title: Expression analysis of adherence-associated genes in pneumococcal clinical isolates during adherence to human respiratory epithelial cells (in vitro) by real-time PCR.
abstract: Pneumococcal virulence determinants have been extensively studied but molecular evidence on virulence gene expression pattern is still lacking. We undertook this study to analyze the regulation pattern of adherence-associated genes; psaA, pspC, cbpG, including ply of serotypes 1, 7F, 19F and 23F clinical isolates during the bacterial adherence to human lung epithelial cells (in vitro), by real-time PCR. We were able to harvest the bacterial RNA (0.5-1 microg microL(-1)) from the infected host cell and analysis showed a consistent upregulation of psaA. Differential expressions were observed for pspC, cbpG and ply genes but the former was mostly upregulated whereas the later two frequently showed either no significant change or a downregulation. Partial nucleotide sequences of psaA, cbpG and ply were highly homologous among the isolates as well as against GenBank sequences (99%) whereas those for pspC were similar (98%) to allelic variants pspC-3 and pspC-5.
authors.forename: Mohd Nasir Mohd
authors.initials: MN
authors.lastname: Desa
authors.forename: Parasakthi
authors.initials: P
authors.lastname: Navaratnam
authors.forename: Jamunarani
authors.initials: J
authors.lastname: Vadivelu
authors.forename: Shamala Devi
authors.initials: SD
authors.lastname: Sekaran
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics* / Q000378:metabolism; D001422:Bacterial Adhesion; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D011008:Pneumococcal Infections / Q000382:microbiology*; D011018:Pneumonia, Pneumococcal / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology
chemical_list: D018829:Adhesins, Bacterial