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. 2016 Sep 22;16(1):221.
doi: 10.1186/s12866-016-0836-y.

Development and performance evaluation of a recombinase polymerase amplification assay for the rapid detection of group B streptococcus

Christina Clarke  1 , Louise O'Connor  2 , Heather Carré-Skinner  3 , Olaf Piepenburg  3 , Terry J Smith  1
Affiliations

Development and performance evaluation of a recombinase polymerase amplification assay for the rapid detection of group B streptococcus

Christina Clarke et al. BMC Microbiol. .

Abstract

Background: Despite the implementation of prevention guidelines, group B Streptococcal (GBS) infection remains a leading cause of sepsis, pneumonia, and meningitis, resulting in significant neonatal morbidity and mortality. Preventive approaches that identify women at risk of transmitting GBS have reduced the incidence of neonatal GBS disease, and dramatically decreased the associated mortality rates. However, there is an on-going requirement for a near-patient diagnostic test for GBS that can be carried out at the time of delivery, ideally in the labour ward setting, particularly for women of unknown GBS colonisation status at the time of delivery.

Methods: In this study, a Recombinase Polymerase Amplification (RPA) assay was developed and performance evaluated for the detection of group B Streptococcus in vaginal swabs. The assay uses the cAMP factor (cfb) gene of GBS as the target gene. The analytical performance of the assay was evaluated by testing a panel of GBS reference strains and clinical isolates, and non-GBS organisms. The limit of detection was determined and the clinical performance was evaluated by testing 124 vaginal swabs from women with both GBS positive and negative status.

Results: Based on specificity testing carried out the assay was shown to be specific for the target of interest. The limit of detection of the assay was shown to be between six and 12 genome copies and was comparable to that of a real-time PCR assay, both achieving a limit of detection below 12.5 genome copies. The performance of both assays when applied to clinical samples was identical.

Conclusion: A specific, sensitive RPA assay for GBS was developed. The performance of the assay for testing of clinical samples is within the acceptable range.

Keywords: GBS; Group B Streptococcus; Labour; Limit of detection; Near-patient tests; Neonatal infection; Neonates; Point-of-care; Recombinase Polymerase Amplification; Specificity.

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Figures

Fig. 1
Fig. 1
RPA Amplification curves obtained from a panel of GBS isolates tested with the RPA GBS assay. All isolates, listed in Table 1, were tested in triplicate. a shows amplification curves obtained for isolates BCCM 15081, 15082, and BCCM15083. b shows amplification curves obtained for isolates BCCM 15083, 15084, and BCCM15085 (tested in duplicate)
Fig. 2
Fig. 2
RPA results obtained when a Streptococcus Genus exclusivity panel, listed in Table 2, was tested in the RPA GBS assay. a, b and c show amplification curves for only for the positive control GBS 15081, demonstrating specificity of the assay for GBS
Fig. 3
Fig. 3
Representative RPA amplification curves obtained for eight of the 124 clinical samples tested in the RPA GBS assay
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References

    1. Verani JR, Mcgee L, Schrag SJ. Prevention of Perinatal Group B Streptococcal Disease. Atlanta: Centers for Disease Control and Prevention; 2010. - PubMed
    1. Oh W. Early onset neonatal group B streptococcal sepsis. Am J Perinatol. 2013;30(2):143–7. doi: 10.1055/s-0032-1332804. - DOI - PubMed
    1. Hughes RG, Brocklehurst P, Heath P, Stenson B. Prevention of Early-onset Neonatal Group B Streptococcal Disease. 2. London: Royal College of Obstetricians and Gynaecologists (RCOG); 2012.
    1. Schuchat A. Group B streptococcus. Lancet. 1999;353(9146):51–6. doi: 10.1016/S0140-6736(98)07128-1. - DOI - PubMed
    1. Schrag SJ, Zywicki S, Farley MM, Reingold AL, Harrison LH, Lefkowitz LB, Hadler JL, Danila R, Cieslak PR, Schuchat A. Group B streptococcal disease in the era of intrapartum antibiotic prophylaxis. N Engl J Med. 2000;342:15–20. doi: 10.1056/NEJM200001063420103. - DOI - PubMed

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