Group B Streptococcus in Pregnancy

Review of Low-Cost Interventions for Reducing Neonatal Mortality and Morbidity in Low- and Middle-Income Countries

AIM

This review examines low-cost interventions for reducing neonatal mortality and morbidity in low- and middle-income countries (LMICs).

METHODS

A systematic PubMed search and neonatal care data from World Health Organization (2014-2024) were used to revise interventions including prenatal care, early essential newborn care (EENC), resuscitation and therapeutic hypothermia, Kangaroo mother care (KMC), respiratory support, breastfeeding, sepsis prevention, safe neonatal transfer, neonatal network in LMICs and suggestions for improvement. Out of 9295 initially identified articles, 252 studies were selected as relevant to the research objectives.

RESULTS

In LMICs, the use of antenatal corticosteroids and magnesium sulfate remains limited in routine obstetric practice. Although EENC, KMC and early breastfeeding significantly reduce neonatal mortality, these interventions are under-prioritised and insufficiently implemented. Neonatal resuscitation and respiratory support are constrained by inadequate equipment and a shortage of trained healthcare personnel. Healthcare-associated sepsis, compounded by antibiotic resistance, continues to strain neonatal intensive care units. Additionally, unsafe neonatal transfers and poor coordination among different levels of neonatal care highlight the need for better integration within regional health systems.

CONCLUSIONS

To reduce neonatal mortality and enhance care in LMICs, systematic training, effective implementation and the sustainable delivery of proven, low-cost, high-impact interventions are urgently needed.

PCR targeting 16S rRNA, cfb, and hylB for group B Streptococcus detection in women with 35 to 37 weeks of pregnancy

AIMS

Polymerase chain reaction (PCR) is a rapid molecular technique for pathogen detection, but its application in detecting group B Streptococcus (GBS) requires further exploration. This study assessed the diagnostic performance of the PCR method for GBS detection in pregnant women with 35 to 37 weeks of pregnancy.

METHODS

This study enrolled 116 women at 35-37 weeks of pregnancy and simultaneously collected two vaginal swab samples for GBS detection via culture and PCR methods.

RESULTS

Through the culture method, 21 (18.1%) samples were positive for GBS. Moreover, 24 (20.7%), 23 (19.8%), and 23 (19.8%) samples were positive for GBS according to PCR methods targeting 16S rRNA, cfb, and hylB, respectively. The results of PCR-based GBS detection of 16S rRNA (Kappa value = 0.917, p < 0.01), cfb (Kappa value = 0.944, p < 0.01), and hylB (Kappa value = 0.944, p < 0.01) were consistent with those of the culture method. The sensitivity and specificity were 1.000 and 0.968 for the PCR method targeting 16S rRNA, 1.000 and 0.979 for cfb, and 1.000 and 0.979 for hylB, respectively.

CONCLUSION

PCR targeting 16S rRNA, cfb, and hylB may serve as a reliable diagnostic method for GBS detection in women with 35 to 37 weeks of pregnancy.

Association between maternal rectovaginal group B streptococcus and the risk of stillbirth: a meta-analysis

Background

Group B streptococcus (GBS) colonization in pregnant women is associated with adverse perinatal outcomes, including stillbirth. This meta-analysis investigated the relationship between maternal rectovaginal GBS colonization and the risk of stillbirth.

Methods

We conducted a comprehensive literature search across several databases, including PubMed, Embase, Web of Science, Wanfang, and China National Knowledge Infrastructure, covering studies published from the inception of the database until September 9, 2024. The search focused on observational studies comparing the risk of stillbirth in pregnant women with and without rectovaginal GBS colonization. Results were summarized using odds ratios (ORs) and 95% confidence intervals (CIs), and a random-effects model was used to account for potential heterogeneity.

Results

A total of ten studies comprising 121,195 pregnant women were included in the analysis. The pooled results indicated no significant overall association between maternal rectovaginal GBS colonization and the risk of stillbirth (OR: 1.66, 95% CI [0.95-2.91], p = 0.08; I2 = 84%). However, sensitivity analyses revealed a significant association in studies that included intrapartum antibiotic prophylaxis (IAP) (OR: 1.36, 95% CI [1.02-1.80], p = 0.03). Subgroup analyses demonstrated a significant association between maternal rectovaginal GBS colonization and stillbirth risk in retrospective studies (OR: 2.62, p = 0.04) and in studies employing multivariate analysis (OR: 2.11, p = 0.04).

