Li Shuang, Jia Xiaojiong, Li Congya, Zou Hua, Liu Hang, Guo Yuanbiao, Zhang Liping
Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China,
Medical Research Center, The Second Chengdu Hospital Affiliated to Chongqing Medical University, Chengdu, China,
Infect Drug Resist. 2018 Aug 20;11:1225-1235. doi: 10.2147/IDR.S174876. eCollection 2018.
is recognized as a major cause of severe and potentially life-threatening infection. However, isolates with the phenotype of being carbapenem resistant and cephalosporin susceptible (Carb-R/Ceph-S) have not been thoroughly characterized to date. The aim of this study was to assess the mechanisms, risk factors, and clinical impact of Carb-R/Ceph-S bacteremia on mortality.
We conducted a retrospective case-case-control study of the risk factors and clinical outcomes of hospitalized patients with Carb-R/Ceph-S bacteremia from 2011 to 2017 in Chongqing, China. Case patients infected with Carb-R/Ceph-S , carbapenem-susceptible and cephalosporin-susceptible (Carb-S/Ceph-S) , and controls with no bacteremia were compared at a ratio of 1:1:2. Real-time reverse transcription polymerase chain reaction was performed to assess resistance mechanisms. A multivariate logistic regression model was performed to investigate several potential predictors for mortality.
We collected 63 Carb-R/Ceph-S isolates during the study period. None of these isolates possessed carbapenemase or extended-spectrum β-lactamase-encoding genes. The overall 30-day mortality rate was 27.0%. Real-time reverse transcription polymerase chain reaction analysis showed that an overexpression of efflux systems and decreased expression of OprD were associated with Carb-R/Ceph-S . Multivariate analysis indicated that 30-day readmission, central venous catheters, and exposure to carbapenems were unique independent predictors for acquiring Carb-R/Ceph-S bacteremia. Additionally, hematologic malignancy was a peculiar predictor for Carb-S/Ceph-S bacteremia. Notably, total parenteral nutrition was the only common factor of both Carb-R/Ceph-S and Carb-S/Ceph-S groups compared to controls. In a multivariate analysis for the outcome, intensive care unit admission and septic shock were identified as the independent predictors for mortality.
Our findings can potentially improve the ability of physicians to identify the high-risk patients, and carbapenems were noted to potentially increase the risk of Carb-R/Ceph-S . Additionally, cephalosporin should be considered a valuable therapeutic option for such cases of bacteremia.
被认为是严重且可能危及生命的感染的主要原因。然而，具有碳青霉烯耐药和头孢菌素敏感（Carb-R/Ceph-S）表型的分离株迄今尚未得到充分表征。本研究的目的是评估Carb-R/Ceph-S菌血症的机制、危险因素及其对死亡率的临床影响。
我们对2011年至2017年在中国重庆住院的Carb-R/Ceph-S菌血症患者的危险因素和临床结局进行了一项回顾性病例-病例对照研究。将感染Carb-R/Ceph-S、碳青霉烯敏感和头孢菌素敏感（Carb-S/Ceph-S）的病例患者与无菌血症的对照患者按1:1:2的比例进行比较。采用实时逆转录聚合酶链反应评估耐药机制。进行多变量逻辑回归模型以研究死亡率的几个潜在预测因素。
在研究期间，我们收集了63株Carb-R/Ceph-S分离株。这些分离株均未携带碳青霉烯酶或超广谱β-内酰胺酶编码基因。总体30天死亡率为27.0%。实时逆转录聚合酶链反应分析表明，外排系统的过表达和OprD表达的降低与Carb-R/Ceph-S有关。多变量分析表明，30天再入院、中心静脉导管以及碳青霉烯类药物暴露是获得Carb-R/Ceph-S菌血症的独特独立预测因素。此外，血液系统恶性肿瘤是Carb-S/Ceph-S菌血症的一个特殊预测因素。值得注意的是，与对照组相比，全胃肠外营养是Carb-R/Ceph-S组和Carb-S/Ceph-S组唯一的共同因素。在对结局的多变量分析中，入住重症监护病房和感染性休克被确定为死亡率的独立预测因素。
我们的研究结果可能会提高医生识别高危患者的能力，并且注意到碳青霉烯类药物可能会增加Carb-R/Ceph-S的风险。此外，对于此类菌血症病例，应考虑将头孢菌素作为一种有价值的治疗选择。
