Prevalence of quorum sensing luxS gene in multidrug resistant uropathogens

The increasing prevalence of antimicrobial resistance (AMR) among urinary tract infections (UTIs) is making clinical management challenging. Biofilm formation is a key mechanism contributing to antibiotic resistance in uropathogens. Quorum sensing is known to regulate several bacterial processes like bioluminescence, virulence, and biofilm formation which is known to play a role in the development of drug resistance. Out of three major quorum sensing systems, luxS/AI-2 is a universal system used by both Gram-positive and Gram-negative bacteria.

Community-acquired AMR UTI isolates were analyzed for bacterial species distribution and antibiotic susceptibility patterns. Phenotypic biofilm formation was assessed using Congo Red Agar (CRA) method. The presence of luxS gene, associated with the AI-2 quorum sensing system, was determined by polymerase chain reaction (PCR).

Eight different bacterial species were identified, with Escherichia coli (44.1%) being the most prevalent, followed by Klebsiella spp. (27.9%). More than 90% of the isolates were resistant to at least 3 antibiotics and resistance to ampicillin was most common (67.6%), followed by cefazolin (54.4%), amoxyclav (53.4%), aztreonam (52.9%), and ciprofloxacin (48.52%). Phenotypic biofilm formation was observed in 35.29% of the AMR isolates which produced characteristic black colonies. However, luxS gene was detected in 91.17% of these AMR isolates.

Higher prevalence of luxS gene in AMR isolates indicate a strong association of quorum sensing potential with development of multidrug resistance. Targeting quorum sensing pathways may represent potential adjunct therapy alongside antibiotics for efficient clinical management of multidrug resistant UTI cases.