1
|
Caballero Méndez A, Reynoso de la Rosa RA, Abreu Bencosme ME, Sosa Ortiz MN, Pichardo Beltré E, de la Cruz García DM, Piñero Santana NJ, Bacalhau de León JC. Development and performance evaluation of a qPCR-based assay for the fully automated detection of group B Streptococcus (GBS) on the Panther Fusion Open Access system. Microbiol Spectr 2024; 12:e0005724. [PMID: 38682931 DOI: 10.1128/spectrum.00057-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/26/2024] [Indexed: 05/01/2024] Open
Abstract
Streptococcus agalactiae [group B Streptococcus (GBS)] poses a major threat as the primary cause of early-onset neonatal invasive disease, particularly when mothers are colonized rectovaginally. Although culture remains the gold standard for antepartum GBS screening, quantitative polymerase chain reaction (qPCR) offers advantages in terms of sensitivity and turnaround time. The aim of this study was to validate the clinical utility of an automated qPCR laboratory-developed test (LDT) for antepartum GBS screening using the Panther Fusion Open Access system (Hologic, California, USA). The LDT targeted a conserved region of the GBS surface immunogenic protein gene, demonstrating no cross-reactivity and high coverage (99.82%-99.99%). The limit of detection (LoD) was 118 CFU/mL. Comparison with commercial qPCR assays (Panther Fusion GBS and VIASURE Streptococcus B Real-Time) revealed an overall agreement of 99.7%, with a robust Cohen's kappa coefficient of 0.992. Testing of 285 rectovaginal swabs from pregnant women and 15 external quality assessment samples demonstrated exceptional diagnostic performance of the LDT, achieving a diagnostic sensitivity and specificity of 100%, underscoring its accuracy. Prevalence and predictive values were also determined to reinforce test reliability. Our research highlights the limitations of culture-based screening and supports the suitability of our qPCR-based LDT for GBS detection in a clinical setting.IMPORTANCERectovaginal colonization by GBS is a major risk factor for early-onset invasive neonatal disease. The most effective approach to reducing the incidence of early-onset disease (EOD) has been described as universal screening, involving assessment of GBS colonization status in late pregnancy and intrapartum antibiotic prophylaxis. Despite its turnaround time and sensitivity limitations, culture remains the gold standard method for GBS screening. However, nucleic acid amplification-based tests, such as qPCR, have been utilized due to their speed and high sensitivity and specificity. This study validated the clinical usefulness of an automated qPCR-LDT for antepartum GBS screening through the Panther Fusion Open Access system (Hologic). Our study addresses the critical need for more robust, sensitive, and rapid strategies for GBS screening in pregnant women that could favorably impact the incidence of EOD.
Collapse
Affiliation(s)
- Andy Caballero Méndez
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Roberto A Reynoso de la Rosa
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Miguel E Abreu Bencosme
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Mayeline N Sosa Ortiz
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Eliezel Pichardo Beltré
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Darah M de la Cruz García
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Nelson J Piñero Santana
- Molecular Biology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| | - Joana C Bacalhau de León
- Microbiology Department, Referencia Laboratorio Clínico, Santo Domingo Oeste, Santo Domingo, Dominican Republic
| |
Collapse
|
2
|
Chen XJ, Wan TW, Chao QT, Teng LJ, Lee TF, Huang YT, Hsueh PR. Applicability of an in-house extraction protocol in a Bruker Biotyper matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system for the identification of Streptococcus agalactiae from broth-enriched vaginal/rectal swab specimens. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2023; 56:815-821. [PMID: 37330378 DOI: 10.1016/j.jmii.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/14/2023] [Accepted: 05/26/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND AND PURPOSE Early laboratory identification of group B Streptococcus (GBS, Streptococcus agalactiae) in the birth canal of pregnant women is critical for prompt administration of antimicrobial therapy and may further reduce the mortality rate due to GBS neonatal infection. METHODS A total of 164 vaginal/rectal swab specimens collected from pregnant women at 35-37 weeks of gestation were screened for GBS vaginal colonization. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS, Bruker Biotyper, Bruker Daltonik GmbH, Bremen, Germany) system was used to detect GBS from Carrot broth and LIM broth enrichment using an in-house extraction protocol. The results were compared to those by conventional broth-enriched culture/identification methods as the gold standard. BD MAX™ GBS assay (Becton Dickinson, Sparks, MD, USA) was also performed for Carrot broth-enriched specimen. Discordant results were investigated using the GeneXpert® GBS PCR assay (Cepheid Inc., Sunnyvale, CA, USA). RESULTS Using the extraction protocol, 33 (20.1%) of the 164 specimens were positive in Carrot broth, and 19 (11.6%) were positive in LIM broth. Using the culture protocol, 38 (23.2%) samples in Carrot broth and 35 (21.3%) in LIM broth were positive. The sensitivity, specificity, and positive and negative predictive values using the extraction protocol in Carrot broth and LIM broth compared to the gold standard conventional culture/identification method were 86.8% and 50.0%, 100% and 100%, 100% and 100%, and 96.2% and 86.9%, respectively. CONCLUSIONS The extraction protocol with MALDI-TOF MS from Carrot broth-enriched samples provides a more rapid turnaround time, lower cost, and acceptable sensitivity and specificity to correctly identify pathogens when compared to conventional culture/identification methods.
