Risk factors for maternal colonization with group B beta-hemolytic streptococci

Prevalence and Risk Factors of Group B Streptococcus Colonization in Pregnant Women: A Pilot Study in Palestine

Background

Maternal Streptococcus agalactiae (Group B Streptococcus (GBS)) colonization is an important cause of complications in mothers and neonates during gestation and after delivery. The data regarding GBS colonization among pregnant women in Palestine is scarce. The aim of this study is to determine the prevalence of GBS colonization, its associated risk factors, and the antibiotic sensitivity patterns in Nablus, West Bank, Palestine.

Methods

A cross-sectional, single center study conducted at Rafidia Governmental Hospital in Nablus, West Bank, Palestine. Samples were collected between November 2019 and January 2020. Vaginal swabs from 200 pregnant women (≥35 weeks of gestation) attending the labor and delivery department were plated directly on CHROMagar^TM StrepB (CHROM agar, France) and placed in an incubator at 35–37°C. After 24 and 48 hours, the plates were checked for growth and classified into three categories: growth of GBS with mauve colonies on chromogenic media, no growth, or other growth. The identification of the mauve colonies was confirmed by the CAMP test. Identified GBS isolates were tested for susceptibility to vancomycin, ampicillin, clindamycin, cefotaxime, erythromycin, and levofloxacin using the disc diffusion method. Clinical and demographic information were collected using a questionnaire.

Result

The overall prevalence of GBS colonization was 12%. The median age of the study population was 27 years. GBS colonization was significantly associated with age (p=0.013), history of previous preterm delivery (p=0.013), and parity (p=0.015). No association was noted with smoking, previous abortion, previous history of fetal demise, vaginitis, or urinary tract infection. Resistance to ampicillin, vancomycin, cefotaxime, erythromycin, clindamycin, and levofloxacin was found to be 91.7%, 54.2%, 45.8%, 29.2%, 25%, and 8.3%, respectively.

Conclusion

The prevalence of vaginal GBS in this study was 12% from Nablus, West Bank. Further research is needed to determine the GBS serotypes common in West Bank and the burden they cause on the health system. Moreover, this study also highlights the need to establish a screening program suited to a developing country with low control on the antibiotic's prescription protocols.

Group B streptococcal colonization: Prevalence and impact of smoking in women delivering term or near term neonates in a large tertiary care hospital in the southern United States

Background and hypothesis

The role of smoking as a risk factor for group B streptococcal (GBS) colonization in women during pregnancy has not been previously adequately explored. We hypothesized that women of term or near term neonates who smoked during pregnancy were more likely to have GBS colonization than their non-smoking counterparts.

Methods

The electronic health records (EHRs) of a convenience sample of women delivering in an inner-city university tertiary care center were reviewed. The outcome variable of interest was maternal GBS colonization during pregnancy. The primary independent variable of interest was tobacco smoking during pregnancy, determined from the EHRs by the number of cigarettes smoked during gestation. Descriptive statistics were conducted and categorical data were compared by the Fischer’s exact test. Multiple logistic regression analysis was further conducted to determine the independent impact of tobacco smoke exposure on GBS colonization.

Results

The prevalence of maternal GBS colonization was 35% among the study population. In the univariate analyses, factors associated with maternal GBS colonization were tobacco smoking during pregnancy (P of trend <0.001), Race (P<0.001), maternal age <20 years (P = 0.006), low birthweight <2500 gm (P = 0.020), maternal drug use (P = 004), and gestational age <37 (P = 0.041). In a multiple logistic regression analysis, tobacco smoking during pregnancy remained the most significant predictor of GBS colonization. Women who smoked during pregnancy were more than twice more likely to be colonized than their non-smoking counterparts (OR = 2.6; 95% CI = 1.5–4.6; p<0.001). Maternal age was the only other significant predictor with younger mothers more than one and a half time more likely to be colonized than their older counterparts (OR = 1.65; 95% CI = 1.02–2.68; P = 0.04).

Conclusion

The prevalence of GBS colonization in this institution was consistent with recent national rates. Smoking and maternal age were identified as two independent risk factors for GBS colonization during pregnancy. Further studies are needed to confirm these findings.

