Intrapartum Prophylaxis Research Articles

Evaluation of Cefotaxime and Desacetylcefotaxime Concentrations in Cord Blood after Intrapartum Prophylaxis with Cefotaxime

Preterm premature rupture of the membranes is associated with a high risk of neonatal sepsis. An increase in the incidence of early-onset neonatal sepsis due to ampicillin-resistant Escherichia coli in premature infants has been observed in the past few years. Intrapartum prophylaxis with ampicillin has proven to be efficient for the prevention of early neonatal sepsis due to group B streptococci. To date, there is no strategy for the prevention of early neonatal sepsis due to ampicillin-resistant E. coli. Our aim was to investigate whether a standardized dosage regimen of intrapartum cefotaxime could provide concentrations in the cord blood greater than the cefotaxime MIC(90) for E. coli. Seven pregnant women hospitalized with preterm premature rupture of the membranes and colonized with ampicillin-resistant isolates of the family Enterobacteriaceae were included. Cefotaxime was given intravenously during delivery, as follows: 2 g at the onset of labor and then 1 g every 4 h until delivery. Blood specimens were collected from the mother 30 min after the first injection and just before the second injection, and at birth, blood specimens were simultaneously collected from the mother and the umbilical cord. The concentrations of cefotaxime in the cord blood ranged from 0.5 to 8.5 mg/liter. The MIC(90) of cefotaxime for E. coli strains (0.125 mg/liter) was achieved in all cases. This preliminary study supports the use of cefotaxime for intrapartum prophylaxis in women colonized with ampicillin-resistant isolates of Enterobacteriaceae. The effectiveness of this regimen for the prevention of neonatal sepsis needs to be evaluated with a larger population.

Duration of Intrapartum Prophylaxis and Concentration of Penicillin G in Fetal Serum at Delivery

A minimum of 4 hours of intrapartum antibiotic prophylaxis before delivery is generally recommended to prevent early-onset group B Streptoccocus (GBS) because less than 4 hours may not achieve adequate levels of drug. The aim of this prospective cohort study was to compare fetal penicillin levels among fetuses exposed to less than 4 hours and those exposed for longer durations. Ninety-eight laboring GBS-positive women carrying singleton gestations 37 weeks’ or greater received 5 million units of intravenous penicillin G followed by a maintenance dose of 2.5 million units every 4 hours until delivery. Penicillin G levels in umbilical cord blood samples collected at delivery were measured by high-performance liquid chromatography. The investigators found that fetuses exposed to fewer than 4 hours of prophylaxis had significantly higher penicillin G levels than those exposed to greater than 4 hours (P = .003). Multivariable linear regression analysis showed that fetal penicillin G levels were associated with duration of exposure, time since last dose, dosage, and number of doses, but not maternal body mass index. Penicillin G levels increased linearly and peaked at approximately 1 hour (R2 = .40) and then decreased rapidly according to a power-decay model (R2 = .67). Cord blood levels did not accumulate after repeated maintenance dosing, and returned to baseline after each 4-hour interval. Fetal serum penicillin levels far exceeded the minimal inhibitory concentration less than 1 hour after the initial dose. Unlike previous findings, these data demonstrate that infants exposed to fewer than 4 hours of prophylaxis are not necessarily at increased risk for GBS sepsis. Given the rapid transfer of penicillin from mother to fetus, the authors suggest that antibiotic prophylaxis should be pursued even in the most precipitous of deliveries.

Continued early onset group B streptococcal infections in the era of intrapartum prophylaxis

The objective of the study was to determine the rate of early onset group B streptococcus (EOGBS) infection in Utah and identify potential areas of failure in EOGBS prevention. We queried the microbiology records of Intermountain Healthcare for infants with culture-confirmed EOGBS between 1 January 2002 and 31 May 2006 and calculated rates of EOGBS per 1000 deliveries. We reviewed the infant and maternal records of each EOGBS case to identify possible failures in EOGBS prevention. There were 54 cases of EOGBS among the 127 205 births (0.42/1000 births). Of all, 12 were preterm. Of the 39 (93%) women prenatally screened for GBS, 31 (79%) had negative results and 7/8 (88%) women with positive prenatal GBS screens either did not receive intrapartum antibiotic prophylaxis (IAP) or received inadequate IAP. Of the 54 infants with EOGBS, 3 (6%) died. Utah's rates of EOGBS were higher than the national average. Factors associated with EOGBS include missed screening opportunities, inadequate IAP, and false-negative maternal GBS culture.

