Abstract：
OBJECTIVE: The aim of this study was to describe our experience of a combination treatment including meropenem/vaborbactam (M/V) plus aztreonam (ATM) for bloodstream infections (BSIs) due to ceftazidime/avibactam-resistant Klebsiella pneumoniae (CAZ/AVI-R-Kp), for which gene typing was not available at the time the blood culture (BC) results were obtained.
METHODS: Between 20 July and 22 August 2021, in our hospital laboratory, the molecular test for carbapenemase gene typing was not available. All Gram-negative bloodstream infections were recorded, and characteristics of patients were analysed. Among them, three patients had positive BCs for CAZ/AVI-R-Kp, and the empirical therapy was switched to M/V plus ATM pending phenotypic testing of sensitivity to M/V. Therapy was subsequently targeted on the basis of the results of this test.
RESULTS: KPC and NDM represent the most prevalent carbapenemases in our polyclinic. Three patients with CAZ/AVI-R-Kp sepsis were treated with M/V plus ATM not knowing the carbapenemase gene. Two had an NDM-Kp infection for which, upon obtaining the result of sensitivity to M/V, combination therapy was maintained. The third had KPC-Kp infection for which ATM was discontinued, after the acquisition of an antibiogram reporting full sensitivity to M/V (MIC = 0.25 mg/L). One patient with NDM-Kp infection died due to complications of the underlying disease for which he was hospitalised.
CONCLUSIONS: Meropenem/vaborbactam plus ATM and subsequent de-escalation could represent a possible therapeutic strategy in severe CAZ/AVI-R-Kp infections when carbapenemase gene typing is not rapidly available.
METHODS: Between 20 July and 22 August 2021, in our hospital laboratory, the molecular test for carbapenemase gene typing was not available. All Gram-negative bloodstream infections were recorded, and characteristics of patients were analysed. Among them, three patients had positive BCs for CAZ/AVI-R-Kp, and the empirical therapy was switched to M/V plus ATM pending phenotypic testing of sensitivity to M/V. Therapy was subsequently targeted on the basis of the results of this test.
RESULTS: KPC and NDM represent the most prevalent carbapenemases in our polyclinic. Three patients with CAZ/AVI-R-Kp sepsis were treated with M/V plus ATM not knowing the carbapenemase gene. Two had an NDM-Kp infection for which, upon obtaining the result of sensitivity to M/V, combination therapy was maintained. The third had KPC-Kp infection for which ATM was discontinued, after the acquisition of an antibiogram reporting full sensitivity to M/V (MIC = 0.25 mg/L). One patient with NDM-Kp infection died due to complications of the underlying disease for which he was hospitalised.
CONCLUSIONS: Meropenem/vaborbactam plus ATM and subsequent de-escalation could represent a possible therapeutic strategy in severe CAZ/AVI-R-Kp infections when carbapenemase gene typing is not rapidly available.
摘要：
目的：这项研究的目的是描述我们的经验，包括美罗培南/沃博巴坦（M/V）联合氨曲南（ATM）治疗头孢他啶/阿维巴坦耐药肺炎克雷伯菌（CAZ/AVI-R-Kp）引起的血流感染（BSIs），在获得血液培养（BC）结果时无法进行基因分型。
方法：2021年7月20日至8月22日，在我们医院的实验室，无法进行碳青霉烯酶基因分型的分子检测.记录所有革兰氏阴性血流感染，并对患者的特点进行分析。其中,3例患者的CAZ/AVI-R-KpBCs阳性，经验疗法改为M/V加ATM，等待对M/V敏感性的表型测试。随后基于该测试的结果靶向治疗。
结果：KPC和NDM代表了我们多临床中最普遍的碳青霉烯酶。3例CAZ/AVI-R-Kp脓毒症患者接受M/V加ATM治疗，但不知道碳青霉烯酶基因。两个人感染了NDM-Kp，在获得对M/V的灵敏度的结果后，维持联合治疗.第三个人感染了KPC-Kp，因此停用了ATM，在获得报告对M/V完全敏感性的抗菌谱后（MIC=0.25mg/L）。一名NDM-Kp感染患者因基础疾病的并发症而死亡，他住院。
结论：美罗培南/伐巴坦加ATM和随后的降阶梯可能是碳青霉烯酶基因分型无法快速获得的严重CAZ/AVI-R-Kp感染的可能治疗策略。
方法：2021年7月20日至8月22日，在我们医院的实验室，无法进行碳青霉烯酶基因分型的分子检测.记录所有革兰氏阴性血流感染，并对患者的特点进行分析。其中,3例患者的CAZ/AVI-R-KpBCs阳性，经验疗法改为M/V加ATM，等待对M/V敏感性的表型测试。随后基于该测试的结果靶向治疗。
结果：KPC和NDM代表了我们多临床中最普遍的碳青霉烯酶。3例CAZ/AVI-R-Kp脓毒症患者接受M/V加ATM治疗，但不知道碳青霉烯酶基因。两个人感染了NDM-Kp，在获得对M/V的灵敏度的结果后，维持联合治疗.第三个人感染了KPC-Kp，因此停用了ATM，在获得报告对M/V完全敏感性的抗菌谱后（MIC=0.25mg/L）。一名NDM-Kp感染患者因基础疾病的并发症而死亡，他住院。
结论：美罗培南/伐巴坦加ATM和随后的降阶梯可能是碳青霉烯酶基因分型无法快速获得的严重CAZ/AVI-R-Kp感染的可能治疗策略。
