Two Simple Rules for Improving the Accuracy of Empiric Treatment of Multidrug-Resistant Urinary Tract Infections

Abstract

The emergence of multidrug-resistant (MDR) uropathogens is making the treatment of urinary tract infections (UTIs) more challenging. We sought to evaluate the accuracy of empiric therapy for MDR UTIs and the utility of prior culture data in improving the accuracy of the therapy chosen. The electronic health records from three U.S. Department of Veterans Affairs facilities were retrospectively reviewed for the treatments used for MDR UTIs over 4 years. An MDR UTI was defined as an infection caused by a uropathogen resistant to three or more classes of drugs and identified by a clinician to require therapy. Previous data on culture results, antimicrobial use, and outcomes were captured from records from inpatient and outpatient settings. Among 126 patient episodes of MDR UTIs, the choices of empiric therapy against the index pathogen were accurate in 66 (52%) episodes. For the 95 patient episodes for which prior microbiologic data were available, when empiric therapy was concordant with the prior microbiologic data, the rate of accuracy of the treatment against the uropathogen improved from 32% to 76% (odds ratio, 6.9; 95% confidence interval, 2.7 to 17.1; P < 0.001). Genitourinary tract (GU)-directed agents (nitrofurantoin or sulfa agents) were equally as likely as broad-spectrum agents to be accurate (P ‫؍‬ 0.3). Choosing an agent concordant with previous microbiologic data significantly increased the chance of accuracy of therapy for MDR UTIs, even if the previous uropathogen was a different species. Also, GU-directed or broad-spectrum therapy choices were equally likely to be accurate. The accuracy of empiric therapy could be improved by the use of these simple rules.T he incidence of infections caused by multidrug-resistant (MDR) Gram-negative bacterial uropathogens is increasing among both hospitalized patients and patients in the community (1, 2). The emergence of these pathogens creates challenges for physicians when choosing empiric treatment, as therapeutic options are often limited. Current guidelines for the treatment of urinary tract infections (UTIs) from the Infectious Diseases Society of America (IDSA) recommend that antimicrobial resistance rates be considered and that patient risk factors be taken into account (3). However, with rates of extended-spectrum beta-lactamase (ESBL) production among uropathogens approaching 10% (4, 5), additional strategies for selecting an accurate antimicrobial agent are needed.Studies suggest that empiric treatment for patients with bacteremia caused by ESBL-producing strains accurately covers the pathogen in only half of all cases (6, 7). Inaccurate therapy has been associated with both increased morbidity and increased mortality (6-8). In addition, use of inaccurate therapy for MDR UTIs can increase both the cost of care and the length of stay for hospitalized patients (9). As urinary sources are one of the most common sources of bacteremia caused by Gram-negative bacteria and treatment for UTIs is usually initiated prior to the availability of microbiologic data,...

Urinary Tract Infection and Asymptomatic Bacteriuria in Older Adults

“…When choosing empiric treatment in these settings, the provider should refer to the results of prior urine cultures if any are available. A study done in predominantly older men with UTI caused by MDRO found that prior urine culture results, even those collected as long ago as two years from the index case, were useful at predicting the causative pathogen and its susceptibilities [70]. …”

Clinical Management of an Increasing Threat: Outpatient Urinary Tract Infections Due to Multidrug-Resistant Uropathogens: Table 1.

“…The latter approach can be reasonably successful for E. coli isolates (since most are susceptible, even among hospital isolates) but has to be done with caution when treating other gramnegative species since CLSI interpretive criteria exist only for E. coli and Enterococcus faecalis urine isolates [21,30]. Some epidemiologic data have suggested that susceptibility to routinely tested agents like ciprofloxacin or TMP-SMX can be used as a marker for likely susceptibility to fosfomycin, but it is not uniform [5].…”

“…Clinicians considering treatment with TMP-SMX should carefully review an ambulatory patient's individual risk of MDR pathogenesis in addition to considering local resistance patterns prior to prescribing. In patients with UTIs caused by MDR pathogens, choosing an agent concordant with previous uropathogen microbiologic data may increase the chance of providing active empiric therapy [5].…”

“…Any patient (regardless of sex) considered to be at risk of having a UTI due to a multidrug-resistant (MDR) uropathogen (generally considered nonsusceptible to ≥1 agent in ≥3 antibiotic classes, though definitions may vary by institution) should have a urine culture performed as part of the initial assessment in order to tailor the empiric therapy and inform empiric antimicrobial selection in the case of future occurrences [4]. Use of prior microbiological susceptibility data from the same patient within the past 2 years may also be helpful in choosing an active agent [5]. A more detailed discussion of diagnostic approaches to UTIs is outside the scope of this review but is well outlined by others [2].…”

Surgical Antibiotic Prophylaxis and Risk for Postoperative Antibiotic-Resistant Infections

“…(39–41) Knowledge of an individual’s past culture data and related risk for antibiotic-resistant infection is a crucial part of appropriate antibiotic selection for a given patient. (40, 42, 43) A combined approach to SAP based on procedure-specific risks in conjunction with a patient’s own prior culture data could potentially serve to improve clinical outcomes.…”