Duration of Intrapartum Prophylaxis and Concentration of Penicillin G in Fetal Serum at Delivery

Intrapartum penicillin G prophylaxis aims to prevent early-onset group B streptococci (GBS) sepsis by interrupting vertical transmission. We examined the relationship between duration of prophylaxis and fetal serum penicillin G levels among fetuses exposed to fewer than 4 hours of prophylaxis compared with longer durations. In this prospective cohort study, 98 laboring GBS-positive women carrying singleton gestations at 37 weeks or greater were administered 5 million units of intravenous penicillin G followed by 2.5 million units every 4 hours until delivery. Umbilical cord blood samples were collected at delivery, and penicillin G levels were measured by high-performance liquid chromatography. Intraassay and interassay coefficients of variation were less than 3%. Fetuses exposed to fewer than 4 hours of prophylaxis had higher penicillin G levels than those exposed to greater than 4 hours (P=.003). In multivariable linear regression analysis, fetal penicillin G levels were determined by duration of exposure, time since last dose, dosage, and number of doses, but not maternal body mass index. Penicillin G levels increased linearly until 1 hour (R(2)=.40) and then decreased rapidly according to a power-decay model (R(2)=.67). All subgroups analyzed were above the minimal inhibitory concentration (MIC) for GBS (0.1 micrograms/mL)(P<.002). Individual samples were 10-179-fold above the MIC. In patients receiving maintenance dosing, penicillin G did not accumulate in the cord blood and returned to baseline after each 4-hour interval. Short durations of prophylaxis achieved levels significantly above the MIC, suggesting a benefit even in precipitous labors. The designation of infants exposed to fewer than 4 hours of prophylaxis as particularly at risk for GBS sepsis may be pharmacokinetically inaccurate.

Evaluation of liquid biphasic Granada medium and instant liquid biphasic Granada medium for group B streptococcus detection

Group B streptococci (GBS) are transmitted from the mother to the newborn. Prevention of neonatal infection is achieved by intrapartum prophylaxis given to mothers colonized with GBS at 35 to 37 weeks of pregnancy. Liquid biphasic Granada medium (LB) and instant liquid biphasic Granada medium (ILB) were evaluated for GBS detection. Vaginal swabs obtained from 300 women were inoculated onto LB or ILB, or onto Todd-Hewitt broth and analyzed with the ATB system (comparison method). Prevalence of GBS was 20% (61/300). LB and Todd-Hewitt with ATB detected GBS in 20% of women, and ILB in 19% of women. No growth was observed at four hours in any of the media studied. At 10 h and 14 h, identification of GBS was possible in 43/300 (14%) and 53/300 (18%) of ILB cultures, respectively, and in 32/300 (11%) and 46/300 (15%) of LB cultures. All the media used are suitable for GBS detection. The majority of GBS were identified in ILB and LB cultures at 10 h and 14 h.

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To assess the benefits of a chemoprophylaxis program based on screening women for group B streptococcus (GBS) infection between 30 and 32 weeks of pregnancy in a population with a high rate of premature births.From 1995 to 2011, 24 950 women were screened for GBS infection between 30 and 32 weeks of pregnancy at Markusovszky Teaching Hospital, Szombathely, Hungary. Those who tested positive, and those who tested negative but were at risk of infecting their newborns, underwent intrapartum prophylaxis. Neonatal outcomes were compared with those of a historical cohort that underwent no screening or treatment, and with those published in CDC/ACOG guidelines recommending screening closer to term.There were 63 infected newborns (0.2%) in the study cohort, and 1 of 8 with sepsis died. There were 149 infected newborns (0.7%) in the historical cohort, and 29 of 31 with sepsis died.Screening women early in a population with a high rate of premature births may simplify preterm labor management. It results, however, in a higher incidence of early onset neonatal GBS disease than when screening is done closer to term.

