title: Rapid detection of meticillin-resistant Staphylococcus aureus bacteraemia using combined three-hour short-incubation matrix-assisted laser desorption/ionization time-of-flight MS identification and Alere Culture Colony PBP2a detection test.
abstract: Meticillin-resistant Staphylococcus aureus (MRSA) bloodstream infection is responsible for significant morbidity, with mortality rates as high as 60 % if not treated appropriately. We describe a rapid method to detect MRSA in blood cultures using a combined three-hour short-incubation BRUKER matrix-assisted laser desorption/ionization time-of-flight MS BioTyper protocol and a qualitative immunochromatographic assay, the Alere Culture Colony Test PBP2a detection test. We compared this combined method with a molecular method detecting the nuc and mecA genes currently performed in our laboratory. One hundred and seventeen S. aureus blood cultures were tested of which 35 were MRSA and 82 were meticillin-sensitive S. aureus (MSSA). The rapid combined test correctly identified 100 % (82/82) of the MSSA and 85.7 % (30/35) of the MRSA after 3 h. There were five false negative results where the isolates were correctly identified as S. aureus, but PBP2a was not detected by the Culture Colony Test. The combined method has a sensitivity of 87.5 %, specificity of 100 %, a positive predictive value of 100 % and a negative predictive value of 94.3 % with the prevalence of MRSA in our S. aureus blood cultures. The combined rapid method offers a significant benefit to early detection of MRSA in positive blood cultures.
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.|Division of Microbiology, Pathology and Laboratory Medicine, London Health Sciences, London, Ontario, Canada.|Schulich School of Medicine, Western University, London, Ontario, Canada.
authors.forename: Johannes Andries
authors.initials: JA
authors.lastname: Delport
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: Ivor
authors.initials: I
authors.lastname: Mohorovic
authors.affiliation: Division of Microbiology, Pathology and Laboratory Medicine, London Health Sciences, London, Ontario, Canada.
authors.forename: Sandi
authors.initials: S
authors.lastname: Burn
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.
authors.forename: John Kenneth
authors.initials: JK
authors.lastname: McCormick
authors.affiliation: Division of Microbiology, Pathology and Laboratory Medicine, London Health Sciences, London, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Schaus
authors.affiliation: Division of Microbiology, Pathology and Laboratory Medicine, London Health Sciences, London, Ontario, Canada.|Schulich School of Medicine, Western University, London, Ontario, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Lannigan
authors.affiliation: Division of Microbiology, Pathology and Laboratory Medicine, London Health Sciences, London, Ontario, Canada.|Schulich School of Medicine, Western University, London, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: John
mesh_terms: D016470:Bacteremia / Q000175:diagnosis* / Q000382:microbiology; D001426:Bacterial Proteins / Q000032:analysis*; D002846:Chromatography, Affinity / Q000379:methods*; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D046915:Penicillin-Binding Proteins / Q000032:analysis*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus