Antibiogram and molecular characterization of biofilm producing bacteria isolated from service water in tertiary hospitals in Rivers State

Abstract

Hospital service water can harbor biofilm-producing bacteria, posing significant health risks, especially in tertiary healthcare settings where patients are vulnerable to waterborne infections. These bacteria contribute to biofilm formation, persistent infections, and antibiotic resistance. In Rivers State, Nigeria, maintaining water quality in tertiary hospitals is challenging, necessitating the investigation of biofilm-producing bacteria to improve water management and reduce infections. This study aimed to identify biofilm-producing bacteria in hospital water, assess their antibiotic resistance, and explore the genetic mechanisms underlying their resistance. Over three months, 135 water samples were collected from strategic locations, including the water source, operating theaters, wards, and laboratories. Samples were aseptically collected, preserved at 4°C, and analyzed using biochemical tests, antibiotic susceptibility profiling, biofilm formation assays, and molecular characterization. Twelve bacterial genera were identified, including three Gram-positive species (Staphylococcus, Bacillus, and Enterococcus) and nine Gram-negative genera (Escherichia, Proteus, Salmonella, Enterobacter, Pseudomonas, Serratia, Shigella, Klebsiella, and Providencia). Biofilm production was highest in Shigella, Staphylococcus, Bacillus, Escherichia coli, Pseudomonas, and Salmonella (100%), while Providencia (90%) and Klebsiella (37.5%) had lower rates. Molecular analysis revealed ten isolates with 96–100% genetic similarity, including Shigella sonnei, Escherichia coli (ETEC), Pseudomonas aeruginosa, Proteus mirabilis, and Salmonella enterica. Antibiotic susceptibility varied, with resistance to multiple antibiotic groups. Ofloxacin and Nitrofurantoin showed effectiveness against some isolates. This study confirms the presence of biofilm-producing, antibiotic-resistant bacteria in hospital water systems. It emphasizes the need for improved aseptic practices, plumbing maintenance, and regular water treatment to enhance water quality and prevent waterborne infections in tertiary hospitals.

Keywords: Service water, biofilm producing bacteria, resistance, antibiotics.