Three New Macrolide Efflux ( mef ) Gene Variants in Streptococcus agalactiae

Streptococcus agalactiae (group B streptococcus [GBS]) is the most common cause of neonatal sepsis (9). Penicillin is used for intrapartum prophylaxis, but erythromycin or clindamycin is recommended for patients allergic to penicillin (3). There are two major mechanisms of erythromycin resistance in S. agalactiae, (i) erythromycin ribosomal methylase, mediated by ermB, ermA, ermTR, or ermC, which confers cross-resistance to macrolides, lincosamides, and streptogramin B (MLSB phenotype), and (ii) a less common macrolide efflux pump, mediated by mef (7), which confers resistance to 14- and 15-membered macrolides only (M phenotype). The major mef variants, mefE and mefA, were originally identified in S. pneumoniae and S. pyogenes, respectively (5, 11); both are found in S. agalactiae (2), although mefE is much more common (4, 12). Recently, we tested 512 GBS isolates from Australia, Hong Kong, and South Korea by using a multiplex PCR-based reverse line blot (mPCR/RLB) assay to identify nine resistance markers and identified mef in 22 (12). However, we did not distinguish mef variants. Subsequently, we tested a total of 1,629 GBS clinical isolates (including the original 512) from nine countries by using the same mPCR/RLB, except that two new probe pairs, specific for mefA and mefE, were added (Table ​(Table1).1). Isolates were typed by using a three-set genotyping system which identifies the molecular serotype (MS), surface protein genes, and mobile genetic elements, as described previously (8). Antibiotic susceptibilities to erythromycin, clindamycin, and tetracycline were measured by E-test (AB Biodisk; Australia Laboratory Services Pty. Ltd.) and interpreted as recommended by the Clinical and Laboratory Standards Institute (12). TABLE 1. Oligonucleotide primers and probes used in this study Forty five (2.7%) of 1,629 isolates were positive for mef, and of these, 35 contained mefE, 7 contained mefA, and 3 gave weak or variable signals with mefE- and mefA-specific probes. These three isolates were among 16 mef-positive isolates from Hong Kong. Their genotypes and phenotypic susceptibilities to erythromycin, clindamycin, and tetracycline are shown in Table ​Table2.2. All three had the M phenotype and MS Ia but atypical genotypes. MS Ia usually has the surface protein gene alp1 and insertion sequence IS1381 (8, 10). Two of these isolates had alp1 but, instead of IS1381, carried the type II intron GBSi1, usually found in MS III but rarely in other serotypes (10). The other isolate had neither the surface protein gene nor the insertion sequence. TABLE 2. Characteristics and comprehensive genotyping results of three mef variants From each of these three isolates, mef was amplified and sequenced with the primers shown in Table ​Table1.1. The full sequences indicated that all were novel mef variants not previously described in a GBS. They were deposited in GenBank with accession numbers {type:entrez-nucleotide-range,attrs:{text:DQ445269 to DQ445271,start_term:DQ445269,end_term:DQ445271,start_term_id:90902659,end_term_id:90902663}}DQ445269 to DQ445271. {type:entrez-nucleotide,attrs:{text:DQ445271,term_id:90902663,term_text:DQ445271}}DQ445271 and {type:entrez-nucleotide,attrs:{text:DQ445270,term_id:90902661,term_text:DQ445270}}DQ445270 were 99% similar to each other but only 88% and 89% homologous with mefE (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AF227521,term_id:18478326,term_text:AF227521}}AF227521) and mefA (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AY064721,term_id:22121176,term_text:AY064721}}AY064721), respectively. They shared 99 to 100% homology with a mef variant recently identified in Streptococcus dysgalactiae (a group G streptococcus) (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AM168138,term_id:83582439,term_text:AM168138}}AM168138 and {type:entrez-nucleotide,attrs:{text:AY355405,term_id:34147931,term_text:AY355405}}AY355405) (1). {type:entrez-nucleotide,attrs:{text:DQ445269,term_id:90902659,term_text:DQ445269}}DQ445269 has not been described before; it had 89% homology with mefA (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AY064721,term_id:22121176,term_text:AY064721}}AY064721) and the novel group G streptococcus mef gene (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AY355405,term_id:34147931,term_text:AY355405}}AY355405), 91% homology with mefE (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AY227521,term_id:29653143,term_text:AY227521}}AY227521), and 92% homology with another mef variant, mefI, described in Streptococcus pneumoniae (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AJ971089,term_id:194032949,term_text:AJ971089}}AJ971089) (6). The inconsistent mPCR/RLB results for these isolates can be explained by mutations in the mefAESb and mefAEAb regions. New primers and probes will be required to detect them reliably by mPCR/RLB. For these novel mef variants, we propose the names mefG (for {type:entrez-nucleotide,attrs:{text:DQ445270,term_id:90902661,term_text:DQ445270}}DQ445270 and {type:entrez-nucleotide,attrs:{text:DQ445271,term_id:90902663,term_text:DQ445271}}DQ445271) and mefB (for {type:entrez-nucleotide,attrs:{text:DQ445269,term_id:90902659,term_text:DQ445269}}DQ445269) to reflect the beta-hemolytic streptococcus groups in which they were first identified. These findings and the atypical genotype patterns suggest that these strains have arisen by recombination. Further investigation will be required to determine their clinical significance.

