Impact of Bacterial Contamination and Antibiotic Resistance on the Quality of Giant Tiger Prawns (Penaeus monodon) from Vishakhapatnam Harbour, India

Introduction: Spoilage of Penaeus monodon, a commercially significant species, is a major concern due to its negative impact on the seafood industry and public health. The microbial contamination of shrimp, especially from harbor environments, can reduce product quality and pose food safety risks. This study aims to identify the bacterial species responsible for the spoilage of P. monodon sourced from Visakhapatnam Harbour, with an emphasis on their antibiotic resistance profiles. Methods: Bacterial isolates were obtained from the surface of P. monodon shrimp collected from Visakhapatnam Harbour. The total bacterial count was determined by serial dilution and plating on selective media, resulting in a bacterial count of 1.0602 × 104 CFU/g. Gram staining and biochemical tests were conducted on five isolated strains (M1, M2, M3, M4, M5) to determine their morphological characteristics and identify the species. Antibiotic susceptibility testing was performed to assess resistance profiles. Results: All five bacterial isolates were found to be Gram-negative. The isolates were identified as follows: M1 – Enterobacteria spp., M2 – Achromobacter spp., M3 – Vibrio spp., M4 – Pseudomonas spp., and M5 – Vibrio parahaemolyticus. The total bacterial count for the shrimp samples was 1.0602 × 104 CFU/g. Antibiotic resistance testing revealed significant resistance, particularly against ampicillin and penicillin G. Discussion: The presence of Vibrio and Pseudomonas, which are known to contribute to seafood spoilage, aligns with previous studies (Zhang et al., 2024). The antibiotic resistance observed in the isolates, particularly to commonly used antibiotics such as ampicillin, is concerning and reflects global challenges in controlling antibiotic-resistant pathogens in marine environments (Riaz et al., 2024). These findings underscore the need for effective preservation techniques and stricter regulations to ensure food safety and extend the shelf life of P. monodon.