Maternal Colonization With Group B Streptococcus and Serotype Distribution Worldwide: Systematic Review and Meta-analyses

Immune responses against group B Streptococcus monovalent and pentavalent capsular polysaccharide tetanus toxoid conjugate vaccines in Balb/c mice

Immunization of pregnant women with Group B Streptococcus (GBS) capsular polysaccharide (CPS) conjugate vaccine (CV) could protect young infants against invasive GBS disease. We evaluated the immunogenicity of investigational five GBS monovalent (serotypes Ia, Ib, II, III, and V) CPS-tetanus toxoid (TT)-CV with adjuvant and GBS pentavalent CPS-TT-CV with adjuvant (GBS5-CV-adj) and without adjuvant (GBS5-CV-no-adj), in Balb/c mice. Aluminum phosphate was the adjuvant in the formulations, where included. The homotypic immunoglobulin G (IgG) geometric mean concentration (GMC) and opsonophagocytic activity (OPA) geometric mean titer (GMT) did not differ after the third dose of the GBS5-CV-adj vaccine compared with the monovalent counterparts for all five serotypes. The GBS5-CV-adj induced higher post-vaccination serotype-specific IgG GMCs and OPA GMTs compared to GBS5-CV-no_adj. The GBS5-CV with and without adjuvant should be considered for further development as a potential vaccine for pregnant women to protect their infants against invasive GBS disease.

Determinants of Gastrointestinal Group B Streptococcus Carriage in Adults

Background

Streptococcus agalactiae (Group B Streptococcus, GBS) is a commensal Gram-positive bacterium found in the human gastrointestinal and urogenital tracts. Much of what is known about GBS relates to the diseases it causes in pregnant people and neonates. However, GBS is a common cause of disease in the general population with 90% of GBS mortality occurring in non-pregnant people. There are limited data about the predisposing factors for GBS and the reservoirs in the body. To gain an understanding of the determinants of gastrointestinal GBS carriage, we used stool samples and associated metadata to determine the prevalence and abundance of GBS in the gut microbiome of adults and find risk factors for GBS status.

Methods

We used 754 stool samples collected from adults in Wisconsin from 2016-2017 to test for the prevalence and abundance of GBS using a Taqman probe-based qPCR assay targeting two GBS-specific genes: cfp and sip. We compared the microbiome compositions of the stool samples by GBS status using 16S rRNA analysis. We compared associations with GBS status and 557 survey variables collected during sample acquisition (demographics, diet, overall health, and reproductive health) using univariate and multivariate analyses.

Results

We found 137/754 (18%) of participants had detectable GBS in their stool samples with a median abundance of 104 copies per nanogram of starting DNA. There was no difference in GBS status or abundance based on gender. Beta-diversity, Bray-Curtis and Unweighted UniFrac, was significantly different based on carrier status of the participant. Prior to p-value correction, 59/557 (10.6%) survey variables were significantly associated with GBS carrier status and 11/547 (2.0%) variables were significantly associated with abundance (p-value<0.05). After p-value correction, 2/547 (0.4%) variables were associated with GBS abundance: an increased abundance of GBS was associated with a decreased frequency since last dental checkup (p<0.001) and last dental cleaning (p<0.001). Increased GBS abundance was significantly associated with increased frequency of iron consumption (p=0.007) after p-value correction in multivariate models.

Conclusions

GBS is found in stool samples from adults in Wisconsin at similar frequencies as pregnant individuals screened with rectovaginal swabs. We did not find associations between risk factors historically associated with GBS in pregnant people, suggesting that risk factors for GBS carriage in pregnancy may differ from those in the general population. We found that frequency of iron consumption and dental hygiene are risk factors for GBS carriage in Wisconsin adults. Given that these variables were not assayed in previous GBS surveys, it is possible they also influence carriage in pregnant people. Taken together, this work serves as a foundation for future work in developing approaches to decrease GBS abundance in carriers.

Group B Streptococcus CRISPR1 Typing of Maternal, Fetal, and Neonatal Infectious Disease Isolates Highlights the Importance of CC1 in In Utero Fetal Death

We performed a descriptive analysis of group B Streptococcus (GBS) isolates responsible for maternal and fetal infectious diseases from 2004 to 2020 at the University Hospital of Tours, France. This represents 115 isolates, including 35 isolates responsible for early-onset disease (EOD), 48 isolates responsible for late-onset disease (LOD), and 32 isolates from maternal infections. Among the 32 isolates associated with maternal infection, 9 were isolated in the context of chorioamnionitis associated with in utero fetal death. Analysis of neonatal infection distribution over time highlighted the decrease in EOD since the early 2000s, while LOD incidence has remained relatively stable. All GBS isolates were analyzed by sequencing their CRISPR1 locus, which is an efficient way to determine the phylogenetic affiliation of strains, as it correlates with the lineages defined by multilocus sequence typing (MLST). Thus, the CRISPR1 typing method allowed us to assign a clonal complex (CC) to all isolates; among these isolates, CC17 was predominant (60/115, 52%), and the other main CCs, such as CC1 (19/115, 17%), CC10 (9/115, 8%), CC19 (8/115, 7%), and CC23 (15/115, 13%), were also identified. As expected, CC17 isolates (39/48, 81.3%) represented the majority of LOD isolates. Unexpectedly, we found mainly CC1 isolates (6/9) and no CC17 isolates that were responsible for in utero fetal death. Such a result highlights the possibility of a particular role of this CC in in utero infection, and further investigations should be conducted on a larger group of GBS isolated in a context of in utero fetal death. IMPORTANCE Group B Streptococcus is the leading bacterium responsible for maternal and neonatal infections worldwide, also involved in preterm birth, stillbirth, and fetal death. In this study, we determined the clonal complex of all GBS isolates responsible for neonatal diseases (early- and late-onset diseases) and maternal invasive infections, including chorioamnionitis associated with in utero fetal death. All GBS was isolated at the University Hospital of Tours from 2004 to 2020. We described the local group B Streptococcus epidemiology, which confirmed national and international data concerning neonatal disease incidence and clonal complex distribution. Indeed, neonatal diseases are mainly characterized by CC17 isolates, especially in late-onset disease. Interestingly, we identified mainly CC1 isolates responsible for in utero fetal death. CC1 could have a particular role in this context, and such a result should be confirmed on a larger group of GBS isolated from in utero fetal death.

Changes in the Prevalence of Infection in Pregnant Women during the COVID-19 Lockdown

BACKGROUND

During the outbreak of SARS-CoV-2, strict mitigation measures and national lockdowns were implemented. Our objective was to investigate to what extent the prevalence of some infections in pregnancy was altered during different periods of the COVID-19 pandemic.

METHODS

This was a single centre retrospective cohort study conducted in the Netherlands on data collected from electronic patient files of pregnant women from January 2017 to February 2021. We identified three time periods with different strictness of mitigation measures: the first and second lockdown were relatively strict; the inter-lockdown period was less strict. The prevalence of the different infections (Group B Streptococcus (GBS)-carriage, urinary tract infections and Cytomegalovirus infection) during the lockdown was compared to the same time periods in previous years (2017-2019).

RESULTS

In the first lockdown, there was a significant decrease in GBS-carriage (19.5% in 2017-2019 vs. 9.1% in 2020; p = 0.02). In the period following the first lockdown and during the second, no differences in prevalence were found. There was a trend towards an increase in positive Cytomegalovirus IgM during the inter-lockdown period (4.9% in 2017-2019 vs. 12.8% in 2020; p = 0.09), but this did not reach statistical significance. The number of positive urine cultures did not significantly change during the study period.

CONCLUSIONS

During the first lockdown there was a reduction in GBS-carriage; further studies are warranted to look into the reason why.

Epidemiology of co-infections in pregnant women living with human immunodeficiency virus 1 in rural Gabon: a cross-sectional study

BACKGROUND

There is no recent epidemiological data on HIV infection in Gabon, particularly in pregnant women. To close this gap, an HIV-prevalence survey was conducted among Gabonese pregnant women, followed by a cross-sectional case-control study in which the prevalence of various co-infections was compared between HIV-positive and HIV-negative pregnant women.

METHODS

Between 2018 and 2019, data for the HIV-prevalence survey were collected retrospectively in 21 Gabonese antenatal care centres (ANCs). Subsequently, for the prospective co-infection study, all HIV-positive pregnant women were recruited who frequented the ANC in Lambaréné and a comparator sub-sample of HIV-negative pregnant women was recruited; these activities were performed from February 2019 to February 2020. The mean number of co-infections was ascertained and compared between HIV-positive and HIV-negative women. Additionally, the odds for being co-infected with at least one co-infection was evaluated and compared between HIV-positive and HIV-negative women.

RESULTS

HIV-positivity was 3.9% (646/16,417) among pregnant women. 183 pregnant women were recruited in the co-infection study. 63% of HIV-positive and 75% of HIV-negative pregnant women had at least one co-infection. There was a trend indicating that HIV-negative women were more often co-infected with sexually transmitted infections (STIs) than HIV-positive women [mean (standard deviation, SD): 2.59 (1.04) vs 2.16 (1.35), respectively; P = 0.056]; this was not the case for vector-borne infections [mean (SD): 0.47 (0.72) vs 0.43 (0.63), respectively; P = 0.59].

CONCLUSIONS

Counterintuitively, the crude odds for concomitant STIs was lower in HIV-positive than in HIV-negative women. The change of magnitude from the crude to adjusted OR is indicative for a differential sexual risk factor profile among HIV-positive and HIV-negative women in this population. This might potentially be explained by the availability of sexual health care counselling for HIV-positive women within the framework of the national HIV control programme, while no such similar overall service exists for HIV-negative women. This highlights the importance of easy access to sexual healthcare education programmes for all pregnant women irrespective of HIV status.

