L Setchanova1, A Alexandrova2, D Pencheva3, I Sirakov2, K Mihova3, R Kaneva3, I Mitov2. 1. Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia, 2 Zdrave Str., 1431 Sofia, Bulgaria. Electronic address: lsetchanova@medfac.mu-sofia.bg. 2. Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia, 2 Zdrave Str., 1431 Sofia, Bulgaria. 3. Department of Medical Chemistry and Biochemistry, Molecular Medicine Center, Medical University of Sofia, Sofia, Bulgaria.
Abstract
OBJECTIVES: Pneumococcal conjugate vaccines (PCVs) have reduced the incidence of pneumococcal disease, but non-vaccine serotypes are of concern, particularly if antimicrobial-resistant. This study retrospectively evaluated the serotype-specific clonality of paediatric multidrug-resistant (MDR) invasive and non-invasive Streptococcus pneumoniae isolates collected following PCV10 introduction (2011-2017) in Bulgaria. METHODS: Capsular types, drug resistance patterns and multilocus sequence typing (MLST) of the most common MDR S. pneumoniae serotypes sampled from children were determined. RESULTS: Overall, the rate of MDR pneumococci was 44.6% (107/240). The most common serotypes among MDR strains were 19F (25.2%), 19A (19.6%), 6C (13.1%), 6A and 23A (6.5% each) and 15A (4.7%), contributing 75.7% of all MDR strains. With the exception of serotype 19F, the remaining serotypes were non-PCV10 types. Among MDR pneumococci, the most frequently found sequence types were ST320 (30.4%; 19A and 19F), ST386 (12.7%; 6C and 6A) and ST8029 (5.1%; 23A). The majority of MDR STs (74.7%) belonged to PMEN clonal complexes, of which the most common were CC320 (Taiwan19F-14), CC315 (Poland6B-20) and CC180 (Netherlands3-31), accounting for 43.0%, 13.9% and 5.1%, respectively. In the post-vaccine period, a shift in the genetic structure of serotype 19A was found, with a significant increase of PMEN-14 (CC320) and a concurrent decrease of the major clone Denmark14-32 (CC230) observed prior to PCV10 introduction in Bulgaria. CONCLUSIONS: Clonality was found behind the wide distribution of MDR capsular types 19A, 6C, 23A and 3 following vaccine introduction, and a highly multiresistant and virulent clone Taiwan19F-14/ST320 has emerged as a common pathogen in children.
OBJECTIVES:Pneumococcal conjugate vaccines (PCVs) have reduced the incidence of pneumococcal disease, but non-vaccine serotypes are of concern, particularly if antimicrobial-resistant. This study retrospectively evaluated the serotype-specific clonality of paediatric multidrug-resistant (MDR) invasive and non-invasive Streptococcus pneumoniae isolates collected following PCV10 introduction (2011-2017) in Bulgaria. METHODS: Capsular types, drug resistance patterns and multilocus sequence typing (MLST) of the most common MDR S. pneumoniae serotypes sampled from children were determined. RESULTS: Overall, the rate of MDR pneumococci was 44.6% (107/240). The most common serotypes among MDR strains were 19F (25.2%), 19A (19.6%), 6C (13.1%), 6A and 23A (6.5% each) and 15A (4.7%), contributing 75.7% of all MDR strains. With the exception of serotype 19F, the remaining serotypes were non-PCV10 types. Among MDR pneumococci, the most frequently found sequence types were ST320 (30.4%; 19A and 19F), ST386 (12.7%; 6C and 6A) and ST8029 (5.1%; 23A). The majority of MDR STs (74.7%) belonged to PMEN clonal complexes, of which the most common were CC320 (Taiwan19F-14), CC315 (Poland6B-20) and CC180 (Netherlands3-31), accounting for 43.0%, 13.9% and 5.1%, respectively. In the post-vaccine period, a shift in the genetic structure of serotype 19A was found, with a significant increase of PMEN-14 (CC320) and a concurrent decrease of the major clone Denmark14-32 (CC230) observed prior to PCV10 introduction in Bulgaria. CONCLUSIONS: Clonality was found behind the wide distribution of MDR capsular types 19A, 6C, 23A and 3 following vaccine introduction, and a highly multiresistant and virulent clone Taiwan19F-14/ST320 has emerged as a common pathogen in children.
Authors: Samanta C G Almeida; Stephanie W Lo; Paulina A Hawkins; Rebecca A Gladstone; Ana Paula Cassiolato; Keith P Klugman; Robert F Breiman; Stephen D Bentley; Lesley McGee; Maria-Cristina de C Brandileone Journal: Microb Genom Date: 2021-10