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Neisseria species and their complicated relationships with human health

Neisseria spp. have multiple modes of interfacing with the human host. N. gonorrhoeae is considered to be a true pathogen as it elicits an inflammatory response upon urethral infection of the human male and causes a delayed inflammatory response, pelvic inflammatory disease, in women. Interestingly, although classified as a pathogen it can asymptomatically colonise the oral mucosa and anorectal sites that self-resolve over 4–12 months. N. meningitidis, the causative agent of invasive meningococcal disease (IMD), is considered an opportunistic pathogen. Whereas N. gonorrhoeae is highly clona, N. meningitidis has diversified into at least 11 clonal complexes that are highly associated with the…

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 Neisseria

Most Neisseria species are commensal, meaning they usually do not cause disease in healthy individuals, although some can act as opportunistic pathogens in those who are immunocompromised. Treatment for infections caused by these bacteria often involves antibiotics, with ongoing challenges due to rising antibiotic resistance, particularly in N. gonorrhoeae. Vaccines have been developed against some strains of N. meningitidis, although no effective vaccine currently exists for N. gonorrhoeae. Understanding the biology and pathogenicity of Neisseria is crucial for public health, especially in regions where these infections are prevalent.

 Understanding Neisseria: The Bacteria Behind Meningitis and Gonorrhea Understanding Neisseria: The Bacteria Behind Meningitis and Gonorrhea

Neisseria it is a large genus of bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogen: N. meningitides- major cause of meningitis and N. gonorrhoeae- cause of gonorrhea. Are closely related, 70% DNA homology mostly Differentiated by a few laboratory tests and specific characteristics. Most importantly differentiated by clinical presentations of the diseases they cause: Meningococci typically are found in the URT and cause meningitis and Gonococci cause genital infections.

Articles of Interest

Atypical, Yet Not Infrequent, Infections with Neisseria Species

Neisseria species are extremely well-adapted to their mammalian hosts and they display unique phenotypes that account for their ability to thrive within niche-specific conditions. The closely related species N. gonorrhoeae and N. meningitidis are the only two species of the genus recognized as strict human pathogens, causing the sexually transmitted disease gonorrhea and meningitis and sepsis, respectively. Gonococci colonize the mucosal epithelium of the male urethra and female endo/ectocervix, whereas meningococci colonize the mucosal epithelium of the human nasopharynx. The pathophysiological host responses to gonococcal and meningococcal infection are distinct. However, medical evidence dating back to the early 1900s demonstrates that these two species can cross-colonize anatomical niches, with patients often presenting with clinically-indistinguishable infections.

Beyond the usual suspects: Reviewing infections caused by typically-commensal Neisseria species

Although rare, incidences of atypical Neisseria infection have been reported in the literature since at least 1944. As with certain species of other genera such as Klebsiella42 and Haemophilus, which are usually commensal but exhibit opportunistic pathogenesis, commensal Neisseria infection is known to occur mostly within immunocompromised or immunosuppressed patients. The use of Eculizumab, for example, a widely used complement inhibitor, is a risk factor for Neisseria infection.

Characteristics of Neisseria Species Colonized in the Human’s Nasopharynx

Large genus of commensal bacteria that colonize the mucosal surfaces of many animals. Of the 11 species that colonize humans, only two are pathogens. N. meningitidis and N. gonorrhoeae often cause symptomatic infections, a commensal-like behavior.

Etymologia: Neisseria

A gram-negative, non-motile diplococcal bacterium, Neisseria (Figure) is named after Albert Ludwig Sigesmund Neisser, a German physician who discovered Neisseria gonorrhoeae in 1879.

Neisseria: Recent advances and future challenges

Neisseria gonorrhoeae and Neisseria meningitidis are major causes of morbidity and mortality worldwide. Advances in 'omics technologies and in vitro and in vivo infection models are revealing important new insights into the biology and pathogenesis of these Neisseria species, and the biology of commensal Neisseria that colonize the nasopharynx of humans and other animals.

The Biology of Neisseria Adhesins

Members of the genus Neisseria include pathogens causing important human diseases such as meningitis, septicaemia, gonorrhoea and pelvic inflammatory disease syndrome. Neisseriae are found on the exposed epithelia of the upper respiratory tract and the urogenital tract. Colonisation of these exposed epithelia is dependent on a repertoire of diverse bacterial molecules, extending not only from the surface of the bacteria but also found within the outer membrane. During invasive disease, pathogenic Neisseriae also interact with immune effector cells, vascular endothelia and the meninges.

The Genetics of Neisseria Species

Neisseria gonorrhoeae and Neisseria meningitidis are closely related organisms that cause the sexually transmitted infection gonorrhea and serious bacterial meningitis and septicemia, respectively. Both species possess multiple mechanisms to alter the expression of surface-exposed proteins through the processes of phase and antigenic variation. This potential for wide variability in surface-exposed structures allows the organisms to always have subpopulations of divergent antigenic types to avoid immune surveillance and to contribute to functional variation.

The genetics of Neisseria species

Neisseria gonorrhoeae and Neisseria meningitidis are closely related organisms that cause the sexually transmitted infection gonorrhea and serious bacterial meningitis and septicemia, respectively. Both species possess multiple mechanisms to alter the expression of surface-exposed proteins through the processes of phase and antigenic variation.

Resources

Neisseria.org

Neisseria.org exists to provide an electronic resource for all individuals interested in research and clinical aspects of the Neisseria, especially Neisseria meningitidis and Neisseria gonorrhoeae

MLST

Neisseria – a stain of gram-negative coccoid bacteria. The stain got its name in honor of the German dermatovenerologist and bacteriologist Albert Ludwig Sigesmund Neisser (1855-1916). He discovered the causative agent of gonorrhea (1879). Neisseria includes pathogenic for humans species of the Neisseria: the causative agent of gonorrhea (Neisseria gonorrhoeae) and the causative agent of meningitis (Neisseria meningitidis). Traditionally, Neisseria gonorrhoeae is often called gonococcus, Neisseria meningitidis is called meningococcus. Also, non-pathogenic types of Neisseria bacteria living on mucous membranes (Neisseria sicca, Neisseria mucosa, Neisseria perflava) are found in humans. Under the microscope, Neisseria looks like coffee beans.

Taylor & Francis

Neisseria refers to a genus of microorganisms that can be both pathogens and normal flora in humans. The genus includes two human pathogens, Neisseria gonorrhoeae (gonococcus) and Neisseria meningitidis (meningococcus), and individuals with an increased susceptibility to disseminated infections by Neisseria microorganisms such as N. meningitidis and N. gonorrhoeae.