You Still Need the Data

A recent study (J Pediatr 2014; 165: 23-9) confirmed the obvious: “early empiric antibiotic use in preterm infants is associated with lower bacterial diversity.”  That being said, you still need the data and the specific changes are of importance.

This study examined the stools from 74 preterm infants (≤32 weeks gestational age) and determined how the microbiota changed in relation to no antibiotics (18% of cohort), brief antibiotics (1-4 days) (64% of cohort), or ‘intensive’ antibiotics (5-7 days) (18% of cohort).  Empiric antibiotics consisted of ampicillin and gentamicin.  Stools were analyzed with the 16s ribosomal DNA community profiling.

The key findings are graphically shown in Figure 1 with pie charts showing the relative abundance of 10 bacterial genera at week 1, week 2, and week 3 in each of the three groups.

  • Those who received 5-7 days of antibiotics had the most changes in their microbiota with increased Enterobacter and lower bacterial diversity in the second and third weeks of life.
  • In those who received no empiric antibiotics there was increasing bacterial diversity noted sequentially.  These changes were not seen in either of the antibiotic groups. However, the group with brief antibiotic exposure returned to their baseline diversity by week 3.
  • Infants receiving early antibiotics experienced more cases of necrotizing enterocolitis, sepsis and death than those who were not exposed to antibiotics (this was not proven to be casually-related).

Take-home message: This study proves that antibiotics change the microbiome in neonates and that neonates exposed to antibiotics may have complications as a result.  Better biomarkers (with rapid turn around time) would allow more careful selection of which neonates need empiric antibiotics.

Related blog posts:

Looking Beyond the Headline for Ultra-Short Bowel Syndrome

A quick glance at a recent study (JPGN 2014; 58: 438-42) suggests a favorable outlook for patients with ultra-short bowel syndrome (U-SBS). U-SBS has been defined as having a residual small bowel length <10 cm distal to the ligament of Treitz.  A more cynical definition by a colleague years ago was that U-SBS was when patients can fart and burp at the same time.

Looking at the details:  This study enrolled 11 patients into a prospective Italian database since 2000 and examined their outcomes.  Inclusion criteria included U-SBS diagnosed in the neonatal period (<28 days) and necessitating home parenteral nutrition at discharge.

The demographics note that these patients were bigger at birth and less premature than typical series of patients with SBS:

  • Only one of the patients had necrotizing enterocolitis as the sole underlying disease and six patients had volvulus.
  • All but two had ≥50% of their colons, with five having their entire colon.
  • All but one of these patients had gestational age ≥32 weeks and only two  patients had documented birth weight less than 2300 gm.

The authors note that these patients currently receive SMOFlipid as outpatients and Omegaven as inpatients.  All patients receive some enteral feedings.  Loperamide is used selectively.

Results:

  • Inpatient hospital care ranged from 23 to 104 days/year, but had improved during the last year of followup.
  • With >5 years of followup, 2 of the 11 patients had died.  One of these patients had severe intestinal failure associated liver disease (IFALD) despite use of Omegaven.
  • One patient underwent isolated intestinal transplantation.
  • No children in this series underwent a bowel-lengthening…”given the shortness of the residual small bowel, the gain of length after any procedure will not significantly improve absorption.”

Given their results, the authors note that despite recommendations for early referral for intestinal transplantation in patients with U-SBS, this may not result in a survival benefit.  They note a study by Pironi et al (Gut 2011; 60: 17-25) that showed that among 80 intestinal transplant candidates, 5-year survival was greater in those who were not transplanted.

Bottomline: This small cohort shows that certain populations of U-SBS may do well clinically for a long time with medical management. Caution should be used in extrapolating these results to SBS patients with different demographics.

Therapeutic Inertia in U.S Neonatal Units (vis-a-vis Probiotics)

“More than 90% of very low birth weight (VLBW) infants receive substandard care” could be the headline of a recent article/editorial (J Pediatr 2014; 164: 980-5 & 959-60).  Instead they are titled: “Cohort Study of Probiotics in a North American Neonatal Intensive Care Unit” and “Probiotic Supplementation in Preterm Infants: It is Time to Change Practice.”

