Antimicrobial resistance patterns reveal widespread multidrug-resistance among Vibrio species in shrimp hatchery environments of Bangladesh

Vibrio species are ubiquitous in shrimp hatchery systems, where their opportunistic pathogenic characteristics threaten the vulnerable larval stage, and antibiotics are routinely applied for disease control and prevention. Therefore, studying Vibrio composition and its antibiotic resistance burden is critical for hatchery environments and public health. The present study characterized Vibrio composition and its antimicrobial resistance patterns in water-flow systems and postlarvae from shrimp hatcheries in Coxs Bazar, Bangladesh. The findings revealed that Vibrio composition in these hatchery systems comprised nineteen different species. The Harveyi clade was the most dominant group, including V. alginolyticus, V. rotiferianus, and V. harveyi. The Vibrio isolates were highly resistant to erythromycin, ampicillin, and streptomycin, while remaining susceptible to chloramphenicol, nitrofurantoin, and gentamicin. Seven antibiotics, including trimethoprim-sulfamethoxazole, ampicillin, and erythromycin, were categorized as poorly active, suggesting their inefficacy against vibriosis outbreaks. More than 50% of the isolates had multiple antibiotic resistance index greater than 0.2 and 67.8% were categorized as multidrug-resistant. Both indices progressively increased along the water-flow systems and postlarvae had the highest values, pointing to antibiotic contamination within hatchery systems. Resistance gene screening identified sul2 and tetC as most prevalent, while association analysis showed cross-resistance patterns among antibiotics, concordance between trimethoprim-sulfamethoxazole and streptomycin resistance with the presence of sul2 and strA-strB genes, and co-selection of sul2, ermB, and strA-strB genes. The findings provide baseline data on Vibrio diversity and resistance burden, and inform antibiotic stewardship policies and monitoring strategies that support a One Health approach in shrimp hatchery systems.