title: Transcriptome analysis of Burkholderia pseudomallei T6SS identifies Hcp1 as a potential serodiagnostic marker.
abstract: Burkholderia pseudomallei, the causative agent of melioidosis, is able to survive extreme environments and utilizes various virulence factors for survival and pathogenicity. To compete and survive within these different ecological niches, B. pseudomallei has evolved specialized pathways, including the Type VI secretion systems (T6SSs), that have a role in pathogenesis as well as interbacterial interactions. We examined the expression profile of B. pseudomallei T6SS six gene clusters during infection of U937 macrophage cells. T6SS-5 was robustly transcribed while the other five clusters were not significantly regulated proposing the utility of T6SS-5 as a potential biomarker of exposure to B. pseudomallei. Transcription of T6SS regulators VirAG and BprB was also not significant during infection when compared to bacteria grown in culture. Guided by these findings, three highly expressed T6SS genes, tssJ-4, hcp1 and tssE-5, were expressed as recombinant proteins and screened against melioidosis patient sera by western analysis and ELISA. Only Hcp1 was reactive by both types of analysis. The recombinant Hcp1 protein was further evaluated against a cohort of melioidosis patients (n = 32) and non-melioidosis individuals (n = 20) sera and the data clearly indicates a higher sensitivity (93.7%) and specificity (100%) for Hcp1 compared to bacterial lysate. The detection of anti-Hcp1 antibodies in patients' sera indicating the presence of B. pseudomallei highlights the potential of Hcp1 to be further developed as a serodiagnostic marker for melioidosis.
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Chieng
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia.
authors.forename: Rahmah
authors.initials: R
authors.lastname: Mohamed
authors.affiliation: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, Bangi, Selangor, Malaysia. Electronic address: sheila@ukm.edu.my.
authors.forename: Sheila
authors.initials: S
authors.lastname: Nathan
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D058947:Bacterial Secretion Systems; D015415:Biomarkers / Q000032:analysis*; D016957:Burkholderia pseudomallei / Q000235:genetics* / Q000254:growth & development; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D020869:Gene Expression Profiling; D006801:Humans; D008264:Macrophages / Q000382:microbiology; D008554:Melioidosis / Q000175:diagnosis*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods; D037521:Virulence Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D015415:Biomarkers; D011994:Recombinant Proteins; D037521:Virulence Factors
keywords: Burkholderia pseudomallei; Hcp1; Melioidosis; T6SS