Noguchi Taro, Matsumura Yasufumi, Yamamoto Masaki, Nagao Miki, Takakura Shunji, Ichiyama Satoshi
Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.
BMC Infect Dis. 2017 Jan 7;17(1):44. doi: 10.1186/s12879-016-2150-6.
Cefotaxime plays an important role in the treatment of patients with bacteremia due to Enterobacteriaceae, although cefotaxime resistance is reported to be increasing in association with extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase (AmpC).
We conducted a case-control study in a Japanese university hospital between 2011 and 2012. We assessed the risk factors and clinical outcomes of bacteremia due to cefotaxime-non-susceptible Enterobacteriaceae (CTXNS-En) and analyzed the resistance mechanisms.
Of 316 patients with Enterobacteriaceae bacteremia, 37 patients with bacteremia caused by CTXNS-En were matched to 74 patients who had bacteremia caused by cefotaxime-susceptible Enterobacteriaceae (CTXS-En). The most common CTXNS-En was Escherichia coli (43%), followed by Enterobacter spp. (24%) and Klebsiella spp. (22%). Independent risk factors for CTXNS-En bacteremia included previous infection or colonization of CTXNS-En, cardiac disease, the presence of intravascular catheter and prior surgery within 30 days. Patients with CTXNS-En bacteremia were less likely to receive appropriate empirical therapy and to achieve a complete response at 72 h than patients with CTXS-En bacteremia. Mortality was comparable between CTXNS-En and CTXS-En patients (5 vs. 3%). CTXNS-En isolates exhibited multidrug resistance but remained highly susceptible to amikacin and meropenem. CTX-M-type ESBLs accounted for 76% of the β-lactamase genes responsible for CTXNS E. coli and Klebsiella spp. isolates, followed by plasmid-mediated AmpC (12%). Chromosomal AmpC was responsible for 89% of CTXNS Enterobacter spp. isolates.
CTXNS-En isolates harboring ESBL and AmpC caused delays in appropriate therapy among bacteremic patients. Risk factors and antibiograms may improve the selection of appropriate therapy for CTXNS-En bacteremia. Prevalent mechanisms of resistance in CTXNS-En were ESBL and chromosomal AmpC.
头孢噻肟在治疗肠杆菌科细菌所致菌血症患者中发挥着重要作用，尽管据报道，与超广谱β-内酰胺酶（ESBL）和AmpCβ-内酰胺酶（AmpC）相关的头孢噻肟耐药性正在增加。
我们于2011年至2012年在一家日本大学医院进行了一项病例对照研究。我们评估了头孢噻肟不敏感肠杆菌科细菌（CTXNS-En）所致菌血症的危险因素和临床结局，并分析了耐药机制。
在316例肠杆菌科细菌菌血症患者中，37例由CTXNS-En引起菌血症的患者与74例由头孢噻肟敏感肠杆菌科细菌（CTXS-En）引起菌血症的患者进行了匹配。最常见的CTXNS-En是大肠埃希菌（43%），其次是肠杆菌属（24%）和克雷伯菌属（22%）。CTXNS-En菌血症的独立危险因素包括既往CTXNS-En感染或定植、心脏病、血管内导管的存在以及30天内的既往手术。与CTXS-En菌血症患者相比，CTXNS-En菌血症患者接受适当经验性治疗和在72小时时实现完全缓解的可能性较小。CTXNS-En和CTXS-En患者的死亡率相当（5%对3%）。CTXNS-En分离株表现出多重耐药性，但对阿米卡星和美罗培南仍高度敏感。CTX-M型ESBLs占负责CTXNS大肠埃希菌和克雷伯菌属分离株的β-内酰胺酶基因的76%，其次是质粒介导的AmpC（12%）。染色体AmpC负责89%的CTXNS肠杆菌属分离株。
携带ESBL和AmpC的CTXNS-En分离株导致菌血症患者适当治疗的延迟。危险因素和抗菌谱可能有助于改善CTXNS-En菌血症适当治疗的选择。CTXNS-En中常见的耐药机制是ESBL和染色体AmpC。