Collapse
Affiliation(s)
- Xiang-Jun Chen
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Tsai-Wen Wan
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Qiuo-Ting Chao
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Lee-Jene Teng
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Tai-Fen Lee
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
| | - Yu-Tsung Huang
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Po-Ren Hsueh
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Departments of Laboratory Medicine and Internal Medicine, China Medical University Hospital, School of Medicine, China Medical University, Taichung, Taiwan.
| |
Collapse
|
3
|
Peris MP, Martín-Saco G, Alonso-Ezcurra H, Escolar-Miñana C, Rezusta A, Acero R, Milagro-Beamonte A. Retrospective Study for the Clinical Evaluation of a Real-Time PCR Assay with Lyophilized and Ready-to-Use Reagents for Streptococcus agalactiae Detection in Prenatal Screening Specimens. Diagnostics (Basel) 2022; 12:diagnostics12092189. [PMID: 36140590 PMCID: PMC9497952 DOI: 10.3390/diagnostics12092189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/01/2022] [Accepted: 09/06/2022] [Indexed: 11/16/2022] Open
Abstract
Streptococcus agalactiae is a leading cause of sepsis and meningitis in newborns and young infants. Screening programs and intrapartum antibiotic prophylaxis have reduced early neonatal onset of disease. The aim of this study was to evaluate a molecular assay with lyophilized and ready-to-use reagents: VIASURE® Streptococcus B Real Time PCR detection kit (CerTest Biotec) (Viasure qPCR assay) compared to both the GBS culture and a molecular assay with separated and frozen reagents: Strep B Real-TM Quant (Sacace Biotecnologies®) (Sacace qPCR assay). A total of 413 vaginal−rectal swabs from women between the 35th and 37th weeks of pregnancy were processed. GBS culture was firstly achieved through Granada medium and Columbia CNA agar at 35 °C in aerobic conditions. Then, nucleic acid extraction was performed for subsequent molecular analysis using both commercial assays. Discordant results were resolved via bidirectional Sanger sequencing. Viasure qPCR assay clinical sensitivity was 0.97 (0.92−0.99) and specificity 1 (0.98−1). This retrospective study demonstrated the good clinical parameters and the strong overall agreement (99.3%) between the Viasure qPCR assay and both reference assays. Finally, the added value observed of the assay under study was the stabilized and ready-to-use format, reducing the number of time-consuming steps, permitting the storage at room temperature, facilitating transport, being environmentally respectful, and reducing additional costs.
Collapse
Affiliation(s)
- María Paz Peris
- Health Research Institute Aragón, 50009 Zaragoza, Spain
- Department of Animal Pathology, Faculty of Veterinary, University of Zaragoza, 50009 Zaragoza, Spain
- Correspondence: or ; Tel.: +34-976765500 (ext. 2801)
| | - Gloria Martín-Saco
- Health Research Institute Aragón, 50009 Zaragoza, Spain
- Miguel Servet University Hospital, Microbiology, 50009 Zaragoza, Spain
| | - Henar Alonso-Ezcurra
- Department of Microbiology, Paediatrics, Radiology, and Public Health, Faculty of Medicine, University of Zaragoza, 50009 Zaragoza, Spain
| | - Cristina Escolar-Miñana
- Department of Animal Production and Food Science, Faculty of Veterinary, University of Zaragoza, 50009 Zaragoza, Spain
| | - Antonio Rezusta
- Health Research Institute Aragón, 50009 Zaragoza, Spain
- Miguel Servet University Hospital, Microbiology, 50009 Zaragoza, Spain
| | - Raquel Acero
- Department of Design and Manufacturing Engineering, School of Engineering and Architecture, University of Zaragoza, 50009 Zaragoza, Spain
- Instituto de Investigación en Ingeniería de Aragón (I3A), University of Zaragoza, 50009 Zaragoza, Spain
| | - Ana Milagro-Beamonte
- Health Research Institute Aragón, 50009 Zaragoza, Spain
- Miguel Servet University Hospital, Microbiology, 50009 Zaragoza, Spain
| |
Collapse
|
4
|
Tanno D, Saito K, Ohashi K, Toyokawa M, Yamadera Y, Shimura H. Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry with Time-of-Flight Peak Analysis for Rapid and Accurate Detection of Group B Streptococcus in Pregnant Women. Microbiol Spectr 2022; 10:e0173221. [PMID: 35435738 PMCID: PMC9241660 DOI: 10.1128/spectrum.01732-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 03/30/2022] [Indexed: 11/20/2022] Open
Abstract
Severe infections in neonates caused by Streptococcus agalactiae, Group B Streptococcus (GBS), are often associated with GBS transmission from their mothers during labor or birth. Hence, it is necessary to develop a universal method for screening vaginal-rectal GBS colonization in pregnant women worldwide. A subculture of vaginal-rectal swabs using a selective enrichment broth and an agar plate is conventionally recommended for GBS screening. However, infants born to mothers who are GBS negative on subculture sometimes contract GBS infections. Therefore, we developed another method with high sensitivity for GBS screening. A total of 178 vaginal-rectal swabs from pregnant women were inoculated into the enrichment broth, of which 126 were suspected of containing GBS due to the change in the color of the broth. The subculture results were positive for GBS in 34 (27.0%) swabs. Each broth was then analyzed using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Analysis of the TOF peaks specific to GBS revealed 45 (35.7%) swabs as GBS positive. Of the 11 GBS positive samples on TOF peak analysis but negative on subculture, S. agalactiae gene targets were detected through PCR in 4 samples. MALDI detection with analysis of peaks of TOF (MDAPT) can detect GBS directly from cultured broth with high sensitivity. MDAPT can be an alternative method for GBS screening in pregnant women and contribute to the prevention of severe GBS infectious diseases in neonates. IMPORTANCE As previously reported, 10%-30% of pregnant women carry Streptococcus agalactiae, Group B Streptococcus (GBS), in their vagina or rectum, and approximately 50% of them vertically transmit GBS to their neonates during labor or birth. Moreover, 1%-2% of the GBS-transmitted neonates develop severe GBS infectious diseases, which have a mortality rate of 19.2% in a preterm infant and 2.1% in a full-term infant. Hence, universal screening for GBS colonization in pregnant women is conducted worldwide using the subculture procedure; however, infants born to GBS negative mothers sometimes contract GBS infections. Therefore, other laboratory techniques are required for detecting GBS more accurately. The proposed method "MALDI detection with analysis of peaks of TOF (MDAPT)" detects GBS directly from cultured broth with high sensitivity. Therefore, it can be an alternative method for GBS screening in pregnant women, thereby contributing to the prevention of severe GBS infectious diseases in neonates.
