TY - JOUR
T1 - Molecular characterisation of group A streptococcus isolates recovered from the north-west of Pretoria, South Africa
AU - Khosa, X. V.
AU - Kgasha, O.
AU - Mabhuza, H.
AU - Moshe, M.
AU - Engel, K.
AU - Nchabeleng, M.
N1 - Funding Information:
Declaration. The research for this study was done in partial fulfilment of XVK’s MSc (Medical Microbiology) degree at Sefako Makgatho Health Sciences University. Acknowledgements. We thank the DGM laboratory management for granting us permission to collect GAS clinical isolates. We gratefully acknowledge Dr Mark E Engel, principal investigator of the AFROStrep Registry project based at the University of Cape Town, for collaboration and for the training provided for the molecular work. We also acknowledge the dedication of the research nurse. Lastly, we would like to acknowledge the late Prof. Bongani Mayosi, who was involved in the conceptualisation of this study. Author contributions. XVK, the MSc student, performed experiments, analysed data and drafted the manuscript. OK was involved in data analysis and interpretion as well drafting of the manuscript. HM and MM were involved in throat swab sample collection and patient recruitment. MN was involved in the design of the local study, modifying the UCT protocol, as well as the critical revision of the manuscript. KE and the RHD team at the University of Cape Town shared their study protocol as well as training in and assisting with the optimisation of the emm typing technique and data interpretation. Funding. The work reported was made possible through funding by the South African Medical Research Council (SAMRC) through its Division of Research Capacity Development under the internship scholarship programme (XVK). The content of this article is the sole responsibility of the authors and does not necessarily represent the official views of the SAMRC.
Publisher Copyright:
© 2021 South African Medical Association. All rights reserved.
PY - 2021/5
Y1 - 2021/5
N2 - Background. Group A streptococcus (GAS) is a human pathogen responsible for a wide range of invasive and non-invasive infections. Pharyngitis caused by GAS may have complications such as acute rheumatic fever subsequently leading to rheumatic heart disease (RHD). RHD continues to have high morbidity and mortality and affects millions of children and young adults, mostly in developing countries. An effective preventive vaccine against GAS may reduce the morbidity and mortality. A 30-valent M-protein-based vaccine is currently at the clinical trials stage of development. Potential vaccine coverage will depend on the geographical distribution of GAS emm (M protein) types. Objectives. To determine the emm types of GAS isolates circulating in the north-west of Pretoria, South Africa. Methods. Throat swabs were collected from patients aged 3 - 20 years presenting with pharyngitis at one local clinic. In addition, GAS clinical isolates were collected from the National Health Laboratory Service diagnostic laboratory. Emm genotyping was done on the GAS isolates by amplification of the emm gene followed by sequencing of the 5' portion of the gene. The emm types were correlated with the types in the vaccine. Results. A total of 54 GAS isolates were collected, comprising 19 pharyngitis and 35 clinical isolates. We found 15 different emm types among the 43 GAS isolates that were successfully sequenced. Eleven isolates (20%) could not be typed. The most prevalent emm type was 92 (26%), which is part of the 30-valent vaccine. This was followed by emm 25 and 75, each accounting for 12% of the isolates. Up to 67% of the emm types are not covered in the 30-valent vaccine. Conclusions. Fifteen emm types were identified, of which 92 was the most prevalent. It is concerning that 67% of the emm types are not covered in the vaccine currently under development. It is recommended that surveillance studies be extended to include other parts of the country in order to expand knowledge of the circulating emm types.
AB - Background. Group A streptococcus (GAS) is a human pathogen responsible for a wide range of invasive and non-invasive infections. Pharyngitis caused by GAS may have complications such as acute rheumatic fever subsequently leading to rheumatic heart disease (RHD). RHD continues to have high morbidity and mortality and affects millions of children and young adults, mostly in developing countries. An effective preventive vaccine against GAS may reduce the morbidity and mortality. A 30-valent M-protein-based vaccine is currently at the clinical trials stage of development. Potential vaccine coverage will depend on the geographical distribution of GAS emm (M protein) types. Objectives. To determine the emm types of GAS isolates circulating in the north-west of Pretoria, South Africa. Methods. Throat swabs were collected from patients aged 3 - 20 years presenting with pharyngitis at one local clinic. In addition, GAS clinical isolates were collected from the National Health Laboratory Service diagnostic laboratory. Emm genotyping was done on the GAS isolates by amplification of the emm gene followed by sequencing of the 5' portion of the gene. The emm types were correlated with the types in the vaccine. Results. A total of 54 GAS isolates were collected, comprising 19 pharyngitis and 35 clinical isolates. We found 15 different emm types among the 43 GAS isolates that were successfully sequenced. Eleven isolates (20%) could not be typed. The most prevalent emm type was 92 (26%), which is part of the 30-valent vaccine. This was followed by emm 25 and 75, each accounting for 12% of the isolates. Up to 67% of the emm types are not covered in the 30-valent vaccine. Conclusions. Fifteen emm types were identified, of which 92 was the most prevalent. It is concerning that 67% of the emm types are not covered in the vaccine currently under development. It is recommended that surveillance studies be extended to include other parts of the country in order to expand knowledge of the circulating emm types.
UR - http://www.scopus.com/inward/record.url?scp=85105318873&partnerID=8YFLogxK
U2 - 10.7196/SAMJ.2021.v111i5.14613
DO - 10.7196/SAMJ.2021.v111i5.14613
M3 - Article
C2 - 34852893
AN - SCOPUS:85105318873
SN - 0256-9574
VL - 111
SP - 487
EP - 490
JO - South African Medical Journal
JF - South African Medical Journal
IS - 5
ER -