Emergence of vancomycin-resistant Staphylococcus aureus identified in the Tlemcen university hospital (North-West Algeria).

INTRODUCTION Nosocomial infections are a matter of concern in surgical wards. Their incidence is constantly increasing, especially among immunocompromised patients who are vulnerable to colonization by opportunistic pathogens such as Staphylococcus aureus. The bacterium accumulates resistance mechanisms against antibiotics such as vancomycin. The objective of our study was to explore this resistance, to screen for Staphylococcus aureus strains resistant to vancomycin, and to try various antibiotic combinations against these strains. PATIENTS AND METHODS The antibiotic susceptibility of 220 S. aureus strains was determined by agar diffusion and evaluation of minimal inhibitory concentrations (MICs), by dilution technique on solid medium according to clinical and laboratory standard institute (CLSI) standards. The screening of strains resistant to vancomycin was performed on brain heart infusion agar medium, supplemented with 6μg/mL of vancomycin according to CLSI standards, and confirmed by determining MICs. The effectiveness of various antibiotic combinations was assessed by the checkerboard microplate method. RESULTS The results show multidrug resistance to agents known for their antistaphylococcal activity with fluctuations in the level of resistance. CONCLUSION Three strains proved resistant to vancomycin. The vancomycin/gentamycin combination was the most effective.