Collapse
Affiliation(s)
- Daiki Tanno
- Department of Clinical Laboratory, Fukushima Medical University Hospital, Fukushima, Japan
- Department of Laboratory Medicine, School of Medicine, Fukushima Medical University, Fukushima, Japan
- Department of Clinical Laboratory Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Kyoichi Saito
- Department of Laboratory Medicine, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Kazutaka Ohashi
- Department of Clinical Laboratory, Fukushima Medical University Hospital, Fukushima, Japan
| | - Masahiro Toyokawa
- Department of Clinical Laboratory, Fukushima Medical University Hospital, Fukushima, Japan
- Department of Laboratory Medicine, School of Medicine, Fukushima Medical University, Fukushima, Japan
- Department of Clinical Laboratory Sciences, School of Health Sciences, Fukushima Medical University, Fukushima, Japan
| | - Yukio Yamadera
- Department of Clinical Laboratory, Fukushima Medical University Hospital, Fukushima, Japan
| | - Hiroki Shimura
- Department of Laboratory Medicine, School of Medicine, Fukushima Medical University, Fukushima, Japan
| |
Collapse
|
5
|
Xu S, Qiu X, Hou X, Zhou H, Chen D, Wang X, Han L, Li D, Sun L, Ji X, Li M, Zhang J, Li M, Li Z. Direct detection of Corynebacterium striatum, Corynebacterium propinquum, and Corynebacterium simulans in sputum samples by high-resolution melt curve analysis. BMC Infect Dis 2021; 21:21. [PMID: 33413116 PMCID: PMC7788810 DOI: 10.1186/s12879-020-05633-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/19/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pulmonary infections caused by non-diphtheriae corynebacteria are increasing. However, rapid identification of Corynebacterium species poses a challenge due to the low genetic variation within the genus. METHODS Three reference strains and 99 clinical isolates were used in this study. A qPCR followed by high-resolution melting (HRM) targeting ssrA was performed to simultaneously identify C. striatum, C. propinquum and C. simulans. To further evaluate this assay's performance, 88 clinical sputum samples were tested by HRM and the detection results were compared with those of the traditional culture method and multiple cross-displacement amplification (MCDA) assay. RESULTS The melting curve produced by a pair of universal primers generated species-specific HRM curve profiles and could distinguish the three target species from other related bacteria. The limit of detection of HRM assay for DNA from the three purified Corynebacterium species was 100 fg. Compared with the culture method, HRM detected 22 additional positive specimens, representing a 23.9% relative increase in detection rate. The HRM assay had 98.4% (95% confidence interval [CI], 90.5-99.9%) sensitivity and 100% (95% CI, 82.8-100%) specificity. Additionally, 95.5% concordance between HRM and MCDA (κ = 0.89 [95% CI, 0.79-0.99]) was noted. CONCLUSIONS The HRM assay was a simple, rapid, sensitive, and specific diagnostic tool for detecting C. striatum, C. propinquum, and C. simulans, with the potential to contribute to early diagnosis, epidemiological surveillance, and rapid response to outbreak.
Collapse
Affiliation(s)
- Shuai Xu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiaotong Qiu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xuexin Hou
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Haijian Zhou
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Dongke Chen
- Department, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Xuebing Wang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Lichao Han
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Dan Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Lina Sun
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xingzhao Ji
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Minghui Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jingshan Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Mengtong Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zhenjun Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
| |
Collapse
|
6
|
Comparison of Three Nucleic Acid Amplification Tests and Culture for Detection of Group B Streptococcus from Enrichment Broth. J Clin Microbiol 2019; 57:JCM.01958-18. [PMID: 30944190 PMCID: PMC6535594 DOI: 10.1128/jcm.01958-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/16/2019] [Indexed: 12/17/2022] Open
Abstract
Colonization of the gastrointestinal and genitourinary tracts of pregnant women with group B Streptococcus (GBS) can result in vertical transmission to neonates during labor/delivery. GBS infections in neonates can cause severe complications, such as sepsis, meningitis, and pneumonia. Accurate detection is critical because administration of intrapartum antibiotics can significantly reduce transmission. We compared the clinical sensitivities of three nucleic acid amplification tests (NAATs), the Hologic Panther Fusion GBS, Luminex Aries GBS, and Cepheid Xpert GBS LB assays, to that of the standard of care culture method recommended for GBS screening using 500 vaginal-rectal swab specimens after 18 to 24 h of broth enrichment. We identified 108 positive specimens (21.6%) by culture, while at least 1 of the 3 NAATs was positive for GBS in 155 specimens (31.0%). All 108 specimens positive by culture were also detected by the Panther Fusion assay, while 107/108 (99.1%) were detected by the Cepheid Xpert and Luminex Aries assays. Of the 61 specimens positive by at least 1 NAAT but negative by culture, 24 (39.3%) were positive by all 3 NAATs, suggesting that they represent true positives (TPs). NAATs offer less hands-on time, greater throughput, faster time to result, and potentially greater sensitivity than culture methods, and they should be considered the new gold standard for intrapartum GBS screening.