Conclusions

While the meta-analysis did not find a significant overall association between maternal rectovaginal GBS colonization and stillbirth, significant associations were noted under specific conditions, such as studies using IAP, retrospective designs, and multivariate analyses. Further research is needed to clarify these associations.

Maternal and infant microbiome and birth anthropometry

Preterm birth is the leading cause of neonatal mortality and morbidity. Microbiome dysbiosis in the mother and infant may contribute to their adverse outcomes. 16S rRNA amplicon sequencing was performed on all samples. Phyloseq, microbiomeSeq, and NetCoMi were utilized for bioinformatics analysis. Statistical tests included the Wilcoxon test, ANOVA, permutational multivariate analysis of variance (PERMANOVA), and linear regression. Statistical significance was set at p value <0.05. The establishment of an infant's microbiome most likely begins in utero and is influenced by the maternal microbiome. Infants' samples were enriched with Salmonella. There is a complex interplay among the microbial taxa noticeable at birth, exhibiting variability in interaction within the same host and across different hosts. Both maternal and infant microbiomes influence the anthropometric measures determined at birth, and a sex-based difference in correlation exists. This study highlights the potential role of maternal and infant microbiomes in improving pregnancy and neonatal outcomes.

A Controlled, Retrospective, Single-Center Study to Evaluate the Role of a Probiotic Mixture Administered during Pregnancy in Reducing Streptococcus Agalactiae Swab Positivity and the Frequency of Premature Rupture of Amniochorionic Membranes

Intrapartum antibiotic prophylaxis, considered able to prevent streptococcal transmission from mother to newborn and its severe negative consequences, leads to microbiota dysbiosis, described as having a negative impact on well-being in both elements of the dyad. Enterococcus faecium L3 is a probiotic strain capable of exerting strong antagonistic activity against most streptococci, including S. agalactiae, due to the production of bacteriocins (known as enterocins A and B). A proprietary probiotic mixture containing the strain L3 demonstrated, in 2016, a significant reduction in episodes of PROM in pregnant women, with a less-than-expected effect on the vaginal-rectal presence of the pathogen S. agalactiae. With the aim of confirming the role exerted by the probiotic mixture in PROM episodes and to better understand the value of its impact on the clinical detection of S. agalactiae, we have retrospectively analyzed the results obtained in 125 L3-treated (over 12 weeks) women versus 125 untreated controls. Despite some limitations, our analysis has confirmed the role exerted by the probiotic in significantly reducing the following: (1) episodes of PROM, (2) vaginal-rectal positivity for S. agalactiae, and (3) the need to administer intrapartum antibiotics for prophylaxis. It likely also suggests operating using a cultural method very specific to S. agalactiae when testing women who were administered an Enterococcus-based probiotic.

Loratadine Derivative Lo-7: A Weapon against Drug-Resistant Enterococcus and Streptococcal Infections

The primary obstacles in the management of Enterococcus and Streptococcal infections are drug resistance and biofilm formation. Our study revealed that loratadine at a concentration of ≥25 μM exhibited significant inhibitory effects on biofilm formation in 167 clinical strains of Enterococcus faecalis and 15 clinical isolates of Streptococcus agalactiae, Streptococcus pyogenes, and Streptococcus pneumoniae. Additionally, the antibiofilm activity against E. faecalis and Streptococcal was demonstrated by several loratadine derivatives with altered side-chain carbamate moieties. This study investigated the antibacterial activity of the loratadine derivative Lo-7 against clinical strains of S. agalactiae and S. pyogenes, with minimum inhibitory concentrations ranging from 12.5 to 25 μM. The findings revealed that a low concentration of loratadine derivative Lo-7 (3.125 μM) significantly augmented the bactericidal efficacy of vancomycin against multidrug-resistant (MDR) S. agalactiae, both in vitro and in vivo. The loratadine derivative Lo-7, even at low concentrations, demonstrated significant efficacy in eliminating intracellular MDR S. agalactiae within macrophages, potentially indicating a unique advantage over vancomycin, linezolid, and loratadine. Mechanistically, exposure to the loratadine derivative Lo-7 resulted in membrane depolarization without affecting membrane permeability in S. agalactiae. The potential targeting of the SecG subunit of the SecYEG membrane-embedded channel by the loratadine derivative Lo-7 in S. agalactiae was identified through quantitative proteomics, a drug affinity responsive target stability assay, and molecular docking.

