You have a patient sent by her PMD for a UTI. She had just received her culture results showing ESBL that is susceptible only to carbapenems. The PMD wants her admitted for IV antibiotics. She has no other symptoms. Is there a way to avoid this admission?

ESBL (extended-spectrum beta-lactamases) producing organisms are resistant to most beta-lactams including cephalosporins and aztreonam. They are found in gram-negative organisms such as Klebsiella, E Coli, Enterobacter, and Pseudomonas. ESBL-producing organisms have been found around the world, at times in the community, and even in supermarket meats and the River Thames.

Carbapenems have shown the best outcomes in severe infections (tigecycline may be another option). Failure is more likely with antibiotics such as cefepime, zosyn, and quinolones. So what could you use for outpatient therapy?

Since this is a purely lower GU tract infection, one option is fosfomycin. Fosfomycin is an older drug that has fallen out of use (~40 years old), but given the limited therapies for ESBL is now being looked at again. It is usually administered as a single oral dose and has rare adverse reactions. According to a review article, other possible treatments for UTI’s may potentially include nitrofurantoin, pivmecilliname, and co-amoxiclav.

In this case, we ran the idea by ID and they approved of the plan and the patient went home. Recent urology literature is also looking at fosfomycin for similar situations.

Munoz-Price, LS; Jacoby, GA. Extended-spectrum beta-lactamases. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on February 13, 2015.)

Falagas ME, Kastoris AC, Kapaskelis AM, Karageorgopoulos DE. Fosfomycin for the treatment of multidrug-resistant, including extended-spectrum beta-lactamase producing, Enterobacteriaceae infections: a systematic review. Lancet Infect Dis. 2010 Jan;10(1):43-50.

Sultan A, Rizvi M, Khan F, Sami H, Shukla I, Khan HM. Increasing antimicrobial resistance among uropathogens: Is fosfomycin the answer? Urol Ann. 2015 Jan-Mar;7(1):26-30.