ABSTRACT
The incidence of urinary tract infections [UTIs] caused by extended-spectrum-?lactamase [ESBL] producing Escherichia coli [ESBLEC] and Klebsiella pneumoniae [ESBL-KP] has been on the rise limiting oral treatment options. Fosfomycin was reported to be highly efficacious against these organisms, however, data is lacking in Lebanon and the Middle East. To determine the in vitro activity of fosfomycin against ESBL and non-ESBL-producing E. coli and K. pneumoniae uropathogens in Lebanon. A total of 542 consecutive non-duplicate isolates of ESBL-producing E. coli [n = 374] and K. pneumoniae [n = 168], and 291 isolates of non-ESBLproducing E. coli [n = 236] and K. pneumoniae [n = 55] were recovered from urine specimens of patients tested at the American University of Beirut Medical Center [AUBMC] during 2010. Each isolate was tested against a battery of 13 antimicrobials by disk diffusion according to the guidelines of CLSI testing and result interpretation criteria. The fosfomycin susceptibility for ESBLproducing vs. non-ESBL-producing isolates was 86% vs. 97% for E. coli and 62% vs. 78% for K. pneumoniae. This activity of fosfomycin among ESBL-EC and ESBL-KP was generally higher than cefepime [26% and 30%], ciprofloxacin [24% and 41%], Trimeth/sulfa [26% and 19%], Pip/taz [75% and 45%], gentamicin [45% and 42%], and tobramycin [32% and 26%]. On the other hand, higher activity against both species of ESBLproducing bacteria was shown by amikacin [96% and 79%] and imipenem [99.7% and 98.8%]. Nitroflurantoin was highly active against ESBL-EC [95%] but not against ESBL-KP [29%]. Fosfomycin shows good activity, being higher against ESBL-producing E. coli than K. pneumoniae uropathogens in Lebanon