Detection of group B streptococcal bacteremia in simulated intrapartum antimicrobial prophylaxis

The transplacental passage of commonly used intrapartum antibiotics and its impact on the newborn management: A narrative review

Neonates exposed to intra-amniotic infection are at increased risk of early-onset sepsis. Administration of antibiotics to the mother may offer some protection, however a comprehensive description of the determinants influencing their transplacental passage and delivery to the fetus has not been performed. While penicillin G, ampicillin, cefazolin and gentamicin reach therapeutic levels in the fetal serum rapidly following maternal administration, the transfer of second-line intrapartum antimicrobials, such as vancomycin and clindamycin, is slower and less predictable. Erythromycin, used in the context of preterm premature rupture of the membranes, has suboptimal influx into the fetal compartment. This evidence is predominantly drawn from term pregnancies and situations of low infectious risk; however, prematurity may negatively influence fetal exposure to intrapartum antibiotics. Optimal fetal antimicrobial concentrations to target are poorly defined and the extent to which our review findings apply to preterm early-onset neonatal sepsis prevention is unclear. Interpretation of blood cultures drawn in neonates with expected circulating levels of maternal antimicrobials above the minimal inhibitory concentration for Group B Streptococcus is challenging despite the use of contemporary optimized blood culture media.

Maternal intrapartum antibiotic treatment continues to exert a bactericidal effect on the umbilical cord and peripheral venous blood of newborn infants

AIM

It is unclear whether maternal intrapartum antibiotic treatment (IAT) continues to exert a bactericidal effect on common pathogens in neonates. We studied the in vitro bactericidal effect of IAT on the cord and peripheral venous blood of newborn infants.

METHODS

Umbilical cord and peripheral venous blood from newborn infants born at Kaplan Medical Center, Israel, from April to October 2014 were studied for serum bactericidal titres against Group B Streptococcus (GBS) and Escherichia coli (E. coli) strains. We studied 60 samples of umbilical cord blood and 18 samples of peripheral venous blood from 60 newborn infants whose mothers received IAT. The controls were 10 samples of cord blood from mothers without IAT.

RESULTS

Cord blood exerted a bactericidal effect against 98% of GBS isolates but only 8% of E.coli isolates. Peripheral blood exerted a bactericidal effect against GBS in 94% of cases, but not against E. coli. No bactericidal effect was seen in the blood from the controls.

CONCLUSION

We found a continued bactericidal effect of umbilical cord blood and neonatal peripheral blood from newborn infants of IAT-treated mothers, mainly against GBS, but rarely against E. Coli. These findings may assist clinicians treating at-risk infants exposed to IAT.

Prospective surveillance of antibiotic use in the neonatal intensive care unit: results from the SCOUT study

BACKGROUND

Prolonged or unnecessary antibiotic use is associated with adverse outcomes in neonates. Our objectives were to quantify all antibiotic use in a Level-III neonatal intensive care unit and to identify scenarios where their use could be reduced.

METHODS

Surveillance and evaluation of all antibiotic use provided to every infant admitted to a Level-III neonatal intensive care unit from 10/3/11 to 11/30/12 was performed. Types of antibiotics, reasons for their initiation, discontinuation and duration, as well as clinical, laboratory and outcome data were recorded. Antibiotic use was quantified by days of therapy (DOT) per 1000 patient-days (PD).

RESULTS

A total of 1607 infants were included. The total antibiotic use was 9165 DOT (343.2 DOT/1000 PD; 5.7 DOT/infant). Seventy-two percent of infants received 1 (43%) or more (29%) courses of antibiotics. Gentamicin (46%), ampicillin (39%) and oxacillin (8%) were the most frequently used agents. Ninety-four percent of antibiotic use (323 DOT/1000 PD) was empiric therapy for suspected infection. Sixty-three percent (216.2 DOT/1000 PD) was discontinued at approximately 48 hours when cultures were sterile (68%>48 hours, 32%≤48 hours). Twenty-six percent of all antibiotic use (89.4 DOT/1000 PD) was therapy for ≥5 days despite sterile cultures; pneumonia (16%) and "culture-negative" sepsis (8%) were the major contributors. Five percent (17.4 DOT/1000 PD) of antibiotic use was for culture-proven sepsis, 5% (16.6 DOT/1000 PD) was penicillin prophylaxis for group B Streptococcus and 1% (3.5 DOT/1000 PD) was preprocedural prophylaxis.

