Neonatal Sepsis of Early Onset, and Hospital-Acquired and Community-Acquired Late Onset: A Prospective Population-Based Cohort Study

Determinants and Outcome of Community-Acquired Late-Onset Neonatal Sepsis in Rural Bangladesh

Background. This study examined the sociodemographic as well as other determinants and outcome of community-acquired late-onset neonatal sepsis (LONS) in rural Bangladesh at Matlab. Methods. In this retrospective chart review, we used an unmatched case-control design (1:2 ratio) to evaluate the factors associated with LONS and their outcomes among babies admitted to the neonatal ward of Matlab Hospital of icddr,b, from January 2012 to December 2014. Neonates presenting with any of the clinical signs of serious bacterial infection during 3 to 28 days of life constituted the cases (LONS), and those without LONS constituted the controls. All the data were retrieved from the electronic databases of Matlab Hospital and Matlab Health and Demographic Surveillance System. Results. Among 1482 admitted neonates, 202 were cases and 404 were randomly selected controls. In babies with LONS, case fatality rate (1% vs 0%, P = .037), duration of inpatient stay (4 days vs 2 days, P < .001), and referral to higher center (9% vs 5%, P = .020) were higher. In an adjusted model, undernutrition (weight for length Z score < −2; odds ratio [OR] = 1.8, 95% confidence interval [CI] = 1.2-2.94), admission in winter season (OR = 1.62, 95% CI = 1.09-2.41), mother’s schooling <10 years (OR = 1.76, 95% CI = 1.09-2.85), primiparity (OR = 1.55, 95% CI = 1.05-2.29), home delivery (OR = 1.87, 95% CI = 1.07-3.26), and household food insecurity (OR = 2.78, 95% CI = 1.31-5.88) were found to be independently associated with LONS. Conclusion. LONS posed considerable socioeconomic burden to the rural community. Further studies are required to consolidate our findings.

Strategies to improve antibiotic use in the neonatal ICU

PURPOSE OF REVIEW

Neonates are at a high risk of infection and may have nonspecific signs of sepsis. Accordingly, they are heavily exposed to antimicrobials. Neonates are also uniquely at risk of both short-term and long-term complications from antibiotic exposure. This review discusses advances in antibiotic stewardship in the neonatal population.

RECENT FINDINGS

Antimicrobial utilization is highly variable among NICUs in excess of case-mix variation. Rates of early-onset sepsis because of Group B Streptococcus have decreased substantially with the introduction of intrapartum antibiotic prophylaxis. Recent epidemiologic studies have created evidence-based tools to more accurately estimate a newborn's risk of early-onset sepsis. Antibiotic selection and duration for late-onset sepsis and necrotizing enterocolitis are variable among centers, with inadequate evidence to guide practice. Novel diagnostic methods and biomarkers are increasingly used to assist with diagnosing infection, but inadequate specificity in many cases may result in excess antibiotic exposure. Published antimicrobial stewardship experiences in the neonatal inpatient setting have largely been successful and well tolerated.

SUMMARY

Recent publications have identified many ways to safely reduce antimicrobial exposure and developed strategies to implement antimicrobial stewardship in the neonatal inpatient setting. However, new approaches are needed to further improve antibiotic use and to implement these interventions more universally in NICUs.

IRF5 Is a Key Regulator of Macrophage Response to Lipopolysaccharide in Newborns

Infections are a leading cause of mortality and morbidity in newborns. The high susceptibility of newborns to infection has been associated with a limited capacity to mount protective immune responses. Monocytes and macrophages are involved in the initiation, amplification, and termination of immune responses. Depending on cues received from their environment, monocytes differentiate into M1 or M2 macrophages with proinflammatory or anti-inflammatory and tissue repair properties, respectively. The purpose of this study was to characterize differences in monocyte to macrophage differentiation and polarization between newborns and adults. Monocytes from umbilical cord blood of healthy term newborns and from peripheral blood of adult healthy subjects were exposed to GM-CSF or M-CSF to induce M1 or M2 macrophages. Newborn monocytes differentiated into M1 and M2 macrophages with similar morphology and expression of differentiation/polarization markers as adult monocytes, with the exception of CD163 that was expressed at sevenfold higher levels in newborn compared to adult M1 macrophages. Upon TLR4 stimulation, newborn M1 macrophages produced threefold to sixfold lower levels of TNF than adult macrophages, while production of IL-1-β, IL-6, IL-8, IL-10, and IL-23 was at similar levels as in adults. Nuclear levels of IRF5, a transcription factor involved in M1 polarization, were markedly reduced in newborns, whereas the NF-κB and MAP kinase pathways were not altered. In line with a functional role for IRF5, adenoviral-mediated IRF5 overexpression in newborn M1 macrophages restored lipopolysaccharide-induced TNF production. Altogether, these data highlight a distinct immune response of newborn macrophages and identify IRF5 as a key regulator of macrophage TNF response in newborns.

Culture-Negative Early-Onset Neonatal Sepsis - At the Crossroad Between Efficient Sepsis Care and Antimicrobial Stewardship

Sepsis is a leading cause of mortality and morbidity in neonates. Presenting clinical symptoms are unspecific. Sensitivity and positive predictive value of biomarkers at onset of symptoms are suboptimal. Clinical suspicion therefore frequently leads to empirical antibiotic therapy in uninfected infants. The incidence of culture confirmed early-onset sepsis is rather low, around 0.4-0.8/1000 term infants in high-income countries. Six to 16 times more infants receive therapy for culture-negative sepsis in the absence of a positive blood culture. Thus, culture-negative sepsis contributes to high antibiotic consumption in neonatal units. Antibiotics may be life-saving for the few infants who are truly infected. However, overuse of broad-spectrum antibiotics increases colonization with antibiotic resistant bacteria. Antibiotic therapy also induces perturbations of the non-resilient early life microbiota with potentially long lasting negative impact on the individual's own health. Currently there is no uniform consensus definition for neonatal sepsis. This leads to variations in management. Two factors may reduce the number of culture-negative sepsis cases. First, obtaining adequate blood cultures (0.5-1 mL) at symptom onset is mandatory. Unless there is a strong clinical or biochemical indication to prolong antibiotics physician need to trust the culture results and to stop antibiotics for suspected sepsis within 36-48 h. Secondly, an international robust and pragmatic neonatal sepsis definition is urgently needed. Neonatal sepsis is a dynamic condition. Rigorous evaluation of clinical symptoms ("organ dysfunction") over 36-48 h in combination with appropriately selected biomarkers ("dysregulated host response") may be used to support or refute a sepsis diagnosis.