140 страниц. 2012 год. LAP Lambert Academic Publishing For the critical role of DNA in pathogenesis and the absence of in vivo study tracing the comparison between prokaryotic unmethylated DNA and eukaryotic slightly methylated DNA in the respect of the urinary system this study aimed for the followings: Isolation and identification of S. aureus and C. albicans from urine clinical sources. Determination the susceptibility of S. aureus to commonly used antibiotics and screening of the most sensitive S. aureus isolate. Extraction and purification of DNA from the chosen isolates and determination of its concentration and purity by measuring absorbance by a UV spectrophotometer. Comparative histopathological study of the whole bacterial S. aureus, yeast C. albicans cells, and different concentrations of DNA extracted from S. aureus and C. albicans in mice models of urinary tract infection.