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74 Cards in this Set
- Front
- Back
Diptheria is:
Sporulating/ non-sporulating Anaerobic/aerobic Gram +ve/-ve? |
Non-sporulating, aerobic, Gram +ve
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Diptheria grows in...
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Upper respiratory tract (throat). NOT in blood
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Diptheria produces what in back of throat?
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Greyish pseudo membrane. Produces toxins and limits respiration
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Diptheria toxins...?
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Cleave IgA, Cord Factor is toxic for phagocytes, toxin stops protein synthesis - cell death
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Diptheria vaccine is...?
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DTaP - Diptheria, tetanus and whooping cough
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Diptheria treatment?
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Horse antitoxin, antibiotics (given early)
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Mycobacterium tuberculosis is: Airborne/ non-airborne?
Slow/fast growing? Gram +ve/-ve? Shape? |
Airborne, slow growing, non-sporing, gram +ve bacillus
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TB causes damage because of...?
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Host response. Unable to destroy organism
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Percent of TB cases symptomatic? Symptoms are?
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10% symptomatic. Fever, fatigue, weight loss, cough, bloody sputum, death
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Key part of TB illness...?
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Caseus necrosis
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Treatment for TB?
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Antibiotics for 6-18months, isoniazid, rifampin
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What are the resistant strains of TB?
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MDR-TB (Multiple drug resistant)
XDR-TB (Extremely/Extensively Drug Resistant) |
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Effectiveness and type of vaccine for TB?
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Live attenuated, 0-80% effective. Recent resurgence of TB
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Gonorrhoea neiserria is..
motile/non-motile? Gram -ve/+ve? Shape? |
Non-motile, gram -ve, diplococcus, human pathogen only
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How many new cases per annum of gonorrhoea?
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62million, many asymptomatic
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Chance for male/ female of getting gonorrhoea after 1 encounter?
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50% for females, 20% for males. No lasting immunity
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Gonorrhoea adheres to body by.... on.......epithelium
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pili, columnar
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Gonorrhoea rapidly multiples in......of cells, some localised, some......
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vacuoles, systemic
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Gonorrhoea binds to.......... resisting complement killing ,......, Undergoes........ variation frequently
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Gonorrhoea binds to SYALIC ACID resisting complement, killing IgA PROTEASE Undergoes ANTIGENIC variation frequently
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Gonorrhoea causes in males?
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urthritis, purulent discharge, dysuria
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Gonorrhoea causes in females?
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urethritis or cerviatus, endometriuts, salpingitis (oviduct infection) and pelvic inflammatory disease
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What is Opthalmia neonatrum?
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Eye infection of babies born to gonorrhoea infected mothers
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What is the treatment for gonorrhoea?
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Single antibiotic injection. Resistance increasing, no lasting immunity and no vaccine
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Chlamydia is...?
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A very small bacteria, like a virus
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Chlamydia has a unique life cycle - 2 forms. Elementary bodies are.... Reticulate bodies are...
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Elementary bodies are inactive and extracellular
Reticulate bodies are active and intracellular multipliers Chlamydia differentiates between the two |
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Chlamydia can generally cause?
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Genital + eye infections and pneumonia
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In women chlamydia can cause??
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cervical infection which can lead to increased susceptibility to HIV; infection of the fallopian tubes leading to ectopic pregnancy, PID and infertility. Infection of an infant, due to cervical infection, can cause eye infection and pneumonia.
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In men chlamydia can cause??
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Urethral infection leading to painful urination and discharge and reactive arthritis.
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Chlamydia .... the host immune system. Damage is due to......... of cells.
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avoids, direct destruction
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Repeated exposure to chlamydia causes?
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More severe disease
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Treatment for chlamydia?
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Antibiotics, no vaccine
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MRSA is?
Gram +ve/-ve? Shape? Aerobic/ Anareobic/ faculatative? Fastidious/ non-fastidious? |
Methicillin Resistant Staphylococcus aureus is Gram +ve, coccus, clutered growth of golden colonies, facultative anaerobe and non-fastidious
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MRSA causes a variety of disease, some examples are...
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food borne, scalded skin syndrome, boils, can be catheter borne, post-operative, bone infection, can cause pneumonia, toxic shock syndrome, cytotoxic storm
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MRSA produces...
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Cell and tissue destroying toxins, capsule and forms biofilms which stick to plastic (catheters)
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MRSA prevents...
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opsonisation - binds IgG Fc
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MRSA antibiotic resistance...
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encodes mutant penicillin binding protein
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MRSA is...
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Difficult to treat but no more virulent that SA.
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MRSA has a tendency to...
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Infect younger age group, cause severe skin infections and lethal haemolytic pneumonia
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Treatment for MRSA includes...
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Vancomycin, but resistant strain VRSA.
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What drugs work against VRSA?
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Zyrox and Syneraid. No vaccines.
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Clostridium difficile is?
Gram +ve/-ve? shape? Anaerobe/ aerobe? Sporulating/ Non-spoulating? |
C. difficile is gram +ve rod, strict anaerobe, spore forming. Resistant to disinfectants.
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C. difficile can cause?
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Mild self-limiting diahorrea, severe diahorrea and abdominal pain, life threatening pseudo-membraneous colitis (inflammation and necrosis of the colonic mucosa)
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C. difficile infection is caused by?
