Sensitivity of major causative urinary tract infection bacteria to various antimicrobial agents

We studied causative bacteria type and distribution by disease and sensitivity to antimicrobial agents, and risk factors for detecting quinolone-resistant Escherichia coli in case of acute uncomplicated cystitis or complicated cystitis and urine-sample bacteria isolation and cultivation. We isolated 1,699 strains from 1,317 subjects with acute uncomplicated cystitis, including E. coli (58.9%), Enterococcus faecalis (13.4%), Streptococcus agalactiae (4.6%), Klebsiella pneumoniae (3.6%), and Staphylococcus epidermidis (3.4%). We also isolated 880 from 643 with complicated cystitis, including E. coli (34.7%), E. faecalis (19.9%), Pseudomonas aeruginosa (4.9%), K. pneumoniae (4.9%), and S. agalactiae (4.5%). The sensitivity of E. coli isolated from acute uncomplicated cystitis for fluoroquinolone (FQs) and cephem (CEPs) agents was ≥90%. The sensitivity of E. coli isolated from complicated cystitis for FQs was 67.5-86.9%, showing the highest sensitivity for STFX. The sensitivity for CEPs was 83.9-88.5%. A study of risk factors for detecting quinolone-resistant E. coli (MIC of LVFX ≥4 μg/mL), significant differences were observed for cases involving the following 5 items: ≥2 cystitis episodes within 1 year (p<0.0001), a quinolone agent was ineffective against cystitis (p < 0.0001), complicated cystitis (p = 0.0009), a history of quinolone treatment within 1 month (p = 0.0054), and subjects 75 years or older (p = 0.0251). Our study of bacterial strains isolated from those with definite clinical disease diagnosis, showed cystitis-causing bacteria type and distribution with the highest incidence among urinary tract infections. Antimicrobial sensitivity varied greatly with the disease and subject. It is thus important to confirm the antimicrobial sensitivity of causative bacteria to maximize antimicrobial agent effectiveness. Appropriate antimicrobial agents must also be selected by carefully considering subject summaries and other factors in empiric therapy.