呼吸器感染症における上気道常在細菌叢の役割に関する経気管吸引法による研究 Studies of Role of Normal Upper Airway Flora in Lower Respiratory Tract Infection by Transtracheal Aspiration

呼吸器感染症と上気道常在細菌との関係を明らかにする目的で, 呼吸器感染症の患老58例に経気管吸引法 (以下TTA) を74回施行し, その吸引物と同時喀出疾について細菌の検索を行ない比較検討した.TTAで細菌が検出されたのは40例54回であった.TTAと喀出疾では検出菌が一致しない例があり, 慢性下気道感染症では23%において検出菌が全く一致しなかった.検出された細菌の種類はTTA19種に対し, 喀出疾23種で大差はなかった.TTAでは54%に複数で細菌が検出された.細菌の出現頻度は, TTAではH. influenzaeが48%, 次いでS. pneumoniaeが33%と多かったが, B. catarrhalisとH. parainfluenzaeも15%に検出した.喀出疾ではN. nonpathogen 70%, α-streptcoccus 65%と多かったが, H. influenzae 24%. S. pneumoniae 28%と少なかった.慢性下気道感染症におけるTTAでは, 上述の細菌を90%に認め, 同一細菌がくり返し検出される例も多かった.<BR>以上の成績より, 呼吸器感染症では単独ないし, 複数の上気道常在細菌が容易に下気道に侵入すること, さらに慢性下気道感染症では侵入した細菌が下気道に定着し, 固有細菌叢を形成することが推測された.呼吸器感染症, 中でも慢性下気道感染症は "常在細菌感染症" が主体をなしていると考える.

We studied by trastracheal aspiration (TTA) the relationship between lower respiratory tract infections and normal upper airway flora. This was done by comparing the organisms obtained by TTA with these in the sputum in 58 patients with lower respiratory tract infection. In some patients, the organisms obtained by TTA were not identical with those in the sputum. In 23% of cases with chronic lower airway infection, organisms by TTA were not identical in the organisms in the sputum. We identified altogether 19 species of organisms in TTA and 23 species in sputum. By TTA, We identified 2 or more organisms in 54% cases<BR>Organisms identified as follows; H. influenzae (48%), S. pneumoniae (38%), B. catarrhalis (15%) and H. parainfluenzae (15%) by TTA and a-streptococcus (65%), nonpathogenic Nisseria (70%), H. influenzae (24%) and S. pneumoniae (28%) in sputum.<BR>In 90% of the cases with chronic lower airway infections, we identified the above organisms by TTA and in some cases we repeatedly cultured the same organisms, from the same patients.<BR>From the results we realize that the organisms of upper airway flora go through readily into lower airway. Particularly, by chronic infections of lower airway, invaders seem to be settled at the location of lower part, and produce bacterial colonies. Thus, in the chronic infectious diseases of the lower airway, the organisms that live always in upper airway could play an important role on it.