Carbapenemases play important roles in conferring resistance to beta-lactam antibiotics, including the carbapenems. Detection of carbapenemase activity helps to understand the possible mechanism(s) of carbapenem resistance. Identification of carbapenemases is currently being done by various phenotypic methods and molecular methods. However, innovative biochemical and spectrophotometric methods are desirable as they will be easy to perform, affordable, and rapid. A novel chromogenic method called Carba NP test was introduced recently to screen for carbapenemases in clinical isolates of gram-negative pathogens. We adopted this assay (1) to detect the total carbapenemase activity, (2) to discriminate Class A, B, and D carbapenemases with inhibitors, (3) to compare with carbapenemase genotype, and (4) for direct differential diagnosis of carbapenemases in uncultured clinical sample such as tracheal aspirate. The study included 132 purulent tracheal aspirates. All samples were processed and screened by a protocol optimized in our laboratory, which showed good sensitivity and correlation with genotyping and conventional phenotyping. Our protocol not only offers the fastest way to identify the pathogen but also its carbapenemase profile, directly from uncultured clinical samples in less than 4 hr. Our protocol is currently being validated on other types of clinical specimens in our laboratory.

中文翻译：

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从未培养的气管吸出物中直接检测和鉴别鲍曼不动杆菌的碳青霉烯酶。

碳青霉烯酶在赋予对β-内酰胺抗生素（包括碳青霉烯）的抗性中起重要作用。碳青霉烯酶活性的检测有助于了解碳青霉烯耐药性的可能机制。碳青霉烯酶的鉴定目前正在通过各种表型方法和分子方法进行。然而，创新的生化和分光光度法是理想的，因为它们将易于执行，负担得起并且快速。最近引入了一种新的生色方法，称为Carba NP测试，以筛选革兰氏阴性病原体临床分离物中的碳青霉烯酶。我们采用了这种分析方法（1）检测总碳青霉烯酶活性；（2）区分具有抑制剂的A，B和D类碳青霉烯酶；（3）与碳青霉烯酶基因型进行比较；（4）用于直接鉴别未培养的临床样本（例如气管吸出液）中的碳青霉烯酶。该研究包括132例化脓性气管吸出物。所有样品均通过我们实验室优化的方案进行处理和筛选，显示出良好的敏感性并与基因分型和常规表型相关。我们的协议不仅提供了最快的方法来鉴定病原体，而且还提供了碳青霉烯酶谱图，可在不到4小时的时间内直接从未经培养的临床样品中鉴定出碳青霉烯酶。我们的协议目前正在我们实验室的其他类型的临床标本上得到验证。表现出良好的敏感性，并与基因分型和常规表型相关。我们的协议不仅提供了最快的方法来鉴定病原体，而且还提供了碳青霉烯酶谱图，可在不到4小时的时间内直接从未经培养的临床样品中鉴定出碳青霉烯酶。我们的协议目前正在我们实验室的其他类型的临床标本上得到验证。表现出良好的敏感性，并与基因分型和常规表型相关。我们的协议不仅提供了最快的方法来鉴定病原体，而且还提供了碳青霉烯酶谱图，可在不到4小时的时间内直接从未经培养的临床样品中鉴定出碳青霉烯酶。我们的协议目前正在我们实验室的其他类型的临床标本上得到验证。