130. Clinical Presentation and Molecular Epidemiology Characterization of Invasive GBS Infection in Nara, Japan from 2007 to 2016

Background Streptococcus agalactiae (GBS), a leading cause of neonatal infections, also occurs as an invasive infection in elderly people. The aim of this study was to evaluate the clinical aspect of invasive infections and the phenotypic and genetic diversity of GBS isolates to develop better antibiotics treatment and curb the increasing rate of antibiotic resistance in Nara, Japan. Methods GBS strains sequentially collected from blood and cerebrospinal fluid cultures between 2007 and 2016 were identified and evaluated for capsular types, multilocus sequence typing (MLST), antibiotic susceptibility, resistant gene, and pulsed-field gel electrophoresis (PFGE). Clinical characteristics were retrospectively collected. Results A total of 42 GBS isolates (12 from children and 30 from adults) were collected. In adults, common underlying conditions were malignancy and diabetes, and primary bacteremia was the most common source of infection. In children, 6 were early-onset diseases, 4 were late-onset diseases, and 2 were school children. Overall, the mortality rate was 0% in children and 17% in adults. The serotypes and main clonal complex are summarized in Table 1. Minimum inhibitory concentrations of the antibiotics were also determined (Table 2). The serotypes and resistant genes are shown in Table 3. PFGE revealed serotypes V and VI belonging to ST1, and serotype III belonging to ST335 were highly identical. Conclusion In clinical aspects, neonates with early-onset diseases experienced certain disorders during the perinatal period. In adults, serotype Ib, which tends to exhibit levofloxacin resistance, was the most common, followed by serotypes V and VI belonging to ST1; however, they were not observed in children. Contrastingly, serotype III belonging to ST335, which tends to exhibit macrolide resistance, was mainly observed in children. Quinolone among adults and macrolide among the younger generation are widely used as oral antibiotics in Japan. A tendency to use antibiotics affects bacterial flora and induces selectivity of specific clones, thereby causing diseases in the local community. Continuous surveillance is warranted in local areas for appropriate antibiotics treatment and prevent increasing antibiotic-resistant isolates. Disclosures All authors: No reported disclosures.