CTX-M-32 beta-lactamase-producing uropathogenic Escherichia coli isolated in Latin America.

Background Uropathogenic Escherichia coli (UPEC) is the most important pathogen involved in urinary tract infections (UTIs). Beta-lactam antibiotics have been widely used to treat UPEC infections; however, extended-spectrum beta-lactamases (ESBLs) create significant therapeutic problems by inactivating almost all beta-lactams except cephamycins and carbapenems [1,2]. The CTX-M-type beta-lactamases are members of a lineage of ESBLs currently recognized as the most widespread worldwide, both in clinical and community settings. Based on their amino-acid sequence diversity, more than 135 of the CTX-M identified variants have been classified into six major clusters: CTX-M-1, -2, -8, -9, -25 and -45. (www.lahey.org/studies/webt.stm) [3-5]. These betalactamases predominantly hydrolyze cefotaxime (or ceftriaxone) but are weakly active against ceftazidime. However, to date the CTX-M-1 cluster is the most diversified group and includes more efficient CTX-M variants with a strong hydrolytic activity against ceftazidime, as is the case for CTX-M-32 [6]. In 2004, blaCTX-M-32 was first reported in an E. coli isolate from Spain [7]. Since then, CTX-M-32 continues to spread mainly in Mediterranean countries [3]. In Latin America, the prevalence of CTX-M beta-lactamases is represented by the CTX-M-2, but other variants such as CTX-M-1, CTX-M-8, CTX-M-9, CTX-M-12, CTX-M-14, CTX-M-15, CTX-M-16, CTX-M-24 and CTX-M-56 have been identified in this continent [4,8]. In this report, we describe the first detection of CTXM-32 in uropathogenic Escherichia coli from Venezuela, which is also the first report of this enzyme in Latin America.