Unusual antineisserial activity expressed by a systemic isolate of Neisseria meningitidis. antimeningococcal effect and properties

Abstract

Antineisserial activity expressed by the systemic Neisseria meningitidis strain 77/79A was studied using the cross-streaking technique. Of 271 meningococcal isolates tested, > 84% were sensitive to this strain. The degree of susceptibility was largely dependent upon the agent characteristics of the individual isolates. Serogroup A sulfonamide-resistant systemic strains and non-groupable sulfonamide-sensitive isolates from healthy carriers were highly sensitive to the antagonistic activity. Among insensitive or weakly sensitive strains, serogroup B sulfonamide-resistant isolates dominated. The activity is of general interest as it also antagonized growth of bacteriocin producers. Colonization by the producer strain might determine the agent characteristics of a surviving population. Group B was predominant among disease-causing strains in Norway at the time when strain 77/79A was isolated. A component was purified by ammonium sulfate precipitation, gel filtration and hydrophobic interaction chromatography. It was bacteriostatic and partly resistant to proteolysis by trypsin. Preparations remained active after 30 min at 90 degrees C, but activity was lost after 20 min at 120 degrees C. Nevertheless, sodium dodecyl sulfate-polyacrylamide gel electrophoresis produced a band by Coomassie Brilliant Blue staining, corresponding to a molecular mass of approximately 52 kDa. Further characterization was limited due to the low levels of active substance produced.