CTX-M-15-Producing Shigella sonnei Strain from a Czech Patient Who Traveled in Asia

Producing Shigella sonnei Strain from a Czech Patient Who Traveled in Asia ᰔInternational travel has been recognized as an important factor in the diffusion of multiresistant bacteria, including organisms that produce extended-spectrum ␤-lactamases (ESBLs) (14,15,16).When followed by clonal spread and/or horizontal transfer of ESBL-encoding plasmids in new areas, it may contribute to the global "epidemiologic success" of particular ESBL types.This is probably the case for some of the CTX-M enzymes (e.g., CTX-M-15), a family of derivatives of natural ␤-lactamases of Kluyvera spp.(3,12).Here we report the first identification of ESBL-producing Shigella sonnei in the Czech Republic, from a 31-year-old female who traveled to China, Nepal, and India in April and May 2006.Immediately after returning, she was admitted with diarrhea and vomiting to a regional hospital.S. sonnei was cultured from stool; the identification was performed by ENTEROtest 24 (Pliva-Lachema Diagnostika, Brno, Czech Republic) and Shigella sonnei Polyvalent D (Denka Seiken, Tokyo, Japan).The isolate was found to produce ESBL with the double-disk synergy test (10).MICs of various antimicrobials, determined by the CLSI microdilution method (5), showed a classical ESBL-mediated pattern of ␤-lactam resistance, including cefotaxime and ceftazidime (Table 1).The patient, not treated with antibiotics, recovered in 21 days.The isolate was subjected to mating with Escherichia coli A15 Rif r as previously described (8); cefotaxime-and rifampinresistant transconjugants were obtained at a frequency of 10 Ϫ4 per donor cell.Isoelectric focusing (2) revealed that both the S. sonnei isolate and its transconjugant expressed ␤-lactamases with pIs of 8.9 and 5.4, of which the pI 8.9 enzyme hydrolyzed cefotaxime and ceftazidime in the overlay assay (2).PCR with primers P1C and P2D, which are specific for bla CTX-M-1 -like genes (8), followed by DNA sequencing, identified the enzyme