Hospital acquired infections (HAI) in the elderly: comparison with the younger patients.

The aim of this retrospective study is to determine the frequency, type, microbiological characteristics and outcome of HAIs in the elderly (age ≥ 65) and to compare the data with younger patients in a Turkish Training and Research Hospital. From January 2008 to December 2009, the infection control team analyzed HAIs among 60,585 hospitalized patients (20,109 aged ≥ 65 and 40,747 aged between 18 and 64 years) with a total number of 419,017 patient days. A total of 825 HAIs episodes were detected in 607 patients, of which 395 episodes were in 301 elderly patients. The incidence of HAIs per 1000 patient days was 2.49 in the elderly and 1.64 in the younger patients' group (p<0.001). The most common site of infection in the elderly patients was the urinary tract, whereas in non-elderly group this was the lower respiratory tract. The incidence density of urinary tract infections, respiratory tract infections, surgical site, skin and soft tissue infections, primary bacteremia, and prosthesis infections were significantly higher in the elderly group (p<0.05). Gram-negative species were the most frequently isolated agents in both groups. There were no significant differences between the groups in the frequency of isolated pathogens or antibiotic susceptibility patterns. Overall, the fatality rate was found 16.8%. The elderly patients were more likely to have crude mortality rates (22% vs. 12%; p<0.01). The death was most often related to pneumonia, primary bacteremia or intravascular catheter infections in both groups.