Risk of preterm delivery in pregnant women with group B streptococcal urinary infections or urinary antibodies to group B streptococcal and E. coli antigens

Neonatal Group B Streptococcus Disease

Group B Streptococcus (GBS) is an important cause of neonatal sepsis in term and preterm infants. Because GBS colonizes human genitourinary and gastrointestinal tracts, a significant focus of neonatal GBS disease prevention is to interrupt vertical transmission of GBS from mother to infant during parturition. Routine antepartum GBS screening in pregnant women, as well as widespread use of intrapartum antibiotic prophylaxis, have aided in overall reductions in neonatal GBS disease during the past 3 decades. However, neonatal GBS disease persists and may cause mortality and significant short- and long-term morbidity among survivors. Herein, we highlight contemporary epidemiology, microbial pathogenesis, and the clinical presentation spectrum associated with neonatal GBS disease. We summarize obstetric recommendations for antenatal GBS screening, indications for intrapartum antibiotic prophylaxis, and considerations for antibiotic selection. Finally, we review national guidelines for risk assessment and management of infants at risk for GBS disease.

Examination of Complementary Medicine for Treating Urinary Tract Infections Among Pregnant Women and Children

Urinary tract infections (UTIs) are a significant clinical problem that pregnant women and children commonly experience. Escherichia coli is the primary causative organism, along with several other gram-negative and gram-positive bacteria. Antimicrobial drugs are commonly prescribed to treat UTIs in these patients. Conventional treatment can range from using broad-spectrum antimicrobial drugs for empirical or prophylactic therapy or patient-tailored therapy based on urinary cultures and sensitivity to prospective antibiotics. The ongoing emergence of multi-drug resistant pathogens has raised concerns related to commonly prescribed antimicrobial drugs such as those used routinely to treat UTIs. Consequently, several natural medicines have been explored as potential complementary therapies to improve health outcomes in patients with UTIs. This review discusses the effectiveness of commonly used natural products such as cranberry juice/extracts, ascorbic acid, hyaluronic acid, probiotics, and multi-component formulations intended to treat and prevent UTIs. The combination of natural products with prescribed antimicrobial treatments and use of formulations that contained high amounts of cranberry extracts appear to be most effective in preventing recurrent UTIs (RUTIs). The incorporation of natural products like cranberry, hyaluronic acid, ascorbic acid, probiotics, Canephron® N, and Cystenium II to conventional treatments of acute UTIs or as a prophylactic regimen for treatment RUTIs can benefit both pregnant women and children. Limited information is available on the safety of natural products in these patients' populations. However, based on limited historical information, these remedies appear to be safe and well-tolerated by patients.

Group B streptococci cultured in urine during pregnancy associated with preterm delivery: a selection problem?

Objective: To investigate an association between Group B streptococci (GBS) in urine culture during pregnancy and preterm delivery. Methods: A population-based cohort consisted of all the pregnant women (n = 36,097) from the catchment area of Lillebaelt Hospital, Denmark, during the period January 2002 -December 2012. The cohort of 34,285 singleton pregnancies used in this study was divided into three groups. Group I (N = 249) included women whose urine culture was positive for GBS; group II (N = 5765) included women whose urine culture was negative for GBS; and group III (N = 28 271) included women whose urine had not been cultured during pregnancy. Primary outcome was preterm delivery before 37 weeks' gestation (PTD). Results: We did not find an association between PTD and GBS bacteriuria in the cultured groups (odds ratios (OR) = 0.89; 95% CI: 0.5-1.4) ( Table 1 ). After controlling for potential confounders, the PTD remained not associated with GBS bacteriuria (adjusted OR = 0.99; 95% CI: 0.6-1.6). Combined, the cultured groups (I and II) were associated with a statistically significant higher risk for PTD, when compared with the group with no urine specimens taken for culture (OR = 1.96; 95% CI: 1.8-2.2 and adjusted or 1.80; 95% CI 1.6-2.0). The cultured group of women differed considerably from the group of women with no urine specimens taken for culture on the vast majority of variables examined. Conclusions: No association between asymptomatic GBS bacteriuria and preterm delivery among women with singleton pregnancy and urine specimens cultured during pregnancy was found. Previous suggestions of such association may have been compromised by a selection problem for testing due to a high-risk profile of pregnancy complications in pregnant women selected for urine culture.

