New concepts in the pathogenesis of urinary tract infections

Data mining derived treatment algorithms from the electronic medical record improve theoretical empirical therapy for outpatient urinary tract infections

PURPOSE

We determined whether data mining derived algorithms from electronic databases can improve empirical antimicrobial therapy in outpatients with a urinary tract infection.

MATERIALS AND METHODS

The electronic medical records from 3,308 visits associated with a positive urine culture at Northwestern's outpatient Urology and Internal Medicine clinics and Emergency Department from 2005 to 2009 were interrogated. Bacterial species and susceptibility rates for trimethoprim-sulfamethoxazole, ciprofloxacin and nitrofurantoin were compared. Using data mining techniques we created algorithms for empirical therapy of urinary tract infections and compared the theoretical outcomes from data mining derived therapy to those from conventional therapy.

RESULTS

Patients were significantly older in the Department of Urology vs Internal Medicine vs Emergency Department, and more patients in the Department of Urology were male. During the 5-year period the susceptibility rates for ciprofloxacin in the Department of Urology and trimethoprim-sulfamethoxazole in Internal Medicine decreased significantly. In the Department of Urology the susceptibility rate for nitrofurantoin was greater than for ciprofloxacin, which was greater than for trimethoprim-sulfamethoxazole. In all departments, bacteria were more resistant to trimethoprim-sulfamethoxazole than to ciprofloxacin or nitrofurantoin. All drugs were more effective in the Emergency Department and Internal Medicine than the Department of Urology. Prior resistance patterns were the strongest predictor of current susceptibility profiles. In the Department of Urology the algorithms for patients with or without prior cultures theoretically outperformed conventional therapy in men (13.2%) and women (10.1%).

CONCLUSIONS

Antimicrobial resistance patterns in outpatient urinary tract infections are time dependent, and drug and site specific. Data mining directed therapy significantly improved theoretical outcomes compared to conventional therapy for Department of Urology outpatients and for female patients in the Emergency Department.

Prophylactic use of antimicrobials in commonly performed outpatient urologic procedures

An antimicrobial is an agent capable of killing or inhibiting the growth of a micro-organism. Antimicrobial prophylaxis encompasses efforts to prevent postprocedure infections through the use of an antimicrobial agent before, and, in some cases, for a limited time after a procedure. A thorough history and physical examination are essential to identify host factors that increase a patient's risk for postprocedural infection. Risk-modifying factors include age, anatomy, geographical area of residence, immune and nutritional status, cardiac valve integrity, prosthetic joints, the presence of indwelling hardware and distant infectious wounds. Prophylaxis for the most common urologic outpatient procedures can be attained with oral trimethoprim-sulfamethoxazole or fluoroquinolone administered between 2 h and 30 min before a procedure. Special consideration for the type and duration of prophylaxis should be given to patients with moderate to severe cardiac valvular conditions and recently inserted prosthetic joints.

Urinary tract infections in women

Urinary tract infections in female patients are exceedingly common. One third of all women with an initial UTI demonstrate recurrence, and one third of those recurrences are in the first 6 months. The potential morbidity of RUTIs is high, especially in infants, the elderly, and pregnant patients. Uropathogenic bacteria reside in the rectal vault, colonize the vagina, and then ascend per the urethra into the bladder. These bacteria avidly adhere to uroepithelial cells using pili and can further ascend to the kidneys. Empiric treatment of an initial uncomplicated UTI is acceptable, but recurrences warrant a urine culture and possible radiographic evaluation. Fluoroquinolones are now first-line medications for UTIs, except in geographic areas where resistance to TMP-SMX is still low. Response to therapy should govern the need for additional treatment. Certain motivated patients with three or more UTIs per year should be considered for prophylaxis therapy.