Kawasaki disease occurs in young children, and is characterized by long-lasting fever, coughing, diarrhea, along with other symptoms. What specifically causes this disease is unknown, but scientists guess it may be influenced genetically or by intestinal microbiota. Japan seems to have an unusually high rate of occurrence of KD. Researchers in Tokyo performed a longitudinal study of the intestinal microbiomes of KD patients, in order to look for any patterns that could suggest a relationship between intestinal microbiota and Kawasaki disease. The results have been published by Frontiers in Microbiology.
Fecal samples were collected from 28 Japanese children, ages ranging from 3 months to 9 years 6 months. Patients were both male (15) and female (13). Fecal samples were collected twice from each child, for a total of 56 samples. The first (acute phase) sample was taken at the time of hospital admission, while the second (non-acute phase) was collected 4-6 months after the onset of Kawasaki disease. DNA was extracted from the fecal samples and sequenced to determine the bacterial composition of the intestines.
Roseburia species were found to be relatively abundant during the non-acute phase (4-6 months after disease onset). Species of Streptococcus were found mainly during the acute phase, such as S. pneumonia, orlais, pseudopneumoniae, mitis, gordonii, and sanguinis. This means there is a potential that these species of Streptococcus could be related to KD. To further determine if the Streptococcus species were related to KD, the researchers compared the species’ genomes to recent research in which they are involved, and found that Streptococcus could be a biomarker or pathogen for diseases with unknown causes, such as Kawasaki disease. While this is still a hypothesis and nothing is proven to be 100% true yet, it is definitely a topic that will be researched extensively in the nearby future. It may hold the key for understanding many other diseases whose causes are a mystery.