Prevalence, Antimicrobial Susceptibility Pattern and Associated Factors of Group B Streptococcus Among Pregnant Women Attending Antenatal Care at Bule Hora University Teaching Hospital, Southern Ethiopia

Background

In many parts of the world, Group B Streptococcus (GBS) is a major cause of maternal and neonatal illness and mortality. It has a negative impact on neonatal and pregnancy outcomes. A worrisome problem in Ethiopia is the unknown rate of antibiotic resistance and the risk factors connected to GBS infections.

Objective

This study was to determine the prevalence, antibiotic susceptibility pattern, and related variables of Group B Streptococcus among pregnant women receiving prenatal treatment conducted at Bule Hora University Teaching Hospital, Southern Ethiopia, between June 1 and August 30, 2022.

Methods

An institutional-based cross-sectional study was conducted among 213 pregnant women attending antenatal care at Bule Hora University Teaching Hospital. Data on sociodemographic and related factors were gathered using structured questionnaires. The study's participants were selected using the consecutive sampling method. The lower vaginal/rectum area was brushed with a sterile cotton swab to capture the vaginal/rectum swab sample, which was then examined using microbiological techniques. The Kirby-Bauer disc diffusion method was used to assess antibiotic susceptibility in GBS isolates. Logistic regression analysis was performed on the data using SPSS version 26. It was deemed statistically significant when the p-value was 0.05 with a 95% confidence interval (CI).

Results

The overall prevalence of GBS was 16.9% (CI: 0.12-0.23). A history of prematurity of the membrane (AOR: 3.35, 95% CI: 1.19-9.45), a history of stillbirth (AOR: 2.88, 95% CI: 1.07-7.71), and preterm delivery history (AOR: 3.41, 95% CI: 1.31-8.89) (p 0.05) were independent predictors of GBS infection. Cefepime had the highest resistance at 58.3%. Most GBS isolates showed high susceptibility to vancomycin (97.2%) and ampicillin (91.7%). Multidrug resistance was 13.9%.

Conclusion

The prevalence of GBS was considerably high among pregnant women in this study. This finding emphasises the need for routine screening and testing of antimicrobial susceptibility to provide antibiotic prophylaxis and minimise newborn infection and comorbidity.

Early-onset group B streptococcal disease in African countries and maternal vaccination strategies

Invasive group B streptococcal (GBS) disease is the commonest perinatally-acquired bacterial infection in newborns; the burden is higher in African countries where intrapartum antibiotic prophylaxis strategies are not feasible. In sub-Saharan Africa, almost one in four newborns with GBS early-onset disease will demise, and one in ten survivors have moderate or severe neurodevelopmental impairment. A maternal GBS vaccine to prevent invasive GBS disease in infancy is a pragmatic and cost-effective preventative strategy for Africa. Hexavalent polysaccharide protein conjugate and Alpha family surface protein vaccines are undergoing phase II clinical trials. Vaccine licensure may be facilitated by demonstrating safety and immunological correlates/thresholds suggestive of protection against invasive GBS disease. This will then be followed by phase IV effectiveness studies to assess the burden of GBS vaccine preventable disease, including the effect on all-cause neonatal infections, neonatal deaths and stillbirths.

Group B Streptococcus infection-induced ovarian vein thrombosis identified during cesarean section: A case report and a literature review

RATIONALE

Ovarian vein thrombosis (OVT) is a rare yet potentially life-threatening condition associated with thromboembolic events. Group B Streptococcus (GBS) is a type of β-hemolytic Gram-positive bacterium known for asymptomatic colonization in the lower genital and gastrointestinal tracts. Here we reported a 35-year-old multiparous woman with gestational diabetes who suffered from placental abruption, stillbirth, OVT, septic shock, and renal failure due to severe GBS infection.

PATIENT CONCERNS

A 35-year-old woman with gestational diabetes presented with acute and sustained lower abdominal cramping, vaginal bleeding, and fever at 35 gestational weeks.

DIAGNOSES

Based on preoperative ultrasound and intraoperative findings, the patient was diagnosed with placental abruption, intrauterine fetal demise, and right OVT. GBS was cultured from the amniotic fluid obtained during cesarean section.

INTERVENTIONS

The patient underwent a right adnexectomy during a cesarean section and received intravenous antibiotics. Subsequently, an ultrasound-guided uterine curettage was performed due to recurrent fever.

OUTCOMES

After a prolonged course of intravenous antibiotics for over a month, the patient recovered and was discharged from the hospital.

LESSONS

This case underscores the need for early initiation of anticoagulant protocols in cases of OVT, particularly when GBS infection is identified as a predisposing factor. Further research and awareness are warranted to better understand the relationship between GBS infection and OVT and to optimize management strategies in such cases.

Long-term surveillance of group B Streptococcus strains isolated from infection and colonization in pregnant women and newborns

Introduction. Group B Streptococcus (GBS) remains the leading cause of bacterial neonatal infections worldwide, despite the spread of recommendations on vaginal screening and antibiotic prophylaxis.Hypothesis/Gap Statement. There is a need to evaluate the potential changes in GBS epidemiology over time following the introduction of such guidelines.Aim. Our aim was to perform a descriptive analysis of the epidemiological characteristics of GBS by conducting a long-term surveillance of strains isolated between 2000 and 2018, using molecular typing methods.Methodology. A total of 121 invasive strains, responsible for maternal infections (20 strains), fetal infections (8 strains) and neonatal infections (93 strains), were included in the study, representing all the invasive isolates during the period; in addition, 384 colonization strains isolated from vaginal or newborn samples were randomly selected. The 505 strains were characterized by capsular polysaccharide (CPS) type multiplex PCR assay and the clonal complex (CC) was assigned using a single nucleotide polymorphism PCR assay. Antibiotic susceptibility was also determined.Results. CPS types III (32.1 % of the strains), Ia (24.6 %) and V (19 %) were the most prevalent. The five main CCs observed were CC1 (26.3 % of the strains), CC17 (22.2 %), CC19 (16.2 %), CC23 (15.8 %) and CC10 (13.9 %). Neonatal invasive GBS diseases were predominantly due to CC17 isolates (46.3 % of the strains), which mainly express CPS type III (87.5 %), with a very high prevalence in late-onset diseases (76.2 %).Conclusion. Between 2000 and 2018, we observed a decrease in the proportion of CC1 strains, which mainly express CPS type V, and an increase in the proportion of CC23 strains, mainly expressing CPS type Ia. Conversely, there was no significant change in the proportion of strains resistant to macrolides, lincosamides or tetracyclines. The two molecular techniques used in our study provide almost as much information as classical serotyping and multilocus sequence typing, but are quicker, easy to perform, and avoid long sequencing and analysis steps.

Analysis of molecular characteristics of CAMP-negative Streptococcus agalactiae strains

Background

Streptococcus agalactiae can produce CAMP factor, which can promote the β-hemolysin activity of Staphylococcus aureus, forming an arrow-shaped hemolysis enhancement zone at the intersection of the two bacterial species on a blood agar plate. This characteristic feature of Streptococcus agalactiae has led to the widespread use of the CAMP test as an identification method.

Methods

Vaginal/rectal swabs, collected from women at 35-37  weeks of pregnancy, were first inoculated into a selective enrichment broth media, then subcultured onto GBS chromogenic agar and 5% sheep blood agar sequentially. The VITEK-2 automatic identification system and MALDI-TOF MS were initially employed for identification, followed by the CAMP test. CAMP-negative strains underwent 16S rDNA and cfb gene sequence analysis, as well as bacterial multilocus sequence typing.

Results

A total of 190 strains were isolated, with 15 identified as CAMP-negative. Further 16S rDNA gene sequence analysis confirmed that all 15 strains were Streptococcus agalactiae. The MLST typing assay revealed that these 15 strains were of the ST862 type. The cfb gene was amplified and electrophoresed, but no specific fragments were found, indicating that these strains lack the CAMP factor due to cfb gene deletion. Antibiotic susceptibility tests demonstrated no resistance to penicillin, ampicillin, vancomycin and linezolid among the GBS strains. However, there are significant differences in resistance rates to tetracycline.

Conclusion

This study found that 7.9% of GBS strains isolated from the vagina/rectum of pregnant women were CAMP-negative, suggesting that the CAMP test method or primers targeting the cfb gene should not be used as the sole presumptive test for GBS identification.

Calibration of a serum reference standard for Group B streptococcal polysaccharide conjugate vaccine development using surface plasmon resonance

Group B streptococcus (GBS) is a leading cause of neonatal morbidity and mortality worldwide. Development of a maternal vaccine to protect newborns through placentally transferred antibody is considered feasible based on the well-established relationship between anti-GBS capsular polysaccharide (CPS) IgG levels at birth and reduced risk of neonatal invasive GBS. An accurately calibrated serum reference standard that can be used to measure anti-CPS concentrations is critical for estimation of protective antibody levels across serotypes and potential vaccine performance. For this, precise weight-based measurement of anti-CPS IgG in sera is required. Here, we report an improved approach for determining serum anti-CPS IgG levels using surface plasmon resonance with monoclonal antibody standards, coupled with a direct Luminex-based immunoassay. This technique was used to quantify serotype-specific anti-CPS IgG levels in a human serum reference pool derived from subjects immunized with an investigational six-valent GBS glycoconjugate vaccine.

Population genetics of group B Streptococcus from maternal carriage in an ethnically diverse community in London

Introduction

Maternal immunization against Group B Streptococcus (GBS) has the potential to significantly reduce the burden of neonatal GBS infections. Population genetics of GBS from maternal carriage can offer key insights into vaccine target distribution.

Methods

In this study we characterized the population structure of GBS isolates from maternal carriage (n = 535) in an ethnically diverse community in London, using whole genome sequencing.

