Genomic analysis of nontypeable pneumococci causing invasive pneumococcal disease in South Africa, 2003–2013
Autor: | Thabo Mohale, Penny Crowther-Gibson, Mushal Allam, Kedibone M. Ndlangisa, Anne von Gottberg, Mignon du Plessis, Nicole Wolter |
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Jazyk: | angličtina |
Rok vydání: | 2016 |
Předmět: |
0301 basic medicine
Serotype Nontypeable Genotype 030106 microbiology Erythromycin Biology medicine.disease_cause History 21st Century Pneumococcal conjugate vaccine Pneumococcal Infections Microbiology 03 medical and health sciences South Africa Antibiotic resistance Bacterial Proteins Streptococcus pneumoniae Drug Resistance Bacterial Genetics medicine Humans Serotyping Phylogeny High-Throughput Nucleotide Sequencing Invasive pneumococcal disease Genomics medicine.disease Virology Anti-Bacterial Agents Pneumococcal infections Whole genome sequencing Population Surveillance Multilocus sequence typing Genome Bacterial Biotechnology medicine.drug Research Article Multilocus Sequence Typing |
Zdroj: | BMC Genomics |
ISSN: | 1471-2164 |
Popis: | Background The capsular polysaccharide is the principal virulence factor of Streptococcus pneumoniae and a target for current pneumococcal vaccines. However, some pathogenic pneumococci are serologically nontypeable [nontypeable pneumococci (NTPn)]. Due to their relative rarity, NTPn are poorly characterized, and, as such, limited data exist which describe these organisms. We aimed to describe disease and genotypically characterize NTPn causing invasive pneumococcal disease in South Africa. Results Isolates were detected through national, laboratory-based surveillance for invasive pneumococcal disease in South Africa and characterized by whole genome analysis. We predicted ancestral serotypes (serotypes from which NTPn may have originated) for Group I NTPn using multilocus sequence typing and capsular region sequence analyses. Antimicrobial resistance patterns and mutations potentially causing nontypeability were identified. From 2003–2013, 39 (0.1 %, 39/32,824) NTPn were reported. Twenty-two (56 %) had partial capsular genes (Group I) and 17 (44 %) had complete capsular deletion of which 15 had replacement by other genes (Group II). Seventy-nine percent (31/39) of our NTPn isolates were derived from encapsulated S. pneumoniae. Ancestral serotypes 1 (27 %, 6/22) and 8 (14 %, 3/22) were most prevalent, and 59 % (13/22) of ancestral serotypes were serotypes included in the 13-valent pneumococcal conjugate vaccine. We identified a variety of mutations within the capsular region of Group I NTPn, some of which may be responsible for the nontypeable phenotype. Nonsusceptibility to tetracycline and erythromycin was higher in NTPn than encapsulated S. pneumoniae. Conclusions NTPn are currently a rare cause of invasive pneumococcal disease in South Africa and represent a genetically diverse collection of isolates. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2808-x) contains supplementary material, which is available to authorized users. |
Databáze: | OpenAIRE |
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