Detection of a Novel G2603T Mutation in cfr Harboring Linezolid-Resistant : First Report from India.

has emerged as an important multidrug-resistant nosocomial pathogen. Linezolid is useful in the treatment of severe infections caused by methicillin-resistant . Resistance to linezolid in is due to one or more of the following mechanisms: acquisition of the (chloramphenicol florfenicol resistance) gene, mutation in the central loop of domain V of the 23S rRNA, and mutation in the and genes. This study was carried out to detect and characterize resistance to linezolid among the clinical isolates of .  The study included 84 clinical isolates of . Susceptibility to various antibiotics was determined by disc diffusion method. Minimum inhibitory concentration (MIC) was determined by agar dilution method for linezolid. Methicillin resistance was screened using oxacillin and cefoxitin disc. Polymerase chain reaction was done to detect and mutations in the V domain of the 23S rRNA gene.  Resistance to linezolid was exhibited by 3 of the 84 study isolates with MIC more than 128 µg/mL. The gene was detected in all the three isolates. The G2603T mutation was observed in the domain V of the 23S rRNA among two isolates, whereas one isolate lacked any mutation.  The emergence and spread of linezolid-resistant isolates carrying G2603T mutation in the domain V of the 23S rRNA and harboring the gene pose a threat in clinical practice.