Neisseria Flashcards
a 14-year-old girl who was sent home from school because she had a fever of 38°C, a severe headache, neck stiffness, and was falling asleep in class. When her fever rose to 40°C, her mother took her to the emergency room, where a blood pressure of 60/20 and several petechial hemorrhages were found. Gram-negative diplococci were seen in a Gram stain of the spinal fluid.
• What is the causative agent?
Neisseria
a 14-year-old girl who was sent home from school because she had a fever of 38°C, a severe headache, neck stiffness, and was falling asleep in class. When her fever rose to 40°C, her mother took her to the emergency room, where a blood pressure of 60/20 and several petechial hemorrhages were found. Gram-negative diplococci were seen in a Gram stain of the spinal fluid.
• What is the diagnosis?
Meningitdis
a 14-year-old girl who was sent home from school because she had a fever of 38°C, a severe headache, neck stiffness, and was falling asleep in class. When her fever rose to 40°C, her mother took her to the emergency room, where a blood pressure of 60/20 and several petechial hemorrhages were found. Gram-negative diplococci were seen in a Gram stain of the spinal fluid.
What is the most likely virulence factor to cause the fever,
hypotension, and petechial hemorrhages?
Endotoxin , only with gram negative cocci
a 14-year-old girl who was sent home from school because she had a fever of 38°C, a severe headache, neck stiffness, and was falling asleep in class. When her fever rose to 40°C, her mother took her to the emergency room, where a blood pressure of 60/20 and several petechial hemorrhages were found. Gram-negative diplococci were seen in a Gram stain of the spinal fluid.
What is the best diagnostic test?
CSF
a 14-year-old girl who was sent home from school because she had a fever of 38°C, a severe headache, neck stiffness, and was falling asleep in class. When her fever rose to 40°C, her mother took her to the emergency room, where a blood pressure of 60/20 and several petechial hemorrhages were found. Gram-negative diplococci were seen in a Gram stain of the spinal fluid.
tratment ?
Penicillin G
Neisseria are
gram-negative cocci that resemble paired kidney beans.
Oxiditive test result of neisseria
Positive
Species of neisseria ?
Neisseria meningitidis
Neisseria gonorrhoeae
Portal of entery for N. Meningitdis ?
Droplet from respiratory tract
Portal of entery for N. gonorrhoeae
Genital tract
Presence of polysaccharides capsule for Neisseria meningitidis
Positive
Presence of polysaccharides capsule for Neisseria gonorrhoeae
Negative
Result of maltose fermentation of Neisseria meningitidis?
Positive
Results of maltose fermintaion Neisseria gonorrhoeae?
Negative
Most common cause of meningitis in between the ages of 2 and 18
years
Neisseria meninigitdis
more than 80% of cases of bacterial meningitis in infants older than 2
months of age:
Streptococcal pneumonia, and neisseria meningitdis
Role of polysaccharide capsule:
Antiphagocytic action
Five serotypes of polysaccharides cpasule cause most cases of meningitis and meningococcemia:
A,B,C,Y,W
A virulance factor that causes fever, shock, and other pathophysiologic
changes. ?
Endotoxin
A virulance factor that helps the bacteria attach to
the membranes of the upper respiratory tract by cleaving secretory
IgA.
IgA protase
Virulance factor that act as an inhibitor of complement factor C3b
Factor H binding protein (FHBP)
Virulance factor that resist phagocytosis by
polymorphonuclear leukocytes (PMNs).
Polysaccharides capsule
The severe form of
meningococcemia: the life-
threatening
With high fever, shock,
widespread purpura,
disseminated intravascular
coagulation, thrombocytopenia,
and adrenal insufficiency
Waterhouse–Friderichsen
syndrome:
Lab diagnosis of neisseria
smear and culture of blood and spinal fluid samples: gram-negative
cocci
Rapid detection, detects capsular
polysaccharide in the spinal fluid
Latex agglutination test:
treatment of choice for meningococcal infections.
Penicillin G
the most common source of the organism neisseria gonorrhoeae
Genital tract infection
but anorectal and pharyngeal infections are important sources as well
Neisseria gonorrhoeae
Has no polysaccharide capsule, instead: it has ?
Pillus protein
mediate attachment to mucosal cell surfaces
and are antiphagocytic
Pili
Endotoxin virulance factor of neisseria gonorrhoeae?
lipooligosaccharide contain lipid A
Pili, Outer membrane proteins , IgA protease, endotoxin
Are considered
A virulance factor of neisseria gonorrhoeae
Septic arthritis in sexually active adults.
Is commonly caused by
Disseminated gonococcal infections (DGI)
Disseminated gonococcal infections (DGI) are difficult to diagnose using laboratory because
Organisim is not cultured in 50% of the cases
Culture of neisseria gonorrhoeae
Thayer-Martin medium, which is a chocolate agar
containing antibiotics (vancomycin, colistin, trimethoprim, and
nystatin) to suppress the normal flora
Diagnosis test detect the
presence of gonococcal nucleic acids in patient specimens.
Nucleic acid amplification test
treatment of choice in uncomplicated gonococcal
infections
Ceftriaxone
Mixed infection with gonorrhoeae are treated by
trachomatis are common,
azithromycin or doxycyclin