Prevalence and risk factors of group B Streptococcus colonisation in intrapartum women: a cross-sectional study

A cross-sectional study was conducted at a Thai university hospital between November 2016 and March 2017 to evaluate the prevalence and risk factors of group B Streptococcus (GBS) colonisation in pregnant women who were admitted to the labour room for delivery. Rectovaginal specimens were collected and processed for the identification of GBS. Univariate and multiple logistic regression analyses were conducted to evaluate factors associated with GBS colonisation. Statistical significance was set at p < .05. Fifty-seven of 505 pregnant women (11.3%, 95% confidence interval [CI] 9.0-15.0%) were found to have GBS colonisation. Teenage pregnancy (odds ratio [OR] 3.83, 95% CI 1.13-13.02, p < .05), multi-parity (OR 3.59, 95% CI 1.69-7.60, p < .01) and non-Buddhist religions (OR 1.87, 95% CI 1.01-3.48, p < .05) were significantly associated with GBS colonisation. Intrapartum risk factors were not associated with GBS colonisation. Impact statement What is already known on this subject? The prevalence of GBS colonisation in pregnant women varies by geographic areas and ethnicities, ranging from 2.3 to 32.9%. Risk factors for GBS colonisation have been studied but the results were inconsistent. What do the results of this study add? This study reports the prevalence of GBS colonisation in intrapartum women in Southern Thailand to be 11.3%. We also identified some independent risk factors for GBS colonisation which were teenage pregnancy, multi-parity and non-Buddhist religions. To our knowledge, the relationship between religious belief and identification of GBS has never been reported before. We also found that intrapartum risk factors that have been used as the indication for intrapartum antibiotics administration have no correlation with GBS colonisation. What are the implications of these findings for clinical practice and/or further research? This study adds to the literature the prevalence and risk factors of GBS colonisation in the setting of a developing country. It also shows that intrapartum risk identification alone is not an optimal strategy to reduce infection associated with GBS. Instead, prenatal GBS screening should be encouraged to identify women with GBS colonisation to reduce the risk of infection and unnecessary antibiotics exposure.

Prevalence, antimicrobial resistance and serotype distribution of group B streptococcus isolated among pregnant women and newborns in Rabat, Morocco

Purpose. Group B streptococcus (GBS) is an important cause of neonatal sepsis worldwide. Data on the prevalence of maternal GBS colonization, risk factors for carriage, antibiotic susceptibility and circulating serotypes are necessary to tailor adequate locally relevant public health policies.Methodology. A prospective study including pregnant women and their newborns was conducted between March and July 2013 in Morocco. We collected clinical data and vagino-rectal and urine samples from the recruited pregnant women, together with the clinical characteristics of, and body surface samples from, their newborns. Additionally, the first three newborns admitted every day with suspected invasive infection were recruited for a thorough screening for neonatal sepsis. Serotypes were characterized by molecular testing.Results. A total of 350 pregnant women and 139 of their newborns were recruited. The prevalence of pregnant women colonized by GBS was 24 %. In 5/160 additional sick newborns recruited with suspected sepsis, the blood cultures were positive for GBS. Gestational hypertension and vaginal pruritus were significantly associated with a vagino-rectal GBS colonization in univariate analyses. All of the strains were susceptible to penicillin, while 7 % were resistant to clindamycin and 12 % were resistant to erythromycin. The most common GBS serotypes detected included V, II and III.Conclusion. In Morocco, maternal GBS colonization is high. Penicillin can continue to be the cornerstone of intrapartum antibiotic prophylaxis. A pentavalent GBS vaccine (Ia, Ib, II, III and V) would have been effective against the majority of the colonizing cases in this setting, but a trivalent one (Ia, Ib and III) would only prevent 28 % of the cases.

Modified use of real-time PCR detection of group B Streptococcus in pregnancy

The CDC recommends antenatal screening of vaginal/rectal samples for Streptococcus agalactiae at 35-37 weeks' gestation, with intra-partum antibiotic prophylaxis for positive cases. We tested a modified use of the Cepheid Xpert GBS real-time PCR kit on enrichment cultures from 554 vaginal/rectal swabs compared to the current subculturing gold standard method. Swabs were inoculated on polymyxin nalidixic acid agar plates, and Todd-Hewitt enrichment broth cultures were examined daily for growth. Todd-Hewitt broth culture was also used for Xpert GBS. There was 92.06 % agreement between the subculture and PCR methods. Sensitivity of Xpert GBS was 100 %, specificity was 89.40 %, positive predictive value was 75.96 % and negative predictive value was 100 %. Colonization incidence was higher with younger (≤24 years) or older (≥35 years) maternal age. Modified use of the Cepheid Xpert GBS would assist rapid diagnosis of S. agalactiae colonization and facilitate timely and appropriate assignment to intra-partum antibiotic prophylaxis.

Group B Streptococcus colonization by HIV status in pregnant women: prevalence and risk factors

OBJECTIVES

To examine the prevalence of and risk factors for group B Streptococcus (GBS) colonization in an HIV-infected and uninfected pregnant population.

METHODS

We conducted a retrospective double cohort study comparing the prevalence of GBS colonization between 90 HIV-infected and 1947 uninfected women attending prenatal care at San Francisco General Hospital, an urban public hospital affiliated with the University of California, San Francisco. We investigated risk factors for GBS colonization, including age, ethnicity, obesity, diabetes, alcohol or illicit drug use, tobacco use, degree of immunosuppression, and infectious comorbidities.