CONCLUSIONS

Narrow-spectrum therapy accounted for >92% of antibiotic use and would not be monitored by most stewardship programs. Only 5% of antibiotic usage was due to culture-proven infection. Pneumonia and "culture-negative" sepsis were frequent reasons for prolonged therapy; further study of these conditions may allow reduction in treatment duration.

Safety of physical examination alone for managing well-appearing neonates ≥ 35 weeks' gestation at risk for early-onset sepsis

OBJECTIVE

The published data to support recommendations for prevention and management of well-appearing at-risk newborns (WAARNs) for early-onset sepsis (EOS) are limited.

METHODS

Retrospective cohort study comparing two different strategies for managing WAARNs (≥ 35 weeks' gestation) during a 6-year period (Period 1, from 2005 to 2007; Period 2, from 2009 to 2011). WAARNs were defined as healthy-appearing neonates evaluated because of risk factors for EOS. Laboratory evaluation plus simplified physical examination (Period 1) was compared with physical examination alone (PEA, Period 2). The use of antibiotics, the length of stay, the timeliness of diagnosis and the risk of falling ill immediately after hospital discharge in both periods were also compared.

RESULTS

WAARNs receiving empirical antibiotics were 14/500 (Period 1) and 3/500 (Period 2, p = 0.01). Median length of stay was 4 (Period 1) and 3 days (Period 2, p = 0.04). Symptoms of EOS were earlier than laboratory evaluation results in 42/44 neonates. Severe disease was diagnosed within 6 h of life in all neonates. No WAARNs presented with EOS following hospital discharge.

CONCLUSIONS

WAARNs managed through PEA received less unnecessary antibiotics and had a shorter length of stay. They had no increased risk of severe complications or increased risk of becoming ill following hospital discharge.

Role of guidelines on length of therapy in chorioamnionitis and neonatal sepsis

BACKGROUND AND OBJECTIVE

Chorioamnionitis (CAM) is a major risk factor for neonatal sepsis. At our institution, neonates exposed to CAM and intrapartum antibiotics are treated with prolonged antimicrobial therapy if laboratory values are abnormal despite a sterile blood culture. Recently, the Committee on the Fetus and Newborn (COFN) recommended a similar strategy for treating neonates exposed to CAM. Our objective was to determine the frequency of abnormal laboratory parameters in term and late-preterm neonates exposed to CAM and evaluate the implication of recent COFN guidelines.

METHODS

This retrospective data analysis included late-preterm and term neonates exposed to CAM. Laboratory parameters, clinical symptoms and the number of infants treated with prolonged antibiotics were determined.

RESULTS

A total of 554 infants met the inclusion criteria. Eighty-three infants (14.9%) had an abnormal immature to total neutrophil ratio (>0.2) and 121 infants (22%) had an abnormal C-reactive protein level (>1 mg/dL) at 12 hours of age. A total of 153 infants (27.6%) had an abnormal immature to total neutrophil ratio and/or abnormal C-reactive protein level at 12 hours of age. Only 4 (0.7%) of 554 infants had a positive blood culture result. A total of 134 (24.2%) infants were treated with prolonged antibiotics (112 [20.2%] were treated solely based on abnormal laboratory data). Lumbar puncture was performed in 120 (21.6%) infants.

CONCLUSIONS

When managed by using a strategy similar to recent COFN guidelines, a large number of term and late-preterm infants exposed to CAM who had sterile blood culture findings were treated with prolonged antibiotic therapy due to abnormal laboratory findings. They were also subjected to additional invasive procedures and had a longer duration of hospitalization.

Impact of perinatal practices for early-onset group B Streptococcal disease prevention

BACKGROUND

Prevention of residual cases of neonatal group B streptococcus (GBS) early-onset disease (EOGBS) has become a goal in the past decade. This study is aimed at evaluating changes in the incidence of EOGBS over a 9-year period after the implementation of a screening-based approach and comparing 2 different protocols for managing healthy-appearing at-risk newborns (ARNs).