Phenotypical characteristics of group B streptococcus in parturients

Colonization by Group B Streptococcus (GBS) is highly prevalent among pregnant women, with prevalence rates ranging between 4% and 30%. The infection may be transmitted vertically and may result in serious neonatal consequences. In the period from November 2003 to May 2004, a cross-sectional study was carried out among 316 parturients at the Jundiaí Teaching Hospital to establish the prevalence of genital GBS colonization, to identify the factors associated with colonization and the characteristic phenotypes of these streptococci. Samples from rectal and vaginal areas were collected for selective culture in Todd-Hewitt broth. Susceptibility to 7 antimicrobial agents was tested using the antibiotic diffusion disk technique, and the isolated strains were classified using specific antisera. The prevalence of GBS colonization was 14.6%. No strain was resistant to penicillin, ampicillin, erythromycin or nitrofurantoin. The majority of strains were sensitive to cephalothin. Greatest resistance was to gentamicin (76.1%), followed by clindamycin (17.4%). The most frequent serotype was Ib (23.9%), followed by serotypes II and Ia (19.6% and 17.4%, respectively). There was no correlation between serotype and greater antimicrobial resistance. In conclusion, the prevalence of GBS in parturients was high and penicillin continues to be the drug of choice for intrapartum prophylaxis. The most frequent serotype (Ib) found in this study differs from those found in the majority of studies carried out in other countries, revealing the need to identify prevalent serotypes in each region so that specific vaccines can be designed.

Rapid HIV testing, pregnancy, antiretroviral prophylaxis and infant abandonment in St Petersburg

In St Petersburg, Russia, a rapid HIV-testing programme was implemented in April 2004 for high-risk women giving birth. Among 670 women without prenatal care who received rapid HIV testing, 6.4% (43) had positive results. Among HIV-positive mothers, receipt of intrapartum antiretroviral prophylaxis increased significantly compared to pre-programme levels (76 versus 41%). Additionally, infant abandonment increased significantly (50% versus 26%), and was 10 times greater in women with unintended versus intended pregnancies (73% versus 7%).

