Multidrug-resistant pneumococci (serotype 8) causing invasive disease in HIV+ patients

From July 2007 to June 2009, all pneumococci causing invasive pneumococcal disease in our hospital were serotyped. Antimicrobial susceptibility was determined by microdilution. Molecular typing was performed by pulsed-field gel electrophoresis and by multilocus sequence typing. Among 251 invasive pneumococci, serotype 8 was the most frequent (13.5%). All serotype 8 strains were susceptible to penicillin; however, 61.8% (21/34) were co-resistant to erythromycin, levofloxacin and tetracycline and identical to the Sweden15A-ST63 clone. Serotype 8 was significantly more frequent among human immunodeficiency virus (HIV)-infected patients (36.5%). The high prevalence of this nonconjugate vaccine multiresistant serotype 8 is a cause for concern mainly in HIV-infected patients.