Antibiotic resistance in culturable bacteria isolated from Ucides occidentalis crab in the largest mangrove swamp in Peru

Antibiotic resistance is a global problem affecting diverse ecosystems, including mangroves. The mangrove crab Ucides occidentalis is the most exploited crustacean for human consumption in the mangroves of Peru and Ecuador. Therefore, the presence of antibiotic–resistant bacteria must be monitored to protect consumer health. The aim of this research was to determine antibiotic resistance in cultivable bacterial strains isolated from U. occidentalis in the Tumbes mangrove, the largest mangrove forest in Peru. Thirty crabs were collected, sacrificed, and samples of their hepatopancreas, intestine, and hemolymph were cultured on thiosulfate citrate bile sucrose agar and trypticase soy agar. The colonies were subcultured to obtain pure strains, which were molecularly identified, and their resistance to 12 antibiotics was evaluated. As a result, 35 bacterial strains were isolated from the genera: Vibrio (17), Bacillus (9), Staphylococcus (4), Enterobacter (2), as well as Exiguobacterium, Halomonas, and Priestia (one each). 59.4% of the strains were resistant to up to 4 antibiotics. The genera, listed from highest to lowest resistance to antibiotics, were Enterobacter (100% of its strains), Vibrio (70.6%), Staphylococcus (50%), and Bacillus (33.3%). The strains were most resistant to streptomycin (40.7%) and azithromycin (29.6%), antibiotics used exclusively in human clinical practice. Four strains of Vibrio spp., one of Staphylococcus epidermidis, and one of Enterobacter cloacae turned out multidrug–resistant. Most strains are potentially pathogenic and resistant to antibiotics, posing a risk to both crabs and consumers. Therefore, it is recommended to cook them thoroughly to eliminate the bacteria they harbor.