Collapse
|
7
|
Assessment of conventional PCR and real-time PCR compared to the gold standard method for screening Streptococcus agalactiae in pregnant women. Braz J Infect Dis 2018; 22:449-454. [PMID: 30471244 PMCID: PMC9425650 DOI: 10.1016/j.bjid.2018.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 05/11/2018] [Accepted: 09/13/2018] [Indexed: 11/23/2022] Open
Abstract
Group B Streptococcus is a causative agent of invasive neonatal infections. Maternal colonization by Streptococcus agalactiae is a necessary condition for vertical transmission, with efficient screening of pregnant women playing an essential role in the prevention of neonatal infections. In this study, we aimed to compare the performance of conventional polymerase chain reaction and real-time PCR assays as screening methods for S. agalactiae in pregnant women against the microbiological culture method considered as the gold-standard. A total of 130 samples from pregnant women were analyzed for sensitivity, specificity, positive predictive value, and negative predictive value. Statistical analysis was performed using the SPSS software, version 20.0. The verified colonization rate was 3.8% with the gold-standard, 17.7% with conventional PCR assay, and 29.2% with the real-time PCR test. The trials with conventional PCR and real-time PCR had a sensitivity of 100% and a specificity of 85.6% and 73.6%, respectively. The real-time PCR assay had a better performance compared to the gold-standard and a greater detection rate of colonization by S. agalactiae compared to conventional PCR assay. With its quick results, it would be suitable for using in routine screenings, contributing to the optimization of preventive approaches to neonatal S. agalactiae infection.
Collapse
|
8
|
Pyclik M, Górska S, Brzozowska E, Dobrut A, Ciekot J, Gamian A, Brzychczy-Włoch M. Epitope Mapping of Streptococcus agalactiae Elongation Factor Tu Protein Recognized by Human Sera. Front Microbiol 2018; 9:125. [PMID: 29467739 DOI: 10.3389/fmicb.2018.00125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/18/2018] [Indexed: 12/26/2022] Open
Abstract
The elongation factor Tu has been identified as one of the most immunoreactive proteins that was recognized by human sera of GBS (group B streptococcus) positive patients. In this paper, we present the polypeptide-specific epitopes of the bacterial protein that are recognized by human antibodies: 28LTAAITTVLARRLP41 (peptide no. 3) and 294GQVLAKPGSINPHTKF309 (peptide no. 21). To determine the shortest amino acid sequence recognized by antibodies, truncation peptide libraries were prepared using the PEPSCAN method. The analysis of immunoreactivity of peptides with sera of GBS positive and negative women revealed that the most immunoreactive sequence was 306HTKF309. Moreover, we observed that this sequence also showed the highest specificity which was based on ratio of reactivity with sera of GBS positive relative to sera of GBS negative patients. Epitope was synthetized on Wang resin with the Fmoc strategy. Our results open the possibility to use 306HTKF309 peptide in diagnostic assays to determine Streptococcus agalactiae infection in humans.
Collapse
Affiliation(s)
- Marcelina Pyclik
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Sabina Górska
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Ewa Brzozowska
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Anna Dobrut
- Chair of Microbiology, Department of Molecular Medical Microbiology, Jagiellonian University Medical College, Krakow, Poland
| | - Jarosław Ciekot
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Andrzej Gamian
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Monika Brzychczy-Włoch
- Chair of Microbiology, Department of Molecular Medical Microbiology, Jagiellonian University Medical College, Krakow, Poland
| |
Collapse
|
9
|
Park SY, Kim SY, Choi WJ, Kim SH, Hong SG. Diagnostic Accuracy and Detection Rate of Real-Time PCR for Detection of Group B Streptococcal Colonization in Pregnant Women: Systemic Review of Literature and Meta-Analysis. ANNALS OF CLINICAL MICROBIOLOGY 2017. [DOI: 10.5145/acm.2017.20.2.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Sun Young Park
- Division of New Health Technology Assessment, National Evidence-Based Healthcare Collaborating Agency, Seoul, Korea
| | - So Young Kim
- Division of New Health Technology Assessment, National Evidence-Based Healthcare Collaborating Agency, Seoul, Korea
| | - Won Jung Choi
- Division of New Health Technology Assessment, National Evidence-Based Healthcare Collaborating Agency, Seoul, Korea
| | - Seok-Hyun Kim
- Division of New Health Technology Assessment, National Evidence-Based Healthcare Collaborating Agency, Seoul, Korea
| | - Seong Geun Hong
- Department of Laboratory Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Korea
| |
Collapse
|
10
|
Bacterial Infections. MOLECULAR PATHOLOGY IN CLINICAL PRACTICE 2016. [PMCID: PMC7123846 DOI: 10.1007/978-3-319-19674-9_49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular techniques have revolutionized the detection and identification of microorganisms. Real-time PCR has allowed for the rapid and accurate detection of MRSA, VRE, and group B Streptococcus. The identification of difficult and slow-growing organisms has been expedited by sequence-based methods such as 16S rRNA gene sequencing. Rapid identification of organisms and detection of resistance markers directly from positive blood culture bottles has become a reality. Finally, a transformation is taking place with the introduction of MALDI-TOF into clinical laboratories that promises to improve the accuracy and speed of bacterial and fungal identifications by days. The advantages of these methodologies and their associated clinical applications, along with their inherent pitfalls and problems, are elucidated in this chapter.
