E.J. Giamarellos-Bourboulis, J. Zelenitsas, J. Stefanou,
G. Chrysos, P. Gargalianos, J. Kosmidis

Aids Unit, Athens General Hospital “G. Gennimatas”,
Greece.

SA is a common pathogen in bacterial infections of HIV(+) ind. Our purpose was to evaluate its rate of isolation in 110 HIV(+) ind and its susceptibility patterns. Nasal swabs were plated onto Chapman’s medium at 30°C and methicillin-resistance (MR) was determined by plating single colonies onto Mueller-Hinton agar supplemented with 1 μg/ml oxacillin and 2% NaCl. MICs were performed by a microdilution technique with a 5×10⁵ cfu/ml log-phase inoculum.

SA was isolated in 34 (30.9%) ind, 18 (52.9%) being MRSA, and in 10 out of 27 (37.1%) with acute sinusitis, as well as in 16 out of 38 (42.1%) C₃ category AIDS patients. Among the MRSA population 18 (100%), 10 (55.6%), 9 (50%), 9 (50%), 9 (50%), 7 (38.9%), 4 (22.2%) and 3 (16.7%) strains were susceptible to vancomycin, sparfloxacin, levofloxacin, rifampin, imipenem, clindamycin, erythromycin and ciprofloxacin respectively.

MIC₅₀–MIC₉₀ to the above agents were 1–1, 0.5–16, 1–8, 1–≥4, 0.5–≥32, 8–≥16, ≥16–≥16 and ≥4–≥4 μg/ml respectively.

It is concluded that SA is a common constituent of the normal flora of HIV(+) ind, and that 50% of MRSA isolates are susceptible to newer quinolones.