted by any molecular diagnostic laboratory as a complementary tool for detecting C. fetus subspecies and obtaining epidemiological information about abortion events in cattle.