Test Flashcards
(109 cards)
What are following strategies for combating drug resistance
- Administer a combination of two antibiotics with different modes of actions
- Develop inhibitors of drug-inactivating proteins and efflux transporters
Define the MIC
the lowest concentration of an antibiotic that is inhibitory to bacterial cell growth
A patient has systemic febrile illness, which item in the history would indicate the highest risk for Brucella infection
Brucella: Bruce’s farms
contact with livestock or animal products
What antigens are effective for agglutination of intact bacteria by antibody?
-pili
-flagella (H antigen)
-O-antigen
-Teichoic acid
Capsule (K antigen)
-peptidoglycan
(things outside of the bacteria, components of the cell wall.
Which characteristic of mycobacterium tuberculosis is believed to be the most essential to its transmission?
Their impermeable lipid rich envelope
-making them highly resistant to heat, cold and drying allowing them to persist for long periods of time in the environment
Gram stain has been performed to get the stain and the shape. An additional rapid test that may be preformed would be:
Serotyping using slide agglutination
When are each of these plates useful; Lowenstein-Jensen medium BCYE agar Chocolate agar Thayer-Martin Tellurite-containing medium such as Regan Lowe
Lowenstein-Jensen medium: standard medium used to grow M. tuberculosis
BCYE: clue for legionellosis
Chocolate agar: required to grow Neisseria species or Haemophilus inflenzae from sterile sites such as CSF
Thayer-Martin: chocolate agar with antibiotics used to culture only Neisseria species
Tellurite: is a clue to C- diphteriae
18 yr old college freshman living in university develops headache, neck stiffness, and fever. Gram stain of the CSF shows Gram-negative bacteria. A latex particle agglutination test confirms bacterial meningitis. The causative agent is most likely
Neisseria meningitidis
Haemophilus influenza is only likel except for a 3 month to 5 year old child who has not been vaccinated as a child.
(young adult, crowded living conditions) is the giveaway to neisseria meningitidis
11 yr old girl, has gastrointestinal infection with cramping and watery stools. After several days she begins to pass blood per rectum and is hospitalized. She has decreasing urine output with rising blood urea nitrogen. . Total blood count reveals anemia and the peripheral smear is remarkable for fragmented red cells. What is the agent
Shigella sonnei - what is described is bacterial dysentery (blood and mucus in stool) `
After extensive oral surgery a 66 yr old patient who had rheumatic fever did not take prescribed perioperative prophylactic antibiotics and developed sub acute infective endocarditis. Which is the causative agent
Rheumatic fever was caused by Strep pyogenes
Viridians streptococci - which are part of the normal oral flora, are very good at attaching to damaged heart valves when they enter circulation after oral surgery.
women went to peru, she develops profuse, water diarrhea with flecks of mucus, both are hospitalized because of severity and rapidity of dehydration but she is not febrile. What is the agent?
Vibrio cholera
what is a common virulence factor for bacteria that colonize mucosa?
IgA protease
ex. Neisseria meningitidis, streptococcus pneumoniae
What do chloramphenicol, tetracycline and erythromycin all have in common?
They inhibit the 70S ribosome.
What are the five most common cases of food poisoning world wide.
- Norovirus
- Salmonella
- Clostridium perfingens
- Campylobacter
- Streptococcus
What are the five most fatal microbes that cause food illness
- Vibrio vilnificus
- Clostridium botulinum
- Listeria
- Mycobacterium bovis
- Hepaptitis A
What are examples of nontreponemal tests and specific treponemal tests.
The difference between the two is one you are looking for antibodies the syphillus produces, the other is you are looking for what the body produces against syphillis.
Nontreponemal tests: syphillus infection leads to generation of antibodies to common antigen of host and these antibodies are called reagin.
VLRL
RPR
Complement fixation: reagin in serum can fix complement in presence of cardiolipin
Specific: you detect antibodies directly towards treponema.
- FTA-ABS (indirect immunofluorescence)
- TPHA - RBCs treated to adsorb T.pallidum on surface, then mix with serum?
What are general characteristics of spirochetes and what are the ones you need to know
They are Gram Negative, coiled cell wall, and motile. They are best visualized using dark field microscopy. Spirochetal infections usually have stages of infections.
- Leptospirosis - Leptospira interrogans
- Treponema - syphillis
- Borelia burgdorferi - lyme disease
- Borellia recurrentis - relapsing fever.
Distinguish endemic and epidemic relapsing fever
I would think about if there is a middle man or not.
Epidemic: human to human transmission via the human body louse and usually happens during times of difficulty.
Endemic: there is another vessel. From animal to tick to human
Characteristic: sudden onset of fever with chills, severe headache and malaise which ends abruptly. Severity of symptoms decrease with each relapse.
Which organisms are transmitted through contaminated water?
- Leptospira interrogans - animal urine
- M. Marinum
- Legionella pneumonia - aerosol from water supply
Hawaiin Patient has conjunctiva. Other than that kinda okay and only had a mild fever. Patient has been swimming in their pool after the dog was in there.
Leptospirosis.
What are the five serotypes of chlamydia trachomatis and their clinical manisfestations
- Ocular trachoma- the most common cause of blindness worldwide. Chronic conjunctivitis
- Inclusion conjunctivitis: Acute conjunctivitis which in adults, more than half also have UTIs
- UTI - most common cause of STD in America. The symptoms are largely asymptomatic. IN a woman the prolonged infection leads to urethritis, cervicitis and eventually PID (pelvic inflammatory disease) which leads to infertility. Men get urethritis, epididymitis, proctitis.
- Lymphogranuloma venereum - chronic infection of the lymphatic system. Swollen inguinal nodes
- Lymphogranuloma venereum
- infant pneumonia
What are general characteristics of chlamydia and the 3 species.
All chlamydia are obligate intracellular because they can’t synthesize ATP and they all share a unique lifestyle: As extracellular spores they are infectious stage, they get phagocytosed and form a reticular body (the second stage) and they live in the macrophage. The reticular bodies multiply, the cell ruptures and releases the Elementary bodies (spores). Difficult to stain but closer to Gram negative
- Chlamydia pneumoniae - mild upper respiratory tract infections but can also cause pneumonia and bronchitis
. - Chlamydia psittaci: fever, headache, sore throat, cough that comes later in disease
- Chlamydia trachomatis.
What are grouped under “Ricketssia and other related organisms”
Rickettsia & Orentia
Rickettsia typhi
Rickettsia akari
Ricketsia prowazekii
Ricketsia rickettsii
Erlichia and anaplasma
HGA/ anaplasma phagocytophilum
HGE/ Ehrlichia chaffeensis
Coxiella burnetti/Q fever
If you took an infected cell with Chlamydia trachomatis, looking under light microscopy what would you see?
A membrane bound inclusion body in the cytoplasm