Antibiotic Susceptibility and Plasmid Profile of Vibrio Vulnificus Isolated from Mussels in Qatar

Abstract

Antibiotic Susceptibility and Plasmid Profile of Vibrio vulnificus isolated from mussels in Qatar Vibrio vulnificus infections are the worldwide public health problems associated with illnesses resulting from consumption of raw or partially cooked seafood and exposure with the contaminated sea water. Infections of V. vulnificus are reported in many different countries in America, Europe and Asia notably in USA, South Korea, Taiwan, Malaysia and Saudi Arabia. The aim of this study is to isolate and identify V. vulnificus from Mussels in Qatar and detect antibiotic susceptibility and plasmid profiles. A total of 87 Mussels, 50 from Doha and 37 from Akhor were examined for the presence of V. vulnificus using Thiosulfate-citrate-bile salts-sucrose agar (TCBS) and Chromagar Vibrio (CV), 18% of Doha samples were positive and 13.5% of Alkhor samples were positive, 9 of 14 isolates from Doha and 5 of 14 isolates from Alkhor. The antibiotic susceptibility tests were performed for 12 antibiotics by the disc diffusion method. For molecular identification of the isolates, the 16S ribosomal RNA gene fragment was amplified by polymerase chain reaction (PCR) and the nucleotide data were subjected to Basic Local Alignment Search Tool (BLAST) for analysis, Sequence comparison with public databases resulted in 96-100% similarity with V. vulnificus in 15 (60%), 99-100% similarity with V. paheamolyticus in 5 (20%); and 5 (20%), were identified as the non-vibrio species, The analysis of evolutionary relationships among isolates in this study was represented in seven cluster groups. The cluster A referred to non-vibrio isolates whereas the clusters B, C, E, F, and G included V. vulnificus. V. paraheamolyticus was only represented in the cluster D. 16S rDNA-based identification confirmed the conventional identification for isolates. The morphological and biochemical test detected V. vulnificus in 32% of the Mussels samples all of which showed resistance for two to eight antibiotics. Plasmids were found in 88% of the isolates with 10 different profiles having two to four plasmids. Based on 16S rRNA gene sequence homology 15 isolates were identified as V. vulnificus, five as other Vibrios and five as nonvibrios. We have observed a marked difference between morphological methods and molecular methods in identification of V. vulnificus indicating the in adequacy of the morphological technique in discriminating the Vibrio species. The occurrence of V. vulnificus in the Mussels samples is quite high so consumption of uncooked and semicooked Mussels should be avoided in order to prevent food-borne infection by this pathogenic bacterium. There are observed a marked difference between morphological methods and molecular methods in identification of V. vulnificus indicating the in adequacy of the morphological technique in discriminating the Vibrio species. The occurrence of V. vulnificus in the cockle samples is quite high so consumption of uncooked and semicooked cockles should be avoided in order to prevent food-borne infection by this pathogenic bacterium. Antibiotic susceptibility. Bacterial isolates showing resistance to more than six antibiotics contained more than three plasmids. Plasmids are known to carry antibiotic resistance genes. Otherwise, V. vulnificus isolates in which no plasmids could detected also has resistance to some of antibiotics, that mean antibiotic resistance genes may also be carried on the chromosome of bacteria.