In the article introduction, the authors state: “In 2011, faced with overwhelming evidence that probiotics could decrease NEC in preterm infants, and because there were no significant risks described in the extensive literature, we decided to introduce probiotics as routine care for the prevention of NEC.”

Methods: Prospective cohort study of infants at a single center NICU.  Examined rates of necrotizing enterocolitis (NEC) and death for 17 months before and after introduction of a probiotic (FloraBABY).  This probiotic (0.5 g) was mixed with water and administered just before milk once a day.  It was started at the first feeding and continued until the infant reached 34 weeks postmenstrual age.

Key findings:

  • Probiotics reduced NEC from 9.8% to 5.4% (OR for NEC 0.51)
  • Probiotics reduced combined outcome for NEC or death from 17% to 10.5% (OR 0.56).  Reduction in death by itself did not meet statistical significance.

Why, in 2012, were probiotics only used in 8-9% of VLBW?

Potential profits for probiotics are small which has limited studies of specific strains.  The probiotic, FloraBABY, in this study cost 11 cents per day in amount used; however, since the probiotic came in a tub, the actual cost was $12.79 for a 60-g tub for each patient.  Thus, manufacturers are unlikely to support studies to garner FDA approval.

Yet, there have been 22 randomized controlled trials published which “showed substantial benefits of probiotics and no adverse events.” A recently completed ProPrems trial (Jacob S et al, presented at 2013 PAS Annual Meeting) used a probiotic called ABC Dophilus Probiotic Powder for Infants.  This trial showed “a significant, >50%, reduction in NEC despite an incidence in their control patients of only 4.4%” and despite the fact that >95% of infants received breast milk.

“Good quality control and confirmation of the contents of the preparation are essential…There seems to be no further reason to delay the introduction of this evidence-based therapy in the NICU.”  The adoption of probiotics could avoid 2500 cases of NEC every year in North America.

The editorial notes that the evidence for probiotics is much better than many other therapies used in NICUs.  They note that some have argued that “the evidence that probiotics reduce mortality rates is as conclusive as that for surfactant for respiratory distress syndrome.”  A recent Cochrane review of 17 trials and >4900 VLBW infants showed that the RR of severe NEC for probiotics versus control was 0.41.

If people really understood this issue, there would be outrage over this issue.  In the U.S., there was recently extensive coverage over inaction about a faulty ignition switch which has been linked to at least 13 deaths.  The potential reduction in NEC and deaths with probiotics is likely much greater.

While the editorial recommends involving parent representative groups, I recommend discussing this issue with your neonatology colleagues along with your “quality care” team to find out what they are going to do about it.  Given the enormous costs in most NICUs, it is likely that each unit could self-fund a quality project (with consented patients) to provide probiotics to this vulnerable population.

Bottomline: Probiotics have excellent evidence as prophylaxis for NEC in VLBW infants.  Physicians need to advocate for their usage to “avoid years of therapeutic inertia.”

Related blog post: One More Day Syndrome & Necrotizing Enterocolitis …

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

The Genius of Breastmilk

While there has been a lot of talk about how breastmilk improves IQ/development (see links below), there are many other reasons why breastmilk is amazing.  For example, breastmilk reduces the risk of necrotizing enterocolitis (NEC).  A recent study on this effect: J Pediatr 2013; 163: 1592-5.

In this multicenter randomized controlled trial involving 7 NICUs, the authors studied extremely premature infants whose mothers did not provide their breastmilk.  Infants were fed either a cows-milk based preterm formula (COW, n=24) or pasteurized donor human milk (HUM, n=29). Birth weight and gestational age were similar in both groups, approximately 990 g and 27.5 weeks respectively.

Results:

  • HUM patients had fewer days of parenteral nutrition: 27 vs. 36, P=.04
  • HUM patients had fewer bouts of NEC: 1 (3%) vs. 5 (21%), P=.08; surgical NEC occurred 4 times in COW group compared with 0 in HUM patients (P=.04)

Take-home message: The data from this study are in line with recent American Academy of Pediatrics policy statement that recommends the following: “premature infants should receive only human milk from their mother and that, if it is not available, pasteurized donor human milk should be used.”

Another relevant study: J Pediatr 2010; 156: 562-7.

