Bacterial upper respiratory infections Flashcards Preview

Year 1 Microbiology > Bacterial upper respiratory infections > Flashcards

Flashcards in Bacterial upper respiratory infections Deck (49):

What tissues of the URT are considered sterile?

1. Mastoid air cells2. Middle ear3. Sinuses4. Trachea5. Bronchi and bronchioles6. Alveoli


What URT tissues are colonized by bacteria?

1. Nasal cavity2. Nasopharynx3. Pharynx


What are the normal flora of the nose?

1. Staph epidermidis2. Staph aureus 3. Corynebacterium spp.


What are features of staph epidermidis and staph aureus?

1. Gram positive2. Cocci clusters3. Facultative anaerobes


What are features of corynebacterium spp.?

1. Gram positive2. Rod 3. Pleomorphic4. Non spore forming


What are the normal nasopharynx flora?

1. Streptococcus2. Viridans strep group 3. Moraxella catarrhalis4. Bacteroides


What are the Viridans strep group pathogens?

1. S. mutans 2. S. mitis 3. S. milleri 4. S. salivarius


What are features of the strep pathogens that colonize the nasopharynx?

1. Gram positive2. Cocci chains


What are features of the moraxella catarrhalis group?

1. Gram negative2. Diploid coccobacillus 3. Aerobic


What are features of the bacteroides group colonizing the nasopharynx?

1. Strict anaerobe2. Gram negative3. Bacilli


What URT pathogens of the nasopharynx are associated with seasonal fluctuation?

1. Strep pneumoniae 2. Haemophilus influenzae 3. Neisseria meningitidis 4. Moraxella catarrhalis


What are the features of the URT strep pathogens?

1. Gram positive2. Cocci in chains 3. Catalase negative


What are the group designations for the URT strep pathogens?

1. Group A - S. pyogenes - beta2. Group B - S. agalactiae - beta3. Group D - S. bovis, Enterococcus faecalis4. a hemolytic - S. pneumoniae


What is the causative agent of strep pharyngitis?

Strep pyogenes


What differentiates S. pyogenes from the other throat streptococci?

B hemolytic


What does the Rapid Strep Test target?

Cell wall antigen


What are features of S. pyogenes pathogenicity?

1. M protein - antiphagocytic, essential for virulence2. F protein - mediates attachment 3. Capsule - hyaluronic acid, antiphagocytic 4. Strep pyrogenic exotoxins - responsible for severe consequences


What is essential for S. pyogenes virulence?

M protein


What causes Scarlet Fever?

1. Occurs during acute illness of S. pyogenes2. Erythrogenic toxin (one of SPEs) is released from infection site and enters blood stream 3. Redness of skin and white coating on tongue


What is the cause of rheumatic fever?

1. Due to an acute inflammatory process 2. Stems from throat S. pyogenes infection 3. Autoimmune cross reaction with host tissues


What is the cause of toxic shock syndrome?

1. May begin at site of any Group A disease2. Usually skin and soft tissue 3. Nausea, vomiting, diarrhea, hypotension shock and organ failure


What is the cause of necrotizing fasciitis?

SPE release


What are post streptococcal infection sequelae?

1. Acute glomerulonephritis 2. Deposition of antigen-antibody complexes in glomeruli3. Edema, hypertension, hematuria, proteinuria, decreased serum complement levels


What group is S. pyogenes in?



What is the causative agent of diptheria?

Corynebacterium diptheriae


What are the features of corynebacterium diptheriae?

1. Variable shape2. Nonmotile3. Non spore forming4. Gram positive5. Rod ("Chinese letters")


What is the diptheria virulence factor?

1. Diptheria toxin 2. Strain must be lysogenized by a bacteriophage to gain toxin producing capability


What are the symptoms of diptheria?

1. Begins with mild sore throat, slight fever, high fatigue and malaise2. Neck swelling is dramatic3. Whitish gray membrane forms on tonsils and throat or in nasal cavity 4. Heart and kidney failure, paralysis can rapidly follow


What is the mechanism of diptheria toxin infection?

1. A and B subunit on toxin 2. B binds3. A inactviates EF-2 - halts protein synthesis and induces cell death


What are the two main causative agents of pinkeye?

1. Haemophilus influenzae - gram negative rod2. Streptococcus pneumoniae - pneumococcus


What are the main causative agents of otitis media / sinusitis?

1. Haemophilus influenzae - gram negative rod2. Streptococcus pneumoniae - pneumococcus


Haemophilus influenzae and streptococcus pneumoniae otitis media infections are generally responsive to what antibiotic therapy?



What are the features of Haemophilus influenzae?

1. Small, pleomorphic 2. Gram negative3. Rods or coccobacilli 4. Facultative anaerobes, fermentative


What is the main virulence factor in H. influenzae?

Antiphagocytic polysaccharide capsule


What is the treatment for H. influenzae?

Broad spectrum cephalosporins


What are the properties of chlamydia bacteria?

1. Inner and outer membranes similar to gram negative 2. Contain both DNA and RNA 3. Prokaryotic ribosomes 4. Synthesize their own proteins, nucleic acids, lipids 5. Can form different developmental forms - elementary bodies and reticulate bodies


What are the properties of the two chlamydia infection forms?

1. Elementary bodies - metabolically inactive, infectious 2. Reticulate bodies - metabolically active, noninfectious


Chlamydia trachomatis is responsible for what diseases?

1. Trachoma2. Adult inclusion conjunctivitis3. Neonatal conjunctivitis 4. Infant pneumonia5. UG infections


What is the pathogenesis of chlamydia infections?

1. Direct destruction of host cells during replication 2. Host inflammatory response further exacerbates


What are the immunological properties of chlamydia?

1. Does not confer long lasting immunity 2. Reinfection usually induces a vigorous damaging inflammatory response


What is the virulence of chlamydia?

Intracellular replication / prevention of phagolysosome formation


What are features of trachoma?

1. Follicular conjunctivitis with diffuse inflammation 2. Eyelids can turn inward due to scarring 3. Corneal abrasion and scarring


What are features of adult inclusion conjunctivitis?

1. Acute follicular conjunctivitis 2. Mucopurulent discharge, keratitis, corneal infiltrates, some vascularization


What are features of neonatal conjunctivitis?

1. Infants exposed to C. trachomatis at birth 2. Conjunctival scarring and corneal vascularization occur


What are features of infant pneumonia?

1. Onset 2-3 weeks after birth 2. Bronchitis with a dry cough, afebrile


How is C. trachomatis be diagnosed?

1. Cytologic, serologic, culture findings2. Direct detection of C. trachomatis antigen in clinical specimen3. C. trachomatis through use of molecular probes


Chlamydophila pneumoniae is an important cause of what conditions?

1. Pneumonia2. Bronchitis3. Sinusitis


What are features of Chlamydophila pneumoniae infections?

1. Most severe infections involve only one lung2. Cannot be distinguished from other pneumonias 3. Could be involved in atherosclerosis


What are features of Chlamydophila psittaci?

1. Parrot fever2. Present in blood, tissue, feces, feathers of infected birds 3. Infection via respiratory tract 4. Spreads to reticuloendothelial cells of liver and spleen 5. Causes focal necrosis, then spreads6. Result is lymphocytic inflammatory response on the alveolar and interstitial spaces