Asymptomatic bacteriuria in elderly humans is associated with increased levels of circulating TNF receptors and elevated numbers of neutrophils

Low-grade inflammatory activity is strongly associated with age-associated diseases such as atherosclerosis, dementia, type-2 diabetes, sarcopenia, and osteoporosis and predicts mortality risk in elderly populations. The aim of the current study was to investigate if asymptomatic bacteriuria in elderly humans was associated with inflammation. Midstream clean-catch urine culture was collected from consecutive, elderly patients at admission to a department of internal medicine due to functional disability. Forty patients (age 70-91 years) were selected and included in the current study; 20 subjects had positive urine culture and 20 sex- and age-matched subjects had negative urine culture. Inclusion criteria were temperature below 37.8°C, no clinical signs of infection and no current antibiotic treatment. Patients with asymptomatic bacteriuria had significantly increased levels of circulating tumor necrosis factor receptors (sTNFR-I) and a higher number of neutrophils in the blood compared to the group without bacteriuria. Thus, the present study provides some support for the hypothesis that asymptomatic urinary infections are associated with low-grade immune activity in frail, elderly humans.