Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay
Abstract Background Streptococcus Group B (GBS) colonization in pregnant women is the most important risk factor for newborn disease due to vertical transmission during delivery. GBS colonization during pregnancy has been implicated as a leading cause of perinatal infections. Traditionally, pregnant...
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| Format: | Article |
| Language: | English |
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BMC
2018-07-01
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| Series: | BMC Infectious Diseases |
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| Online Access: | http://link.springer.com/article/10.1186/s12879-018-3208-4 |
| _version_ | 1819022873744900096 |
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| author | J. A. Carrillo-Ávila J. Gutiérrez-Fernández A. I. González-Espín E. García-Triviño L. G. Giménez-Lirola |
| author_facet | J. A. Carrillo-Ávila J. Gutiérrez-Fernández A. I. González-Espín E. García-Triviño L. G. Giménez-Lirola |
| author_sort | J. A. Carrillo-Ávila |
| collection | DOAJ |
| description | Abstract Background Streptococcus Group B (GBS) colonization in pregnant women is the most important risk factor for newborn disease due to vertical transmission during delivery. GBS colonization during pregnancy has been implicated as a leading cause of perinatal infections. Traditionally, pregnant women are screened for GBS between 35 and 37 weeks of gestation. However, antenatal culture-based screening yields no information on GBS colonization status and offers low predictive value for GBS colonization at delivery. Numerous assays have been evaluated for GBS screening in an attempt to validate a fast and efficient method. The aim of this study was to compare bacteria isolation by culture and two qPCR techniques, targeting sip and cfb genes, respectively, for detecting colonizing GBS. Methods Cultures – the gold-standard technique, a previous qPCR technique targeting the sip gene, and a new proposed qPCR assay targeting the cfb gene were evaluated as diagnostic tools on 320 samples. Results Considering cultures as the gold standard, the evaluated qPCR method detected 75 out of 78 samples, representing a sensitivity of 93.58% (95% confidence interval (CI), 90.89–96.27) and specificity of 94.62% (95% CI, 91.78–97.46). However, an additional analysis was performed for true positives that included not only samples showing positives by culture but samples showing positive for both qPCR assays. The sensitivity and specificity were recalculated including these discrepant samples and a total of 89 samples were considered as positive, giving a prevalence of 27.81%. With this new analysis, the qPCR targeting the cfb gene showed a sensitivity of 95.5% (95% CI, 88.65–98.59) and specificity of 99.13% (95% CI, 96.69–99.97). Conclusions The new qPCR method is a sensitive and specific assay for detecting GBS colonization and represents a valuable tool for identifying candidates for intrapartum antibiotic prophylaxis. Cultures should be retained as the reference and the routine technique because of its specificity and cost analysis ratio, but it would be convenient to introduce PCR techniques to check negative culture samples or when an urgent detection is required to reduce risk of infection among infants. |
| first_indexed | 2024-12-21T04:29:55Z |
| format | Article |
| id | doaj.art-93c8342f33e449a3884c48992ac3b20f |
| institution | Directory Open Access Journal |
| issn | 1471-2334 |
| language | English |
| last_indexed | 2024-12-21T04:29:55Z |
| publishDate | 2018-07-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Infectious Diseases |
| spelling | doaj.art-93c8342f33e449a3884c48992ac3b20f2022-12-21T19:15:58ZengBMCBMC Infectious Diseases1471-23342018-07-011811810.1186/s12879-018-3208-4Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assayJ. A. Carrillo-Ávila0J. Gutiérrez-Fernández1A. I. González-Espín2E. García-Triviño3L. G. Giménez-Lirola4Laboratorio de Microbiología, Universidad de Granada-Instituto de Investigación Biosanitaria de GranadaLaboratorio de Microbiología, Universidad de Granada, Hospital General Virgen de las Nieves- Instituto de Investigación Biosanitaria de GranadaHospital Materno Infantil de JaénHospital Materno Infantil de JaénCollege of Veterinary Medicine, Iowa State UniversityAbstract Background Streptococcus Group B (GBS) colonization in pregnant women is the most important risk factor for newborn disease due to vertical transmission during delivery. GBS colonization during pregnancy has been implicated as a leading cause of perinatal infections. Traditionally, pregnant women are screened for GBS between 35 and 37 weeks of gestation. However, antenatal culture-based screening yields no information on GBS colonization status and offers low predictive value for GBS colonization at delivery. Numerous assays have been evaluated for GBS screening in an attempt to validate a fast and efficient method. The aim of this study was to compare bacteria isolation by culture and two qPCR techniques, targeting sip and cfb genes, respectively, for detecting colonizing GBS. Methods Cultures – the gold-standard technique, a previous qPCR technique targeting the sip gene, and a new proposed qPCR assay targeting the cfb gene were evaluated as diagnostic tools on 320 samples. Results Considering cultures as the gold standard, the evaluated qPCR method detected 75 out of 78 samples, representing a sensitivity of 93.58% (95% confidence interval (CI), 90.89–96.27) and specificity of 94.62% (95% CI, 91.78–97.46). However, an additional analysis was performed for true positives that included not only samples showing positives by culture but samples showing positive for both qPCR assays. The sensitivity and specificity were recalculated including these discrepant samples and a total of 89 samples were considered as positive, giving a prevalence of 27.81%. With this new analysis, the qPCR targeting the cfb gene showed a sensitivity of 95.5% (95% CI, 88.65–98.59) and specificity of 99.13% (95% CI, 96.69–99.97). Conclusions The new qPCR method is a sensitive and specific assay for detecting GBS colonization and represents a valuable tool for identifying candidates for intrapartum antibiotic prophylaxis. Cultures should be retained as the reference and the routine technique because of its specificity and cost analysis ratio, but it would be convenient to introduce PCR techniques to check negative culture samples or when an urgent detection is required to reduce risk of infection among infants.http://link.springer.com/article/10.1186/s12879-018-3208-4Molecular diagnosticPCRGroup B StreptococcusGBS colonizationNeonatal infection |
| spellingShingle | J. A. Carrillo-Ávila J. Gutiérrez-Fernández A. I. González-Espín E. García-Triviño L. G. Giménez-Lirola Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay BMC Infectious Diseases Molecular diagnostic PCR Group B Streptococcus GBS colonization Neonatal infection |
| title | Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay |
| title_full | Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay |
| title_fullStr | Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay |
| title_full_unstemmed | Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay |
| title_short | Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay |
| title_sort | comparison of qpcr and culture methods for group b streptococcus colonization detection in pregnant women evaluation of a new qpcr assay |
| topic | Molecular diagnostic PCR Group B Streptococcus GBS colonization Neonatal infection |
| url | http://link.springer.com/article/10.1186/s12879-018-3208-4 |
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