Low but Increasing Prevalence of Reduced Beta-lactam Susceptibility Among Invasive Group B Streptococcal Isolates, US Population-Based Surveillance, 1998–2018. (21st December 2020)

• Record Type: Journal Article
• Authors: Kobayashi, Miwako; McGee, Lesley; Chochua, Sopio; Apostol, Mirasol; Alden, Nisha B; Farley, Monica M; Harrison, Lee H; Lynfield, Ruth; Vagnone, Paula Snippes; Smelser, Chad; Muse, Alison; Thomas, Ann R; Deng, Li; Metcalf, Benjamin J; Beall, Bernard W; Schrag, Stephanie J
• Is Part Of: Open forum infectious diseases. Volume 8:Number 2(2021)
• Publication Date: 2020-12-21
• Subjects: group B Streptococcus -- penicillin binding protein 2x -- reduced beta-lactam susceptibility -- whole-genome sequencing; Communicable diseases -- Periodicals; Medical microbiology -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.1093/ofid/ofaa634
• Languages: English
• ISSNs: 2328-8957

Abstract

Abstract: Background: Invasive group B Streptococcus (iGBS) isolates with mutations in the pbp2x gene that encodes penicillin binding protein 2x can have reduced beta-lactam susceptibility (RBLS) when susceptible by Clinical and Laboratory Standards Institute (CLSI) criteria. We assessed the emergence and characteristics of RBLS strains in US iGBS isolates. Methods: We analyzed iGBS isolates from 8 multistate population-based surveillance sites from 1998 to 2018. During 1998–2014, phenotypic antimicrobial susceptibility was determined by broth microdilution; criteria for 6 antibiotics were used to identify RBLS, followed by whole-genome sequencing (WGS). WGS for all isolates was added in 2015; we used phenotypic and genotypic results of >2000 isolates to validate phenotypic RBLS criteria and genotypic predictions. Since 2016, WGS has been used to screen for RBLS with broth microdilution confirmation of predicted RBLS isolates. Results: Of 28 269 iGBS isolates, 28 (0.1%) were nonsusceptible by CLSI criteria; 137 (0.5%) met RBLS criteria. RBLS isolates were detected in all Active Bacterial Core surveillance sites. The RBLS proportion increased, especially since 2013 (odds ratio, 1.17; 95% CI, 1.03–1.32); the proportion that were nonsusceptible remained stable. Conclusions: The RBSL proportion was low but increasing among US iGBS isolates. Ongoing monitoring is needed to detect emerging threats to prevention and treatment of GBS infections.