[Bacteriological studies on pharyngeal and tracheal colonization in patients of operations and patients in ICU]

Bacterial colonization of the pharynx before and one week after operation, and contamination of the trachea during intubation in 7 patients who underwent operations were investigated. And bacterial colonization of pharynx, tracheas, and mechanical-ventilators in 7 ICU patients was investigated. Flora of palms of 10 ICU personnel was also examined: 1) Oral bacteria began to be found in the trachea several hours after intubation. 2) In oropharyngeal flora, one week after operation, Neisseria and anaerobes which belong to normal flora decreased because of antibiotics, but no new resistant bacteria appeared. 3) Although isolates from pharynx of preoperative patients were normal flora, those of ICU patients were Staphylococcus epidermidis, Enterococcus spp., gram-negative rods such as Pseudomonas aeruginosa, and yeast liked organisms etc, which were resistant to antibiotics. 4) From the trachea of intubated patients in ICU, oral bacteria were isolated. 5) Pseudomonas pickettii was isolated from the expiratory side of ventilator circuits in one patient, but it was not isolated from the patient. 6) From hands of ICU personnel, gram-positive bacteria such as coagulase negative staphylococci, Coryne bacterium spp. and Bacillus spp. were isolated. 7) One patient in ICU, who developed pneumonia due to resistant Bacteroides fragilis following oropharyngeal colonization, was reported. These studies suggested the importance of environmental control, careful selection of antibiotics, and attention to change of flora.