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van der Linden M, Jaschek M, Junker J, Levina N, Weidenhaupt B. Evaluation of the 'HG Group B Streptococcus' loop-mediated isothermal amplification assay for accurate identification of Streptococcus agalactiae. J Med Microbiol 2022; 71. [PMID: 36748534 DOI: 10.1099/jmm.0.001609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
This study evaluated the HiberGene Group B Streptococcus test, a CE-IVD-approved molecular assay for rapid detection of Streptococcus agalactiae [Group B Streptococcus (GBS)] in human clinical specimens. Performance of the assay in terms of specificity, sensitivity and genotype inclusivity was investigated using an extended specificity panel of 113 human and animal GBS isolates, and eight isolates from other streptococcal species, from the isolate collection of the German National Reference Center for Streptococci. Broth cultures were tested according to the manufacturer's protocol, including lysis, heat denaturation and isothermal amplification. All 104/104 (100 %) human GBS isolates of nine serotypes (Ia, Ib, II, III, IV, V, VI, VII, VIII and non-typeable) were correctly identified by the assay as GBS. Additionally, 7/9 (78 %) GBS isolates from elephants were also correctly identified. Six isolates of other streptococcal species/subspecies (Streptococcus anginosus, S. constellatus, S. castoreus, S. dysgalactiae and S. dysgalactiae equisimilis) were correctly reported as negative. Two S. pyogenes (Group A Streptococcus) isolates gave invalid results. The HG Group B Streptococcus assay identified human GBS isolates in culture with 100 % sensitivity.
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Affiliation(s)
- Mark van der Linden
- German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Mareike Jaschek
- German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Julia Junker
- German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Natascha Levina
- German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Bruno Weidenhaupt
- German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, Pauwelsstrasse 30, D-52074 Aachen, Germany
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Albuquerque RC, Moreno ACR, Dos Santos SR, Ragazzi SLB, Martinez MB. Multiplex-PCR for diagnosis of bacterial meningitis. Braz J Microbiol 2019; 50:435-443. [PMID: 30796713 PMCID: PMC6863191 DOI: 10.1007/s42770-019-00055-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/17/2018] [Indexed: 10/27/2022] Open
Abstract
Considering the great lethality and sequels caused by meningitis, rapid diagnosis and prompt treatment initiation have a great impact on patient outcome. Here, we developed a multiplex-PCR for simultaneous detection of the four most prevalent bacterial pathogens directly in CSF samples. The multiplex-PCR was designed to detect the following genes: fbsA (Streptococcus agalactiae), lytA (Streptococcus pneumoniae), crtA (Neisseria meningitidis), p6 (Haemophilus influenzae), and 16S rRNA (any bacterial agent). The multiplex-PCR showed a DNA detection limit of 1 pg/μL. Among 447 CSF samples tested, 40 were multiplex-PCR positive, in which 27 and 13 had positive and negative bacterial culture, respectively. Our multiplex-PCR is fast, reliable, and easily implementable into a laboratory routine for bacterial meningitis confirmation, especially for patients who previously started antimicrobial therapy. Our molecular approach can substantially improve clinical diagnosis and epidemiological measures of meningitis disease burden.
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Affiliation(s)
- Renata Chaves Albuquerque
- Faculdade de Ciências Farmacêuticas, Department of Clinical Chemistry and Toxicology, Universidade de São Paulo (USP), São Paulo, Brazil
| | - Ana Carolina Ramos Moreno
- Faculdade de Ciências Farmacêuticas, Department of Clinical Chemistry and Toxicology, Universidade de São Paulo (USP), São Paulo, Brazil.
- Biomedical Sciences Institute, Vaccine Development Laboratory, Department of Microbiology, USP, São Paulo, Brazil.
