en تخصصي Special Original article Original article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><strong>Background: </strong>Milk is a reservoir for several groups of microorganisms, which may pose health risks. The aim of this work was to assess the antibiotic resistance and biofilm production in catalase-positive Gram-positive cocci isolated from Brazilian pasteurized milk.<br> <strong>Methods:</strong> The bacteria were isolated using Baird-Parker agar and identified by Matrix-Assisted Laser Desorption/Ionization-Time-Of-Flight (MALDI-TOF) mass spectrometer. Disk diffusion technique was used to evaluate antimicrobial susceptibility. For qualitative evaluation of biofilm production, the growth technique was used on Congo Red Agar.<br> <strong>Results:</strong> Totally, 33 out of 64 isolates were identified, including <em>Staphylococcus epidermidis</em> (n=3; 4.7%), <em>Macrococcus caseolyticus</em> (n=14; 21.9%), and <em>Kocuria varians</em> (n=16; 25%). Twenty-two isolates were resistant to at least one antibiotic. Biofilm production was detected in only 5 isolates of <em>K. varians</em> and 1 isolate of <em>S. epidermidis</em>. All 14 <em>M. caseolyticus</em> isolates were resistant to at least one antibiotic; but, multidrug resistant (MDR) isolates were not detected. Among all <em>K. varians</em> isolates, 4 were resistant to at least one antibiotic from three different classes and were considered to be MDR.<br> <strong>Conclusion:</strong> The presence of antibiotic-resistant <em>M. caseolyticus</em>, <em>S. epidermidis,</em> and<em> K. varians </em>isolates, especially MDRs, in milk samples highlights the possible role of milk as a reservoir of resistance genes.<br> <br> <strong>DOI:</strong> 10.18502/jfqhc.7.2.2886</span></span></div> Gram-Positive Cocci, Drug Resistance, Microbial, Biofilms, Milk , Brazil 67 74 http://jfqhc.ssu.ac.ir/browse.php?a_code=A-10-901-1&slc_lang=en&sid=1 M.A.A. Machado 0000-0002-7361-4578 No Laboratório de Microbiologia, Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ), Rio de Janeiro, RJ, Brazil W.A. Ribeiro No Laboratório de Microbiologia, Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ), Rio de Janeiro, RJ, Brazil V.S. Toledo No Laboratório de Microbiologia, Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ), Rio de Janeiro, RJ, Brazil G.L.P.A. Ramos No Laboratório de Higiene e Microbiologia de Alimentos, Faculdade de Farmácia, Universidade Federal Fluminense (UFF), Niterói, RJ, Brazil H.C. Vigoder No Laboratório de Microbiologia, Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ), Rio de Janeiro, RJ, Brazil J.S. Nascimento janaina.nascimento@ifrj.edu.br 0000-0001-8822-8381 Yes Laboratório de Microbiologia, Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro (IFRJ), Rio de Janeiro, RJ, Brazil