Abstract
OBJECTIVE: Studies investigating the relationship between the gut microbiome and osteoarthritis have increased in recent years. However, data on the relationship between joints and the gut microbiome are limited. The aim of this study was to determine whether there is a relation between knee joint fluid and gut microbiota in patients with knee osteoarthritis. METHODS: This study included 40 individuals, 20 of whom were diagnosed with knee osteoarthritis and 20 of whom were considered healthy controls. Joint-fluid and stool samples were taken from the participants. Bacteria isolated from the samples were identified using a matrix-assisted laser desorption ionization-time of flight-mass spectrometry device. RESULTS: Twenty-nine different bacteria were isolated from the stool samples and five bacteria were isolated from the joint-fluid samples. In our study, the same types of microorganisms (Enterococcus faecium and Staphylococcus hominis) were isolated from the stool and joint-fluid samples. CONCLUSION: The data obtained in our study shed light on the uncertainty of how microorganisms, especially those identified in the knee and hip in the literature, reach these regions. The presence of intestinal bacteria in the knee joint fluid of osteoarthritis patients indicates that intestinal bacteria, especially in individuals with a weak immune system, malnutrition, and obesity, pass through the intestinal wall and reach other parts of the body via the bloodstream, a condition also known as "leaky gut."