Segal R, Pogoreliuk I, Dan M, Baumoehl Y, Leibovitz A
Shmuel Harofeh, Geriatric Medical Centre, Beer-Yaakov, Israel.
J Hosp Infect. 2006 May;63(1):79-83. doi: 10.1016/j.jhin.2005.11.005. Epub 2006 Mar 3.
Aspiration of oropharyngeal contents is a constant threat for elderly patients fed via a nasogastric tube (NGT). Colonization of the oropharynx of these patients by pathological flora and the development of biofilms on the feeding tube has been documented recently. In addition, the presence of the NGT may interfere with the gastro-oesophageal sphincter, leading to gastro-oesophageal reflux. Thus, the passage of pathogenic bacteria in both directions is facilitated. The purpose of this study was to explore the microbiota of the gastric juice and the oropharynx in NGT-fed elderly patients. Samples of gastric juice were drawn after an overnight fast, and microbial cultures and direct pH measurement were performed. Concomitant cultures were obtained from the oropharynx. Overall, 107 gastric and oropharyngeal cultures were obtained from 52 subjects. Pathogenic flora (Gram-negative bacteria or Staphylococcus aureus) were isolated from 74% of stomach samples and from 69% of oropharynx samples. Proteus spp. (26%) and Escherichia coli (22%) were the most common isolates in the gastric juice, and Proteus spp. (24%) and Pseudomonas spp. (21%) were the most common isolates in the oropharynx. Similarity in the composition of the oropharynx and gastric flora was observed in most cases. The gastric pH was relatively high (4.57 +/- 0.65 at 3 h after feeding and 4.2 +/- 0.9 at 12 h after feeding) and was highly correlated with the isolation of pathogenic bacteria (r = 0.58, P < 0.01). These results support the view that in addition to the oropharynx, the stomach of NGT-fed elderly patients constitutes a reservoir of pathogens that could be associated with the risk of aspiration pneumonia. The cause of the high gastric pH and its relation to pathogenic bacteria warrants further study.
对于通过鼻胃管（NGT）进食的老年患者来说，误吸口咽内容物是持续存在的威胁。近期有文献记载，这些患者的口咽部会被致病性菌群定植，且饲管上会形成生物膜。此外，鼻胃管的存在可能会干扰胃食管括约肌，导致胃食管反流。因此，病原菌在两个方向上的传播都更为容易。本研究的目的是探究通过鼻胃管进食的老年患者胃液和口咽部的微生物群。禁食一夜后抽取胃液样本，并进行微生物培养和直接pH测量。同时从口咽部获取培养样本。总体而言，从52名受试者身上获取了107份胃和口咽部培养样本。在74%的胃样本和69%的口咽部样本中分离出了致病菌群（革兰氏阴性菌或金黄色葡萄球菌）。变形杆菌属（26%）和大肠杆菌（22%）是胃液中最常见的分离菌，变形杆菌属（24%）和假单胞菌属（21%）是口咽部最常见的分离菌。在大多数情况下，观察到口咽部和胃内菌群组成具有相似性。胃内pH相对较高（进食后3小时为4.57±0.65，进食后12小时为4.2±0.9），且与病原菌的分离高度相关（r = 0.58，P < 0.01）。这些结果支持了这样一种观点，即除了口咽部外，通过鼻胃管进食的老年患者的胃也是病原菌的储存库，这可能与误吸性肺炎的风险相关。胃内pH升高的原因及其与病原菌的关系值得进一步研究。
