RESUMO
Twentythree clinical Streptococcus pneumoniae (SP) strains were isolated from blood and sputum specimens from the Second Affiliated Hospital of Wenzhou Medical College in 2009. These strains and the ATCC 49619 standard strain were cultured and suspended in normal saline (at a turbidity of 1.0 McFarland). The production of interleukin (IL)8, intracellular adhesion molecule1 (ICAM1) and IL10 in THP1 cells following stimulation with the SP suspension was analyzed by an enzyme-linked immunosorbent assay. The concentrations of IL8, ICAM1 and IL10 from the THP1 monocytes were greater than those of the blank control following stimulation with the SP suspension. No significant difference was identified in the levels of IL8, ICAM1 and IL10 secretion between THP1 monocytes stimulated by bloodborne SP (bbSP) and sputumborne SP (sbSP).
Assuntos
Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-10/metabolismo , Interleucina-8/metabolismo , Monócitos/metabolismo , Pneumonia Pneumocócica/microbiologia , Escarro/metabolismo , Streptococcus pneumoniae/isolamento & purificação , Aminoaciltransferases/genética , Células Cultivadas , DNA Bacteriano/genética , Ensaio de Imunoadsorção Enzimática , Humanos , Monócitos/microbiologia , Proteínas de Ligação às Penicilinas/genética , Pneumonia Pneumocócica/sangue , Pneumonia Pneumocócica/genética , Reação em Cadeia da Polimerase em Tempo Real , Escarro/microbiologia , Streptococcus pneumoniae/genéticaRESUMO
BACKGROUND: Streptococcus pneumoniae (SP) is the major cause of childhood mortality worldwide, we need to understand virulence genes of SP so can better target the treatment.We investigated the expression of virulence genes PsaA and CpsA in different strains of SP interacting with monocyte cell line (THP-1) or pneumocyte cell line (A549) and the possible mechanism of SP invasion of the blood system. METHODS: A total of 23 strains of SP were collected from hospitalized patients (blood-derived and sputum-derived) in the Second Affiliated Hospital of Wenzhou Medical College. The strains and ATCC 49619 were cultured, and RNAs were extracted. THP-1 and A549 cells were stimulated by different SP and ATCC 49619 for 4 h and 8 h, respectively. Quantitative real-time PCR was used to analyze the mRNA expression of PsaA and CpsA. The data were analyzed by SPSS 17.0. RESULTS: The mRNA level of PsaA and CpsA were all significantly increased in clinical SP strains when compared to ATCC49619 after tedTHP-1 and A549 cells were stimulated. Clinical SPs showed higher virulence compared with ATCC49619. CONCLUSIONS: The expression of CpsA is the basis of the pathogenicity of SP. The expression of virulence gene PsaA may be helpful to the invasion of SP to the blood system.