METHODS

A screening-based strategy was introduced in Emilia-Romagna (Italy) in 2003. A prospective, cohort study was conducted from 2003 to 2011; culture-proven EOGBS cases were analyzed in 2 periods: period 1 (2003 to 2008) and period 2 (2009 to 2011). ARNs (≥35 weeks' gestation) were managed according to 2 different protocols: laboratory testing plus observation (period 1) was replaced with expectant observation alone (period 2).

RESULTS

Ninety-one EOGBS cases were observed (incidence rate: 0.26/1000 live births). The incidence in full-term babies declined from 0.30 (period 1) to 0.14/1000 live births (period 2, P = 0.04). Recto-vaginal screening cultures in full-term mothers increased significantly from 10/45 (period 1) to 10/14 (period 2, P = 0.002). EOGBS was diagnosed earlier in ARNs than in not-at-risk newborns (mean age 5.5 versus 14.5 hours, P = 0.007). There were no differences in age at diagnosis irrespective of whether ARNs were managed with laboratory testing plus observation (mean 3.5 hours, period 1) or with expectant observation alone (mean 2.4 hours, period 2).

CONCLUSIONS

When screening cultures were handled according to standard protocols, cases of EOGBS in full-term newborns simultaneously decreased. ARNs were diagnosed in a timely manner through both strategies. The clinical yield of laboratory testing was negligible.

Policy statement—Recommendations for the prevention of perinatal group B streptococcal (GBS) disease

The Centers for Disease Control and Prevention (CDC) guidelines for the prevention of perinatal group B streptococcal (GBS) disease were initially published in 1996. The American Academy of Pediatrics (AAP) also published a policy statement on this topic in 1997. In 2002, the CDC published revised guidelines that recommended universal antenatal GBS screening; the AAP endorsed these guidelines and published recommendations based on them in the 2003 Red Book. Since then, the incidence of early-onset GBS disease in neonates has decreased by an estimated 80%. However, in 2010, GBS disease remained the leading cause of early-onset neonatal sepsis. The CDC issued revised guidelines in 2010 based on evaluation of data generated after 2002. These revised and comprehensive guidelines, which have been endorsed by the AAP, reaffirm the major prevention strategy--universal antenatal GBS screening and intrapartum antibiotic prophylaxis for culture-positive and high-risk women--and include new recommendations for laboratory methods for identification of GBS colonization during pregnancy, algorithms for screening and intrapartum prophylaxis for women with preterm labor and premature rupture of membranes, updated prophylaxis recommendations for women with a penicillin allergy, and a revised algorithm for the care of newborn infants. The purpose of this policy statement is to review and discuss the differences between the 2002 and 2010 CDC guidelines that are most relevant for the practice of pediatrics.

C-Reactive Protein, Detected with a Highly Sensitive Assay, in Non-Infected Newborns and Those with Early Onset Infection

SUMMARY: BACKGOUND: The aim of this study was to investigate C-reactive protein (CRP), measured by a highly sensitive method (hsCRP) in non-infected newborns and in those with suspected early onset bacterial infection (EOBI) as well as to test whether EOBI would be detectable earlier by hsCRP than by a nephelometric CRP (nsCRP) assay (thresholds > 10 mg/l) or IL-8. PATIENTS AND METHODS: 106 neonates with signs of infection comprised the suspected EOBI group. 134 neonates with risk factors but confirmed exclusion of EOBI served as non-infected controls. RESULTS: In the non-infected group, hsCRP in the first 6 h after birth was low (0.7 mg/l; SD 0.16 mg/l) but showed an increase to 4.11 mg/l (SD 3.33 mg/l) at 72 h (p < 0.001 vs. 6 h). The sensitivity of hsCRP (cut-off 0.3 mg/l) vs. nsCRP for EOBI was 0.46 vs. 0.23 at 6 h after clinical suspicion. Of all parameters measured, IL-8 had the highest sensitivity and specificity to detect EOBI at 6 h (0.60 and 0.90), but declined after 12 and 24 h. CONCLUSION: Lowering the CRP detection threshold by a highly sensitive assay did not improve diagnostic accuracy for EOBI.

