title: Evaluation of approaches to monitor Staphylococcus aureus virulence factor expression during human disease.
abstract: Staphylococcus aureus is a versatile pathogen of medical significance, using multiple virulence factors to cause disease. A prophylactic S. aureus 4-antigen (SA4Ag) vaccine comprising capsular polysaccharide (types 5 and 8) conjugates, clumping factor A (ClfA) and manganese transporter C (MntC) is under development. This study was designed to characterize S. aureus isolates recovered from infected patients and also to investigate approaches for examining expression of S. aureus vaccine candidates and the host response during human infection. Confirmation of antigen expression in different disease states is important to support the inclusion of these antigens in a prophylactic vaccine. Hospitalized patients with diagnosed S. aureus wound (27) or bloodstream (24) infections were enrolled. Invasive and nasal carriage S. aureus isolates were recovered and characterized for genotypic diversity. S. aureus antigen expression was evaluated directly by real-time, quantitative, reverse-transcriptase PCR (qRT-PCR) analysis and indirectly by serology using a competitive Luminex immunoassay. Study isolates were genotypically diverse and all had the genes encoding the antigens present in the SA4Ag vaccine. S. aureus nasal carriage was detected in 55% of patients, and in those subjects 64% of the carriage isolates matched the invasive strain. In swab samples with detectable S. aureus triosephosphate isomerase housekeeping gene expression, RNA transcripts encoding the S. aureus virulence factors ClfA, MntC, and capsule polysaccharide were detected by qRT-PCR. Antigen expression was indirectly confirmed by increases in antibody titer during the course of infection from acute to convalescent phase. Demonstration of bacterial transcript expression together with immunological response to the SA4Ag antigens in a clinically relevant patient population provides support for inclusion of these antigens in a prophylactic vaccine.
authors.affiliation: VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Wouter
authors.initials: W
authors.lastname: Rozemeijer
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Pamela
authors.initials: P
authors.lastname: Fink
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rojas
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: C Hal
authors.initials: CH
authors.lastname: Jones
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Danka
authors.initials: D
authors.lastname: Pavliakova
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Peter
authors.initials: P
authors.lastname: Giardina
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Ellen
authors.initials: E
authors.lastname: Murphy
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Paul
authors.initials: P
authors.lastname: Liberator
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Qin
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Douglas
authors.initials: D
authors.lastname: Girgenti
authors.affiliation: VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Remco P H
authors.initials: RP
authors.lastname: Peters
authors.affiliation: VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Paul H M
authors.initials: PH
authors.lastname: Savelkoul
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Kathrin U
authors.initials: KU
authors.lastname: Jansen
authors.affiliation: Pfizer Vaccine Research and Development, Pearl River, New York, United States of America.
authors.forename: Annaliesa S
authors.initials: AS
authors.lastname: Anderson
authors.affiliation: VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Kluytmans
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016667:Bacterial Capsules / Q000276:immunology; D003030:Coagulase / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000382:microbiology; D065288:Serogroup; D013203:Staphylococcal Infections / Q000382:microbiology*; D013209:Staphylococcal Vaccines / Q000276:immunology; D013211:Staphylococcus aureus / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
chemical_list: C515944:ClfA protein, Staphylococcus aureus; D003030:Coagulase; D013209:Staphylococcal Vaccines; D037521:Virulence Factors