Neonatal sepsis resulting from possible amniotic fluid infection: risk and detection

Vignettes Identify Variation in Antibiotic Use for Suspected Early Onset Sepsis

BACKGROUND AND OBJECTIVES

There is widespread unwarranted antibiotic use and large individual provider variation in antibiotic use in NICUs. Vignette-based research methodology offers a unique method of studying variation in individual provider decisions. The objective with this study was to use a vignette-based survey to identify specific areas of provider antibiotic use variation in newborns being evaluated for early onset sepsis.

METHODS

This study was undertaken as part of a statewide multicenter neonatal antibiotic stewardship quality improvement project led by a perinatal quality improvement collaborative. A web-based vignette survey was administered to identify variation in decisions to start and discontinue antibiotics in cases of early onset sepsis.

RESULTS

The largest variation was noted in 3 of the 6 vignette cases. These cases highlighted variation in (1) decisions to start antibiotics in a case describing a well-appearing newborn with risk factors and an elevated C-reactive protein, (2) decisions to start antibiotics in the case of a newborn with risk factors plus mild respiratory signs at birth, and (3) decisions to stop antibiotics in the case of the newborn with a history of sepsis risk factors and mild clinical respiratory signs that resolved after 72 hours.

CONCLUSIONS

Clinical vignette assessment identified specific areas of variation in individual provider antibiotic use decisions in cases of suspected early onset sepsis. Vignettes are a valuable method of describing individual provider variation and highlighting antibiotic stewardship improvement opportunities in NICUs.

Prevalence of early-onset neonatal infection among newborns of mothers with bacterial infection or colonization: a systematic review and meta-analysis

BACKGROUND

Although neonatal infections cause a significant proportion of deaths in the first week of life, little is known about the burden of neonatal disease originating from maternal infection or colonization globally. This paper describes the prevalence of vertical transmission--the percentage of newborns with neonatal infection among newborns exposed to maternal infection.

METHODS

We searched Pubmed, Embase, Scopus, Web of Science, Cochrane Library, and WHO Regional Databases for studies of maternal infection, vertical transmission, and neonatal infection. Studies that measured prevalence of bacterial vertical transmission were included. Random effects meta-analyses were used to pool data to calculate prevalence estimates of vertical transmission.

RESULTS

122 studies met the inclusion criteria. Only seven studies (5.7%) were from very high neonatal mortality settings. Considerable heterogeneity existed between studies given the various definitions of infection (lab-confirmed, clinical signs), colonization, and risk factors of infection. The prevalence of early onset neonatal lab-confirmed infection among newborns of mothers with lab-confirmed infection was 17.2% (95%CI 6.5-27.9). The prevalence of neonatal lab-confirmed infection among newborns of colonized mothers was 0% (95% CI 0.0-0.0). The prevalence of neonatal surface colonization among newborns of colonized mothers ranged from 30.9-45.5% depending on the organism. The prevalence of neonatal lab-confirmed infection among newborns of mothers with risk factors (premature rupture of membranes, preterm premature rupture of membranes, prolonged rupture of membranes) ranged from 2.9-19.2% depending on the risk factor.

CONCLUSIONS

The prevalence of early-onset neonatal infection is high among newborns of mothers with infection or risk factors for infection. More high quality studies are needed particularly in high neonatal mortality settings to accurately estimate the prevalence of early-onset infection among newborns at risk.

Preventing early-onset group B streptococcal sepsis: strategy development using decision analysis

OBJECTIVE

To evaluate recommended strategies for prevention of early-onset group B streptococcal infections (EOGBS) with reference to strategies optimized using decision analysis.

METHODS

The EOGBS attack rate, prevalence and odds ratios for risk factors, and expected effects of prophylaxis were estimated from published data. Population subgroups were defined by gestational age, presence or absence of intrapartum fever or prolonged rupture of membranes, and presence or absence of maternal group B streptococcus (GBS) colonization. The EOGBS prevalence in each subgroup was estimated using decision analysis. The number of EOGBS cases prevented by an intervention was estimated as the product of the expected reduction in attack rate and the number of expected cases in each group selected for treatment. For each strategy, the number of residual EOGBS cases, cost, and numbers of treated patients were calculated based on the composition of the prophylaxis group. Integrated obstetrical-neonatal strategies for EOGBS prevention were developed by targeting the subgroups expected to benefit most from intervention.