Procedures for prevention of perinatal group B streptococcal diseases: a multicenter questionnaire survey of hospitals in the Kyoto Neonatal Disease Study Group, Japan

To explore clinical protocols for the prevention of early-onset group B Streptococcus (EOGBS) disease of the newborn in Japan, we conducted a multicenter questionnaire survey. Of 32 regional centers participating in the Kyoto Neonatal Study Group, 28 provided usable data concerning prevention practices undertaken between 2000 and 2004. Twenty-three (82%) of the 28 hospitals implemented bacteriological screening to identify maternal GBS carriage, and all 23 hospitals administered intrapartum antibiotics to all screening-positive pregnant women. There were no institutes that used risk-based strategies. In the 23 hospitals, bacteriological screening was conducted mostly by lower vaginal swab alone (n = 18). Eighteen hospitals performed screening once during pregnancy, either before 34 weeks' gestation (n = 6) or between 35 and 37 weeks' gestation (n = 12). Oral antepartum antibiotics, when carriage was identified, were administered at 12 (52%) hospitals. Twenty institutes used penicillins for intrapartum prophylaxis. However, the loading dose for chemoprophylaxis ranged from 0.5 to 2 g, and the interval between repeat administrations ranged from 4 to 12 h. Although the results indicated that more than 80% of the hospitals surveyed had introduced some screening-based prevention practices, the timing of the bacteriological screening during the pregnancy, the number of screenings, and the screening sites, as well as the antibiotics used, and their dosage, varied widely. Because of these highly variable methods, the efficacy of the implementation of preventive practices could not be determined. This study is the first to have described preventive practices for EOGBS disease in Japan in the era of Centers for Disease Control and Prevention guidelines. In light of the above results, a larger study under a unifying protocol would be warranted.

Duration of Intrapartum Prophylaxis for Neonatal Group B Streptococcal Disease

To examine published evidence regarding duration of intrapartum antibiotic prophylaxis administered to pregnant women colonized with group B Streptococcus (GBS) to reduce infant colonization with GBS and to prevent early-onset GBS sepsis. A search was conducted in The Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2006), MEDLINE (1966 to January 2006), EMBASE (1980 to January 2006), CINAHL (1982 to January 2006), and in protocols and guidelines of the Centers for Disease Control and Prevention, American Academy of Pediatrics, and American College of Obstetrics and Gynecology. All randomized controlled trials and observational studies in which duration of intrapartum antibiotic prophylaxis is reported relative to subsequent neonatal GBS colonization or sepsis were considered. Case series and study designs using historical cohorts or controls for comparison were excluded. Three prospective cohort studies and one case-control study met inclusion criteria. Heterogeneity of study design and assembly of cohorts precluded meta-analysis. A systematic review of the individual studies was performed. All studies were rated as fair or poor validity with regard to their ability to evaluate duration of intrapartum prophylaxis and transmission of GBS to the newborn. All 4 studies were largely composed of women with existing risk factors for GBS disease of the newborn. One study supported more than 1 hour of prophylaxis, two studies supported more than 2 hours of prophylaxis, and one was inconclusive. Despite unequivocal clinical guidelines recommending at least 4 hours of intrapartum antibiotic prophylaxis, there are no well-designed studies examining duration of intrapartum antibiotic prophylaxis for prevention of early-onset GBS disease of the newborn. We recommend continuing to initiate intrapartum prophylaxis according to the American College of Obstetricians and Gynecologists guidelines; however, the transmission of GBS to neonates exposed to less than 4 hours of intrapartum prophylaxis and their subsequent management require further study.

