Prevalence of antibiotic-resistant toxic metal-tolerant and biofilm-forming bacteria in hospital surroundings

摘要

The emergence and rapid spread of antibiotic-resistant bacteria due to unethical and non-scientific disposal of hospital wastes and clinical by-products caused an alarming environmental concern and associated public health risks. The present study aims to assess the co-selection of antibiotic resistance and heavy metal tolerance by bacteria isolated from hospital effluents. These isolates were also tested for hemolytic activity, pH-tolerance, thermal inactivation, auto-aggregation, cell-surface hydrophobicity and interaction with other bacteria. The study reports the prevalence of antibiotic-resistant and heavy metal tolerant bacteria in clinical effluents and water samples. Most of these isolates were resistant to vancomycin, clindamycin, ampicillin, rifampicin, penicillin-G, methicillin and cefdinir, and evidenced the production of extended-spectrum β-lactamase enzyme. Toxic metals such as cadmium, copper, iron, lead and zinc also exert a selection pressure towards antibiotic resistance. Pseudomonas aeruginosa strain GCC_19W3, Bacillus sp. strain GCC_19S2 and Achromobacter spanius strain GCC_SB1 showed β-hemolysis, evidenced by the complete breakdown of the red blood cells. Highest auto-aggregation was exhibited by Bacillus sp. strain GCC_19S2; whereas, maximum cell-surface hydrophobicity was displayed by P. aeruginosa strain GCC_19W1. Antagonistic activity by Stenotrophomonas maltophilia strain GCC_19W2, P. aeruginosa strain GCC_19W3 and strains of Achromobacter restricts the growth of other microorganisms by producing some bactericidal substances. The study emphasises undertaking safety measures for the disposal of clinical effluents directly into the environment. The study suggests adopting necessary measures and regulations to restrict the spread of emerging pathogens within the hospital biome and community, which if unnoticed, might pose a significant clinical challenge.