摘要：The aim of this work was to assess the level of microbial contamination and resistance of bacteria isolated from a highthroughput heavy pig slaughterhouse (approx. 4600 pigs/day) towards antimicrobials considered as critical for human, veterinary or both chemotherapies. Samples, pre-operative and operative, were obtained in 4 different surveys. These comprised environmental sampling,
i.e. air (n
total = 192) and surfaces (n
total = 32), in four different locations. Moreover, a total of 40 carcasses were sampled in two different moments of slaughtering following Reg. (CE) 2073/2005. Overall, 60 different colonies were randomly selected from VRBGA plates belonging to 20 species, 15 genera and 10 families being
Enterobacteriaceae,
Moraxellaceae and
Pseudomonadaceae the most represented ones. Thirty-seven isolates presented resistance to at least one molecule and seventeen were classified as multi-drug resistant.
Enterobacteriaceae, particularly
E. coli, displayed high MIC values towards trimethoprim, ampicillin, tetracycline and sulphametoxazole with MIC
max of 16, 32, 32 and 512 mg/L, respectively. Moreover, isolated
Pseudomonas spp. showed high MIC values in critical antibiotics such as ampicillin and azithromycin with MIC
max of 32 and 64 mg/L, respectively. Additionally,
in vitro biofilm formation assays demonstrated that fifteen of these isolates can be classified as strong biofilm formers. Results demonstrated that a high diversity of bacteria containing antibiotic resistant and multiresistant species is present in the sampled abattoir. Considering these findings, it could be hypothesised that the processing environment could be a potential diffusion determinant of antibiotic resistant bacteria through the food chain and operators.
