Bacteria: Gram-Negative Cocci Flashcards
What is the gram negative cocci
- Neisseria meningitidis
2. Neisseria Gonorrhoeae
Neisseria meningitidis and gonorrhoeae bacteria are
- gram-negative
- diplococci
- oxidase positive
chocolate agar (heated blood agar) is required for growth of
Neisseria meningitidis and gonorrhoeae
the antimicrobials vancomycin, polymyxin (colistin), and nystatin (VPN) are included in
Thayer-Martin agar
Thayer-Martin agar
encourages the growth of Neisseria meningitidis and gonorrhoeae while inhibiting the growth of other microorganisms
Thayer-Martin agar is comprised of
the antimicrobials vancomycin, polymyxin (colistin), and nystatin (VPN), which encourage the growth of Neisseria meningitidis and gonorrhoeae while inhibiting the growth of other microorganisms
Deficiency in the terminal complement components C5-C9 (which form the membrane attack complex (MAC)) results in increased susceptibility to
Neisseria meningitidis and gonorrhoeae infection
The pili of Neisseria meningitidis and gonorrhoeae bacteria display
antigenic variation (due to frequent genetic rearrangement)
The IgA protease of Neisseria meningitidis and gonorrhoeae bacteria
cleaves secretory IgA (found on mucosal surfaces) at the hinge region
Neisseria meningitidis is easily
spread in close quarters, such as college dorms
Important characteristics of Neisseria meningitidis bacteria include:
- gram-negative
- diplococci morphology
- oxidase-positive
- growth on chocolate agar
- growth on Thayer-Martin (VPN) agar
- higher infection rates in patients with C5-C9 complement deficiency (absence of MAC)
- production of an IgA protease, and fimbriae/pili that demonstrate antigenic variation
- encapsulated
Neisseria meningitidis bacteria are able to
ferment both glucose and maltose (in contrast to Neisseria gonorrhoeae, which can only ferment glucose)
Neisseria meningitidis is transmitted via
respiratory droplets (typically from nasopharyngeal colonization of asymptomatic carriers)
Meningococcal vaccines include
antigens contained in the polysaccharide capsule of Neisseria meningitidis (the polysaccharide quadrivalent or conjugate vaccine)
Neisseria meningitidis subtype B causes
⅓ of meningococcal disease in the US because vaccines against subtype B have only recently become available
Sickle cell patients are more susceptible to infections from
encapsulated bacteria, such as Neisseria meningitidis
The outer membrane lipooligosaccharide (LOS) of Neisseria meningitidis causes
sepsis by generating a severe inflammatory response
The inflammatory response caused by the Neisseria meningitidis endotoxins (LOS glycolipids)
The inflammatory response caused by the Neisseria meningitidis endotoxins (LOS glycolipids) → increased capillary permeability
Hemorrhagic skin lesions (e.g. petechiae, purpura) often present in
fulminant meningococcemia
The inflammatory response caused by the Neisseria meningitidis endotoxins (LOS glycolipids)
the inflammatory response caused by the Neisseria meningitidis endotoxins (LOS glycolipids) → increased capillary permeability → hypovolemia → septic shock
Waterhouse-Friderichsen syndrome (also known as fulminant meningococcemia) is a
serious complication of meningococcemia characterized by bilateral adrenal hemorrhage → adrenal insufficiency
_____ is effective against Neisseria meningitidis
ceftriaxone
______ should be administered prophylactically to close contacts of patients with meningococcal infection
rifampin
Important characteristics of Neisseria gonorrhoeae bacteria include:
- gram-negative
- diplococci morphology
- oxidase-positive
- growth on chocolate agar
- growth on Thayer-Martin (VPN) agar
- higher infection rates in patients with C5-C9 complement deficiency (absence of MAC)
- production of an IgA protease, and fimbriae/pili that demonstrate antigenic variation
gonorrhea is a ________ transmitted disease
sexually transmitted disease
Neisseria gonorrhoeae bacteria are
- gram-negative diplococci that are facultatively intracellular within polymorphonuclear leukocytes (often neutrophils)
- non-encapsulated (in contrast to Neisseria meningitidis, which has a polysaccharide capsule)
Neisseria gonorrhoeae infections can progress to
pelvic inflammatory disease in women
A characteristic white, mucopurulent urethral discharge (in both men and women) or vaginal discharge can present in
Neisseria gonorrhoeae infection
Fitz-Hugh Curtis syndrome is
a rare complication of pelvic inflammatory disease (commonly caused by Neisseria gonorrhoeae) characterized by inflammation of the peritoneum and/or diaphragm and the capsule of the liver, leading to the development of adhesions between these structures known as “violin string” adhesions
“Violin string” adhesions
can develop between the peritoneum and/or diaphragm and the capsule of the liver in Fitz-Hugh Curtis syndrome (commonly caused by gonococcal PID)
Disseminated gonococcal infection can cause
septic arthritis or polyarthralgias (typically asymmetrical and of the knee)
Passage of newborns through a birth canal colonized with Neisseria gonorrhoeae can cause
an infection of the conjunctivae (gonococcal ophthalmia neonatorum), which results in blindness if left untreated
Treatment for gonorrhea
ceftriaxone (given as a single intramuscular injection) is effective against gonorrhea
The standard treatment for suspected gonococcal infection
presumes a Neisseria gonorrhoeae and Chlamydia trachomatis co-infection; azithromycin or doxycycline should be administered in addition to ceftriaxone (effective against Chlamydia trachomatis and Neisseria gonorrhoeae, respectively)
