Multi-Drug Resistance Genes associated with some Gram-Negative Bacteria Isolates from Shellfish in Iko and Douglas River Estuaries, in Nigeria

Background: Multi drug resistant bacterial agents that contaminate seafood cause several diseases in humans and are widely documented as a global public health challenge. Methods: This study evaluated the microbiological and antimicrobial resistance genes profiles of bacterial Isolates from shellfish vended at Iko and Douglas Creeks of Cross River State, Nigeria. A total of 540 shellfish (117 clams, 88 oysters, 136 periwinkles) samples were collected from various vendor at the two Creeks were analyzed. The samples were processed using standard microbiological methods to identify bacterial pathogens. Antimicrobial susceptibility was assayed using the Kirby-Bauer disk diffusion method. Isolates were screened for antimicrobial resistant genes using polymerase chain reaction. Results: Overall, a total of 135 bacteria isolates were identified. The most common isolate was Alcaligenes species 53(39.2%) followed by Pseudomonas species 44(32.6%), Providencia species 25(18.5%), Vibrio species 6(4.4%), and Paenalcaligenes species 7(5.2%). The isolates showed varying susceptibilities to Imipenem (36%) and amikacin (28%) but were all resistant to Trimethoprim-Sulfamethoxazole. Fifty-three isolates had a multiple antibiotic resistance index (MARI) of ≥0.9 - 1.0. Most of the bacterial isolates were detected with TEM genes (82.2%), SHV (51.8%,), VIM (50.3%) resistance genes. None of the isolates expressed Veb gene. Only 40.7% of the isolates expressed QnrB gene while none expressed QnrA and QnrS. Conclusion: The detection of these multidrug resistant clinically relevant bacterial species suggests a significant linkage of commonly consumed seafood in the community and environmental spread of MDR bacteria.