to assess the distribution of bacteremia pathogens in elderly patients, to evaluate the impact of gender on pathogen distribution, and to determine the predictive value of routine blood parameters for diagnosing bacteremia. Methods: A total of 151 elderly patients (≥60 years old) who admitted to hospital from October 2022 to June 2023 were retrospectively studied. Routine blood test and blood culture were performed. ROC curve was used to analyze the diagnostic efficacy of blood routine parameters: white blood cell (WBC), neutrophil-to-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), red blood cell distribution width (RDW). Results: The subjects were categorized into either the culture-positive group (82 cases) and the culture-negative one (69 cases) according to blood culture results. There were no significant differences in age and gender between groups. The primary bacterial pathogens of bacteremia in the elderly were Escherichia coli, Klebsiella pneumoniae and Streptococcus. A significantly higher culture positivity rate for E. coli was found in elderly female patients compared to their male counterparts (P = 0.021). The area under the ROC curve of four parameters was: WBC, 0.851 (95% confidence interval (CI) 0.790 - 0.912); NLR, 0.919 (95% CI 0.875 - 0.963); PLR, 0.609 (95% CI 0.518 - 0.700); and RDW was 0.626 (95% CI 0.563 - 0.717). Conclusion: The most frequently pathogenic microorganism causing bacteremia was E. coli, with elderly female patients having a significantly higher rate of culture positivity. Routine blood parameters (WBC, NLR, PLR, and RDW) demonstrated predictive potential for bacteremia in elderly patients.

Background: To investigate the distribution of bacterial pathogens of lower respiratory tract infection (LRTI) in hospitalized elderly patients during the COVID-19 epidemic and to explore the influence of COVID-19 on the distribution of bacterial pathogens, in order to provide guidance for clinical diagnosis. Methods: Specimens of sputum from elderly LRTIs patients at Fuding Hospital of China were collected from October 2022 to January 2023. Cultures and identification were done, and RT-PCR was employed to detect SARS-Cov-2 nucleic acid. Results: A total of 195 isolates were characterized in 163 sputum samples of consecutive hospitalized elderly patients, of which 11.3% were Gram-positive bacteria and 88.7% Gram-negative. The top of frequently isolated pathogens were Klebsiella pneumonia (30.3%), Pseudomonas aeruginosa (19.0%), Acinetobacter baumannii (12.8%), Stenotrophomonas maltophili, (7.7%), Escherichia coli (7.2%). According to the results of novel coronavirus nucleic acid detection, the 163 patients were divided into COVID-19 group and non-COVID control (CNT) group. The comparison of bacterial distribution between the groups revealed that Stenotrophomonas maltophilia was lower in the COVID-19 than in the CNT group, while Acinetobacter baumannii was higher in the COVID-19 group, and the difference was statistically significant (P < 0.05). Conclusion: The major bacteria identified in sputum culture of hospitalized elderly patients were Klebsiella pneumonia, Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and Escherichia coli. Furthermore, the distribution of Stenotrophomonas maltophilia and Acinetobacter baumannii between the COVID-19 and CNT groups was found to be significantly different (P< 0.05), while there were no significant differences in the distribution of other bacteria.