Results

The isolates clustered into nine clonal complexes (CCs) but the majority (95%) belonged to five lineages: CC1 (26%), CC19 (26%), CC23 (20%), CC17 (13%) and CC8/10 (10%). Nine serotypes were identified, the most common were serotypes III (26%), V (21%), II (19%) and Ia (19%). Other serotypes (Ib, IV, VI, VII, IX) represented less than 10% of all isolates each. Intra-lineage serotype diversity was observed in all major CCs but was highest in CC1, which revealed nine serotypes. Nearly all isolates (99%) carried at least one of the four alpha family protein genes (alpha, alp1, alp23, and rib). All isolates were susceptible to penicillin. We found 21% and 13% of isolates to be resistant to clarithromycin and clindamycin, respectively. Prevalence of macrolide-lincosamide-streptogramin B (MLS_B) resistance genes was 22% and they were most common in CC19 (37%) and CC1 (28%), and isolates with serotypes V (38%) and IV (32%). We identified some associations between maternal ethnicity and GBS population structure. Serotype Ib was significantly less common among the South Asian compared to Black women (S. Asian: 3/142, Black: 15/135, p = 0.03). There was also a significantly lower proportion of CC1 isolates among the White other (24/142) in comparison to Black (43/135) and S. Asian (44/142) women (p = 0.04). We found a significantly higher proportion of CC17 isolates among the White other compared to S. Asian women (White other: 32/142, S. Asian: 10/142, p = 0.004).

Conclusion

Our study showed high prevalence of GBS vaccine targets among isolates from pregnant women in London. However, the observed serotype diversity in CC1 and high prevalence of MLS_B resistance genes in CC19 demonstrates presence of high risk lineages, which might act as a reservoir of non-vaccine strains and antimicrobial resistance determinants.

Group B Streptococcus and the risk of perinatal morbidity and mortality following term labor

Streptococcus agalactiae (group B Streptococcus) colonizes the genital tract of approximately 20% of pregnant women. In the absence of intervention, approximately 1% of infants born to colonized mothers exhibit a clinical infection. This has led to implementation of screening and intervention in the form of intrapartum antibiotic prophylaxis in many countries, including the United States. However, screening has not been introduced in a substantial minority of other countries because of the absence of supportive level 1 evidence, the very large number needed to treat to prevent 1 case, and concerns about antimicrobial resistance. Optimal screening would involve rapid turnaround (to facilitate intrapartum testing) and report antibiotic sensitivity, but no such method exists. There is significant scope for a personalized medicine approach, targeting intrapartum antibiotic prophylaxis to cases at greatest risk, but the pathogen and host factors determining the risk of invasive disease are incompletely understood. Epidemiologic data have indicated the potential of prelabor invasion of the uterus by group B Streptococcus, and metagenomic analysis revealed the presence of group B Streptococcus in the placenta in approximately 5% of pregnant women at term before onset of labor and membrane rupture. However, the determinants and consequences of prelabor invasion of the uterus by group B Streptococcus remain to be established. The vast majority (98%) of invasive neonatal disease is caused by 6 serotypes, and hexavalent vaccines against these serotypes have completed phase 2 trials. However, an obstacle to phase 3 studies is conducting an adequately powered trial to demonstrate clinical effectiveness given that early-onset disease affects approximately 1 in 1000 births in the absence of vaccination.

Interspecies Interactions within the Host: the Social Network of Group B Streptococcus

Group B Streptococcus (GBS) is a pervasive neonatal pathogen accounting for a combined half a million deaths and stillbirths annually. The most common source of fetal or neonatal GBS exposure is the maternal microbiota. GBS asymptomatically colonizes the gastrointestinal and vaginal mucosa of 1 in 5 individuals globally, although its precise role in these niches is not well understood. To prevent vertical transmission, broad-spectrum antibiotics are administered to GBS-positive mothers during labor in many countries. Although antibiotics have significantly reduced GBS early-onset neonatal disease, there are several unintended consequences, including an altered neonatal microbiota and increased risk for other microbial infections. Additionally, the incidence of late-onset GBS neonatal disease remains unaffected and has sparked an emerging hypothesis that GBS-microbe interactions in developing neonatal gut microbiota may be directly involved in this disease process. This review summarizes our current understanding of GBS interactions with other resident microbes at the mucosal surface from multiple angles, including clinical association studies, agriculture and aquaculture observations, and experimental animal model systems. We also include a comprehensive review of in vitro findings of GBS interactions with other bacterial and fungal microbes, both commensal and pathogenic, along with newly established animal models of GBS vaginal colonization and in utero or neonatal infection. Finally, we provide a perspective on emerging areas of research and current strategies to design microbe-targeting prebiotic or probiotic therapeutic intervention strategies to prevent GBS disease in vulnerable populations.

Microbiologic Epidemiology of Early-onset Sepsis in Neonates Born at ≥35 0/7 Weeks' Gestation in Korea During 2009-2018

BACKGROUND

Sepsis within the first 3 days of life remains a leading cause of neonatal mortality and morbidity. However, few studies have addressed the epidemiology of sepsis in late preterm and term neonates, particularly in Asia. We aimed to estimate the epidemiology of early-onset sepsis (EOS) in neonates born at ≥35 0/7 weeks' gestation in Korea.

METHODS

A retrospective study was conducted in neonates with proven EOS born at ≥35 0/7 weeks' gestation from 2009 to 2018 at seven university hospitals. EOS was defined as identifying bacteria from a blood culture within 72 hours after birth.

RESULTS

A total of 51 neonates (0.36/1,000 live births) with EOS were identified. The median duration from birth to the first positive blood culture collection was 17 hours (range, 0.2-63.9). Among the 51 neonates, 32 (63%) patients were born by vaginal delivery. The median Apgar score was 8 (range, 2-9) at 1 minute and 9 (range, 4-10) at 5 minutes. The most common pathogen was group B Streptococcus (n = 21; 41.2%), followed by coagulase-negative staphylococci (n = 7; 13.7%) and Staphylococcus aureus (n = 5, 9.8%). Forty-six (90.2%) neonates were treated with antibiotics on the first day of symptom onset, and 34 (73.9%) neonates received susceptible antibiotics. The overall 14-day case-fatality rate was 11.8%.

CONCLUSION

This is the first multicenter study on the epidemiology of proven EOS in neonates born at ≥35 0/7 weeks' gestation and found that group B Streptococcus was the most common pathogen in Korea.

The risk factors for Group B Streptococcus colonization during pregnancy and influences of intrapartum antibiotic prophylaxis on maternal and neonatal outcomes

BACKGROUND

Group B Streptococcus (GBS), also referred as Streptococcus agalactiae, is one of the leading causes of life-threatening invasive diseases such as bacteremia, meningitis, pneumonia and urinary tract infection in pregnant women and neonates. Rates of GBS colonization vary by regions, but large-sample studies on maternal GBS status are limited in southern China. As a result, the prevalence of GBS among pregnant women and its associated risk factors and the efficacy of intrapartum antibiotic prophylaxis (IAP) intervention in preventing adverse pregnancy and neonatal outcomes remain poorly understood in southern China.

METHODS

To fill this gap, we retrospectively analyzed demographic and obstetrical data of pregnant women who have undergone GBS screening and delivered between 2016 and 2018 in Xiamen, China. A total of 43,822 pregnant women were enrolled and only a few GBS-positive women did not receive IAP administration. Possible risk factors for GBS colonization were assayed by univariate and multivariate logistic regression analysis. Generalized linear regression model was applicated to analyze whether IAP is one of the impact factors of the hospital length of stay of the target women.

RESULTS

The overall GBS colonization rate was 13.47% (5902/43,822). Although women > 35 years old (P = 0.0363) and women with diabetes mellitus (DM, P = 0.001) had a higher prevalence of GBS colonization, the interaction between ages and GBS colonization was not statistically significant in Logistic Regression analysis (adjusted OR = 1.0014; 95% CI, 0.9950, 1.0077). The rate of multiple births was significantly dropped in GBS-positive group than that of GBS-negative group (P = 0.0145), with no significant difference in the rate of fetal reduction (P = 0.3304). Additionally, the modes of delivery and the incidences of abortion, premature delivery, premature rupture of membranes, abnormal amniotic fluid and puerperal infection were not significantly different between the two groups. The hospitalization stays of the subjects were not influenced by GBS infection. As for neonatal outcomes, the cases of fetal death in maternal GBS-positive group did not statistically differ from that in maternal GBS-negative group.

CONCLUSION

Our data identified that pregnant women with DM are at high risk of GBS infection and IAP is highly effective in prevention of adverse pregnancy and neonatal outcomes. This stressed the necessity of universal screening of maternal GBS status and IAP administration to the target population in China, and women with DM should be considered as priorities.

Maternity care provider acceptance of a future Group B Streptococcus vaccine - A qualitative study in three countries

INTRODUCTION

There are vaccines in clinical trials that target the bacterium Group B Streptococcus (GBS). When approved, GBS vaccines will be intended for administration to pregnant women to prevent infection in their infants. The success of any vaccine will depend on its' uptake in the population. Experience with prior maternal vaccines, e.g. influenza, Tdap and COVID-19 vaccines, teaches us that acceptance of vaccines, especially if novel, is challenging for pregnant women, and that provider recommendation is a key driver of vaccine uptake.

METHODS

This study investigated attitudes of maternity care providers towards the introduction of a GBS vaccine in three countries (the United States (US), Ireland, and the Dominican Republic (DR)) with different GBS prevalence and prevention practices. Semi-structured interviews with maternity care providers were transcribed and coded for themes. The constant comparative method, and inductive theory building were used to develop conclusions.

RESULTS

Thirty-eight obstetricians, 18 general practitioners and 14 midwives participated. There was variability in provider attitudes towards a hypothetical GBS vaccine. Responses ranged from enthusiasm to doubts over the need for a vaccine. Attitudes were influenced by perceived additional benefits of a vaccine over current strategy and confidence in the safety of vaccines during pregnancy. Knowledge, experience and approaches to GBS prevention differed geographically and according to provider type, and influenced how participants assessed the risks and benefits of a GBS vaccine.

