Detection of virulence and resistance genes in bacterial isolates from seafood obtained from Nembe and Ox-Bow Lake, Bayelsa State, Nigeria
Date
2019-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Federal University of Technology, Owerri
Abstract
Microorganisms have developed different mechanisms of evading the actions of antimicrobial agents, consequently, reducing the effectiveness of these antimicrobial agents. Antibiotics abuse and their use in animal husbandry have increased the acquisition and transfer of antibiotic resistant genes from and within the environment. This study is aimed at detecting resistance and virulence genes in bacterial isolates from seafood. A total of 200 fresh seafood samples (crab, shrimp, oyster and periwinkle) were collected randomly from Nembe River and Ox-bow Lake. Isolates were obtained using the conventional microbiological methods after an initial enrichment treatment in peptone for six (6) hours. The pure cultures were screened by gram staining and biochemical test for preliminary identification and representative isolates were characterized for 16SrRNA using Polymerase Chain Reaction and Sequencing. The isolates were further subjected to pathogenicity test to identify the presence of hemolysin and coagulase as well as antimicrobial susceptibility testing using standard oxoid commercial antibiotics. The 16srRNA sequence of the isolates produced an exact match during the mega blast search to Staphylococcus gallinarum, Vibrio rotiferianus, Vibrio parahaemolyticus, Klebsiella aerogenes and Klebsiella quasipneumoniae. All isolates showed resistance to ceftriazone, ceftazidime, ampicillin and penicillin. The multi-drug resistant isolates were analyzed for the presence of the resistance genes ctx-M, shv, mec A and acrAB as well as virulence genes; tdh and sxt. acrAB genes were detected in Klebsiella aerogenes and Klebsiella quasipneumoniae, the ctx-M was detected only in Klebsiella quasipneumoniae, the shv was detected in Klebsiella quasipneumoniae, Klebsiella aerogenes and Vibrio rotiferianus. The tdh genes were detected in Vibrio parahaemolyticus only. Staphylococcus gallinarum was positive for mecA genes. The presence of these Extended Spectrum β-Lactamases and other resistance genes explains why the isolates were resistant to the third generation cephalosporins as well as the β-lactam antibiotics. The presence of virulence gene, tdh in Vibrio sp codes for the virulence in these organisms therefore rendering the food unsafe for consumption. Adequate handling as well as proper cooking of seafood
before consumption should be highly recommended so as to reduce the incidence of food-borne infections as well as antibiotic resistance.
Description
This thesis is for the award of Masters of Science (M.Sc.) in Food and Industrial Microbiology
Keywords
Sea food, molecular characterization, antibiotic virulence genes, resistance genes, bacterial isolates, multi-drug resistance, Department of Microbiology
Citation
Justice-Alucho, C. H. (2023). Detection of virulence and resistance genes in bacterial isolates from seafood obtained from Nembe and Ox-Bow Lake, Bayelsa State, Nigeria (Unpublished Master's Thesis). Federal Universty of Technology, Owerri, Nigeria