Blood-Stream Infections: Causative Agents, Antibiotic Resistance and Associated Factors in Older Patients.

Background: The rate of multi-drug antibiotic resistance in nosocomial bloodstream infections in elderly patients is increasing. This study examined the data for bloodstream infections to gain a better understanding of bacterial antibiotic resistance.

Methods: This was a retrospective study of 817 patients with the first positive blood culture between January 1, 2016 and December 31, 2019.

Results: Moyen's age was 77.4 ± 9.8 years, male (52.4%) and SOFA 5.0 ± 4. ESBL(+) rate was 78/817 (9.5%). ESBL(+) rate for Escherichia coli and Klebsiella pneumoniae was 69/141 (48.9%) and 9/52 (17.3%), respectively. The most common isolates were Escherichia coli (17.3%), Stenotrophomonas maltophilia (13.7%), and Staphylococcus species (23.1%). The rate of septic shock and mortality accounted for 22.3% and 28.9%, respectively. Escherichia coli is highly sensitive to carbapenem, and resistant (>50%) with quinolone and aminoside. Klebsiella pneumoniae and Pseudomonas aeruginosa were highly sensitive to carbapenem. Acinetobacter baumannii was resistant to meropenem (75%). Stenotrophomonas maltophilia was sensitive to quinolone (13.8 %), and highly resistant to remaining antibiotics. Methicillin-resistant Staphylococcus aureus had a low resistance rate for vancomycin, teicoplanin, and linezolid. Multivariate analysis showed that the significant factors associated with mortality were age >75; SOFA >7; respiratory infection; intensive care unit treatment and presentation with septic shock.

Conclusion: The mortality rate was still high, especially for antibiotic-resistant agents.