Clinical characteristics and risk of mortality of catheter-related bloodstream infections caused by Acinetobacter species: A multi-center study

• Main Authors: Lee, I, 李翊
• Other Authors: Lin, Jung-Chung
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/57879062818121995849

博士 === 國防醫學院 === 生命科學研究所 === 105 === Background Acinetobacter species are strictly aerobic, gram-negative, non-fermenting, oxidase-negative, catalase-positive, and non-motile coccobacilli, which have been increasingly reported as being associated with nosocomial infections. Acinetobacter spp. infections not only prolong the length of hospital stays but also results in high attributable mortality. Previous reports primarily focused on deaths from bacteremia and pneumonia; therefore, the risk of mortality from catheter-related bloodstream infections (CRBSIs) caused by Acinetobacter spp. remains obscure. The prevalence of CRBSIs caused by Acinetobacter spp. is increasing. The management of intravascular catheters in patients with bloodstream infections is affected by several factors, including the characteristics of the causative pathogens. However, because there have been limited studies elucidating the risk of mortality for CRBSIs caused by Acinetobacter spp., the outcome of patient health with early catheter removal in CRBSIs caused by Acinetobacter spp. remains unclear. Objectives Our study aimed to delineate the epidemiology and microbiological characteristics of bacteremia caused by Acinetobacter spp. These include risk factors, clinical and microbiological characteristics, antimicrobial resistances, formation of biofilm, treatment modality, and outcomes in multi-center setting. Second, to examine the risk of mortality and the effect of early catheter removal on survival of patients with CRBSIs caused by Acinetobacter spp. Materials and Methods This retrospective study was conducted at multiple centers in Taiwan including (alphabetically) Changhua Christian Hospital, Mackay Memorial Hospital, National Defense Medical Center, National Health Research Institute, Taichung Veterans General Hospital, Taipei Veterans General Hospital, and Tri-Service General Hospital from 2012-2014. Patients with at least one positive blood culture and one positive catheter culture for the same Acinetobacter spp. and who showed symptoms and signs of CRBSIs were included (n = 119). Risk factors for 30-day mortality were analyzed using a logistic regression model. The characteristics of patients with early catheter removal (within 48 hours after CRBSI diagnosis) were compared with those without catheter removal matching for age, sex, and disease severity. Results In this study, A. nosocomialis (51.3%) was found to be predominant, followed by A. baumannii (41.2%), A. pittii (6.7%) and A. soli (0.8%). A. baumannii was more resistant than the other species to most of the antimicrobial agents resulting in a higher multi-drug resistance rate. The 30-day mortality rate was highest in A. baumannii, followed by A. nosocomialis and the other Acinetobacter spp. (40.8%, 32.8%, 11.1%, respectively, p = 0.119). The 14-day mortality (35.4% vs. 6.9%, p < 0.001) and 30-day mortality (45.6% vs. 12.5%, p < 0.001) rates were significantly higher in CRBSI patients with CVCs (central venous catheters) than those with port or other catheter types. The 14-day mortality rate of CRBSI patients was significantly lower in patients infected with biofilm-forming isolates than in the patients infected with the biofilm-negative isolates (16.4% vs. 34.5%, p = 0.019). The proportion of A. baumannii was higher in the group of biofilm-negative CRBSI patients than in the biofilm-positive patients, while the proportion of A. nosocomialis was higher in the group of biofilm-positive CRBSI patients than in the biofilm-negative patients. The 14-day (21.6% vs. 47.6%, p = 0.016) and 30-day (33.4% vs. 57.1%, p = 0.022) mortality rates were significantly lower in the CRBSI patients with CVCs infected with biofilm-positive isolates than the patients infected with biofilm-negative isolates. There were no significant differences in 30-day mortality with regard to causative Acinetobacter spp., catheter type, catheter site, or appropriateness of antimicrobial therapy. Patients with higher Acute Physiologic and Chronic Health Evaluation APACHE II scores (odds ratio [OR] = 1.12; 95% confidence interval [CI]: 1.02-1.23), shock (OR = 6.43; 95% CI: 1.28-32.33), and longer hospitalization before CRBSI (OR = 1.04; 95% CI: 1.00-1.08) had a significantly higher 30-day mortality rate. Early removal of catheters after CRBSI diagnosis was not associated with better survival outcomes. Conclusion Higher disease severity, shock, and longer hospitalization before bacteremia were independently associated with a higher 30-day patient mortality rate in CRBSIs caused by Acinetobacter spp. The current results do not find that early removal of catheters improved survival outcome. Further well-controlled prospective studies are needed to clarify the outcomes of infections caused by Acinetobacter spp.