Dados do Trabalho

Título

BENEFITS OF THE DEPURATION PROCESS IN OYSTERS FOR ELIMINATING ANTIMICROBIAL-RESISTANT BACTERIA

Introdução

Oysters, as filter-feeding animals of organic matter, have the potential to concentrate impurities present in the water column in their bodies, such as antimicrobial-resistant bacteria. The oyster depuration process significantly eliminates a large portion of the impurities acquired during the production process in the sea, but is still adopted by few restaurants. In this way, this study aimed to evaluate the impacts of depuration on reducing the presence of antimicrobial-resistant bacteria in oysters.

Material e Métodos

During summer and winter, samples of one liter of seawater and 15 oysters were collected directly from two oyster farmers. Additionally, one liter of depuration tank water and 15 depurated oysters were obtained from two restaurants supplied by the same producers. Water samples were filtered through 0.45 μm membranes, and oyster were homogenized. Both membranes and oyster samples were incubated in an enrichment medium for bacterial recovery. Aliquots from each enrichment medium were then added to selective pressure media with different classes of antibiotics (polymyxin, cefotaxime, ciprofloxacin, gentamicin, and ertapenem). Subsequently, samples were seeded on MacConkey agar, and each morphologically distinct colony was isolated and identified by MALDI-TOF. An antimicrobial susceptibility test was then performed using the disk diffusion method.

Resultados e Discussão

During the summer, 25 antimicrobial-resistant bacterial isolates were collected, 11 from seawater samples and 14 from oyster samples. Among these, 40% were classified as multidrug-resistant, and 48% exhibited the Extended-Spectrum Beta-Lactamase (ESBL) phenotype. After the depuration process, only 7 resistant isolates were obtained, 3 from the depuration tank water and 4 from oyster samples. Of these, only 28.57% exhibited multidrug resistance, and none exhibited the ESBL phenotype. In winter, 9 isolates were collected, 5 from seawater and 4 from oyster samples. Among these, 44.44% were multidrug-resistant, and 55.55% exhibited the ESBL phenotype. Following depuration, the number of resistant isolates reduced to 5, with none showing multidrug resistance and only one (25%) exhibiting the ESBL phenotype.

Conclusão

The results demonstrate that the depuration process of oysters reduces the number of resistant isolates present in these products and decreases the level of contamination related to the presence of multidrug-resistant microorganisms and those with the ESBL phenotype.