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Disruption of the normal flora
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Symptoms of C. difficile are due to? (first toxin)
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Toxin A (enterotoxin). Haemotactic factor for neutrophils release cytokines - cause hypersecretion of fluid and haemorrhagic necrosis
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Symptoms of C. difficile are due to? (second toxin)
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Toxin B (cytotoxin) destroys cytoskeleton of affected cells resulting in cell death. Toxin A -ve and B +ve strains still cause disease.
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Emergence of new C. difficile ribotype.... causes?
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Ribotpye 027, epidemic strain, increased severity, mortality and relapses
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Treatment of C. difficile?
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Discontinuation of implicated antibiotic; therapy with vancomycin or metronidazole; probiotics; faecal transplants
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Prevention of C. difficile?
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Vaccines under clinical trials, but elderly most at risk - impact of vaccine toxin on gut may be problem
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Control of C. difficile?
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Patient isolation, hygiene measures, hospital surveillence and control measures.
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Salmonella is?
Motile/ non-motile? sporing/ non-sporing? Gram +ve/-ve? Shape? Aerobic/ Anaerobic/ Facultative? |
Motile, non-sporing, gram -ve rods, facultative anaerobes, >2000 serotypes
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S. typhi causes?
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Typhoid fever - NO animal host
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Salmonella is food borne/ poisining? Animal source?Examples of species names (2)?
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Salmonella that causes food poisoning is from an animal source e.g. S. enteriditis, S. typhimuriam
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Salmonella causes what symptoms?
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Fever, diahorrea, vomitting, abdominal pain. Lives in food animals GI tract. Usually causes local enteritis, but sometimes goes into bloodstream.
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Cause of salmonella infection?
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Cross contamination, improper cooking.
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How does Salmonella cause disease?
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Toxins not clearly demonstrated. Invades mucosal surface in intestine. Facultative intracellular parasites. Bacteria passes through mast cells then taken up by macrophages, in which salmonella multiples and lyses the macrophage. Once recovered usually cease to secrete organism, but some people become carriers.
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Important part of Salmonella pathogenicity island?
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Injector
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Salmonella causes damage by?
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Inflammation causes damage, which causes diahorrea. Villi essentially get destroyed, stopping fluid absorption. Salmonella survives in macrophages.
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Campylobacter is?
species? Aerobe/ microaerophile/ anaerobe? motile/ non-motile? Gram +ve/-ve? Shape? |
C. jejuni is a microaerophile, slender, motile, Gram -ve curved or spiral rods.
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Does Campylobacter cause animal disease?
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Colonises poultry, but cause no animal disease.
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How do humans get infected by Campylobacter?
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Meat is infected at slaughter. Virulence is associated with the flagella.
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What is the greatest cause of acute diahorrea in man?
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Campylobacter
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Are Campylobacter zoonotic?
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Yes - aqcuired from animal via food (or direct contact). Facultative intracellular parasites.
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How does campylobacter cause disease?
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Invade mucus membranes of gut and produce cytotoxins responsible for tissue damage and inflammatory diahorrea.
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Vibrio cholerae is?
Gram +ve/-ve? shape? flagella? |
Disease of war and natural disaster. Gram-ve, motile, curved rods, 1 flagella.
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How does V. cholerae cause disease?
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Sits on surface of illeal epithelium and produce toxins which cause disease. Associated with contaminated water e.g. Ganges.
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Father of epidemiology?
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John Snow - 1847, cholera, water pump story
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How high is transmission of infective agents? Animal disease too?
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Only human disease, transmit 10^12 organisms per day with diahorrea.
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Where does v. cholerae live?
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Lives in salt and fresh water, forms biofilms.
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Are most people symptomatic? What types of cholera are there?
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Most people are asymptomatic but can still shed organism. Number of types - O1 serotype, classic biotype and El Tor biotype and new 0139 serotype.
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Incubation time? symptoms? treatment?
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Incubation time - 2-3days. Profuse watery diahorrea 1L/hour. Death due to hyperbolemic shock and multiple organ failure. Use cholera cot and bucket. Rehydrate by drip/ oral salt solution which MUST have glucose in it.
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Infective dose of cholera? colonisation depends on? toxin production?
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INfective dose of 10^9-10^11 required. Colonsation depends on motility, production of mucinase (protease) and TCP adhesion. Toxin is A/B subunit encoded by CTX phage. Receptor for toxin is colonisation factor TCP. Toxin hijacks second messenger signalling system.
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Additional cholera toxins?
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Zot: Zonula occludens toxin - affects intracellular tight junctions
Ace: accessory cholera toxin - causes increased transmembrane ion transport. |
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Immunity to cholera?
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Surface Ag required to prevent infection. Killed whole cell vaccine poorly effective. New oral vaccines better for for stimulating mucosal activity. WC/B - heat killed and formalin killed cells of various serotypes and biotypes and B unit of cholera toxin. Live attenuated vaccine - A subunit gene deleted.
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Shigellosis is?
motile/ non-motile? Gram +ve/-ve? Species and severity? |
Dysentry, non-motile, Gram -ve rods, S. sonnei usually mild, person to person disease; S. flexneri, S. boydii more severe - travellers diahorrea; S. dysenteriae most severe - pandemic.
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