Contamination and antimicrobial resistance profile of Escherichia coli in chicken carcasses from public markets in Maranhão / Contaminação e perfil de resistência antimicrobiana de Escherichia coliem carcaças de frango de mercados públicos maranhenses

Contamination of chicken meat sold in public markets is a public health concern. The objective of this study was to identify contamination and evaluate the antimicrobial resistance profile of Escherichia coli in chicken carcasses from public markets in the North Mesoregion of Maranhão. A total of 160 freshly slaughtered chicken carcasses were collected in 16 markets in six municipalities in the microregions of Itapecuru-Mirim and São Luís. The samples were analyzed for the presence of E. coli using counting thermotolerant coliforms and classified according to the ANVISA microbiological standard. Of all the samples, 134 (83.75%) were considered unacceptable for consumption, according to Brazilian health legislation. Bacteria were isolated from the positive samples, and 50 isolates were tested for susceptibility to 15 antimicrobial principles using the disc diffusion method. The results confirm the presence of E. coli, with counts ranging from 101 to 108 NMP/g. The isolates showed resistance to neomycin (49/50, 98%), streptomycin (48/50, 96%), sulfonamides (47/50, 94%), nitrofurantoin (45/50, 90%), cefazolin (43/50, 86%), and tetracycline (43/50, 86%). No antibiotic was effective against the isolates, which were resistant to more than 3 antimicrobial classes considered resistant to multiple drugs (MDR). Therefore, chicken meat sold in public markets in Maranhão presents unsatisfactory conditions for consumption and risk of transmission of E. coli with an MDR profile.(AU)

A contaminação da carne de frango comercializada em mercados públicos é uma preocupação de saúde pública. Nesse sentido, objetivou-se avaliar a contaminação e perfil de resistência antimicrobianas de Escherichia colidas carcaças de frango de mercados públicos da Mesorregião Norte do Maranhão. Foram coletadas 160 amostras de carcaças de frango recém--abatidas e comercializadas em 16 mercados de seis municípios das microrregiões de Itapecuru-mirim e São Luís. As amostras foram analisadas quanto à presença de E.coli por meio da contagem de coliformes termotolerantes e classificadas segundo o padrão microbiológico da ANVISA. A bactéria foi isolada de amostras positivas. Testou-se 50 isolados quanto à suscetibili-dade a 15 princípios antimicrobianos, seguindo o método de Difusão em Disco.Os resultados confirmam a presença de E.coli com contagens de 101 a 108 NMP/g. De todas as amostras 134 (83,75%) foram consideradas inaceitáveis para consumo, con-forme legislação brasileira sanitária. Os isolados mostraram alto índice de resistência atimicrobiana aos princípios neomicina (49/98%), streptomicina (48/96%), sulfanomidas (47/94%), nitrofurantoína (45/90%), cefazolina (43/86%) e tetraciclina (43/86%). Nenhum antibiótico foi eficaz contra os isolados, sendo resistente a mais de 3 classes antimicrobianas considerados resistente a múltipla a drogas (MDR). A carne de frango comercializada nos mercados públicos maranhenses apresenta con-dições insatisfatórias para consumo e risco de transmissão de E. coli com perfil MDR.(AU)

Lactic acid bacteria against Listeria monocytogenes

Listeria monocytogenes is a pathogenic bacterium that can contaminate food and cause public health problems due its ability to form biofilms and resistance to sanitizers, it is responsible for sanitary and economic losses in food producing establishments. The difficulties in controlling biofilms and increasing resistance to traditional antibacterial agents is motivating studies of alternative potential biological agents for the control of pathogenic biofilms, among which lactic acid bacteria (LABs) are included. The objective of this work was to evaluate the activity of LABs against Listeria monocytogenes biofilm formation on polystyrene plates, a surface commonly used in the food industry. Lyophilized commercial strains of Bifidobacterium animalis, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus salivaris and Lactobacillus acidophilus were used. The strain of Listeria monocytogenes (L4) was isolated from polystyrene mats from a poultry slaughterhouse cutting room and demonstrated the ability to attach to microplates and resistance to sanitizers (sodium hypochlorite and hydrogen peroxide) at all times, temperatures and tested surfaces. The antimicrobial activity of LABs was evaluated by the agar diffusion method. The LABs that presented action on Listeria monocytogenes were selected for the inhibition and/or removal of biofilms in microplates, and all experiments were carried out in triplicate. Only Bifidobacterium animalis and Lactobacillus plantarum demonstrated action against Listeria monocytogenes in the agar diffusion assays and were selected for inhibition and competition assays. Furthermore, competition of LABs against Listeria monocytogenes adhesion was evaluated. There was no significant difference between LABs and L. monocytogenes, alone or in combination, at temperatures of 30ºC and 37ºC in the Listeria monocytogenes inhibition assays on polystyrene surface. The lactic acid bacteria evaluated did not demonstrate inhibition of L. monocytogenes adhesin testes with optical density visualization, however, it was possible to identify a reduction in L. monocytogenes counts with the application of Bifidobacterium animals and Lactobacillus plantarum in the testes of competition against biofilm formation. In competition tests Bifidobacterium animalis and Lactobacillus plantarum have an injunction in Listeria monocytogenes, indicating that these lactic acid bacteria can retard Listeria biofilm formation on polystyrene surfaces and thus help control the pathogen in the food industry. A potential mechanism to control biofilm adhesion and formation of pathogens for nutrients and fixation on surfaces, multiplication factors and surfaces are a challenge in controlling biofilms of pathogenic microorganisms, alternative measures to traditional methods for inactivating pathogens and biofilm formers bacteria are necessary. In this sense, lactic acid bacteria generate high levels of bacteriocin and are effective in inhibiting the biofilm of pathogenic bacteria, however, our study did not reveal this. We verified that Bifidobacterium animalis and Lactobacillus plantarum have an inhibitory action on Listeria monocytogenes, indicating that these lactic acid bacteria can be used to delay the formation of biofilms by Listeria on polystyrene surfaces, helping to control this pathogen in food industry.(AU)