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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.

Pretendeu-se identificar anticorpos contra a sorovariedade icterohaemorrhagiae, sendo esta a mais prevalente em equinos, e contra as sorovariedades icterohaemorrhagiae, pomona, wolffi, hardjo e canicola e relacionar possiveis alteracoes na bioquimica serica com a infeccao por Leptospira interrogans. Foram colhidas amostras de sangue de 17 equinos higidos e 8 enfermos, pertencentes a Universidade Federal de Uberlândia. Nenhum destes animais era suspeito clinicamente para leptospirose. Foi realizado o teste de soroaglutinacao microscopica e posterior titulacao das amostras positivas. Tambem foram realizadas analises de bioquimica serica quanto as concentracoes de ureia, colesterol, creatinina, proteinas totais e albumina, alem da atividade das enzimas hepaticas aspartato aminotransferase, gama glutamiltransferase e fosfatase alcalina. Os resultados evidenciaram que 20% dos animais estudados foram sororreagentes para Leptospira interrogans. Os equinos foram sororreagentes para as sorovariedades hardjo, autumnalis, pomona, pyrogenes, canicola e tarassovi. Quanto as analises bioquimicas sericas, foram observadas alteracoes quando as concentracoes foram comparadas aos intervalos sugeridos como normais pela literatura. A sorovariedade icterohaemorrhagiae nao foi a mais comum nos equinos estudados, porem, as sorovariedades hardjo, pomona e canicola foram as mais frequentes e as alteracoes na bioquimica serica dos animais nao puderam ser relacionadas a infeccao por Leptospira interrogans.

O objetivo deste trabalho foi analisar a frequência de lesões macroscópicas sugestivas de tuberculose em carcaças de bovinos reagentes ao teste intradérmico de tuberculose. Os animais do estudo foram provenientes de rebanhos de exploração leiteira, localizados nos municípios de Perdizes, Patos de Minas, Lagoa Formosa e Uberlândia, Minas Gerais. Foram avaliadas 140 carcaças de bovinos positivos no teste cervical comparativo. Durante o abate sanitário foi realizada inspeção post mortem das carcaças, e as lesões macroscópicas sugestivas de tuberculose foram registradas. Foram avaliados os linfonodos mediastínicos, fígado, pulmão e carcaça. Dos 140 bovinos examinados, 78 (55%) apresentaram algum tipo de lesão macroscópica sugestiva de tuberculose, 38 (49%) ocorreram exclusivamente nos linfonodos mediastínicos, 22 (28%) no fígado e 11 (14%) no pulmão; 5 (6%) carcaças apresentaram lesões no fígado, pulmão e linfonodo mediastínico, e 2 (4%) tiveram lesões no pulmão e linfonodo. Concluem-se que as lesões não visualizadas em bovinos reagentes ao teste tuberculínico podem ocorrer e estariam relacionadas principalmente ao estágio de evolução da doença, tempo insuficiente na inspeção post mortempara detecção, bem como reações inespecíficas para outras micobactérias. The aim of this study was to analyze the frequency of macroscopic lesions suggestive of tuberculosis in cattle reacting to the tuberculin test. Cattle of this study were from dairy herds located in the cities of Perdizes, Patos de Minas, Lagoa Formosa and Uberlândia, Minas Gerais, Brazil. We evaluated 140 cattle carcasses positive to the cervical comparative intradermal tuberculin test. During the slaughter a post-mortem inspection of carcasses was done, and the lesions suggestive of tuberculosis were recorded. We evaluated the mediastinal lymph nodes, liver, lung and carcass. Of the 140 cattle examined, 78 (55%) carcasses had some kind of macroscopic lesions suggestive of tuberculosis, 38 (49%) occurred only in the mediastinal lymph nodes, 22 (28%) in the liver and 11 (14%) in the lungs; 5 (6%) carcasses showed lesions in liver, lungs and lymph node, and 2 (4%) showed lesions in lung and lymph nodes. We concluded that lesions that were not visualized in bovine tuberculin skin test reagents may occur and are related mainly to the stage of the disease, insufficient time to detect the lesions, and nonspecific reactions to other mycobacteria.