| | | | | | - Marina Baquerizo Martinez
- Faculdade de Ciências Farmacêuticas, Department of Clinical Chemistry and Toxicology, Universidade de São Paulo (USP), São Paulo, Brazil
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Bannister SA, Kidd SP, Kirby E, Shah S, Thomas A, Vipond R, Elmore MJ, Telfer Brunton A, Marsh P, Green S, Silman NJ, Kempsell KE. Development and Assessment of a Diagnostic DNA Oligonucleotide Microarray for Detection and Typing of Meningitis-Associated Bacterial Species. High Throughput 2018; 7:ht7040032. [PMID: 30332776 PMCID: PMC6306750 DOI: 10.3390/ht7040032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/11/2018] [Accepted: 09/21/2018] [Indexed: 02/03/2023] Open
Abstract
Meningitis is commonly caused by infection with a variety of bacterial or viral pathogens. Acute bacterial meningitis (ABM) can cause severe disease, which can progress rapidly to a critical life-threatening condition. Rapid diagnosis of ABM is critical, as this is most commonly associated with severe sequelae with associated high mortality and morbidity rates compared to viral meningitis, which is less severe and self-limiting. We have designed a microarray for detection and diagnosis of ABM. This has been validated using randomly amplified DNA targets (RADT), comparing buffers with or without formamide, in glass slide format or on the Alere ArrayTubeTM (Alere Technologies GmbH) microarray platform. Pathogen-specific signals were observed using purified bacterial nucleic acids and to a lesser extent using patient cerebral spinal fluid (CSF) samples, with some technical issues observed using RADT and glass slides. Repurposing the array onto the Alere ArrayTubeTM platform and using a targeted amplification system increased specific and reduced nonspecific hybridization signals using both pathogen nucleic and patient CSF DNA targets, better revealing pathogen-specific signals although sensitivity was still reduced in the latter. This diagnostic microarray is useful as a laboratory diagnostic tool for species and strain designation for ABM, rather than for primary diagnosis.
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Affiliation(s)
| | - Stephen P Kidd
- Public Health England, Porton Down, Salisbury SP4 0JG, UK.
| | | | - Sonal Shah
- Public Health England, Porton Down, Salisbury SP4 0JG, UK.
| | - Anvy Thomas
- Public Health England, Porton Down, Salisbury SP4 0JG, UK.
| | - Richard Vipond
- Public Health England, Porton Down, Salisbury SP4 0JG, UK.
| | | | - Andrew Telfer Brunton
- Department of Clinical Microbiology, Royal Cornwall Hospitals NHS Trust, Penventinnie Lane, Treliske, Truro, Cornwall TR1 3LQ, UK.
| | - Peter Marsh
- Public Health England Laboratory Southampton, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK.
| | - Steve Green
- Public Health England Laboratory Southampton, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK.
| | - Nigel J Silman
- Public Health England, Porton Down, Salisbury SP4 0JG, UK.
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4
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Gutierrez M, Emmanuel PJ. Expanding Molecular Diagnostics for Central Nervous System Infections. Adv Pediatr 2018; 65:209-227. [PMID: 30053925 DOI: 10.1016/j.yapd.2018.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Mavel Gutierrez
- Department of Pediatrics, University of South Florida, College of Medicine, 2 Tampa General Circle, 5th Floor, STC 5016, Tampa, FL 33606, USA
| | - Patricia J Emmanuel
- Department of Pediatrics, University of South Florida, College of Medicine, 2 Tampa General Circle, 5th Floor, STC 5016, Tampa, FL 33606, USA.
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Enhanced Identification of Group B Streptococcus and Escherichia Coli in Young Infants with Meningitis Using the Biofire Filmarray Meningitis/Encephalitis Panel. Pediatr Infect Dis J 2017; 36:685-687. [PMID: 28114152 DOI: 10.1097/inf.0000000000001551] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
FilmArray Meningitis/Encephalitis (ME) polymerase chain reaction (PCR) panel was tested on 62 cerebrospinal fluid (CSF) samples from young infants (0-3 months) with suspected meningitis and compared with CSF cultures. Twelve CSF samples from 9 infants were positive by ME PCR panel (10 Group B Streptococcus (GBS) and 2 Escherichia coli) of which only 5 were positive by culture. The 7 CSF samples that were positive only by ME PCR panel were obtained from infants who had received prior antibiotic treatment. The ME PCR panel can be a useful tool in the rapid diagnosis of bacterial meningitis in pretreated young infants.
