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Category: Clinical Microbiology
Neisseria, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555817381/9781555817381.ch34-1.gif /docserver/preview/fulltext/10.1128/9781555817381/9781555817381.ch34-2.gifAbstract:
The genus Neisseria currently consists of 28 species, most of which are commensals of mucous membranes of humans and animals. The two species most commonly associated with disease are Neisseria meningitidis and N. gonorrhoeae. N. meningitidis, also termed meningococcus, is spread by large-droplet oropharyngeal secretions and rarely causes invasive meningococcal disease (IMD), in the form of meningitis and sepsis. On the other hand, N. gonorrhoeae, which is also named gonococcus, is spread by sexual contact and is the causal agent of gonorrhea. In many industrialized countries the incidences of IMD and gonorrhea have decreased over the last decades, with present rates of around 1/100,000 and over 30/100,000, respectively. Microscopic examination of samples remains a cornerstone of laboratory diagnosis, as specificities of detection of Gram-negative diplococci from cerebrospinal fluid and genital swabs are high for the confirmation of meningococcal meningitis and gonorrhea, respectively. Both species are exquisitely susceptible to extreme temperatures and desiccation, necessitating rapid transport of specimens to the laboratory for culture-based detection. Culture remains the standard approach for verifying the presence of Neisseria spp. in human specimens and is the only method allowing antibiotic resistance testing. Nevertheless, molecular assays, notably nucleic acid amplification tests, are frequently employed for the diagnosis of IMD and gonorrhea, due to less stringent sampling requirements. Moreover, DNA sequence-based single- and multilocus approaches, as well as matrix-assisted laser desorption ionization–time of flight mass spectrometry, are gaining acceptance as methods for species assignment within the genus Neisseria.
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Gram stain of CSF from a patient with meningococcal meningitis. doi:10.1128/9781555817381.ch34.f1
Gram stain of CSF from a patient with meningococcal meningitis. doi:10.1128/9781555817381.ch34.f1
Colony morphology (left) and Gram stain (right) of N. bacilliformis ( 10 ). The strain was isolated from a human periodontal pocket. It was characterized by nearly complete sequencing of the 16S rRNA gene. The species is noteworthy due to its rod-like morphology. doi:10.1128/9781555817381.ch34.f2
Colony morphology (left) and Gram stain (right) of N. bacilliformis ( 10 ). The strain was isolated from a human periodontal pocket. It was characterized by nearly complete sequencing of the 16S rRNA gene. The species is noteworthy due to its rod-like morphology. doi:10.1128/9781555817381.ch34.f2
Commercially available NAATs for detection of N. gonorrhoeae
Commercially available NAATs for detection of N. gonorrhoeae
Characteristics of medically relevant Neisseria species a
Characteristics of medically relevant Neisseria species a
Molecular typing methods for N. meningitidis
Molecular typing methods for N. meningitidis