Characterization and Antibiotic Sensitivity Profile of Two Bacteria Isolated from a Marine Environment in Lagos State, Nigeria

Abstract

Background: Antimicrobial resistance (AMR) is a growing global health concern, posing a serious risk to public health and threatens to compromise the efficacy of antimicrobial treatments. Developing effective ways to address it requires an understanding of its mechanics, drivers, and consequences. Objectives: The present study was designed to identify, characterize, and assess the antibiotic susceptibility profiles of two bacteria isolated from marine water samples obtained from the Atlantic Ocean in Lagos, Nigeria. Methods: The two bacterial isolates from the marine water sample used in this study were obtained from stock cultures maintained on nutrient agar (NA) slants. These slants were sealed to prevent desiccation and stored at 4°C in the microbiology laboratory of the department. Pure, distinct colonies of the isolates were subcultured on NA and eosin methylene blue (EMB) plates and examined for their morphological characteristics. Gram staining and various important biochemical assays were performed, and antibiotic susceptibility was assessed using the Kirby-Bauer disk diffusion method Results: The two bacteria isolates were identified as Pseudomonas aeruginosa and Escherichia coli. Both were resistant to ampicillin (AMP), tetracycline (TET), and nitrofurantoin (NIT) but exhibited distinct morphological and biochemical traits. Conclusions: The presence of multi-drug resistant P. aeruginosa and E. coli. in the studied marine environment suggests that it may serve as a reservoir for AMR genes, highlighting the urgent need for local antimicrobial stewardship.