Collapse
|
11
|
Goudarzi G, Ghafarzadeh M, Shakib P, Anbari K. Culture and Real-Time PCR Based Maternal Screening and Antibiotic Susceptibility for Group B Streptococcus: An Iranian Experience. Glob J Health Sci 2015; 7:233-9. [PMID: 26153188 PMCID: PMC4803879 DOI: 10.5539/gjhs.v7n6p233] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 02/25/2015] [Indexed: 11/29/2022] Open
Abstract
Introduction: Vertical Transmission of group B streptococcus (GBS) from a vagina colonized mother to her infant upon rupture of membranes (ROM) or after the onset of labor can cause life-threatening infections in newborn. Although intrapartum antibiotic prophylaxis (IAP) can significantly decrease neonatal GBS diseases, this issue has potentiated the emergence of antibiotic resistance strains. Our study examined the colonization rate of GBS using real-time PCR and culture methods, and trends in antibiotic resistance of GBS isolates obtained from pregnant women in Khorramabad, Iran. Methods: In this cross-sectional study, two vaginal-rectal swabs were collected and analyzed separately from 100 pregnant women at 35-37 weeks of gestation by convenience sampling method. The specimens were subjected to GBS detection using real-time PCR assay and standard culture. Susceptibility pattern of the GBS isolates was examined using the disk diffusion method. Results: GBS carriage rate was 17% and 19% using culture and real-time PCR, respectively. In six samples, the culture was positive and the real-time PCR was negative. Sensitivity and specificity for real-time PCR were 72.7% and 96.1%, respectively using culture as the gold standard. Amongst twenty-two isolates examined, 100% resistance to erythromycin and clindamycin was observed. One isolate (4%) exhibited resistance to penicillin. Conclusion: Considering the relatively high GBS carriage rate in Khorramabad, routine antepartum screening for GBS is recommended. Penicillin can remain the antibiotic of choice for IAP; however, in penicillin-allergic mothers, vancomycin can be an alternative antibiotic.
Collapse
Affiliation(s)
- Gholamreza Goudarzi
- School of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran.
| | | | | | | |
Collapse
|
12
|
Comparison of the AmpliVue, BD Max System, and illumigene Molecular Assays for Detection of Group B Streptococcus in Antenatal Screening Specimens. J Clin Microbiol 2015; 53:1938-41. [PMID: 25788551 DOI: 10.1128/jcm.00261-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/15/2015] [Indexed: 11/20/2022] Open
Abstract
The performances of the AmpliVue, BD Max, and illumigene group B Streptococcus (GBS) nucleic acid amplification tests (NAATs) were compared to that of enriched culture for detection of GBS in antenatal screening specimens. Two hundred specimens were tested simultaneously with the NAATs, following 18 to 24 h of Lim broth enrichment; 15% of specimens were culture positive for GBS, whereas 31.5% were positive by at least one NAAT. All three NAATs were more sensitive (sensitivity, 90.9 to 100%) than culture (sensitivity, 53.6%).
Collapse
|
13
|
Ahmadzia HK, Heine RP. Diagnosis and management of group B streptococcus in pregnancy. Obstet Gynecol Clin North Am 2014; 41:629-47. [PMID: 25454995 DOI: 10.1016/j.ogc.2014.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Group B streptococcus (GBS) can cause significant maternal and neonatal morbidity. Over the past 30 years, reductions in early-onset GBS neonatal sepsis in the United States have been attributable to the guidelines from the Centers for Disease Control and Prevention for antepartum screening and treating this organism during labor. This article highlights the clinical implications, screening, diagnosis, prophylactic interventions, and future therapies for mothers with GBS during the peripartum period.
Collapse
Affiliation(s)
- Homa K Ahmadzia
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Duke University Medical Center, DUMC 3967, Durham, NC 27710, USA
| | - R Phillips Heine
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Duke University Medical Center, DUMC 3967, Durham, NC 27710, USA.
