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The presence of biofilm-forming bacteria from the mammary gland of dairy cows adhered to equipment in the milking environment represents one of the major causes of bacterial resistance during mastitis treatment. The aim of this study was to identify strains of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli in milk samples from cows with mastitis, as well as in the expansion tank and milking set liners. We aimed to quantify the extracellular proteins and polysaccharides in the biofilm produced by each strain. A total of 294 samples were collected from a dairy farm in the municipality of Uberlândia, Minas Gerais. To identify the S. aureus, S. epidermidis and E. coli isolates responsible for biofilm production, we tested the phenotype using the Congo red agar (CRA) and microplate adhesion tests. Protein quantification was performed with a Bicinchoninic Acid Protein Assay Kit (BCA kit), and polysaccharides were quantified by the phenol sulfuric acid method. We identified eight strains of S. aureus, one strain of S. epidermidis and 11 strains of E. coli responsible for biofilm production, all of which showed a higher concentration of polysaccharides than proteins in the matrix. Escherichia coli was considered the most prevalent bacterium among the samples, and S. aureus was determined to be the largest biofilm producer. The results of the CRA and microplate adhesion tests were similar in regard to identification of the biofilm-producing strains according to their phenotype and matrix composition. The classification of S. aureus strains as major biofilm producers is of great concern for producers, as such bacteria are considered one of the predominant contagious etiological agents that cause bovine mastitis. In addition, our observation that E. coli and S. epidermidis can produce biofilms highlights the need to reassess prophylactic measures to avoid the adhesion of biofilm-producing bacteria.

This study evaluated the microbiological quality of the water of 33 poultry sheds seeking to identify the presence of biofilm-producing Escherichia coli. The swab samples of the surface of the drinkers were analyzed by the inhibition test to detect the most effective disinfectant for removing these bacterial communities. The multiple-tube and mesophilic counts techniques were used to analyze the water samples. The swabs were plated on EMB agar followed by Rugai medium to identify E. coli . The biofilm was detected by the optical density readings and the Congo red agar method. Overall, 15 strains of Escherichia coli were detected in the swabs of the drinkers, of which 8 were biofilm producers. Regarding the water quality, 15 (45.45%) of the 33 evaluated water samples had bacterial growth while only two (13.33%) produced gas. The test with disinfectants showed that chlorine and chlorhexidine were not effective to control the E. coli biofilm production. Therefore, a strict control is essential to ensure the safety of the water supplied to the animals in broiler sheds and to eliminate the biofilm-forming E. coli that have shown to be potentially resistant to the sanitizers commonly used in the cleaning processes.

Made available in DSpace on 2022-04-28T19:01:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-01 Staphylococcus is an important agent of mastitis, especially when biofilm producers are related to a number of mechanisms of resistance to different types of infections. The objective of this research was to evaluate the susceptibility and resistance of Staphylococcus aureus strains isolates from cases of bovine mastitis and milking environment under conditions of biofilm, compared to three different concentrations in different antimicrobials. Thirty-two strains used were S. aureus that, due to the inhibition tests, minimal biofilm eradication concentration were tested using cephalexin, amoxicillin and rifampin at concentrations of 30 mg/mL, and 50 mg/mL 100 mg/mL for 12 hours, and efficiency of tests evaluated by counting the colony forming units and the microplate test. The results revealed that among the tested antibiotics cephalexin showed the best efficiency at the three concentrations tested, and rifampin and amoxicillin were more efficient at concentrations of 50 and 100 mg/mL. These data demonstrate the importance of targeted antibiotic therapy associated with the correct cleaning of milking equipment, thus, preventing the formation of biofilm, avoiding persistent microbial adhesion in equipment, and the spread of microorganisms by ascending channel teats among herd animals. Universidade Federal de Uberlandia Universidade Estadual de Santa Cruz Universidade Federal de Uberlandia, Instituto de Ciencias Biomedicas, Area de Imunologia Microbiologia e Parasitologia Universidade Estadual Paulista “Julio de Mesquita Filho”, Departamento de Medicina Veterinaria Preventiva e Reproducao Animal Universidade Estadual Paulista “Julio de Mesquita Filho”, Departamento de Medicina Veterinaria Preventiva e Reproducao Animal

A prevalencia da mastite por Staphylococcus aureus em rebanhos leiteiros ocorre devido a sua alta infectividade associada a fatores de virulencia que conferem ao micro-organismo a capacidade de se instalar no parenquima mamario. Objetivou-se avaliar o perfil de sensibilidade e resistencia de estirpes de Staphylococcus aureus produtoras de biofilmes isoladas de casos de mastite bovina e ambiente de ordenha. Foram avaliadas 32 estirpes, sendo 28 isoladas de leite de vacas com mastite, duas isoladas de insufladores, uma isolada de mangueira condutora de leite e uma do leite do tanque de expansao. Apos o isolamento e caracterizacao das estirpes como Staphylococcus aureus foram realizados testes para avaliar a capacidade de producao de biofilmes pelo teste de microplacas, e o perfil de sensibilidade e resistencia de estirpes em modelo de adesao em biofilmes frente ao antimicrobiano cefalexina nas concentracoes de 30mg/mL e 100mg/mL no tempo de 12 horas de contato das bacterias com o antimicrobiano. Os resultados revelaram que apos a producao de biofilmes de 32 estirpes, 2 (6,25%) foram resistentes a cefalexina na concentracao de 30mg e 8 (25,00%) foram resistentes na concentracao de 100mg. A alta concentracao de cefalexina tornou ineficaz a penetracao do antimicrobiano pela matriz do biofilme dificultando sua atuacao, sabendo-se que as bacterias quando em biofilmes estao mais resistentes do que na forma livre. Por isso, e importante realizar uma correta avaliacao do uso e da concentracao dos antimicrobianos para o adequado tratamento das infeccoes, principalmente das mastites estafilococicas. SUMMARY The prevalence of mastitis transmitted by Staphylococcus aureus in dairy herds is due to its high infectivity rate associated with virulence factors that give the micro-organism the ability to settle in the breast. This study aimed to evaluate the sensitivity and resistance of Staphylococcus aureus strains capable of producing biofilms in isolates from cases of bovine mastitis and milking environment. We evaluated 32 strains, 28 strains isolated from milk of cows with mastitis, two isolated from vacuum tubes, one isolated from the milk hose and another from the milk of the expansion tank. After isolation and characterization of strains such as Staphylococcus aureus, tests were performed to evaluate biofilms production capacity using the microplate test, and the susceptibility profile and resistance of strains using the biofilm adhesion model against the antimicrobial cephalexin at concentrations of 30 and 100 mg/mL for 12 hours of contact time of the bacteria with the antimicrobial. The results showed that after production of biofilms of 32 strains, 2 (6.25%) were resistant to cephalexin concentration of 30 mg while 8 (25.00%) were resistant at the concentration of 100 mg. The high concentration of cephalexin rendered ineffective the antimicrobial penetration by the biofilm matrix hindering its performance; it is known that when the bacteria are in biofilms they become more resistant than in the free form. It is concluded that it is important to make a correct assessment of the use and concentration of antimicrobials for the appropriate treatment of infections, particularly of staphylococcal mastitis.