Article Text

other Versions

PDF
Molecular characterisation of methicillin-resistant Staphylococcus aureus (MRSA) from keratitis patients: a microbiological analysis
  1. Mohd A Khan1,2,
  2. S Ahmad1,
  3. N Banu2
  1. 1Institute of Ophthalmology, Jawaharlal Nehru Medical College, Faculty of Medicine, Aligarh Muslim University, Aligarh, India
  2. 2Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, India
  1. Correspondence to Professor Naheed Banu, Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202001, India; naheedbanu7{at}yahoo.com

Abstract

Background In order to diagnose and characterise a major corneal infection, ‘keratitis,’ which can lead to blindness, molecular studies were conducted to assess the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in patients suffering from keratitis

Methods The selected culture positive for strains of S aureus were subjected to 18 antimicrobial drugs for their sensitivity behaviour, and the minimum inhibitory concentration (MIC) of oxacillin was determined by the microdilution method as recommended by the National Committee for Clinical Laboratory Standards. Further, S strains were characterised using molecular tools.

Results Among the 202 cases included in the present study, 64 (31.2%) cases were found to be S aureus-positive, of which only six strains were MRSA. The highest resistance was observed for penicillin (65.6%) which was followed by a significant number of bacterial isolates showing resistance to methicillin (9.3%), while all organisms were susceptible to vancomycin. The minimum inhibitory concentrations of oxacillin for MRSA strains ranged between 16 and 128 μg/ml. A multiplex PCR assay for Staphylococcal Cassette Chromosome mec complex (SCCmec) of MRSA strains (N=6) showed that five MRSA strains had a Type III cassette, and one had a Type II cassette. The pulsed field gel electrophoresis of three MRSA strains showed closely related band patterns.

Conclusion The close relatedness among bacterial strains as observed by employing different typing techniques suggests that the clonal characteristics of multiresistant MRSA isolates could be deciphered. The presence of Type II SCCmec in keratitis subjects is probably the first report from India, as it has not been reported earlier.

  • MRSA
  • SCCmec type II cassette
  • keratitis PFGE
  • infection
  • epidemiology
  • biochemistry
  • microbiology
  • genetics
  • infection

Statistics from Altmetric.com

Footnotes

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.