Rapid intrapartum detection of Group B Streptococci with newer molecular methods

Doctoral Dissertation uoadl:2780704 437 Read counter

Unit:
Τομέας Κλινικοεργαστηριακός
Library of the School of Health Sciences
Deposit date:
2018-08-31
Year:
2018
Author:
Gerolymatos Gerasimos
Dissertation committee:
Κουσκούνη Ευαγγελία, Καθηγήτρια, Ιατρική, ΕΚΠΑ
Κουρκούλη-Καπέτα Ραχήλ, Αν. Καθηγήτρια, Ιατρική, ΕΚΠΑ
Μπάκα Σταυρούλα-Γεωργία, Επ. Καθηγήτρια, Ιατρική, ΕΚΠΑ
Γεννηματά Βασιλική, Αν. Καθηγήτρια, Ιατρική, ΕΚΠΑ
Πανουλής Κωνσταντίνος, Αν. Καθηγητής, Ιατρική, ΕΚΠΑ
Ιακωβίδου Νικολέττα, Αν. Καθηγήτρια, Ιατρική, ΕΚΠΑ
Καπαρός Γεώργιος, Επ. Καθηγητής, Ιατρική, ΕΚΠΑ
Original Title:
Ταχεία ανίχνευση των στρεπτοκόκκων ομάδας Β σε επίτοκες γυναίκες με νεότερες μοριακές τεχνικές
Languages:
Greek
Translated title:
Rapid intrapartum detection of Group B Streptococci with newer molecular methods
Summary:
Introduction: Group B streptococcus (GBS) is an important cause of neonatal infections and one of the leading causes of aggressive infectious disease in neonates. Maternal colonization screening tests combined with administration of chemoprophylaxis have substantially reduced the incidence of Early Onset Disease (EOD) in neonates from GBS. However, although antimicrobial susceptibility of GBS is almost 100%, EOD incidence has reached a plateau which suggests that current screening tests have reached their efficiency limit. The last decade, a series of rapid and accurate diagnostic tests have been developed for the detection of GBS, the use of which as screening methods could eliminate EOD from GBS in neonates.Aim of the study: Aim of the study is to evaluate the prevalence of maternal GBS colonization in each trimester and compare cfbPCR results to the ones from traditional culture.Materials and methods: Vaginal and rectal samples collected from 857 pregnant (205 at 1st trimester, 200 at the 2nd trimester and 452 at the 3rd trimester) and 370 non-pregnant women were examined using traditional culture. Samples collected from the 452 pregnant women between the 35th and 37th week of gestation were also assayed by culture and PCR method targeting the cfb gene. CfbPCR sensitivity, specificity, positive and negative predictive value, were calculated using the culture as the golden standard. Statistical analysis was performed using IBM SPSS 22.0 statistical software package.Results: GBS colonization frequency was calculated at 14,3% for non-pregnant women of reproductive age, 13,7% for pregnant women at the 1st trimester, 16,5% for women at the 2nd trimester, and 18,1% for pregnant women at the 3rd trimester respectively. The measured frequencies are with accordance with large systematic European and International studies. No statistically significant difference in GBS colonization was observed between different ages and gestation trimesters. Rectal samples yielded slightly higher positive rates for the majority of the groups apart from the large group of women pregnant at the 3rd trimester. No statistically significant discrepancy was observed between results from the two sampling methods though. cfbPCR presented high sensitivity and specificity values 100% (95% CI: 95.65% -- 100.00) and 96,74 (95% CI: 94.37% -- 98.30%) respectively and consequently high positive and negative predictive value 87.23% (95% CI: 79,66% -- 92,26%) and 100% (95% CI: 100%-) respectively.Conclusions: Maternal GBS colonization during the last weeks of pregnancy as shown by large systematic European and International studies and confirmed by our results nears frequencies of 1 in 5 pregnant women. Taking in to account that GBS infection is one of the leading causes of neonatal sepsis in developed countries, the need for accurate and rapid screening methods becomes apparent. Our results suggest that cfbPCR is a rapid, highly specific and sensitive GBS colonization detection method. Due to the fact that GBS EOD incidence in neonates is relatively low (0.3 – 1/1000 births), further reduction or elimination of EOD frequencies requires an extremely consistent and accurate screening method. Our conclusion is that cfbPCR appears to exhibit the key attributes to become a worthy alternative or perhaps the next gold standard method for antepartum and intrapartum GBS colonization detection.
Main subject category:
Health Sciences
Keywords:
Streptococcus, PCR
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
138
Number of pages:
164
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