Lack of Bacteria May Cause Infant Colic & An Increased Risk For Disease
August 22, 2017 September 11, 2017
Lack of Bacteria May Cause Infant Colic & An Increased Risk For Disease
by Bharti Sharma, (M.P.H.)
Fig. 1: The microbial colonization of the gastrointestinal tract of infants
Baby or infant colic is also called excessive crying and has many broad definitions (Lim, 2006)10. The use of adapted Wessel’s criteria allow for a definition of baby colic as “crying spanning a time frame of over three hours in any given day without any concrete medical cause” (Savino et al, 2014)17. Some of the most recent estimates show that colic has an incidence rate of over 27% in USA (de Weerth et al, 2013)3. The prevalence rates range from 6.4 – 29% for newborn babies in the 0 to 3 months age group. Infant colic results in a lot of tension and stress for parents. In USA, one in every six parent seeks professional advice for their colicky baby (de Weerth et al, 2013; Houghteling and Walker, 2015)3, 8.
At present, physicians still continue to debate on what causes infant colic, since the pathogenesis and developmental factors are not clearly known or validated (Camilleri et al, 2016)2. Most of the previous studies done in the last decade on causes of infant colic made use of conventional culture-based techniques from samples obtained from colicky infants that were more than 6 weeks old. However, it is now known that peak time for infant colic is between the 9 to 6 week age point and abnormal gut microbiota has been implicated as a cause of infant colic (de Weerth et al, 2013; Goulet, 2015)3, 6.
At present, many theories are being explored in terms of what causes infant colic, but there is now some degree of scientific evidence that the factors responsible for the microbial colonization of the gastrointestinal tract of infants is related to the incidence of colic in the first 3 months of a newborn baby’s life (Nayak, 2014; Vallès et al, 2012; Pärtty et al, 2013)11, 18, 13. The development of the gut microbial flora is a complex interaction of various factors and as such, it is different in each baby. In current medical practice, infant colic is characterized as a condition and not as a disease. It is diagnosed by a process of symptomatic elimination by doctors (Fanaro et al, 2013)5. In most cases, due to there being marked differences in the symptoms experienced by each baby, the diagnosis of the exact cause of infant colic is difficult (Lim, 2006)10.
A new theory that is backed by evidence-based data from various studies suggests that development of infant colic is related to whether a baby was born vaginally or via a cesarean section. The theory states that the microbiomes (microorganisms or beneficial bacteria) a baby receives from its mother’s birth canal are vital for the future development of the immune system and gastro-intestinal tract microbial flora (Neu and Rushing, 2011)12. Babies born via cesarean sections don’t receive these microbiomes and this leads to the acquisition of abnormal microbial flora in the infant’s gut from environmental sources (like the walls of the operation theater). As such, these babies do not get the normal, helpful intestinal bacteria from the normal human gut. Thus, babies born through a cesarean section do have a distinct lack of the diverse bacteria found in a normal human gut. This is a possible cause for the development of infant colic as well as other problems related to problems of the immune system and central nervous system in the future (Houghteling and Walker, 2015; Nayak, 2014)8, 11. This article discusses the importance of gut microbiomes in infant colic development and possible options for treating this condition.
The Importance of Microbiomes
The microflora of the human gut has a vital role in making the intestinal environs stable. This has a great impact on the future incidence of colic, other diseases of the gut, atopy as well as food intolerance in the infant. When a baby is newly born, the gut is sterile and pioneer colonization starts following birth. The diversity of species that colonize a baby’s gut is dependent on the method used for birth. AS such, there are significant differences in the microflora of infants delivered through vaginal delivery as compare to those born via a cesarean section Nayak, 2014)11. The initial colonization of microbes in an infant’s gut lays the foundation for the lifelong adult microbiome in the future. These first few days and weeks of an infant’s life are crucial for the development of the gastro-intestinal tract’s normal microbial flora which aid in digestion as well as development of the immune system (Houghteling and Walker, 2015; Rhoads et al, 2009)8, 14.
Fig. 2: A schematic representation of potential steps of programming in the newborn infant’s gut microbiota. Key IBD- irritable bowel disease; IBS- irritable bowel syndrome; NEC-necrotizing enterocolitis; NICU- neonatal intensive care unit [Source: Goulet, O. (2015). Potential role of the intestinal microbiota in programming health and disease. Nutrition reviews, 73(suppl_1), 32-40.]
Microbiomes in Vaginal Birth Versus Cesarean Section Birth
The initial micro biotas that develop in a newborn baby’s gut are vital for the maturing process of the gut as well as the metabolic and immunologic programming of the body’s systems. Research in the last 5-7 years has demonstrated that initial bacterial colonization is involved in the incidence of future disease (this is known as microbial programming) (Koleva et al, 2015)9. The initial colonizers of infants born through vaginal birth are far more diverse and beneficial than those commonly observed in infants delivered via a cesarean section. After delivery, an infant has exposure to microorganisms originating from several sources such as the mother’s vaginal, fecal, and skin bacteria as well as the environment. The pioneer colonization of a vaginal birth newborn’s gut is totally dependent on the microbial communities present in maternal vaginal and fecal populations (Goulet, 2015)6. A vaginal birth infant gets an oral inoculation of a diverse bacterial microflora that includes facultative anaerobes like Streptococci and Enterobacteria species. Infants delivered through cesarean sections miss this initial and most significant aspect of normal microflora colonization as they fail to pass through the vaginal canal. These infants do not take in the mother’s vaginal and colon-based microbes. Following vaginal delivery, the acquired microflora continues to grow as soon as breast or oral feeding begins. Maternal breast milk has a viable microbial load of gut bacteria and also helps in further colonization of the infant’s microbiome (Houghteling and Walker, 2015)8.
Within 2 days of birth, the gut is colonized with as many as 105 colony-forming units for each ml of the gut content. In summary, the microbiomes formed in a new born baby’s gut are influenced by the mode of delivery as well as other factors like the length of gestation (was the baby born preterm or full-term), the diet (was the infant given breast milk or formula), the birthing environment of the hospital ward where the infant was kept and the level of exposure or usage of medications like antibiotics or others including proton pump inhibitors (see Fig. 2 below) (Guarino et al, 2012; Biasucci et al, 2008; Dominguez-Bello et al, 2010)1, 4.
