Produção de biofilme e susceptibilidade in vitro a desinfetantes de Staphylococcus coagulase positiva isolados de leite bovino / Biofilm production and in vitro susceptibility to disinfectants of Staphylococcus coagulase positive isolated from bovine milk

ABSTRACT

Background: Mastitis is one of the diseases that cause damage to dairy cattle, and coagulase positive Staphylococcus (CPS),are its main etiological agents. The production of biofilms gives these microorganisms a physiological advantage, being animportant virulence factor, as it confers their resistance to the action of disinfectants used in hygiene procedures. Therefore,the objective of this study was to evaluate the capacity of CPS, isolated from milk samples from cases of bovine subclinicalmastitis in the Alagoas dairy basin, biofilm production and its sensitivity to disinfectant agents used before and after dipping.Materials, Methods & Results: In the Alagoas Milk Basin Region, 10 properties were selected from the municipalities ofBatalha, Cacimbinhas, Major Isidoro and Minador do Negrão, which used a mechanical milking system and supplied milk toa dairy under federal inspection. The California Mastitis Test (CMT) was performed on 1155 cows. The animals diagnosedwith subclinical mastitis were classified as mild (+); moderate (++) and severe (+++). CMT positive samples were collectedfrom 2+, totaling 891 samples. After cleaning the papillary ostium, 2 to 5 mL of milk was collected from each fourth breastbefore milking began. Subsequently, 0.5 µL of each sample was streak plated by exhaustion on 5% Sheep Blood Agar andincubated at 37°C, with readings at 24 and 48 h. The macroscopic and microscopic characteristics of the colonies, catalaseand coagulase test were evaluated. Biofilm formation was determined by the microplate adhesion test. The efficacy of thesanitizers was evaluated with the active ingredients lactic acid (2%), allantoin (0.05%), iodine (0.5%), chlorhexidine (2.0%),chlorine (2.5%), at times 15, 30 and 60 seconds. It was observed that 91.2% of the samples were able to form biofilm; Of these,22.2%, 29.6% and 48.2% were strong, moderate and weak producers, respectively. The sensitivity profile of chlorhexidine...