Prevalence, Antibiotics Resistance and Plasmid Profiling of Vibrio spp. Isolated from Cultured Shrimp in Peninsular Malaysia

Abstract

<i>Vibrio</i> is the most common bacterium associated with diseases in crustaceans. Outbreaks of vibriosis pose a serious threat to shrimp production. Therefore, antibiotics are commonly used as preventative and therapeutic measures. Unfortunately, improper use of antibiotics leads to antibiotic resistance. Nevertheless, information on the occurrence of <i>Vibrio</i> spp. and antibiotic use in shrimp, particularly in Malaysia, is minimal. This study aimed to provide information on the occurrence of <i>Vibrio</i> spp., its status of antibiotic resistance and the plasmid profiles of <i>Vibrio</i> spp. isolated from cultured shrimp in Peninsular Malaysia. Shrimp were sampled from seven farms that were located in different geographical regions of Peninsular Malaysia. According to the observations, 85% of the shrimp were healthy, whereas 15% were unhealthy. Subsequently, 225 presumptive <i>Vibrio</i> isolates were subjected to biochemical tests and molecular detection using the <i>pyrH</i> gene. The isolates were also tested for antibiotic susceptibility against 16 antibiotics and were subjected to plasmid profiling. Eventually, 13 different <i>Vibrio</i> spp. were successfully isolated and characterized using the <i>pyrH</i> gene. They were the following: <i>V. parahaemolyticus</i> (55%), <i>V. communis</i> (9%)<i>, V. campbellii</i> (8%), <i>V. owensii</i> (7%), <i>V. rotiferianus</i> (5%), <i>Vibrio</i> spp. (4%), <i>V. alginolyticus</i> (3%), <i>V. brasiliensis</i> (2%), <i>V. natriegens</i> (2%), <i>V. xuii</i> (1%), <i>V. harveyi</i> (1%), <i>V. hepatarius</i> (0.4%) and <i>P. damselae</i> (3%). Antibiotic susceptibility profiles revealed that all isolates were resistant to penicillin G (100%), but susceptible to norfloxacin (96%). Furthermore, 16% of the isolates revealed MAR of less than 0.2, while 84% were greater than 0.2. A total of 125 isolates harbored plasmids with molecular weights between 1.0 and above 10 kb, detected among the resistant isolates. The resistant isolates were mediated by both chromosomal and plasmid factors. These findings support the use of surveillance data on the emerging patterns of antimicrobial-resistance and plasmid profiles of <i>Vibrio</i> spp. in shrimp farms. The findings from this study can be used to develop a better disease management strategy for shrimp farming.