In vitro evaluation of three bacterial culture systems for the recovery of Escherichia coli from equine blood

OBJECTIVE

To evaluate the effectiveness of a commercial conventional blood culture system (BCS), a commercial resin-containing BCS, and a commercial lysis-centrifugation-based BCS for the recovery of Escherichia coli from equine blood samples inoculated with that organism.

SAMPLE POPULATION

Samples of blood obtained from a clinically normal horse that were inoculated with E coli.

PROCEDURES

Blood samples were aseptically collected and inoculated with an E coli specimen (50 CFUs/mL) that had been previously isolated from a foal with sepsis. Subsequently, samples were spiked with gentamicin at a concentration of 30 mug/mL, and 10 mL of each mixture was inoculated into 1 bottle or tube of each BCS. Samples were processed and incubated according to the manufacturer's guidelines and inoculated onto 5% sheep blood agar plates. Plated samples were examined macroscopically at regular intervals for as long as 72 hours. Detection of E coli and time to detection were recorded for each medium.

RESULTS

Detection frequency of E coli was significantly greater by use of the resin-containing BCS (14/23 bottles) than that achieved by use of the conventional BCS (7/23 bottles) or the lysis-centrifugation-based BCS (0/10 tubes). Mean detection time (6 hours after plating) did not differ between the BCS with conventional medium and the BCS with resincontaining medium.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that a BCS with resin-containing medium may provide clinical benefit in the successful recovery of E coli from the blood of foals with sepsis that have been previously administered gentamicin.

Lipopolysaccharide-binding protein in noninfected neonates and those with suspected early-onset bacterial infection

OBJECTIVES

To investigate postnatal lipopolysaccharide-binding protein (LBP) kinetics in term neonates and to test its diagnostic accuracy for early-onset bacterial infection (EOBI).

STUDY DESIGN

A total of 99 neonates with clinical and serological signs of EOBI comprised the study group; 198 neonates with risk factors, but without EOBI, served as controls. LBP, C-reactive protein (CRP) and interleukin-8 (IL-8) were determined.

RESULTS

LBP in the noninfected group increased until 24 h after birth (P < 0.05 vs 6 h). LBP and CRP correlated strongly in neonates with suspected EOBI (r = 0.63). Although LBP reached a higher sensitivity than CRP 6 and 12 h after clinical suspicion (45 (24-68) and 79% (54-94) vs 9 (0-24) and 39% (17-64); P < 0.05)), EOBI was most reliably detected by IL-8.

CONCLUSION

LBP kinetics were age-dependent. LBP was not sufficiently sensitive in the prediction of EOBI.

Evaluation of IL-8-concentrations in plasma and lysed EDTA-blood in healthy neonates and those with suspected early onset bacterial infection

Plasma IL-8 is a diagnostic parameter of early-onset bacterial infection (EOBI) in neonates but has a short half-life. The detergent-lysed whole-blood (DLWB) IL-8 consists of both extracellular and cell-bound IL-8. The objective of this study was to investigate kinetics of plasma and DLWB IL-8 in healthy newborns and those with suspected EOBI and to test the hypothesis that determination of DLWB IL-8 results in higher sensitivity for EOBI detection. Sixty-one neonates with clinical and serologic signs of EOBI composed the study group; 188 neonates with risk factors but without EOBI served as control subjects. IL-8 concentrations were determined in plasma and DLWB. In the control group, DLWB IL-8 concentrations were 280-fold higher (9599 pg/mL; SD 4433) up to 24 h post partum than corresponding plasma levels (34.2 pg/mL; SD 18.1). The sensitivity of DLWB versus plasma IL-8 for EOBI was 0.97 versus 0.71 after 6 h and 0.70 versus 0.32 after 24 h. Corresponding values for specificity were 0.95 versus 0.90 after 6 h and 0.92 versus 0.99 after 24 h. After 24 h, the negative predictive value for DLWB versus plasma IL-8 was 0.80 versus 0.66. DLWB IL-8 showed a higher sensitivity for EOBI within 6 h after first clinical suspicion than plasma IL-8. It also remained elevated longer. Our results suggest that DLWB IL-8 results in a higher sensitivity for EOBI.