Perinatal Group B Streptococcal Infections and the New Guidelines

After completing this article, readers should be able to: 1. Describe the current literature on surveillance studies and patient outcomes regarding group B Streptococcus (GBS) disease. 2. Discuss the current perinatal GBS prevention guidelines. 3. Describe the limitations of the “limited evaluation” in assessing newborns at risk for GBS disease. 4. Delineate the proposed management of asymptomatic infants at risk for GBS disease, with the goal of decreasing unnecessary testing and avoiding prolonged hospitalization. Group B Streptococcus (GBS), also known as S agalactiae , is an encapsulated gram-positive bacterium that is a common inhabitant of the human gastrointestinal and genitourinary tracts. Despite recent reductions in incidence, it remains the most common cause of neonatal bacterial infections in most developed countries. The most desirable approach suggested to eliminate neonatal GBS infection is the use of GBS vaccines prior to or early in pregnancy. However, until effective GBS vaccines become available, screening pregnant women for GBS colonization and providing intrapartum antibiotic prophylaxis (IAP) will continue to be the mainstay for prevention of GBS infection in neonates, as suggested by the Centers for Disease Control and Prevention (CDC). A 70% decline in the rate of early-onset GBS disease followed the introduction of the first national consensus guidelines in 1996. In 2002, new national guidelines were released based on evidence that the screening-based strategy was superior to a risk factor-based strategy for preventing GBS infections in the neonate. As a result of many obstetricians adopting the screening-based strategy, CDC data from 2004 showed a further decline in the incidence of early-onset GBS infection to 0.34 cases per 1,000 live births. This surpasses the Healthy People 2010 objective of a reduction in the incidence of early-onset disease to 0.5 cases per 1,000 live births for all races. It should be mentioned that different countries may demonstrate different results, but …

Compliance with a risk factor‐based intrapartum prophylaxis program for neonatal group B streptococcal disease

The US Centre for Disease Control (CDC) recently amended their guidelines for the prevention of early-onset group B streptococcal disease (EOGBSD) of the newborn to recommend bacteriological screening, rather than risk factor-based screening, as the preferred method of identifying 'at risk' mother-infant pairs. This recommendation was derived from population data suggesting that the effectiveness of bacteriological screening was superior to a risk-factor approach because antibiotic compliance was better with the former. Whether poor compliance and therefore impaired prevention is inherent in risk-factor screening has not been widely tested. For a 6-month period we audited compliance with an established risk-factor EOGBSD prophylaxis program. During the audit period, 1243 women delivered, of whom 287 (23%) had at least one risk factor. Of these women, 193 (67%), representing 15% of all women giving birth, received antibiotics. Thus, there were 94 women who were eligible for antibiotics but did not receive prophylaxis. There were sound clinical reasons for withholding antibiotics in 68 of these. Therefore, the corrected compliance rate within our program was 73%. This compares favourably with published compliance rates with bacteriological-based programs, but we have suggested mechanisms to improve compliance further.

Early-Onset and Late-Onset Neonatal Group B Streptococcal Disease—United States, 1996-2004

In 2002, CDC, the American College of Obstetricians and Gynecologists (ACOG), and the American Academy of Pediatrics (AAP) issued revised guidelines for prevention of perinatal invasive group B streptococcal (GBS) disease. These guidelines recommend universal screening of pregnant women for rectovaginal GBS colonization at 35-37 weeks' gestation and administering intrapartum antimicrobial prophylaxis to carriers. To assess the impact of the guidelines on multistate trends in neonatal GBS disease incidence, CDC analyzed data from the Active Bacterial Core surveillance (ABCs) system from 1996-2004. This report summarizes the results of that analysis, which determined that incidence of GBS disease in infants aged 0-6 days (i.e., early-onset disease) in 2004 had decreased by 31% from 2000-2001, the period immediately before universal screening was implemented. Incidence of GBS disease in infants aged 7-89 days (i.e., late-onset disease) remained unchanged during the 9-year period reviewed. Continued monitoring is needed to assess the impact of the 2002 guidelines on early-onset disease and the long-term effect of widespread intrapartum use of antimicrobial agents on neonatal GBS disease.

Frequency of antimicrobial resistance among invasive and colonizing Group B streptococcal isolates.