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McKenna JP, Cox C, Fairley DJ, Burke R, Shields MD, Watt A, Coyle PV. Loop-mediated isothermal amplification assay for rapid detection of Streptococcus agalactiae (group B streptococcus) in vaginal swabs - a proof of concept study. J Med Microbiol 2017; 66:294-300. [PMID: 28126051 DOI: 10.1099/jmm.0.000437] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Neonatal sepsis caused by Streptococcus agalactiae [group B streptococcus (GBS)] is a life-threatening condition, which is preventable if colonized mothers are identified and given antibiotic prophylaxis during labour. Conventional culture is time consuming and unreliable, and many available non-culture diagnostics are too complex to implement routinely at point of care. Loop-mediated isothermal amplification (LAMP) is a method that, enables the rapid and specific detection of target nucleic acid sequences in clinical materials without the requirement for extensive sample preparation. METHODOLOGY A prototype LAMP assay targeting GBS sip gene is described. RESULTS The assay was 100 % specific for GBS, with a limit of detection of 14 genome copies per reaction. The clinical utility of the LAMP assay for rapid direct molecular detection of GBS was determined by testing a total of 157 vaginal swabs with minimal sample processing using a rapid lysis solution. Compared to a reference quantitative real-time PCR assay, the direct LAMP protocol had a sensitivity and specificity of 95.4 and 100 %, respectively, with positive and negative predictive values of 100 and 98.3 %, respectively. Positive and negative likelihood ratios were infinity and 0.05, respectively. The direct LAMP method required a mean time of 45 min from the receipt of a swab to generation of a confirmed result, compared to 2 h 30 min for the reference quantitative real-time PCR test. CONCLUSION The direct LAMP protocol described is easy to perform, facilitating rapid and accurate detection of GBS in vaginal swabs. This test has a potential for use at point of care.
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Affiliation(s)
- James Patrick McKenna
- Regional Virus Laboratory, Department of Microbiology, Belfast Health and Social Care Trust, Belfast, UK
| | - Ciara Cox
- Regional Virus Laboratory, Department of Microbiology, Belfast Health and Social Care Trust, Belfast, UK
| | - Derek John Fairley
- Regional Virus Laboratory, Department of Microbiology, Belfast Health and Social Care Trust, Belfast, UK
| | - Rachael Burke
- Regional Virus Laboratory, Department of Microbiology, Belfast Health and Social Care Trust, Belfast, UK.,Centre for Experimental Medicine, Queens University Belfast, Belfast, UK
| | - Michael D Shields
- Centre for Experimental Medicine, Queens University Belfast, Belfast, UK.,Royal Belfast Hospital for Sick Children, Belfast Health and Social Care Trust, Belfast, UK
| | - Alison Watt
- Regional Virus Laboratory, Department of Microbiology, Belfast Health and Social Care Trust, Belfast, UK
| | - Peter Valentine Coyle
- Regional Virus Laboratory, Department of Microbiology, Belfast Health and Social Care Trust, Belfast, UK
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Morrissey SM, Nielsen M, Ryan L, Al Dhanhani H, Meehan M, McDermott S, O'Sullivan N, Doyle M, Gavin P, O'Sullivan N, Cunney R, Drew RJ. Group B streptococcal PCR testing in comparison to culture for diagnosis of late onset bacteraemia and meningitis in infants aged 7-90 days: a multi-centre diagnostic accuracy study. Eur J Clin Microbiol Infect Dis 2017; 36:1317-1324. [PMID: 28247153 DOI: 10.1007/s10096-017-2938-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/08/2017] [Indexed: 12/15/2022]
Abstract
The aim of this study was to compare an in-house real-time PCR assay, with bacterial culture as the reference, for the diagnosis of late onset group B Streptococcal (GBS) disease. This was a retrospective review. All children aged 7-90 days presenting to four paediatric centres that had a blood or CSF sample tested by GBS PCR were included. Of 7,686 blood and 2,495 cerebrospinal fluid (CSF) samples from patients of all ages received for PCR testing, 893 and 859 samples were eligible for the study, respectively. When compared to culture, the sensitivity of blood PCR was 65% (13/20) in comparison to the CSF PCR test which was 100% (5/5). Ten of 23 PCR-positive blood samples and 17 of 22 PCR-positive CSF samples were culture negative. The median threshold Ct values for culture-positive/PCR-positive CSF samples was lower than that of culture-negative/PCR-positive CSF samples (p = 0.08). Clinical details of 17 available cases that were culture negative/PCR positive were reviewed; seven were deemed to be definite cases, eight were probable and two were possible. The results showed that detection of GBS by PCR is useful for CSF samples from infants aged 7-90 days with suspected meningitis; however, analysis of blood samples by PCR is of limited value as a routine screening test for late onset GBS sepsis and should not replace bacterial culture.
