Urinary tract infections

Most urinary tract infections (UTIs) are caused by facultative anaerobes originating from the bowel reservoir. Escherichia coli is responsible for over 85% of community-acquired UTIs while other enteric gram-negative bacteria such as Proteus and Klebsiella species are far less common. Community-acquired enteric gram-negative bacilli have developed increasing resistance to ampicillin and even trimethoprimsulfamethoxazole, but remain susceptible to most first-generation cephalosporins, quinolones, and amino-glycosides. A different distribution of uropathogens is found in hospitalized patients; Escherichia coli accounts for only about 30 to 50% of infections while Klebsiella, Serratia, Pseudomonas aeruginosa, Enterobacter, Citrobacter, Proteus, enterococci and staphylococci are isolated more frequently. Corynebacterium group D2, recently recognized as a nosocomial uropathogen, is highly resistant to most antimicrobials with the exception of vancomycin [1]. Anaerobic organisms are rarely involved in UTIs and fungal infections generally occur in catheterized patients.