Clonal lineages and antimicrobial resistance of nonencapsulated Streptococcus pneumoniae in the post-pneumococcal conjugate vaccine era in Japan. (April 2021)

• Record Type: Journal Article
• Authors: Kawaguchiya, Mitsuyo; Urushibara, Noriko; Aung, Meiji Soe; Kudo, Kenji; Ito, Masahiko; Sumi, Ayako; Kobayashi, Nobumichi
• Is Part Of: International journal of infectious diseases. Volume 105(2021)
• Page Start: 695
• Page End: 701
• Publication Date: 2021-04
• Subjects: Nonencapsulated -- Streptococcus pneumoniae -- Antimicrobial susceptibility -- Multi-drug resistance -- Sequence type -- Pneumococcal surface protein K; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2021.02.109
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: The prevalence rate of Nonencapsulated Streptococcus pneumoniae (NESp) was 1.6% across all study periods. NESp isolates assigned to null capsule clade 1 ( pspK +), 94.4% or 2 ( aliC+ / aliD+ ), 5.6%. Dominant sequences related to sporadic ST1106 lineage or PMEN clone Denmark 14 -ST230. Multidrug resistance in 88.7% of NESp isolates (all ST7502, ST4845, ST11379 lineages). Abstract: Objectives: The emergence and spread of nonencapsulated Streptococcus pneumoniae (NESp) is a public health concern in the post-pneumococcal conjugate vaccine era. We analyzed the prevalence, molecular characteristics, and antimicrobial resistance of NESp responsible for noninvasive infections in northern Japan. Methods: NESp isolates were identified using molecular and phenotypical methods among 4463 S. pneumoniae isolates from noninvasive infection cases during 4 study periods between January 2011 and January 2019. NESp isolates were analyzed for antimicrobial susceptibility, genotype, and virulence-associated genes. Results: Seventy-one NESp isolates were identified (1.6% of total clinical isolates) and assigned to the null capsule clade (NCC)1 ( pspK +) (94.4%) or NCC2 ( aliC +/ aliD +) (5.6%). The dominant sequence types (STs) were ST7502 (23.9%), ST4845 (19.7%), ST16214 (11.3%), ST11379 (9.9%), and ST7786 (7.0%). These 5 dominant STs and all 7 novel STs were related to the sporadic NESp lineage ST1106 or PMEN clone Denmark 14 -ST230. High non-susceptibility rates of NESp were observed for trimethoprim-sulfamethoxazole, erythromycin, and tetracycline (>92.9%), and multidrug resistance was observed in 88.7% of the NESp isolates, including all ST7502, ST4845, and ST11379 isolates. Conclusions: The study revealed that the dominant clonal groups of NESp were associated with a high prevalence of non-susceptibility to antimicrobials in northern Japan.