Group B Streptococci serotype distribution in pregnant women in Ghana: assessment of potential coverage through future vaccines

The increasing burden of group B Streptococcus from 2013 to 2023: a retrospective cohort study in Beijing, China

Group B Streptococcus (GBS) is a leading pathogen responsible for fatal infections in newborns primarily due to vertical transmission from colonized mothers. Cases of invasive GBS infections in adults have also increased and attracted attention recently. To comprehensively understand the evolving burden of vaginal GBS carriage in pregnant and non-pregnant women, as well as the trends in invasive GBS diseases and antibiotic resistance in China, we conducted a retrospective study using data from a large tertiary hospital in Beijing from 2013 to 2023. Over the past decade, improvements in GBS screening methods for pregnant women have significantly increased the GBS recovery rate. The detection rate of GBS and its proportion among vaginal pathogens have shown a gradual increase in GBS colonization in both pregnant and non-pregnant women. An analysis of vaginal pathogen composition revealed variations in GBS prevalence across different age groups, as well as a potential competitive relationship between GBS and Enterococcus faecalis in the vaginal environment. Additionally, we analyzed 165 invasive GBS cases, including three in newborns. The incidence of invasive GBS cases has risen since 2016, particularly among individuals over the age of 40. The 5,858 GBS isolates exhibited notably high resistance rates to erythromycin (72.2%), clindamycin (60%), and levofloxacin (50.1%), with 30.8% classified as multidrug-resistant. Importantly, invasive GBS strains exhibited a higher resistance rate to levofloxacin (61.2%) compared to colonizing strains (49.8%). This study highlights the importance of continuous screening and monitoring for GBS, especially given the concerning antibiotic resistance rates of GBS.IMPORTANCEGroup B Streptococcus (GBS) is an important pathogen that commonly causes infections in newborns and the elderly. This retrospective study provides a comprehensive analysis of GBS strains isolated from a large tertiary hospital in Beijing between 2013 and 2023, revealing an increasing colonization rate of GBS in both pregnant and non-pregnant women. Analysis of vaginal pathogens indicates a growing proportion of GBS among vaginal pathogens. Additionally, the high resistance rates of GBS to erythromycin, clindamycin, and levofloxacin, as well as the prevalence of multidrug resistance, are issues that merit attention. We also examined the differences in resistance rates of GBS strains from various sample types, finding that the levofloxacin resistance rate in GBS strains causing invasive infections was significantly higher than in colonizing strains. This study provides new data and insights for clinical research on GBS.

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.

Frequency and Antibiotic Susceptibility Patterns of Streptococcus agalactiae Strains Isolated from Women in Yaounde, Cameroon

Group B Streptococcus (GBS), a commensal in the body, causes a wide range of infectious diseases. This bacterium is dangerous for pregnant women and their babies, in whom it is responsible for early neonatal bacterial sepsis (EOS). The colonisation levels of GBS and its resistance profile to antibiotics provide important information that is useful for orienting prevention strategies. There are few data available on the subject on the determination of resistance phenotypes in Cameroon. We therefore aimed to determine the prevalence of colonisation and antibiotic resistance, including patterns of inducible resistance to clindamycin, of GBS in the city of Yaounde. To achieve this goal, a prospective cross-sectional study with an analytical component was carried out from 28 June to 29 August 2020 at the BIOSANTE laboratory and the Yaounde Gynaeco-Obstetrics and Paediatrics hospital. Vaginal swabs and urine were collected from 163 women. This samples were analysed using 5% defibrinated sheep blood agar and chocolate plus polyvitex agar. The isolates were identified using the morphology of the colony, Gram staining, haemolysis, catalase tests and latex grouping tests. Antibiotic susceptibility testing was carried out by disk diffusion method following the recommendations of the ACFSM 2019. The double disk diffusion method was used to identify isolates with clindamycin-inducible resistance. Our data were analysed with SPSS version 2.1. The results obtained showed that the overall prevalence of colonisation by GBS was 37% (57/163), or 40.3% in non-pregnant women and 59.7% in pregnant women. Pregnancy (p-value = 0.019) and earlier (from the second semester of pregnancy) gestational age (p-value = 0.025) constituted the risk factors of maternal colonisation by GBS. In addition, the strains of GBS were resistant to all 16 antibiotics tested. A D test showed that 64.7% of GBS strains were constitutively resistant to clindamycin. We also note the presence of M phenotypes. As a whole, our results demonstrated that the rate of GBS colonisation in this study was similar to or higher than those in previous reports in Cameroon. All these results indicate that attention should be paid to this bacterium in the monitoring of antimicrobial resistance and in the care of pregnant women and newborns.

