Antibiotic Susceptibility of Coliform and Vibrio Species in Shellfishes from Estuary Chronically Contaminated with Polycyclic Aromatic Hydrocarbon

Abstract

Polycyclic aromatic hydrocarbon (PAH) levels and antibiotic susceptibility of coliform and Vibrio species in swimming crab (Callinectes latimanus), mangrove oyster (Crassostrea tulipa), and periwinkle (Tympanotonus fuscatus) from Qua Iboe River and Cross River estuaries were assessed using standard procedures. Bacterial load in the shellfishes and surface water was 1.2 to 1.4 times higher than the control, but the difference was significant at p = 0.05. Total PAH level of 11.36 ± 0.3 mg kg^-1 in C. latimanus, 17.57 ± 0.9 mg kg^-1 in C. tulipa, and 13.88 ± 0.5 mg kg^-1 in T. fuscatus compared to 7.51 ± 0.3 mg L^-1 in the surface water and indicates 1.06 to 1.57 times higher PAH accumulation than in surface water and was significant (p = 0.05). The dominant coliform and Vibrio species in the shellfishes were Serratia marcescens, Enterobacter aerogenes, Escherichia coli, Klebsiella, Citrobacter diversus, and Vibrio alginolyticus, V. estuarianus, V. fischeri, V. fluvialis and V. parahaemolyticus. A mean of 21.2% difference between two study groups indicates that shellfishes were the main source of gastrointestinal illness with 43% median resistance to commercially available antibiotics. Accumulation of PAH and abundance of an emerging multiple antibiotic resistant bacterial strains is a cause of concern and potential health risk to consumers of the shellfishes.

Keywords: Shellfish, coliform, Vibrio, polycyclic aromatic hydrocarbon, antibiotic resistance