Molecular Characterization and Detection of Antibiotic Resistance Genes in Pseudomonas Species Isolated from Tympanotonus fuscatus

Aim: This was carried out to characterize Pseudomonas species isolated from the West African Mud Creeper (Tympanotonus fuscatus) molecularly and as well detect the possible presence of inducible AmpC gene that mediates resistance to cephalosporins and most penicillins.

Sample: Tympanotonus fuscatus (West African Mud Creeper), a gastropod mollusc found in brackish waters of West Africa was used for the study.

Place and Duration of Study: This study was carried out between February and August 2019 at the Department of Microbiology, Rivers State University, Port Harcourt, Nigeria.

Methodology: Thirty two (32) Pseudomonas species were isolated and identified culturally from T. fuscatus. Pseudomonas species isolates were subjected to a group of ten (10) antibiotics using the Kirby-Bauer disc diffusion method and resistant isolates were screened molecularly for the presence of resistance gene (AmpC). AmpC screening was carried out in a step wise process of DNA extraction, quantification, amplification of ampC gene using appropriate primer and Agarose gel electrophoresis to reveal which DNA extracts had ampC genes amplified. The two most resistant isolates had their 16S rRNA sequenced, identified and were also profiled for plasmids by extracting plasmid DNA.

Results: Results revealed that 96.67% of isolates had MAR index greater than 0.2 indicating high a risk source of contamination where antibiotics are often used. Results also showed the presence of ampC gene in seven (7) out of the twelve (12) isolates screened for ampC gene. Molecular characterization via sequencing of the 16S rRNA gene of the two (2) most resistant isolates confirmed that both isolates were strains of Pseudomonas aeruginosa. Profiling of plasmids also revealed the presence of plasmid DNA of about 10 kilo base pairs in both isolates profiled.

Conclusion: This study has revealed the resistance ability of Pseudomonas and some reasons behind this resistance. Appropriate investigation into antimicrobial resistance is recommended for the administration of drugs for the treatment of food-mediated Pseudomonas infections.