Late-onset Group B Streptococcus Disease Research Articles

Horizontal transmission of group B streptococcus in a neonatal intensive care unit

The incidence of early-onset group B streptococcal (GBS) sepsis in the neonatal population has decreased substantially since the introduction of maternal intrapartum antibiotic prophylaxis and routine prenatal screening. However, these strategies have not reduced the incidence of late-onset GBS infections. Additional research pertaining to the transmission of late-onset GBS infections is required to develop effective preventive methods. The present report describes probable horizontal transmission of late-onset GBS infection among three infants in a neonatal intensive care unit. GBS strain confirmation was based on the microbiological picture, antibiogram and pulsed-field gel electrophoresis. These cases highlight the morbidity associated with late-onset GBS disease and the importance of considering horizontal transmission as an etiological factor in GBS infection in the newborn period. Further studies assessing horizontal transmission in late-onset GBS disease may improve prevention and early intervention.

A Four-week-old Infant With an Intracardiac Mass

A Four-week-old Infant With an Intracardiac Mass

Outbreak of late-onset group B Streptococcus in a neonatal intensive care unit

In September 2007, the Tennessee Department of Health was notified of a cluster of late-onset group B streptococcal (GBS) infections in a neonatal intensive care unit (NICU). Outbreaks of late-onset GBS are rare. A case was defined as culture-confirmed invasive GBS infection in a neonate aged > or =7 days, identified in hospital A during August 23 to September 6, 2007. We reviewed medical records; examined NICU microbiology reports; and performed serotyping, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) on invasive isolates. Maternal GBS screening, prophylaxis, and infection control policies were reviewed and staff practices observed. Five cases of late-onset GBS were identified. None of the mothers of the infants received optimal GBS prophylaxis. Patient isolates were of 2 serotypes, 3 PFGE patterns, and 2 MLST patterns. Three isolates were indistinguishable on subtyping. These 3 cases were clustered in time. No common health care providers were identified. Infection control deviations in the NICU were observed. We identified a multiclonal cluster of 5 late-onset GBS cases. Multiple factors likely contributed to the outbreak, including nosocomial transmission of GBS. Further efforts to prevent late-onset GBS disease are necessary.

Revisiting the Need for Vaccine Prevention of Late-Onset Neonatal Group B Streptococcal Disease

Intrapartum antibiotic prophylaxis for neonatal group B streptococcal disease (GBS) effectively prevents disease among infants <7 days old, but there are no prevention strategies for late-onset GBS disease (onset on days 7-89 of life). We describe trends in late-onset GBS over a 16-year period to characterize disease burden and estimate vaccine preventability. We conducted active, population-based surveillance for invasive late-onset GBS disease in 10 states from 1990 to 2005. A case was defined by GBS isolation from a normally sterile site on day 7-89 of life in a surveillance area resident. Incidence rates were calculated per 1000 resident live births. We identified 1726 cases; 26% presented with meningitis, and the case fatality ratio was 4.3%. Incidence was similar throughout the study period. Incidence among black infants was approximately 3 times that among non-black infants; the disparity persisted when data were stratified by gestational age. We estimate approximately 1300 cases of late-onset GBS occur annually in the United States. Birth at <37 weeks gestation was common among case-infants (49%) and was associated with elevated case fatality (relative risk: 3.8; 95% confidence interval: 1.1-13.2). Of 653 serotyped isolates, serotypes III (53%), IA (24%), and V (13%) predominated. During 2003-2005, 81 (36%) of the 227 cases caused by serotypes III, IA, and V were born before 34 weeks gestation. The late-onset GBS disease burden remains substantial. A trivalent vaccine could be an effective prevention strategy. Because many cases were born preterm, reducing the opportunity for transplacental antibody transfer, adolescent immunization should be considered.

Neonatal group B streptococcal disease: Incidence, presentation, and mortality

Objectives. To ascertain the incidence, and compare the clinical characteristics, laboratory parameters, and immediate mortality of neonates with early-onset (symptomatic and asymptomatic) and late-onset group B streptococcal (GBS) disease.Methods. A chart review of 81 neonates with GBS disease (either blood and/or cerebrospinal fluid culture-proven) born between 1995 and 2002 admitted to two tertiary care perinatal centers in Toronto was conducted. Clinical characteristics were compared for (1) asymptomatic early-onset, symptomatic early-onset, and late-onset GBS disease and (2) survivors and non-survivors.Results. The incidence of GBS disease was 1.13/1000 live births. One or more antepartum or intrapartum predisposing factors were recognized in 62% of cases. Early-onset was noted in 65 (80%) neonates (23 asymptomatic and 42 symptomatic). All full-term infants survived. The mortality was 6% and was confined to preterm neonates with early symptomatic disease who presented with shock and had thrombocytopenia.Conclusion. Antepartum or intrapartum known predisposing risk factors of GBS disease were lacking in one third of patients. Patients who died were preterm infants in the early symptomatic group.

