Co-selection of antibiotic and disinfectant resistance in environmental bacteria: Health implications and mitigation strategies.

Background: The rapid emergence of co-selection between antimicrobials, including antibiotics and disinfectants, presents a significant challenge to healthcare systems. This phenomenon exacerbates contamination risks and limits the effectiveness of strategies to combat antibiotic resistance in clinical settings. This study aimed to investigate the prevalence and characteristics of bacteria in hospital environments that exhibit co-selection mechanisms and their potential implications for patient health, framed within the One Health perspective.

Methods: Air and surface samples were collected from seven large hospitals and analyzed to detect antibiotic-resistant bacteria (ARB). The resistance profiles of isolated ARB to various disinfectants were determined. Bacterial species were identified using 16S rRNA gene sequencing, and the presence of antibiotic resistance genes (ARGs) and class 1 integrons (intI1) was investigated.

Results: A high percentage (85%) of samples contained ARB, with β-lactam resistance being the most frequently observed. Alarmingly, 94% of isolated ARB exhibited resistance to at least one disinfectant, and 91% demonstrated resistance to three or more disinfectants. Staphylococcus and Bacillus emerged as the dominant genera displaying co-selection. The presence of ARGs, including mecA (associated with methicillin resistance) and qacB (associated with disinfectant resistance), along with intI1, provided further evidence supporting co-selection mechanisms.

Conclusion: These findings underscore the critical need for robust antimicrobial resistance surveillance and the prudent use of disinfectants in healthcare settings. Further research into co-selection mechanisms is essential to inform the development of effective infection control strategies and minimize the spread of resistant bacteria.