Johanson W G, Stephen J J, Pierce A K
J Clin Invest. 1974 May;53(5):1320-5. doi: 10.1172/JCI107679.
Lung clearance of Diplococcus pneumoniae was markedly reduced in rats with acute hemorrhagic pulmonary edema produced by instillation of hydrochloric acid. Bacterial clearance was enhanced in both control and acid-instilled animals by pretreatment with a bacteriostatic antibiotic, tetracycline, 30 mg/kg. From these data the contributions of bacterial multiplication and bacterial elimination to net lung bacterial clearance were estimated. In control animals the constant for exponential bacterial elimination was -1.4283 (fractional clearance = 76% per h), and the doubling time for the pneumococcus was 170 min. In acid-instilled rats the elimination constant was -0.5336 (fractional clearance = 41% per h), and the doubling time of the pneumococcus was 47 min, approximating the doubling time of 42 min observed with pneumococci grown in broth. These results indicate that, in the case of pneumococci, both bacterial elimination and bacterial growth contribute to lung bacterial clearance in normal animals as well as animals with damaged lungs. In the present study changes in both parameters were required to explain the observed results in acid-instilled animals. The pulmonary pathogenicity of some bacterial species may be determined by their capacity for growth in the lung, since infection of the lung occurs when bacterial multiplication exceeds the rate of elimination of viable organisms.
通过滴注盐酸产生急性出血性肺水肿的大鼠，其肺炎双球菌的肺清除率显著降低。用30mg/kg的抑菌抗生素四环素预处理后，对照动物和滴注酸的动物的细菌清除率均得到提高。根据这些数据，估计了细菌繁殖和细菌清除对肺细菌净清除率的贡献。在对照动物中，指数细菌清除常数为-1.4283（每小时清除率为76%），肺炎球菌的倍增时间为170分钟。在滴注酸的大鼠中，清除常数为-0.5336（每小时清除率为41%），肺炎球菌的倍增时间为47分钟，接近在肉汤中生长的肺炎球菌观察到的42分钟的倍增时间。这些结果表明，对于肺炎球菌，细菌清除和细菌生长在正常动物以及肺受损动物的肺细菌清除中都起作用。在本研究中，需要两个参数的变化来解释滴注酸动物中观察到结果。某些细菌种类的肺致病性可能由它们在肺中生长的能力决定，因为当细菌繁殖超过活生物体的清除率时，肺部就会发生感染。
