Neonates, especially preterm babies are susceptible to bacterial or viral infection due to their poor immune response, high sickness level, use of broad-spectrum antibiotics, presence of central lines, delayed establishment of feeding, etc. The development of the neonatal microbiome commences from the womb, where the foetus ingests and is bathed in the hypothetical ‘sterile’ amniotic fluid . Various studies have proven that neonatal oral microbiota resembles that of amniotic fluid, placenta, meconium[2,5]. Development of skin microbiome begins similarly, and varies in babies born via caesarean section or normal delivery, differences in the postnatal care, duration of intensive care stay, duration and type antibiotic therapy, KMC etc.
KMC, defined as both continuous skin-to-skin contact of the infant with the chest of the mother and exclusive breastfeeding, is among the most effective interventions for preventing death in infants with low birth weight in Low Middle-Income countries. During this process, studies7 have shown that there is a transfer of healthy microbiota from the mother replacing the pathogenic organisms. Most of the organisms belong to bacterial phyla of Actinobacteria, Proteobacteria, Bacteroidetes, Firmicutes, and Tenericutes. To our knowledge, no study to date has reported the presence of Mycobacterium species in the skin microbiome of preterm neonates whilst their intensive care stay. It was intriguing that we incidentally found these pathogenic species on preterm skin. About 83.33% & 100% of our cohort had Mycobacterium tuberculosis & Mycobacteroides abscessus respectively in the first swab which could not be explained with certainty. None of the mothers had any history of tuberculosis (any type) in the past. Family history was not available in all cases. After KMC 66.67% & 93.33% of babies had Mycobacterium tuberculosis & Mycobacteroides abscessus respectively. The relative abundance of these species decreased after KMC, however not statistically significant.
The incidence of congenital tuberculosis is about 2% in high endemic countries which is mainly by mode of vertical transmission. Postnatal transmission from caregivers to babies is also known from parents with active tuberculosis. Infants with congenital tuberculosis may be symptomatic at birth, but symptoms (mainly respiratory) can also occur within days to weeks after birth. Mortality can be as high as 40% due to respiratory failure in most cases.
In vulnerable group such as new-born population, as this study confers, is highly susceptible to multiple infectious diseases. The significance of these bacilli as part of cutaneous microbiome, during the NICU stay, post-discharge, and in the infancy period will only be known on long-term follow-up. None of the babies had any clinical signs of tuberculosis nor any mortality until discharge was attributed to tuberculosis. The mere presence of these bacilli, whether just as commensals or as potential pathogens, is alarming due to the risk of early exposure and incidence of tuberculosis right from birth.
These findings, in our view, are the first findings to be established in such a setting. Mycobacterium species detected incidentally in our study in very high percentages needs exploration with larger cohorts. Although clinically none of the mothers had any history of tuberculosis nor were active cases of tuberculosis, testing all the mothers or any surrounding source would also pose as a limitation of this study. Further larger studies are required to understand the presence of these organisms on preterm skin with long term follow up data including testing both the parents.