CTX-M-15-producing Escherichia coli clinical isolates in Cairo (Egypt), including isolates of clonal complex ST10 and clones ST131, ST73, and ST405 in both community and hospital settings.

In Egypt, little is known about the genetic background of Escherichia coli isolates harboring extended-spectrum β-lactamase (ESBL). Five hundred twenty Enterobacteriaceae were prospectively collected (May 2007-August 2008) at the Theodor Bilharz Research Institute (Cairo). Among the collected Enterobacteriaceae, 56% (n=291) were E. coli and 32% (n=165) Klebsiella pneumoniae. A total of 16% (n=3) of all isolates were ESBL, 19% (n=55) of the E. coli and 14% (n=23) of the K. pneumoniae. The proportion of E. coli ESBL producers did not differ significantly between in and outpatients (20% vs. 17%) but was significantly different for non-E. coli ESBL producers (18.5% vs. 1.2%: p=0.0001). The majority of E. coli ESBL producers (75%) was isolated from urine. All the ESBL-producing Enterobacteriaceae available for molecular study (n=74) produced CTX-M-15. Among the CTX-M-15-producing E. coli isolates; 40% belonged to phylogenetic group A, 32% to D, and 26% to B2. ERIC-2 PCR profiles were obtained for all these E. coli isolates and multilocus sequence typing for those belonging to group B2. Genotyping analyses showed strain diversity; however, some clusters had profiles indistinguishable from that of previously published clones. Multilocus sequence typing showed that 75% of E. coli group B2 belonged to clone ST131. This indicates that a new country in Africa is adversely affected by clones of E. coli-producing CTX-M-15.