Culturable gut bacteria lack Escherichia coli in children with phenylketonuria

Phenylketonuria (PKU) is an inherited metabolic disorder that affects phenylalanine metabolism. If left untreated, phenylalanine builds up to harmful levels in the body and may cause intellectual disability and other serious health problems. The aim of this study was to compare the culturable predominant bacteria in the gut of PKU versus non-PKU children in Jordan to measure the effect of a PKU low-protein diet on the normal flora. Escherichia coli is a bacterium of the normal gut flora in humans and vitally benefits the hosts in producing vitamin B(2) (riboflavin) and vitamin K(2) (menaquinone) involved in human cellular and bone metabolism, respectively. For a small-scale observational study, stool samples were collected from 25 children divided into 20 subjects without PKU as controls and five PKU subjects. Only predominant culturable bacteria were isolated from the stool on CLED (cysteine–lactose–electrolyte-deficient) agar, which was a limitation of this study. Samples were incubated at 35 ± 2°C, observed after 24–48 h, and transported to an automated microbial analyser. Data analysis was obtained using the independent sample t-test to determine any statistically significant difference in the microbial gut community between the associated population means. It was statistically significant (p < 0.01) that E. coli was present in all control subjects, while it was absent from the gut flora of all PKU subjects. Additional studies on a larger scale are needed to confirm these results and also any association with blood serum levels of phenylalanine and vitamins B(2) and K(2).