Preterm Birth Associated With Group B Streptococcus Maternal Colonization Worldwide: Systematic Review and Meta-analyses

BACKGROUND

Preterm birth complications are the leading cause of deaths among children <5 years of age. Studies have suggested that group B Streptococcus (GBS) maternal rectovaginal colonization during pregnancy may be a risk factor for preterm delivery. This article is the fifth of 11 in a series. We aimed to assess the association between GBS maternal colonization and preterm birth in order to inform estimates of the burden of GBS.

METHODS

We conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus) and sought unpublished data from investigator groups on the association of preterm birth (<37 weeks' gestation) and maternal GBS colonization (GBS isolation from vaginal, cervical, and/or rectal swabs; with separate subanalysis on GBS bacteriuria). We did meta-analyses to derive pooled estimates of the risk and odds ratios (according to study design), with sensitivity analyses to investigate potential biases.

RESULTS

We identified 45 studies for inclusion. We estimated the risk ratio (RR) for preterm birth with maternal GBS colonization to be 1.21 (95% confidence interval [CI], .99-1.48; P = .061) in cohort and cross-sectional studies, and the odds ratio to be 1.85 (95% CI, 1.24-2.77; P = .003) in case-control studies. Preterm birth was associated with GBS bacteriuria in cohort studies (RR, 1.98 [95% CI, 1.45-2.69]; P < .001).

CONCLUSIONS

From this review, there is evidence to suggest that preterm birth is associated with maternal GBS colonization, especially where there is evidence of ascending infection (bacteriuria). Several biases reduce the chance of detecting an effect. Equally, however, results, including evidence for the association, may be due to confounding, which is rarely addressed in studies. Assessment of any effect on preterm delivery should be included in future maternal GBS vaccine trials.

An overview of the natural history of early onset group B streptococcal disease in the UK

Clinicians need information on the risk of Early Onset Group B Streptococcal disease (EOGBS) for counselling pregnant women and to decide who would benefit most from antibiotic treatment during labour. We carried out a systematic review of the research literature and conducted meta-analyses to obtain estimates for the natural history of EOGBS that are representative of the UK population. The mean rate of colonisation for the UK was 14% and we found weak evidence that the prevalence is increasing over time. Maternal GBS colonisation was more likely in women who delivered preterm compared with at term. Just over one-third of babies born to colonised mothers become colonised with GBS at birth (36%), and 3% of colonised babies develop EOGBS bacteraemia. In the UK, EOGBS constitutes one-third of all early onset bacteraemia due to pathogens, in contrast to one-half in the USA.

Group B Streptococcus carriers among HIV-1 infected pregnant women: Prevalence and risk factors

OBJECTIVE

The objective was to determine the frequency and risk factors of anogenital colonization by Streptococcus agalactiae (GBS) in pregnant women infected with human immunodeficiency virus type 1 (HIV-1).

STUDY DESIGN

A prospective study was conducted on 207 pregnant women divided into two groups: HIV group (n=101) and a control group consisting of HIV-uninfected pregnant women (n=106) to assess regional colonization by GBS. Anal and vaginal swabs were collected and cultured in Todd-Hewitt broth, followed by a confirmatory test. For a control group with an anticipated proportion based on literature research of 10-30% and alpha=0.05, a sample size of 100 would have a power of 80% to detect a difference of 15% or greater with a study group. The mothers were studied in terms of frequency of anogenital colonization by GBS, maternal epidemiological data, and TCD4 lymphocyte counts. The results were analyzed using the chi(2)-test, Fisher's exact test and the Student's t-test, with the level of significance set at p<0.05.

RESULTS

Twenty (19.8%) HIV-1-infected pregnant women were found to be colonized by GBS at between 35 and 37 weeks' gestation. In the control group, the prevalence of GBS was 14.1%.

CONCLUSION

No significant increase in GBS colonization was observed in HIV-1-infected pregnant women. Maternal colonization of GBS in HIV-infected pregnant women was not found to be associated with their immunological status. Sexual contact does not seem to be the principal way of transmitting GBS.

