Screening for Resistant Genes and Plasmid Curing Profile Reagent of Salmonella enterica and Listeria monocytogenes from Seafood Sold in Rivers State, Nigeria

Preamble: Plasmid curing has been a successful technique in reducing resistant bacteria and controlling antibiotic resistance which promote pathogenicity of an organism.

Aim: This study is focused on screening resistant genes and plasmid curing profile reagent of Salmonella enterica and Listeria monocytogenes from seafood sold in Rivers State, Nigeria.

Study Design: A completely randomized design was used for the study and the work run from June 2023 to December 2023.

Methodology: A total of one hundred and twenty-six (126) raw and parboiled samples of Crassostrea gasar (Oyster) (42), Buccinum undatum (Whelks) (42) and Panaeus monodon (Prawn) (42) were purchased from three (3) Local Government Area markets and subjected to standard conventional methods such as culturing, isolation and identification using PALCAM agar (for Listeria monocytogenes) and Triple sugar iron test ( for Salmonella enterica), molecular screening using polymerase chain reaction and plasmid curing using an intercalating agent (acridine orange).

Results: The bacterial isolates were identified using molecular technique as: Salmonella enterica-AM04528, Salmonella bongori-NCTC12419, Salmonella enterica-KKP3882, Listeria ivanovii-PM-44, Listeria monocytogenes-HN1, Listeria monocytogenes-F6540, Salmonella enterica-19_85, Salmonella enterica-KKP1761, Listeria monocytogenes-NITRR/R1, Salmonella enterica-777SA01, Listeria monocytogenes-HR27 and Listeria monocytogenes-FC3. The resistant genes were present as blaTEM (58.33%) and blaSHV (91.67%) in Salmonella enterica and L. monocytogenes isolates. Plasmid curing with Acridine orange (An intercalating agent) reversed the resistant trait (100%) in the twelve (12) most resistant Salmonella enterica and L. monocytogenes isolates after susceptibility testing.

Conclusion: This study provides valuable insight into the genetic mechanism of antibiotic resistance of the two pathogens and highlights the potential of plasmid curing as a therapeutic approach and proper management of seafood.