Extended-spectrum cephalosporin-resistant escherichia coli in community, specialized outpatient clinic and hospital settings in Switzerland

摘要

Resistance to extended-spectrum cephalosporins (ESCs) in Escherichia coli can be due to the production of ESBLs, plasmid-mediated AmpCs (pAmpCs) or chromosomal AmpCs (cAmpCs). Information regarding type and prevalence of Β-lactamases, clonal relations and plasmids associated with the bla genes for ESC-R E. coli (ESCR- Ec) detected in Switzerland is lacking. Moreover, data focusing on patients referred to the specialized outpatient clinics (SOCs) are needed. We analysed 611 unique E. coli isolated during September-December 2011. ESC-R-Ecwere studied with microarrays, PCR/DNA sequencing for blaESBLs, blapAmpCs, promoter region of blacAmpC, IS elements, plasmid incompatibility group, and also implementing transformation, aIEF, rep-PCR and MLST. The highest resistance rates were observed in the SOCs, whereas those in the hospital and community were lower (e.g. quinolone resistance of 22.6%, 17.2% and 9.0%, respectively; P=40.003 for SOCs versus community). The prevalence of ESC-R-Ec in the three settings was 5.3% (n=411), 7.8% (n=422) and 5.7% (n=47), respectively. Thirty isolates produced CTX-M ESBLs (14were CTX-M-15), 5 produced CMY-2 pAmpC and 5 hyper-expressed cAmpCs due to promoter mutations. Fourteen isolates were of sequence type 131 (ST131; 10 with CTX-M-15). blaCTX-M and blaCMY-2 were associated with an intact or truncated ISEcp1 and were mainly carried by IncF, IncFII and IncI1plasmids. ST131 producing CTX-M-15 is the predominant clone. Theprevalence of ESC-R-Ec (overall 6.5%) is low, but an unusual relatively high frequency of Amp C producers (25%)was noted. The presence of ESC-R-Ec in the SOCs and their potential ability to be exchanged between hospital and community should be taken into serious consideration.