Incidence of and socio-demographic risk factors for stillbirth, preterm birth and low birthweight among Zimbabwean women

Data on birth outcomes are important for planning maternal and child health care services in developing countries. Only a few studies have examined frequency of birth outcomes in Zimbabwe, none of which has jointly examined the spectrum of poor birth outcomes across important demographic subgroups. We assessed delivery patterns and birth outcomes in 17 174 births over a one-year period from October 1997 to September 1998 at Harare Hospital, Zimbabwe. The annual rate of stillbirth was 61 per 1000 live births, rate of preterm birth (<37 weeks) was 168 per 1000, and low birthweight (LBW) (<2500 g) was 199 per 1000. Not attending antenatal care (prenatal care) was associated with increased risks of stillbirth [relative risk (RR) = 2.54, 95% CI 2.21, 2.92], preterm delivery [RR = 2.43, 95% CI 2.26, 2.61] and LBW births [RR = 2.16, 95% CI 2.02, 2.31]. Preterm births and LBW births were more likely to be stillborn [RR = 7.26, 95% CI 6.28, 8.39 and RR = 6.85, 95% CI 5.94, 7.91]. In conclusion, the rate of stillbirth is high and is predominantly associated with preterm births and to a lesser extent LBW. Reducing the frequency of stillbirth will require a better understanding of the determinants of preterm births and strategies for addressing this particular subset of high-risk births.

Infections in international pregnancy study: performance of the optical immunoassay test for detection of group B streptococcus

We evaluated the Strep B optical immunoassay (OIA; ThermoBiostar, Inc.) for detecting light and heavy group B streptococcus colonization in 1,306 pregnant women. The women were examined at 20 to 32 weeks gestation and were from six countries. Compared to culture, the sensitivity and specificity of OIA were 13.3 and 98.4%, respectively, for light colonization and 41.5 and 97.7%, respectively, for heavy colonization.

Is antenatal group B streptococcal carriage a predictor of adverse obstetric outcome?

OBJECTIVES

While early-onset neonatal GBS sepsis is positively associated with premature birth and prolonged rupture of membranes, there is debate in the literature as to whether maternal GBS colonization is a predictor of adverse obstetric outcome. This is a critical issue to resolve for appropriate management (expectant vs. interventional management) of the patient presenting with premature rupture of membranes, who has no overt signs of sepsis, but who is colonized with GBS.

METHODS

Since 1981 it has been hospital policy to screen all public patients antenatally for genital carriage of GBS by collection of a low vaginal swab at 28-32 weeks. All patients colonized with GBS antenatally are given penicillin as intrapartum chemoprophylaxis. Review of all GBS-colonized antenatal patients for a 12-month period (580 of 4,495 patients) and a randomized (every fourth consecutive antenatal patient) number of noncolonized patients (958) was made. Lower vaginal GBS colonization and other risk factors for preterm delivery were assessed using univariate and multivariate generalized linear modeling.

RESULTS

In the study group, the maternal GBS colonization rate was 12.9%. When cofounding variables were controlled in a multivariate analysis, the association between antepartum GBS colonization and preterm labor and preterm rupture of membranes was not significant.

CONCLUSION

Maternal antenatal carriage of GBS does not predict preterm labor. Therefore it is appropriate that expectant management occur for a GBS-colonized woman who ruptures her membranes, is not in labor, and has no evidence of sepsis.

Group B streptococcus

During the 1990s the focus of group B streptococcus (GBS) disease research has shifted to prevention. Increased use of intrapartum antimicrobial prophylaxis in North America and Australia has led to substantial declines in perinatal disease. Vaccine development (initiated two decades earlier) has yielded results--for example, polysaccharide-protein conjugate vaccines given to women of reproductive age proved to be highly immunogenic and well tolerated. Also economic evaluations have assessed the cost-effectiveness of prevention strategies in different populations. Although GBS has traditionally been considered a perinatal pathogen, the burden of invasive GBS disease among nonpregnant adults has been measured. Adverse outcomes of pregnancy attributable to GBS were addressed through a multicentre study which confirmed the important role of heavy colonisation with GBS in preterm low-birthweight deliveries. Finally, the pathogen itself has continued to evolve: new capsular serotypes described in the past decade are now causing an important proportion of clinical infections.

Group B streptococcal infections

Group B streptococcal infection is the most common cause of neonatal sepsis and is responsible for significant neonatal morbidity and mortality. Group B streptococcus is also the causative agent in 50,000 maternal infections per year. Approximately 30% of women have asymptomatic group B streptococcal colonization at some time during pregnancy, but the neonatal attack rate is only about 2 per 1,000 deliveries. Maternal and neonatal risk factors contribute to the rates of vertical transmission and symptomatic neonatal disease. Options that have been investigated for prevention of neonatal group B streptococcal disease include identification of at-risk pregnancies as well as antenatal, intrapartum, and neonatal treatment. The intrapartum treatment of women at risk for vertical transmission of group B streptococcus to their neonates unequivocally has been shown to decrease the rate of neonatal colonization. Practitioners should implement one of two strategies that incorporate intrapartum prophylaxis for prevention of perinatal group B disease.

