Molecular Characterization of Linezolid Resistance Among Staphylococcus Species In Tertiary Care Hospital

Abstract

Title: Molecular Characterization of Linezolid Resistance among Staphylococcus species in Tertiary Care Hospital newlineAuthor: KM. Sangita,1 Geeta Gupta,2 Anita Pandey,3 Ankita Gupta.4 newlineAffiliations: 1Ph.D Scholar, 2Department of Microbiology, Santosh Medical College and hospital (Santosh Deemed to be university) Ghaziabad U.P India and 3Department of Microbiology, Subharti Medical College, SVSU, Meerut U.P. newlineIntroduction: Linezolid is one of the last resort of antibiotics effectively used in the treatment of infections caused by multidrug resistant Gram positive bacteria. This study was carried out with the objective to detect the presence of cfr (chloramphenicol florfenicol resistance) and optrA (oxazolidinone phenicol resistance) gene in clinical isolates of linezolid resistant Staphylococcus species in a tertiary care hospital. newlineMaterials and Methods: This cross sectional study included clinical samples received in Microbiology laboratory from various inpatient units (IPD) and outpatient department (OPD) of the hospital. A total of 721 clinical isolates of Staphylococcus species; Staphylococcus aureus (199) and Coagulase negative staphylococcus (522) were identified using GP ID p628 card and antibiotic susceptibility was done using GPAST cards in Vitek 2C system (Biomerieux, France) to determine minimum inhibitory concentration (MIC) of linezolid. MIC of and#8805; 8 and#956;g/ml was taken as resistant. Further, presence of cfr and optrA gene was looked for in the clinical isolates of linezolid resistant S. aureus (LRSA) and linezolid resistant CoNS (LRCoNS) by polymerase chain reaction (PCR). newlineResults: Overall, resistance to linezolid was detected in 40 (5.5%) isolates of Staphylococcus species by phenotypic method, out of which 5 (2.5%) isolates was LRSA and 35 (6.7%) were LRCoNS. All the linezolid resistant isolates of Staphylococcus species were also methicillin resistant. On genotype based detection, cfr gene was detected in 2 (40%) isolates of LRSA and 25 (71.42%) isolates of LRCoNS. However, all the isolates of Staphylococcus species were negative for optrA gene. Conclusion: The presence of the cfr gene is the most common mechanism causing resistance to linezolid. Early and reliable identification of these isolates can prevent nosocomial horizontal transmission of this gene and help in improving the clinical outcomes. Key Words: Staphylococcus species, Linezolid resistance, Molecular detection, cfr and optrA gene. newline