BackgroundGroup B Streptococcus (GBS) remains susceptible to penicillin, however, resistance to second-line antimicrobials, clindamycin and erythromycin, has increased since 1996. We describe the age-specific antibiotic susceptibility profile and capsular type distribution among invasive and colonizing GBS strains.MethodsWe tested 486 invasive GBS isolates from individuals of all ages collected by a Wisconsin surveillance system between 1998 and 2002 and 167 colonizing strains collected from nonpregnant college students during 2001 in Michigan. Antimicrobial susceptibility testing was performed by disk diffusion or Etest and capsular typing was performed using DNA dot blot hybridizationResults20.0% (97/486) of invasive and 40.7% (68/167) of colonizing isolates were resistant to clindamycin (P < .001) and 24.5% (119/486) of invasive and 41.9% (70/167) of colonizing isolates were resistant to erythromycin (P < .001). Similarly, 19.8% (96/486) of invasive and 38.3% (64/167) of colonizing isolates were resistant to both antimicrobial agents (P < .001). 29.4% (5/17) of invasive isolates from persons 18–29 years of age and 24.3% (17/70) of invasive isolates from persons 30–49 years of age were resistant to clindamycin. Similarly, 35.3% (6/17) of invasive isolates from persons 18–29 years of age and 31.4% (22/70) of invasive isolates from persons 30–49 years of age were resistant to erythromycin. 34.7% (26/75) of invasive isolates from persons < 1 year of age were capsular type Ia, whereas capsular type V predominated among isolates from adults.ConclusionClindamycin and erythromycin resistance rates were high among isolates colonizing nonpregnant college students and invasive GBS isolates, particularly among the colonizing isolates. Susceptibility profiles were similar by age although the proportion of clindamycin and erythromycin resistance among invasive isolates was highest among persons 18–49 years of age. Increasing antimicrobial resistance has implications for GBS disease treatment and intrapartum prophylaxis among penicillin intolerant patients.

A trial of preventing early- and late-onset Group B streptococcal sepsis with combined intrapartum chemoprophylaxis and universal neonatal screening

Prevention of early-onset Group B Streptococcal (GBS) infection has been attempted by employing universal maternal screening for GBS, intrapartum chemoprophylaxis, and a single dose of penicillin given to neonates in the first hour of life. This strategy, however, does not seem to prevent the occurrence of late-onset neonatal group B streptococcal disease. We assessed early and late-onset GBS disease with the use of a before-after study designed to evaluate the implementation of intrapartum antimicrobial prophylaxis. Moreover, universal neonatal screening for colonization of GBS was carried out with swabs of the external ear canal. Newborns with GBS colonization received a preventive treatment with oral amoxicillin for 10 days. Early-onset GBS infection decreased from 0.5 per thousand at baseline period to 0.19 per thousand at the study period. The incidence of late-onset GBS disease decreased from 1:1348 (0.74 per thousand) to 1:20,710 (0.048 per thousand). The overall cost for universal neonatal screening paid for by the Italian Health System in the study period was 31,065 US dollars with an antibiotic prophylaxis cost of 2,399 US dollars. A combined strategy based on GBS culture screening and assessment of risk factors for perinatal GBS disease can significantly reduce the rate of both early and late-onset GBS infections.

Neonatal E. coli Infections — and Intrapartum GBS Prophylaxis?

Since the 1970s, group B Streptococcus (GBS) has been a major cause of invasive neonatal infections. Efforts to prevent mother-to-infant transmission of GBS have evolved over the years but have focused on intrapartum prophylaxis for women whose infants are at risk. In 1996, guidelines recommending penicillin or ampicillin prophylaxis for women with late antenatal GBS …

Simultaneous Detection of Nine Antibiotic Resistance-Related Genes in Streptococcus agalactiae Using Multiplex PCR and Reverse Line Blot Hybridization Assay

