ANTIMICROBIAL SUSCEPTIBILITY AND PREVALENCE OF EXTENDED SPECTRUM BETALACTAMASE (ESBL) AND METALLO BETALACTAMASE (MBL) AND ITS CO-EXISTENCE AMONG PSEUDOMONAS AERUGINOSA RECOVERED FROM OCULAR INFECTIONS

Objectives: To evaluate the changing trends in antimicrobial susceptibility rate and detection of ESBL and MBL among Pseudomonas aeruginosa isolated from various ocular infections over a 2 year periods with special reference to detection of ESBL and MBL co-existence among P aeruginosa recovered from ocular infections.Methods: All ocular specimens, culture positive for P aeruginosa (n=110) isolated from clinically suspected patients were submitted to L &T Microbiology Research Centre, Chennai, Tamil Nadu, India. Culture, antimicrobial susceptibility testing and ESBL detection was performed by Standard methods. MBL production was screened by Carbapenem-EDTA combination disk method.Results: Of the 3247 samples subjected to culture from August 2012– July 2014 by standard method 276 were positive for bacterial growth, thereby 8.5% of ocular infections mediated by bacterial pathogens. Out of 276 culture positives 110 (39.8%) Pseudomonas aeruginosa isolates recovered from ocular infections. The resistance rate for commonly used drugs against ocular infection includes Gentamycin [23.63%], Gatifloxacin [20.9%], Moxifloxacin [20%], Tobramycin [20%], ciprofloxacin [19.09%]. Totally 15 (13.63%) out of 110 isolates were identified as ESBL producer and 11 (10%) out of 110 isolates were identified as MBL producer by screening test, including 7 isolates have co-produced both ESBL and MBL enzymes and 4 isolates were only positive for MBL production.Conclusion: Though fluoroquinolones remains a good choice for ocular Pseudomonal infection. Gradual emergence of resistance to fluoroquinolones and aminoglycosides also noted from this study. The emergence of ESBL, MBL and pandrug resistance among P aeruginosa from ocular infections is an alarm rational finding which necessitates the earlier detection of both ESBL and MBL production as individual or co-existence in ocular isolates, which may pave the way for appropriate therapy for sight threatening conditions like endophthalmitis.Â