| |
Collapse
|
14
|
Estimation of Group B Streptococcus Colonization in High-Risk Neonates by PCR and Standard Culture. ARCHIVES OF PEDIATRIC INFECTIOUS DISEASES 2014. [DOI: 10.5812/pedinfect.17345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
15
|
Poncelet-Jasserand E, Forges F, Varlet MN, Chauleur C, Seffert P, Siani C, Pozzetto B, Ros A. Reduction of the use of antimicrobial drugs following the rapid detection ofStreptococcus agalactiaein the vagina at delivery by real-time PCR assay. BJOG 2013; 120:1098-108. [DOI: 10.1111/1471-0528.12138] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2012] [Indexed: 11/29/2022]
Affiliation(s)
- E Poncelet-Jasserand
- Department of Obstetrics; Gynaecology and Reproductive Medicine; University-Hospital of Saint-Etienne; France
| | - F Forges
- Unit of Clinical Research, Innovation and Pharmacology; INSERM CIE3; University-Hospital of Saint-Etienne; France
| | - M-N Varlet
- Department of Obstetrics; Gynaecology and Reproductive Medicine; University-Hospital of Saint-Etienne; France
| | - C Chauleur
- Department of Obstetrics; Gynaecology and Reproductive Medicine; University-Hospital of Saint-Etienne; France
| | - P Seffert
- Department of Obstetrics; Gynaecology and Reproductive Medicine; University-Hospital of Saint-Etienne; France
| | - C Siani
- Research Laboratory in Knowledge Engineering (ERIC); University of Lyon; Institute of Pharmaceutical and Biological Sciences (ISPB) of Lyon; France
| | | | - A Ros
- Department of Microbiology; Hôpital Nord; University-Hospital of Saint-Etienne; France
| |
Collapse
|
16
|
Performance of RT-PCR in the detection of Streptococcus agalactiae in the anogenital tract of pregnant women. Arch Gynecol Obstet 2012; 286:1437-42. [DOI: 10.1007/s00404-012-2498-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 07/23/2012] [Indexed: 10/28/2022]
|
17
|
Schwartz J, Robinson-Dunn B, Makin J, Boyanton BL. Evaluation of the BD MAX GBS assay to detect Streptococcus group B in LIM broth–enriched antepartum vaginal–rectal specimens. Diagn Microbiol Infect Dis 2012; 73:97-8. [DOI: 10.1016/j.diagmicrobio.2012.01.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/25/2012] [Accepted: 01/26/2012] [Indexed: 10/28/2022]
|
18
|
How can the microbiologist help in diagnosing neonatal sepsis? Int J Pediatr 2012; 2012:120139. [PMID: 22319539 PMCID: PMC3272815 DOI: 10.1155/2012/120139] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 09/15/2011] [Accepted: 11/29/2011] [Indexed: 01/23/2023] Open
Abstract
Neonatal sepsis can be classified into two subtypes depending upon whether the onset of symptoms is before 72 hours of life (early-onset neonatal sepsis—EONS) or later (late-onset neonatal sepsis—LONS). These definitions have contributed greatly to diagnosis and treatment by identifying which microorganisms are likely to be responsible for sepsis during these periods and the expected outcomes of infection. This paper focuses on the tools that microbiologist can offer to diagnose and eventually prevent neonatal sepsis. Here, we discuss the advantages and limitation of the blood culture, the actual gold standard for sepsis diagnosis. In addition, we examine the utility of molecular techniques in the diagnosis and management of neonatal sepsis.
Collapse
|
19
|
Molecular Detection of Group B
Streptococcus. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
20
|
|
21
|
El Aila NA, Tency I, Claeys G, Verstraelen H, Deschaght P, Decat E, Lopes dos Santos Santiago G, Cools P, Temmerman M, Vaneechoutte M. Comparison of culture with two different qPCR assays for detection of rectovaginal carriage of Streptococcus agalactiae (group B streptococci) in pregnant women. Res Microbiol 2011; 162:499-505. [DOI: 10.1016/j.resmic.2011.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 03/11/2011] [Indexed: 11/28/2022]
|
22
|
Munson E, Napierala M, Munson KL, Culver A, Hryciuk JE. Temporal characterization of carrot broth-enhanced real-time PCR as an alternative means for rapid detection of Streptococcus agalactiae from prenatal anorectal and vaginal screenings. J Clin Microbiol 2010; 48:4495-500. [PMID: 20980578 PMCID: PMC3008479 DOI: 10.1128/jcm.01734-10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/05/2010] [Accepted: 10/13/2010] [Indexed: 11/20/2022] Open
Abstract
Analysis of overnight carrot broth culture using the BD GeneOhm StrepB assay (carrot broth-enhanced PCR) yields increased sensitivity compared to that of carrot broth culture alone for the detection of Streptococcus agalactiae. We investigated the prospect of reducing the carrot broth incubation time prior to PCR performance. In vitro experimentation demonstrated that carrot broth-enhanced PCR nominally detected 10 CFU S. agalactiae after 4 h of carrot broth incubation with competitive flora. Detection rates improved with inocula of 100 and 1,000 CFU S. agalactiae, with the majority of these aliquots demonstrating detection after 2 h of carrot broth incubation. Carrot broth was prospectively inoculated with clinical vaginal/anorectal swabs, with 500-μl aliquots collected. Early aliquots from 227 specimens were subjected to carrot broth-enhanced PCR (early-aliquot carrot broth-enhanced PCR) in instances of subsequent positive carrot broth culture or positive overnight clinical carrot broth-enhanced PCR. The S. agalactiae detection rate by early-aliquot carrot broth-enhanced PCR (66.1%) exceeded that observed for 227 remnant swabs retrospectively tested by direct swab PCR (56.4%; P=0.03). Early-aliquot carrot broth-enhanced PCR detection rate differences were most pronounced in aliquots from 83 carrot broth aliquots collected after 6 h (84.3%) compared to detection rates from either direct swab PCR of these samples (51.8%; P<0.0002) or early-aliquot carrot broth-enhanced PCR of 144 carrot broth aliquots collected after fewer than 6 h of incubation (55.6%; P<0.0002). Enhanced sensitivity of early-aliquot carrot broth-enhanced PCR versus direct swab PCR suggests that this assay could serve as a surrogate rapid detection method facilitating the prevention of group B streptococcal disease.
