Neisseria
Neisseria | |||
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Gram-stain
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Scientific classification | |||
Domain: | Bacteria | ||
Phylum: | Pseudomonadota | ||
Class: | Betaproteobacteria | ||
Order: | Neisseriales | ||
Family: | Neisseriaceae | ||
Genus: | Neisseria Trevisan, 1885 | ||
Species | |||
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Neisseria is a large genus of
Neisseria species are
Pathogenesis and classification
Pathogens
Species of this genus (family Neisseriaceae) of parasitic bacteria grow in pairs and occasionally fours, and thrive best at 98.6 °F (37 °C) in the animal body or serum media.
The genus includes:
- gonococcus) causes gonorrhea.
- septicaemia.
The immune system's
Neisseria bacteria have also been shown to be an important factor in the early stages of canine plaque development.[2]
Nonpathogens
This genus also contains several, believed to be commensal, or nonpathogenic, species:
- Neisseria bacilliformis
- Neisseria cinerea
- Neisseria elongata
- Neisseria flavescens
- Neisseria lactamica
- Neisseria macacae
- Neisseria mucosa
- Neisseria oralis
- Neisseria polysaccharea
- Neisseria sicca
- Neisseria subflava
- Neisseria flava
However, some of these can be associated with disease.[4][5]
Biochemical identification
All the medically significant species of Neisseria are positive for both catalase and oxidase. Different Neisseria species can be identified by the sets of sugars from which they will produce acid. For example, N. gonorrhoeae makes acid from only glucose, but N. meningitidis produces acid from both glucose and maltose.
Polysaccharide capsule. N. meningitidis has a
Unlike most other Gram-negative bacteria, which possess
History
The
Genomes
The genomes of at least 10 Neisseria species have been completely sequenced.[3] The best-studied species are N. meningitidis with more than 70 strains and N. gonorrhoeae with at least 10 strains completely sequenced. Other complete genomes are available for N. elongata, N. lactamica,[8] and N. weaveri. Whole genome shotgun sequences are available for hundreds of other species and strains.[9] N. meningitidis encodes 2,440 to 2,854 proteins while N. gonorrhoeae encodes from 2,603 to 2,871 proteins. N. weaveri (strain NCTC 13585) has the smallest known genome with only 2,060 encoded proteins[10] although N. meningitidis MC58 has been reported to have only 2049 genes.[3] The genomes are generally quite similar. For example, when the genome of N. gonorrhoeae (strain FA1090) is compared to that of N. meningitidis (strain H44/76) 68% of their genes are shared.[9]
Genome properties of Neisseria sp.[3] | ||
---|---|---|
species | Size (bp) | gene number |
N. elongata | 2,260,105 | 2589 |
N. sicca | 2,786,309 | 2842 |
N. mucosa | 2,542,952 | 2594 |
N. subflava | 2,288,219 | 2303 |
N. flavescens | 2,199,447 | 2240 |
N. cinerea | 1,876,338 | 2050 |
N. polysaccharea | 2,043,594 | 2268 |
N. lactamica 23970 | 2,148,211 | 2359 |
N. gonorrhoeae FA1090 | 2,153,922 | 2002 |
N. meningitidis MC58 | 2,184,406 | 2049 |
Vaccine
Diseases caused by
Antibiotic resistance
The acquisition of cephalosporin resistance in N. gonorrhoeae, particularly ceftriaxone resistance, has greatly complicated the treatment of gonorrhea, with the gonococcus now being classified as a "superbug".[13]
Genetic transformation
Genetic transformation is the process by which a recipient bacterial cell takes up DNA from a neighboring cell and integrates this DNA into the recipient’s genome by recombination. In N. meningitidis and N. gonorrhoeae, DNA transformation requires the presence of short DNA sequences (9-10 monomers residing in coding regions) of the donor DNA. These sequences are called DNA uptake sequences (DUSs). Specific recognition of DUSs is mediated by a type IV pilin.[14] Davidsen et al.[15] reported that in N. meningitidis and N. gonorrhoeae, DUSs occur at a significantly higher density in genes involved in DNA repair and recombination (as well as in restriction-modification and replication) than in other annotated gene groups. These authors proposed that the over-representation of DUS in DNA repair and recombination genes may reflect the benefit of maintaining the integrity of the DNA repair and recombination machinery by preferentially taking up genome maintenance genes that could replace their damaged counterparts in the recipient cell. Caugant and Maiden noted that the distribution of DUS is consistent with recombination being primarily a mechanism for genome repair that can occasionally result in generation of diversity, which even more occasionally, is adaptive.[16] It was also suggested by Michod et al.[17] that an important benefit of transformation in N. gonorrhoeae is recombinational repair of oxidative DNA damages caused by oxidative attack by the host’s phagocytic cells.
International Pathogenic Neisseria Conference
The International Pathogenic Neisseria Conference (IPNC), occurring every two years, is a forum for the presentation of cutting-edge research on all aspects of the genus Neisseria. This includes immunology, vaccinology, and physiology and metabolism of N. meningitidis, N. gonorrhoeae and the commensal species. The first IPNC took place in 1978, and the most recent one was in September 2016. Normally, the location of the conference switches between North America and Europe, but it took place in Australia for the first time in 2006, where the venue was located in Cairns.[18]
References
- ISBN 978-0-8385-8529-0.
- ^ Early Canine Plaque Biofilms: Characterization of Key Bacterial Interactions Involved in Initial Colonization of Enamel. Lucy J. Holcombe, Niran Patel, Alison Colyer, Oliver Deusch, Ciaran O’Flynn, Stephen Harris. PLOS One, 2014.
- ^ PMID 20676376.
- PMID 11422256.
- PMID 22798652.
- ISBN 978-1-904455-45-5.
- ISBN 978-1-55581-940-8.
- PMID 25291770.
- ^ a b "Neisseria in the PATRIC database". PATRIC. 2017-02-26. Retrieved 2017-02-26.
- PMID 27563039.
- ^ "meningococcal group B vaccine". Medscape. WebMD. Retrieved December 16, 2015.
- ISBN 978-1-904455-51-6.
- PMID 23231489.
- PMID 23386723.
- PMID 14960717.
- PMID 19464092.
- PMID 18295550.
- ^ "IPNC - Neisseria.org". neisseria.org. Retrieved 2021-01-02.