Klebsiella spp. are among the most frequently isolated bacteria from burn wounds. These organisms are among the most important opportunistic pathogens, causing hospital-acquired and healthcare-associated infections worldwide. Limited information is available about prevalence of AmpC-producing Klebsiella pneumoniae from burn patients. Therefore, the aim of this study was to determine the characterization of AmpC beta-lactamase among K. pneumoniae isolated from burn patients. Samples were collected from wound specimens of patients with burn injury from a burn hospital in Tehran during 18 months (March 2015 to August 2016). For phenotypic detection of AmpC beta-lactamase, disk diffusion method with cefoxitin was used for screening, AmpC disk test and boronic acid inhibitor-based method were used as confirmatory tests. Polymerase chain reaction (PCR) was performed to screen all isolates with AmpC genes including ACCM, DHAM, EBCM, FOXM, MOXM, and CITM. Finally, PCR products were validated using sequencing. During this study, 102 isolates of K. pneumoniae were collected. Among these isolates, 52.9% suspected as AmpC producer by disk agar diffusion cefoxitin screening method. By confirmatory phenotypic methods, 19.6% of isolates considered as AmpC producer. Molecular analysis revealed 43.1% of cefoxitin-resistant isolates harbored at least one of the AmpC genes including CITM (22.5%), EBCM (21.5%), DHAM (7.8%), and FOXM (0.98%). In addition, 5.8% of isolates harbored two AmpC genes and 2.9% harbored three AmpC genes. In conclusion, K. pneumoniae is becoming a serious problem in burn patients. Accurate and precise methods and guidelines should be designed for detection of antibiotic-resistant mechanisms. Our data showed the high rate of AmpC beta-lactamase among K. pneumoniae isolated from burn patients, which limit the treatment options. Therefore, the results of this study can provide evidence to help for appropriate treatment of burn patients.

中文翻译：

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从烧伤患者中分离出的肺炎克雷伯菌中AmpCβ-内酰胺酶基因共存的首次报道。

克雷伯菌属。是烧伤伤口中最常见的细菌之一。这些生物是最重要的机会性病原体之一，导致全球范围内医院获得和医疗保健相关的感染。关于烧伤患者产生AmpC的肺炎克雷伯菌的流行情况的信息有限。因此，本研究的目的是确定从烧伤患者中分离出的肺炎克雷伯菌中AmpCβ-内酰胺酶的特性。在18个月内（2015年3月至2016年8月）从德黑兰一家烧伤医院的烧伤患者的伤口标本中收集样品。对于AmpCβ-内酰胺酶的表型检测，采用头孢西丁的纸片扩散法进行筛查，使用AmpC纸片试验和基于硼酸抑制剂的方法进行确证试验。进行聚合酶链反应（PCR）来筛选具有AmpC基因的所有分离株，包括ACCM，DHAM，EBCM，FOXM，MOXM和CITM。最后，使用测序验证了PCR产物。在这项研究中，收集了102株肺炎克雷伯菌。在这些分离物中，通过盘琼脂扩散头孢西丁筛选方法怀疑有52.9％是AmpC生产者。通过确证的表型方法，将19.6％的分离株视为AmpC产生者。分子分析显示43.1％的耐头孢西丁的分离株具有至少一个AmpC基因，包括CITM（22.5％），EBCM（21.5％），DHAM（7.8％）和FOXM（0.98％）。此外，5.8％的分离株带有两个AmpC基因，而2.9％的分离株带有三个AmpC基因。总之，肺炎克雷伯菌正在成为烧伤患者的严重问题。应设计出准确，准确的方法和指南以检测抗生素耐药机制。我们的数据显示，从烧伤患者中分离出的肺炎克雷伯菌中AmpCβ-内酰胺酶的发生率很高，这限制了治疗选择。因此，这项研究的结果可以提供证据，以帮助适当治疗烧伤患者。