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Affiliation(s)
- S M Morrissey
- Irish Meningitis and Sepsis Reference Laboratory, Temple Street Children's University Hospital, Dublin 1, Ireland
| | - M Nielsen
- Irish Meningitis and Sepsis Reference Laboratory, Temple Street Children's University Hospital, Dublin 1, Ireland
| | - L Ryan
- Department of Microbiology, University Hospital Waterford, Co. Waterford, Ireland
| | - H Al Dhanhani
- Departments of Microbiology and Paediatric Infectious Diseases, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland
| | - M Meehan
- Irish Meningitis and Sepsis Reference Laboratory, Temple Street Children's University Hospital, Dublin 1, Ireland
| | - S McDermott
- Department of Microbiology, Our Lady's Hospital, Co. Louth, Drogheda, Ireland
| | - N O'Sullivan
- Irish Meningitis and Sepsis Reference Laboratory, Temple Street Children's University Hospital, Dublin 1, Ireland
| | - M Doyle
- Department of Microbiology, University Hospital Waterford, Co. Waterford, Ireland
| | - P Gavin
- Departments of Microbiology and Paediatric Infectious Diseases, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland
| | - N O'Sullivan
- Departments of Microbiology and Paediatric Infectious Diseases, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland
| | - R Cunney
- Irish Meningitis and Sepsis Reference Laboratory, Temple Street Children's University Hospital, Dublin 1, Ireland
| | - R J Drew
- Irish Meningitis and Sepsis Reference Laboratory, Temple Street Children's University Hospital, Dublin 1, Ireland. .,Department of Microbiology, Rotunda Hospital, Dublin 1, Ireland. .,Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Dublin 2, Ireland. .,Rotunda Hospital, Parnell Square, Dublin 1, Ireland.
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8
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Abstract
BACKGROUND Microbial cultures for diagnosis of neonatal sepsis have low sensitivity and reporting delay. Advances in molecular microbiology have fostered new molecular assays that are rapid and may improve neonatal outcomes. OBJECTIVES To assess the diagnostic accuracy of various molecular methods for the diagnosis of culture-positive bacterial and fungal sepsis in neonates and to explore heterogeneity among studies by analyzing subgroups classified by gestational age and type of sepsis onset and compare molecular tests with one another. SEARCH METHODS We performed the systematic review as recommended by the Cochrane Diagnostic Test Accuracy Working Group. On 19 January 2016, we searched electronic bibliographic databases (the Cochrane Library, PubMed (from 1966), Embase (from 1982), and CINAHL (from 1982)), conference proceedings of the Pediatric Academic Societies annual conference (from 1990), clinical trial registries (ClinicalTrials.gov, International Standard Randomised Controlled Trial Number (ISRCTN) registry, and World Health Organization (WHO) International Clinical Trials Platform (ICTRP) Search portal), and Science Citation Index. We contacted experts in the field for studies. SELECTION CRITERIA We included studies that were prospective or retrospective, cohort or cross-sectional design, which evaluated molecular assays (index test) in neonates with suspected sepsis (participants) in comparison with microbial cultures (reference standard). DATA COLLECTION AND ANALYSIS Two review authors independently assessed the methodologic quality of the studies and extracted data. We performed meta-analyses using the bivariate and hierarchical summary receiver operating characteristic (HSROC) models and entered data into Review Manager 5. MAIN RESULTS Thirty-five studies were eligible for inclusion and the summary estimate of sensitivity was 0.90 (95% confidence interval (CI) 0.82 to 0.95) and of specificity was 0.93 (95% CI 0.89 to 0.96) (moderate quality evidence). We explored heterogeneity by subgroup analyses of type of test, gestational age, type of sepsis onset, and prevalence of sepsis and we did not find sufficient explanations for the heterogeneity (moderate to very low quality evidence). Sensitivity analyses by including studies that analyzed blood samples and by good methodology revealed similar results (moderate quality evidence). AUTHORS' CONCLUSIONS Molecular assays have the advantage of producing rapid results and may perform well as 'add-on' tests.