RESULTS

Reductions in EOGBS rates predicted by this decision analysis were smaller than those previously estimated for the strategies proposed by the American Academy of Pediatrics in 1992 (32.9% vs 90.7%), the American College of Obstetricians and Gynecologists in 1992 (53.8% vs 88.8%), and the Centers for Disease Control and Prevention in 1996 (75.1% vs 86.0%). Strategies based on screening for GBS colonization with rectovaginal cultures at 36 weeks or on use of a rapid test to screen for GBS colonization on presentation for delivery, combining intrapartum prophylaxis for selected mothers and postpartum prophylaxis for some of their infants, would require treatment of fewer patients and prevent more cases (78.4% or 80.1%, respectively) at lower cost.

CONCLUSIONS

No strategy can prevent all EOGBS cases, but the attack rate can be reduced at a cost <$12 000 per prevented case. Supplementing intrapartum prophylaxis with postpartum ampicillin in a few infants is more effective and less costly than providing intrapartum prophylaxis for more mothers. Better intrapartum screening tests offer the greatest promise for increasing efficacy. Integrated obstetrical and neonatal regimens appropriate to the population served should be adopted by each obstetrical service. Surveillance of costs, complications, and benefits will be essential to guide continued iterative improvement of these strategies.

Reproductive history and the risk of neonatal sepsis

It was recently suggested that a previous abortion increases the risk of intrapartum infection in a following pregnancy. The authors hypothesised that abortion also could be associated with a higher risk of neonatal sepsis. A case-control study of neonatal sepsis was conducted using the Washington State Birth Registry. Cases of sepsis were selected among singleton livebirths during the period 1984-90, and compared with a control group for the occurrence of spontaneous or induced abortion in previous pregnancies. The risk estimates were calculated using a stratified analysis. After exclusion of primigravidae, the age-adjusted odds ratio (OR) was 1.68, with a 95% confidence interval (CI) 1.33, 2.11 for previous spontaneous abortion, and 2.20 (95% CI 1.73, 2.79) for induced abortion, compared with previous livebirth. After exclusion of nulliparous women, the OR decreased to 1.19 (95% CI 0.90, 1.58) for spontaneous abortion and 1.45 (95% CI 1.03, 2.04) for induced abortion. After controlling for the effect of parity, induced abortion is associated with an increased risk of neonatal sepsis in a subsequent pregnancy, but the association between spontaneous abortion and sepsis is small and non-significant. The authors suggest that the procedures involved in a therapeutic abortion might produce a latent, sub-clinical infection that persists until the next pregnancy, and is then transmitted to the newborn.

The value of C-reactive protein measurement in the diagnosis of neonatal infection

We examined whether serum C-reactive protein (CRP) measurements used in conjunction with leucocyte counts help in the diagnosis of perinatally acquired and nosocomial infections in very preterm newborn infants. One hundred and twenty-five infants born at a gestational age between 23 and 31 weeks with respiratory distress were studied at birth. A similar group of 85 infants beyond 3 days of age were also studied on 100 occasions for suspected infection. The diagnosis of proven or probable infection was correlated with abnormal haematology (leucopenia less than 5000/mm3, leucocytosis greater than 20,000/mm3 or ratio of immature forms to total neutrophils of greater than 0.2) and an elevated CRP (greater than 10 mg/L) singly or in combination. The sensitivity of an elevated CRP was relatively higher than abnormal haematology in both early and late infections and the sensitivity was highest when either test was abnormal. Similarly, the specificity, positive and negative predictive values and efficiency of an elevated CRP was relatively higher than abnormal haematology. The performance of the tests in 45 infants born at 23-28 weeks gestation was similar to that in 80 infants born at 29-31 weeks gestation. It was concluded that both CRP and leucocyte counts should be determined as they provide valuable information in the diagnosis of neonatal bacterial infection.