Flashcards in Lecture 7 Deck (48):
Diseases of Gram negative Neisseria
Neisseria Meningitides and Neisseria Gonorrhea
What type of agar does Neisseria need?
chocolate agar (heated blood agar)
What is the shape of Neisseria Meningitides?
kidney shape arranged in pairs with wide polysaccharide capsule, strict aerobe
Does Neisseria Meningitides contain plasmids?
no plasmids since no exotoxin production
How is meningitides transmitted?
airborn droplets- colonize mucous membrane of nasopharynx and URT
Where is meningitides common?
crowded places, military camps and student camps
virulence factors of meningitides
1. polysaccharide capsule which resists phagocytosis, endotoxin present in cell wall responsible for septic shock and septicemia, and organism produces IgA protease, which helps to attach to mucous membrane
What does meningitides cause and describe it
meningitis- fever, headache, nuchal rigidity, disorientation, turbid CSF, leukocytes, organisms inside neutrophils
What causes septic shock and describe it
bacteremia- fever, shock, widespread purpura and disseminated intravascular clotting
What is the physically demonstrable symptoms of meningitis
Brudzinski's sign- severe neck stiffness causes a patients hips and knees flex when neck is flexed
define Kernig's sign
Severe stiffness of the hamstrings causes inability to straighten the leg when the hip is flexed to 90 degrees
Where do you do a lumbar puncture?
3rd or 4th lumbar spine
What does hemorrhage in adrenal cortex lead to?
adrenal insufficiency known as waterhouse=friedrichen syndrome
2 organisms causing meningitis in children
Pneumo and meningo cocci
Treatment for meningitis
penicillin G, sulphonamides are also effective
Prevention for meningitis
chemoprophylaxis- rifampicin & ciprofloxin , vaccine available- meningo coccal vaccine contains capsular polysaccharides
Who is Nis gonorrhoeae symptomatic in?
men and asymptomatic in women
Where is Ni Gonorrhoeae found?
in genital tract- less commonly in anaorectal region and oropharynx
Examples of virulence factors
pili, cell wall lip oligosachride and IgA protease
where does genetic variation occur
in pili and outer membrane proteins as a result of chromosomal rearrangement
clinical manifestations of Nis. Gonorrhoeae in men
causes urethritis, painful urination and pus in urine-- gonorrhea- disseminated infection lead to septic arthritis in sexually active men
repeated infections of the urethra can lead to what?
urethral stricture-- occluding of the urethra
define reiters syndrome
non gonococcal urethritis, arthritis and conjunctivitis which is immunological
clinical manifestations of Nis. Gonorrhea in women
mostly asymptomatic- in few it can cause purulent vaginal discharge and inner menstrual bleeding- lead to PID, ectopic pregnancy, salphingitis
Can fetuses contract nis. gonorrhoeae?
yes- when passing through the birth canal- severe purulent bilateral conjunctivitis can occur- other STDs can co-exist
Treatment for Nis. Gonorrhoeae
Penicillin G is drug of choice- nowadays ceftrioxone is given
Prevention of Nis. Gonorrhoeae
use of a condom- there is no vaccine- babies can be given erythromycin drops for eyes
List the 4 organisms in the Gram + Category
Bacillus, Clostridium, Corney bacterium diphtheriae and lysteriae momcytogens
Which gram + groups are spore forming?
Bacillus and Clostridium
Which gram + groups are non-spore forming?
Corney bacterium diptheriae and lysteriae
What are the two species of Bacillus and is it aerobic or anaerobic?
aerobic- species are B anthrax and B cereus
What are the four species of Clostridium and is it aerobic or anaerobic?
anaerobic- Cl tetani, Cl botulinum, Cl perfingens, Cl difficile
Describe B Anthrax
large rods with square ends with spores in the center- arranged in chains (Bamboo stick appearance) - non motile
What is the capsule of B anthrax?
Capsule is D glutamate- antigenic and antiphagocytic
Anthrax is mainly a disease of_____
herbivorous animals (cattle, goat, horse) - humans get the disease accidentally
three forms humans can get B Anthrax
skin, lungs, gastro intestinal track
Transmission of B Anthrax
spores found in soil- remain for years- can get from wound infection. Inhale, ingest of contaminated meat, inhalation
What is wool sorter's disease?
inhalation of B Anthrax from hides, skin, wool and bristles
What is malignant pustule and how do you get it?
Painless ulcer with black crust on the skinw ith surrounding edema- caused by skin exposure to B Anthrax
Define pulmonary anthrax of B Anthrax
initially flu like symptoms, dry cough, retro sternal pressure, septic shock and death
How do you diagnose Pulmonary Anthrax disease?
Xray shows widening of the mediastinum and pleural effusion
Results of GI track B Anthrax
vomiting, abdominal pain, bloody diarrhea
What does the lab diagnosis of B Anthrax look like?
2-3 grayish colonies: medusa head appearance on blood agar, in gelatin medium you will see inverted fir tree appearance, and smears show characteristic chains (bamboo sticks-blue)
What is used to treat B Anthrax?
Penicillin G is treatment of choice
What can be used to prevent B Anthrax?
Ciprofloxacin, Doxycycline- animals dyin of anthrax disease should be burnt not buried , vaccine is available
Describe B Cereus
a soil dwelling organism which causes food poisoning- spores found on food grains survive steaming and frying
2 types of enterotoxins produced by B Cereus
1. Causes ADP ribosylation of G protein resulting in non-bloody diarrhea like cholera 2. acts as super Ag causes vomiting and nausea