The original version of this article unfortunately contains an error. Vanessa do Nascimento Ramos was not included in the original article as one of the contributors. The name is now included in the authorgroup.

Leptospirosis is a zoonotic disease of world importance, and its transmission depends on the interaction between humans and animals. Given the necessity to investigate potential hosts of Leptospira spp., this study verified the prevalence of different serovars in the species of Rhipidomys spp., a widespread sigmodont rodent in Brazil. The studied population originates from a semi-evergreen forest located in the county of Uberlândia, in the state of Minas Gerais. The microscopic agglutination test (MAT) was performed with 14 serovars. Thirteen out of the 43 wild rodents captured showed a positive agglutination reaction, with a greater prevalence of the serovars Pyrogenes, Copenhageni, and Canicola. This study found a prevalence of 30.3% anti-Leptospira spp. antibodies; all positive animals were reactive to more than one serovar.

RESUMO: Leucose e tuberculose são doenças que acometem o rebanho bovino e acarretam consideráveis prejuízos econômicos, em virtude do impacto na produtividade, porém há poucos relatos de que elas ocorram concomitantemente. Diante disso, objetivou-se avaliar a intercorrência entre essas doenças em bovinos abatidos no município de São Gotardo, MG, sendo que esses animais foram reagentes à tuberculinização e apresentaram lesões características da doença durante o abate sanitário. Cento e trinta e três amostras de soro sanguíneo, todas oriundas de bovinos positivos para tuberculose, foram analisadas pela técnica de imunodifusão em gel de ágar (IDGA), e a prevalência de bovinos que apresentaram positividade ao teste de IDGA foi de 55,64% (74/133). Os resultados obtidos nesta pesquisa permitiram concluir que a tuberculose e a leucose são doenças presentes nas regiões estudadas e encontram-se disseminadas na população avaliada, com níveis significativos, causando risco à saúde dos animais e das pessoas, dado o caráter zoonótico da tuberculose bovina. ABSTRACT: Leukosis and tuberculosis are diseases that affect cattle and entail considerable economic losses, due to theim pact on productivity, but there are few reports that they occur simultaneously. Therefore, aimed to evaluate the complications of these diseases in cattles laughtered in São Gotardo, MG, these animals were positive to the tuberculin and showed lesions characteristic of the disease during the stamping. One hundred and thirty three samples of blood serum, all from positive to bovine tuberculosis, were analyzed by immuno diffusion technique in agar gel (AGID), and the prevalence of cattle that were positive by AGID test was 55.64% (74/133). The results of this research showed that tuberculos is and leukosis are diseases present in the studied regions and are disseminated in this population, with significant levels, causing risk to the health of animals and people, as the zoonotic bovine tuberculosis.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior A dissertação foi dividida em dois estudos. Com o primeiro, objetivou-se avaliar a ocorrência de microrganismos presentes na região vulvovaginal de vacas que receberam dispositivos intravaginais de progesterona durante os programas de inseminação artificial em tempo fixo (IATF), e correlacionar os resultados com as taxas de prenhez. As amostras foram coletadas da região vulvovaginal de 30 vacas de corte Guzerá e 30 vacas leiteiras mestiças, e também dos dispositivos intravaginais, aleatoriamente. Das 120 amostras coletadas das vacas, 60 corresponderam ao período anterior à introdução do dispositivo (D0) e 60 ao posterior à retirada do mesmo (D9); obteve-se 100% de crescimento bacteriano, sendo que, na maioria das amostras, encontrou-se mais de um isolado. No D0, o agente de maior frequência foi a Escherichia coli (52%), e no D9, Proteus spp e E.coli foram os mais encontrados (32% e 28%, respectivamente). Em relação aos dispositivos intravaginais de progesterona, no D0 foram isolados 37 microrganismos, sendo predominantes os do gênero Bacillus (35%); já no D9 foram