Risk-based approach versus culture-based screening for identification of group B streptococci among women in labor

Maternal age and body mass index as risk factors for rectovaginal colonization with group B streptococci

OBJECTIVE

To examine the effect of including maternal age and body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) as additional risk factors in the traditional risk-based strategy at term pregnancies consisting of previous early-onset group B streptococcus (GBS) disease, GBS bacteriuria during pregnancy, maternal temperature of 38.0°C or more intrapartum, and rupture of membranes of 18 h or longer.

METHODS

A secondary analysis of a Danish cohort including 902 pregnant women. Exposures were maternal age and pre-pregnancy BMI. Outcome was rectovaginal GBS colonization at the time of labor. The logistic regression analysis adjusted for parity, gestational age, vaginal delivery, and smoking.

RESULTS

The GBS prevalence was 17% in the entire population, 35% among participants older than 40 years, and 23% among those with a BMI of 25 or greater. Including maternal "age > 40" as an additional risk factor increased the sensitivity of the risk-based strategy from 21% to 26% and decreased the specificity from 90% to 87%. Inclusion of "BMI ≥ 25" increased the sensitivity from 21% to 57% and decreased the specificity from 90% to 59%.

CONCLUSIONS

Maternal age and BMI might be included as additional risk factors in risk-based programs for identification of GBS-positive laboring women to receive intrapartum antibiotics prophylaxis.

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.

The serotype distribution of Streptococcus agalactiae (GBS) carriage isolates among pregnant women having risk factors for early-onset GBS disease: a comparative study with GBS causing invasive infections during the same period in Denmark

Background

We describe the serotype distribution of Streptococcus agalactiae (GBS) carriage isolates from women in labor and among GBS isolates causing invasive infections during the same period to see if the distribution of carriage serotypes reflects the GBS serotypes causing invasive diseases including early-onset disease (EOGBS).

Methods

Data on invasive isolates from 2019 including serotype, erythromycin and clindamycin susceptibility was retrieved from the Danish national reference laboratory, Statens Serum Institut. Carriage isolates were collected from women with risk factors for EOGBS enrolled at delivery at the maternity ward at a Danish University Hospital, first half of 2019.

Results

Among carriage isolates, the dominant serotype was IX (21 %) followed by serotype III (19 %). The resistance to erythromycin and clindamycin was 21 and 26 %, respectively. Among invasive GBS isolates, no case of EOGBS with serotype IX was detected but the distribution of serotypes were otherwise similar to the GBS carrier strains. The corresponding resistance to erythromycin and clindamycin was 23  and 15 %, respectively. Penicillin resistance was not detected among carriage nor invasive isolates.

Conclusions

The distribution of serotypes among carriage and invasive GBS reflects the assumption that EOGBS occur following transmission of GBS from mother to newborn, with the exception of serotype IX.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06820-2.

Clinical Profile and Outcome of Group B Streptococcal Colonization in Mothers and Neonates in Ras Al Khaimah, United Arab Emirates: A Prospective Observational Study

Background:

Maternal Group B Streptococcus (GBS)/Streptococcus agalactiae colonization rates vary worldwide; however, no such recent data are available from the United Arab Emirates (UAE).

Objective:

The objective of this study was to determine the prevalence of GBS colonization among pregnant women attending an antenatal clinic of a hospital in Ras Al Khaimah, UAE, along with the antibiotic sensitivity pattern, the clinical profile and pregnancy (maternal and fetal) outcome.

Methods:

This prospective observational study routinely offered rectovaginal swab for GBS to all women attending the antenatal clinic at 35–37 weeks of pregnancy between January and December 2019. MASTASTREP kit and Vitek-2 identification system was used for culture and identification. Women with positive cultures were followed up for any maternal and neonatal complications and the use of intrapartum antibiotic prophylaxis (IAP).

Results:

A total of 2295 women were included, of which 158 (6.9%) had positive cultures for GBS colonization. The carriage rate was higher in women without any risk factors for early-onset GBS disease (EOGBS) (P < 0.01). The GBS isolates were about 97% susceptible to linezolid and vancomycin, 90% to benzyl penicillin and 95% to ampicillin. Resistance to trimethoprim/sulfamethoxazole, clindamycin, erythromycin, and levofloxacin were about 77%, 57%, 57%, and 10%, respectively. Urinary tract infection in GBS colonized women were more common in those aged ≤30 years (P = 0.009). Fetal outcome was favorable in women receiving IAP for GBS colonization. No neonate had culture proven EOGBS.

Conclusion:

The prevalence of GBS colonization in pregnant women as well as the overall maternal and neonatal complications is low in Ras Al Khaimah, UAE. IAP is effective in preventing early-onset sepsis in newborn, and thus should be initiated in those with GBS colonization. The cultured GBS showed sensitivity to most antibiotics.

