[An analysis of the outbreak situation and background risk factors for drug-resistant urinary tract infection in nursing homes].

Aim: The present study clarified the outbreak situation and background risk factors for drug-resistant bacteria infection in nursing homes.

Methods: Subjects were 48 elderly individuals with urinary tract infections in 3 nursing homes during the 12-month period from January to December 2020. We analyzed the drug resistance of cultured bacteria using medical records.

Results: Escherichia coli was the most frequently cultured bacteria (37.1%), and extended-spectrum β-lactamase (ESBL) -producing E. coli accounted for 26.1% of specimens. E. coli susceptibility to levofloxacin (LVFX) was seen in 47.8%, resistance in 47.8%, and intermediate response in 4.4%. E. coli susceptibility to ceftriaxone (CTRX) was seen in 73.9%, and resistance in 26.1%. E. coli susceptibility to sulfamethoxazole trimethoprim (ST) mixture was seen 81.8%, while resistance was seen in 18.2%. In addition, among ESBL-producing E. coli, susceptibility to LVFX was seen in 0% and resistance in 83.3%, and an intermediate response was seen in 16.7%, while susceptibility to ST mixture was seen in 83.3% and resistance in 16.7%. No marked differences in background risk factors were seen between the groups with LVFX-resistant and LVFX-susceptible E. coli. However, the body mass index was significantly lower (p=0.0389), and significantly more patients were treated with antimicrobial agents during the 1-year period preceding the sample acquisition and analysis (p=0.0418) in the group with CTRX-resistant E. coli than in the group with CTRX-susceptible E. coli.

Conclusion: In the nursing homes examined, LVFX-resistant E. coli were highly prevalent, and ESBL-producing bacteria were also common. When we treat urinary tract infections, refraining from the use of LVFX is desirable, and antimicrobials should be chosen with care.