Bloodstream Infections Caused by Gram-Negative Bacteria in Geriatric Patients: Epidemiology, Antimicrobial Resistance...

Bloodstream infections (BSIs) are an important cause of morbidity and mortality in geriatric patients. We retrospectively analyzed the cases of geriatric patients who developed BSIs due to gram-negative bacteria in order to evaluate the epidemiology, antimicrobial resistance, and the factors affecting mortality. The cases of 110 patients aged ≥ 65 years admitted to our hospital between January 1, 2017, and December 31, 2022 were assessed; 70 (63.6%) of the BSIs were healthcare-associated BSIs. The urinary system was the most common detectable source of infection at 43.6%. The most frequently isolated bacteria were Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae, in that order. Carbapenem resistance was detected in 17 patients (15.5%), and extended-spectrum beta-lactamase (ESBL) production from Enterobacterales family members was detected in 37 (51.4%) patients. Multivariate analysis revealed that (i) the probability of mortality in the patients with total bilirubin was increased by approx. sixfold and (ii) the likelihood of mortality for those with a Pitt bacteremia score (PBS) ≥ 4 points was approx. 17 times higher. PBS and simplified qPitt scores can help predict mortality and manage geriatric patients. There is a significant increase in mortality among patients with procalcitonin (PCT) levels at ≥ 2 nm/ml.