Prevalence of fosfomycin resistance among ESBL-producing Escherichia coli isolates in the community, Switzerland

AbstractOur aim was to evaluate the prevalence of fosfomycin-resistant strains among ESBL-producingEscherichia coli isolates recovered from community patients in Switzerland. A total of 1225 ESBL-producingE. coli isolates were collected between 2012 and 2013 from a private and community laboratory. Fosfomycin resistance was assessed by using the novel rapid fosfomycin/E. coli NP test and agar dilution method. Resistant isolates were further investigated for acquired resistance genesfosA1 –7 by PCR and sequencing. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to evaluate the clonal relationship amongfosA3-carrying isolates. Out of the 1225 ESBL-producingE. coli isolates analyzed in this study, 1208 were fosfomycin susceptible while 17 were fosfomycin resistant. No discrepancy was observed between the rapid fosfomycin/E. coli NP test and the agar dilution method taken as the gold standard. Five out of the 17 resistant isolates carried afosA-like gene. No clonal relationship was observed among those isolates. Here, the prevalence of fosfomycin resistance among ESBL-producingE. coli isolates in the community is reported for the first time in Switzerland, being ca. 1.4%. Among the five isolates carrying afosA gene, four encoded the FosA3 enzyme, being the most prevalent fosfomycin-resistant determinant. An excellent correlation was observed between minimum inhibitory concentration –based susceptibility categorization and results o...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research