Characterization of Antibiotic Resistance Profiles of Ocular Enterobacteriaceae Isolates

Emergence of extended-spectrum β-lactamase (ESBL) and fluoroquinolone resistance among ocular Enterobacteriaceae is increasing in higher frequency. Therefore, studies are being carried out to understand their multidrug resistance pattern. A total of 101 Enterobacteriaceae isolates recovered from various ocular diseases in a tertiary eye care center at Chennai, India during the period of January 2011 to June 2014 were studied. Forty one randomly chosen isolates were subjected to antibiotic susceptibility by minimum inhibitory concentration (MIC) and genotypic analysis. Of them, 16 were ESBL producers, one was carbapenemase producer and four were resistant to ertapenem which could be due to porin loss associated with AmpC production, and 17 were resistant to fluoroquinolones. Sixteen isolates harbored ESBL genes in which 14 had more than one gene and none of them were positive for blaNDM-1 gene. QNR genes were detected in 18 isolates. ESBL producers were predominantly isolated from conjunctiva. A high degree of ESBL production and fluoroquinolone resistance is seen among the genus Klebsiella sp. Hence, monitoring the rate of ESBL prevalence plays a vital role in the administration of appropriate intravitreal antibiotics to save the vision and also to reduce the development of drug resistance in ocular pathogens.