RESUMO
In this study, the whole genome sequences of two Streptococcus pneumoniae clinical isolates from South Korea were determined and compared. They were found to be the same serotype (11 A) and multilocus sequence typing analysis showed that they are single-locus variants (SLVs; ST8279 and ST166) of each other, differing at one allele (aroE). However, the ST8279 strain is extensively drug-resistant (XDR) whereas the ST166 strain is not. The genome of the XDR strain is very similar in structure to that of two previously reported genomes, AP200 (11 A:ST62) and 70585 (5:ST5803); however, some regions were inverted and there were some exogenous regions in the ST8279 strain. It was found that 6,502 single nucleotide polymorphisms are dispersed across the genome between the two serotype 11 A ST8279 and ST166 strains. Many of them are located in genes associated with antibiotic resistance. In addition, many amino acid differences were also identified in genes involved in DNA repair (mutL, uvrA and uvrC) and recombination (recU, recR and recA). On the basis of these results, it was inferred that the XDR strain did not evolve from its SLV via a single recombination event involving a large portion of the genome including the aroE gene. Rather, the strain likely evolved through many point mutations and recombination events involving small portions of the genome.
Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Infecções Pneumocócicas/microbiologia , Sorogrupo , Streptococcus pneumoniae/genética , DNA Bacteriano/genética , Genes Bacterianos/genética , Genoma Bacteriano , Técnicas de Genotipagem , Humanos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Polimorfismo de Nucleotídeo Único , República da Coreia , Alinhamento de Sequência , Sorotipagem , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/isolamento & purificação , Sequenciamento Completo do GenomaRESUMO
Recently, we have identified an extensively drug-resistant (XDR) Streptococcus pneumoniae serotype 15A isolate from a patient with bacterial meningitis. It belonged to sequence type 8279 (ST8279), a clone identified as XDR serotype 11A isolated in South Korea. We obtained and compared the genome sequences of an XDR 15A and an XDR 11A isolate. The genomes of two XDR isolates were highly identical, except for the capsular polysaccharide (cps) locus and another small region. Capsular switching from 11A to 15A may have occurred via recombination of the cps locus. The emergence of a new XDR clone via capsular switching would be a great concern for public health and in clinical settings.
Assuntos
Artrite Infecciosa/microbiologia , Cápsulas Bacterianas/genética , Doenças Transmissíveis Emergentes/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Meningite Pneumocócica/microbiologia , Ombro/microbiologia , Streptococcus pneumoniae/genética , Idoso , Artrite Infecciosa/sangue , Feminino , Genoma Bacteriano/genética , Humanos , Meningite Pneumocócica/sangue , Recombinação Genética , República da Coreia , Sorogrupo , Espondilite/sangue , Espondilite/microbiologia , Streptococcus pneumoniae/isolamento & purificação , Sequenciamento Completo do GenomaRESUMO
Of 608 Streptococcus pneumoniae clinical strains isolated at a hospital in South Korea during 2009-2014, sixteen (2.6%) were identified as levofloxacin resistant. The predominant serotype was 11A (9 isolates). Two novel sequence types of multidrug-resistant S. pneumoniae with serotype 11A were identified, indicating continuous diversification of resistant strains.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Levofloxacino/farmacologia , Infecções Pneumocócicas/epidemiologia , Infecções Pneumocócicas/microbiologia , Sorogrupo , Streptococcus pneumoniae/classificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , República da Coreia/epidemiologia , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genéticaRESUMO
BACKGROUND: The divergent epidemiological behavior of Streptococcus pneumoniae serotypes suggests that serotype-specific features such as capsule O-acetylation influence the propensity of a strain to cause invasive pneumococcal disease (IPD). We hypothesize that innate host factors mediate the observed negative association between IPD and the serotype 11A (ST11A) capsule O-acetyltransferase gene, wcjE. METHODS: We evaluated the ability of ficolin-2, an initiator of the lectin complement pathway that was previously shown to bind ST11A pneumococci, to recognize and mediate complement-dependent opsonophagocytosis of different pneumococcal serotypes. We supplemented findings with an epidemiological meta-analysis comparing invasiveness of the 30 most prevalent pneumococcal serotypes. RESULTS: Ficolin-2 bound ST11A capsule polysaccharide and other wcjE-containing pneumococcal serotypes, except ST9V and ST20B. Ficolin-2 did not bind wcjE-null serotypes, including the wcjE-null variant of ST11A, ST11E. We observed C1q-independent complement deposition and phagocytic killing of pneumococci expressing ST11A but not those expressing ST11E. Inhibition of ficolin-2 binding abrogated ST11A-associated complement deposition and phagocytosis. In children, invasiveness of ST11A was the lowest among serotypes tested in our meta-analysis, while ST9V was among the highest. CONCLUSIONS: Ficolin-2 mediates serum protection by recognizing specific O-acetylated epitopes of pneumococcal capsule polysaccharides, exemplifying a novel host-microbe interaction that innately offers serotype-specific immunity to IPD.