isoladas 41 unidades formadoras de colônias (UFC), sendo que 36,6% corresponderam ao Proteus spp. Para a análise do perfil antimicrobiano, realizou-se antibiograma por difusão do disco em ágar, e foram selecionadas as vacas que não emprenharam após a IATF, a título de tratamento futuro. Houve resistência de 100% à penicilina, e sensibilidade de, aproximadamente, 90% à gentamicina, tanto para os isolados obtidos das amostras das vacas de corte quanto para os obtidos das vacas de leite. Em relação à taxa de prenhez, das 30 vacas de corte, 11 foram diagnosticadas prenhes (36,7%), sendo 4 (36,4%) tratadas com dispositivos intravaginais reutilizados e 7 (63,6%) com dispositivos novos, que se mostraram mais eficazes. Das 30 vacas de leite, 15 (50%) emprenharam, sendo que 8 (53,3%) foram implantadas com dispositivos reutilizados e 7 (46,7%) com dispositivos novos, não havendo diferenças significativas entre as taxas de prenhez. Por se tratar de uma pesquisa, as fêmeas foram escolhidas ao acaso, e fatores como escore corporal, manejo nutricional e sanitário não foram prioridade. Com o segundo estudo, objetivou-se analisar a similaridade entre cepas, realizada pela técnica Random Amplified Polymorphic DNA (RAPD-PCR). A presença de E.coli e a ausência de prenhez foram os critérios de seleção utilizados. Diante dos resultados, observou-se que a maioria dos isolados não foi filogeneticamente semelhante, uma vez que apresentaram similaridade inferior a 85%. O estudo ressaltou a importância da E. coli na microbiota vulvovaginal de vacas e a presença de caracteres fenotípicos e genotípicos dessa bactéria em possíveis problemas reprodutivos. The dissertation was divided in two studies. With the first, aimed to evaluate the occurrence of microorganisms present in the vulvovaginal region of cows that received intravaginal progesterone devices during the fixed-time artificial insemination (FTAI) programs, and correlate the results with pregnancy rates. Samples were collected from vulvovaginal region of 30 beef cows Guzerá and 30 crossbred dairy cows, and also intravaginal devices, randomly. Of the 120 samples of cows, 60 corresponded to the collections of the period prior to the introduction device (D0) and 60 to the subsequent withdrawal of it (D9); it yielded 100% of bacterial growth, whereas, in most samples, it was found more than one isolated. In D0, the most frequent agent was Escherichia coli (52%), and in D9, Proteus spp and E. coli were the most frequent (32% and 28%, respectively). Regarding intravaginal progesterone devices, in D0 were isolated 37 microorganisms, being predominant those of the genus Bacillus (35%); in D9, 41 colony forming units (CFU) were isolated, of which 36.6% corresponded to Proteus spp. For the analysis of the antimicrobial profile, susceptibility testing was performed by diffusion agar disk, and cows that did not became pregnant after FTAI program were selected, as a future treatment. There resistance 100% to penicillin, and sensitivity, approximately, 90% to gentamicin, both isolates obtained from samples of beef cows and obtained of dairy cows. Regarding pregnancy rate, the 30 beef cows, 11 were diagnosed pregnant (36.7%), 4 (36.4%) treated with reused devices and 7 (63.6%) with new devices, which showed more effective. Of the 30 dairy cows, 15 were pregnant (50%), 8 (53.3%) were implanted with reused devices and 7 (46.7%) with new devices, with no significant differences in pregnancy rates. Because it is a research, females were chosen at random, and factors such as body condition, nutritional management and health weren't priority. With the second study, aimed to analyze the similarity between strains, conducted by technical Random Amplified Polymorphic DNA (RAPD -PCR). Presence of E. coli and the absence of pregnancy were selection criteria used. From the results, it was observed that most of the isolates wasn't phylogenetically similar, since they showed lower than 85% similarity. The study stressed the importance of E. coli in vulvovaginal microbiota of cows and the presence of phenotypic and genotypic characters of this bacterium on possible reproductive problems. Dissertação (Mestrado)

