Eduardo de Freitas Costa

Neosporose bovina: avaliação da transmissão vertical e fração atribuível de aborto em uma população de bovinos no Estado do Rio Grande do Sul

The protozoa Nesporora caninum is a parasite that causes great economic and reproductive losses in cattle worldwide. The objective of this study was to verify the association between abortion and the presence of antibodies against N. caninum and the vertical transmission as a means of maintaining the infection in cattle herds in Rio Grande do Sul by matching the serology of mothers and daughters. Sampling was performed in 60 dairy farms of two regions of the state, where blood was collected from 40% of the herds for the detection of anti-N. caninum by indirect immunofluorescence (IFI). To verify the association between abortion and seropositivity we used the univariate logistic regression test, and for the serology of mothers and daughters the chi-square McNemar test for paired data. In comparing serology and abortion data, a prevalence of 58.5% (24/41) among cattle with history of abortion, and 16.4% (199/1215) prevalence between those with no history of abortion was found; seropositive animals were 7.21 times more likely (95% CI, 3.65-14.32) to have previously aborted (Wald statistic χ 2=44.93, P<0.001). The fraction affected by neosporosis in the population studied was estimated as 9.73% (λpop). The serologic result of each mother was paired with her daughter and showed by the McNemar chi-square (χ2=59.84, P<0.001) significant association between the serology of mothers and daughters, suggesting vertical transmission. It is worth to note the importance of serological monitoring for N. caninu to avoid maintenance of animals that may serve as carries of the parasite reservoir on the farms.

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates collected from diseased food-producing animals in the GERM-Vet monitoring program 2008-2014.

The aim of this study was to identify extended-spectrum β-lactamase (ESBL)-producing Escherichia coli collected from diseased food-producing animals in Germany. A total of 6849 E. coli isolates, collected from diseased cattle, pigs and poultry in the German national monitoring program GERM-Vet (2008-2014), were characterized by antimicrobial susceptibility testing and screened for the ESBL phenotype. ESBL genes were identified by PCR and sequencing. The isolates were further characterized by PCR-based phylotyping. The 419/6849 (6.1%) ESBL-producers identified included 324/2896 (11.2%) isolates from cattle, 75/1562 (4.8%) from pigs and 20/2391 (0.8%) from poultry. The ESBL genes detected were: blaCTX-M-1 (69.9%), blaCTX-M-15 (13.6%), blaCTX-M-14 (11.7%), blaTEM-52 (1.9%), blaSHV-12 (1.4%), blaCTX-M-3 (1.0%), and blaCTX-M-2 (0.5%). The phylogroup A was the dominant phylogroup (57.0%) followed by phylogroups D (23.4%), B1 (17.9%), and B2 (1.7%). Bovine isolates belonged predominantly to the phylogroups A and D, whereas the porcine and avian isolates mainly belonged to A and B1. The majority of the ESBL-producing isolates found in each phylogroup were from animals suffering from gastrointestinal infections. In 399/419 isolates (95.2%), additional resistance to non-β-lactam antibiotics was seen. Multidrug-resistance [resistance to aminoglycosides, fluoro(quinolones), sulphonamides, tetracyclines, and trimethoprim] was seen in 369/419 (88.1%) isolates, which may facilitate the co-selection of ESBL genes, when located on the same mobile genetic element as the others resistance genes, and may compromise the therapeutic options.

Effect of slaughterhouse and day of sample on the probability of a pig carcass being Salmonella-positive according to the Enterobacteriaceae count in the largest Brazilian pork production region

Sources of contamination of carcasses during slaughter include infected pigs as well as environmentally related sources. There are many microbial indicators that can be used in the processing of food to assess food hygiene and the safety of food processing. The presence of some microbial indicators can be viewed as a result of direct or indirect contamination of a food with fecal material. The presence of Enterobacteriaceae is often used as a hygiene indicator, as they are found both in the environment and in the intestine of warm-blooded animals. An association between Salmonella isolation and Enterobacteriaceae count (EC) on pre-chill carcasses has been described, however the impact of slaughterhouse and the day of sampling on the occurrence of Salmonella has not been previously investigated. To this end, mixed logistic regressions (MLRs) with random effects and fixed slopes were performed to assess the change in EC and its correlation with Salmonella occurrence using two data sets. The first describes the EC and Salmonella isolation in 60 pork carcasses in one slaughterhouse sampled at 11 different slaughter steps, including the carcass as a random effect. The second describes the EC and Salmonella isolation on 1150 pre-chill carcasses sampled in 13 slaughterhouses over 230 sampling days, and the model combined two random intercepts, slaughterhouse and date of sampling nested with slaughterhouse (day/slaughterhouse). Statistically significant associations (p<0.0001) between the log of the EC and Salmonella occurrence were found in all models. Nevertheless, although a strong association was found between Enterobacteriaceae and Salmonella contamination in pork carcasses, this association was not constant, given that there was a high variation in the probability of a carcass being positive for Salmonella according to the EC mainly between days of samples. The effect of the day of sampling on Salmonella prevalence was so large that the predictive value of the EC count for Salmonella isolation on a daily basis was compromised. It is possible that on some days batches with a high prevalence of Salmonella carriers shedding a high number of Salmonella were slaughtered. On these days, the potential for contamination/cross-contamination of carcasses will be so large that even hygienic slaughter, confirmed by the low EC on carcasses, will not be able to prevent the presence of Salmonella on some carcasses. The results of this study demonstrate that, despite the statistically significant association found, it may be difficult to predict when hygiene failure measured via EC actually indicates Salmonella contamination, and neither the inverse.

A Stochastic Model to Assess the Effect of Meat Inspection Practices on the Contamination of the Pig Carcasses: A Stochastic Model to Assess the Effect of Meat Inspection Practices

The objective of meat inspection is to promote animal and public health by preventing, detecting, and controlling hazards originating from animals. With the improvements of sanitary level in pig herds, the hazards profile has shifted and the inspection procedures no longer target major foodborne pathogens (i.e., not risk based). Additionally, carcass manipulations performed when searching for macroscopic lesions can lead to cross-contamination. We therefore developed a stochastic model to quantitatively describe cross-contamination when consecutive carcasses are submitted to classic inspection procedures. The microbial hazard used to illustrate the model was Salmonella, the data set was obtained from Brazilian slaughterhouses, and some simplifying assumptions were made. The model predicted that due to cross-contamination during inspection, the prevalence of contaminated carcass surfaces increased from 1.2% to 95.7%, whereas the mean contamination on contaminated surfaces decreased from 1 logCFU/cm² to -0.87 logCFU/cm², and the standard deviations decreased from 0.65 to 0.19. These results are explained by the fact that, due to carcass manipulations with hands, knives, and hooks, including the cutting of contaminated lymph nodes, Salmonella is transferred to previously uncontaminated carcasses, but in small quantities. These small quantities can easily go undetected during sampling. Sensitivity analyses gave insight into the model performance and showed that the touching and cutting of lymph nodes during inspection can be an important source of carcass contamination. The model can serve as a tool to support discussions on the modernization of pig carcass inspection.