RESUMO
Diarrheagenic E. coli (DEC) can cause severe diarrhea and is a public health concern worldwide. Cattle are an important reservoir for this group of pathogens, and once introduced into the abattoir environment, these microorganisms can contaminate consumer products. This study aimed to characterize the distribution of DEC [Shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), and enteroaggregative E. coli (EAEC)] from extensive and intensive cattle production systems in Brazil. Samples (n = 919) were collected from animal feces (n = 200), carcasses (n = 600), meat cuts (n = 90), employee feces (n = 9), and slaughterhouse water (n = 20). Virulence genes were detected by PCR in 10% of animal samples (94/919), with STEC (n = 81) as the higher prevalence, followed by EIEC (n = 8), and lastly EPEC (n = 5). Animals raised in an extensive system had a higher prevalence of STEC (average 48%, sd = 2.04) when compared to animals raised in an intensive system (23%, sd = 1.95) (Chi-square test, P < 0.001). From these animals, most STEC isolates only harbored stx2 (58%), and 7% were STEC LEE-positive isolates that were further identified as O157:H7. This study provides further evidence that cattle are potential sources of DEC, especially STEC, and that potentially pathogenic E. coli isolates are widely distributed in feces and carcasses during the slaughter process.
Assuntos
Escherichia coli Enteropatogênica , Infecções por Escherichia coli , Proteínas de Escherichia coli , Escherichia coli Shiga Toxigênica , Bovinos , Animais , Proteínas de Escherichia coli/genética , Brasil/epidemiologia , Sorotipagem , Escherichia coli Enteropatogênica/genética , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/veterinária , FezesRESUMO
This research was carried out to investigate the differences in adhesion and growth during biofilm formation of L. monocytogenes from different sources and clonal complexes. Biofilm by L. monocytogenes (isolates CLIST 441 and 7: both lineage I, serotype 1/2b, CC3; isolates 19 and 508: both lineage II, serotype 1/2c, CC9) was grown on stainless steel coupons under different stressing conditions (NaCl, curing salts and quaternary ammonium compounds-QAC), to determine the expression of different genes involved in biofilm formation and stress response. CLIST 441, which carries a premature stop codon (PMSC) in agrC, formed high-density biofilms in the presence of QAC (7.5% w/v) or curing salts (10% w/v). Reverse Transcriptase-qPCR results revealed that L. monocytogenes isolates presented differences in transcriptional profile of genes related to biofilm formation and adaptation to environmental conditions. Our results demonstrated how L. monocytogenes can survive, multiply and form biofilm under adverse conditions related to food processing environments. Differences in transcriptional expression were observed, highlighting the role of regulatory gene networks for particular serotypes under different stress responses.
Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Meios de Cultura/farmacologia , Listeria monocytogenes/fisiologia , Aço Inoxidável/química , Aderência Bacteriana , Técnicas Bacteriológicas , Biofilmes/efeitos dos fármacos , Meios de Cultura/química , Microbiologia de Alimentos , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/genética , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Cloreto de Sódio/química , Cloreto de Sódio/farmacologia , Estresse FisiológicoRESUMO
ABSTRACT: The ecology of Listeria monocytogenes and Pseudomonas spp. during the slaughtering of spotted sorubim (Pseudoplatystoma corruscans) in a fish processing facility was assessed. Fish samples (n = 28) were obtained in different points of slaughtering (A, arrival; B, washing; C, gutting; and D, cooling) and subjected to detection of L. monocytogenes and enumeration of Pseudomonas spp. High frequencies of Listeria spp. (17 of 28 to 22 of 28) and L. monocytogenes (6 of 28 to 9 of 28) were identified in all slaughtering points but were not significantly different (P ≥ 0.05). All L. monocytogenes isolates (n = 33) were identified as belonging to serogroup IVb (serotype 4b) and subjected to macrorestriction with ApaI and AscI. The results indicated a continuous entry of L. monocytogenes in the facility, as well as a temporary persistence of a specific pulsotype. Pseudomonas spp. counts significantly decreased between points A and D (P < 0.05), but the mean counts in the end products (D) remained higher than 3 log CFU/g, suggesting the potential for fast spoilage. The obtained results show that L. monocytogenes and Pseudomonas spp. are widely distributed during spotted sorubim slaughtering, indicating the need for proper hygienic procedures to control these bacteria in the processing facility.