CONCLUSION

Maternity care providers are engaged in the topic of GBS management and there is opportunity to leverage attitudes and beliefs that will support a strong recommendation for a GBS vaccine. However, knowledge of GBS, and of the limitations of current prevention strategies vary among providers in different regions, and between different provider types. Targeted educational efforts with antenatal providers should focus on highlighting safety data the potential benefits of vaccination over current strategies.

Safety and immunogenicity of the group B streptococcus vaccine AlpN in a placebo-controlled double-blind phase 1 trial

Group B streptococcus (GBS) is a leading cause of life-threatening neonatal infections and subsets of adverse pregnancy outcomes. Essentially all GBS strains possess one allele of the alpha-like protein (Alp) family. A maternal GBS vaccine, consisting of the fused N-terminal domains of the Alps αC and Rib (GBS-NN), was recently demonstrated to be safe and immunogenic in healthy adult women. To enhance antibody responses to all clinically relevant Alps, a second-generation vaccine has been developed (AlpN), also containing the N-terminal domain of Alp1 and the one shared by Alp2 and Alp3. In this study, the safety and immunogenicity of AlpN is assessed in a randomized, double-blind, placebo-controlled, and parallel-group phase I study, involving 60 healthy non-pregnant women. AlpN is well tolerated and elicits similarly robust and persistent antibody responses against all four Alp-N-terminal domains, resulting in enhanced opsonophagocytic killing of all Alp serotypes covered by the vaccine.

High Glucose Promotes Inflammation and Weakens Placental Defenses against E. coli and S. agalactiae Infection: Protective Role of Insulin and Metformin

Placentas from gestational diabetes mellitus (GDM) patients undergo significant metabolic and immunologic adaptations due to hyperglycemia, which results in an exacerbated synthesis of proinflammatory cytokines and an increased risk for infections. Insulin or metformin are clinically indicated for the treatment of GDM; however, there is limited information about the immunomodulatory activity of these drugs in the human placenta, especially in the context of maternal infections. Our objective was to study the role of insulin and metformin in the placental inflammatory response and innate defense against common etiopathological agents of pregnancy bacterial infections, such as E. coli and S. agalactiae, in a hyperglycemic environment. Term placental explants were cultivated with glucose (10 and 50 mM), insulin (50–500 nM) or metformin (125–500 µM) for 48 h, and then they were challenged with live bacteria (1 × 105 CFU/mL). We evaluated the inflammatory cytokine secretion, beta defensins production, bacterial count and bacterial tissue invasiveness after 4–8 h of infection. Our results showed that a GDM-associated hyperglycemic environment induced an inflammatory response and a decreased beta defensins synthesis unable to restrain bacterial infection. Notably, both insulin and metformin exerted anti-inflammatory effects under hyperglycemic infectious and non-infectious scenarios. Moreover, both drugs fortified placental barrier defenses, resulting in reduced E. coli counts, as well as decreased S. agalactiae and E. coli invasiveness of placental villous trees. Remarkably, the double challenge of high glucose and infection provoked a pathogen-specific attenuated placental inflammatory response in the hyperglycemic condition, mainly denoted by reduced TNF-α and IL-6 secretion after S. agalactiae infection and by IL-1β after E. coli infection. Altogether, these results suggest that metabolically uncontrolled GDM mothers develop diverse immune placental alterations, which may help to explain their increased vulnerability to bacterial pathogens.

Host inflammatory dynamics reveal placental immune modulation by Group B Streptococcus during pregnancy

Group B Streptococcus (GBS) is a pathobiont that can ascend to the placenta and cause adverse pregnancy outcomes, in part through production of the toxin β-hemolysin/cytolysin (β-h/c). Innate immune cells have been implicated in the response to GBS infection, but the impact of β-h/c on their response is poorly defined. We show that GBS modulates innate immune cell states by subversion of host inflammation through β-h/c, allowing worse outcomes. We used an ascending mouse model of GBS infection to measure placental cell state changes over time following infection with a β-h/c-deficient and isogenic wild type GBS strain. Transcriptomic analysis suggests that β-h/c-producing GBS elicit a worse phenotype through suppression of host inflammatory signaling in placental macrophages and neutrophils, and comparison of human placental macrophages infected with the same strains recapitulates these results. Our findings have implications for identification of new targets in GBS disease to support host defense against pathogenic challenge.

Comparative Analysis of the Molecular Characteristics of Group B Streptococcus Isolates Collected from Pregnant Korean Women Using Whole-genome Sequencing

Background

The incidence of early- and late-onset sepsis and meningitis in neonates due to maternal rectovaginal group B Streptococcus (GBS) colonization may differ with serotype distribution and clonal complex (CC). CC17 strains are associated with hypervirulence and poor disease outcomes. GBS serotypes are distinguished based on the polysaccharide capsule, the most important virulence factor. We determined the sequence type distribution of GBS isolates from pregnant women in Korea and validated whole-genome sequencing (WGS)-based prediction of antimicrobial susceptibility and capsular serotypes in GBS isolates.

Methods

Seventy-five GBS isolates collected from pregnant Korean women visiting Wonju Severance Christian Hospital, Wonju, Korea between 2017 and 2019 were subjected to WGS using the NovaSeq 6000 system (Illumina, San Diego, CA, USA). Multilocus sequence types, serotypes, antimicrobial resistance genes, and hemolysin operon mutations were determined by WGS, and the latter three were compared with the results of conventional phenotypic methods.

Results

The predominant lineage was CC1 (37.3%), followed by CC19 (32.0%), CC12 (17.3%), and CC17 (4.0%). All isolates were cps typeable (100%, (75/75), and 89.3% of cps genotypes (67/75) were concordant with serotypes obtained using latex agglutination. The cps genotypes of the 75 isolates were serotypes III (24.0%), V (22.7%), and VIII (17.3%). All isolates harboring intact ermB and tet were non-susceptible to erythromycin and tetracycline, respectively. Three non-hemolytic strains had 1-bp frameshift insertions in cylE.

Conclusions

The low prevalence of CC17 GBS colonization may explain the low frequency of neonatal GBS infections. WGS is a useful tool for simultaneous genotyping and antimicrobial resistance determination.

Prevalence of Group B Streptococcus maternal colonization, serotype distribution, and antimicrobial resistance in Sub-Saharan Africa: A systematic review and meta-analysis

OBJECTIVE

Group B Streptococcus (GBS)-associated maternal, perinatal, and neonatal mortality and morbidity disproportionately affects Sub-Saharan Africa (SSA). This systematic review and meta-analysis aimed to address the estimated prevalence, antimicrobial susceptibility, and serotype distribution of GBS isolates in SSA.

METHODS

This study was done according to PRISMA guidelines. MEDLINE/PubMed, CINAHL (EBSCO), Embase, SCOPUS, Web of Sciences databases, and Google Scholar were used to retrieve both published and unpublished articles. STATA software version 17 was used for data analysis. Forest plots using the random-effect model were used to present the findings. Heterogeneity was assessed using Cochrane chi-square (I²) statistics, while the Egger intercept was used to assess publication bias.

RESULTS

Fifty-eight studies that fulfilled the eligibility criteria were included for meta-analysis. The pooled prevalence of maternal rectovaginal colonization and vertical transmission of GBS were 16.06, 95% CI [13.94, 18.30] and 43.31%, 95% CI [30.75, 56.32], respectively. The highest pooled proportion of antibiotic resistance to GBS was observed in gentamicin (45.58%, 95% CI [4.12%, 91.23]), followed by erythromycin, (25.11%, 95% CI [16.70, 34.49]). The lowest antibiotic resistance was observed in vancomycin (3.84%, 95% CI [0.48, 9.22]). Our findings indicate that serotypes Ia/Ib/II/ III/and V cover almost 88.6% of serotypes in SSA.

CONCLUSIONS

The estimated high prevalence and resistance to different antibiotic classes observed in GBS isolates from SSA suggests the need for implementation of effective intervention efforts.

Gamma-Irradiated Non-Capsule Group B Streptococcus Promotes T-Cell Dependent Immunity and Provides a Cross-Protective Reaction

Group B Streptococcus (GBS) is a Gram-positive bacterium commonly found in the genitourinary tract and is also a leading cause of neonatal sepsis and pneumonia. Despite the current antibiotic prophylaxis (IAP), the disease burdens of late-onset disease in newborns and non-pregnant adult infections are increasing. Recently, inactivation of the pathogens via gamma radiation has been proven to eliminate their replication ability but cause less damage to the antigenicity of the key epitopes. In this study, the non-capsule GBS strain was inactivated via radiation (Rad-GBS) or formalin (Che-GBS), and we further determined its immunogenicity and protective efficacy as vaccines. Notably, Rad-GBS was more immunogenic and gave rise to higher expression of costimulatory molecules in BMDCs in comparison with Che-GBS. Flow cytometric analysis revealed that Rad-GBS induced a stronger CD4+ IFN-γ+ and CD4+IL-17A+ population in mice. The protective efficacy was measured through challenge with the highly virulent strain CNCTC 10/84, and the adoptive transfer results further showed that the protective role is reversed by functionally neutralizing antibodies and T cells. Finally, cross-protection against challenges with prevalent serotypes of GBS was induced by Rad-GBS. The higher opsonophagocytic killing activity of sera against multiple serotypes was determined in sera from mice immunized with Rad-GBS. Overall, our results showed that the inactivated whole-cell encapsulated GBS could be an alternative strategy for universal vaccine development against invasive GBS infections.

Group B streptococcus virulence factors associated with different clinical syndromes: Asymptomatic carriage in pregnant women and early-onset disease in the newborn

Background

Group B streptococcus (GBS) harbors many virulence factors but there is limited data regarding their importance in colonization in pregnancy and early-onset disease (EOD) in the newborn. We hypothesized that colonization and EOD are associated with different distribution and expression of virulence factors.