Group B Streptococcal Colonization in African Countries: Prevalence, Capsular Serotypes, and Molecular Sequence Types

Streptococcus agalactiae or group B streptococcus (GBS) is a commensal of the gastrointestinal and genitourinary tracts of healthy women and an important cause of neonatal invasive infections worldwide. Transmission of bacteria to the newborn occurs at birth and can be prevented by intrapartum antibiotic prophylaxis. However, this not available in resource limited settings in Africa, which carries a particular high burden of disease. Serotype based vaccines are in development and present a suitable alternative to prevent neonatal infections. To be able to assess vaccine efficacy, knowledge and surveillance of GBS epidemiological data are required. This review summarizes investigations about the serotype distribution and the multi-locus sequence types (MLST) found in different African countries. While most serotypes and MLST data are comparable to findings from other continents, some specific differences exist. Serotype V is predominant among colonizing maternal strains in many different African countries. Serotypes that are rarely detected in western industrialized nations, such as serotypes VI, VII and IX, are prevalent in studies from Ghana and Egypt. Moreover, some specific MLST sequence types that seem to be more or less unique to Africa have been detected. However, overall, the data confirm that a hexavalent vaccine can provide broad coverage for the African continent and that a protein vaccine could represent a promising alternative.

A review of antibiotic resistance in Group B Streptococcus: the story so far

Group B Streptococcus (GBS) is the leading cause of neonatal disease worldwide, and invasive disease in adults is becoming more prevalent. Currently, some countries adopt an intrapartum antibiotic prophylaxis regime to help prevent the transmission of GBS from mother to neonate during delivery. This precaution has reduced the incidence of GBS-associated early-onset disease; however, rates of late-onset disease and stillbirths associated with GBS infections remain unchanged. GBS is still recognized as being universally susceptible to beta-lactam antibiotics; however, there have been reports of reduced susceptibility to beta-lactams, including penicillin, in some countries. Resistance to second-line antibiotics, such as erythromycin and clindamycin, remains high amongst GBS, with several countries noting increased resistance rates in recent years. Moreover, resistance to other antibiotic classes, such as fluoroquinolones and aminoglycosides, also continues to rise. In instances where patients are allergic to penicillin and second-line antibiotics are ineffective, vancomycin is administered. While vancomycin, a last resort antibiotic, still remains largely effective, there have been two documented cases of vancomycin resistance in GBS. This review provides a comprehensive analysis of the prevalence of antibiotic resistance in GBS and outlines the specific resistance mechanisms identified in GBS isolates to date.

Group B Streptococcus (Streptococcus agalactiae)

Invasive disease due to group B Streptococcus infection (Streptococcus agalactiae) results in a wide spectrum of clinical disease. In North America, serotypes Ia, Ib, II, III, and V are most frequently associated with invasive disease. Group B Streptococcus remains a continuing source of morbidity and mortality in high-risk populations, including pregnant women, neonates, and the elderly; an increasing incidence of invasive disease has been observed in nonpregnant adults. Group B Streptococcus remains the most common culture-confirmed neonatal bacterial infection in the United States and is a significant source of neonatal morbidity globally. Intrapartum antibiotic prophylaxis has reduced the incidence of early-onset neonatal disease without a notable impact on the incidence of late-onset neonatal disease. Penicillin G remains the mainstay of therapy, although reduced penicillin susceptibility has been observed in select isolates. Increased frequency of resistance to non-beta-lactam antibiotics, including clindamycin, erythromycin, and fluoroquinolones, has been observed, with some isolates demonstrating resistance to vancomycin. The development and implementation of strategies to identify hosts, treat judiciously with antimicrobials with the narrowest spectra, and prevent invasive disease, with vaccines, are essential to reduce the burden of group B Streptococcus disease.

