title: Misidentification of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals in Tripoli, Libya.
abstract: BACKGROUND
  Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial (hospital-acquired) pathogen of exceptional concern. It is responsible for life-threatening infections in both the hospital and the community.
  
  
  OBJECTIVE
  To determine the frequency of MRSA misidentification in hospitals in Tripoli, Libya using current testing methods.
  
  
  METHODS
  One hundred and seventy S. aureus isolates previously identified as MRSA were obtained from three hospitals in Tripoli. All isolates were reidentified by culturing on mannitol salt agar, API 20 Staph System and retested for resistance to methicillin using the cefoxitin disk diffusion susceptibility test and PBP2a. D-tests and vancomycin E-tests (Van-E-tests) were also performed for vancomycin-resistant isolates.
  
  
  RESULTS
  Of the 170 isolates examined, 86 (51%) were confirmed as MRSA (i.e. 49% were misidentified as MRSA). Fifteen (17%) of the confirmed MRSA strains exhibited inducible clindamycin resistance. Of the 86 confirmed MRSA isolates, 13 (15%) were resistant to mupirocin, 53 (62%) were resistant to ciprofloxacin, 41 (48%) were resistant to trimethoprim-sulfamethoxazole, and none were resistant to linezolid. Although disc-diffusion testing indicated that 23 (27%) of the isolates were resistant to vancomycin, none of the isolates were vancomycin-resistant by Van-E-test.
  
  
  CONCLUSIONS
  Misidentification of nosocomial S. aureus as MRSA is a serious problem in Libyan hospitals. There is an urgent need for the proper training of microbiology laboratory technicians in standard antimicrobial susceptibility procedures and the implementation of quality control programs in microbiology laboratories of Libyan hospitals.
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Veterinary Medicine, Al Fateh University, Tripoli, Libya.
authors.forename: Mohamed O
authors.initials: MO
authors.lastname: Ahmed
authors.forename: Abdulbaset R
authors.initials: AR
authors.lastname: Abuzweda
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Alghazali
authors.forename: Asma K
authors.initials: AK
authors.lastname: Elramalli
authors.forename: Samira G
authors.initials: SG
authors.lastname: Amri
authors.forename: Ezzeddin Sh
authors.initials: ESh
authors.lastname: Aghila
authors.forename: Yousef M
authors.initials: YM
authors.lastname: Abouzeed