Streptococcus agalactiae (group B streptococcus [GBS]) is the leading cause of neonatal and maternal sepsis. Penicillin is recommended for intrapartum prophylaxis, but erythromycin or clindamycin is used for penicillin-allergic carriers. Antibiotic resistance (AR) has increased recently and needs to be monitored. We have developed a multiplex PCR-based reverse line blot (mPCR/RLB) hybridization assay to detect, simultaneously, seven genes encoding AR--erm(A/TR), erm(B), mef(A/E), tet(M), tet(O), aphA-3, and aad-6--and two AR-related genes, int-Tn and mreA. We tested 512 GBS isolates from Asia and Australasia and compared mPCR/RLB with antibiotic susceptibility phenotype or single-gene PCR. Phenotypic resistance to tetracycline was identified in 450 (88%) isolates, of which 442 had tet(M) (93%) and/or tet(O) (6%). Of 67 (13%) erythromycin-resistant isolates, 18 were susceptible to clindamycin, i.e., had the M phenotype, encoded by mef(A/E); 39 had constitutive (cMLS(B)) and 10 inducible clindamycin resistance, and of these, 34 contained erm(B) and 12 erm(A/TR). Of four additional isolates with mef(A/E), three contained erm(B) with cMLS(B) and one was erythromycin susceptible. Of 61 (12%) clindamycin-resistant isolates, 20 were susceptible to erythromycin and two had intermediate resistance. Based on sequencing, 21 of 22 isolates with mef had mef(E), and 8 of 353 with int-Tn had an atypical sequence. Several AR genes, erm(B), tet(O), aphA-3, aad-6, and mef(A/E), were significantly more common among Asian than Australasian isolates, and there were significant differences in distribution of AR genes between GBS serotypes. Our mPCR/RLB assay is simple, rapid, and suitable for surveillance of antibiotic resistance in GBS.

Efficacy of intramuscular penicillin in the eradication of group B streptococcal colonization at delivery

Objective. Due to rapid deliveries and human error, not all group B streptococcal positive mothers will receive adequate prophylactic antibiotic treatment in labor. We sought to determine if long acting intramuscular penicillin given after a positive culture result would be efficacious in eradicating group B streptococcal colonization at the time of delivery.Methods. Patients positive for group B streptococci at 35–37 weeks were randomized to receive 2.4 million units of intramuscular benzathine penicillin G suspension (Bicillin® L-A) versus no treatment. Study patients were recultured at the time of admission to labor and delivery prior to receiving prophylactic antibiotics according to CDC guidelines.Results. A total of 53 patients were enrolled. A small but significant decrease in the rate of group B streptococcal colonization was observed in the treatment group (14/27, 52%) versus the control group (20/23, 87%), p = 0.03.Conclusion. The large number of persistent carriers suggests that 2.4 million units of intramuscular benzathine penicillin G suspension (Bicillin® L-A) is insufficient as sole therapy. However, the decline in group B streptococcal carriers might lessen the risk of failed or insufficient intrapartum treatment. Intramuscular benzathine penicillin G suspension (Bicillin® L-A) may be useful as an adjunctive treatment for patients at risk for rapid delivery, before adequate intrapartum prophylaxis can be given.

Audit of intrapartum group B streptococcus prophylaxis

SummaryGroup B streptococcus is the most frequent cause of severe early onset neonatal infection. For over 3 years our department has employed a risk-factor-based protocol of intra-partum antibiotic prophylaxis. Prophylaxis has been considered adequate if women receive antibiotics more than 4 hours before delivery. This study aims (1) to establish the adequacy of intrapartum prophylaxis in routine clinical practice and (2) to determine whether changing the time interval (from commencement of prophylaxis to delivery) for adequacy from 4 to 2 hours (based on RCOG guidelines) improves the percentage of women receiving adequate prophylaxis. This was an audit against established protocol. Case notes of consecutive deliveries over a 4-week period were reviewed retrospectively. A total of 396 deliveries occurred during the study period. Some 44 women (11%) were eligible for antibiotic prophylaxis. Adequate prophylaxis was achieved in 21 cases (49%). If the time for prophylaxis to be considered adequate was reduced from 4 to 2 h, the number of women receiving adequate prophylaxis increased to 33 (76%). In conclusion, despite the protocol being well established, only half of the eligible women receive adequate intra-partum prophylaxis. Reducing the time interval from 4 to 2 h appreciably increases the number of women receiving adequate prophylaxis, which reduces the necessity of providing neonatal prophylaxis.