RESUMO: Objetivou-se com este estudo comparar diferentes métodos complementares de diagnóstico (macroscópico, histopatológico, sorológico e molecular) da tuberculose, em bovinos naturalmente infectados. O trabalho deu-se por meio de amostras colhidas em abate sanitário de 40 bovinos reagentes no teste cervical comparativo (TCC) para tuberculose. A inspeção macroscópica post mortem das carcaças foi acompanhada de colheita de amostras de muco nasal, sangue e tecido (fígado, pulmão e linfonodo mediastínico) para realização do exame de reação em cadeia pela polimerase (PCR), de Enzyme-Linked Immunosorbent Assay (ELISA) e histopatológico com colorações de hematoxilina-eosina (HE) e Ziehl-Neelsen (ZN), respectivamente. Dos 40 bovinos inspecionados no abate, 22 (55%) animais apresentaram algum tipo de lesão macroscópica sugestiva de tuberculose. Nos achados histopatológicos visualizados em HE, 13 (32,5%) carcaças apontaram alterações histológicas, sendo 6 (15%) nos linfonodos mediastínicos, 5 (12,5%) no fígado e 3 (7,5%) no pulmão. Não foi observada a presença de bacilos álcool-ácido resistentes em nenhuma das amostras avaliadas. O ensaio sorológico de ELISA/IDEXX(r) identificou um (2,5%) animal reagente, e o teste de PCR detectou DNA de Mycobacterium bovis em uma (2,5%) amostra. Concluiu-se que entre os exames complementares de diagnóstico avaliados nenhum foi capaz de detectar todos os animais que estavam positivos na tuberculinização, porém a associação de diferentes métodos pode garantir a confiabilidade do diagnóstico. ABSTRACT: The aim of this study was to compare different complementary diagnostic methods (macroscopic, histological, serological and molecular) of tuberculosis in naturally infected cattle. The study was conducted from samples taken from 40 reagents cattle in cervical comparative intradermal tuberculin test (ITT). The macroscopic post mortem inspection of carcasses was followed by the collection of nasal swabs, blood and tissue samples (liver, lung and mediastinal lymph node) for polymerase chain reaction (PCR) test, Enzyme-Linked Immunosorbent Assay (ELISA) and histopathologic test with hematoxylin-eosin (HE) and Ziehl-Neelsen (ZN), respectively. Of the 40 cattle slaughtered, 22 (55%) carcasses had macroscopic lesions suggestive of tuberculosis. The histopathology HE identified 13 (32.5%) carcasses with histological changes: 6 (15%) in the mediastinal lymph nodes, 5 (12.5%) in the liver and 3 (7.5%) in the lung. At ZN, the presence of acid-fast bacilli was not detected in any of the samples tested. The ELISA/IDEXX(r) identified one (2.5%) reagent animal, and the PCR test detected DNA of Mycobacterium bovis in one (2.5%) cow. It is concluded that among the diagnostic methods reviews none was able to detect all animals that were positive in tuberculin test, but the association of different methods can ensure diagnostic accuracy.