The effects of Escherichia coli STa (heat stable) toxin on the contractility of isolated human myometrium in vitro

OBJECTIVE

The purpose of the study was to assess the effects of Escherichia coli STa (heat stable) toxin on isolated human myometrial response to oxytocin.

METHODS

One hundred and sixteen muscle strips were obtained from the lower uterine segment of 42 women undergoing cesarean section at term. Amniotic membranes and decidua were excluded. Uterine contractility in response to cumulative doses of E. coli STa toxin was recorded, as well as uterine response to cumulative doses of oxytocin before and after incubation with STa toxin or vehicle. The 50th percentile effective oxytocin concentration (EC50) of muscle strips with and without spontaneous activity before and after the incubation with STa toxin or vehicle was calculated. A paired t test was used for comparison.

RESULTS

Muscle strips with and without spontaneous activity responded to cumulative doses of oxytocin before and after the incubation with STa toxin or vehicle. No differences in contraction force, duration, or frequency were noted between the groups (P > 0.05). Furthermore, this toxin was not able to induce uterine contractility when tested alone.

CONCLUSIONS

The inability of this toxin to affect myometrial response to oxytocin in this study may be due to the absence of amnion cells, chorion, or decidua. Other possible explanations for the lack of response are discussed.

Urinary tract infection during pregnancy: a risk factor for cerebral palsy?

OBJECTIVE

To assess a possible association of urinary tract infection (UTI) during pregnancy and cerebral palsy in offspring.

DESIGN

Secondary analysis of a case-control study using structured telephone interviews and birth certificate reviews.

SETTING

Cases from community-based agencies providing services to preschool children who were developmentally delayed.

PARTICIPANTS

One hundred twelve preschool children with cerebral palsy and 153 children without cerebral palsy.

MAIN OUTCOME MEASURES

Risk for cerebral palsy.

RESULTS

The prevalence of UTI among case mothers was 17.9% compared with 5.2% among control mothers. The crude odds ratio for risk of cerebral palsy for a mother with a UTI was 3.9, whereas the adjusted odds ratio was approximately 5, indicating that the risk of having a child with cerebral palsy was 4 to 5 times greater for mothers who had a UTI during pregnancy.

CONCLUSIONS

Urinary tract infection during pregnancy was found to be a risk factor for development of cerebral palsy in offspring. Assessment for UTI should occur at the initial prenatal visit and more frequently for women with symptoms or who are at risk. Pregnant women should be educated about preventive measures for UTI. Future research is needed to assess more directly the relationship between UTI during pregnancy and cerebral palsy in offspring.

Antibiotic therapy for preterm premature rupture of the membranes

Amniotic fluid studies and placental histopathological evaluation have confirmed the association between intrauterine infection and preterm premature rupture of the membranes (pPROM). This association is increasingly strong with pPROM at early gestational ages. The organisms associated with pPROM include a broad spectrum of aerobic and anaerobic gram-positive and gram-negative bacteria. In many cases, the patient presenting with pPROM will have overt intrauterine infection necessitating delivery. For those amenable to expectant management, the clinical course is usually of brief latency between membrane rupture and delivery. A number of well-designed prospective clinical trials have evaluated the utility of antibiotic treatment during the expectant management of pPROM. Taken together, these studies suggest broad spectrum antibiotic treatment of this population to enhance pregnancy prolongation, and to reduce maternal and neonatal infectious morbidity. There are some data suggesting the potential for a reduction in neonatal gestational age-dependent morbidity. We recommend aggressive adjunctive antibiotic treatment to prolong pregnancy and reduce morbidity in patients with pPROM, at gestations remote from term, when a significant improvement in neonatal outcome can anticipated with expectant management.

The pathobiology of premature rupture of membranes

Premature rupture of membranes arises from what are likely multifaceted and multistep pathogenic pathways. Pathophysiological processes may involve both endogenous and exogenous fetal and maternal factors. This article reviews and analyzes information regarding, first, the form and function of fetal membranes; second, how membranes physically fail (rupture) at term and preterm gestations; and third, evaluates if we can reduce risks of rupture using physiological understanding and evidence-based clinical studies.

