Mouse Model of Ascending UTI Involving Short- and Long-term Indwelling Catheters

Publisher Summary This chapter presents mouse models of ascending urinary tract infections (UTI) involving short- and long-term indwelling catheters. This model uses the mouse CBA/J inbred (F200) substrain originating in a cross of a Bagg albino female and a DBA male. Female mice 6–8 weeks of age, 20–22 g, are used. Prior to experimental use, a urine sample is obtained for culture to assure the absence of bacteriuria. During handling of animals, spontaneously voided urine can be obtained. In case of short-term indwelling catheter model, the mice are anesthetized with either methoxyflurane inhalation using an open-drop nose cone or with 50 mg/kg pentobarbital intraperitoneally. A scavenging fume hood is used while anesthetizing mice with methoxyflurane. Animals respond to anesthetic within five minutes and remain anesthetized for 20–30 minutes. The anesthetized mouse is placed in a supine position and the periurethral area is swabbed with povidone iodine solution, which is rinsed off with sterile water. The 25-mm-long catheter is advanced along the stylet to push the 4-mm-long segments off the stylet and into the bladder. In the long-term model, a single 4-mm-long catheter is secured by a single suture within the bladder lumen. While the mice are still anesthetized, the mouse abdomen is disinfected with povidone iodine and alcohol scrub and the bladder is exposed by a midline abdominal incision. The UTI is then documented by using quantitative cultures of bladder and kidney homogenates and light-microscopic examination of sections of bladder and kidney to assess histologic changes. The models are useful in assessing the effect of an indwelling bladder catheter on microorganism uropathogenicity; efficacy of antimicrobial therapy; attachment patterns of uropathogens to uroepithelial cells; and host response to infection including changes in antibacterial leukocyte function, host inflammatory response, and specific antibody responses.