L7 MHD: Gram + Rods Flashcards
What are the key characteristics of Bacillus?
- Spore forming?
- Gram negative or Positive?
- Shape?
- Aerobic or anaerobic?
- Motility?
- Spore forming gram positive rod that is widespread in nature
- Prefers aerobic conditions
- Motile except for B. anthracis
Bacillus anthracis is a ___________ biothreat agent. What disease does it cause?
What are three ways to get this disease? (three I’s)
-Category A biothreat agent that causes Anthrax
Disease is caused by:
- Inoculation- 95%- contaminated soil or infected animal products
- Ingestion
- Inhalation- Wool Sorter’s Disease, processing goat hair, biological weapons (damn terrorists)
_________________ are organisms/biological agents that pose highest risk to national security and public health beacause they can be easily disseminated or transmitted from person to person, result in high mortality rates and have potential for major health impact, might cause public panic and social disruption, and require special action for public health preparedness.
Category A Pathogens
Describe cutaneous anthrax infection in humans.
- ___________ papule
- ___________ surrounded by vesicles
- ___________ Eschar
- _______% mortality
Painless papule, ulcer surrounded by vesicles, necrotic eschar, 20% mortality
GI Anthrax
- Where does upper GI anthrax present? Lower GI?
- What are the symptoms of lower GI anthrax infection?
- What is the mortality rate?
- Upper GI anthrax infection: ulcers in the mouth & espophagus
- Lower GI: terminal ileum most commonly affected, nausea/vomiting, malaise, bloody diarrhea
- 100% mortality
Inhalation Anthrax
- What are the initial symptoms?
- What happens in the second stage?
- What disease is a rare consequence of inhalation anthrax? What symptoms occur in 50% of patients?
- What occurs within 3 days unless treatment is initiated immediately?
There is a prolonged latent period (2 months or more) and the initial symptoms are non-specific
-Fever, SOB, cough, HA, vomiting, chills, chest & abdominal pain
Second stage: rapid worsening fever, edema, and enlargement of mediastinal lymph nodes (responsible for the widened mediastinum observed on chest X-Ray)
- Pulmonary disease is rare, meningeal symptoms occur in 50% of patients
- Shock & death occurs within 3 days unless treatment is initiated immediately
Widened mediastinum is observed on a chest X- ray. What do you suspect is the causative agent?
Inhalation anthrax
How do the following contribute to anthrax’s pathogenesis?
- Capsule?
- Edema toxin?
- Lethal toxin?
- Protective AG?
- Capsule: inhibits phagocytosis of replicating cells
- Edema toxin: fluid accumulation
- Lethal toxin: stimulates macrophages to release tumor necrosis factor and IL-1Beta
- Protective AG: binds specific cell surface receptors that enable ET & LT to enter the cell
Following a gram stain, that showed gram + box car shaped bacilli, you get the results of a biochemical test that are as follows:
- Motility- negative
- Non-hemolytic
- PCN susceptible
- What bacterium do you suspect?
Anthrax
What 4 sites can you get culture from for anthrax diagnosis?
Skin, blood, sputum, CSF
What is the preferred treatment for anthrax? What do you use when anthrax is of possible terrorist origin because of manipulated resistance?
-How long does prophylaxis for inhaled anthrax occur?
Preferred treatment: PCN
- Use ciprofloxacin or doxycycline if you suspect manipulated PCN resistance
- Prophylaxis for inhalation- 60 days
What are 4 ways of getting a Bacillus Cereus infection? How is it diagnosed?
4 ways of getting bacillus cerrus are:
- food poisoning (caused by exotoxins- there’s an emetic and diarrheal form)
- ocular infections
- central line infections (contaminated lines must be removed)
- opportunistic infections
-Bacillus cereus is diagnosed with a culture from the eye, wound, or implicated food product
Key Characteristics of Listeria Spore forming? Gram positive or negative? Shape? Habitat?
- Non-spore forming gram-positive rod
- Habitat: animals, environment, refrigerated foods
This bacteria is found in soil, stream water, and sewage. It’s part of the fecal flora of many animals. Plants, meats and dairy can be contaminated via the water or animal feces and patients may get sick due to consumption of undercooked and unpasteurized foods. There’s a small % of asymptomatic human fecal carriage. This describes the epidemiology of what bacteria?
Listeria Monocytogenes
What bacteria can infect patients from “ready to eat” foods and smoked seafoods? What other foods can be contaminated?
Listeria Monocytogenes
-Soft cheese, veggies, and cold cuts at the deli counter can also be infected
