Vaginal & rectal carriage of Streptococcus agalactiae in the Czech Republic: incidence, serotypes distribution & susceptibility to antibiotics.

BACKGROUND & OBJECTIVES Streptococcus agalactiae (group B streptococcus, GBS) is the predominant bacterial agent responsible for invasive perinatal infection. To obtain reliable data on vaginal and rectal carriage of S. agalactiae in pregnant women in Czech Republic, and to formulate a prevention programme of neonatal GBS disease for the Czech Republic, women at childbirth were screened for vaginal and anorectal carriage of GBS. The isolates were serotyped and tested for susceptibility to antimicrobials including those recommended for intrapartum prophylaxis. METHODS A total of 586 women at childbirth were screened for GBS carriage in vaginal and anorectal regions using the non-enrichment and selective culture media. The isolates were serotyped by precipitation with antisera raised against various serotypes and antigenic extracts prepared according to Lancefield's modification. Mueller Hinton agar with 5 per cent defibrinated sheep blood was used for antimicrobial susceptibility testing. MIC values were evaluated according to the NCCLS criteria. RESULTS Using selective media, GBS was detected in 172 (29.3%) of 586 women screened, vaginal and anorectal colonization was found in 21.7 and 24.4 per cent of them, respectively, concomitant vaginal and anorectal colonization was recorded in 16.5 per cent of the women studied. Serotypes III (33.2%), Ia (22.0%) and V (13.9%) prevailed among 172 isolates tested. All isolates were susceptible to penicillin, ampicillin and cefotaxime. The rates of GBS resistance to tetracycline, erythromycin and clindamycin were 83.9, 3.8 and 3.2 per cent, respectively. INTERPRETATION & CONCLUSION GBS carriage in pregnant women in the Czech Republic is rather high as compared with that reported in literature. The most frequent serotypes III, Ia and V, identified in GBS-colonized pregnant women in the Czech Republic, were among those predominant in the USA and Western Europe. Our findings confirm uniform susceptibility of GBS isolates from pregnant women to penicillin and other beta-lactam antibiotics tested. Resistance to erythromycin remains low in the Czech Republic.