Singkham-In Uthaibhorn, Chatsuwan Tanittha
Interdisciplinary Program of Medical Microbiology, Graduate School, Chulalongkorn University, Bangkok, Thailand.
Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Diagn Microbiol Infect Dis. 2018 Jun;91(2):169-174. doi: 10.1016/j.diagmicrobio.2018.01.008. Epub 2018 Jan 31.
Carbapenem-resistant Acinetobacter baumannii clinical isolates (n=23) were investigated for carbapenem resistance mechanisms and in vitro activities of carbapenems in combination with amikacin, colistin, or fosfomycin. Major carbapenem resistance mechanism was OXA-23 production. The vast majority of these isolates were OXA-23-producing A. baumannii ST195 and ST542, followed by novel STs, ST1417, and ST1423. The interuption of carO by a novel insertion sequence, ISAba40, was found in two isolates. The combinations of imipenem and fosfomycin, meropenem and amikacin, imipenem and amikacin, and imipenem and colistin were synergistic against carbapenem-resistant A. baumannii by 65.2%, 46.2%, 30.8%, and 17.4%, respectively. Surprisingly, the combination of imipenem and fosfomycin was the most effective in this study against A. baumannii, which is intrinsically resistant to fosfomycin. Imipenem and fosfomycin inhibit cell wall synthesis; therefore, fosfomycin may be an adjuvant and enhance the inhibition of cell wall synthesis of carbapenem-resistant A. baumannii when combined with imipenem.
对23株耐碳青霉烯类鲍曼不动杆菌临床分离株进行了碳青霉烯类耐药机制以及碳青霉烯类与阿米卡星、黏菌素或磷霉素联合的体外活性研究。主要的碳青霉烯类耐药机制是产生OXA-23。这些分离株绝大多数是产生OXA-23的鲍曼不动杆菌ST195和ST542，其次是新的序列类型ST1417和ST1423。在两株分离株中发现了一种新的插入序列ISAba40对carO的中断。亚胺培南与磷霉素、美罗培南与阿米卡星、亚胺培南与阿米卡星以及亚胺培南与黏菌素的联合用药分别对耐碳青霉烯类鲍曼不动杆菌有65.2%、46.2%、30.8%和17.4%的协同作用。令人惊讶的是，在本研究中亚胺培南与磷霉素的联合用药对鲍曼不动杆菌最有效，而鲍曼不动杆菌对磷霉素具有内在耐药性。亚胺培南和磷霉素抑制细胞壁合成；因此，磷霉素可能是一种佐剂，与亚胺培南联合使用时可增强对耐碳青霉烯类鲍曼不动杆菌细胞壁合成的抑制作用。
