Andi L. Shane

Early Onset Neonatal Sepsis: The Burden of Group B Streptococcal and E. coli Disease Continues

BACKGROUND: Guidelines for prevention of group B streptococcal (GBS) infection have successfully reduced early onset (EO) GBS disease. Study results suggest that Escherichia coli is an important EO pathogen. OBJECTIVE: To determine EO infection rates, pathogens, morbidity, and mortality in a national network of neonatal centers. METHODS: Infants with EO infection were identified by prospective surveillance at Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Network centers. Infection was defined by positive culture results for blood and cerebrospinal fluid obtained from infants aged ≤72 hours plus treatment with antibiotic therapy for ≥5 days. Mother and infant characteristics, treatments, and outcomes were studied. Numbers of cases and total live births (LBs) were used to calculate incidence. RESULTS: Among 396 586 LBs (2006–2009), 389 infants developed EO infection (0.98 cases per 1000 LBs). Infection rates increased with decreasing birth weight. GBS (43%, 0.41 per 1000 LBs) and E coli (29%, 0.28 per 1000 LBs) were most frequently isolated. Most infants with GBS were term (73%); 81% with E coli were preterm. Mothers of 67% of infected term and 58% of infected preterm infants were screened for GBS, and results were positive for 25% of those mothers. Only 76% of mothers with GBS colonization received intrapartum chemoprophylaxis. Although 77% of infected infants required intensive care, 20% of term infants were treated in the normal newborn nursery. Sixteen percent of infected infants died, most commonly with E coli infection (33%). CONCLUSION: In the era of intrapartum chemoprophylaxis to reduce GBS, rates of EO infection have declined but reflect a continued burden of disease. GBS remains the most frequent pathogen in term infants, and E coli the most significant pathogen in preterm infants. Missed opportunities for GBS prevention continue. Prevention of E coli sepsis, especially among preterm infants, remains a challenge.

The Burden of Invasive Early-onset Neonatal Sepsis in the United States, 2005–2008

Background: Sepsis in the first 3 days of life is a leading cause of morbidity and mortality among infants. Group B Streptococcus (GBS), historically the primary cause of early-onset sepsis (EOS), has declined through widespread use of intrapartum chemoprophylaxis. We estimated the national burden of invasive EOS cases and deaths in the era of GBS prevention. Methods: Population-based surveillance for invasive EOS was conducted in 4 of the Centers for Disease Control and Preventions Active Bacterial Core surveillance sites from 2005 to 2008. We calculated incidence using state and national live birth files. Estimates of the national number of cases and deaths were calculated, standardizing by race and gestational age. Results: Active Bacterial Core surveillance identified 658 cases of EOS; 72 (10.9%) were fatal. Overall incidence remained stable during the 3 years (2005: 0.77 cases/1000 live births; 2008: 0.76 cases/1000 live births). GBS (∼38%) was the most commonly reported pathogen followed by Escherichia coli (∼24%). Black preterm infants had the highest incidence (5.14 cases/1000 live births) and case fatality (24.4%). Nonblack term infants had the lowest incidence (0.40 cases/1000 live births) and case fatality (1.6%). The estimated national annual burden of EOS was approximately 3320 cases (95% confidence interval [CI]: 3060–3580), including 390 deaths (95% CI: 300–490). Among preterm infants, 1570 cases (95% CI: 1400–1770; 47.3% of the overall) and 360 deaths (95% CI: 280–460; 92.3% of the overall) occurred annually. Conclusions: The burden of invasive EOS remains substantial in the era of GBS prevention and disproportionately affects preterm and black infants. Identification of strategies to prevent preterm births is needed to reduce the neonatal sepsis burden.

Oral Rotavirus Vaccines: How Well Will They Work Where They Are Needed Most?

Rotavirus vaccines hold promise to decrease the burden of severe diarrhea in the poorest countries, where 85% of deaths due to rotavirus occur. However, the potency of live oral vaccines is lower in these challenging settings than in middle- and upper-income countries. Many hypotheses have been suggested to explain these differences that could provide clues to improve the ultimate success of these novel vaccines. Although introduction today of even moderately effective vaccines will decrease the morbidity and mortality associated with rotavirus in low-income settings, research is urgently needed to understand why these differences in efficacy occur and what could be done to improve vaccine performance to maximize the life-saving benefits of vaccination.