Streptococcus agalactiae maternal colonization, antibiotic resistance and serotype profiles in Africa: a meta-analysis

Background

Maternal rectovaginal colonization with Streptococcus agalactiae (Group B Streptococcus or GBS) is the most common route for the GBS disease in the perinatal period. The knowledge of maternal colonization, antibiotic resistance and serotype profiles is substantially needed to formulate the broad vaccine. However, it has not been estimated in Africa. This meta-analysis was aimed to determine the pooled prevalence of colonization, antibiotic resistance and serotype profiles of GBS reported in Africa.

Methods

Potentially relevant studies from 1989 to 31th January, 2019 were retrieved from the Medline/PubMed, EMBASE, HINARI online databases, periodicals and by requesting authors. Unpublished studies retrieved from grey literature through Google and Google Scholar. Pooled estimates were calculated using the random effect model. Subgroup analysis was done to investigate the burden of colonization across sub-regions, sampling site and countries. Summary estimates were presented using words, Forest plots and Tables. Heterogeneity was assessed using the I² statistic.

Results

Eighty-three articles were assessed, of which 57 studies conducted in five sub-regions with 21 countries (22,206 pregnant women) met pre-specified inclusion criteria. The overall estimate of recto-vaginal colonization was 19.3% (95% CI 16.9, 21.7). The highest estimate was observed in Southern Africa, 23.8% (95% CI 18.7, 28.9), followed by Northern Africa, 22.7% (95% CI 18.2, 27.2) while the lowest was driven from the Eastern Africa, 15.4% (95% CI 12.1, 18.7). Considerable heterogeneity across and within regions, sampling site, screening methods and countries (I² > 75%); and the publication bias were observed (p = 0.031). GBS showed the highest resistance to tetracycline. Resistance to penicillin, amoxicillin, chloramphenicol, ampicillin, ceftriaxone, ciprofloxacin, erythromycin, vancomycin and clindamycin also observed. The V, III, Ia, Ib, and II serotypes altogether were accounted 91.8% in the African studies.

Conclusions

The pooled estimate of the maternal colonization with GBS was 19.3% which is equivalent with other many primary and review reports worldwide. The most antibiotic resistance estimate was recorded in the tetracycline followed by penicillin. Five serotypes were the most prevalent in Africa and more data on the antibiotic résistance and serotype distribution patterns are needed from developing countries to devise the effective preventive measures. In addition, the antibiotic susceptibility test methods used in the Africa shall be assessed for its quality.

Trial registration Prospero Registration Number CRD42018094525

Streptococcus agalactiae from Ethiopian pregnant women; prevalence, associated factors and antimicrobial resistance: alarming for prophylaxis

Background

Maternal Streptococcus agalactiae (Group B Streptococcus, GBS) colonization rates and its antibiotic resistance patterns provide important information useful in guiding prevention strategies. There is a paucity of evidence about GBS in the Amhara National Regional State, Ethiopia.

Objective

To determine colonization prevalence, associated risk factors, and antibiotics resistance including inducible clindamycin resistance patterns of GBS among Ethiopian pregnant women.

Methods

A prospective cross-sectional study was conducted from 1st December 2016 to 30th November 2017 at the University of Gondar Referral hospital delivery ward. Combined recto-vaginal swabs were collected from 385 pregnant women and analyzed at the University of Gondar Bacteriology Laboratory by using LIM broth and 5% defibrinated sheep blood agar culture methods. Isolates were identified by using colony morphology, gram reaction, hemolysis, and CAMP test. Antibiotic susceptibility test was done using the disc diffusion method. Double disc diffusion method was used to identify inducible clindamycin resistance isolates. Data were analyzed by SPSS version 20 software. p ≤ 0.05 was considered as statistically significant.