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 …

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.

Prematurity is the major risk factor for late-onset group B streptococcus disease.

A case-control study was conducted in the greater Houston area to determine risk factors for late-onset group B streptococcus (GBS) disease (onset of disease or first positive culture between 7 and 180 days after birth). Characteristics of 122 case patients diagnosed during 1995-2000 were compared with control subjects matched for birth hospital and date of birth. Half the case patients were preterm infants, 84% of whom were born at <34 weeks of gestation. The risk for late-onset GBS disease increased by a factor of 1.34 (95% confidence interval [CI], 1.15-1.56) for each week of decreasing gestation, by 3.70 (95% CI, 1.35-10.1) for infants of black mothers, and by 4.15 (95% CI, 1.27-13.60) for infants of mothers with a positive GBS screening. These risk factors are similar to that of early-onset GBS disease. However, prematurity is the major risk factor for late-onset GBS disease.

Late-onset and Recurrent Neonatal Group B Streptococcal Disease Associated with Breast-milk Transmission

The purpose of the study was to determine the epidemiological relationships in three unrelated cases of neonatal late-onset Group B streptococcal (GBS) disease and maternal breast-milk infection with GBS. All deliveries were by cesarean section; case 1 was at term, and cases 2 and 3 were at 32- and 33-wk gestation, respectively. Case 1 relates to a mother with clinical mastitis and recurrent GBS infection in a 20-day-old male infant. Following antibiotic therapy and cessation of breast-feeding, the infant recovered without sequelae. Case 2 refers to a mother with clinical mastitis and the occurrence of late-onset GBS disease in 5-wk-old male twins. Despite intervention, one infant died and the second became ill. Following antibiotic therapy and cessation of breast-feeding, the surviving infant recovered without sequelae. Case 3 refers to a mother with sub-clinical mastitis and late-onset GBS infection occurring in a 6-day-old female twin. Following intervention, the infant recovered but suffered a bilateral thalamic infarction resulting in developmental delay and a severe seizure disorder. Following recovery of GBS from an inapparent mastitis and cessation of breast-feeding, the second infant remained well. Blood cultures from all affected infants and maternal breast milk were positive for GBS. Epidemiological relationships between neonatal- and maternal-derived GBS isolates were confirmed by a random amplified polymorphic DNA polymerase chain reaction assay (RAPD-PCR). This study is significant in that it has demonstrated that maternal milk (in cases of either clinical or sub-clinical mastitis) can be a potential source of infection resulting in either late-onset or recurrent neonatal GBS disease.

Group B Streptococcal Infections

1. Samuel P. Gotoff, MD* 1. *Professor and Chairman, Department of Pediatrics, Rush Children’s Hospital, Chicago, IL After completing this article, readers should be able to: 1. Delineate the epidemiologic factors in the transmission of group B Streptococcus (GBS) neonatal infections. 2. List the major factors that increase the risk of neonatal GBS infections. 3. Describe four clinical presentations of neonatal GBS infections. 4. List the laboratory methods for isolating and identifying GBS in mixed flora, normally sterile biologic fluids, and a patient treated with a penicillin. The group B Streptococcus (GBS) initially was isolated by Nocard in 1887 and described as Streptococcus agalactiae , a cause of bovine mastitis. The organism is an encapsulated gram-positive diplococcus that usually produces a narrow zone of beta-hemolysis on blood agar. Most strains are resistant to bacitracin. The streptococci were classified serologically in the 1930s by Lancefield, based on cell wall polysaccharides. The GBS organisms are differentiated further by type-specific capsular polysaccharides and protein antigens. Current serotypes include: Ia, Ib, Ia/c, II, III, IV, V, VI, VII, and VIII. Since the mid-1960s, GBS has become the major cause of bacterial infections in the perinatal period, including bacteremia, amnionitis, endometritis, and urinary tract infection in pregnant women as well as focal and systemic infections in newborns. It is a relatively rare cause of infection in older children and nonpregnant adults. GBS early-onset disease (EOD) occurs within the first week after birth, usually before 72 hours. GBS late-onset disease (LOD) accounts for about 20% of cases, usually occurring between 1 to 4 weeks after birth, but rarely seen up to 6 months of age. Late, late-onset infections, which occur from 1 to 6 months of age, and infections in nonpregnant adults often are associated with immunodeficiency. All of the serotypes have been associated with GBS EOD, with Ia, II, III, and V being most common in the United States. GBS LOD is caused by serotype III …

