Question | Answer |
How is TB transmitted? | via respiratory droplets |
What does a positive Mantoux or tine test indicate? | TB infected the person at some time |
How has TB tx changed? | requires antibacterial susceptibility testing to find effective drugs--tx with triple ABT for 6 mos-2 yrs |
Describe the pseudomembrane caused by diphtheria | seudomembrane--forms in pharynx--can cause asphyxiation--should not be removed--risk of bleeding to death |
What is unusual about the morphology of Bordetella pertussis? | Bordetella pertussis is a coccobacillus |
Who is most susceptible to pertussis? | young children |
How is pertussis recognized? | by paroxysmal sound when coughing stops long enough for inspiration |
What does a paroxysm cause? | whooping sound that occurs when coughing must stop for O2 replacement by stressful inspiration |
What 2 systems are used to classigy the streptococci? | Lancefield's C carbohydrate grouping (A,B,C, etc) and by hemolysis type |
What are the common, significant sites of human infection by the streptococci? | common, significant sites of human strptococcal infection are throat, oral cavities, vagina, and intestines |
In what relatively new site is group B strep (strep agalactiae) found today? | human vaginal tract |
Which people are at risk for which diseases from group B strep? | newborns are at risk for septicemia and meningitis from group B strep |
What color will viridans step produce on blood agar? What particular disease does viridans strp cause? | viridans strp will produce a greenish tinge on blood agar--viridans strep causes subacute endocarditis |
what chemical componenet of the cell wass is used to differentiate the above streptococci? | C carbohydrate is used to differentiate streptococci |
What relation does the pneumococcal (strep pneumoniae) capsule have to virulence? | oly encapsulated strains are virulent |
What relation does the pneumococcal (strep pneumoniae) capsule have to do with the number of times an individual can acquire qneumococcal pneumonia? | ninety times because there are ninety serovars |
What are the epidemiology and pathology of the pneumococcus? | spread from human to human--pus-like exudate and fluid accumulation in the lungs--x-rays/rusty sputum help dx--death by drowning--lungs fill with fluid |
How should infection with the pneumococcus be prevented? | infection with pneumococcus prevented with pneumovax--immuity lasts 5 yrs--booster shots recommended if no hypersensitivity develops |
List two unusual characteristics about Mycoplasma cell envelopes | cell has no cell wall (peptidoglycan layer) and membranes that contain sterols |
Describe how to diagnose the disease caused by Mycoplasma pneumoniae | best dx is to observe increasing tiiters of cold agglutinins that cause RBC agglutination at refrigerator temps |
Describe the source, symptoms, and at-risk individuals for legionellosis. On what does Legionella pneumophila usually feed? | sources are aerosols from lakes, streams, cooling towers--sx--resp. distress--at risk--heavy smokers and drinkers--feed on amoebae |
How do contacts of meningitis patients protect themselves? | health-care workers/family contacts--at risk to acquire meningitis from pts and need prophylactic tx with rifampin |
What is the most common cause of meningitis? | Hemophilus influenzae--organism initially isolated from flu pt--gram-neg. pleomorphic, rod-shaped, aerobic organism--requires carbon dioxide and vit. to grow--90% fatal if untx--1/3 have perm. mental damage if tx immediately |
How soon does tx of meningococcal meningitis need to start? | tx of meningococcal meningitis needs to start immediately |
How are C. pneumoniae cultured? | can't be grown on bacterial media--must be grown inside of human cells in culture--can't produce own ATP and must acquire from host cell--obligate intracellular pathogens |
What virulence activities are associated with each layer of streptococcus pyogenes (group A strep)? What virulence activities are associated with major toxins? | C carbohydrate prevents lysozyme from lysing cells--M protein--displays 90 types--attachment factor and antiphagocytic--hyaluronic acid capsule masks bacteria--streptolysins damage membrane of heart cells and WBCs |