From the Guidelines
For this 41-year-old patient with recurrent UTI symptoms after Macrobid treatment, I recommend fosfomycin trometamol 3g in a single dose, as it is an appropriate choice for therapy due to minimal resistance and propensity for collateral damage, as stated in the 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases 1. This patient's sulfa allergy rules out trimethoprim-sulfamethoxazole, and the culture results showing E. coli resistant only to ampicillin make fosfomycin trometamol a suitable option. Key points to consider in this decision include:
- Fosfomycin trometamol has minimal resistance and a low propensity for collateral damage, making it a good choice for treating UTIs 1.
- The patient's history of hypercoagulable disorder and previous pulmonary embolism/DVT do not contraindicate fosfomycin trometamol use.
- Since the infection recurred after initial treatment with Macrobid (nitrofurantoin), switching to a different antibiotic class is prudent.
- Fosfomycin trometamol achieves high urinary concentrations, which is beneficial for treating UTIs that didn't fully resolve with prior therapy. The patient should be advised to stay well-hydrated and to follow up if symptoms persist after completing this course, as this could indicate a complicated UTI requiring further evaluation. It is essential to note that while fosfomycin trometamol appears to have inferior efficacy compared with standard short-course regimens, its advantages in terms of resistance and collateral damage make it a suitable choice for this patient 1.
From the FDA Drug Label
Ciprofloxacin is indicated for the treatment of complicated urinary tract infections and pyelonephritis due to Escherichia coli Although effective in clinical trials, ciprofloxacin is not a drug of first choice in the pediatric population due to an increased incidence of adverse events compared to the controls, including events related to joints and/or surrounding tissues. Urinary Tract Infections: For the treatment of urinary tract infections due to susceptible strains of the following organisms: Escherichia coli,
The patient has a sulfa allergy, and the urine culture grew E. coli.
- Ciprofloxacin is a possible choice for the treatment of this UTI, as it is indicated for the treatment of complicated urinary tract infections and pyelonephritis due to Escherichia coli 2.
- Trimethoprim (often used in combination with sulfamethoxazole) is also effective against E. coli, but the patient has a sulfa allergy, which may be a concern 3.
From the Research
Treatment Options for UTI
Given the patient's sulfa allergy and the urine culture results showing E. coli resistant to ampicillin, the following treatment options can be considered:
- Fluoroquinolones, such as ciprofloxacin or levofloxacin, which have been shown to be effective in treating UTIs, including those caused by E. coli 4, 5, 6
- Nitrofurantoin, which is a fluoroquinolone-sparing agent and can be used as an alternative to fluoroquinolones 5
- Fosfomycin, which is a second-line agent for empirical treatment of cystitis 5
Considerations for Patients with Sulfa Allergy
When managing patients with sulfa allergy, it is essential to consider the severity and certainty of the initial allergy, as well as the availability of alternative treatments 7, 8
- Cross-reactivity between sulfa antibiotics and nonantibiotics is rare, but can occur, and may affect the pharmacologic and clinical management of patients with sulfa allergy 8
- Readministration of a sulfonamide should not be attempted in patients who have had severe reactions, such as Stevens-Johnson syndrome, unless essential for survival 7
Choosing a Suitable Treatment
Based on the patient's history and the urine culture results, a fluoroquinolone, such as ciprofloxacin or levofloxacin, may be a suitable treatment option, considering the patient's sulfa allergy and the resistance pattern of the E. coli isolate 4, 5, 6