Antibiotic Safety and Effectiveness in Premature Infants With Complicated Intraabdominal Infections

Neonatal Necrotizing Enterocolitis: An Update on Pathophysiology, Treatment, and Prevention

Necrotizing enterocolitis (NEC) is a life-threatening disease predominantly affecting premature and very low birth weight infants resulting in inflammation and necrosis of the small bowel and colon and potentially leading to sepsis, peritonitis, perforation, and death. Numerous research efforts have been made to better understand, treat, and prevent NEC. This review explores a variety of factors involved in the pathogenesis of NEC (prematurity, low birth weight, lack of human breast milk exposure, alterations to the microbiota, maternal and environmental factors, and intestinal ischemia) and reports treatment modalities surrounding NEC, including pain medications and common antibiotic combinations, the rationale for these combinations, and recent antibiotic stewardship approaches surrounding NEC treatment. This review also highlights the effect of early antibiotic exposure, infections, proton pump inhibitors (PPIs), and H2 receptor antagonists on the microbiota and how these risk factors can increase the chances of NEC. Finally, modern prevention strategies including the use of human breast milk and standardized feeding regimens are discussed, as well as promising new preventative and treatment options for NEC including probiotics and stem cell therapy.

Necrotizing Enterocolitis in Very Low Birth Weight Neonates: A Natural History Study

OBJECTIVE

We characterize the most recent natural history of necrotizing enterocolitis (NEC), as this is an essential first step in guiding the prevention and treatment of this disease in the present day.

STUDY DESIGN

We performed a retrospective cohort study of neonates who were born at 23 to 29 weeks' gestation and birth weight <1,500 g who received care from the Pediatrix Medical Group between 2004 and 2019. We assessed the incidence of medical and surgical NEC and the patterns of initial antibiotic treatment to develop a contemporary cohort for further analysis. Among patients discharged between 2015 and 2019, we characterized the stage-specific risk factors for patients diagnosed with medical or surgical NEC, as well as patterns of disease onset, progression, biomarkers, and outcomes. We used the same approach to characterize patients diagnosed with suspected NEC.

RESULTS

Among 34,032 patients in the contemporary cohort, 1,150 (3.4%) were diagnosed with medical NEC and 543 (1.6%) were diagnosed with surgical NEC. The temporal pattern of disease onset was different for medical and surgical NEC, with gestational age- and birth weight-specific risk disparities emerging earlier in surgical NEC. Thirty-day mortality was much greater among surgical NEC patients (medical NEC 16.4% vs. surgical NEC 43.0%), as were rates of various in-hospital and long-term outcomes. Suspected NEC was diagnosed in 1,256 (3.7%) patients, among whom risk factors and disease onset, progression, and outcomes closely resembled those of medical NEC.

CONCLUSION

Analyzing data from a contemporary cohort enabled us to characterize the current, stage-specific natural history of NEC, including novel insights into suspected NEC. Future studies could leverage this cohort to characterize how specific patient characteristics, care processes, or biomarkers may influence or predict disease outcomes.

KEY POINTS

· The incidence of NEC has reached a stable baseline in recent years.. · Risk factors for NEC vary in a stage-specific manner.. · The stage-specific onset and progression of NEC differ by gestational age and birth weight..

Wide use of broad-spectrum antibiotics in very low birth weight infants with spontaneous focal intestinal perforation-is it really justified?

PURPOSE

Very low birth weight (VLBW) infants are at a risk of spontaneous focal intestinal perforation (FIP). Treatment includes supportive care, antibiotics, and drainage with/without surgery. Broad-spectrum antibiotic agents like carbapenems are applied frequently, although their use is not well-supported by the limited evidence of causal pathogens. We hypothesize that the use of carbapenems may not be necessary in VLBW infants with FIP. Our primary objective was to evaluate the antimicrobial use in VLBW infants with FIP in a cohort of the German Neonatal Network (GNN). The secondary objective was to characterize a subset in detail as a benchmark for future targets of stewardship.

METHODS

Data on VLBW infants with FIP was collected prospectively within the GNN, a collaboration of 68 neonatal intensive care units (NICU). With regards to the primary objective, patient characteristics and antimicrobial treatment were extracted from the predefined GNN database. To address our secondary objective, an additional on-site assessment of laboratory and microbiological culture results were performed.

RESULTS

In the GNN cohort, 613/21,646 enrolled infants (2.8%) developed FIP requiring surgery. They were frequently treated with carbapenems (500/613 (81.6%)) and vancomycin (497/613 (81.1%)). In a subset of 124 VLBW infants, 77 (72.6%) had proof of gram-positive bacteria in the abdominal cavity, coagulase-negative staphylococci (CoNS) predominantly. Despite the low prevalence of gram-negative bacteria (n = 6 (4.8%)), the combination of meropenem and vancomycin was prescribed most frequently (n = 96 (78.0%)).

CONCLUSION

The use of carbapenems as broad-spectrum antimicrobials agents might not be justified in most VLBW infants with FIP. Knowledge on the development of the neonatal gut microbiota, local resistance patterns and individual microbiological findings should be taken into consideration when implementing antimicrobial stewardship programs (ASPs).

