Metzger Steven, Frobel Rachel A, Dunne W Michael
Accelerate Diagnostics Inc., Tucson, AZ 85714, USA.
Washington University School of Medicine, St Louis, MO 63110, USA.
Diagn Microbiol Infect Dis. 2014 Jun;79(2):160-5. doi: 10.1016/j.diagmicrobio.2013.11.029. Epub 2013 Dec 7.
Diagnosis of ventilator-assisted pneumonia (VAP) requires pathogen quantitation of respiratory samples. Current quantitative culture methods require overnight growth, and pathogen identification requires an additional step. Automated microscopy can perform rapid simultaneous identification and quantitation of live, surface-immobilized bacteria extracted directly from patient specimens using image data collected over 3 h. Automated microscopy was compared to 1 μL loop culture and standard identification methods for Staphylococcus aureus and Pseudomonas spp. in 53 remnant bronchoalveolar lavage specimens. Microscopy identified 9/9 S. aureus and 7/7 P. aeruginosa in all specimens with content above the VAP diagnostic threshold. Concordance for specimens containing targets above the diagnostic threshold was 13/16, with concordance for sub-diagnostic content of 86/90. Results demonstrated that automated microscopy had higher precision than 1 μL loop culture (range 0.55 log versus ≥1 log), with a dynamic range of ~4 logs (10(3) to 10(6) CFU/mL).
呼吸机相关性肺炎（VAP）的诊断需要对呼吸道样本进行病原体定量分析。目前的定量培养方法需要过夜培养，且病原体鉴定还需要额外的步骤。自动显微镜检查可以利用3小时内收集的图像数据，对直接从患者标本中提取的活的、表面固定的细菌进行快速同步鉴定和定量分析。在53份剩余的支气管肺泡灌洗标本中，将自动显微镜检查与1μL环圈培养法以及金黄色葡萄球菌和铜绿假单胞菌的标准鉴定方法进行了比较。显微镜检查在所有病原体含量高于VAP诊断阈值的标本中鉴定出9/9株金黄色葡萄球菌和7/7株铜绿假单胞菌。病原体含量高于诊断阈值的标本的一致性为13/16，低于诊断阈值含量的标本的一致性为86/90。结果表明，自动显微镜检查比1μL环圈培养法具有更高的精确度（范围约为0.55个对数级对≥1个对数级），动态范围约为4个对数级（约10³至10⁶CFU/mL）。
