Multidrug-resistant pneumococci (serotype 8) causing invasive disease in HIV plus 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 Sweden(15A)-ST63 clone. Serotype 8 was significantly more frequent among human immunodeficiency virus (HIV)-infected patients (36.5%). The high prevalence of this non-conjugate vaccine multiresistant serotype 8 is a cause for concern mainly in HIV-infected patients.