Urinary tract infections in elderly patients at a tertiary-care hosptial in Hungary: a 10-year study on their epidemiology and antibiotic resistance based on the WHO AWaRe classification

The ageing of the population – especially in developed countries – has brought on many societal challenges and has significantly contributed to the burden on healthcare infrastructures worldwide. Urinary tract infections (UTIs) are the third most common infections in humans, representing an important factor of morbidity, both among outpatients and hospitalized patients. The elderly are at a higher risk of developing UTIs, both due to anatomical and physiological changes, lifestyle factors, immobility and the frequent use of urinary catherers. A retrospective observational study was performed at a 1820-bed primary- and tertiary-care teaching hospital (University of Szeged) regarding the epidemiology and resistance of UTIs in patients aged ≥65 years. Identification of the isolates was carried out using VITEK 2 ID/AST and MALDI-TOF MS. Antibiotic resistance in these isolates was assessed based on the WHO AWaRe (Access, Watch, Reserve) classification of antimicrobials. During the 10-year study period, n=4214 (421.4±118.7/year) and n=4952 (495.2±274.6) laboratory-confirmed UTIs were recorded in inpatients and outpatients, respectively. The patients presented with the following demographic characteristics: a. outpatients: median age: 75 years (65-96), 39.7% male; b. inpatients: median age: 76 years (65-98), 71.3% male. The causative agents showed differentiation among inpatients and outpatients: Escherichia coli (25.7% vs. 48.1%; p=0.001), Enterococcus spp. (21.5% vs. 20.2%; p>0.05), Klebsiella spp. (16.3% vs. 16.2%; p>0.05), Pseudomonas spp. (13.4% vs. 4.4%; p=0.001); Proteus-Providencia-Morganella group (11.1% vs. 4.6%; p=0.001); Candida spp. (5.9% vs. 0.5%; p=0.001); Citrobacter-Enterobacter-Serratia group (2.9% vs. 1.8%; p<0.05). Significant differences were observed in the resistance rates among inpatient and outpatient isolates for many Access and Watch antibiotics; in addition, resistance rates were higher in these UTI pathogens, compared to the previously recorded rates in the region. Continuous surveillance of resistance rates in bacteria affecting vulnerable patient populations is needed for antimicrobial stewardship and to the ensure the selection of appropriate therapy in these patients.