This is the largest Libyan study to date to investigate the prevalence and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) among health care workers in Tripoli, Libya. A total of 569 doctors and nurses from 4 main hospitals were screened for MRSA with specimens collected from the anterior nares. Isolates from 109 of the 569 subjects (19%) were confirmed as MRSA by polymerase chain reaction assay; the majority (98/109) were from a general hospital. Antimicrobial resistance patterns tested by disk diffusion were as follows: erythromycin (74%), ciprofloxacin (77%), clindamycin (20%), trimethoprim/sulfamethoxazole (50%), quinuprisin/dalfopristin (19%), vancomycin (12%) and mupirocin (5%). Eighteen isolates exhibited macrolide-lincosamide-streptogramin B resistance (MLSB): 6 were MLSBi and 12 were MLSBc. The results provide evidence that Libyan health care workers could serve as MRSA carriers and play a role in the dissemination of MRSA to the public and other workers.

BackgroundMethicillin-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.AimsTo determine the frequency of MRSA misidentification in hospitals in Tripoli, Libya using current testing methods.MethodsOne 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.ResultsOf 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.ConclusionsMisidentification 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.

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A collection of 94 Gram-negative bacteria isolates, showing different antimicrobial resistance phenotypes including to the carbapenem classes was investigated. Strains were originated form clinical sources from a single hospital in Tripoli, Libya during 2015 and were identified based on cultural and phenotypic characteristics, and fully characterized by the VITEK automated system. Forty-eight percent (48%) of the collection was identified as Acinetobacter baumannii, 50% Klebsiella pneumoniae and 2% Escherichia coli. Resistance to the carbapenem classes was reported in 96% of the A. baumannii strains and 94% of the K. pneumonia strains. Seventy-eight percent (78%) of the isolates showed different multidrug-resistant (MDR) phenotypes, of which K. pneumoniae expressing the highest rates of MDRs(i.e. 91%). Emergence of resistance to carbapenems in the Gram-negative bacteria is a challenging global problem, particularly for Africa. Surveillance of these pathogens and appropriate actions are urgently required in Libyan healthcare settings.

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