title: Molecular characterization of community- & hospital-acquired methicillin-resistant & methicillin-sensitive Staphylococcus aureus isolates in Sikkim.
abstract: OBJECTIVE
  The two major genotypic markers that distinguish community acquired (CA) from hospital acquired (HA) methicillin resistant Staphylococcus aureus (MRSA) isolates are the architecture of mobile genetic element (SCCmec type) and presence of panton valentine leukocidin (PVL) toxin. This study was conducted to determine the molecular characteristics of CA- and HA- MRSA and methicillin sensitive S. aureus (MSSA) isolates in Sikkim.
  
  
  METHODS
  A total of 150 clinical isolates of S. aureus isolated from various clinical specimens were subjected to duplex (mec-A and pvl gene) and multiplex (SCCmec typing) PCR.
  
  
  RESULTS
  Of the 150 isolates, 53 (35.33%) and 66 (44%) were positive for mec-A (MRSA) and pvl genes, respectively. Thirty eight (25.33%) met the definition of CA-MRSA and 15 (10%) of HA-MRSA and the remaining 63 (42%) and 34 (22.66%) as CA- and HA-MSSA, respectively. No significant difference was seen in the distribution of PVL toxin in MRSA and MSSA isolates, but it was significantly (P<0.001) high in overall MRSA isolates than in MSSA. The majority of the MRSA isolates showed a double amplification band of SCCmec type III plus V (54.71%), and only a fewer isolates were amplified by single DNA fragments of type I (1.88%), III (3.77%), IVa (1.88%) and V (11.32%). SCCmec types I, III, IVa, were found only in HA-MRSA isolates, whereas type V in both the CA- and HA-MRSA. AST pattern showed that 18.42 per cent (7/38) and 46.66 per cent (7/15) were multidrug resistant (MDR)-CA-MRSA and MDR-HA-MRSA, respectively.
  
  
  CONCLUSIONS
  The present results show that SCCmec type V MRSA has been on the rise, and genotypic markers such as pvl gene detection used for the differentiation of these clinically distinct isolates of MRSA may not be reliable.
authors.forename: Kunsang Ongmoo
authors.initials: KO
authors.lastname: Bhutia
authors.affiliation: Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Tadong, India.
authors.forename: Tsk
authors.initials: T
authors.lastname: Singh
authors.forename: Luna
authors.initials: L
authors.lastname: Adhikari
authors.forename: Shilpie
authors.initials: S
authors.lastname: Biswas
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000235:genetics* / Q000382:microbiology; D005098:Exotoxins / Q000235:genetics*; D006761:Hospitals; D006801:Humans; D020071:Interspersed Repetitive Sequences; D007956:Leukocidins / Q000235:genetics*; D008712:Methicillin / Q000627:therapeutic use; D016106:Methicillin Resistance / Q000235:genetics*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000472:pathogenicity; D008826:Microbial Sensitivity Tests; D046915:Penicillin-Binding Proteins / Q000235:genetics*; D012819:Sikkim; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000235:genetics* / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus; D008712:Methicillin