Background: Diverse sequence types (ST) and various carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) infections, which complicate treatment strategies, have emerged in Singapore. We aim to describe these CP-CRE infections and clinical outcomes according to their carbapenemase types and determine the hierarchy of predictors for mortality that are translatable to clinical practice.

Methods: Clinically significant CP-CRE infections were identified in Singapore General Hospital between 2013 and 2016. Retrospectively, all clinically relevant data were retrieved from electronic medical records from the hospital. Univariate analysis was performed. To further explore the relationship between the variables and mortality in different subsets of patients with CP-CRE, we conducted recursive partitioning analysis on all study variables using the “rpart” package in R.

Results: One hundred and fifty five patients were included in the study. Among them, 169 unique CP-CRE were isolated. Thirty-day all-cause in-hospital mortality was 35.5% (n = 55). There was no difference in the severity of illness, or any clinical outcomes exhibited by patients between the various carbapenemases. Root node began with patients with Acute Physical and Chronic Health Evaluation (APACHEII) score ≥ 15 (n = 98; mortality risk = 52.0%) and <15 (n = 57; mortality risk = 9.0%). Patients with APACHEII score ≥ 15 are further classified based on presence (n = 27; mortality risk = 23.0%) and absence (n = 71, mortality risk = 62.0%) of bacterial eradication. Without bacterial eradication, absence (n = 54) and presence (n = 17) of active source control yielded 70.0 and 35.0% mortality risk, respectively. Without active source control, the mortality risk was higher for the patients with non-receipt of definite combination therapy (n = 36, mortality risk = 83.0%) when compared to those who received (n = 18, mortality risk = 47.0%). Overall, the classification tree has an area under receiver operating characteristic curve of 0.92, with a sensitivity of 0.87 and specificity of 0.91.

Conclusion: Different mortality risks were observed with different treatment strategies. Effective source control and microbial eradication were associated with a lower mortality rate but not active empiric therapy for CP-CRE infection. When source control was impossible, definitive antibiotic combination appeared to be associated with a reduction in mortality.

背景： 多种序列类型（ST）和各种产生碳青霉烯酶的耐药性 肠杆菌（CP-CRE）感染使治疗策略复杂化，已经在新加坡出现。我们旨在根据其碳青霉烯酶类型描述这些CP-CRE感染和临床结局，并确定可转化为临床实践的死亡率预测指标的层次结构。

方法：在2013年至2016年之间，在新加坡总医院中发现了具有临床意义的CP-CRE感染。回顾性地，所有临床相关数据均从该医院的电子病历中获取。进行单因素分析。为了进一步探讨CP-CRE患者不同亚型中变量与死亡率之间的关系，我们使用R中的“ rpart”软件包对所有研究变量进行了递归划分分析。

结果：该研究包括155名患者。其中，分离出169种独特的CP-CRE。三十天全因医院死亡率为35.5％（ñ= 55）。各种碳青霉烯酶之间的疾病严重程度或患者表现出的任何临床结果均无差异。根结点始于急性物理和慢性健康评估（APACHEII）得分≥15（ñ= 98; 死亡率风险= 52.0％）和<15（ñ= 57; 死亡率风险= 9.0％）。APACHEII得分≥15的患者会根据在场情况进一步分类（ñ= 27; 死亡风险= 23.0％）和缺勤（ñ= 71，死亡风险= 62.0％）。不消灭细菌，不存在（ñ = 54）和状态（ñ= 17）的主动源控制分别产生70.0和35.0％的死亡风险。如果没有有效的来源控制，则未接受明确联合治疗的患者的死亡风险更高（ñ = 36，死亡风险= 83.0％）。ñ= 18，死亡风险= 47.0％）。总体而言，分类树在接收器工作特性曲线下的面积为0.92，灵敏度为0.87，特异性为0.91。

结论：使用不同的治疗策略观察到不同的死亡风险。有效的源控制和微生物根除与较低的死亡率相关，但对CP-CRE感染没有积极的经验治疗。当不可能进行源头控制时，确定的抗生素组合似乎可以降低死亡率。