So, what’s left?
This is, after all, considered a very simple procedure, and one that is often taught as a first procedure in the neonatal intensive care unit, as well as being taught to parents for care of their infant at home.
However, evidence shows that there may be other issues that we need to consider in the care of a feeding tube. One of these issues is the presence of bacteria in the tube.
Feeding tube bacterial colonization
Several studies have shown that a bacterial biofilm forms fairly quickly in the feeding tube.1, 2,3 This biofilm serves to “protect” the bacteria from being easily cleansed away or killed, but could result in the biofilm with encapsulated bacteria being released in the gastrointestinal tract and causing feeding intolerance or sepsis. The presence of bacteria in the gut is normal and, in fact, protective.
There are a few published studies that have looked specifically at colonization of feeding tubes, one of which also looked at blood stream infections related to the specific organism cultured from the feeding tube and another at feeding intolerance1,2. These studies evaluated bacteria found in the feeding tube based on the feeding solution and dwell time of the tube.
The first study’s intent was to identify any association with feeding regimen, i.e. formula vs breast milk.1 They found colonization occurred in all feeding tubes, even those from babies who were not fed through the tube. The organisms were different but still present. Two of the organisms caused infections in the patients. These two organisms accounted for 51% of all organisms and were Klebsiella and Serratia.
The second study cultured tubes after seven days and found all but one tube was colonized with various organisms, including Klebsiella.2 They observed feeding intolerance in 24 out of 32 contaminated tubes, but none in the tubes that were not contaminated.
Gomez et al studied bacterial growth at the connector between the feeding tube and extension tube. They found a thick bacterial biofilm had formed in as little as 24 hours.3 They compared bacteria in the feeding tube connector with bacteria in the infant’s stool to see if it could be determined if bacteria was coming from the feeding, or if there was retrograde growth from colonization in the infant’s gastrointestinal tract as was shown in an adult study.4 Gomez et al found that about half of the cases showed presence of bacteria in the feeding tube days before it was present in the feces and half showed the opposite with specific bacteria found in the feces before being found in the feeding tube.3 This demonstrated that the bacteria were being transferred in both directions! Furthermore, a recent publication of data from the Hurrell study evaluated the E. coli strains found in the tubes from that study. They concluded that the E. coli was likely from environmental sources and not from the infant.5 They also found some strains that were antibiotic resistant, raising further concerns about the effect on infant health.
It is now believed that the preterm infant’s intestines are colonized before birth, contrary to what we used to think about this colonization happening entirely after birth 6,7,8. It also turns out that the mother’s own microbiome, and other factors, influence this initial colonization.
Colonization of the neonatal gut is influenced by mode of delivery and important for many reasons, including immune development and avoidance of bacterial overgrowth. The colonization of Bacteroides is earlier and with higher levels in infants born vaginally versus those born via cesarean section.9 Cesarean section has also been shown to result in lower colonization with Lactobacillus and Bifidobacterium. These beneficial bacteria are referred to as commensal bacteria and bacteria that commonly lead to disease are referred to as pathogenic bacteria.
Important to the microbiome are both the number and diversity of bacteria. While beneficial in the gut, they may cause infection if outside the gut. Chronic stress and pain such as that experienced by some NICU patients can lead to translocation of bacteria from the gut into the bloodstream, leading to infection.10 At least three studies have published the effect of antibiotic exposure on the risk of necrotizing enterocolitis, death or late onset sepsis. In all cases, the risk of all of these increased with additional exposure to antibiotics.11,12,13
This information should raise concern for all clinicians, and perhaps indicate a need for changes in clinical practice. I’ll discuss those issues more in depth in next month’s blog post.
Did you miss part 2 of Sandy’s Neonatal Gastric Tube blog series? Read it here!
- Hurrell, E., Kucerova, E., Loughlin, M., Caubilla-Barron, J., Hilton, A., Armstrong, R., … & Forsythe, S. (2009). Neonatal enteral feeding tubes as loci for colonisation by members of the Enterobacteriaceae. BMC infectious diseases, 9(1), 146.
- Mehall, J. R., Kite, C. A., Saltzman, D. A., Wallett, T., Jackson, R. J., & Smith, S. D. (2002). Prospective study of the incidence and complications of bacterial contamination of enteral feeding in neonates. Journal of pediatric surgery, 37(8), 1177-1182.
- Gómez, M., Moles, L., Melgar, A., Ureta, N., Bustos, G., Fernández, L., … & Jiménez, E. (2016). Early Gut Colonization of Preterm Infants: Effect of Enteral Feeding Tubes. Journal of pediatric gastroenterology and nutrition, 62(6), 893-900.
- Mathus-Vliegen EMH, Brediu MWJ, Binnekade JM. Analysis of sites of bacterial contamination in an enteral feeding system. Journal of Parenteral and Enteral Nutrition. 2006;30(6):519-525.
- Alkeskas, A., Ogrodzki, P., Saad, M., Masood, N., Rhoma, N. R., Moore, K., … & Forsythe, S. (2015). The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes. BMC infectious diseases, 15(1), 449.
- Gregory, K.E. (2015). Guest Editorial: Unraveling the Microbiome. Advances in Neonatal Care, 15(5),312-313.
- La Rosa, P. S., Warner, B. B., Zhou, Y., Weinstock, G. M., Sodergren, E., Hall-Moore, C. M., … & Hoffmann, J. A. (2014). Patterned progression of bacterial populations in the premature infant gut. Proceedings of the National Academy of Sciences, 111(34), 12522-12527.
- Koenig, J. E., Spor, A., Scalfone, N., Fricker, A. D., Stombaugh, J., Knight, R., … & Ley, R. E. (2011). Succession of microbial consortia in the developing infant gut microbiome. Proceedings of the National Academy of Sciences, 108(Supplement 1), 4578-4585.
- Dunlop, A. L., Mulle, J. G., Ferranti, E. P., Edwards, S., Dunn, A. B., & Corwin, E. J. (2015). The Maternal Microbiome and Pregnancy Outcomes that Impact Infant Health: A Review. Advances in neonatal care: official journal of the National Association of Neonatal Nurses, 15(6), 377.
- Cryan, J. F., & Dinan, T. G. (2012). Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nature reviews neuroscience, 13(10), 701-712.
- Alexander DF. Why should there be an NICHD? 2011;127(2):325-333
- Kuppala, V. S., Meinzen-Derr, J., Morrow, A. L., & Schibler, K. R. (2011). Prolonged initial empirical antibiotic treatment is associated with adverse outcomes in premature infants. The Journal of pediatrics, 159(5), 720-725.
- Cotten, C. M., Taylor, S., Stoll, B., Goldberg, R. N., Hansen, N. I., Sánchez, P. J., … & Benjamin, D. K. (2009). Prolonged duration of initial empirical antibiotic treatment is associated with increased rates of necrotizing enterocolitis and death for extremely low birth weight infants. Pediatrics, 123(1), 58-66.