Abstract：
A major challenge in the treatment of infections has been the rise of extensively drug resistance (XDR) and multidrug resistance (MDR) in Acinetobacter baumannii. The goals of this study were to determine the pattern of antimicrobial susceptibility, blaOXA and carO genes among burn-isolated A. baumannii strains. In this study, 100 A. baumannii strains were isolated from burn patients and their susceptibilities to different antibiotics were determined using disc diffusion testing and broth microdilution. Presence of carO gene and OXA-type carbapenemase genes was tested by PCR and sequencing. SDS-PAGE was done to survey CarO porin and the expression level of carO gene was evaluated by Real-Time PCR. A high rate of resistance to meropenem (98%), imipenem (98%) and doripenem (98%) was detected. All tested A. baumannii strains were susceptible to colistin. The results indicated that 84.9% were XDR and 97.9% of strains were MDR. In addition, all strains bore blaOXA-51 like and blaOXA-23 like and carO genes. Nonetheless, blaOXA-58 like and blaOXA-24 like genes were harbored by 0 percent and 76 percent of strains, respectively. The relative expression levels of the carO gene ranged from 0.06 to 35.01 fold lower than that of carbapenem-susceptible A. baumannii ATCC19606 and SDS - PAGE analysis of the outer membrane protein showed that all 100 isolates produced CarO. The results of current study revealed prevalence of blaOXA genes and changes in carO gene expression in carbapenem resistant A.baumannii.
摘要：
感染治疗的主要挑战是鲍曼不动杆菌的广泛耐药性（XDR）和多药耐药性（MDR）的上升。这项研究的目的是确定抗菌药物敏感性的模式，烧伤分离的鲍曼不动杆菌菌株中的blaOXA和carO基因。在这项研究中,从烧伤患者中分离出100株鲍曼不动杆菌，并使用圆盘扩散测试和肉汤微量稀释确定其对不同抗生素的敏感性。通过PCR和测序检测carO基因和OXA型碳青霉烯酶基因的存在。进行SDS-PAGE以检测CarO孔蛋白，并通过实时PCR评估carO基因的表达水平。对美罗培南的高耐药率（98%），检测到亚胺培南（98％）和多尼培南（98％）。所有测试的鲍曼不动杆菌菌株对黏菌素敏感。结果表明，XDR占84.9%，MDR占97.9%。此外,所有菌株均具有blaOXA-51样和blaOXA-23样和carO基因。尽管如此，blaOXA-58样和blaOXA-24样基因被0%和76%的菌株所携带，分别。carO基因的相对表达水平比碳青霉烯类敏感的鲍曼不动杆菌ATCC19606低0.06至35.01倍，外膜蛋白的SDS-PAGE分析表明，所有100个分离株都产生了CarO。目前的研究结果揭示了blaOXA基因的流行和carO基因表达的变化在碳青霉烯类耐药的鲍曼虫中。
