THREE TYPES OF GROWTH INHIBITION AMONG STRAINS OF NEISSERIA MENINGITIDIS ISOLATED FROM PATIENTS IN NORWAY

Acta Pathologica Microbiologica Scandinavica Series B: Microbio

1984

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Bacteriocin‐like agents from five strains of Neisseria meningitidis were active against other meningococci and some other Neisseria species. Meningococci belonging to the same serogroup or serotype could be subdivided into distinct bacteriocin types. Insensitivity to the inhibitory agents was observed more frequently among serologically groupable strains than among non‐groupable. Strains belonging to serogroup B were more often insensitive to the inhibitors released by four of the donor strains (P201, P213, P241, 99/79) than other groupable strains. Insensitivity to the bacteriocin‐like activity of the fifth donor strain (77/79A) seemed to be evenly distributed among strains of different groups. Strains of serotype 15 were more often insensitive to the five inhibitors than strains belonging to other types. Group B and type 15 are most frequently observed among strains isolated from clinical cases in Norway.

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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INHIBITORY SPECTRUM OF BACTERIOCIN‐LIKE AGENTS FROM NEISSERIA MENINGITIDIS

Jyssum

Acta Pathologica Microbiologica Scandinavica Series B: Microbio

1984

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Bacteriocins (meningocins) in Norwegian isolates of Neisseria meningitidis: possible role in the course of a meningococcal epidemic

Kristiansen²,

Assalkhou³

et al. 2008

APMIS

In the Neisseria meningitidis strain MC58 (serogroup B; ET-5 complex) genome three putative islands of horizontally transferred DNA (IHTs) have been identified. IHT-A2 codes for eight hypothetical proteins and two disrupted open reading frames with similarity to a secretion protein (NMB0097) and an ABC transporter (NMB0098). The strains MC58 and 44/76 (shown here) are meningocin resistant/weakly sensitive. None of these strains are meningocin producers. However, NMB0097 and NMB0098 homologues with open reading frames are found in meningocin producers (N. meningitidis P241 (serogroup A; systemic isolate) and BT878 (serogroup B; carrier isolate), and also in strain FAM18 (serogroup C; ET-37 complex). Knocking out either of the two genes in the strain BT878 yielded mutants that did not secrete meningocin. A similarly disrupted tolC mutant in strain BT878 still released meningocin. Among systemic meningococcal isolates prior to and at the onset (mid-1973 to the end of 1974) of the epidemic peaking in 1975 in North Norway, 12 of 30 (40%) isolates of serogroup A were meningocin producers. However, the rate for serogroup B was 1 of 45 (2.2%). Serogroup B meningocin-resistant/weakly sensitive non-producers dominated in the region from mid-1975 and spread to the rest of the country from then on. No producers were found in selected pharyngeal isolates from healthy carriers collected in Svalbard in the early spring of 1975. Our results suggest that meningocinogeny has played a part in the change from serogroup A to serogroup B among isolates in North Norway during the first half of 1975.

EXPRESSION OF BACTERIOCIN‐LIKE ACTIVITY IN BATCH CULTURES OF NEISSERIA MENINGITIDIS AND CONSEQUENCES FOR GENETIC RECOMBINATION

Jyssum

Acta Pathologica Microbiologica Scandinavica Series B: Microbio

1983

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The bactericidal activity found in four strains of Neisseria meningitidis and the bacteriostatic effect observed in one were expressed in the exponential phase of batch cultures and continued during the stationary phase. The active material was stable for more than 50 hours in agar media. In mixed cultures a strain with inhibitory activity eradicated a sensitive strain, and dominated the culture in the latter part of the exponential phase. Recombination took place in mixed cultures when at least one of the strains had the genetic properties which determine competence in transformation. The presence of inhibitory activity increased the recombination frequency at least ten‐fold. Genetic markers were introduced into a strain with inhibitory activity from sensitive strains of N. meningitidis and from N. cinerea.