Methods

We studied 36 GBS EOD and 234 GBS isolates collected during routine screening. Virulence genes (pilus-like structures-PI-1, PI-2a, PI-2b; rib and hvgA) presence and expression were identified by PCR and qRT-PCR. Whole genome sequencing (WGS) and comparative genomic analyses were used to compare coding sequences (CDSs) of colonizing and EOD isolates.

Results

Serotype III (ST17) was significantly associated with EOD and serotype VI (ST1) with colonization. hvgA and rib genes were more prevalent among EOD isolates (58.3 and 77.8%, respectively; p < 0.01). The pilus loci PI-2b and PI-2a were more prevalent among EOD isolates (61.1%, p < 0.01), while the pilus loci PI-2a and PI-1 among colonizing isolates (89.7 and 93.1% vs. 55.6 and 69.4%, p < 0.01). qRT PCR analysis revealed that hvgA was barely expressed in colonizing isolates, even though the gene was detected. Expression of the rib gene and PI-2b was two-fold higher in EOD isolates compared to colonizing isolates. Transcription of PI-2a was three-fold higher in colonizing isolates compared to EOD isolates. ST17 isolates (associated with EOD) had a smaller genome size compared ST1 and the genome was more conserved relative to the reference strain and ST17 isolates. In a multivariate logistic regression analysis virulence factors independently associated with EOD were serotype 3, and PI-1 and PI-2a was protective.

Conclusion

There was a significant difference in the distribution of hvg A, rib, and PI genes among EOD (serotype III/ST17) and colonizing (serotype VI/ST1) isolates suggesting an association between invasive disease and these virulence factors. Further study is needed to understand the contribution of these genes to GBS virulence.

Cross-sectional study of the proportion of antibiotic use during childbirth in full-term deliveries in Finland

PURPOSE

In developed countries, data on the frequency of antibiotics given to mothers during childbirth are limited beyond the overall effect of all various prophylactic indications. Also, data on the impact of such antibiotics to the well-being of term babies are scarce. We aimed to characterize the frequency of antibiotic use during childbirth of term pregnancy. Secondly, we assessed whether the use of antibiotics was associated with any symptoms in infants.

METHODS

This was a cross-sectional study of 1019 term deliveries of women participating in the prospective Health and Early Life Microbiota (HELMi) birth cohort study between March 2016 and March 2018 in the capital region of Finland. The data on antibiotic use were collected from the hospital records.

RESULTS

In total, 37% of the mothers received antibiotics during childbirth and 100% in Caesarean Sects. (17% of the deliveries). Less than 5% of antibiotics were non-prophylactic. In vaginal deliveries, the most common indication (18%) was prophylaxis for Group B Streptococcus. The most frequently used antibiotics were cefuroxime (22%) and benzylpenicillin (15%), and 56% received only one dose. In infants exposed to antibiotics during delivery, defecation frequency was higher during the first months (p-value < 0.0001- 0.0145), and weight gain was higher at the age of three months (p-value 0.0371).

CONCLUSION

More than every third new-born in a developed country is exposed to antibiotics during birth. Our findings support the hypothesis that maternal antibiotics given during birth have an impact on the well-being of the infants. These findings should inform current policies for prophylactic antibiotics in childbirth.

Molecular Epidemiology of Group B Streptococcus Isolates from Pregnant Women with Premature Rupture of Membranes in Fuzhou, China

Objective

This study investigated the molecular epidemiology of Group B Streptococcus (GBS) in pregnant women with premature rupture of membranes (PROM) in Fuzhou region of China as a source of clinical reference.

Methods

GBS isolates were obtained from pregnant women with PROM. All isolates were genotyped, serotyped, and tested for drug-resistance and virulence genes using PCR and DNA sequencing. Antibiotic susceptibility testing was performed using the Vitek^® 2 automated system.

Results

Among the 140 GBS isolates, seventeen sequence types (STs) were identified, of which ST19 (20.0%) was the most prevalent, followed by ST862, ST10, and ST12. Three clonal complexes (CC19, CC10 and CC1) were identified. The predominant serotype was III (45.7%), followed by V (23.6%), Ib (18.6%), Ia (7.1%), and II (3.6%). The prevalence of multidrug resistance was 72.8% (102/140). All isolates were susceptible to penicillin G, ampicillin, quinupristin, linezolid, vancomycin, and tigecycline. The majority of isolates were resistant to erythromycin (70.0%), clindamycin (72.1%), and tetracycline (81.4%), and 28.6% of isolates were resistant to levofloxacin and moxifloxacin. Of the 98 erythromycin-resistant strains, mreA, ermB, mefA, mefE, ermA, and ermTR were detected in 100%, 70.4%, 49.0%, 22.4%, 13.3%, and 9.2%, respectively. No linB was detected among 101 clindamycin-resistant strains. Of the 114 tetracycline-resistant strains, tetM, tetK, tetL and tetO were detected in 52.6%, 61.4%, 7.9%, and 23.7%, respectively. Regarding virulence genes, all strains carried rib and hylB, followed by scpB (98.6%), and bca (80.7%), whereas only one strain carried bac.

Conclusion

ST19/III and ST862/III were the most prevalent GBS subtypes. Penicillin G remains a first-line antibiotic for intrapartum antibiotic prophylaxis and treatment of GBS infections. The prevalence of resistance to clindamycin, erythromycin, and tetracycline is high among GBS isolates in the Fuzhou region. ST862 and ST651 are emerging animal origin STs in human infections, and may become potential zoonotic threats.

Maternal colonization with group B Streptococcus and antibiotic resistance in China: systematic review and meta-analyses

BACKGROUND

Maternal rectovaginal colonization with group B Streptococcus (GBS) or Streptococcus agalactiae is the most common pathway for this disease during the perinatal period. This meta-analysis aimed to summarize existing data regarding maternal colonization, serotype profiles, and antibiotic resistance in China.

METHODS

Systematic literature reviews were conducted after searching 6 databases. Meta-analysis was applied to analyze colonization rate, serotype, and antimicrobial susceptibility of GBS clinical isolates in different regions of China. Summary estimates are presented using tables, funnel plots, forest plots, histograms, violin plots, and line plots.

RESULTS

The dataset regarding colonization included 52 articles and 195 303 pregnant women. Our estimate for maternal GBS colonization in China was 8.1% (95% confidence interval [CI] 7.2%-8.9%). Serotypes Ia, Ib, III, and V account for 95.9% of identified isolates. Serotype III, which is frequently associated with the hypervirulent clonal complex, accounts for 46.4%. Among the maternal GBS isolates using multilocus sequence typing (MLST), ST19 (25.7%, 289/1126) and ST10 (25.1%, 283/1126) were most common, followed by ST12 (12.4%, 140/1126), ST17 (4.8%, 54/1126), and ST651 (3.7%, 42/1126). GBS was highly resistant to tetracycline (75.1% [95% CI 74.0-76.3%]) and erythromycin (65.4% [95% CI 64.5-66.3%]) and generally susceptible to penicillin, ampicillin, vancomycin, ceftriaxone, and linezolid. Resistance rates of GBS to clindamycin and levofloxacin varied greatly (1.0-99.2% and 10.3-72.9%, respectively). A summary analysis of the bacterial drug resistance reports released by the China Antimicrobial Resistance Surveillance System (CARSS) in the past 5 years showed that the drug resistance rate of GBS to erythromycin, clindamycin, and levofloxacin decreased slowly from 2018 to 2020. However, the resistance rates of GBS to all 3 antibiotics increased slightly in 2021.

CONCLUSIONS

The overall colonization rate in China was much lower than the global colonization rate (17.4%). Consistent with many original and review reports in other parts of the world, GBS was highly resistant to tetracycline. However, the resistance of GBS isolates in China to erythromycin and clindamycin was greater than in other countries. This paper provides important epidemiological information, to assist with prevention and treatment of GBS colonization in these women.

Performance of the HiberGene Group B Streptococcus kit, a loop-mediated isothermal amplification-based assay for GBS screening during pregnancy

Timely and accurate detection of Group B Streptococcus (GBS) carriage in pregnant women allows for targeted peripartum prophylaxis. Replacing culture-based screening by molecular biology assays enables faster results obtention, better targeted antibiotic prophylaxis, and reduces the laboratory workload. Here, we present a comparative analysis between a Loop Mediated Isothermal Amplification assay (HiberGene GBS kit) and culture (gold-standard). The HiberGene GBS kit showed a sensitivity of 97.9% and a specificity of 96.8% compared with culture. The limit of detection was estimated at 10³ cfu/ml and results were obtained within 30 min. HiberGene GBS assay can be used for peripartum GBS screening and targeted antibiotic prophylaxis provided sample processing can be swiftly performed around the clock.

Molecular characteristics and antibiotic resistance mechanisms of clindamycin-resistant Streptococcus agalactiae isolates in China

Streptococcus agalactiae (Group B Streptococcus, GBS) is a major cause of neonatal infections with high morbidity and mortality, and clindamycin is the main antibiotic used to treat GBS infections in patients allergic to penicillin. We aimed to analyse the antibiotic sensitivity, sequence types, serotypes, virulence factors, and antibiotic resistance mechanisms of clinically isolated clindamycin-resistant S. agalactiae and provide basic data for the treatment, prevention, and control of clinical infection of S. agalactiae. A total of 110 strains of clindamycin-resistant S. agalactiae were collected from two tertiary hospitals in Hebei, China. We performed antibiotic sensitivity tests for 11 antibiotics on these strains and whole-genome sequencing analysis. All the strains were susceptible to penicillin, ampicillin, linezolid, vancomycin, tigecycline, and quinupristin-dalfopristin. Resistance to erythromycin, levofloxacin, tetracycline, and chloramphenicol were also observed. Genome sequence analysis revealed that all strains belonged to 12 sequence types (STs) related to six cloning complexes (CCs), namely CC10, CC19, CC23, CC651, CC1, and CC17. Five serotypes were identified, including IA, IB, II, III, and V. The most prominent resistance genes were mreA (100%) and ermB (81.8%). Furthermore, cfb, cylE, pavA and the gene cluster related to the pili were 100% present in all strains, followed by lmb (95.5%) and srr1 (67.2%). This study found that clindamycin-resistant S. agalactiae showed polymorphisms in molecular types and serotypes. Furthermore, multiple virulence factor genes have been identified in their genomes.

