Background: Streptococcus agalactiae infection in nonpregnant adults is an emerging disease with increasing burden. This study described epidemiologic, clinical characteristics, and treatment options among patients with S. agalactiae bacteremia, and determined the factors associated with mortality.
Methods: Medical records from all adult patients with S. agalactiae isolated from blood cultures from 2006 to 2016 were retrospectively reviewed. Patients, who had mixed bacteremia, were transferred to other hospitals, or missing records were excluded from the study.
Results: During the study period, S. agalactiae was isolated from 282 individuals. Increasing trend was observed, with peak incidence from May to July. Study criteria were met among 238 patients. Most patients (64%) had underlying medical conditions, with diabetes as the most common disease, followed by malignancy, chronic kidney disease and alcoholism. The most common manifestations were primary bacteremia, followed by arthritis, cellulitis, meningitis, osteomyelitis and endocarditis. Three patients had transient bacteremia. Thirty-day mortality was 16.4%, with age of ≥65 years, alteration of consciousness, absence of fever, high Pitt bacteremia score (≥4) and shock, as associating factors on univariate analysis. In a subgroup of patients with prolonged intravenous antibiotic, penicillin G treatment was identified as a protective factor against mortality. Multivariate analysis found independent associating factors of 30-day mortality were high Pitt bacteremia score and absence of fever.
Conclusion: S. agalactiae bacteremia in nonpregnant adults showed an increasing trend. High mortality was observed, especially among those with severe clinical manifestations at presentation. Penicillin G is still the drug of choice for the definite intravenous treatment.
Keywords: Bacteremia; Group B Streptococcus; Penicillin; Streptococcus agalactiae.
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