Bug parade part 3 Flashcards
What is the difference between category A and category B bioterror and catery Cagents, according to CDC ranking?
Category A: can be easily disseminated or transmitted from person to person, result in high mortality rates, have potential to cause panic and social breakdown, and require special action.
Category B agents, on the other hand, are only moderately easy to disseminate and result in moderate or low mortality rates.
cutaneous anthrax:
how do you get it? what happens?
how: contact with infected tissues of animal or contaminated hair/wool/etc. spores germinate and vegetative cells grow. gelatinous edema progresses to a papule progresses to a necrotic ulcer. mortality occurs in 20% of cases, usually with septicemia
gastrointestinal anthrax: how do you get it? what happens?
results from ingestion of contaminated uncooked meat. Highly lethal. mucosal lesion spreads to lymphatics and blood.
pulmonary anthrax.
inhalation of spores and lung infection leads to pulmonary anthrax. rapid onset with high fever and chest pain. prgresses to systemic hemorrhage and has a 60% case fatality rate.
what drugs can be used to treat anthrax?
penicillin, doxycycline, and ciprofloxacin
What are important virulence factors for B. anthracis?
capsular polypeptide with D glutamic acid that interferes with phagocytosis and anthrax toxins
Francisella tularensis: gram, characteristics, motility, growth, oxygen,
encapsulated pale gram-negative rod. grows on chocolate agar and is a facultative intracellular bacterium, lipid rich capsule, strict aerobe, non-motile
F. tularensis: what disease does it cause? What forms cause the disease? How is it transmitted? reservoir? Prevention?
disease: tularemia
caused by type a and type b strains, but type a more virulent (less than 10 bacteria can cause disease)
transmitted by rabbits and deer flies, or contact with infected animals or ingestion of contamiated food or water, or inhalation of aerosolized organisms.
reservoir: rodents and rabbits
prevention: yes, vaccine is possible: LVS vaccine for at risk personnel
What are the main clinical manifestation of tularemia? What are the five types? and incubation time?
acute, febrile disease
ulceroglandular tularemia: predominant form that occurs via infection of skin/mucus membranes. focal ulcers,and enlarged lymph nodes. incubation period of 21 days.
respiratory tularemia: more severe; occurs from inhalation. high fever, chills, malaise, pneumonia, cough.
oculoglandular tularemia: direct contact of bacteria
GI tularemia possible
typhoidal tularemai: systemic symptoms w/o regional ulcerations or swollen lymph nodes
What is one clinical sign of respiratory tularemia?
pulse temp dissociation: no rise in pulse rate with fever
What makes Francisella tularensis pathogenic?
bacteria can replicate in many different host cell types, but especially macrophages. entry is mediated by phagocytosis, followed by replication and alteration of phagosome maturation.
How do you diagnose and treat tularemia?
Diagnosis is very hard: bacteria must be grown on chocolate agar for several days. ID is confirmed with special antisera. Careful, because tularemia can look like other diseases (strep, staphy, mono, plague, etc.).
if recognized early, responds very well to streptomycin.
What disease is caused by yersinia pestis?
PLAGUE
How does the bubonic PLAGUE present?
caused by Yersinia pestis. presents 2-10 days following exposure.
symptoms: swollen and very tender lymph gland (“bubo”) and pain. Often seen in the femoral, inguinal or axillary regions. Bubos are filled with bacteria
How does septicemic plague present?
untreated bubonic plague invades the bloodstream: severe and usually fatal endotoxic shock.
Pneumonic plague presentation
severe respiratory illness. high fever, chills, cough, resp. difficulty, bloody sputum. Human-human transmission possible. Incubation of 3 days, followed by death about 3 days later if untreated
How do you treat plague?
gentamycin or doxycycline
Yersinia pestis: gram, morphology, ox needs, motility, shape.
pleiomorphic bacillus gram negative, BIPOLAR gram staining facultative aerobe nonmotile facultative intracellular pathogen
How does yersinia pestis cause disease?
- non-encapsulated form enters during the feeding of an infected flea.
- some non-encapsulated organisms are taken up by histiocytes, and capsule is resynthesized.
- Encapsulated organisms rapidly proliferate and then get released.
- bacteria replicate extracellularly and the infection spreads. Often leads to a fatal inflammatory disease.
What are some of the virulence factors associated with yersinia pestis?
V and W proteins (associated with septicemia)
Yops:
envelope F1 antigen
coagulase/plasminogen (attenuate phagocytosis)
Brucella abortus: reservoir, how it is spread
many zoonotic reservoirs: cattle, sheep, goats, pigs, dogs
Spread: consumption of unpasteurized dairy products, inhalation of aerosolized bacteria, abrasions in the skin. human to human spread is very rare, but is possible. inhalation is also possible (rare for naturally occurring disease but could be a bioterror concern). Very low infectious dose- less than 10 organisms needed.
Brucella characteristics: gram, motility, shape, growth, ox needs
gram negative non-motile coccobacillus strict aerobes very slow growing: up to 6 wks!
Brucellosis: symptoms
aka undulant fever
affects organs rich in erythritol: breast, uterus, epididymuis.
can lead to late-term abortion
can occur acutely or with undulant fevers that cycle with the time of day- peaks in evening and normalizes by morning (chronic form). chronic form is accompanied by severe depression, osteoarticular disease, hepatomegaly, and splenomegaly. caused by persistence in phagocytic cells and low levels of bacteria.
What are some characteristics of the clostridium species? Gram stain, shape, ox needs,
gram positive, spore forming, obligate anaerobes
most species are saprophytes
Clostridium botulinum: food posing form. where/how is this seen? symptoms?
spores can contaminate lots of different things, esp. in moist, low acid foods (meats, veggies, canned foods) with less than 2% O2. Symptoms: weakness, dizziness, dry mout 8-36 hrs after ingestion. followed by nausea, vomiting, and neuological symptoms like blurred vision, dysphagia (difficulty swallowing), difficulty speaking, paralysis
NO FEVER
infant botulism: what happens? symptoms?
toxingenic infections in infant GI systems. follows ingestion of the spores.
This is why babies under 18 mo. CAN’T EAT RAW HONEY.
symptoms relatively similar: constipation, then muscle weakness and paralysis. trouble controlling head
Wound botulism: symptoms. who is most susceptible?
symptoms: double vision, dry mouth, difficulty speaking, weakness or fatigue, wound pain.
usually seen only in IV drug users, esp. those who inject heroin right into tissue instead of veins. No GI symptoms.
How does the C. botulinum toxin work?
It prevents ACh release at the neuromuscular junction: no contraction can occur and you see flaccid paralysis.
How do you treat botulism? What serotype of botulism is most common?
administer antitoxin
type A is the most common toxin.
Describe the pathogenesis of C. dificile (steps)
- an event occurs: prolonged antibiotic use, surgery, etc.
- spores germinate and cells multiply
- c. diff aderes to mucus and erythrocytes
- c diff makes toxins