Opportunistic dried blood spot sampling validates and optimizes a pediatric population pharmacokinetic model of metronidazole

Pharmacokinetic models rarely undergo external validation in vulnerable populations such as critically ill infants, thereby limiting the accuracy, efficacy, and safety of model-informed dosing in real-world settings. Here, we describe an opportunistic approach using dried blood spots (DBS) to evaluate a population pharmacokinetic model of metronidazole in critically ill preterm infants of gestational age (GA) ≤31 weeks from the Metronidazole Pharmacokinetics in Premature Infants (PTN_METRO, NCT01222585) study. First, we used linear correlation to compare 42 paired DBS and plasma metronidazole concentrations from 21 preterm infants [mean (SD): post natal age 28.0 (21.7) days, GA 26.3 (2.4) weeks]. Using the resulting predictive equation, we estimated plasma metronidazole concentrations (ePlasma) from 399 DBS collected from 122 preterm and term infants [mean (SD): post natal age 16.7 (15.8) days, GA 31.4 (5.1) weeks] from the Antibiotic Safety in Infants with Complicated Intra-Abdominal Infections (SCAMP, NCT01994993) trial. When evaluating the PTN_METRO model using ePlasma from the SCAMP trial, we found that the model generally predicted ePlasma well in preterm infants with GA ≤31 weeks. When including ePlasma from term and preterm infants with GA >31 weeks, the model was optimized using a sigmoidal Emax maturation function of postmenstrual age on clearance and estimated the exponent of weight on volume of distribution. The optimized model supports existing dosing guidelines and adds new data to support a 6-hour dosing interval for infants with postmenstrual age >40 weeks. Using an opportunistic DBS to externally validate and optimize a metronidazole population pharmacokinetic model was feasible and useful in this vulnerable population.

Neonatal complicated intraabdominal infection

PURPOSE OF REVIEW

The purpose of this review is to summarize the treatment of complicated intraabdominal infections (cIAIs) in premature infants.

RECENT FINDINGS

Recent work has continued to define the complex nature of cIAIs and necrotizing enterocolitis (NEC). This includes new findings on the microbiome, breast milk and risk factors associated with NEC. The treatment of cIAIs employs a combination of both surgical and medical treatment. Further look at what type and timing of surgical intervention is used as well as the ideal antibiotic regimen. Upcoming research is highlighted in future directions of NEC treatment.

SUMMARY

cIAIs in premature infants is a challenging disease with more research needed to further delineate the pathophysiology and treatment options.

Antibiotic therapy and necrotizing enterocolitis

Antibiotic therapy remains a cornerstone of treatment of both medical and surgical presentations of necrotizing enterocolitis (NEC). However, guidelines regarding the administration of antibiotics for the treatment of NEC are lacking and practices vary amongst clinicians. Although the pathogenesis of NEC is unknown, there is consensus that the infant gastrointestinal microbiome contributes to the disease. The presumed connection between dysbiosis and NEC has prompted some to study whether early prophylactic enteral antibiotics can prevent NEC. Yet others have taken an opposing approach, studying whether perinatal antibiotic exposure increases the risk of NEC by inducing a state of dysbiosis. This narrative review summarizes what is known about antibiotics and their association with the infant microbiome and NEC, current antibiotic prescribing practices for infants with medical and surgical NEC, as well as potential strategies to further optimize the use of antibiotics in this population of infants.

Standardizing the Evaluation and Management of Necrotizing Enterocolitis in a Level IV NICU

OBJECTIVES

Necrotizing enterocolitis (NEC) is a severe intestinal inflammatory disease and a leading cause of morbidity and mortality in NICUs. Management of NEC is variable because of the lack of evidence-based recommendations. It is widely accepted that standardization of patient care leads to improved outcomes. This quality improvement project aimed to decrease variation in the evaluation and management of NEC in a Level IV NICU.

METHODS

A multidisciplinary team investigated institutional variation in NEC management and developed a standardized guideline and electronic medical record tools to assist in evaluation and management. Retrospective baseline data were collected for 2 years previously and prospectively for 3.5 years after interventions. Outcomes included the ratio of observed-to-expected days of antibiotics and nil per os (NPO) on the basis of the novel guidelines and the percentage of cases treated with piperacillin/tazobactam. Balancing measures were death, surgery, and antifungal use.

RESULTS

Over 5.5 years, there were 124 evaluations for NEC. Special cause variation was noted in the observed-to-expected antibiotic and NPO days ratios, decreasing from 1.94 to 1.18 and 1.69 to 1.14, respectively. Piperacillin/tazobactam utilization increased from 30% to 91%. There were no increases in antifungal use, surgery, or death.

CONCLUSIONS

Variation in evaluation and management of NEC decreased after initiation of a guideline and supporting electronic medical record tools, with fewer antibiotic and NPO days without an increase in morbidity or mortality. A quality improvement approach can benefit patients and decrease variability, even in diseases with limited evidence-based standards.