Abstract

ABSTRACT: BACKGROUND: The reticuloendothelial system (RES) play an important role in immunity against bacterial infection and Klebsiella pneumoniae one of the most common causes of hospital-acquired infections. Dextran70 (D70), a polysaccharide, may alter functions of this system through changing many biological activities in the tissues. OBJECTIVE: This study focuses on the prophylactic effects of D70 on RES in systemically challenged mice with K. pneumoniae which has been isolated from urine sample of patient with urinary tract infection. METHODS: Four groups of adult white mice were intravenously injected with K.pneumoniae. Three groups of them was preinjected intraperitonealy for three successive days with 0.5 , 1, and 2 mg D70/100 g body weight, and the fourth group was challenged only as a control group. The ratio of liver and spleen weights to body weight was calculated and histological sections for heart, lung, and kidney were examined after 24 and 48 hours from challenge in all groups. RESULT: The results revealed that an increasing in the ratio of liver weights to body weight in control group, while there is slight increase in the three groups treated with D70. The ratio of spleen weights to body weight was more increasing after 24 hours in both 0.5 and 2 mg D70/100 g body weight of treated groups. The histological study demonstrated suppurative lesions and abscesses in the heart, lung, and kidney due to K. pneumoniae infection in the control group, while pretreated mice with D70 have clearly demonstrated less pathological changes and more integrity of the tissues comparative to control group