Garrouste-Orgeas M, Chevret S, Arlet G, Marie O, Rouveau M, Popoff N, Schlemmer B
Département de Réanimation, Hôpital Saint-Louis et Université Paris VII, France.
Am J Respir Crit Care Med. 1997 Nov;156(5):1647-55. doi: 10.1164/ajrccm.156.5.96-04076.
Colonization of the digestive tract has been supposed to be the source of many hospital-acquired infections, especially nosocomial pneumonia. To assess the relationship between oropharyngeal and gastric colonization and subsequent occurrence of nosocomial pneumonia, we prospectively studied 86 ventilated, intensive care unit (ICU) patients. Oropharyngeal or gastric colonizations were detected and quantified on admission and twice weekly during ICU stay. When nosocomial pneumonia was suspected on clinical grounds (new chest X-ray infiltrate and purulent tracheal secretions), diagnosis was assessed on fiberoptic bronchoscopy with quantitative cultures of a protected specimen brush sampling and/or a plugged telescoping catheter sampling yielding > or = 10(3) cfu/ml of at least one microorganism. Bacterial strains responsible for colonization and infection (Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacteriaceae, and Staphylococcus aureus) were compared using pulsed-field electrophoresis. A total of 31 cases (36%) of pneumonia were diagnosed. Oropharyngeal colonization, detected either on admission or from subsequent samples, was a predominant factor of nosocomial pneumonia as compared with gastric colonization. For instance, oropharyngeal colonization with A. baumannii yielded a 7.45-fold estimated increased risk of pneumonia as compared with patients not yet or not identically colonized (p = 0.0004). DNA genomic analysis demonstrated that an identical strain was isolated from oropharyngeal or gastric samples and bronchial samples in all but three cases of pneumonia, due to S. aureus. These findings provide better knowledge of the pathophysiology of nosocomial pneumonia in mechanically ventilated patients.
消化道定植一直被认为是许多医院获得性感染的来源，尤其是医院内肺炎。为了评估口咽部和胃定植与随后发生医院内肺炎之间的关系，我们对86例入住重症监护病房（ICU）并接受机械通气的患者进行了前瞻性研究。在患者入院时以及在ICU住院期间每周两次对口咽部或胃定植进行检测和定量分析。当基于临床症状怀疑发生医院内肺炎（新的胸部X线浸润影和脓性气管分泌物）时，通过纤维支气管镜检查进行诊断，同时对受保护标本刷采样和/或插入式伸缩导管采样进行定量培养，若至少一种微生物的菌落形成单位（cfu）≥10³/ml，则可确诊。使用脉冲场凝胶电泳对引起定植和感染的细菌菌株（鲍曼不动杆菌、铜绿假单胞菌、肠杆菌科细菌和金黄色葡萄球菌）进行比较。共诊断出31例（36%）肺炎病例。与胃定植相比，入院时或后续样本中检测到的口咽部定植是医院内肺炎的主要因素。例如，与尚未定植或未相同定植的患者相比，鲍曼不动杆菌口咽部定植导致肺炎的估计风险增加7.45倍（p = 0.0004）。DNA基因组分析表明，除3例由金黄色葡萄球菌引起的肺炎病例外，在所有肺炎病例中，从口咽部或胃样本以及支气管样本中分离出的是同一菌株。这些发现为机械通气患者医院内肺炎的病理生理学提供了更深入的认识。
