| Objective: To investigate the microbial characteristics and the drug resistance of the strains isolated from blood cultures in elderly patients with bloodstream infection. To identify the risk factors of 90-day all-cause mortality.Methods: Clinical data of patients aged ≥ 60 years, diagnosed as bloodstream infection, and admitted to department of geriatric in Tianjin General Hospital from January 1st, 2013 to December 30 th, 2015 were enrolled. Based on the prognosis of bloodstream infection, patients were divided into survival group and non-survival group to investigate the clinical and microbial characteristics of patients. Multiple logistic regression was conducted to identify the independent risk factors for 90-day all-cause mortality. SPSS software was used in the data analysis. P-values of less than 0.05 were accepted as statistically significant.Results: Totally we included 160 cases of bloodstream infection, one hundred and twenty five patients were male, thirty five patients were female and the mean age was 85.97±6.17 years. Thirty(18.8%) patients were polymicrobial bloodstream infection. Gram-positive bacteria, Gram-negative bacteria, fungi took accounts for 40.9%, 41.5%, 17.6% respectively. The five most common isolates were coagulase-negative staphylococcus(24.4%), E.coli(15.0%), Candida parapsilosis(14.5%), Enterococcus faecium(5.7%) and Klebsiella pneumoniae(5.2%). The detection rates of Methicillin-resistant coagulase-negative staphylococci and Methicillin-resistant Staphylococcus aureus were 93.6%, 75.0%, respectively. No resistant strains found in staphylococcus aureus to rina thiazole amine and vancomycin. 1 strain resistant of excrement enterococcus was detected to vancomycin. ESBLs positive rates of Escherichia coli and Klebsiella pneumoniae were 65.5%, 45.5% respectively. One strain resistant of enterobacter cloacae was detected to ertapenem. The common sources of BSI were central venous catheter, respiratory tract and urinary tract. The 90-day all-cause mortality rate was 33.1%. Compared with survival group, patients in non-survival group had higher incidence of polymicrobial infection, chronic pulmonary disease, kidney disease, malignancy and hypoproteinemia, higher proportion of using invasive mechanical ventilation and parenteral nutrition, higher proportion indwelling central venous catheter and trachea cannula/tracheotomy(P<0.05). Multiple logistic regression analysis showed that advanced age(OR=1.159,95%CI 1.070~1.255,P=0.000), polymicrobial infection(OR=4.606,95%CI 1.526~13.903,P=0.007), trachea cannula / tracheotomy(OR=4.144,95%CI 1.449~11.858,P=0.008) and hypoproteinemia(OR=3.530,95%CI 1.458~8.550,P=0.005) were the independent risk factors for 90-day all-cause mortality in elderly patients with bloodstream infection.Conclusions: 1.The common pathogens of bloodstream infection in elderly patients were coagulase-negative staphylococcus, E.coli, Candida parapsilosis, Enterococcus faecium, and Klebsiella pneumoniae. 2. The detection rate of Methicillin-resistant strain in staphylococcus was high. No resistant strains found in staphylococcus aureus to rina thiazole amine and vancomycin. Enterobacteriaceae bacteria are highly sensitive to penicillium carbon alkene antibiotics. 3. The common sources of BSI were central venous catheter, respiratory tract and urinary tract. 4. The 90-day all-cause mortality rate were 33.1%. 5. Advanced age, polymicrobial infection, trachea cannula/tracheotomy and hypoproteinemia were the independent risk factors for 90-day all-cause mortality in elderly patients with bloodstream infection. |
