关键词:

血流感染, 初始样本转移技术, 老年骨折患者, 血培养污染, 抗菌管理

Abstract:

Objective　To investigate the effect of initial sample transfer technique in reducing blood culture contamination rate in elderly patients with fractures without specified equipment or procedures. Methods　Four hundred elderly patients with fractures who were hospitalized in Department of Orthopedics, Tengzhou Central People's Hospital from January 2019 to March 2023 and needed to collect blood culture samples due to suspected or confirmed bloodstream infection were selected for the randomized control trial, and were divided into a control group and an observation group by the random number table method. In the control group, there were 204 patients (86 males and 118 females); they were 61 to 99 (81.74±7.96) years old; 72 cases suffered upper limb fractures, 90 cases lower limb fractures, 30 cases spine fractures, and 12 cases pelvis and acetabular fractures. In the observation group, there were 196 patients (90 males and 106 females); they were 60 to 94 (80.36±8.23) years old; 64 cases suffered upper limb fractures, 88 cases lower limb fractures, 34 cases spinal fractures, and 10 cases pelvic and acetabular fractures. The blood of the control group was collected by the standard method. The initial specimen diversion technique was used for blood collection in the observation group. The baseline data, true positive rates, and contamination rates of blood cultures were compared between the two groups. The microbiological characteristics of positive blood cultures and the proportion of each strain were analyzed. Independent sample t test, χ² test, or Fisher's exact test were used. Results　There was no statistical difference in the true positive rate of blood culture between the two groups (χ²=0.249, P>0.05). The contamination number/rate in the observation group was significantly lower than that in the control group [0.51% (1/196) vs. 4.90% (10/204)], with a statistical difference (χ²=7.209, P<0.05). Most of the strains isolated from the contaminated blood cultures in both groups were coagulase-negative staphylococcus; the most common cause of true bacteremia was Enterobacteriaceae species, followed by Staphylococcus aureus. The rate of intravenous vancomycin injection in the patients with blood culture contamination was significantly higher than that in the patients with negative blood cultures, with a statistical difference (P<0.05). The rate of additional blood culture extraction in the patients with blood culture contamination [63.64% (7/11)] was 39.87% higher than that in the patients with negative blood culture [23.77%(82/345)], with a statistical difference (χ²=7.036, P<0.05). The mean hospital stay in the patients with blood culture contamination was 2.97 d (95%CI 1.5-3.0 d) days longer than that in the patients with negative blood cultures. Conclusions　The use of initial specimen diversion technique can significantly reduce blood culture contamination without affecting the true positivity of blood cultures. This novel approach is practical and safe for patients as a simple and effective measure that does not compromise the sensitivity of blood cultures and does not need expensive equipment.

Key words:

Bloodstream infection, Initial specimen diversion technique, Elderly patients with fractures, Blood culture contamination, Antibacterial management