Effect of gamma radiation therapy on microorganisms causing secondary infection in patients with cancer bladder

ABSTRACT

Urinary tract infection in cancer patients is of major importance not only because it is of common occurrence but also because it may be the source of blood invasion by bacteria or their products. In this study, 130 midstream urine samples collected from patients with cancer bladder were cultured on different media. All isolated bacteria and yeast were identified systematically and than subjected to these investigations Sensitivity to increasing doses of gamma radiation, sensitivity to different antimicrobial agents and measurement of DNA content by cytophotometry. Bacteria and yeast were isolated from urine in 73 cases [56.15%] of all cases [130]. E. coli was isolated in 31.4%, Pseudomonas aeroginosa in 21.9%, Proteus in 12.3%, Staph. aureus in 18.2% and Candida in 4.1%. Pseudomonas was the most sensitive organism to gamma radiation D10 [0.06 KGy] followed by E. coli D10 [0.35 KGy] then Staph. D10 [0.36 KGy] while Candida was the most radio resistant D10 [1.11 KGy]. All tested organisms had higher DNA content after exposure to therapeutic dose of radiation than before radiation. These changes in DNA content lead to changes in the sensitivity of organism to different antibiotics, sublethal doses of radiation cause an increase in spontaneous emergency of resistant mutants. Changes in DNA content and antibiotic sensitivity were statistically significant