Avaliação microbiológica do leite de caprinos criados no Semiárido Sergipano e susceptibilidade a agentes antimicrobianos in vitro

Abstract

The objective of this study was to determine the frequency and antimicrobial susceptibility profile of bacteria isolated from goat milk samples from some municipalities in the Brazilian state of Sergipe. The study included 28 goat farms in four municipalities of the Semiarid region of the State of Sergipe in Northeastern Brazil. All lactating does of each herd (n = 263) aged >1 year were, sampled randomly by non-probabilistic convenience sampling. Milk samples were collected from both teats, resulting in 526 samples in total. Bacterial culturing and isolation were performed, followed by antimicrobial susceptibility profile analysis to the following active principles: amoxicillin with and without clavulanic acid, amikacin, ampicillin with sulbactam, ciprofloxacin, cefalexin, cefalotin, ceftriaxone, chloramphenicol, doxycycline, enrofloxacin, gentamicin, levofloxacin, ofloxacin, penicillin G, and tetracycline. A survey form was used to obtain zootechnical information for each farm. Data are described as absolute and relative frequencies. The significance assessment of the differences between herd characteristics and bacterial isolation was performed using Pearson's chi-squared test. Bacterial isolation occurred in 15.4% (81/526) of the samples from 23.2% (61/263) of the goats. Escherichia coli (45,9%), Staphylococcus caprae (16,4%) and Enterococcus faecalis (11,5%), were the most frequently isolated species. Bacterial isolations were predominant in dairy herds with up to fifty animals, production of twenty to fifty liters/day and in the municipality of Porto da Folha. In terms of antimicrobial susceptibility, most isolates demonstrated resistance to penicillin and amoxicillin (88.5%), followed by ceftriaxone (23%), ofloxacin (23%), tetracycline (23%), doxycycline (19.7%), chloramphenicol (11.5%), levofloxacin (11.5%), ampicillin/sulbactam (8.2%), amikacin (6.6%), cephalothin (4.9%), cephalexin (3.3%) and gentamicin (3.3%). Approximately 20% of the isolates were multidrug resistant, especially E. coli (50%) and S. aureus (16.7%). E. coli was the most frequently isolated species from the samples. E. coli also stood out as the species presenting the most multidrug-resistant (MDR) isolates (50%), with strains resistant to beta-lactams, aminoglycosides, quinolones, tetracycline, and chloramphenicol. Coagulase-negative staphylococci are recognized as a public health problem as they are etiological agents of various diseases and can easily acquire antimicrobial resistance genes. Although it was not the most frequently isolated species, S. aureus was the species with the second-highest frequency of MDR strains.