A randomized controlled trial of an oral probiotic to reduce antepartum group B Streptococcus colonization and gastrointestinal symptoms

BACKGROUND

Probiotics have been suggested as a strategy to reduce antenatal group B Streptococcus colonization. Although probiotics are known to improve gastrointestinal symptoms, this has not been studied during pregnancy.

OBJECTIVE

This study aimed to evaluate the efficacy of a probiotic to reduce: (1) standard-of-care antenatal group B Streptococcus colonization and colony counts and (2) gastrointestinal symptoms of pregnancy.

STUDY DESIGN

In a double-blind fashion, 109 healthy adult pregnant people were randomized to Florajen3 probiotic or placebo capsules once daily from 28 weeks' gestation until labor onset. Baseline vaginal and rectal study swabs for group B Streptococcus colony-forming units and microbiome analysis were collected at 28 and 36 weeks' gestation. Standard-of-care vaginal to rectal group B Streptococcus swabs were collected from all participants at 36 weeks' gestation and determined the need for intrapartum antibiotic prophylaxis. Data collection included solicitation of adverse events, demographic information, Antepartum Gastrointestinal Symptom Assessment score, yogurt ingestion, sexual activity, and vaginal cleaning practices.

RESULTS

A total of 83 participants completed the study to 36 weeks' gestation with no adverse events. Standard-of-care group B Streptococcus colonization was 20.4% in the control group and 15.4% in probiotic group participants (-5%; P=.73). The relative risk for positive standard-of-care vaginal-rectal group B Streptococcus colonization was 1.33 (95% confidence interval, 0.5-3.40) times higher in the control group than in the probiotic group (P=.55). There were no differences in median vaginal (P=.16) or rectal (P=.20) group B streptococcus colony-forming units at baseline or at 36 weeks (vaginal P>.999; rectal P=.56). Antepartum Gastrointestinal Symptom Assessment scores were similar at baseline (P=.19), but significantly decreased in probiotic group participants at 36 weeks (P=.02). No covariates significantly altered group B Streptococcus colonization. Significantly more Florajen3 bacteria components were recovered from the vaginal-rectal samples of probiotic group participants (32%; P=.04) compared with controls.

CONCLUSION

The findings of this study provided insufficient evidence for the clinical application of the Florajen3 probiotic intervention to reduce standard-of-care vaginal-rectal group B Streptococcus colonization. The prevalence of group B Streptococcus was lower than expected in the study population, and intervention adherence was poor. Probiotic bacteria colonization of the genitourinary tract occurred more in intervention group participants than in controls and significantly reduced gastrointestinal symptoms of pregnancy.

Characterization of Group B Streptococcus Recovered from Pregnant Women and Newborns Attending in a Hospital in Beijing, China

Purpose

We investigate the drug resistance, serotype and multilocus sequence typing (MLST) of Group B streptococcus (GBS) strains obtained from pregnant women and neonates in a hospital in Beijing.

Patients and Methods

In this cross-sectional study, 1470 eligible pregnant women at a gestational age of 35-37 weeks presented to our department between May 2015 and May 2016 were included. Vaginal and rectal samples from pregnant women together with sampling from neonatal samples were collected to screen GBS. GBS strains were subject to drug resistance and serotype analysis and MLST.

Results

GBS strains were isolated from 111 pregnant women (7.6%) and 6 neonates (0.99%) from 606 matched neonates. 102 strains from pregnant women and 3 strains from neonates were included in the drug sensitivity test, serotyping and MLST typing. All these strains were susceptible to ampicillin, penicillin, ceftriaxone, vancomycin, linezolid, and meropenem. Sixty strains (58.8%) showed multi-drug resistance. Serious cross-resistance was seen between erythromycin and clindamycin. There were eight serotypes, and 37 strains (36.3%) showed a serotype of type III serving as the major type. All 102 GBS strains isolated from pregnant samples could be divided into 18 STs types. They belonged to five clonal complexes and five single clones, with the predominant type of ST19/III, ST10/Ib, and ST23/Ia, with CC19 as the most common type. Three GBS strains isolated from neonates covered two serotypes (ie type III and Ia) that were consistent with those of the mothers.

Conclusion

Serotype III was the predominant serotype of GBS in this study. The predominant MLST type was ST19, ST10, and ST23, with ST19/III, ST10/Ib, and ST23/Ia serving as the most prevalent and CC19 as the most common clonal complex. GBS strains from neonates were consistent in the clonal complex, serotype, and MLST with these isolated from the mothers.

The Role of Regulator Catabolite Control Protein A (CcpA) in Streptococcus agalactiae Physiology and Stress Response

Streptococcus agalactiae is a leading cause of infections in neonates. This opportunistic pathogen colonizes the vagina, where it has to cope with acidic pH and hydrogen peroxide produced by lactobacilli. Thus, in the host, this bacterium possesses numerous adaptation mechanisms in which the pleiotropic regulators play a major role. The transcriptional regulator CcpA (catabolite control protein A) has previously been shown to be the major regulator involved in carbon catabolite repression in Gram-positive bacteria but is also involved in other functions. By transcriptomic analysis, we characterized the CcpA-dependent gene regulation in S. agalactiae. Approximately 13.5% of the genome of S. agalactiae depends on CcpA for regulation and comprises genes involved in sugar uptake and fermentation, confirming the role of CcpA in carbon metabolism. We confirmed by electrophoretic mobility shift assays (EMSAs) that the DNA binding site called cis-acting catabolite responsive element (cre) determined for other streptococci was effective in S. agalactiae. We also showed that CcpA is of capital importance for survival under acidic and oxidative stresses and is implicated in macrophage survival by regulating several genes putatively or already described as involved in stress response. Among them, we focused our study on SAK_1689, which codes a putative UspA protein. We demonstrated that SAK_1689, highly downregulated by CcpA, is overexpressed under oxidative stress conditions, this overexpression being harmful for the bacterium in a ΔccpA mutant. IMPORTANCE Streptococcus agalactiae is a major cause of disease burden leading to morbidity and mortality in neonates worldwide. Deciphering its adaptation mechanisms is essential to understand how this bacterium manages to colonize its host. Here, we determined the regulon of the pleiotropic regulator CcpA in S. agalactiae. Our findings reveal that CcpA is not only involved in carbon catabolite repression, but is also important for acidic and oxidative stress resistance and survival in macrophages.

Genomic Analysis of Group B Streptococcus from Neonatal Sepsis Reveals Clonal CC17 Expansion and Virulence- and Resistance-Associated Traits After Intrapartum Antibiotic Prophylaxis

BACKGROUND

Group B Streptococcus (GBS) is a leading cause of invasive neonatal infections. This study aimed to investigate the trend of GBS serotype and genotype change and their correlation with antimicrobial resistance before and after implementation of intrapartum antibiotic prophylaxis (IAP).

METHODS

We performed serotyping, whole-genome sequencing, antimicrobial susceptibility testing, and single-nucleotide polymorphism (SNP)-based phylogenetic analysis on 238 invasive GBS isolates collected from October 1998 to February 2020 in Taiwan.

RESULTS

There were 7 serotypes and 6 clonal complexes (CCs) among the 238 GBS isolates, and more than half of the isolates carried multiple antimicrobial resistance genes. The expansion of CC17 strains and the increase in late-onset disease occurred synchronously after the implementation of IAP. Analysis of the carriage isolates from pregnant women showed diverse serotype distribution in the IAP era. The antimicrobial susceptibility testing showed that all 238 strains were susceptible to ampicillin and penicillin, while the number of various resistance genes in GBS genomes was found increased with the expansion of CC17. Compared with reference genomes, 697 nonsynonymous SNPs in 443 protein-coding genes were CC17 specific.

CONCLUSIONS

The study revealed the expansion of GBS CC17 and the increase of late-onset disease that occurred simultaneously with the implementation of IAP. Although the susceptibility of CC17 to antimicrobial agents is not different from that of other sequence types at present, GBS with phenotypic resistance to antimicrobials may emerge in the future, given the environmental selection pressure and the continued accumulation of SNP mutations.

Group B Streptococcus: Virulence Factors and Pathogenic Mechanism

Group B Streptococcus (GBS) or Streptococcus agalactiae is a major cause of neonatal mortality. When colonizing the lower genital tract of pregnant women, GBS may cause premature birth and stillbirth. If transmitted to the newborn, it may result in life-threatening illnesses, including sepsis, meningitis, and pneumonia. Moreover, through continuous evolution, GBS can use its original structure and unique factors to greatly improve its survival rate in the human body. This review discusses the key virulence factors that facilitate GBS invasion and colonization and their action mechanisms. A comprehensive understanding of the role of virulence factors in GBS infection is crucial to develop better treatment options and screen potential candidate molecules for the development of the vaccine.

Updates on Group B Streptococcus Infection in the Field of Obstetrics and Gynecology

Group B Streptococcus (GBS, Streptococcus agalactiae) is a Gram-positive bacterium that is commonly found in the gastrointestinal and urogenital tracts. However, its colonization during pregnancy is an important cause of maternal and neonatal morbidity and mortality worldwide. Herein, we specifically looked at GBS in relation to the field of Obstetrics (OB) along with the field of Gynecology (GY). In this review, based on the clinical significance of GBS in the field of OBGY, topics of how GBS is being detected, treated, and should be prevented are addressed.

Group B Streptococcus and Pregnancy: Critical Concepts and Management Nuances

Importance

Group B Streptococcus (GBS) is a common pathogen with an effective treatment. However, it remains a significant cause of neonatal sepsis, morbidity, and mortality. The screening and management of this infection are some of the first concepts learned during medical training in obstetrics. However, effective screening and evidence-based management of GBS are nuanced with many critical caveats.

