title: Real-time multiplex PCR for direct detection of methicillin-resistant Staphylococcus aureus (MRSA) in clinical samples enriched by broth culture.
abstract: A real-time multiplex PCR using the orfX and staphylococcal cassette chromosome (SCC) mec of Staphylococcus aureus was developed. The aim was to achieve a rapid and sensitive high-throughput method for direct detection of heterogeneous methicillin-resistant S. aureus (MRSA) in clinical samples, present in a low-endemic population, such as in Sweden. Consecutive broth enriched pooled clinical screening samples (nares, throat and/or perineum/groin) (n = 541 pools), broth enriched clinical samples showing growth of methicillin-sensitive S. aureus (MSSA) (n = 95 pools), clinical MRSA isolates (n = 173), MRSA reference strains (n = 43) and various coagulase-negative staphylococcal isolates (n = 33) were analyzed. The multiplex PCR detected all heterogeneous MRSA strains (n = 173) obtained in our area as well as all pooled consecutive broth enriched clinical samples with MRSA, i. e. 36 of 541 pools. None of the CoNS were positive. However, 18 out of 541 pools (3.3%) were positive in the multiplex PCR but no growth of MRSA could be detected by subculture and were regarded as false positive. Furthermore, the assay is rapid and reliable negative results can be delivered to the clinician within 18 h that will facilitate the infection control management of patients and hospital staff.
authors.affiliation: Departments of Laboratory Medicine, Clinical Microbiology, Örebro University Hospital, Sweden. bo.soderquist@orebroll.se
authors.forename: Bo
authors.initials: B
authors.lastname: Söderquist
authors.forename: Marita
authors.initials: M
authors.lastname: Neander
authors.forename: Olaf
authors.initials: O
authors.lastname: Dienus
authors.forename: Johanna
authors.initials: J
authors.lastname: Zimmermann
authors.forename: Carolina
authors.initials: C
authors.lastname: Berglund
authors.forename: Andreas
authors.initials: A
authors.lastname: Matussek
authors.forename: Paula
authors.initials: P
authors.lastname: Mölling
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*; D046915:Penicillin-Binding Proteins; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013548:Sweden / Q000453:epidemiology; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; C414317:SarH1 protein, Staphylococcus aureus; D014157:Transcription Factors; C487789:mecA protein, Staphylococcus aureus