L11 MHD: Gram Positive/Negative Anaerobic Bacteria Flashcards
Which clostridium is responsible for the following:
- Gas gangrene – toxin
- Intra-abdominal infections - vegetative and toxin
- Food poisoning- toxin
Clostridium Perfringens
Structure of C. Perfringens:
- Gram (+ or -)
- Motile?
- Encapsulated?
- forms _____
- ___ Appearance
- Gram +
- Non - motile
- Encapsulated
- SPORES
- Box car appearance
- double zone hemolysis
Gas gangrene by C. Perfringens:
- Requires ____ with devitalized tissue/muscle
- What organism spores germinate quickly?
- TRAUMA with devitalized tissue/muscle
2. Spores of : C. perfringens, C. novyi, C. septicum, C. ramosum germinate quickly
- Extremities, endometrium, abdominal wall
Which type is most common of C. Perfringens that causes gas gangrene?
What are the function of alpha & beta toxins?
Which causes muscle cell necrosis?
Type A most common cause of human disease in U.S
- alpha = lecithinase (phospholipase C) lyses inflammatory cells, RBCs, platelets, & destroys tissue
- abscess does not have any leukocytes since lysed by the organism
= MUSCLE CELL NECROSIS –> ALPHA
Beta toxin:
- Necrotizing enteritis (pig bel)
= food poisoning
What is the first order of therapy of gas gangrene?
What are the systemic symptoms of Gas gangrene?
Clinical presentation?
REMOVE THE DEBRIS
= debridement! (TEST)
(before antibiotics)
Systemic:
- shock
- hyper or hypothermia
- rapid onset
- NECROSIS of muscle
tense edema
bullae formation
gas formation (fermentation)
How does clindamycin affect C. Perfringens?
What antibiotics should be given for C. Perfringens (after debridement)?
- inhibits protein synthesis and decreases toxin production
2. Penicillin, B - lactam inhibitor (Unasyn)
C. Perfringens food poisoning occurs because of what toxin?
How long after ingestion?
- Enterotoxin
- toxin B
- HEAT RESISTANT spores survive (gravy/soup)
- produce an enterotoxin following germination
- 8-24 hours after eating
What is the treatment for C. Perfringens food poisoning?
SELF - LIMITED disease
culture not needed
- Clostridium Tetani enters via
what? Specifically for infants? - Local germination without ____
- What is Tetanospasmin and what does it to?
- puncture wounds, burns
infants = UMBILICUS - No necrosis = no pus or inflammation!
- Tetanospasmin:
- neurotoxin that blocks post-synaptic inhibition of spinal motor reflexes (GABA + glycine)
= SPASMOTIC CONTRACTIONS
- toxin found on plasmid
C. Tetani:
- Gram + or -
- Aerobic or Anaerobic
- How does it appear on gram stain? (shape)
- Gram +
- Anaerobic
- tennis racket shapes
The following describes:
- Gram positive
- SPORE forming
- Obligate anaerobic bacilli
CLOSTRIDIA!
C. Tetani:
GENERALIZED symptoms
- What is the initial symptom of C. Tetani?
- The tone of ____ muscle increases.
- Arm/flexion leg extension is called ____
- The most dangerous clinical symptom of tetanus is what?
- TRISMUS
- lock jaw - Risus Sardonicus = increased tone of Orbicularis Oris
- Opisthotonus
- RESPIRATORY OBSTRUCTION
- spasms of the diaphragm
What is Risus Sardonicus and what anaerobic gram positive bacteria is it associated with?
Associated with ORBICULARIS ORUS
- pulling the corners of the mouth up
C. TETANI
How is tetanus treated? (4)
- Human tetanus immunoglobulin (anti-toxin)
- only effective if haven’t toxins haven’t adhered to tissues - Sedation w/ diazepams
- Supportive (tracheotomy ) to aid with breathing
- BOOSTER
DEBRIDEMENT OF WOUND + PCN
What is the prophylactic treatment of tetanus?
How is it prevented?
- 3 doses of DPT
- revaccinated every 10 years (booster) - PASSIVE IMMUNIZATION
- HTIG for appropriate wound
- hyperimmunoglobulin injected to bind toxin around the site!!!
Clostridium Botulinum:
- Associated with ____ foods
- Entry via ____ from contaminated food
- Avoid giving ____ to infants less than 1years of age.
- HOME CANNING!! (test)
- fruits/vegetables
- fish - PREFORMED TOXIN from contaminated food
- no HONEY to babies less than 1