Antibiotic Resistance of Vibrio parahaemolyticus Isolated from Coastal Seawater and Sediment in Malaysia

Vibrio parahaemolyticus is widely recognized pathogenic Vibrio species due to numerous outbreaks and its wide occurrence in the marine environment. A total of 50 Vibrio parahaemolyticus isolates were isolated from seawater and sediments in Malaysia were tested for sensitivity to 19 antibiotics using disc diffusion method. It was found that all isolates were resistant towards ampicillin (10 mu g), penicillin (10 mu g), methicillin (5 mu g), and novobiocin (5 mu g); but exhibit sensitivity to chloramphenicol (30 mu g) and gentamicin (100 mu g). The low percentage of sensitivity towards antibiotics was observed with the following antibiotics; amoxicillin 10 mu g (98%), fluconazole 25 mu g (98%), erythromycin 15 mu g (92%), vancomycin 30 mu g (92%), bacitracin 10 mu g (84%), carbenicillin 100 mu g (84%), cephalothin 30 mu g (52%), nitrofurantion 200 mu g (52%), ciprofloxacin 5 mu g (40%), tetracycline 30 mu g (20%), kanamycin 30 mu g (10%), nalidixic acid 30 mu g (10%) and streptomycin 20 mu g (6%). Multiple antibiotic resistance (MAR) index was found to be 0.42-0.78. All the isolates were multi-resistant to these antibiotics. This indicates that the isolates originate from high-risk source of contamination where antibiotics are often used. Thus, there is a need for supervised use of antibiotics and frequent surveillance of V. parahaemolyticus strains for antimicrobial resistance. The presence of V. parahaemolyticus in coastal water with a high value of multiple antibiotic resistance indexes (MARI) can increase the risk of exposure to human and regular monitoring program for this potential human pathogenic bacterium is important.