Neonatal sepsis: Progress towards improved outcomes

Neonates are predisposed to infections during the perinatal period due to multiple exposures and a relatively compromised immune system. The burden of disease attributed to neonatal infections varies by geographic region and maternal and neonatal risk factors. Worldwide, it is estimated that more than 1.4 million neonatal deaths annually are the consequence of invasive infections. Risk factors for early-onset neonatal sepsis (EOS) include prematurity, immunologic immaturity, maternal Group B streptococcal colonization, prolonged rupture of membranes, and maternal intra-amniotic infection. Intrapartum antimicrobial prophylaxis administered to GBS-colonized women has reduced the burden of disease associated with early onset GBS invasive infections. Active surveillance has identified Gram-negative pathogens as an emerging etiology of early-onset invasive infections. Late-onset neonatal sepsis (LOS) attributable to Gram-positive organisms, including coagulase negative Staphylococci and Staphylococcus aureus, is associated with increased morbidity and mortality among premature infants. Invasive candidiasis is an emerging cause of late-onset sepsis, especially among infants who receive broad spectrum antimicrobial agents. Prophylactic fluconazole administration to very low birthweight (VLBW) neonates during the first 6 weeks of life reduces invasive candidiasis in neonatal intensive care units with high rates of fungal infection. Prevention of healthcare associated infections through antimicrobial stewardship, limited steroid use, early enteral feeding, limited use of invasive devices and standardization of catheter care practices, and meticulous hand hygiene are important and cost-effective strategies for reducing the burden of late-onset neonatal sepsis.

Inhibitory Effect of Breast Milk on Infectivity of Live Oral Rotavirus Vaccines

Background: Live oral rotavirus vaccines have been less immunogenic and efficacious among children in poor developing countries compared with middle income and industrialized countries for reasons that are not yet completely understood. We assessed whether the neutralizing activity of breast milk could lower the titer of vaccine virus and explain this difference in vitro. Methods: Breast milk samples were collected from mothers who were breast-feeding infants 4 to 29 weeks of age (ie, vaccine eligible age) in India (N = 40), Vietnam (N = 77), South Korea (N = 34), and the United States (N = 51). We examined breast milk for rotavirus-specific IgA and neutralizing activity against 3 rotavirus vaccine strains—RV1, RV5 G1, and 116E using enzyme immunoassays. The inhibitory effect of breast milk on RV1 was further examined by a plaque reduction assay. Findings: Breast milk from Indian women had the highest IgA and neutralizing titers against all 3 vaccine strains, while lower but comparable median IgA and neutralizing titers were detected in breast milk from Korean and Vietnamese women, and the lowest titers were seen in American women. Neutralizing activity was greatest against the 2 vaccine strains of human origin, RV1 and 116E. This neutralizing activity in one half of the breast milk specimens from Indian women could reduce the effective titer of RV1 by ∼2 logs, of 116E by 1.5 logs, and RV5 G1 strain by ∼1 log more than that of breast milk from American women. Interpretation: The lower immunogenicity and efficacy of rotavirus vaccines in poor developing countries could be explained, in part, by higher titers of IgA and neutralizing activity in breast milk consumed by their infants at the time of immunization that could effectively reduce the potency of the vaccine. Strategies to overcome this negative effect, such as delaying breast-feeding at the time of immunization, should be evaluated.

Recent developments and current issues in the epidemiology, diagnosis, and management of bacterial and fungal neonatal sepsis.

Identifying neonates with sepsis is complicated by variability in clinical presentation. The incidence of early onset sepsis (EOS) resulting from invasive group B streptococcal (GBS) infections has been notably reduced by the widespread delivery of intrapartum antibiotic prophylaxis. Rates of EOS attributable to non-GBS etiologies have remained constant, and ampicillin-resistant Escherichia coli has become more prevalent. Late-onset sepsis (LOS) attributable to gram-positive organisms including coagulase-negative Staphylococci and Staphylococcus aureus is associated with increased morbidity and mortality among premature infants. Invasive candidiasis is an emerging cause of LOS, especially among infants who receive broad-spectrum antimicrobial agents. Prophylactic fluconazole administration to very low-birth-weight (VLBW) neonates during the first 6 weeks of life prevents invasive candidiasis in neonatal intensive care units (NICU) with high rates of fungal infections. Targeted fluconazole prophylaxis may be beneficial in VLBW neonates who receive care in NICUs with lower rates of invasive fungal infections. Assessment of immune function, neutrophil markers, acute phase reactants, and utilization of sepsis screening scores may contribute to the management of sepsis. Maternal decolonization, antimicrobial stewardship, early enteral feeding, and optimal infection control practices are potential practical strategies for reducing the burden of neonatal sepsis.

