Characterization of microbial ecology, Listeria monocytogenes, and Salmonella sp. on equipment and utensil surfaces in Brazilian poultry, pork, and dairy industries.

This study aimed to evaluate the level of counting by indicator microorganisms, identify the microbial ecology, detect Listeria monocytogenes and Salmonella sp., and determine the presence of virulence genes and biofilm formation. A total of 480 samples were collected from the surfaces of the equipment and utensils using sterile swabs for the detection of L. monocytogenes and Salmonella sp. and counting mesophilic aerobes, Enterobacteriaceae, Escherichia coli, and Pseudomonas sp. The microbial ecology was evaluated by sequencing the 16S rRNA gene. Genes for virulence and biofilm formation were analyzed and adhesion capacity was evaluated for L. monocytogenes and Salmonella sp. The mesophilic aerobe count was the highest in the dairy processing facility, followed by the pork and poultry slaughterhouses. L. monocytogenes was detected in all facilities, with the highest detection in the pork slaughterhouse, followed by the poultry and dairy facilities. Salmonella sp. was only detected in the dairy. Isolates of L. monocytogenes and Salmonella sp. showed poor adhesion to polystyrene surfaces, virulence genes, and biofilm formation. The frequent contaminants in the slaughterhouses were Pseudomonas, Acinetobacter, and Aeromonas in poultry, Acinetobacter, Pseudomonas, and Brevundimonas in pork, and Pseudomonas, Kocuria, and Staphylococcus in dairy. Our results provide useful information to understand the microbiological risks associated with contamination.

Overview of antimicrobial resistance and virulence factors in Salmonella spp. isolated in the last two decades from chicken in Brazil.

Foodborne infections caused by Salmonella have been linked to a variety of poultry products. The aim of this study was to compare the molecular profile of virulence genes considering different serotypes of Salmonella, isolates were from chicken breast sampled during the last two decades (1999 to 2010 and 2011 to 2018). The resistance to antimicrobials was also evaluated, establishing a comparative epidemiological parameter on the pathogenic potential on this bacterium over time. We tested 238 Salmonella isolates, and 18 different serotypes were observed. These being S. Enteritidis (42.3%, 58/137) and S. Ohio (28.3%, 36/137), the most frequent in the first decade; and S. Heidelberg (25.7%, 26/101) and S. Typhimurium (21.8%, 22/101), in the second. We found four (1.68%) multidrug resistant isolates from the first decade and 28 (11.76%) in the second. All extended spectrum beta-lactamase (ESBL) positive isolates belonged to the S. Heidelberg serotype, and were also detected in the second decade. Considering the nine different antimicrobial classes tested, an increase in the number of resistant isolates was observed over time: from five classes with resistant isolates in the first decade to eight classes in the second, with cefotaxime being the antimicrobial with the highest number of resistant isolates in both decades. All isolates (100%) presented the invA, sitC and tolC genes. In sequence, the most frequent genes were flgL (99.6%), sopB (98.3%), flgK (97.9%), fljB (96.6%), sipA (94.9%), sipB (88.6%), sifA (86.4%), sipD (66.1%), ssaR (51.3%), sopD (37.3%) and spvB (34.3%) was the least frequent; and 13 isolates showing all 14 virulence genes investigated. The ability of these isolates to resist certain antimicrobials, and to express genes encoding virulence factors, reinforce their marked pathogenic potential; while the possibility to trigger diseases in humans through the food chain is a serious public health threat through.