Management

Selection of antibiotics should rely primarily on urine culture and sensitivity (CandS) results, which are based on agar disk-diffusion or the minimum inhibitory concentration (MIC) method.

Renally excreted drugs and those being concentrated in the urine should be selected to manage chronic UTI, however, additional considerations include route and frequency of administration, adverse effects, cost, and the target organ (e.g. kidney, bladder, prostate). Ideally, antibiotic agents with high suscepti­bility should be used. The use of drugs with intermediate susceptibility might be appro­priate when the other options are associated with a high prevalence of side-effects, are not easy to administer, should be reserved and used only as a last resort, or are cost prohibi­tive. In these scenarios, and when clinical signs are not life threatening, drugs with intermediate susceptibility can first be admin­istered. In some instances, especially when more than one pathogen is involved, combi­nation therapy might be indicated.

When UTI is recurrent it should not be regarded as an “antibiotic responsive disorder”; instead, predisposing factors should be sought and eliminated in addition to antibiotic therapy. Predisposing factors include anatomical abnormalities (e.g., ectopic ureters, abnormal vulvar conforma­tion, urachal diverticulum), functional abnor­malities (e.g., chronic kidney disease), metabolic disorders (e.g., diabetes mellitus, hyperadrenocorticism), neoplasia, urolithia­sis, and causes for incomplete urinary bladder emptying. The diagnostic workup should be tailored for the individual patient.

Treatment of complicated or recurrent UTI should always be guided by culture and sensi­tivity testing due to relatively long treatment durations and the potential use of second- and third-line antibiotics. Misuse of antibiotics will promote resistance and when not based on culture and sensitivity results may also be ineffective. Whenever possible, the use of highly potent drugs (e.g., vancomycin, car- bapenems) should be avoided and used only in rare instances of life-threatening or highly resistant infection. Treatment duration is determined by the nature of the infection and the organs involved. Evidence to support the treatment duration for complicated UTI is lacking, but administration of antimicrobials for a period of approximately 4 weeks is com­mon practice. When pyelonephritis is sus­pected, treatment is indicated for an even longer period.