Science and Education Publishing American Journal of Epidemiology and Infectious Disease 1 4 2013 12 06 Increased Vancomycin Minimum Inhibitory Concentrations of Methicillin-Resistant Staphylococcus aureus Nosocomial Isolates in Southwestern Saudi Arabia 59 62 EN Ahmed Morad Asaad Department of Microbiology, College of Medicine, Najran University, Najran, Saudi Arabia Mohamed Ansar Qureshi AJEID2013146 10.12691/ajeid-1-4-6 2013 11 05 2013 11 26 2013 12 06 This study aimed to determine the distribution of vancomycin (VAN) MIC values and antimicrobial resistance patterns of MRSA nosocomial isolates from a Saudi tertiary care hospital and evaluate the presenting clinical and demographic features of different infections caused by these isolates. A total of 104 non-duplicating MRSA nosocomial strains were isolated. VAN MICs were determined by standard Etest and the Etest macromethod (MET). Among all isolates, 7.7% had a MIC = 2 µg/ml, 70.2% had a MIC = 1 µg/ml and 22.1% had a MIC = 0.5 µg/ml. No heterogeneous VAN-intermediate S. aureus (hVISA) were detected. Patients infected with high VAN MRSA nosocomial isolates were of significantly older age (p = 0.035), presented more often with bacteraemia (p = < 0.0001) and had longer hospital stays (p = < 0.0001). The presence of high VAN MICs of some MRSA isolates in our hospital is worrying and a cause for concern due to the possibility of the potential failure of treatment of these isolates. Moreover, accurate MIC testing using MET simultaneously or as a supplement to automated systems (i.e. Vitek) is important.