RESULTS

In the multivariable analysis, HIV serostatus was not independently associated with GBS colonization (odds ratio [OR] 1.00, 95% confidence interval [CI] 0.62-1.62). Obesity (OR 1.53, 95% CI 1.13-2.07), white race (OR 1.89, 95% CI 1.30-2.75), and black race (OR 1.78, 95% CI 1.32-2.41) were independently associated with increased maternal GBS colonization. Among HIV-infected women, univariate analysis showed an association between GBS colonization and detectable HIV-1 plasma viral load at the time of rectovaginal culture (p<0.05). Mean CD4 lymphocyte count, infectious comorbidities, and HIV-1 plasma viral load at delivery were not associated with GBS colonization in HIV-infected pregnant women.

CONCLUSIONS

HIV-1 infection is not a risk factor for GBS colonization among an ethnically diverse pregnant population at San Francisco General Hospital, although our data suggest that among HIV-infected women, plasma HIV-1 viremia may be associated with GBS colonization. Interventions that diminish HIV-1 plasma viral load and, perhaps, genital tract shedding of HIV may be associated with a reduced risk of GBS colonization in future studies.

Maternal smoking during pregnancy increases the risk of postnatal infections in preterm neonates

BACKGROUND

Maternal smoking during pregnancy is known to be associated with perinatal complications such as preterm delivery, low birth weight, and sudden infant death syndrome.

OBJECTIVE

The purpose of this study was to evaluate the influence of smoking during pregnancy on the risk of postnatal infections in preterm neonates.

METHOD

We examined 80 preterm infants (gestational age 24-36 weeks), of whom 40% had been exposed to tobacco smoking during pregnancy.

RESULTS

Infections occurred in 31 infants. Gestational age and maternal smoking had a significant effect on the occurrence of infections (p < 0.001 and p = 0.015, respectively). An increase in maternal tobacco consumption by 10 cigarettes/day showed an odds ratio of 2.7 (95% confidence interval 1.1-6.4) for occurrence of infections.

CONCLUSIONS

A significant association between maternal use of tobacco and the occurrence of infections in preterm neonates was found. Thus, campaigns about the damaging effects of tobacco are still warranted.

The effects of prenatal exposure of mice to cigarette smoke on offspring immune parameters

While direct exposure to cigarette smoke (CS) was shown in numerous human and animal studies to impair host immune responses, effects on the offspring following in utero CS exposure are relatively unknown. Thus, a toxicological study was performed that extended our previous investigations examining the effects of relatively low-dose CS exposure on immune tumor surveillance parameters of the prenatally exposed offspring. In the current study, pregnant B6C3F1 mice were exposed by inhalation to mainstream CS (at a concentration equivalent to smoking approximately 1 pack of cigarettes/d) for 5 d/wk, 4 h/d from gestational day 4 to parturition. Smoke-induced effects on a number of immune parameters were examined in 3- (and/or 5-), 10-, and 20-wk-old male and female offspring, including lymphoid organ weight/cellularity; blood and bronchopulmonary lavage cell numbers/profiles; splenic lymphocyte proliferation; mixed lymphocyte reactions; and, host resistance against transplanted melanoma cells. Exposure in utero to CS significantly increased circulating white blood cell and lymphocyte numbers in both sexes for up to 2.5 mo after birth (compared to their age-/sex-matched, air-exposed counterparts). In addition, 3-wk-old male and female offspring from smoke-exposed mothers had decreased mitogen-stimulated T-lymphocyte proliferation, while 5-wk-old male pups had increased mixed lymphocyte response compared to their sex-matched, air-exposed counterparts. Although effects of prenatal smoke exposure on overall offspring immunity were relatively modest, these findings could suggest that early toxic insult by CS may alter subsequent immune homeostasis in the offspring, leading, possibly, to changes in disease vulnerability.

Impact and risk factors for early-onset group B streptococcal morbidity: analysis of a national, population-based cohort in Sweden 1997-2001

OBJECTIVES

To study early-onset group B streptococcal (EOGBS) morbidity, mortality, and maternal risk factors.

DESIGN

Observational, population-based, retrospective. Data from national registers and medical records.

SETTING

Sweden, 1997-2001.

POPULATION

Cohort of 640 infants with a diagnosis of GBS infection out of 435 070 live births.

METHOD

Infants with diagnoses GBS sepsis (P36.0) and/or pneumonia (P23.3) were analysed. In cases with P36.0, register data were validated against infant and maternal medical records. Odds ratios (OR) were estimated by multiple logistic regression.

