KEY Wk 6 lec 3 Flashcards
gram positive vs gram negative
gram positive = blue
gram negative= red
gram positive have thick cell wall with peptidoglycan
aerobic vs anaerobic
aerobes need O2 to grow
anareobes- hard to grow with O2 (i.e. mouth, vagina, lower GI)
gram positive bacteria
staph and strep
staphylococci vs streptococci shape on microscope and what chemicals they make
staph= grapelike clusters
strep= chains
staph= make catalase (to degrade hydrogen peroxide)
strep= dont make it
lung abscess
necrotizing lung infection; pus-filled cavitary lesion
causes of lung abscesses
Aspiration of oral secretions (most common)
Endobronchial obstruction
Hematogenous seeding of the lungs (less common)
risk factors of aspiration
- depressed levels of consciousness
- impaired deglutition (swallowing)
- periodontal disease and poor dental hygiene
causes of aspiration
anaerobic bacteria
Prevotella melaninogenica, Peptostreptococcus, Fusobacterium nucleatum, Bacteroides species
anaerobic bacteria cause
Abscesses (Lung abscess) Actinomycosis
Botulism Clostridium-difficile-induced colitis
Food poisoning
Gas gangrene
Tetanus
cavitary lesion
gas filled space in pulmonary module
lung abscesses usually occur in
posterior segments of the upper lobes or superior segments of the lower lobes since these are the most frequent locations for aspiration
typical sx of lung abscess
productive cough, fever, sweats, weight loss
treat lung abscess with
beta-lactam/ beta-lactamase inhibitor or a carbapenem.
tuberculosis
top cause of infectious death worldwide (excluding covid19)
causes of tuberculosis
m. tuberculosis
family mycobacteriaece
also M. africanum, zoonotic M. Bovis
transmission of m. tuberculosis
pulmonary TB via droplet nuclei (cough, sneeze, speak) and stay in air for hours
tubercle bacilli via skin or placenta
m. tuberculosis is classified as
acid-fast bacilli
tuberculosis transmission risk factors
exogenous (crowded, poor ventilation)
endogenous (HIV, cancer, immunosuppressed)
primary TB vs post primary TB (adults) reactivation or reinfection
primary: kids, immunocompromised, right after get infected, can disseminate (miliary tuberculosis), not highly transmissible
reactivated: cavitation, more infectious
sx of tuberculosis
asymptomatic
OR
Fatigue, nocturnal sweating, increased temperature
Weight loss
Cough with expectoration of mucous or mucous-purulent sputum Hemoptysis
staph aureus make
coagulase and catalase and beta lactamase (degrade penicillin)
reservoir for staph aurerus
human reservoir, hand contact, colonize in nose
3 exotoxins of staph aureus
- Enterotoxin (food poison- gastroenteritis)
- Toxic shock syndrome toxin
- Exfoliatin (scalded skin syndrome or bullous impetigo)
pyogenic (pus forming) complications of staph aureus
Pyogenic (pus producing)
- Abscess, folliculitis, impetigo
- Local skin infection (ie. surgery)
- Disseminated (i.e. sepsis)