Development and Evaluation of Novel Applied Diagnostic Platforms for Clinical Microbiology

传统的微生物工作是缓慢的，有时不准确，依赖于表型培养鉴定，然后进行抗菌药物敏感性测试。基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）和实时分子检测（抗菌素耐药基因微阵列）等新技术提高了临床微生物实验室的诊断能力，并为研究和开发创造了一个令人兴奋的领域。鉴于这些平台产生的深入和高度准确（有时复杂）的结果，需要进行仔细的详细分析，以更好地了解所鉴定微生物的临床意义和检测到的耐药机制。 在本财政年度，我们进行了一项多中心合作研究，以调查解没食子链球菌亚种的作用。本研究旨在检测造血干细胞移植（HSCT）受者中巴氏杆菌的感染情况，并评估两种不同MALDI-TOF MS系统在亚种水平上鉴定微生物的性能。我们还研究了一种新的实时PCR检测方法的性能，用于直接从原始标本中检测四种主要的碳青霉烯酶基因，同时进行选择性培养。从监测标本中准确检测超广谱β-内酰胺酶（ESBLs）和万古霉素耐药肠球菌（VREs）的方法也正在进行评估，以使患者免于不必要和昂贵的感染控制预防措施，并提高微生物学实验室的诊断特异性。最后，正在评估从培养物中检测β-内酰胺酶的快速表型方法，并开发从原始标本中检测这些酶的新方法。

Traditional microbiological work up is slow and sometimes inaccurate, relying on phenotypic culture identification followed by antimicrobial susceptibility testing. Newer technologies, such as matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and real-time molecular detection (antimicrobial resistance genes microarrays) have advanced the diagnostic capabilities of clinical microbiology laboratories and have created an exciting field for research and development. Given the in-depth and highly accurate (sometimes complex) results that are produced by such platforms, careful detailed analyses are required to better understand the clinical significance of the organisms identified and the resistance mechanisms detected. During this fiscal year, we have undertaken a multi-center collaborative study to investigate the role of Streptococcus gallolyticus subsp. pasteurianus in hematopoietic stem cell transplant (HSCT) recipients and to evaluate the performance of two different MALDI-TOF MS systems for the identification of microorganisms to the subspecies level. We are also investigating the performance of a novel real-time PCR assay for the detection of four major carbapenmase genes direct from primary specimens, in parallel with selective culture. Methods to accurately detect extended spectrum beta-lactamases (ESBLs) and vancomycin resistant Enterococci (VREs) from surveillance specimens are also being evaluated in an effort to remove patients from unnecessary and costly infection control precautions, as well as improving the diagnostic specificity for microbiology laboratories. Finally, evaluation of rapid phenotypic methods to detect beta-lactamases from culture and the development of new approaches to detect these enzymes from primary specimens is underway.