RPFF, SPGM AND RMLA GENES AND ITS BIOFILM FORMING ABILITY IN STENOTROPHOMONAS MALTOPHILIA

Abstract

Objectives: Purpose of this study to evaluate antimicrobial profile, association between biofilm formation & biofilm encoding genes among Stenotrophomonas maltophilia isolates from various clinical specimens. Methods: A total of 73 clinical isolates of Stenotrophomonas maltophilia were isolated from  non-fermentative Gram-negative bacilli from various clinical samples & were identified by VITEK-2 Compact System, Antimicrobial susceptibility testing was done by VITEK-2 compact system & by Kirby Bauer disc diffusion method/ E-test as per CLSI guidelines. Detection of biofilm formation was done by Modified Hucker crystal violet staining method and biofilm encoding genes were detected by PCR. Result: Antimicrobial susceptibility testing demonstrated that minocycline exhibited the highest activity (90.4% susceptibility), followed by levofloxacin (76.7%) & ticarcillin-clavulanic acid (75.3%). However, high resistance rates were observed against imipenem & meropenem (100% each), chloramphenicol (80.8%), ceftazidime (72.6%), tetracycline (71.2%), and ceftazidime-avibactam (63.1%). Biofilm formation was detected in all isolates (100%), indicating that biofilm production is a common virulence trait among clinical S. maltophilia strains. Among the isolates, 35.6% were weak biofilm producers, 47.9% were moderate producers, and 16.4% were strong biofilm producers. Among the 73 S. maltophilia isolates, the rpfF gene was detected in 48 (65.7%) isolates, spgM in 44 (60.3%) isolates, and rmlA in 45 (61.6%) isolates. Conclusion: Antimicrobial resistance and biofilm formation may work together to enhance the persistence and treatment challenges of S. maltophilia. Early identification, appropriate antimicrobial susceptibility testing, and better understanding of biofilm-associated mechanisms are important for effective management of infections caused by this emerging pathogen.