Background: Leptospirosis is a zoonosis that affects many species of mammals and occurs endemically in Brazil. The biofilm matrix provides structure and protection to the biofilm cells working as a physical barrier to antibiotic agents, which are attached or consumed by the matrix components. However, this attribute varies according to the matrix, antimicrobial agent and biofilm age. Leptospira may change morphologically according to environmental conditions, including cell aggregation and biofilm formation. Leptospira can colonize the ducts of kidney from hosts for a long time, forming a biofilm, which is believed to be an important factor for their maintenance in animals and in the environment. Thus, the objective of this research was to determine the biofilm formation capacity of four strains of Leptospira interrogans.Materials, Methods & Results: The strains were typified by WHO/FAO/OIE and National Collaborating Center for Reference and Research on Leptospirosis (Kit Biomedical Research, Amsterdam, Netherlands). Leptospira interrogans strains, two isolated from cattle and two isolated from dogs were biofilms tested for adhesion on polystyrene plates, extracellular matrix composition and confocal microscopy. In the plating adhesion test, the suspension was inoculated into 96-well sterile polystyrene microplates with flat bottom at a ratio of 1:200 in EMJH medium, followed by 24 h incubation at 28°C, with medium renewal after 12 h. After this period the wells were washed three times with sterile PBS and following incubation; the plates were dried in the oven at 60°C for 30 min and added 200 μL of 1% violet crystal for five min. Subsequently, the plates were washed with distilled water, after complete removal, 200 μL of acetic acid 33% was added and the readings were performed at 570 nm in the ELISA reader. The proteins and polysaccharides were quantified in a scraped pooled sample diluted in 0.85% sterile saline solution to achieve an optimal amount for testing used reagents of the BCA kit. The polysaccharide content was determined by adding into a tube, an aliquot of 0.5 mL from the pooled sample, 0.5 mL of phenol and then immediately 2.5 mL of sulfuric acid. The solution was homogenized and left to react for 15 min at room temperature. The reading was performed at 490 nm in ELISA reader. The strains were compared regarding polysaccharides and protein matrices using analysis of variance (ANOVA) and Tukey test. At confocal microscopy the strains were incubated with the tested polypropylene material for 24 h. The materials were washed with sterile phosphate buffer and stained with propidium iodide. The reading was performed using a Laser Scanning Confocal Microscope (Zeiss 710) with laser excitation (488 nm) and 580-680 nm emission filters for propidium iodide (red marking). All strains displayed strong adherence on microplate and the amount of polysaccharides in biofilm was not statistically different among the studied strains, but the amount of protein was significantly different in strain 4 (P > 0.5). The confocal microscopy showed the adherence of the Leptospira spp. strains to polypropylene material after washing.Discussion: Biofilm production plays an important role in the maintenance of a chronic infection by Leptospira interrogans with renal colonization. The exopolysaccharide (EPS) has various functions, such as checking insolubility in water; giving the three-dimensional conformation of the biofilm; protecting cells from physical (mechanical action, irradiation and temperature variations), chemical.

Leptospirosis is a zoonosis of worldwide distribution with high incidence in tropical regions.Leptospirosis in dogs presents with large clinical polymorphism and these animals are consideredsources of infection for human leptospirosis, even without showing any clinical signs. Pathogenesisis characterized by the development of vasculitis, endothelial injury and infiltration of monocyticcells, plasma cells, histiocytes and neutrophils. The objective of this study was to report the caseof a dog serologically positive for leptospirosis. The animal died and then was submitted to theAnimal Pathology Department of the Veterinary Hospital of the Federal University of Uberlândia. At necropsy hemolytic jaundice and moderate chronic interstitial nephritis were diagnosed. Themacroscopic, histological and serological changes suggest severe hemolytic disease consistent withleptospirosis.

The white-eyed parakeet ( Aratinga leucophthalma ), also known in Brazil as “periquitao-maracana,” “aratinga-de-bando,” “araguai” and “maritaca,” belongs to the family Psittacidae . The fungal genus Malassezia , which lives on the surface of the skin and mucosae of some mammals and birds, is a commensal organism that may sometimes act as a pathogen. This paper describes the presence of Malassezia spp at the edge of the eye of a white-eyed parakeet seized by IBAMA (Brazilian Institute of Environment and Renewable Natural Resources­) and examined at the Federal University of Uberlândia (UFU) Veterinary Hospital. The examination of the bird revealed the presence of a small white rounded structure at the edge of its right eye. The bird was sedated and a fragment of the structure was removed and sent to the university’s Laboratory of Infectious Diseases. This material was seeded in blood and MacConkey agars and a slide was prepared and stained by the Gram-staining technique; no biochemical assays were performed. Reading was performed in an optical microscope under 100X magnification, revealing flattened oval colonies resembling purplish footprints, indicative of Malassezia spp. The bird was not treated because the structure gradually diminished in size until it disappeared completely after the animal was isolated in a clean well ventilated place and supplied with water and good quality food suitable for the species. It is believed that the development of the atypical and uncommon foreign body in the bird’s eye may have been caused by immunodepression resulting from the period of stress it underwent during wildlife trafficking.

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.