Fàbregas N, Torres A, El-Ebiary M, Ramírez J, Hernández C, González J, de la Bellacasa J P, de Anta J, Rodriguez-Roisin R
Department de Medicina, Universitat de Barcelona, Spain.
Anesthesiology. 1996 Apr;84(4):760-71. doi: 10.1097/00000542-199604000-00002.
The relationship between microbiology and histology in patients with ventilator-associated pneumonia has been sparsely described.
Twenty-five patients who died in the intensive care unit after their lungs had been mechanically ventilated for 72 h were studied. Twenty of the 25 died with clinical suspicion of pulmonary infection. A total of 375 immediate postmortem pulmonary biopsies were obtained after death and processed for quantitative microbiology and histology. Four evolutionary stages of pneumonia were defined: early, intermediate, advanced, and resolution.
At least one specimen with histologic evidence of pneumonia was found in all but two patients (92%). Histologic pneumonia was a widespread and frequent process (46%) of biopsies examined) involving predominantly the lower lobes (55% of all biopsies with pneumonia) and showing different histopathologic stages of progression coexisting in the same lung lobes. Lung cultures were frequently polymicrobial (149 of 375, 40% of the pulmonary biopsy cultures, and 20 of 25, 80% of the cases) and not always yielding the same pathogen (19 microorganisms) when comparing one lung to the other. Histopathology and microbiologic biopsy cultures showed a weak relationship (28% and 49% of species had counts > or = 10(3) cfu/g in samples without pneumonia from patients with and without prior antibiotic treatment, respectively). Histopathologic evolutionary stages were not associated with any differences in quantitative culture results of pulmonary biopsies, independently of prior administration of antibiotics. Higher bacterial concentrations of biopsy cultures were associated with the absence of prior antibiotic treatment.
Ventilator-associated pneumonia is a frequent diffuse and polymicrobial process showing different coexisting degrees of evolution and involving preferentially the lower lobes. Microbiology and histology can be dissociated even in the absence of prior antibiotic treatment. Lung histology appears more reliable than bacteriology as a diagnostic reference test.
机械通气相关性肺炎患者的微生物学与组织学之间的关系鲜有描述。
对25例在重症监护病房机械通气72小时后死亡的患者进行研究。25例中有20例死于临床怀疑肺部感染。死亡后立即获取375份肺组织活检标本，进行定量微生物学和组织学检测。定义了肺炎的四个演变阶段：早期、中期、晚期和消散期。
除2例患者外，其余所有患者（92%）均至少有一份标本存在肺炎组织学证据。组织学肺炎是一种广泛且常见的过程（在所检查的活检标本中占46%），主要累及下叶（所有肺炎活检标本的55%），且在同一肺叶中呈现不同组织病理学进展阶段并存的情况。肺部培养常为多种微生物感染（375份标本中的149份，占肺活检培养的40%，25例病例中的20例，占80%），且双肺比较时并不总是检出相同病原体（19种微生物）。组织病理学与微生物活检培养显示出较弱的相关性（分别接受过和未接受过抗生素治疗的患者，在无肺炎的样本中，28%和49%的菌种计数≥10³cfu/g）。无论是否预先使用抗生素，组织病理学演变阶段与肺活检定量培养结果的差异均无关联。活检培养中细菌浓度较高与未预先使用抗生素有关。
机械通气相关性肺炎是一种常见的弥漫性、多种微生物感染的过程，呈现不同程度的并存演变，且优先累及下叶。即使在未预先使用抗生素治疗的情况下，微生物学与组织学也可能分离。作为诊断参考检测，肺组织学似乎比细菌学更可靠。