Collapse
Affiliation(s)
- Erik Munson
- Wheaton Franciscan Laboratory, 11020 West Plank Court, Suite 100, Wauwatosa, WI 53226, USA.
| | | | | | | | | |
Collapse
|
23
|
Castellano-Filho DS, da Silva VL, Nascimento TC, de Toledo Vieira M, Diniz CG. Detection of Group B Streptococcus in Brazilian pregnant women and antimicrobial susceptibility patterns. Braz J Microbiol 2010; 41:1047-55. [PMID: 24031585 PMCID: PMC3769761 DOI: 10.1590/s1517-838220100004000024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 04/19/2010] [Accepted: 06/21/2010] [Indexed: 11/22/2022] Open
Abstract
Group B Streptococcus (GBS) is still not routinely screened during pregnancy in Brazil, being prophylaxis and empirical treatment based on identification of risk groups. This study aimed to investigate GBS prevalence in Brazilian pregnant women by culture or polymerase chain reaction (PCR) associated to the enrichment culture, and to determine the antimicrobial susceptibility patterns of isolated bacteria, so as to support public health policies and empirical prophylaxis. After an epidemiological survey, vaginal and anorectal specimens were collected from 221 consenting laboring women. Each sample was submitted to enrichment culture and sheep blood agar was used to isolate suggestive GBS. Alternatively, specific PCR was performed from enrichment cultures. Antimicrobial susceptibility patterns were determined for isolated bacteria by agar diffusion method. No risk groups were identified. Considering the culture-based methodology, GBS was detected in 9.5% of the donors. Twenty five bacterial strains were isolated and identified. Through the culture-PCR methodology, GBS was detected in 32.6% specimens. Bacterial resistance was not detected against ampicillin, cephazolin, vancomycin and ciprofloxacin, whereas 22.7% were resistant to erythromycin and 50% were resistant to clindamycin. GBS detection may be improved by the association of PCR and enrichment culture. Considering that colony selection in agar plates may be laboring and technician-dependent, it may not reflect the real prevalence of streptococci. As in Brazil prevention strategies to reduce the GBS associated diseases have not been adopted, prospective studies are needed to anchor public health policies especially considering the regional GBS antimicrobial susceptibility patterns.
Collapse
Affiliation(s)
- Didier Silveira Castellano-Filho
- Departamento de Parasitologia, Microbiologia e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora , Juiz de Fora, MG , Brasil
| | | | | | | | | |
Collapse
|
24
|
Multicenter evaluation of the BD Max GBS assay for detection of group B streptococci in prenatal vaginal and rectal screening swab specimens from pregnant women. J Clin Microbiol 2010; 48:4239-41. [PMID: 20826650 DOI: 10.1128/jcm.00947-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new integrated extraction and real-time PCR-based system for the detection of group B streptococci in antepartum screening samples enriched in Lim broth was compared to the CDC-recommended culture method. The BD Max GBS assay exhibited acceptable sensitivity (95%) and specificity (96.7%) compared to those of the culture method in this multisite evaluation.
Collapse
|
25
|
Jordan JA, Hall G, Davis T. Multicenter study evaluating performance of the Smart Group B Streptococcus (GBS) assay using an enrichment protocol for detecting GBS colonization in patients in the antepartum period. J Clin Microbiol 2010; 48:3193-7. [PMID: 20668132 PMCID: PMC2937680 DOI: 10.1128/jcm.00106-10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 02/22/2010] [Accepted: 07/16/2010] [Indexed: 11/20/2022] Open
Abstract
Group B streptococcus (GBS) remains the leading cause of infectious morbidity and mortality in infants born in the United States, especially among black infants. Because a newborn can acquire GBS during and after delivery, the Centers for Disease Control and Prevention (CDC) recommends that pregnant women be screened for rectovaginal GBS colonization during the antepartum period between weeks 35 and 37 of gestation and, if they are colonized, that intrapartum antibiotic prophylaxis be administered. A prospective investigational study was undertaken from 2 May 2006 to 14 August 2006 at three sites to establish the performance characteristics of the Smart GBS LB assay on the SmartCycler II system for detecting GBS colonization in subjects in the antepartum period from combined vaginal/rectal swab-based specimens after broth enrichment. Results were compared to broth enrichment culture and to the predicate device, the BD GeneOhm StrepB direct assay. The collected specimens were randomized for swab testing order. Each swab sample was processed simultaneously by culture, Smart GBS LB assay, and the BD GeneOhm StrepB assay. A total of 310 subjects were enrolled, with 306 subject results included in the study. Compared to enrichment culture, the Smart GBS LB assay demonstrated a sensitivity, specificity, positive predictive value, and negative predictive value of 98.6%, 90.4%, 77.1%, and 99.5%, respectively. The Smart GBS LB assay demonstrated substantially equivalent or better performance than culture or the predicate device. Screening of broth enrichment fluids by nucleic acid amplification testing requires careful handling during sample processing to avoid possible contamination.
