Third nationwide surveillance of bacterial pathogens in patients with acute uncomplicated cystitis conducted by the Japanese surveillance committee during 2020 and 2021: Antimicrobial susceptibility of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus saprophyticus

The Japanese surveillance committee conducted a third nationwide surveillance of antimicrobial susceptibility of acute uncomplicated cystitis at 55 facilities throughout Japan between April 2020 and September 2021. In this surveillance, we investigated the susceptibility of Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), and Staphylococcus saprophyticus (S. saprophyticus) for various antimicrobial agents by isolating and culturing bacteria from urine samples. In total, 823 strains were isolated from 848 patients and 569 strains of target bacteria, including E. coli (n = 529, 92.9 %), K. pneumoniae (n = 28, 4.9 %), and S. saprophyticus (n = 12, 2.2 %) were isolated. The minimum inhibitory concentrations of 18 antibacterial agents were determined according to the Clinical and Laboratory Standards Institute manual. In premenopausal patients, there were 31 (10.5 %) and 20 (6.8 %) fluoroquinolone (FQ)-resistant E. coli and extended-spectrum β-lactamase (ESBL)-producing E. coli, respectively. On the other hand, in postmenopausal patients, there were 75 (32.1 %) and 36 (15.4 %) FQ-resistant E. coli and ESBL-producing E. coli, respectively. The rate of FQ-resistant E. coli and ESBL-producing E. coli in post-menopausal women was higher than that for our previous nationwide surveillance (20.7 % and 32.1 %: p = 0.0004, 10.0 % and 15.4 %; p = 0.0259). For pre-menopausal women, there was no significant difference in the rate of FQ-resistant E. coli and ESBL-producing E. coli between this and previous reports, but the frequency of FQ-resistant E. coli and ESBL-producing E. coli exhibited a gradual increase. For appropriate antimicrobial agent selection and usage, it is essential for clinicians to be aware of the high rate of these antimicrobial-resistant bacteria in acute uncomplicated cystitis in Japan.