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Affiliation(s)
- Mohan Pammi
- Baylor College of MedicineSection of Neonatology, Department of Pediatrics6621, Fannin, MC.WT 6‐104HoustonTexasUSA77030
| | - Angela Flores
- Pediatrix Medical Group ‐ NW Houston Practice9250 Pinecroft St.The WoodlandsTexasUSA77380
| | - James Versalovic
- Texas Children’s Hospital and Baylor College of MedicinePathologyHoustonTexasUSA
| | - Mariska MG Leeflang
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsP.O. Box 22700AmsterdamNetherlands1100 DE
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Burke RM, McKenna JP, Cox C, Coyle PV, Shields MD, Fairley DJ. A comparison of different pre-lysis methods and extraction kits for recovery of Streptococcus agalacticae (Lancefield group B Streptococcus) DNA from whole blood. J Microbiol Methods 2016; 129:103-108. [DOI: 10.1016/j.mimet.2016.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
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10
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Su YL, Feng J, Li YW, Bai JS, Li AX. Development of a quantitative PCR assay for monitoring Streptococcus agalactiae colonization and tissue tropism in experimentally infected tilapia. JOURNAL OF FISH DISEASES 2016; 39:229-238. [PMID: 25858765 DOI: 10.1111/jfd.12358] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/10/2015] [Accepted: 01/10/2015] [Indexed: 06/04/2023]
Abstract
Streptococcus agalactiae has become one of the most important emerging pathogens in the aquaculture industry and has resulted in large economic losses for tilapia farms in China. In this study, three pairs of specific primers were designed and tested for their specificities and sensitivities in quantitative real-time polymerase chain reactions (qPCRs) after optimization of the annealing temperature. The primer pair IGS-s/IGS-a, which targets the 16S-23S rRNA intergenic spacer region, was finally chosen, having a detection limit of 8.6 copies of S. agalactiae DNA in a 20 μL reaction mixture. Bacterial tissue tropism was demonstrated by qPCR in Oreochromis niloticus 5 days post-injection with a virulent S. agalactiae strain. Bacterial loads were detected at the highest level in brain, followed by moderately high levels in kidney, heart, spleen, intestines, and eye. Significantly lower bacterial loads were observed in muscle, gill and liver. In addition, significantly lower bacterial loads were observed in the brain of convalescent O. niloticus 14 days post-injection with several different S. agalactiae strains. The qPCR for the detection of S. agalactiae developed in this study provides a quantitative tool for investigating bacterial tissue tropism in infected fish, as well as for monitoring bacterial colonization in convalescent fish.
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Affiliation(s)
- Y-L Su
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Haizhu District, Guangzhou, Guangdong Province, China
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong Province, China
| | - J Feng
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong Province, China
| | - Y-W Li
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Haizhu District, Guangzhou, Guangdong Province, China
| | - J-S Bai
- Guangzhou Airport Extry-Exit Inspection and Quarantine Bureau, Guangzhou, Guangdong Province, China
| | - A-X Li
- Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The School of Life Sciences, Sun Yat-sen University, Haizhu District, Guangzhou, Guangdong Province, China
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Real-time polymerase chain reaction and culture in the diagnosis of invasive group B streptococcal disease in infants: a retrospective study. Eur J Clin Microbiol Infect Dis 2015; 34:2413-20. [PMID: 26433745 DOI: 10.1007/s10096-015-2496-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/21/2015] [Indexed: 12/12/2022]
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.
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12
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Direct molecular versus culture-based assessment of Gram-positive cocci in biopsies of patients with major abscesses and diabetic foot infections. Eur J Clin Microbiol Infect Dis 2015; 34:1885-92. [PMID: 26143347 PMCID: PMC4545178 DOI: 10.1007/s10096-015-2428-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/11/2015] [Indexed: 12/20/2022]
Abstract
Major abscesses and diabetic foot infections (DFIs) are predominant subtypes of complicated skin and skin structure infections (cSSSIs), and are mainly caused by Staphylococcus aureus and β-hemolytic streptococci. This study evaluates the potential benefit of direct pathogen-specific real-time polymerase chain reaction (PCR) assays in the identification of causative organisms of cSSSIs. One-hundred and fifty major abscess and 128 DFI biopsy samples were collected and microbial DNA was extracted by using the Universal Microbe Detection kit for tissue samples. Pathogen-specific PCRs were developed for S. aureus and its virulence factor Panton–Valentine leukocidin (PVL), Streptococcus pyogenes, S. agalactiae, S. dysgalactiae, and the S. anginosus group. Identification by pathogen-specific PCRs was compared to routine culture and both methods were considered as the gold standard for determination of the sensitivity and specificity of each assay. Direct real-time PCR assays of biopsy samples resulted in a 34 % higher detection of S. aureus, 37 % higher detection of S. pyogenes, 18 % higher detection of S. agalactiae, 4 % higher detection of S. dysgalactiae subspecies equisimilis, and 7 % higher detection of the S. anginosus group, compared to routine bacterial culture. The presence of PVL was mainly confined to S. aureus isolated from major abscess but not DFI biopsy samples. In conclusion, our pathogen-specific real-time PCR assays had a higher yield than culture methods and could be an additional method for the detection of relevant causative pathogens in biopsies.