Results

The overall prevalence of maternal GBS colonization was 25.5% (95% CI 21–29.5%). Experiencing meconium stained amniotic fluid (AOR = 3.018, 95% CI 1.225, 7.437), and longer duration of premature rupture of membrane (AOR = 1.897, 95% CI 1.014, 3.417) were statistically significant to maternal colonization. Furthermore, GBS resistant to 0 (8.2%), 1 (25.5%) and 3 (39.8%) or more antibiotics were identified. A D-test showed 15.2% inducible clindamycin resistant GBS. Constitutive macrolide lincosamide–streptogramin_B, L-, and M-phenotypes were also detected.

Conclusions

Maternal GBS colonization rate in this study was higher compared to the previous reports in Ethiopia. This much prevalence and antibiotics resistance results are the clue to which attention shall be given to this bacterium during management of pregnant women and the newborns.

Carriage and serotype distribution of Streptococcus agalactiae in third trimester pregnancy in southern Ghana

BACKGROUND

The aim of this study was to determine the prevalence of Streptococcus agalactiae (group B streptococci, GBS) among healthy, pregnant women attending antenatal care at different study sites in the Greater Accra Region, Ghana.

METHODS

Between 2010 and June 2013, recto-vaginal swab samples were collected from pregnant women attending antenatal care from two study sites in southern Ghana. The samples were collected within 35 and 37 weeks of the gestation period. These were inoculated into Todd-Hewitt broth followed by sub-culturing onto a sheep-blood agar plate. Identification was performed on a single subcultured colony. Gram staining was performed, and isolates were evaluated for beta-haemolytic reactions. Furthermore, the isolates were serotyped using the GBS latex serotyping kit.

RESULTS

The carriage rates were found to be 25.5% (95% CI: 19.6-32.1) to 28.0% (95% CI: 21.9-34.8) for the two collection sites. The most common serotypes were serotypes VII and IX. The data showed that women below 20 years of age or above 30 years of age have a significantly (p = 0.037) higher risk of carrying GBS compared to women from the age group of 20 to 30 years.

CONCLUSIONS

The findings of this study revealed that prevalence of GBS colonization in pregnant women in Greater Accra region is high and comparable to rates observed in South Africa and Western countries. The most prevalent serotypes were serotypes VII and IX, which have not been observed before in West Africa.

Evaluation of procedures for typing of group B Streptococcus: a retrospective study

Background

This study evaluates two procedures for typing of Streptococcus agalactiae (group B streptococci; GBS) isolates, using retrospective typing data from the period 2010 to 2014 with a commercial latex agglutination test (latex test) and the Lancefield precipitation test (LP test). Furthermore, the genotype distribution of phenotypically non-typable (NT) GBS isolates is presented. We also raise the awareness, that the difference in typing results obtained by phenotypical methods and genotype based methods may have implications on vaccine surveillance in case a GBS vaccine is introduced.

Methods

A total of 616 clinical GBS isolates from 2010 to 2014 were tested with both a latex test and the LP test. Among these, 66 isolates were genotyped by PCR, including 41 isolates that were phenotypically NT.

Results

The latex test provided a serotype for 83.8% of the isolates (95% CI [80.7–86.6]) compared to 87.5% (95% CI [84.6–90.0]) obtained by the LP method. The two assays provided identical capsular identification for all sero-typeable isolates (excluding NT isolates). The PCR assay provided a genotype designation to the 41 isolates defined as phenotypically NT isolates.

Discussion

We found that the latex test showed a slightly lower identification percentage than the LP test. Our recommendation is to use the latex agglutination as the routine primary assay for GBS surveillance, and then use the more labour intensive precipitation test on the NT isolates to increase the serotyping rate. A genotype could be assigned to all the phenotypically NT isolates, however, as a consequence genotyping will overestimate the coverage from possible future capsular polysaccharide based GBS vaccines.