Antibiotic Resistance Patterns of Bacteria Isolated from Seafoods Sold Around Rumuolumeni Metropolis, Rivers State, Nigeria

Abstract

There is an increasing concern on the rising trend of antimicrobial resistance (AMR) among bacterial isolates from seafood. The misuse and overuse of antibiotics in aquaculture, livestock farming, and human medicine have accelerated the emergence of multidrug-resistant (MDR) bacteria. Seafood constitutes an important source of animal protein and economic livelihood for residents of Rumuolumeni metropolis, Rivers State, Nigeria. However, increasing environmental pollution, unhygienic handling, and indiscriminate antimicrobial use pose risks of microbial contamination and antimicrobial resistance (AMR). This study investigated the bacteriological quality and antimicrobial susceptibility profiles of bacteria isolated from selected seafoods sold within Rumuolumeni metropolis. A total of four types of seafood samples, fish, prawns, crabs, and periwinkles, were randomly purchased from local vendors and analysed using standard microbiological techniques. Total heterotrophic bacterial count (THBC), total coliform count (TCC), fecal coliform count (FCC), and Salmonella–Shigella presence were determined. The findings revealed high bacterial contamination across samples, with THBC ranging from 7.51 ± 0.80 to 8.28 ± 0.96 Log10 CFU/g, exceeding recommended microbiological safety limits. TCC values were highest in prawns (8.23 ± 0.96 Log10 CFU/g), prawns had the highest SSC (4.67 ± 0.08 and 5.075 ± 0.01 Log10 CFU/g), while oyster had the lowest SSC (3.69 ± 0.13 and 4.55 ± 0.05 log₁₀ CFU/g), respectively. FCC recorded no detectable growth. Nineteen bacterial isolates were identified, dominated by Escherichia coli (32%), followed by Shigella spp. (16%), Salmonella spp. (16%), Pseudomonas spp. (16%), Proteus spp. (10%), and Enterobacter and Klebsiella spp. (5% each). All isolates exhibited multidrug resistance, with Multiple Antibiotic Resistance Index (MARI) values ranging from 0.3 to 0.8, indicating exposure to high-risk antibiotic-contaminated environments. High resistance was observed against ceftriaxone (100%), tetracycline (94.7%), and streptomycin (78.9%), while ciprofloxacin (100%) and ofloxacin (94.7%) showed the highest susceptibility. These findings highlight significant public health risks associated with the consumption of seafood from Rumuolumeni due to microbial contamination and multidrug-resistant pathogens. The study underscores the need for improved environmental sanitation, hygienic seafood handling, routine microbial surveillance, and strengthened antimicrobial stewardship to safeguard consumers’ health.