Characteristics of febrile urinary tract infections in older male adults.

Background: Urinary tract infections (UTI) are among the most frequent bacterial infections in older adults. The aim of the study was to analyse the existence of differences in clinical features, microbiological data and risk of infection by multidrug-resistant organisms (MDRO) between older and non-older men with febrile UTI (FUTI).

Methods: This was an ambispective observational study involving older males with a FUTI attended in the Emergency Department. Variables collected included age, comorbidity, diagnostic of healthcare-associated (HCA)-FUTI, clinical manifestations, hospitalization, mortality, and microbiological data.

Results: Five hundred fifty-two males with a FUTI, 329 (59.6%) of whom were older adults, were included. Older males had a higher frequency of HCA-FUTI (p <  0.001), increased Charlson scores (p <  0.001), had received previous antimicrobial treatment more frequently (p <  0.001) and had less lower urinary tract symptoms (p <  0.001). Older patients showed a lower frequency of FUTI caused by E. coli (p <  0.001) and a higher rate of those due to Enterobacter spp. (p = 0.003) and P. aeruginosa (p = 0.033). Resistance rates to cefuroxime (p = 0.038), gentamicin (p = 0.043), and fluoroquinolones (p <  0.001) in E. coli isolates and the prevalence of extended-spectrum beta-lactamase and AmpC producing E. coli and Klebsiella spp. strains (p = 0.041) and MDRO (p <  0.001) were increased in older males. Inadequate empirical antimicrobial treatment (p = 0.004), frequency of hospitalization (p <  0.001), and all cause in-hospital mortality (p = 0.007) were higher among older patients. In the multivariate analysis, being admitted from an long term care facility (OR 2.4; 95% CI: 1.06-5.9), having a urinary tract abnormality (OR 2.2; 95% CI: 1.2-3.8) and previous antimicrobial treatment (OR 3.2; 95% CI: 1.9-5.4) were associated to FUTI caused by MDRO.

Conclusions: Older male adults with a FUTI have different clinical characteristics, present specific microbiological features, and antimicrobial resistance rates. In the multivariate analysis being an older male was not associated with an increased risk of FUTI caused by MDRO.