Collapse
Affiliation(s)
- Jeanne A Jordan
- Department of Epidemiology and Biostatistics, School of Public Health and Health Services, The George Washington University, 2300 Eye St., NW, 231 Ross Hall, Washington, DC 20037, USA.
| | | | | |
Collapse
|
26
|
Real-time PCR assay provides reliable assessment of intrapartum carriage of group B Streptococcus. J Clin Microbiol 2010; 48:3095-9. [PMID: 20592137 DOI: 10.1128/jcm.00594-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to determine the reliability of the real-time PCR assay for determining the group B Streptococcus (GBS) status of women in labor. In this prospective study we compared the results of culture and PCR testing of vaginal and rectal samples collected by nursing staff when women were in labor. Patients' charts were also reviewed to obtain relevant information about pregnancy risk factors. Our results demonstrated a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 90.5%, 96.1%, 86.4%, and 97.4%, respectively, for rapid PCR. Of the 196 women evaluated, 29 (14.8%) presented with unknown GBS status, 11 (37.9%) of whom received unnecessary intrapartum antibiotics. The rapid real-time PCR test was robust and was able to reliably detect the presence of GBS in women in labor within 1 h of specimen submission to the laboratory. We recommend that the rapid PCR test be targeted to women who present in labor with unknown GBS status. In cases where the laboratory does not offer 24-h availability of testing, sample collection followed by PCR testing the next morning is still valuable and provides reliable results 24 to 48 h faster than culture and will aid appropriate decision-making regarding continuing or stopping antibiotics for neonates of women with unknown GBS status.
Collapse
|
27
|
Wernecke M, Mullen C, Sharma V, Morrison J, Barry T, Maher M, Smith T. Evaluation of a novel real-time PCR test based on the ssrA gene for the identification of group B streptococci in vaginal swabs. BMC Infect Dis 2009; 9:148. [PMID: 19732424 PMCID: PMC2755475 DOI: 10.1186/1471-2334-9-148] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 09/04/2009] [Indexed: 11/10/2022] Open
Abstract
Background Despite the implementation of prevention guidelines, early-onset group B streptococci (GBS) disease remains a cause of neonatal morbidity and mortality worldwide. Strategies to identify women who are at risk of transmitting GBS to their infant and the administration of intrapartum antibiotics have greatly reduced the incidence of neonatal GBS disease. However, there is a requirement for a rapid diagnostic test for GBS that can be carried out in a labour ward setting especially for women whose GBS colonisation status is unknown at the time of delivery. We report the design and evaluation of a real-time PCR test (RiboSEQ GBS test) for the identification of GBS in vaginal swabs from pregnant women. Methods The qualitative real-time PCR RiboSEQ GBS test was designed based on the bacterial ssrA gene and incorporates a competitive internal standard control. The analytical sensitivity of the test was established using crude lysate extracted from serial dilutions of overnight GBS culture using the IDI Lysis kit. Specificity studies were performed using DNA prepared from a panel of GBS strains, related streptococci and other species found in the genital tract environment. The RiboSEQ GBS test was evaluated on 159 vaginal swabs from pregnant women and compared with the GeneOhm™ StrepB Assay and culture for the identification of GBS. Results The RiboSEQ GBS test is specific and has an analytical sensitivity of 1-10 cell equivalents. The RiboSEQ GBS test was 96.4% sensitive and 95.8% specific compared to "gold standard" culture for the identification of GBS in vaginal swabs from pregnant women. In this study, the RiboSEQ GBS test performed slightly better than the commercial BD GeneOhm™ StrepB Assay which gave a sensitivity of 94.6% and a specificity of 89.6% compared to culture. Conclusion The RiboSEQ GBS test is a valuable method for the rapid, sensitive and specific detection of GBS in pregnant women. This study also validates the ssrA gene as a suitable and versatile target for nucleic acid-based diagnostic tests for bacterial pathogens.
Collapse
Affiliation(s)
- Martina Wernecke
- Molecular Diagnostics Research Group, National Centre for Biomedical Engineering Science, Galway, Ireland.
| | | | | | | | | | | | | |
Collapse
|
28
|
Smith D, Perry JD, Laine L, Galloway A, Gould FK. Comparison of BD GeneOhm real-time polymerase chain reaction with chromogenic and conventional culture methods for detection of group B Streptococcus in clinical samples. Diagn Microbiol Infect Dis 2008; 61:369-72. [PMID: 18440176 DOI: 10.1016/j.diagmicrobio.2008.03.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 03/13/2008] [Accepted: 03/18/2008] [Indexed: 10/22/2022]
Abstract
A total of 200 antenatal high vaginal swabs were screened for the presence of group B Streptococcus (GBS) using a conventional culture method (recommended by Centers for Disease Control and Prevention). Screening was also performed by using a new chromogenic agar, chromID Strepto B, and by using the BD GeneOhm StrepB real-time polymerase chain reaction (PCR), which was performed directly on swabs without enrichment. Using a combination of all methods, we detected GBS in 101 samples. A total of 82 samples (81.2%) were positive using PCR, and 83 samples (82.2%) were confirmed as positive by culture (any method). PCR was more sensitive for detection of GBS than direct culture using any method (P < 0.0005). PCR was also more sensitive than any single enrichment method, but this difference was not statistically significant. With culture as a "gold standard", the PCR method showed a sensitivity of 77.1% and a positive predictive value of 79.3%. Of the culture-positive samples, significantly, more GBSs were detected by direct plating on chromID Strepto B than on selective sheep blood agar (67.5% versus 57% respectively, P < 0.02). After selective enrichment, 92.8% of GBS were isolated on chromID Strepto B compared with 89.2% isolated on sheep blood agar.
Collapse
Affiliation(s)
- Dawn Smith
- Microbiology Department, Freeman Hospital, Newcastle-upon-Tyne NE7 7DN, UK
| | | | | | | | | |
Collapse
|