MAIN OUTCOME MEASURES

Incidence of EOGBS morbidity, mortality, frequency of maternal risk factors and administration of intrapartum antibiotics.

RESULTS

There were 319 cases with EOGBS sepsis. Blood culture verified 174 cases. There were 145 with clinical sepsis and 180 with pneumonia only. The incidences were 0.40, 0.33, and 0.41 per 1000 live births, respectively. The mortality was 7.5, 0.7, and 2.2% in respective groups. The frequencies of established maternal risk factors were: membrane rupture > or =18 hours, 44%; prematurity, 26%; temperature during labour > or =38 degrees C, 22%. Novel maternal risk factors identified in verified cases were gestational age (GA) of 37 completed weeks (OR 3.5, 1.8-6.5) and gestational diabetes (OR 3.7, 1.8-8.5). When including clinical sepsis, also epidural anaesthesia, infant large for GA, postmaturity, and high maternal age were significant risk factors.

CONCLUSION

The incidence of verified EOGBS disease was 0.4 per 1000 live births with a total burden of EOGBS morbidity approximately three times higher. GA of 37 completed weeks and gestational diabetes were identified as additional significant risk factors.

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.

Is it exposure to cigarette smoke or to smokers which increases the risk of meningococcal disease in teenagers?

BACKGROUND

Passive smoking appears to increase the risk of meningococcal disease (MD) in adolescents. Whether this effect is attributable to exposure to cigarette smoke or contact with smokers is unknown.

METHODS

We conducted a prospective population-based case-control study with age, sex matched-controls in 1:1 matching. Participants were 15-19 year old with MD recruited at hospital admission in six regions (65% of the population of England) from January 1999 through June 2000, and their matched controls. Data on potential risk factors were gathered by confidential interview, including seven passive smoking variables. Factor analysis was performed to assess the dimensionality of the passive smoking exposure variables. The data were analysed with univariate and multivariate conditional logistic regression.

RESULTS

144 case-control pairs were recruited (51% male; median age 17.6). Factor analysis identified two independent factors representing passive smoking (P < 0.01), one associated with 'exposure to smoke', the other with 'smoker contact'. Only smoker contact was a significant risk factor for MD (OR = 1.8; 95% CI 1.0-3.3; P = 0.05). In multivariate analysis this factor was still associated with MD independently of potential confounders such as active smoker status and household crowding.

CONCLUSION

Contact with smokers is associated with increased risk of MD in adolescents. This is more likely to be due to higher carriage rates in smokers than to exposure to smoke and emphasizes the importance of public health measures to stop smoking. In epidemiological studies that assess risk from passive smoking, exposure to smoke should be differentiated where possible from contact with smokers.

Maternal Alcohol Abuse and Neonatal Infection

BACKGROUND

Since chronic alcohol use suppresses the adult immune system, we tested the hypothesis that maternal alcohol ingestion increases the risk of infection in term newborns.

METHODS

Analysis of a large case-control study of birth weight for gestational age was performed focusing on maternal alcohol ingestion and the development of infection in term newborns > or =36 weeks gestation. After delivery, mothers were asked about alcohol and tobacco use in the 3 months prior to conception, the 1st, 2nd, and 3rd trimester of pregnancy.

RESULTS

Eight hundred and seventy-two singleton newborns (872) > or = 36 weeks gestation were identified for analysis. A total of 51 (5.8%) had newborn infections. Gestational age, sex, and small for gestational age (SGA) were similar in the newborns with and without infection (p = NS). Infants whose mothers reported alcohol use, excessive drinking or smoking in pregnancy were more likely to have a newborn diagnosed with an infection than were mothers who reported abstaining from alcohol or cigarettes (p < 0.05). When controlling for race and smoking, SGA infants whose mothers used any alcohol had a 2.5-fold increase risk of infection, while excessive alcohol use increased the risk 3-4-fold. In a multivariable logistic regression analysis controlling for low maternal income, smoking, and SGA, excessive alcohol use during the 2 trimester increased the risk of newborn infection (OR 3.7 [1.1,12.8], p < 0.05).

CONCLUSIONS

Excessive maternal alcohol use is associated with an increased risk of newborn infection in this patient sample. Increased awareness and further clinical investigations are warranted to address the detrimental effects of fetal alcohol exposure on the developing immune system.

Adverse health effects of prenatal and postnatal tobacco smoke exposure on children

Parents who choose to smoke are possibly not aware of, or deny, the negative effects of passive smoking on their offspring. This review summarises a wide range of effects of passive smoking on mortality and morbidity in children. It offers paediatricians, obstetricians, specialists in preventive child health care, general practitioners, and midwives an approach to promote smoking cessation in smoking parents before, during, and after pregnancy.