Colonization with group B streptococci in pregnancy and adverse outcome. VIP Study Group

OBJECTIVE

Our purpose was to study the association of cervicovaginal colonization with group B streptococci with pregnancy and neonatal outcome.

STUDY DESIGN

A prospective study was conducted at seven medical centers between 1984 and 1989. Genital tract cultures were obtained at 23 to 26 weeks' gestation and at delivery. Prematurity and neonatal sepsis rates were compared between group B streptococci positive and negative women.

RESULTS

Group B streptococci was recovered from 2877 (21%) of 13,646 women at enrollment. Heavy colonization was associated with a significant risk of delivering a preterm infant who had a low birth weight (odds ratio = 1.5, 95% confidence interval 1.1 to 1.9). Heavily colonized women given antibiotics effective against group B streptococci had little increased risk of a preterm, low-birth-weight birth. Women with light colonization were at the same risk of adverse outcome as the uncolonized women. Neonatal group B streptococci sepsis occurred in 2.6 of 1000 live births in women with and 1.6 of 1000 live births in women without group B streptococci at 23 to 26 weeks' gestation (p = 0.11). However, sepsis occurred in 16 of 1000 live births to women with and 0.4 of 1000 live births to women without group B streptococci at delivery (p < 0.001).

CONCLUSIONS

Heavy group B streptococci colonization of 23 to 26 weeks' gestation was associated with an increased risk of delivering a preterm, low-birth-weight infant. Cervicovaginal colonization with group B streptococci at 23 to 26 weeks' gestation was not a reliable predictor of neonatal group B streptococci sepsis. Colonization at delivery was associated with sepsis.

Group B streptococcus and pregnancy

Group B streptococcus is a significant pathogen for both mother and child. routine urine culture in pregnancy will identify and allow treatment of women with asymptomatic bacteriuria. An optimal protocol for the prevention of neonatal sepsis has not yet been developed. While intrapartum antimicrobial prophylaxis appears to provide the best potential, each of the currently suggested protocols has significant drawbacks. Drawbacks include the potential for missing high-risk carriers, failure to treat a significant proportion of those destined to deliver an affected infant because no risk factors are present, and empirical treatment of a large proportion of the population in order to present significant disease in a few. Until an effective program of immunization becomes available, intrapartum prophylaxis of group B streptococcal carriers appears to offer the best hope of reducing the incidence of neonatal disease. Caregivers should adopt a uniform practice with regard to screening and prophylaxis. It is essential that any broad-based screening program include an evaluation of efficacy as well as complications including the development of new etiologic agents as causes of neonatal sepsis and the emergence of resistant bacteria. Further, mothers and newborns should be evaluated for drug adverse reactions and the impact of intrapartum prophylaxis on the use of prolonged empirical broad-spectrum antimicrobial therapy on the asymptomatic infant. Additional research is necessary regarding the required duration of therapy for optimal effect of intrapartum prophylaxis, the need for postnatal prophylaxis of the asymptomatic neonate, and the optimal agent for neonatal prophylaxis (penicillin versus broad-spectrum agents) if neonatal therapy is necessary after intrapartum prophylaxis.

Prevention of preterm birth

Preterm labour and delivery remain a major cause of perinatal morbidity, mortality and long-term adverse neurodevelopmental outcome. An effective primary prevention strategy is desirable, but current approaches appear largely ineffective at present. Understanding the aetiology of the onset of preterm labour continues to improve with the recognition of the role played by subclinical infection in a significant proportion of cases. The investigation of hormonal influences in the aetiology of preterm labour is at an early stage, but there appears to be a relationship between raised serum relaxin concentrations and preterm delivery (Petersen et al, 1992). The naturally occurring phospholipase A2-inhibitor gravidin, believed to be important in pregnancy maintenance, is found in a reduced concentration in women delivering preterm (Wilson, 1993). The relationship between hormonal levels, socio-economic influences, subclinical infection and actual preterm labour and delivery remains to be established. Secondary prevention with tocolysis remains unsatisfactory, owing to the low therapeutic index of currently available agents and their varied maternal and neonatal adverse effects. The investigation of newer tocolytic agents remains a worthwhile pursuit, whilst the underlying aetiology of preterm labour and effective prevention remains to be elucidated. The widespread recognition of the benefits of antenatal corticosteroid administration and subsequent adoption into clinical practice has reduced, and will continue to reduce, the morbidity associated with preterm birth while newer methods of accelerating fetal maturation are explored and applied in clinical practice.