PDF(Pubmed)
Abstract：
Acinetobacter baumannii is a non-fermentative Gram-negative bacterium that can cause nosocomial infections in critically ill patients. Carbapenem-resistant A. baumannii (CRAB) has spread rapidly in clinical settings and has become a key concern. The main objective of this study was to identify the distribution of integrons and biofilm-formation-related virulence genes in CRAB isolates. A total of 269 A. baumannii isolates (219 isolates of CRAB and 50 isolates of carbapenem-sensitive A. baumannii (CSAB)) were collected. Carbapenemase genes (bla KPC, bla VIM, bla IMP, bla NDM, and bla OXA-23-like) and biofilm-formation-related virulence genes (abal, bfms, bap, and cusE) were screened with PCR. Class 1 integron was screened with PCR, and common promoters and gene cassette arrays were determined with restriction pattern analysis combined with primer walking sequencing. Whole-genome sequencing was conducted, and data were analyzed for a bla OXA-23-like-negative isolate. All 219 CRAB isolates were negative for bla KPC, bla VIM, bla IMP, and bla NDM, while bla OXA-23-like was detected in 218 isolates. The detection rates for abal, bfms, bap, and cusE in 219 CRAB were 93.15%, 63.93%, 88.13%, and 77.63%, respectively. Class 1 integron was detected in 75 CRAB (34.25%) and in 3 CSAB. The single gene cassette array aacA4-catB8-aadA1 with relatively strong PcH2 promoter was detected in class 1 integrons. The bla OXA-23-like-negative CRAB isolate was revealed to be a new sequence type (Oxford 3272, Pasteur 2520) carrying bla OXA-72, bla OXA-259, and bla ADC-26. In conclusion, bla OXA-23-like was the main reason for CRAB\'s resistance to carbapenems. A new (Oxford 3272, Pasteur 2520) CRAB sequence type carrying the bla OXA-72, bla OXA-259, and bla ADC-26 was reported.
摘要：
鲍曼不动杆菌是一种非发酵革兰阴性菌,可引起危重病患者医院感染。耐碳青霉烯类鲍曼不动杆菌（CRAB）在临床上迅速传播，并已成为一个关键问题。这项研究的主要目的是确定CRAB分离株中整合子和生物膜形成相关毒力基因的分布。总共收集了269个鲍曼不动杆菌分离株(219个CRAB分离株和50个碳青霉烯敏感鲍曼不动杆菌(CSAB)分离株)。碳青霉烯酶基因(blaKPC，BlaVIM,blaIMP,blaNDM,和blaOXA-23样）和生物膜形成相关的毒力基因（abal，bfms,bap,和cusE)用PCR筛选。用PCR筛选1类整合子，和常见的启动子和基因盒阵列通过限制性模式分析结合引物步行测序确定。进行了全基因组测序，并分析了BlaOXA-23样阴性分离株的数据。所有219个CRAB分离株均为blaKPC阴性，BlaVIM,blaIMP,和BLANDM,而在218个分离株中检测到blaOXA-23样。abal的检出率，bfms,bap,219名CRAB中的cusE为93.15%，63.93%,88.13%,和77.63%，分别。在75个CRAB（34.25％）和3个CSAB中检测到1类整合子。在1类整合子中检测到具有相对强的PcH2启动子的单基因盒阵列aacA4-catB8-aadA1。发现blaOXA-23样阴性CRAB分离株是携带blaOXA-72，blaOXA-259和blaADC-26的新序列类型（牛津3272，巴斯德2520）。总之,BLAOXA-23样是CRAB对碳青霉烯类耐药的主要原因。据报道，一种新的（牛津3272，巴斯德2520）CRAB序列类型携带blaOXA-72，blaOXA-259和blaADC-26。
