Serum-induced lysis of Pseudomonas aeruginosa

The sensitivity of 12 Pseudomonas aeruginosa strains (5 mucoid and 7 non-mucoid strains) to serum and the interaction of these strains with the complement system was studied. Five strains (4 mucoid and 1 non-mucoid strains) were lysed in 20% normal serum as measured by the release of radiolabelled material from 3H-adenine labelled bacteria. Three of these strains were also lysed in MgEGTA chelated serum. All strains activated complement via the classical pathway, and six strains were able to activate the alternative complement pathway as well. Slime production did not interfere with bacteriolysis and complement consumption.