Clinical and microbiological characteristics of recurrent group B streptococcal infection among non-pregnant adults

•Recurrent GBS infections occurred more frequently than previously thought.•Recurrent GBS diseases occurred mainly in adults with a high comorbid index.•Relapse but not re-infection is the major cause for GBS disease recurrence.

SummaryObjectiveThis study aimed to investigate the clinical and microbiological features of recurrent group B streptococcal (GBS) diseases among non-pregnant adults.MethodsAll hospitalized non-pregnant adults who had culture-proven GBS infections between January 2008 and December 2010 were enrolled in this retrospective study. Bacterial isolates were examined for their serotypes, genotypes, and antimicrobial resistance.ResultsThe recurrence rate of GBS infection in Taiwan was found to be 9.3%. Of the 70 recurrent episodes in 32 patients, infections of the urinary tract (U) were diagnosed clinically in 55.7%, infections of the soft tissue (S) in 31.4%, and infections of the bloodstream (B) in 12.9%. The initial/recurrent episodes in 25 patients were mainly U/U (40.6%), followed by S/S (18.8%) and B/B (6.2%). The serotypes/serogroups identified were serotypes V (34.3%), Ib (22.9%), VI (17.1%), III (12.9%), IV (7.1%), and Ia (5.7%). Recurrent strains showed less resistance to erythromycin or clindamycin than non-recurrent strains. Six distinct genotypes were identified in 12 serotype VI isolates derived from seven patients; five of these isolate pairs had identical genotypes.ConclusionsRecurrent GBS diseases were found to occur considerably more often than previously thought, mainly in adults with a high comorbid index. Relapse, not new acquisition, was found to be more common.