Neisseria and Moraxella Flashcards
Lecture 8
What are characteristics of Neisseria?
many species isolated from humans; N. gonorrhoeae (always pathogen) and N. meningitidis (commensal) are primary human pathogens of genus
Where is Neisseria found?
often in humans, in the upper respiratory tract of carriers, also a part of microbiome of mucous membranes in urogenital tracts
What do N. gonorrhoeae and N. meningitidis have in common?
both gram-negative diplococci (shaped like kidney beans with flat side together); have pili that aid in attaching to human cells; refer increased CO2 for growth; optimal growth at 35-37 C in moist environment; fastidious (sensitive to drying and temp and survive poorly in environment); non-motile, and affinity for mucous membranes due to presence of pili
What are the differences between N. gonorrhoeae and N. meningitidis?
N. gonorrhoeae - isolated from cervix, urethra, rectum, and pharynx; can be found in CSF, joints and skin; transmitted by sexual contact; causes local inflammation; “gonococcus” or “GC”; rarely lethal; killed rapidly in bloodstream; very fastidious, not encapsulated; humans are only reservoir
N. meningitidis - isolated from nasopharynx, CSF, blood; normal nasopharyngeal flora; transmitted by contact with respiratory secretions or airborne droplets; causes systemic infection; “meningococcus”; life threatening; multiplies rapidly in blood stream; not fastidious; capsules present; nasopharynx of humans is common reservoir
N. meningitidis carbohydrate test
Glucose: +
Maltose: +
Lactose: -
Sucrose: -
N. lactamica carbohydrate test
Glucose: +
Maltose: +
Lactose: +
Sucrose: -
N. gonorrhoeae carbohydrate test
Glucose: +
Maltose: -
Lactose: -
Sucrose: -
N. sicca carbohydrate test
Glucose: +
Maltose: +
Lactose: -
Sucrose: +
Moraxella catarrhalis carbohydrate test
Glucose: -
Maltose: -
Lactose: -
Sucrose: -
What is gonorrhea?
related to flow of semen; sexually transmitted disease that is an acute pyogenic infection of epithelium of mucosal surfaces; effects endocervix in women and urethra in men
What other diseases can N. gonorrhoeae cause?
pharyngitis, suppurative arthritis, ophthalmitis (newborns in vaginal births), pelvic inflammatory disease (untreated cases and causes sterility and ectopic pregnancies
How can we test for N. gonorrhoeae?
take specimen from infected area and immediately place into transport media or plate; urine places into transport media (NAAT); swab from infected area (as per exudate) and then test in nucleic acid amplification test (NAAT), grow in culture, or gram-stain test
What should we be aware of when sending a culture of potential N. gonorrhoeae to the lab?
the organisms are very sensitive to atmosphere and temperature; specimen should be sent to lab immediately; the plate needs to be put in commercial zipper; CO2 generating system and sent to lab
How can we identify Neisseria?
1) select for with MTM agar
2) oxidase positive
3) rapid tests
4) biochemicals
Epidemiology of N. gonorrhoeae
occurs mostly among young people aged 15-24
How do we treat gonorrhea?
ceftriaxone with azithromycin is treatment of choice; many strains are resistant to penicillin
How does Neisseria meningitidis transmit?
nasopharynx of humans is the only reservoir, spread by respiratory droplets; 5-15% of teens and young adults are carriers; 90% rates in closed populations such as frat, military barracks, or within families
What does N. meningitidis cause?
meningitis usually seen in children and young adults, causes a fever, headache, neck stiffness, photophobia, irritability; meningococcemia that comes with petechial rash and can lead to shock and disseminated intravascular coagulation (DIC)
How do we test for N. meningitidis?
take a specimen of CSF or blood and then culture it or use molecular detection
Epidemiology of meningitidis
we get <1,00 cases a year in the US; most frequent cause of meningitis in infants, children, and adolescents
What vaccine do we have for N. meningitidis?
there are multiple serogroups that cause disease, the most common are B, C, Y and W135; can have vaccines for A, C, Y, W135 (quadrivalent vaccine) and B
How do we treat N. meningitidis?
use 3rd generation cephalosporin, penicillin, chloramphenicol; or give rifampin to close contacts for prevention
What are the characteristics of Moraxella catarrhalis?
gram-negative diplococci; normal microbiome of upper respiratory tract; is not fastidious; grows well on lab media
What disease is caused by Moraxella catarrhalis?
otitis media, sinusitis; in immunocompromised and elderly we see pneumonia and bronchitis
How do we identify Moraxella catarrhalis?
we take eduate from infected area and culture it; similar identification to Neisseria
How do we treat M. catarrhalis?
most isolates are resistant to penicillin; susceptible to most antibiotics; decongestants are key
