In total, 73 consecutive non-duplicate ESBL-positive E. coli and 72 K. pneumoniae strains were isolated.
The blaCTX-M-15 gene was found to be highly prevalent (69/73 strains, 94.5%) among the 73 ESBL-positive E. coli
isolates. The gene was detected in both clonal and non-clonal isolates, as defined by PFGE and rep-PCR. Sixteen
CTX-M-15-positive E. coli could be assigned to a single rep-PCR type and phylogenetic group B2 and belonged to
the well-known O25b-ST131 clone. Among the 72 ESBL-positive K. pneumoniae isolates, blaCTX-M-15 was again
the most prevalent ESBL (40/72, 55.6%). Several SHV-type enzymes were also frequently detected: SHV-5
(n¼28); SHV-12 (n¼13); and SHV-2 (n¼6). TEM-type ESBLs were not detected in any of the isolates.