Group B streptococcal infections in infants in Iceland: clinical and microbiological factors

Introduction. Group B streptococcus (GBS) is a leading cause of invasive neonatal infections. These have been divided into early-onset disease (EOD; <7 days) and late-onset disease (LOD; 7-89 days), with different GBS clonal complexes (CCs) associated with different disease presentations.Hypothesis. Different GBS CCs are associated with timing of infection (EOD or LOD) and clinical presentation (sepsis, meningitis or pneumonia).Aim. To study infant GBS infections in Iceland from 1975 to 2019. Are specific GBS CCs related to disease presentation? Is CC17 overrepresented in infant GBS infections in Iceland?Methodology. All culture-confirmed invasive GBS infections in infants (<90 days) in Iceland from 1975 to 2019 were included. Clinical information was gathered from medical records.Results. A total of 127 invasive GBS infections in infants were diagnosed, but 105 infants were included in the study. Of these, 56 had EOD and 49 had LOD. The incidence of GBS infections declined from 2000 onwards but increased again at the end of the study period. Furthermore, there was a significant increase in LOD over the study period (P=0.0001). The most common presenting symptoms were respiratory difficulties and fever and the most common presentation was sepsis alone. Approximately one-third of the cases were caused by GBS CC17 of serotype III with surface protein RIB and pili PI-1+PI-2b or PI-2b. CC17 was significantly associated with LOD (P<0.001).Conclusion. CC17 is a major cause of GBS infection in infants in Iceland. This clone is associated with LOD, which has been increasing in incidence. Because intrapartum antibiotic prophylaxis only prevents EOD, it is important to continue the development of a GBS vaccine in order to prevent LOD infections.

Group B Streptococcus Screening Guidelines in Pregnancy: A Critical Review of Compliance

INTRODUCTION

Colonization with Group B Streptococcus in pregnancy is a major risk factor for neonatal infection. Universal screening for maternal streptococcal colonization and the use of intrapartum antibiotic prophylaxis has resulted in substantial reductions of neonatal early-onset Group B Streptococcus disease. To achieve the best neonatal outcomes, it is imperative for maternity healthcare providers to adhere to screening and management guidelines.

AIM

This literature review uses a systematic approach and aims to provide a synthesis of what is known about compliance with Group B Streptococcus screening protocols in a variety of global settings, including maternity homes, private obstetric practice, and hospital clinical environments.

METHODS

The review was carried out using electronic databases as well as hand-searching of reference lists. Included papers reported primarily on compliance with Group B Streptococcus screening guidelines, potential factors which influence compliance rates, and implementations and outcomes of interventions.

RESULTS

Six international studies have been retained which all focused on adherence to Group B Streptococcus screening guidelines and demonstrated that different factors might have an influence on adherence to GBS screening protocols such as financial aspects and high caesarean section rates. Findings of relatively low compliance rates led to recognizing the need of developing improved strategies for optimising antenatal GBS screening adherence.

CONCLUSION

Adhering to Group B Streptococcus screening guidelines to prevent neonatal infection is crucial. Various factors influence compliance rates such as financial aspects and high proportions of caesarean sections. The implementation of strategies and different forms of education can result in improved compliance rates.

Group B Streptococcus in Indian pregnant women: Its prevalence and risk factors

Purpose

To study the prevalence of group B streptococci (GBS) in Indian pregnant women and associated risk factors.

Methods

Four hundred and fifty pregnant women attending antenatal outpatient/inpatient department between 35-38 weeks of gestation were enrolled in the study. All enrolled subjects were assessed by a predefined proforma for their demographics, socio-economic characteristics, education, toilet habits, obstetric history and clinical outcome. Two cotton swabs each from lower vagina and rectum were collected and plated on selective solid media CHROM agar Strept B (CHROMagarTM) and selective Enrichment Broth LIM RambaQUICK StreptB broth (CHROMagarTM). Presumptive identification of GBS was growth of 1-3 mm grayish white β-hemolytic colonies on BAP or mauve coloured colonies on CHROM agar Strept B. All presumptively identified GBS were confirmed as group B streptococcus by automated identification system-Vitek MS (Bio Merieux).

Results

The recto vaginal colonization rate of GBS in this study was observed as 3.3% (n=15). GBS colonization was significantly associated with nulliparous women (p= 0.026) and use of western style toilet (p=0.017). GBS urinary tract infections was also seen more commonly in women with GBS rectovaginal colonization (p=0.002).

Conclusion

Due to the low GBS prevalence and no significant association with major risk factors, we recommend to institute universal screening of GBS in pregnant women, instead of risk based screening. Since this was a single centric study with low prevalence of GBS, its applicability may be limited, therefore further larger multi-centric prospective studies are required to understand the true GBS prevalence in Indian society.