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Emonet S, Schrenzel J, Martinez de Tejada B. Molecular-based screening for perinatal group B streptococcal infection: implications for prevention and therapy. Mol Diagn Ther 2014; 17:355-61. [PMID: 23832874 DOI: 10.1007/s40291-013-0047-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Group B streptococci (GBS) are a leading cause of infectious neonatal morbidity and mortality. Timely and accurate identification of colonized pregnant women is imperative to implement intrapartum antibioprophylaxis (IAP) to reduce the risk of early neonatal sepsis. Current guidelines recommend screening for GBS carriage with vaginal-rectal cultures. However, cultures require 24-72 h, thus precluding their use for intrapartum screening and these are only performed at 35-37 weeks gestation. New rapid molecular-based tests can detect GBS within hours. They have the potential to be used intrapartum and to allow for selective IAP in women carrying GBS. An advantage is that they can sometimes be performed by non-laboratory staff in the labor suite, thus avoiding delays in sample transfers to the microbiology laboratory. Another possible use of molecular-based assays is for the diagnosis of neonatal sepsis, where tests with a short turnaround time and high sensitivity and specificity are crucial. In this situation, the detection of microorganisms once antibiotic therapy has already been started is important, as treatment is started immediately once sepsis is suspected without waiting for microbiological confirmation. In this article, we discuss the state-of-the-art molecular-based tests available for GBS screening during pregnancy, as well as their implications for IAP for the diagnosis and prevention of neonatal sepsis.
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Affiliation(s)
- Stéphane Emonet
- Department of Genetics and Laboratory Medicine, University Hospitals of Geneva and Faculty of Medicine, Geneva, Switzerland
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14
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Elling R, Hufnagel M, de Zoysa A, Lander F, Zumstein K, Krueger M, Henneke P. Synchronous recurrence of group B streptococcal late-onset sepsis in twins. Pediatrics 2014; 133:e1388-91. [PMID: 24709927 PMCID: PMC4006428 DOI: 10.1542/peds.2013-0426] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Group B Streptococcus (GBS) remains the leading cause of neonatal sepsis and meningitis in industrialized countries. Whereas the use of intrapartum antibiotic prophylaxis has led to a significant decline in early-onset sepsis, the incidence of late-onset sepsis has remained unchanged. Whether late-onset sepsis usually originates from established mucocutaneous GBS colonization of the infant or whether it results from an acute exogenous GBS infection remains controversial. Here we report on twins who both twice developed GBS sepsis in a strikingly parallel fashion, with both instances originating from a single hypervirulent GBS clone. Factored together, the presentation as cervical soft tissue infection in both cases, the synchronicity of the episodes, and the detection of GBS DNA in breast milk all strongly suggest an enteral mode of transmission with a short incubation period.
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Affiliation(s)
- Roland Elling
- Centers for Pediatrics and Adolescent Medicine and,Chronic Immunodeficiency, University Medical Center, Freiburg, Freiburg, Germany
| | | | - Aruni de Zoysa
- Respiratory and Vaccine Preventable Bacteria Reference Unit, Microbiology Services Division, Health Protection Agency, Colindale, London, United Kingdom; and
| | - Fabian Lander
- Centers for Pediatrics and Adolescent Medicine and,Clinic and Policlinic for Pediatrics and Adolescent Medicine, University Hospital Carl Gustav Carus, Technical University Dresden, Dresden, Germany
| | | | | | - Philipp Henneke
- Centers for Pediatrics and Adolescent Medicine and Chronic Immunodeficiency, University Medical Center, Freiburg, Freiburg, Germany;
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