Objective

The objectives of this review are to discuss the essential aspects of GBS screening and management and to highlight recent changes to recommendations and guidelines.

Evidence Acquisition

Original research articles, review articles, and guidelines on GBS were reviewed.

Results

The following recommendations are based on review of the evidence and professional society guidelines. Screening for GBS should occur between 36 weeks and the end of the 37th week. The culture swab should go 2 cm into the vagina and 1 cm into the anus. Patients can perform their own swabs as well. Penicillin allergy testing has been shown to be safe in pregnancy. Patients with GBS in the urine should be treated at term with antibiotic prophylaxis, independent of the colony count of the culture. Patients who are GBS-positive with preterm and prelabor rupture of membranes after 34 weeks are not candidates for expectant management, as this population has higher rates of neonatal infectious complications. Patients with a history of GBS colonization in prior pregnancy who are GBS-unknown in this current pregnancy and present with labor should receive intrapartum prophylaxis. Work on the GBS vaccine continues.

Conclusions

Although all of the efforts and focus on neonatal early-onset GBS infection have led to lower rates of disease, GBS still remains a major cause of neonatal morbidity and mortality requiring continued vigilance from obstetric providers.

Group B Streptococcal Colonization among Pregnant Women and Neonates in a Tertiary Care Hospital in South India

OBJECTIVES

To assess the prevalence of maternal and neonatal group B Streptococcal colonization, incidence of neonatal systemic illness, and antibiotic sensitivity of isolates.

METHODS

This prospective cohort study was conducted in a South Indian tertiary care hospital. Rectovaginal swabs from pregnant mothers at 36^0/7-37^6/7 wk gestation and throat and rectal swabs from their neonates at 48 h of age were collected. Presence of group B Streptococcus (GBS) was identified by broth enrichment step, and traditional microbiologic methods and antibiotic sensitivity of isolates was noted. All mothers received intrapartum antibiotic prophylaxis (IAP). Culture-positive sepsis, clinical sepsis, pneumonia, meningitis, and urinary tract infection were defined as neonatal systemic illness. Neonates of colonized mothers were followed at 3 mo for late-onset sepsis.

RESULTS

Of the 310 mothers, 40 were GBS colonized (prevalence: 12.9%; 95% CI 9.2%, 17.6%). None of the neonates were colonized. Maternal GBS colonization was significantly associated with premature rupture of membrane (RR - 2.93, 95% CI - 1.66-5.16) and neonatal systemic illness (RR - 2.78, 95% CI - 1.39-5.54). Positive correlation was noted between duration of IAP ≤ 4 h and neonatal illness and between maternal GBS colonization and Apgar at 1 min ≤ 4. Clindamycin resistance was noted in 20%. All neonates remained well at 3 mo follow-up.

CONCLUSION

High maternal colonization alerts the need for GBS screening in India. Clindamycin resistance among GBS isolates questions its effectiveness as alternative therapy in penicillin allergy.

Ali G, Alzubaidi K, Ali B, Ismail A, Daghfal J, Almaslamani M, Hadi HA. Microbiological and clinical characteristics of invasive Group B Streptococcal blood stream infections in children and adults from Qatar

INTRODUCTION

Group B Streptococci (GBS) colonize almost one third of human gastrointestinal and genitourinary tracts, particularly in females. The aim of this study is to evaluate the epidemiology, microbiological characteristics, and clinical outcomes of invasive GBS disease in Qatar from all age groups.

METHODS

A retrospective study was conducted on patients with confirmed GBS blood stream infections during the period between January 2015 and March 2019. Microbiological identification was performed using automated BD PhoenixTM system, while additional antimicrobial susceptibility tests were performed using E test and disc diffusion methods.

RESULT

During the four years period, the incidence steadily rose from 1.48 to 2.09 cases per 100.000 population. Out of 196 confirmed cases of invasive GBS infections, the majority were females (63.7%, 125/196) of which 44.8% were pregnant and 53.6% were colonized. Three distinct affected age groups were identified: children ≤ 4 years of age (35.7%), young adults 25-34 (20.9%) and the elderly ≥ 65 year (17.4%). Presenting symptoms were mild with fever in 53% of cases while 89% of cases had Pitt bacteraemia score of ≤ 2. Isolates were universally sensitive to penicillin, ceftriaxone, and vancomycin at 100% but with significant resistance to erythromycin (49%) and clindamycin (28.6%) while 16.8% had inducible clindamycin resistance. Clinical outcomes showed cure rate of 87.25% with complications in (8.76%) and 4% mortality.

CONCLUSION

There is a rising trend of Group B Streptococcal blood stream infections in Qatar with significantly high clindamycin and erythromycin resistance rates. Universal susceptibility rates were demonstrated for penicillin, ceftriaxone, and vancomycin.

An Initial Survey on the Prevalence of Group B Streptococcus (GBS) among Yemeni Pregnant Women in Sana’a City

Background

Infection with group B Streptococcus (GBS) is still a neonatal life-threatening illness, especially in developing countries such as Yemen.

Objective

This study was aimed at determining the vaginal colonization rate and antibiotic susceptibility pattern of GBS among Yemeni pregnant women.

Methods

We conducted a cross-sectional study over a four-month period involving 210 pregnant women at the 35th to 39th gestational weeks who visited Gaza medical center in Sana'a city, Yemen. The collected vaginal swab specimen was inoculated in the Todd-Hewitt enrichment broth and incubated for 24 h and then subcultured on a 5% human blood agar plate. All positive cultures identified as GBS were subjected to antibiotic susceptibility tests using the disk diffusion method.

Results

Out of 210 recruited pregnant women, 23 (10.95%) were GBS vaginal carriers. All GBS isolates were sensitive to penicillin, ampicillin, levofloxacin, cefotaxime, and vancomycin.

Conclusion

Based on the study's results, approximately eleven out of every 100 pregnant women in Sana'a city are vaginally colonized by GBS. Beta-lactam antibiotics remain the drug of choice to treat and prevent GBS infections. A prenatal screening policy is urgently needed for Yemeni pregnant women.

Sublingual immunisation with GBS serotype III capsular polysaccharide-tetanus toxoid conjugate vaccine induces systemic and mucosal antibody responses which are opsonophagocytic and inhibit GBS colonisation of vaginal epithelial cells

No vaccines are currently licensed against Group B streptococcus (GBS), an important cause of morbidity and mortality in babies and adults. Using a mouse model, and in vitro opsonophagocytosis and colonisation assays, we evaluated the potential of a sublingually-administered polysaccharide-conjugate vaccine against GBS serotype III. Sublingual immunisation of mice with 10 µg of GBS conjugate vaccine once a week for 5 weeks induced a substantial systemic IgG anti-polysaccharide response which was similar to the level induced by subcutaneous immunsation. In addition, sublingual immunisation also induced mucosal (IgA) antibody responses in the mouth, intestines and vagina. Immune sera and intestinal washes were functionally active at mediating killing of the homologous GBS serotype III in an opsonophagocytosis assay. In addition, intestinal and vaginal washes inhibited the colonisation of mouse vaginal epithelial cells by the vaccine homologous strain. These results suggest that, in addition to the induction of high levels of IgG antibodies that could be transduced from the immunised mother to the foetus to protect the newborn against GBS infection, sublingual immunisation can elicit a substantial mucosal antibody response which might play an important role in the prevention of GBS colonisation in immunised women, thereby eliminating the risk of GBS transmission from the mother to the baby during pregnancy or at birth.

Changes in pathogens of neonatal bacterial meningitis over the past 12 years: a single-center retrospective study

BACKGROUND

Bacterial meningitis is a serious central nervous system infection associated with high morbidity and mortality during the neonatal period, while the pathogen distribution was rarely reported on a large scale in China. This study aimed to investigate the distribution and change trends of neonatal bacterial meningitis pathogens in Children's Hospital of Fudan University over the past 12 years.

METHODS

This retrospective study included all cases diagnosed with neonatal bacterial meningitis and admitted to our hospital from 2009 to 2020.

RESULTS

Totally 231 cases were enrolled, including 128 (55.4%) for male, 72 (31.2%) for premature infants, 48 (20.8%) for early-onset meningitis. The most common pathogens were Escherichia coli (E. coli) (39.0%) and Group B Streptococcus (GBS) (22.1%). Gram-negative bacteria were more common in preterm infants than in full-term infants (P=0.005). GBS was more common in term infants (P=0.000); Klebsiella pneumoniae (P=0.000) and Enterobacter cloacae (P=0.034) were more common in preterm infants. Gram-positive bacteria were more frequent in early-onset meningitis than in late-onset meningitis (P=0.002). Both E. coli (46.3% vs. 30.9%, P=0.017) and GBS (29.8% vs. 13.6%, P=0.003) increased, and Enterococcus (3.3% vs. 12.7%, P=0.008) decreased significantly in the epoch from 2015 to 2020 compared with the epoch from 2009 to 2014.

CONCLUSIONS

GBS and E. coli are the most common pathogens of neonatal bacterial meningitis in our hospital, and both have shown an upward trend over the past 12 years.

Invasive group B Streptococcus strains and clinical characteristics in Danish infants from 1999 to 2009

Background

Group B Streptococcus (GBS) infection in infants may result in both respiratory, cardiovascular, and neurological dysfunction and ultimately death of the infant. Surveillance of GBS strains in infants and their clinical characteristics guide development of effective vaccines and other potential treatments and may have implications for future prognostics and infant care. Therefore, we aimed to study GBS serotypes and clonal complexes (CC) in Danish infants with early onset infection (EOD) (0–6 days of life) and late-onset infection (LOD) (7–89 days of life) and to estimate the association between GBS strain and different clinical outcomes.