Related blog posts:

Rehabilitation for Short Bowel Syndrome

As noted in several blog posts, there have been some important advances in the care of short bowel syndrome (SBS)/intestinal failure (IF) patients which have resulted in improved outcomes.  A recent review of 28 children with ≤20 cm of small bowel has been published (J Pediatr 2013; 163: 1361-6, editorial 1243) and provides tangible evidence of these changes.

This retrospective study reviewed the charts of these children managed at Omaha’s intestinal rehabilitation program.  7 patients had NEC, 6 intestinal atresia, 6 had gastroschisis, 3 omphalocele, 5 had malrotation, and 1 patient had vascular disease.

Key results:

  • 27 survived (96%)
  • 14 (50%) had at least one lengthening procedure; in this cohort, bowel lengthening was not associated with a greater rate of adaptation than native bowel.
  • 13/27 (48%) achieved parenteral nutrition independence (“nutritional autonomy”) with their native bowel.
  • Predictors of “successfully rehabilitated” patients: intact colon and ileocecal valve
  • All patients had improvements in lowering PN requirements, total bilirubin, and growth z-scores.
  • Serum transaminase levels did not improve in the nonrehabilitated patients

The main medical treatments at IRP include use of agents for control of bacterial overgrowth, reducing gastric acid production, lipid minimization, promotility and antimotility agents (eg. loperamide), and ethanol locks.  The editorial comments on the “poor results” for surgical intervention, “particularly among those with ultra-short bowel.” This may be due to ‘marginal motility, ischemia, severe wall thickening, or due to adhesions.’

With regard to ethanol locks, the editorial supports them but states, “the main factor in prevention [of line infections] has been maintaining a consistent and strict protocol for catheter care.”

Previous related blog entries:

One More Day Syndrome & Necrotizing Enterocolitis

In many situations, the advice is to wait one more day and then decide/act; however, sometimes one more day winds up being a week, a month, or longer.  A recent editorial indicates that there is enough evidence now for probiotic usage in neonates to prevent necrotizing enterocolitis (NEC).  The authors state that to continue “with the standard of care, in which no new products are provided…is ethically unacceptable” (JAMA Pediatrics 2013; 167: 885-6).  Thanks to Ben Gold for this reference.

Key arguments:

  • A 2011 Cochrane review identified 16 eligible trials with 2842 premature infants (<2500 g, <37 weeks).  Probiotics reduced the incidence of NEC with a relative risk of 0.35 and mortality with a relative risk of 0.40.  Despite the typically cautious recommendations from Cochrane reviews, the authors state “updated review of available evidence supports a change in practice.”
  • While the American Academy of Pediatrics in 2010 noted there is some evidence to support probiotic usage and called for more studies, there are no studies currently being conducted in the U.S.
  • The authors note that the “FDA Center for Biologic Evaluation and Research is committed to policies that effectively prohibit probiotic efficacy trials.” Under current policies, the authors state these “studies will not be conducted in a US setting for the next 20 to 30 years.”
  • Other countries , like Australia, allow use of probiotic with parental consent.
  • The authors propose that probiotic efficacy be studied in a comparative effectiveness design.

Bottomline: Current regulations have stymied the use of probiotic trials for NEC.  What will it take for regulatory agencies to relent and allow this promising research?

Related blog posts:

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) and specific medical management interventions should be confirmed by prescribing physician.  Application of the information in a particular situation remains the professional responsibility of the practitioner.

How Histamine-2 Receptor Blockers May Cause Problems for Preemies

Previously, this blog has noted an association between ranitidine usage and necrotizing enterocolitis (NEC) (see below).  Now, another study provides insight into a potential mechanism (JPGN 2013; 56: 397-400).

This study examined the fecal microbiota in 76 premature infants who were enrolled in a case-controlled, cross-sectional study.  25 infants receiving H2-blockers were compared with 51 matched controls.

Results: microbial diversity was lower, relative abundance of Proteobacteria was increased, and Firmicutes was decreased in the stools of infants receiving H2-blockers.

While this study did not specifically examine the effect of H-2 blockers on NEC (no infants in this study had NEC), there are multiple reasons why the findings should be a cause for concern.

