title: Detection of the classical G2576U mutation in linezolid resistant Staphylococcus aureus along with isolation of linezolid resistant Enterococcus faecium from a patient on short-term linezolid therapy: first report from India.
abstract: OBJECTIVE
  Linezolid is an effective drug against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). We describe the emergence of linezolid resistance in MRSA and VRE from India.
  
  
  METHODS
  One MRSA and two VRE strains were isolated from a patient on linezolid therapy of one week duration. All three isolates were resistant to linezolid with minimal inhibitory concentrations (MIC) ≥4 mg/L. The 746-bp region flanking the possible G2576U mutation on the corresponding DNA from the 23S rRNA was amplified by polymerase chain reaction (PCR) and amplicons were sequenced for all the three isolates. Conjugation experiments using the linezolid resistant MRSA (LRMRSA) and linezolid resistant VRE (LRVRE) isolates as donors and wild strains of corresponding genera as recipients were performed.
  
  
  RESULTS
  The MRSA isolate had the classical G2576U mutation. High quality value scores in the sequencing software validated the mutation. Conjugation studies did not indicate presence of transferable resistance for linezolid. Sequencing did not indicate presence of any mutation in the two LRVRE isolates.
  
  
  CONCLUSIONS
  This is the first report from India citing resistance in Staphylococcus and Enterococcus against Linezolid.
authors.affiliation: Department of Microbiology , University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi, India.
authors.forename: S
authors.initials: S
authors.lastname: Rai
authors.forename: D K
authors.initials: DK
authors.lastname: Niranjan
authors.forename: T
authors.initials: T
authors.lastname: Kaur
authors.forename: N P
authors.initials: NP
authors.lastname: Singh
authors.forename: V
authors.initials: V
authors.lastname: Hada
authors.forename: I R
authors.initials: IR
authors.lastname: Kaur
mesh_terms: D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D016984:Enterococcus faecium / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D007194:India; D000069349:Linezolid / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D008826:Microbial Sensitivity Tests; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012338:RNA, Ribosomal, 23S; D000069349:Linezolid