Prevention of early-onset group b streptococcal disease: Another look at single-dose penicillin at birth

To determine the effect of single-dose penicillin given at birth on the rate of early-onset group B streptococcal (GBS) invasive disease in an inner-city population. Laboratory-based surveillance of GBS disease from 1972-1994 at Parkland Memorial Hospital and Children's Medical Center in Dallas, Texas, was reviewed retrospectively. All infants born at Parkland Memorial Hospital from January 1, 1972 to December 31, 1994, or a total of 259,049 live births, were included. Early-onset (within 3 days) GBS disease rates were compared for each of five observation groups to determine the efficacy of a single dose of aqueous penicillin G 50,000 U for infants weighing 2,000 g or more and 25,000 U for those weighing less than 2,000 g) administered intramuscularly within 1 hour of delivery for prevention of GBS disease. The rates of early-onset GBS disease were compared in five observation groups: A) pre-study, January 1, 1972 to December 3, 1977--no GBS prophylaxis; B) prospective, controlled intervention study, December 4, 1977 to May 31, 1981, including infants who received a single dose of penicillin at birth (group B1) and those who did not (group B2); C) universal penicillin prophylaxis, June 1, 1981 to October 31, 1986; and D) no routine penicillin prophylaxis, November 1, 1986 to December 31, 1994. The incidence of early-onset GBS disease in the penicillin groups (B1, C) was significantly lower than that in the untreated groups (A, B2, D): 0.25 and 0.63 per 1,000 versus 1.59, 1.19, and 1.95 per 1,000, respectively (P < or = .03). The incidence of late-onset GBS disease was unaffected by penicillin prophylaxis, and there was no increase in the incidence of disease caused by penicillin-resistant pathogens or associated mortality in penicillin-treated infants; 2.2 and 2.1 per 1,000 versus 1.6 and 3.3 per 1,000 for disease; 1.0 and 0.5 per 1,000 versus 0.4 and 0.3 per 1,000 for deaths. Universal administration of single-dose penicillin at birth is a safe and effective intervention for the prevention of early-onset GBS disease.

8b Prevention of neonatal septicaemia due to group B streptococci

Group B streptococcus is the leading cause of neonatal septicaemia. Major risk factors for early-onset disease are heavy maternal GBS colonization preterm delivery (and related low birthweight), preterm rupture of membranes, prelabour rupture of membranes, intrapartum fever, GBS urinary infection and low levels of maternal serum anti-GBS antibodies. Screening for maternal GBS colonization, a part of most current preventive strategies, can be targeted on all pregnant women or only on those with recognizable risk factors, and can be implemented antepartum or intrapartum. A culture in a selective broth is the 'gold standard' for detection of GBS colonization. The lower vagina (introitus) is the most suitable site for culturing, with the optional addition of an anorectal sample. The sensitivity of the available rapid GBS antigen tests for vagina samples seems too low to advocate their general use. Intrapartum prophylaxis with ampicillin, preferably targeted on GBS-colonized parturients with risk factors is, at present, the only strategy with established efficacy and safety to prevent early-onset infection. Vaginal chlorhexidine disinfection during labour in all women may, in addition offer a minor contribution to prevention. Late-onset GBS disease is unlikely to be reduced by these strategies. In the future, immunoprophylaxis may well prove to be the most safe and efficacious alternative to prevent GBS septicaemia, irrespective of age of onset, although protection of (very) preterm infants is unlikely.

The natural history of group B streptococcal colonization in the pregnant woman and her offspring: I. Colonization studies

A longitudinal study of colonization by group B streptococcus (GBS) was conducted in 93 pregnant women and 92 of their infants. Positive cultures were obtained from vaginal swab specimens on at least one occasion during pregnancy from 20.4% of the women. Three types of carriage were observed: chronic, transient, and intermittent. At the time of delivery, 12.9% of the mothers were colonized by GBS. GBS colonization occurred in 41.7% of the infants of the mothers colonized intrapartum. Only 1.2% of infants intrapartum culture-negative mothers were colonized. Infants colonized at birth were culture negative by 4 months of age. This study suggests that interruption of vertical transmission of GBS from mother to infant not only would influence the incidence of early-onset GBS disease but also might reduce the incidence of late-onset GBS disease.