Activity of bacteriocin-like agents from Neisseria meningitidis on strains isolated from patients and carriers.

Strains of Neisseria meningitidis isolated from patients were more often completely insensitive to five bacteriocin-like agents than carrier strains, but no particular bacteriocin type could be associated with patient strains. Two genetically distinct types of insensitivity could be separated by transformation. Insensitivity to four bactericidal agents (from the strains P201, P213, P241 and 99/79) was caused by one common genetic marker whereas insensitivity to a bacteriostatic agent (from the strain 77/79) was caused by another. Insensitivity to the bactericidal agents was more often found among strains belonging to serogroup B than among strains belonging to other groups. But group B strains from patients were more often insensitive than similar strains from carriers. Insensitivity to the bacteriostatic agent seemed evenly distributed among strains of various serogroups. All insensitive patient strains tested showed reduced binding/destruction of inhibitor, indicating that resistance and not tolerance is associated with patient strains.