Objectives To determine the incidence of invasive Group B streptococcal (iGBS) diseases and the factors significantly associated with iGBS mortality in adult patients. Material and methods This retrospective study included adults with a positive culture for GBS isolated from a sterile site at Siriraj Hospital – Thailand’s largest tertiary care hospital – during January 2013 to December 2017. Results Of the 224 included patients, 75.9% had bacteraemia. The median age of patients was 63 years (interquartile range [IQR]: 53–73) and 52.7% were female. Among the 80% of all patients with comorbid diseases, diabetes mellitus (38.8%), cancer (18.8%), and heart disease (12.5%) were the most common. Skin and soft tissue infection (30.8%), septic arthritis (21.4%), primary bacteraemia (21.0%), and meningitis (7.1%) were the most common manifestations of iGBS diseases. The overall 30-day mortality was 11%. Patients that died were older and had more chronic kidney disease, bacteraemia, urinary tract infection, pneumonia, and iGBS-related morbidities than survivors. Pneumonia was the only factor independently associated with 30-day mortality with an adjusted odds ratio of 24.96 (95% confidence interval [CI]: 5.95–104.75). Conclusions Invasive GBS is not uncommon in non-pregnant adults, particularly among older adults and those with diabetes. Concomitant bacteraemia was frequently observed in iGBS patients. The overall mortality was low, but significant morbidities were observed. KEY MESSAGES In our study, iGBS was not uncommon among older adults and those with diabetes. Two-thirds of patients with iGBS had bacteraemia, and the overall 30-day mortality was 11%.

BackgroundGroup B Streptococcus (GBS) has been increasingly associated with invasive diseases in nonpregnant adults. This study aims to describe the epidemiology of invasive GBS (iGBS) diseases in adult patients.MethodsA retrospective cohort study was conducted at Siriraj Hospital between January 1, 2013 and December 31, 2017. We included adult patients with a positive culture of GBS isolated from sterile sites.ResultsAmong 224 patients recruited to the study, 170 patients (75.9%) had bacteremia. The median age of all patients was 63 years (IQR 53–73 years) and 52.7% were female. Approximately 80% of all patients had comorbid diseases. Diabetes mellitus (38.8%), cancer (18.8%) and heart disease (12.5%) were the three most common comorbidities. Skin and soft-tissue infection (30.8%), septic arthritis (21.4%), primary bacteremia (21%), and meningitis (7.1%) were the four most common presenting syndrome of iGBS diseases. Overall mortality within 30 days of infection was 12%. Non-survived patients were older, had chronic kidney disease, bacteremia, pneumonia and had at least one comorbidity than survived patients. However, only pneumonia was found independently associated with the 30-day overall mortality, with adjusted odd ratio (aOR) of 24.96 (95% confidence interval [CI]: 5.95–104.75). Antimicrobial susceptibility testing of 69 isolates demonstrated that 7 (10%) and 9 (13%) were resistant to erythromycin and clindamycin, respectively. All isolates remain susceptible to penicillin.ConclusionInvasive GBS is an emerging disease in non-pregnant adults particularly in elderly and diabetes mellitus patients. Two-thirds of iGBS patients have concomittant bacteremia. Even though the overall mortality was 12% but a significant morbidity was observed.Disclosures All authors: No reported disclosures.