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25 Cards in this Set

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  • Back
What genus is an endospore aerobe?
What two main species of this genus cause infection in humans?
-Bacillus
-Anthracis and cereus
What does B. cereus cause and how?
What virulence factor does it use?
-Food poisoning from rice dishes
-Enterotoxin
How does B.anthracis remain in soil for so long?
What disease does it cause?
How do humans get it?
-Produces endospore.
-Anthrax
-From contaminated animals or animal products
What are the three main forms of anthrax?
What do they commonly cause?
-Inhalation, gastrointestinal and cutaneous.
-Septicaemia and meningitis.
How is the inhalational form of anthrax contracted?
What does it cause?
Mortality if untreated?
-Spore inhaled into alveoli and ingested by macrophages carried to mediastonal lymph nodes.
-Haemorrhagic necrosis of mediastinal lymph nodes with pleural effusion; 1st phase flu-like, 2nd phase fever, shortness of breath, hypoxia, septicaemia and meningitis.
-100%
How is cutaenous form of anthrax contracted?
What does it cause and symptoms associated?
Untreated mortality?
Spore inoculate in previous breach of skin.
- Causes primary, itchy lesion progresses to black scab surrounded by edema associated with fever and malaise.
-20%
How is gastrointestinal anthrax contracted?
What does it cause?
Untreated mortality?
Via poorly cooked meat.
-Ulceration of mucosa followed by regional lymphadenitis, edmea and tissue necrosis. Another form involves terminal ileum and caecum with nasuea, vomiting and bloody diarrohea. Both lead to systemic sepsis.
-100%
What therapy is given to treat?
How long should be treatment be given for and why?
Antibiotics either penicillin, doxycycline or ciprofloxacin (empirical drug in bioterrism.)
-60 days because of possible delayed germination of spores
What genus is an endospore anaerobe?
Clostridium
What are the four species of clostridium?
C. perfringens, C. difficile, C. botulinum, C. tetani
What are the two types of main disease C. perfringens causes and what occurs in these infections? What happens when it is ingested with food rich in trypsin inhibitors?
Gas gangrene (invasion and liquefactive necrosis of muscle and tissue) and food poisoning (crampy abdominal pain and diahorrea.
Necrositising bowel disease due to beta-toxin.
What toxin does C. tetani produce? How is it contracted? How does it produce its symtpoms?What are the clinical features?
Neurotoxin
Through wound puncture.
Travels from peripheral nerves to central to block inhibitory impulses to MN.
Trismus (increased masseter tone), risus sardonicus (increased orbuclaris oris tone), abdominal rigidity, generalised painful spasms which can compromise respiration.
What toxin does C.botulinum produce? How is it transmitted inot body? How does it produce it symptoms? What condition does it cause and its symptoms?
Neurotxoin
Ingested in food
Carried by bloodstream to targets: peripheral neuromuscular junctions and automatic synapses.
Botulism, acute bilateral cranial neuropathies, descending ymmetrical weaknessand respiratory impairment.
What is C. difficile a coloniser of? Who is it most common in and what % is it in adults? What toxin does it produce? What does it cause?
-The bowel
-Infants and those in hospital, 3% of adults are carriers.
-Enterotoxin
-Antibiotic diarrhoea or pseudomembranous colitis
What are the three genera of non-endospore aerobes of regular shape?
-Listeria, Lactobacillus and Erysipelothrix.
What are Lactobacillus commensals of? What is the importance of Lactobacillus in the body? Are they pathogenic?
Lactobaccilus are commensals of the oral cavity, gastrointestinal tract and vagina. The are responsible for keeping the vagina pH at optimal level. Rarely are they pathogens.
What is the major species of Listeria? How is it contracted? Who is particularly at risk? What clinical syndromes does it cause?
-L. monocytogenes
-Via food
-Pregnant women, young, elderly and immunocompromised.
-Bacteraemic flu-like illness, septicaemia +/- meningitis (70% mortality) and granulomatosis infantiseptica, infant born with multiple abscesses and is often stillborn.
What is the only species of Erysipelothrix to cause infection in humans? How is it acquired? What does it cause?
-E. rhusiopathiae
-Handling meat, poultry, fish and crustaceans it enters through abrasions on hands and arms.
-It causes painful, raised areas of information that fade centrally as it spreads.
What genus is non-endospore forming aerobe with an irregular shape? What is its morphology? What are its fours main species?
-Genus Corynebacterium
-Coryneform
-C. diptheriae, C. minutissimum, C. jeikeium, C. urealyticum
What does C. diptheriae cause and clinical symtpoms? What toxin does it produce and which organs can this affect? How may it result in death?
Diptheria with superficial infection of pharynx becoming more severe extending down trachea.
Exotoxin, affecting heart (arrythmias) and nerves (neruitis, paralysis).
Excessive inflammation, swelling and exudation forms a obstructive membrane causing asphyxiation.
What is C. jeikeium a commensal of? What infections does it cause?
-Skin
-Infection of IV cannulas and other devices and can cause septicaemia and endocarditis
What does C. urealyticum do and in doing this what does it cause? What are the features of its infection?
It splits urea resulting in UTIs.
Present in pre-existing abnormal urinary tract, urea splitting produces ammonia which desposits causing inflammation and may cause renal stones.
What does C. minutissimum cause?
Erythrasma, brown red discolouration of skin folds, esp. in groin.
What is the shape of the nonendospore aerobic actinomycetes? What do many bacteria in this group cause? How do they cause this?
-Filamentous
-Skin and subcutaneous lesions called actinomycotic mycetomas.
-Inonculation in skin after trauma, gradual production of subcutaneous swelling contained suppurative granulomas and mutlip sinus tracts, over months to years cause destruction of unferlying fascia, bone and muscle destorying tissue.
What genus causes infection other than mycetomas from the aerobic non-endospore producing actonmycetes?
What is its main species?
What may is cause?
-Nocardia
-Asteroides
-Pneumonitis following inhalation and haematagenous dissemination to any ogran causing brain abscess or skin lesions.