Successful Doxycycline Therapy in a Patient With Escherichia coli and Multidrug-Resistant Klebsiella pneumoniae Urinary Tract Infection.

OBJECTIVE: To report on a patient with a symptomatic, polymicrobial Escherichia coli and multidrug-resistant (MDR), extended-spectrum β-lactamase (ESBL)-positive Klebsiella pneumoniae urinary tract infection (UTI) who was successfully treated with oral doxycycline hyclate.

CASE SUMMARY: A 70-year-old white male inpatient with a history of recurrent UTI, type 2 diabetes, hypertension, obesity, and diverticular disease was diagnosed with UTI and empirically treated with oral ciprofloxacin. Symptoms persisted 2 days later, and the patient was transitioned to amoxicillin/clavulanate by a different provider. The next day, upon receipt of the urine culture and susceptibility panel revealing E coli and MDR, ESBL-positive K pneumoniae infection, treatment was switched to doxycycline hyclate, which resulted in clinical improvement.

DISCUSSION: Complicated UTI involving multiple pathogens requires careful clinical judgment to select the appropriate antimicrobial agent, improve clinical outcomes, and prevent resistance. Treatment with doxycycline was based on the susceptibility panel and local resistance patterns. Advantages of doxycycline for UTI include its oral formulation, wide spectrum of activity, ability to achieve high concentration in the urine, and low toxicity.

CONCLUSION: Doxycycline hyclate may be an effective treatment option for patients with susceptible MDR UTI.