Current research update on group B streptococcal infection related to obstetrics and gynecology

Group B streptococcal (GBS) is a Gram-positive bacterium that is commonly found in the gastrointestinal tract and urogenital tract. GBS infestation during pregnancy is a significant contributor to maternal and neonatal morbidity and mortality globally. This article aims to discuss the infectious diseases caused by GBS in the field of obstetrics and gynecology, as well as the challenges associated with the detection, treatment, and prevention of GBS.

An opportunistic pathogen under stress: how Group B Streptococcus responds to cytotoxic reactive species and conditions of metal ion imbalance to survive

Group B Streptococcus (GBS; also known as Streptococcus agalactiae) is an opportunistic bacterial pathogen that causes sepsis, meningitis, pneumonia, and skin and soft tissue infections in neonates and healthy or immunocompromised adults. GBS is well-adapted to survive in humans due to a plethora of virulence mechanisms that afford responses to support bacterial survival in dynamic host environments. These mechanisms and responses include counteraction of cell death from exposure to excess metal ions that can cause mismetallation and cytotoxicity, and strategies to combat molecules such as reactive oxygen and nitrogen species that are generated as part of innate host defence. Cytotoxicity from reactive molecules can stem from damage to proteins, DNA, and membrane lipids, potentially leading to bacterial cell death inside phagocytic cells or within extracellular spaces within the host. Deciphering the ways in which GBS responds to the stress of cytotoxic reactive molecules within the host will benefit the development of novel therapeutic and preventative strategies to manage the burden of GBS disease. This review summarizes knowledge of GBS carriage in humans and the mechanisms used by the bacteria to circumvent killing by these important elements of host immune defence: oxidative stress, nitrosative stress, and stress from metal ion intoxication/mismetallation.

Intrapartum antibiotic prophylaxis selects for mutators in group B streptococci among persistently colonized patients

Through vaginal colonization, GBS causes severe pregnancy outcomes including neonatal sepsis and meningitis. Although intrapartum antibiotic prophylaxis (IAP) has reduced early-onset disease rates, persistent GBS colonization has been observed in patients following prophylaxis. To determine whether IAP selects for genomic signatures that enhance GBS survival and persistence in the vaginal tract, whole-genome sequencing was performed on 97 isolates from 58 patients before (prenatal) and after (postpartum) IAP/childbirth. Core-gene mutation analysis identified 7,025 mutations between the paired isolates. Three postpartum isolates accounted for 98% of mutations and were classified as "mutators" because of point mutations within DNA repair systems. In vitro assays revealed stronger biofilms in two mutators. These findings suggest that antibiotics select for mutations that promote survival in vivo, which increases the likelihood of transmission to neonates. They also demonstrate how mutators can provide a reservoir of beneficial mutations that enhance fitness and genetic diversity in the GBS population.

Factors Affecting Awareness of Pregnancy Screening for Group B Streptococcus Infection Among Women of Reproductive Age in Jazan Province, Saudi Arabia

Background

Group B streptococcus (GBS) infection is one of the leading causes of neonatal sepsis and meningitis. GBS screening and intrapartum antibiotic prophylaxis can effectively prevent early-onset GBS disease. This study aimed to assess the awareness of the risks of GBS infection and screening in Jazan Province, Saudi Arabia.

Methodology

A cross-sectional study was conducted using a survey of 995 women aged 18-45 in Jazan, Saudi Arabia. Data were collected between January to April 2023 and included information on sociodemographic characteristics, awareness of GBS infection, and perspectives on GBS screening.

Results

The response rate was 97.45%, and the mean age of the participants was 31.50 ± 9.80 years. Most were married (60.2%), had a university education (81.11%), and 59% were pregnant or had a pregnancy history. Only 23% had heard of GBS, associated with age, marital status, job, pregnancy status, awareness of GBS risk factors, and pregnancy follow-up (p < 0.05). Women most aware were students (55.9%), married (55.46%), pregnant or had a pregnancy history (51.09%), knew risk factors of GBS (38.86%), and were followed by a specialist (88.14%). Regarding GBS screening preferences, 40% preferred universal screening without consent, 31% with consent, 16% for high-risk pregnancies with consent, and 13% for high-risk pregnancies without consent.

Conclusion

The study found low awareness of GBS among women residing in Jazan, Saudi Arabia. Factors related to demographic details and obstetric follow-up were associated with better understanding. Most women preferred universal screening for GBS, with or without consent. Effective health education is needed to raise women's awareness of screening benefits and risks. This education can help women make informed decisions and improve prevention and care. Future studies may evaluate healthcare providers' awareness of GBS.