  • Gastric acidity acts as a natural defense against bacterial growth and H-2 blockers (as well as proton pump inhibitors) inhibit this defense
  • Previous studies have shown an association between NEC and with diminished microbial diversity/increased Proteobacteria.  Proteobacteria include well-known pathogens like Klebsiella, Shigella, Escherichia coli, and Citrobacter.

Related blog entries:

Green beans for short gut syndrome

A recent article indicates that the addition of green beans may improve diarrhea and reduce dependence on parenteral nutrition (Adding Dietary Green Beans to Formula Resolves the Diarrhea ) (ICAN. DOI: 10.1177/1941406412469403). Thanks to Kipp Ellsworth for pointing out this reference on his twitter feed.

This small retrospective study of 18 infants examined the addition of green beans to the diet of infants with short bowel syndrome (SBS) (1 jar of stage 2 baby food green beans to every 8 ounces of 30 cal formula).  The average gestational age of the patients was 32 weeks (range 23-39 weeks) and the average birth weight was 1938 gram.  Nine patients had NEC, four had gastroschisis, two had Christmas tree defect, and three had other reasons for either SBS or intestinal failure.  The IF group (n=10) was defined as being dependent on parenteral nutrition to meet nutritional needs; the SBS group (n=8), who were more severely affected, was defined as the malabsorptive state that follows a massive resection.

Products that were used:

  • Gerber Natural Select: 3 gm of fiber per 4 ounce
  • Beach-Nut Homestyle: 2 gm of fiber per 4 ounce
  • HyVee Mother Choice: 2 gm of fiber per 4 ounce
  • These products average 32% soluble and 68% insoluble fiber

While the authors note that they use only amino-acid based formulas currently, at the time of the study, 61% were receiving Peptamen Junior.

It is not clear in the manuscript exactly at what age green beans are introduced. However, a previous case study suggested addition of green beans at ~4 months or >44 weeks postconception.  This prior case study indicated that adding stage 2 green beans changed the caloric density of 30 cal formula to 22 cal/ounce (Nutrition in Clinical Practice 2005; 20: 674-77).  In addition, this adds 2 gm/kg/day of fiber.

Results from current study:

  • 9 of 10 IF patients were able to discontinue parenteral nutrition
  • 2 of 8 SBS patients were able to discontinue parenteral nutrition
  • All infants had improvements in stool consistency, typically within 24 hours of dietary change.

While the authors acknowledge the limitations of the study, they hypothesize that the reason for improvement is due to the fiber content of green beans.   Fermentation of dietary fiber produces short chain fatty acids (SCFAs) which in turn have a trophic effect on the mucosa and enhance nutrient absorption.

Studies have shown that adults with IF or SBS have improved stool consistency with the addition of fiber.  However, the authors note that there have been no studies documenting the effectiveness of dietary fiber in the pediatric SBS/IF population.

Whether green beans would outperform other sources of fiber like pectin, guar gum, bananas or benefiber is not clear.

Additional references/links:

Predicting Necrotizing Enterocolitis with Fecal Biomarker

A recent study has shown some promise in detecting necrotizing enterocolitis (NEC) with a fecal biomarker, S100A12 (J Pediatr 2012; 161: 1059-64).

In this prospective study of 145 preterm infants with a birth weight <1500 g, stool samples were collected on alternated days for 4 weeks.  Fecal S100A12 and calprotectin were measured.  Calprotectin in previous studies has been shown to be a poor marker for NEC.

Fecal S100A12, also called calgranulin C, belongs to a novel group of proinflammatory molecules. It is released by activated or damaged cells under conditions of cell stress and indicates phagocyte-specific damage.

18 (12.4%) developed NEC.  Fecal S100A12 levels were elevated in severe NEC and also at 4-10 days beforehand.  The sensitivity, specificity, positive predictive values, and negative predictive values were 70%, 68%. 37%, and 89% respectively.  Thus, there is limited utility of this stool test due to the limited sensitivity/specificity.  There is substantial overlap between control patients and patients who developed NEC.  Furthermore, fecal S100A12 levels are age-dependent.  Generally, they are higher early in life, likely due to increased mucosal permeability.

Calprotectin levels were elevated at the onset of NEC (median 349 mg/kg) and 48 hours before onset (median 83 mg/kg).  The difference at 48 hours prior to onset did not reach statistical significance.