Objectives: Fluoroquinolone resistance (FQR) in third-generation  cephalosporin-resistant Enterobacteriaceae (3GCRE) presents serious  limitations to antibiotic therapy. The aim of this study was to  investigate whether the FQR proportion among 3GCRE differs between  community-acquired (CA) and hospital-acquired (HA) isolates.

Methods:  In a prospective observational study covering 2014 and 2015, we  monitored the occurrence of 3GCRE in adult hospitalized patients in six  German university hospitals. 3GCRE clinical isolates were subdivided  into CA and HA. Multivariable analysis identified factors associated  with in vitro non-susceptibility to ciprofloxacin.

Results:  The dataset included 5721 3GCRE isolates of which 52.9% were HA  and 52.7% exhibited FQR. Interestingly, the FQR proportion was higher in  CA 3GCRE than in HA 3GCRE (overall, 60.1% versus 46.2%, respectively, P  < 0.001). Multivariable analysis adjusting for age confirmed  community acquisition as a risk factor for FQR [adjusted rate ratio  (aRR) 1.33, 95% CI 1.17-1.53]. Escherichia coli and Klebsiella spp. were  associated with a much higher FQR proportion than other  Enterobacteriaceae species (aRR 8.14, 95% CI 6.86-9.65 and aRR 7.62 with  95% CI 6.74-8.61, respectively).

Conclusions:  The high FQR proportion observed among CA 3GCRE, particularly in  E. coli and Klebsiella spp., indicates that selection pressure in the  outpatient setting needs to be addressed with antibiotic stewardship and  other interventions in order to limit further spread of MDR.