Experimental pulmonary infection of mice by tracheal intubation of Pseudomonas aeruginosa: the use of antineoplastic agents to overcome natural resistance

Tracheal intubation of viable Pseudomonas aeruginosa ATCC 19660 into the lungs of mice had no significant effect on the animals even with administration of organisms as high as 5.0 x 10⁹ CFU. Animals treated with a single injection of an antineoplastic drug were, however, susceptible to bacterial challenge into the lungs. LD₅₀ values of 4.1 x 10⁷, 4.8 x 10⁷, and 1.0 x 10⁸ CFU were obtained when animals were simultaneously infected and treated with methotrexate, vincristine sulfate, or cytosine arabinoside, respectively.