Diagnostic Performance of Various Methodologies for Group B Streptococcus Screening in Pregnant Woman in China

Husein

Journal of Medical Microbiology

et al. 2022

Introduction. Vaginal colonization of Group B Streptococcus (GBS) is associated with preterm births and neonatal sepsis. Thus routine screening of GBS in prenatal care is recommended. Hypothesis. Chromogenic media (carrot broth) aids in specific and rapid detection of GBS. Aim. To investigate the efficiency of Strep B Carrot Broth for detection of GBS in high vaginal swabs from pregnant women. Methods. In this study 201 vaginal swab samples were collected from pregnant women. Swabs were inoculated in chromogenic media (Strep B Carrot Broth). The positive and negative cultures were inoculated on blood agar and crome agar plates. The colonies were subjected to 16S rRNA sequencing and gene-specific PCR for confirmation. The Christie Atkins Munch Peterson (CAMP) and bile esculin agar (BEA) tests were used for biochemical confirmation. PCR was performed on genomic DNA isolated from uncultured vaginal swabs. Results. It was found that 20/201 (9.9 %) vaginal swab samples were positive in the Strep B Carrot Broth and 17/20 (85 %) and 19/20 (95 %) of these samples yielded colonies on blood agar and crome agar, respectively. Of the 181 carrot broth-negative samples, 1 (0.5 %) and 38 (20.9 %) yielded colonies on blood agar and crome agar plates, respectively. However, 16 s rRNA sequencing revealed that none of the 20 carrot broth-positive cultures were GBS and had sequence similarities to Enterococcus faecalis . This was also confirmed by using gene-specific PCR and BEA positivity. Furthermore, E. faecalis was detected by PCR in DNA isolated from 57 uncultured vaginal swabs samples, GBS could only be detected by PCR in four samples. Conclusion. Carrot broth-based culture can lead to false-positive detection due to the presence of E. faecalis . Thus GBS-positive results in carrot broth must be confirmed by the other molecular and biochemical tests before making a final diagnosis.

Section: Discussionmentioning

confidence: 99%

False-positive detection of Group B Streptococcus (GBS) in chromogenic media (Strep B Carrot Broth) due to presence of Enterococcus faecalis in High Vaginal swabs

Husein

Journal of Medical Microbiology

et al. 2022

Journal of Medical Microbiology

“…LAMP assays, such as the HiberGene assay, are generally less susceptible to inhibition than PCR. The manufacturer's claims include direct testing of clinical swab specimens and culture broth samples without extraction or purification of DNA [6,13]. We did not investigate the inhibition seen with the two S. pyogenes cultures further, but dilution and retesting might have resolved the problem.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the ‘HG Group B Streptococcus’ loop-mediated isothermal amplification assay for accurate identification of Streptococcus agalactiae

Linden

Jaschek

Junker

et al. 2022

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.

“…of Group B Streptococcus in the vagina and the peri-anal regions/rectum is a risk factor for subsequent infection in pregnant women and newbornrns 1 . GBS cultures should be obtained with each pregnancy because colonization may be temporary and it may induce premature delivery 2 .…”

Section: Olonizationmentioning

confidence: 99%

Screening of Group B Streptococcus Agalactiae Among Pregnant Women in Duhok City/ Kurdistan Region/ Iraq

ALI

Saadi

2023

dmj

Background: Pregnant women colonized with Streptococcus agalactiae-Group B Streptococci (GBS) can transmit the bacteria to their new-borns at the time of birth. Intrapartum antibiotic prophylaxis (IAP) can prevent this transmission. The aim of this study is to find out the carriage rate of group B streptococci isolated from pregnant women in Duhok city, Iraq. Other aim is to study the Antibiotic susceptibility patterns of the isolates and to detect the risk factors associated with the growth of these bacteria.Methods: Exactly 821 pregnant women living in Duhok city were randomly screened for GBS colonization, over a period of 7 months from 1st of January, 2022 till 1st of August, 2022. High vaginal swabs (HVS) sample were collected, processed and identification was performed by Vitek system 2. The isolated strains of GBS were selected for in vitro susceptibility testing. As well as also risk factors associated with infection were assessed.Results: GBS was detected in 37/821 accounted (4.51%) pregnant women. Risk factors such as vaginal discharge, UTI, Diabetes, abortions and still birth did not show major differences between positive and negative cases of GBS. Pencillin G, Co-Amoxiclav, Nitrofurantoin, Vancomycin and Ampiciilin have shown the highest sensitivity percentages (93.9%, 93.8%, 88.9%, 87.5% and 84% respectively). The sensitivity rate for other B-Lactams: Cepholothin, Ceftriaxone and Cefixim were: 70.6%, 63% and 78% respectively. The sensitivity for Gentamicin was 38.9% and 48.4% for Ciprofloxacin. However, the lowest sensitivity rates were detected for Clindamycin, Amikacin and Erythromycin: 26.1%, 30% and 30.5% respectively. Conclusions:Carriage rates of GBS among pregnant women in this setting are still lowgrade. Penicillin and Ampicillin are the drugs of choice (intra-partum prophylaxis) against GBS in pregnancy. Co-amoxiclave and Vancomycin also had a high level of sensitivity.