Methods

We included Danish infants less than 3 months of age with GBS isolates from blood or cerebrospinal fluid between 1999 and 2009. GBS isolates were analyzed by serotyping and multilocus sequence typing with classification of isolates into clonal complexes. Clinical characteristics were obtained by questionnaires completed by tending pediatrician including gestational age, Apgar scores, age at onset, meningitis, symptom severity, treatment duration, and mortality. Symptom severities were reported within neurological symptoms, need for respiratory or circulatory support, and treatment of disseminated intravascular coagulation.

Results

A total of 212 GBS isolates were collected with 129 from EOD and 83 from LOD. The dominating GBS strains were III/CC17 (41%), Ia/CC23 (17%), III/CC19 (15%), Ib/CC8-10 (7%), and V/CC1 (6%). Strain Ia/CC23 was mostly found in EOD, while III/CC17 was widespread in LOD, though being the most common in both EOD and LOD. Strain III/CC17 and Ia/CC23 had highest percentage of samples from cerebrospinal fluid (26%), while III/CC19 had the least (8%). Strain III/CC19 had highest mortality with about one fifth of infected infants dying (22%) followed by Ia/CC23 (16%), Ib/CC8-10 (9%), and then III/CC17 (6%). The symptom severity varied between strains, but with no strain consistently resulting in more severe symptoms.

Conclusion

Some potential differences in disease severity were observed between the different strains. These findings emphasize the continuous need for multimodal surveillance of infant GBS strains and their clinical characteristics to optimize development of GBS vaccines and other potential treatments.

Comparison of Early-Onset Sepsis Risk-Stratification Algorithms in Neonates in a Kenyan Nursery

BACKGROUND AND OBJECTIVES

Risk stratification algorithms (RSAs) can reduce antibiotic duration (AD) and length of stay (LOS) for early-onset sepsis (EOS). Because of higher EOS and antibiotic resistance rates and limited laboratory capacity, RSA implementation may benefit low- and middle-income countries (LMIC). Our objective was to compare the impact of 4 RSAs on AD and LOS in an LMIC nursery.

METHOD

Neonates <5 days of age admitted for presumed sepsis to a Kenyan referral hospital in 2019 (n = 262) were evaluated by using 4 RSAs, including the current local sepsis protocol ("local RSA"), a simplified local protocol ("simple RSA"), an existing categorical RSA that uses infant clinical examination and maternal risk factors (CE-M RSA) clinical assessment, and the World Health Organization's Integrated Management of Childhood Illness guideline. For each RSA, a neonate was classified as at high, moderate, or low EOS risk. We used к coefficients to evaluate the agreement between RSAs and McNemar's test for the direction of disagreement. We used the Wilcoxon rank test for differences in observed and predicted median AD and LOS.

RESULTS

Local and simple RSAs overestimated EOS risk compared with CE-M RSA and the Integrated Management of Childhood Illness guideline. Compared with the observed value, CE-M RSA shortened AD by 2 days and simple RSA lengthened AD by 2 days. LOS was shortened by 4 days by using CE-M RSA and by 2 days by using the local RSA.

CONCLUSIONS

The local RSA overestimated EOS risk compared with CE-M RSA. If implemented fully, the local RSA may reduce LOS. Future studies will evaluate the prospective use of RSAs in LMICs with other interventions such as observation off antibiotics, biomarkers, and bundled implementation.

Molecular Epidemiology of Group B Streptococci in Lithuania Identifies Multi-Drug Resistant Clones and Sporadic ST1 Serotypes Ia and Ib

Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of neonatal infections. Yet, detailed assessment of the genotypic and phenotypic factors associated with GBS carriage, mother-to-baby transmission, and GBS infection in neonates and adults is lacking. Understanding the distribution of GBS genotypes, including the predominance of different serotypes, antimicrobial resistance (AMR) genes, and virulence factors, is likely to help to prevent GBS diseases, as well as inform estimates of the efficacy of future GBS vaccines. To this end, we set out to characterise GBS isolates collected from pregnant and non-pregnant women in Kaunas region in Lithuania. Whole genome sequences of 42 GBS isolates were analysed to determine multi-locus sequence typing (MLST), the presence of acquired AMR and surface protein genes, and the phylogenetic relatedness of isolates. We identified serotypes Ia (42.9%, 18/42), III (33.3%, 14/42), V (21.4%, 9/42), and a single isolate of serotype Ib. Genomic analyses revealed high diversity among the isolates, with 18 sequence types (STs) identified, including three novel STs. 85.7% (36/42) of isolates carried at least one AMR gene: tetM or tetO (35/42), ermB or lsaC (8/42) and ant6-Ia and aph3-III (2/42). This study represents the first genomic analysis of GBS isolated from women in Lithuania and contributes to an improved understanding of the global spread of GBS genotypes and phenotypes, laying the foundations for future GBS surveillance in Lithuania.

Pathogens Identified by Minimally Invasive Tissue Sampling in India and Pakistan From Preterm Neonatal Deaths: The PURPOSE Study

BACKGROUND

We identified pathogens found in internal organs and placentas of deceased preterm infants cared for in hospitals in India and Pakistan.

METHODS

Prospective, observational study conducted in delivery units and neonatal intensive care units. Tissue samples from deceased neonates obtained by minimally invasive tissue sampling and placentas were examined for 73 different pathogens using multiplex polymerase chain reaction (PCR).

RESULTS

Tissue for pathogen PCR was obtained from liver, lung, brain, blood, cerebrospinal fluid, and placentas from 377 deceased preterm infants. Between 17.6% and 34.1% of each type of tissue had at least 1 organism identified. Organism detection was highest in blood (34.1%), followed by lung (31.1%), liver (23.3%), cerebrospinal fluid (22.3%), and brain (17.6%). A total of 49.7% of the deceased infants had at least 1 organism. Acinetobacter baumannii was in 28.4% of the neonates compared with 14.6% for Klebsiella pneumoniae, 11.9% for Escherichia coli/Shigella, and 11.1% for Haemophilus influenzae. Group B streptococcus was identified in only 1.3% of the neonatal deaths. A. baumannii was rarely found in the placenta and was found more commonly in the internal organs of neonates who died later in the neonatal period. The most common organism found in placentas was Ureaplasma urealyticum in 34% of the samples, with no other organism found in >4% of samples.

CONCLUSIONS

In organ samples from deceased infants in India and Pakistan, evaluated with multiplex pathogen PCR, A. baumannii was the most commonly identified organism. Group B streptococcus was rarely found. A. baumannii was rarely found in the placentas of these deceased neonates.

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

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.

Molecular characterization and antimicrobial resistance of Streptococcus agalactiae isolated from pregnant women in Japan, 2017–2021

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Group B streptococcus (GBS) in pregnant women was studied in northern Japan.

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Colonizing GBS was isolated from 7.0% (n=76/1090) of the pregnant women.

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Capsular serotype III/ST335, Ia/ST23, III/ST17, and V/ST1 lineages were dominant.

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Levofloxacin resistance was found in 15.8%, with serotype Ib being the most common.

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Most levofloxacin-resistant isolates belonged to serotype Ib/CC10 or V/CC19.

Objectives

This study aimed to elucidate the molecular characteristics and antimicrobial resistance of Streptococcus agalactiae (group B streptococcus, GBS) colonizing pregnant women in Japan.

Methods

GBS isolates obtained from screening of pregnant women from 2017 to 2021 were analyzed for capsular serotype, sequence type (ST), and antimicrobial susceptibility. For levofloxacin-resistant isolates, mutations in the quinolone resistance-determining regions (QRDRs) of the gyrA, gyrB, and parC genes were analyzed.

Results

Seventy-six GBS isolates were recovered from 1090 women (isolation rate: 7.0%). Of the 76 isolates, serotype III (31.6%) was the most prevalent, followed by V (19.7%), Ia (17.1%), and Ib (10.5%). Among the 22 STs identified, capsular serotype III/ST335-clonal complex (CC) 19 lineage was dominant (13.2%), followed by Ia/ST23, III/ST17, and V/ST1. Levofloxacin resistance was detected in 15.8% (n=12) of all the isolates, with serotype Ib being the most common. Most levofloxacin resistant isolates belonged to serotype Ib/CC10 or serotype V/CC19, with double mutations in the QRDRs, Ser81Leu in GyrA and Ser79Phe in ParC.

Conclusions

The present study indicates the prevalence of the serotype III/ST335 (CC19) lineage, and the spread of serotype Ib/CC10 and serotype V/CC19 lineages, which are responsible for levofloxacin resistance in colonizing GBS in pregnant women in Japan.

Protective Effect of Lactobacillus crispatus against Vaginal Colonization with Group B Streptococci in the Third Trimester of Pregnancy

Background: A normal vaginal microbiota may protect the vaginal mucosa from colonization by potentially pathogenic bacteria, including group B streptococci (GBS). The aim of this study was to investigate the association between colonization with GBS and the presence of specific vaginal microbiota isolated from vaginal swabs in the third trimester of pregnancy. Methods: A semiquantitative culture of 1860 vaginal swabs from consecutive pregnant women in their third trimester was analyzed. The dominant bacteria, including lactobacilli, were identified using MALDI-TOF mass spectrometry. An enrichment culture for GBS was performed on the swabs. GBS colonization correlated with the bacteria isolated at the same time. Results: Lactobacilluscrispatus was isolated in 27.5% of the cultures, followed by L. jensenii (13.9%), L. gasseri (12.6%), and L. iners (10.1%). The presence of lactobacilli as a group, and of L. crispatus, inversely correlated with GBS colonization (OR = 0.44 and OR = 0.5, respectively; both with p < 0.001). Other microorganisms, including Gardnerella vaginalis, mixed aerobic bacteria and yeasts, were not associated with GBS colonization. Conclusions: Lactobacilli, especially L. crispatus, may prevent GBS colonization in pregnancy. Maintaining a normal vaginal microbiota could be an effective method for the antibiotic-free prevention of invasive GBS infections in neonates.