Assessment of co-resistance to antibiotics recommended for acute pyelonephritis among Escherichia coli clinical strains from community- and nursing home-acquired urinary tract infections.

Objectives: This study aimed to assess the frequency of co-resistance to antibiotics recommended in acute pyelonephritis among Escherichia coli clinical strains isolated from urinary tract infections (UTIs) acquired in community or nursing homes (NHs), and to identify situations without alternatives to fluoroquinolones (FQs).

Methods: All antimicrobial susceptibility test (AST) results of E. coli culture-positive urine samples from females living in the community or in NHs, collected through a large network of clinical laboratories in 2020 in France, were included. The percentages of strains resistant to amoxicillin alone or combined with a resistance to one to four alternatives among amoxicillin/clavulanic acid, trimethoprim/sulfamethoxazole, cefixime and FQs were calculated and compared between age categories and settings.

Results: Among 291 367 E. coli strains from community-acquired UTIs, 60.3% were susceptible to amoxicillin (<65-year-olds: 61.8% versus ≥65-year-olds: 58.8%; P < 0.001), and 99.1% to oral alternatives to FQs. Co-resistance to amoxicillin and trimethoprim/sulfamethoxazole was higher among females ≥65 years old versus <65 years old (7.1% versus 6.1%; P < 0.01), as well as co-resistance to amoxicillin, amoxicillin/clavulanic acid and trimethoprim/sulfamethoxazole (8.6% versus 10%; P < 0.001). Among 11 340 strains from NH UTIs, 51.2% were susceptible to amoxicillin, and 98% to oral alternatives to FQs. Co-resistance to amoxicillin, amoxicillin/clavulanic acid and/or cefixime was higher in isolates from females ≥65 years old living in NHs versus in the community (respectively 11.9% versus 15.3%, P < 0.001; 0.8% versus 2.8%, P < 0.01; 1.7% versus 4.4%, P < 0.01).

Conclusions: Based on AST results, prescribing oral alternatives to FQs for females may be possible in ≥99% of E. coli acute pyelonephritis cases in the community, and ≥98% in NHs.