Chorioamnionitis and Culture-Confirmed, Early-Onset Neonatal Infections

BACKGROUND: Current guidelines for prevention of neonatal group B streptococcal disease recommend diagnostic evaluations and empirical antibiotic therapy for well-appearing, chorioamnionitis-exposed newborns. Some clinicians question these recommendations, citing the decline in early-onset group B streptococcal disease rates since widespread intrapartum antibiotic prophylaxis implementation and potential antibiotic risks. We aimed to determine whether chorioamnionitis-exposed newborns with culture-confirmed, early-onset infections can be asymptomatic at birth. METHODS: Multicenter, prospective surveillance for early-onset neonatal infections was conducted during 2006–2009. Early-onset infection was defined as isolation of a pathogen from blood or cerebrospinal fluid collected ≤72 hours after birth. Maternal chorioamnionitis was defined by clinical diagnosis in the medical record or by histologic diagnosis by placental pathology. Hospital records of newborns with early-onset infections born to mothers with chorioamnionitis were reviewed retrospectively to determine symptom onset. RESULTS: Early-onset infections were diagnosed in 389 of 396 586 live births, including 232 (60%) chorioamnionitis-exposed newborns. Records for 229 were reviewed; 29 (13%) had no documented symptoms within 6 hours of birth, including 21 (9%) who remained asymptomatic at 72 hours. Intrapartum antibiotic prophylaxis exposure did not differ significantly between asymptomatic and symptomatic infants (76% vs 69%; P = .52). Assuming complete guideline implementation, we estimated that 60 to 1400 newborns would receive diagnostic evaluations and antibiotics for each infected asymptomatic newborn, depending on chorioamnionitis prevalence. CONCLUSIONS: Some infants born to mothers with chorioamnionitis may have no signs of sepsis at birth despite having culture-confirmed infections. Implementation of current clinical guidelines may result in early diagnosis, but large numbers of uninfected asymptomatic infants would be treated.

Methicillin-Resistant and Susceptible Staphylococcus aureus Bacteremia and Meningitis in Preterm Infants

BACKGROUND: Data are limited on the impact of methicillin-resistant Staphylococcus aureus (MRSA) on morbidity and mortality among very low birth weight (VLBW) infants with S aureus (SA) bacteremia and/or meningitis (B/M). METHODS: Neonatal data for VLBW infants (birth weight 401–1500 g) born January 1, 2006, to December 31, 2008, who received care at centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network were collected prospectively. Early-onset (≤72 hours after birth) and late-onset (>72 hours) infections were defined by blood or cerebrospinal fluid cultures and antibiotic treatment of ≥5 days (or death <5 days with intent to treat). Outcomes were compared for infants with MRSA versus methicillin-susceptible S aureus (MSSA) B/M. RESULTS: Of 8444 infants who survived >3 days, 316 (3.7%) had SA B/M. Eighty-eight had MRSA (1% of all infants, 28% of infants with SA); 228 had MSSA (2.7% of all infants, 72% of infants with SA). No infant had both MRSA and MSSA B/M. Ninety-nine percent of MRSA infections were late-onset. The percent of infants with MRSA varied by center (P < .001) with 9 of 20 centers reporting no cases. Need for mechanical ventilation, diagnosis of respiratory distress syndrome, necrotizing enterocolitis, and other morbidities did not differ between infants with MRSA and MSSA. Mortality was high with both MRSA (23 of 88, 26%) and MSSA (55 of 228, 24%). CONCLUSIONS: Few VLBW infants had SA B/M. The 1% with MRSA had morbidity and mortality rates similar to infants with MSSA. Practices should provide equal focus on prevention and management of both MRSA and MSSA infections among VLBW infants.

Reconsidering contact precautions for endemic methicillin-resistant staphylococcus aureus and vancomycin-resistant enterococcus

BACKGROUND Whether contact precautions (CP) are required to control the endemic transmission of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in acute care hospitals is controversial in light of improvements in hand hygiene, MRSA decolonization, environmental cleaning and disinfection, fomite elimination, and chlorhexidine bathing. OBJECTIVE To provide a framework for decision making around use of CP for endemic MRSA and VRE based on a summary of evidence related to use of CP, including impact on patients and patient care processes, and current practices in use of CP for MRSA and VRE in US hospitals. DESIGN A literature review, a survey of Society for Healthcare Epidemiology of America Research Network members on use of CP, and a detailed examination of the experience of a convenience sample of hospitals not using CP for MRSA or VRE. PARTICIPANTS Hospital epidemiologists and infection prevention experts. RESULTS No high quality data support or reject use of CP for endemic MRSA or VRE. Our survey found more than 90% of responding hospitals currently use CP for MRSA and VRE, but approximately 60% are interested in using CP in a different manner. More than 30 US hospitals do not use CP for control of endemic MRSA or VRE. CONCLUSIONS Higher quality research on the benefits and harms of CP in the control of endemic MRSA and VRE is needed. Until more definitive data are available, the use of CP for endemic MRSA or VRE in acute care hospitals should be guided by local needs and resources.

Probiotics in Primary Care Pediatrics

Probiotics are live microorganisms that help stabilize and balance intestinal microflora. Although these organisms are ubiquitous and have been used in the production of foods, probiotics have been used more frequently for therapeutic purposes, including the treatment and prevention of pediatric diseases. This article reviews the proposed mechanisms of the beneficial effects of probiotics, potential uses of these organisms in pediatric care, and promising future directions for their application.