What is the recommended treatment for a patient with a urinary tract infection (UTI) prescribed Bactrim (trimethoprim/sulfamethoxazole) and a concurrent foot infection, previously prescribed doxycycline, which was never initiated?

From the Guidelines

I strongly recommend completing the full course of Bactrim DS (trimethoprim-sulfamethoxazole) as prescribed for the urinary tract infection, and initiating the doxycycline prescription for the foot infection, as the benefits of treating both infections simultaneously outweigh the risks of potential interactions or complications, according to the most recent guidelines 1.

Treatment Approach

When considering the treatment of a patient with a urinary tract infection (UTI) and a concurrent foot infection, it is essential to prioritize the use of evidence-based guidelines to minimize morbidity, mortality, and improve quality of life.

• The patient is already prescribed Bactrim (trimethoprim/sulfamethoxazole) for the UTI, which is an appropriate choice given its efficacy and the low resistance rates of uropathogens, as recommended by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases 1.
• For the foot infection, doxycycline is a suitable option, considering its effectiveness against a broad range of bacteria, including those commonly causing foot infections in patients with diabetes, as suggested by the IWGDF/IDSA guidelines 1.

Key Considerations

• Antibiotic Stewardship: It is crucial to practice antibiotic stewardship by selecting the narrowest spectrum antibiotic, with the shortest duration, fewest adverse effects, safest, and least expensive route, as emphasized in the IWGDF/IDSA guidelines 1.
• Concurrent Treatment: Treating both infections simultaneously is recommended, rather than sequentially, to prevent worsening infections or complications, and to ensure complete eradication of the infections and prevent antibiotic resistance.
• Patient Education: Patients should be educated on the importance of completing the full antibiotic course, even if symptoms improve before finishing, and advised to stay well-hydrated, take doxycycline with food to prevent stomach upset, and avoid sun exposure while on doxycycline due to increased photosensitivity.

Evidence-Based Recommendations

• The choice of antibiotic regimen should be based on the likely or proven causative pathogen(s) and their antibiotic susceptibilities, availability of the antibiotic, published evidence of efficacy, clinical severity of the infection, and patient-related factors, as recommended by the IWGDF/IDSA guidelines 1.
• The most recent guidelines suggest that no antibiotic class or agent has been found to be superior to others for treating diabetes-related foot infections, except in specific cases, and that the use of carbapenems and vancomycin should be cautious due to the risk of adverse events and antibiotic resistance 1.

From the FDA Drug Label

To reduce the development of drug-resistant bacteria and maintain the effectiveness of sulfamethoxazole and trimethoprim tablets and other antibacterial drugs, sulfamethoxazole and trimethoprim tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria Urinary Tract Infections: For the treatment of urinary tract infections due to susceptible strains of the following organisms: Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis and Proteus vulgaris It is recommended that initial episodes of uncomplicated urinary tract infections be treated with a single effective antibacterial agent rather than the combination

The recommended treatment for a patient with a urinary tract infection (UTI) prescribed Bactrim (trimethoprim/sulfamethoxazole) is to use it as a single effective antibacterial agent, as it is indicated for the treatment of urinary tract infections due to susceptible strains of certain organisms.

• The patient's concurrent foot infection and previous prescription of doxycycline, which was never initiated, do not affect the treatment of the UTI with Bactrim, as the drug label does not provide information on the treatment of foot infections or interactions with doxycycline in this context 2.
• Key consideration: The treatment should be based on the susceptibility of the bacteria causing the UTI.
• Main idea: Bactrim can be used to treat the UTI, but the effectiveness depends on the susceptibility of the bacteria.

From the Research

Treatment of Urinary Tract Infections (UTIs)

The patient has been prescribed Bactrim (trimethoprim/sulfamethoxazole) for a UTI and has a concurrent foot infection, for which doxycycline was previously prescribed but not initiated.

• The recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females is a 5-day course of nitrofurantoin, a 3-g single dose of fosfomycin tromethamine, or a 5-day course of pivmecillinam 3.
• However, high rates of resistance to trimethoprim-sulfamethoxazole preclude its use as empiric treatment of UTIs in several communities, particularly if patients were recently exposed to them or are at risk of infections with extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriales 3.
• Single-dose therapy with trimethoprim-sulfamethoxazole has been shown to be effective in treating UTIs in women, with a 93% eradication rate of infections 4.
• The use of prophylactic antibiotics, including trimethoprim/sulfamethoxazole, has been shown to be effective in reducing recurrent UTI episodes, emergency room visits, and hospital admissions due to UTIs 5.

Considerations for Concurrent Foot Infection

• The patient's concurrent foot infection, for which doxycycline was previously prescribed but not initiated, should be considered when determining the appropriate treatment for the UTI.
• There is no direct evidence in the provided studies to suggest that the concurrent foot infection would affect the treatment of the UTI.

Treatment Options

• Based on the provided evidence, alternative treatment options for the UTI could include nitrofurantoin, fosfomycin tromethamine, or pivmecillinam, considering the patient's health status and local susceptibility patterns 3.
• The use of trimethoprim-sulfamethoxazole may not be the best option due to potential resistance issues, but it has been shown to be effective in some cases 4, 6, 7.