They are one of the cleanest environments in a hospital, but neonatal intensive care units (NICUs) still contain microbes, according to a study published in the open access journal Microbiome. The authors of this pilot study speculate that these non-pathogenic microbes then go on to populate the guts of premature babies, who do not have gut microflora due to antibiotic treatment.
When babies are delivered, their guts are normally populated with non-pathogenic microbes through the delivery process. Premature babies are administered broad spectrum antibiotics in the first week after birth to prevent infections, which removes many of these microbes. NICUs are therefore kept extremely clean to protect the premature babies, who often have weakened immune systems, from infection by pathogenic microbes.
To investigate microbes present in a NICU, researchers from the University of California, Berkeley and the University of Pittsburgh swabbed the most touched surfaces of the unit as well as collecting fecal samples from two premature babies in a small pilot study. The surfaces swabbed included the sink, feeding and breathing tubes, hands of healthcare staff and parents, access knobs on the incubator and electronic devices at the nurses' station, such as keyboard, mouse and cell phone.
The researchers then carried out a genetic analysis to identify any microbes and their abundance. They identified microbes living in the NICU with most microbes on electronic devices and sinks, and less on hands and tubes. When looking at the two infants fecal samples, to identify microbes living in their guts, they found that there was similarity with microbes identified from the NICU surfaces, with the most abundant similar to that those found on tubes.
Lead author of the study, Brandon Brooks, University of California, Berkeley, says: "The most common species found in our study (Enterococcus faecalis, Staphylococcus epidermidis, Escherichia coli, and Bacteroides fragilis) all have been associated with disease in preterm infants, but can also be commonly isolated from healthy infants and adults. The strains found here are largely opportunistic, lacking many of the really nasty genes found in 'outbreak' versions of their respective strains, and would need to be further tested to fully understand their pathogenicity in vivo. Ultimately, both infants were discharged with a healthy status."
Some of the bacteria contained resistance genes, known as efflux pumps, for pumping out the disinfectant used to clean the unit, which gives clues as to why they are present in the NICU despite being subject to regular cleaning and sterilization. The microbes in the guts of premature babies also had these resistance genes.
Brandon Brooks also said: "Hospital acquired infections are an obvious concern, and have been well studied, but the acquisition of non-pathogenic microbes from hospitals is less understood. We hypothesized that infants housed in the NICU over the first month of life are likely to acquire microbes from their immediate surroundings, however, this would need to confirmed by a larger cohort study."