Chapter 8: Neisseria Flashcards
Neisseria
Only pathogenic gram-negative cocci
Pairs = diplococci
What does Neisseria meningitidis cause?
Meningitis
Life-threatening sepsis (meningococcemia)
What are the virulence factors of the meningococcus?
Capsule: A, B, C
Endotoxin (LPS)
IgA1 protease: Exclusive to Neisseria, cleaves IgA in half
and Pili : attachment
What does Endotoxin LPS from meningococcus cause?
Blood vessel destruction (hemorrhage) and sepsis
Petechiae
Can damage adrenal glands
What are the high risk groups for infection by Neisseria meningitidis (meningococcus)
Infants aged 6 months to 2 years
Army recruits
College freshmen
How does Neisseria meningitidis spread?
via respiratory secretions and usually lives asymptomatically in the nasopharynx
What is the major clue to for invasive meningococcal infection?
petechial rash
What is Meningococcemia
Intravascular infection of Neisseria meningitidis
Abrupt onset of spiking fevers, chills, arthralgia (joint pains) and muscle pains, and petechial rash
What is Fulminant meningococcemia?
It is the waterhouse-friederichsen syndrome
Septic shock
Bilateral hemorrhage into the adrenal glands ->adrenal insufficiency
Hypotension and tachycardia abruptly occurs
Rapily enlarging petechial skin lesions
DIC, coma
What is the most common form of meningococcal disease?
Meningitis: striking infants less than a year of age
Fever, vomiting, irritability and/or lethargy
Bulging open anterior fontanelle
Slightly older infants may develop stiff neck and positive Kernig’s and Brudzinski’s signs
What does Neisseria gonorrhoeae/gonococcus cause?
The SECOND most common sexually transmitted disease, gonorrhea
What are the Virulence factors of gonococcus?
Pili, outer membrane protein porins
Opa proteins
What virulence factor of gonococcus protects the bacteria from our Abs, vaccines, and also serves to prevent phagocytosis?
Pili
Hypervariable amino acid sequences
Pili also possibly hold the bacteria so close to host cells that Mo or neurtrophils are unable to attack
What is the role of outer membrane protein porins of gonoccucus?
PorA and PorB appear to promote invasion into epithelial cells
What are opa proteins?
class of outer membrane proteins that promote adherence and invasion into epithelial cells; expression results in opaque colonies
What do pili, porins and opa proteins allow gonoccoci to do overall?
bind to fallopian tube non-ciliated eipthelial cells where LPS can destroy cells
Gonococcal disease in men
Organisms penetrates the mucous membranes of the urethra, causing inflammation (urethritis), dysuria, and purulent discharge from the penis. Both symptomatic and asymptomatic men pass the disease
Epididymitis, prostatitis, and urethral strictures
MSM: rectal gonococcal infection
What are the symptoms of Gonococcal disease in men?
Painful urination along with a purulent urethral discharge (pus expressed from tip of penis)
Gonococcal disease in women
More likely to be asymptomatic with minimal urethral discharge
Infects columnar epithelium of the cervix - reddened, friable, purulent exudate
Both symptomatic and asymptomatic women can transmit the disease
What are the symptoms of Gonococcal disease in women?
If symptoms do develop, the women may complain of lower abdominal discomfort pain with sexual intercourse
Purulent vaginal discharge
What can gonococcal infection of the cervix progress to?
PID - pelvic inflammatory disease
Infection of the uterus (endometritis), fallopian tubes (salpinitis), and/or ovaries (oophoritis)
Low fever, lower abdominal pain, abnormal menstrual bleeding, cervical m otion tenderness
Menstruation allows bacteria to spread
What can increase the risk of cervical gonococcal infection progressing to PID?
IUD
What is the major cause of PID?
Chlamydia trachomatis
What are the complications of PID?
Sterility: scarring
Ectopic pregnancy: salpingitis and scaring
Abscesses: in fallopian tubes, ovaries, or peritoneum
Peritonitis: infected peritoneal fluid
Peri-hepatitis: capsule around liver
