Double blind, randomised, placebo controlled study of oral vancomycin in prevention of necrotising enterocolitis in preterm, very low birthweight infants

New concepts in necrotizing enterocolitis

Necrotizing enterocolitis is an overwhelming gastrointestinal emergency that primarily afflicts premature infants born weighing less than 1500 g. Despite years of investigation, the etiology remains unclear, and accepted prevention and treatment strategies are lacking. Studies published over the last year have provided new insight into several aspects of this complex disease. In this review, novel information is presented on (1) the epidemiology; (2) methods of early diagnosis, such as abdominal magnetic resonance imaging; (3) the importance of risk factors, including assessment of feeding strategies and role of bacterial colonization; (4) the pathophysiology, highlighting experimental and clinical trials evaluating the role of inflammatory mediators and growth factors on the disease; (5) preventive strategies, such as anaerobic bacterial supplementation; and (6) surgical interventions, including peritoneal drainage. Understanding some of these important aspects of necrotizing enterocolitis may help improve the outlook of patients with this dreaded disease. Although the incidence of neonatal necrotizing enterocolitis (NEC) and the mortality stemming from this disease have not significantly improved over the last 30 years, there is exciting new information that may significantly improve the outlook of patients with this overwhelming intestinal emergency in the near future.

Necrotiserende enterocolitis

Necrotiserende enterocolitis (nec) is een zeer ernstig verlopende ziekte van het darmkanaal. De incidentie van nec op de neonatale intensive care varieert van 1 tot 5%. De etiologie van nec is onbekend, maar er zijn aanwijzingen dat multipele factoren in staat zijn nec te veroorzaken via activatie van ontstekingsmediatoren, waarvan plaatjesactiverende factor (paf) één van de belangrijkste is. De geactiveerde cascade resulteert uiteindelijk in ontsteking en necrose van de darm. Prematuriteit is de belangrijkste risicofactor voor nec. Andere risicofactoren zijn infectie, ischemie van de darm en blootstelling aan enterale voeding. nec treedt het meest op bij extreem prematuren en prematuren met een groeiachterstand (gewicht minder dan de 10e percentiel). nec kent een ernstig beloop en uiteindelijk overlijdt 30% van de patiënten. Ondanks dat diverse preventiestrategieën bekend zijn, is men niet in staat nec te elimineren. In de toekomst zijn nieuwe ontwikkelingen te verwachten op het gebied van ontstekingsmediatoren.

Necrotizing enterocolitis in infants with very low birth weight

Necrotizing enterocolitis (NEC) is a disease in which the primary risk factor is prematurity. Despite, and partially as a result of, the tremendous strides neonatal care has taken, it is a major cause of morbidity and mortality of the newborn. The infant with very low birth weight is particularly susceptible, and the management of the condition in this group differs somewhat from other neonates. The outcomes continue to improve, but there are significant sequelae. Prevention, which would be the best "cure," is elusive, in no small part because of the multifactorial nature of the etiology of NEC.

Enteral antibiotics for preventing necrotising enterocolitis in low birthweight or preterm infants

BACKGROUND

Necrotising enterocolitis continues to be a problem, particularly in preterm neonates. There have been reports published suggesting that the use of enteral antibiotics may be effective as prophylaxis. This systematic review was undertaken to clarify the issue.

OBJECTIVES

To evaluate the benefits and harms of enteral antibiotic prophylaxis for necrotising enterocolitis in low birth weight and preterm infants.

SEARCH STRATEGY

Searches were made of the Oxford Database of Perinatal trials, MEDLINE (search terms: necrotizing enterocolitis, antibiotics;

LIMITS

newborn infant), previous reviews with cross references, abstracts, conference and symposia proceedings, expert informants and journal handsearching in the fields of Neonatal Pediatrics and Microbiology.

SELECTION CRITERIA

All randomized or quasi-randomized controlled trials where enteral antibiotics were used as prophylaxis against NEC in LBW (<2500g) and/or preterm (<37 weeks gestation) infants.

DATA COLLECTION AND ANALYSIS

The standard method of the Cochrane Collaboration and its Neonatal Review Group was used. The methodological quality of each trial was reviewed by the second author who was blinded to the trial authors and institutions. Each author extracted data separately before comparison and resolution of differences. Relative risk (RR), risk difference (RD), and number needed to treat were used in the analysis.

MAIN RESULTS

The administration of prophylactic enteral antibiotics resulted in a statistically significant reduction in NEC [RR 0.47 (0.23, 0.98); RD -0.072 (-0.136, -0.008); NNT 13.9 (7.4, 125)]. There was a reduction in NEC-related deaths which was of borderline statistical significance [RR 0.16 (0.02, 1.26); RD -0.097 (-0.183, -0.010); NNT 10.3 (5.46, 100)]. There were no significant differences in all deaths (one trial only) or in NEC-like enteropathies (one trial only). There was a statistically significant increase in the incidence of colonisation with resistant bacteria [RR 1.73 (1.00, 2. 97); RD 0.123 (0.008, 0.238); NNT 8.1 (4.2, 125)].

REVIEWER'S CONCLUSIONS

There is insufficient evidence to support the use of enteral antibiotic prophylaxis for NEC in clinical practice. To address this question further, a large trial would be required with a sample size sufficient to examine all the important benefits and harms. Adverse outcomes associated with infection, particularly with resistant bacteria, should be evaluated.