title: Real-time polymerase chain reaction and culture in the diagnosis of invasive group B streptococcal disease in infants: a retrospective study.
abstract: Group B streptococcus (GBS) is a leading cause of invasive disease in infants. Accurate and rapid diagnosis is crucial to reduce morbidity and mortality. Real-time polymerase chain reaction (PCR) targeting the dltR gene was utilised for the direct detection of GBS DNA in blood and cerebrospinal fluid (CSF) from infants at an Irish maternity hospital. A retrospective review of laboratory and patient records during the period 2011-2013 was performed in order to evaluate PCR and culture for the diagnosis of invasive GBS disease. A total of 3570 blood and 189 CSF samples from 3510 infants had corresponding culture and PCR results. Culture and PCR exhibited concordance in 3526 GBS-negative samples and 13 (25%) GBS-positive samples (n = 53). Six (11%) and 34 (64%) GBS-positive samples were positive only in culture or PCR, respectively. Culture and PCR identified more GBS-positive infants (n = 47) than PCR (n = 43) or culture (n = 16) alone. Using culture as the reference standard, the sensitivity, specificity, and positive and negative predictive values for PCR on blood samples were 71.4%, 99.2%, 25% and 99.9%, and for CSF samples, they were 60%, 97.8%, 42.9% and 98.9%, respectively. The sensitivity and positive predictive values were improved (blood: 84.6% and 55%; CSF: 77.8% and 100%, respectively) when maternal risk factors and other laboratory test results were considered. The findings in this study recommend the use of direct GBS real-time PCR for the diagnosis of GBS infection in infants with a clinical suspicion of invasive disease and as a complement to culture, but should be interpreted in the light of other laboratory and clinical findings.
authors.affiliation: Epidemiology and Molecular Biology Unit, Temple Street Children's University Hospital, Temple Street, Dublin, Ireland. meehanmary@yahoo.co.uk.
authors.forename: M
authors.initials: M
authors.lastname: Meehan
authors.affiliation: Department of Clinical Microbiology, Rotunda Hospital, Dublin, Ireland.|Royal College of Surgeons in Ireland, Dublin, Ireland.
authors.forename: M
authors.initials: M
authors.lastname: Cafferkey
authors.affiliation: Department of Clinical Microbiology, Rotunda Hospital, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Corcoran
authors.affiliation: Temple Street Children's University Hospital, Temple Street, Dublin, Ireland.|Rotunda Hospital, Dublin, Ireland.|Royal College of Surgeons in Ireland, Dublin, Ireland.
authors.forename: A
authors.initials: A
authors.lastname: Foran
authors.affiliation: Rotunda Hospital, Dublin, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: Hapnes
authors.affiliation: Department of Clinical Microbiology, Rotunda Hospital, Dublin, Ireland.
authors.forename: D
authors.initials: D
authors.lastname: LeBlanc
authors.affiliation: Irish Meningococcal and Meningitis Reference Laboratory, Temple Street Children's University Hospital, Temple Street, Dublin, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: McGuinness
authors.affiliation: Department of Clinical Microbiology, Rotunda Hospital, Dublin, Ireland.
authors.forename: U
authors.initials: U
authors.lastname: Nusgen
authors.affiliation: Irish Meningococcal and Meningitis Reference Laboratory, Temple Street Children's University Hospital, Temple Street, Dublin, Ireland.
authors.forename: N
authors.initials: N
authors.lastname: O'Sullivan
authors.affiliation: Epidemiology and Molecular Biology Unit, Temple Street Children's University Hospital, Temple Street, Dublin, Ireland.|Irish Meningococcal and Meningitis Reference Laboratory, Temple Street Children's University Hospital, Temple Street, Dublin, Ireland.|Health Protection Surveillance Centre, Dublin, Ireland.
authors.forename: R
authors.initials: R
authors.lastname: Cunney
authors.affiliation: Irish Meningococcal and Meningitis Reference Laboratory, Temple Street Children's University Hospital, Temple Street, Dublin, Ireland.|Department of Clinical Microbiology, Rotunda Hospital, Dublin, Ireland.|Royal College of Surgeons in Ireland, Dublin, Ireland.
authors.forename: R
authors.initials: R
authors.lastname: Drew
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D001769:Blood / Q000382:microbiology; D002555:Cerebrospinal Fluid / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011237:Predictive Value of Tests; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis*; D013292:Streptococcus agalactiae / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*