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)
Alpha vs beta hemolytic streptococci
Alpha hemolytic= incomplete lysis of RBC (i.e. s. pneumonia)
Beta hemolytic= complete lysis of RBC via hemolysin enzymes called streptolysin O and streptolysin S (i.e. s. pyogenes)
y-hemolysis= nonhemolytic
where do streptococci reside
Many are part of normal flora in throat, skin, and intestines disease when gain access to tissues or blood
s. pneumonia in oropharynx (pneumonia (esp. CAP), otitis media, meningitis, mastoiditis, sinusitis)
s. pyogenes in skin
s. viridans in pharynx causes subacute bacterial endocarditis
s. agalactiae causes neonatal sepsis and meningitis
strep pyogenes causes what
causes pharyngitis, cellulitis, impetigo, scarlet fever, toxic shock
2 disease : rheumatic fever and acute glomerulonephritis
- Pyogenic (pharyngitis and cellulitis)
- Toxigenic (scarlet fever, toxic shock)
- Immunogenic (rheum fever and acute glom.) (antibodies cross create and form immune complexes to damage normal tissue)
s pneumonia Is ____ hemolytic.
s pyogenees Is ____ hemolytic
alpha (incomplete)
beta (complete)
s pneumonia on agar
: alpha hemolytic, green on blood agar bc reduces iron in hemoglobin
s pneumonia virulence factors
-polysaccharide capsule (interfere with phagocytosis
- c-substance (react with CRP, a beta-globulin that indicated inflammation, risk of heart attack)
-CRP
-pneumolysin (alpha-hemolysis)
-IgA protease (cleave IgA)
s pneumonia is found in healthy people but will get disease sx if have
cerebral impairment, drugs or alcohol, abnormal respiratory tract, abnormal circulatory dynamics, splenectomy, chronic diseases
gram +
staph and strep
gram -
h. influenza
klebsiella penumonia
pseudomonas aeruginosa
bordetella pertussis
h influenza found in
Normal in upper respiratory tract
H influenza can cause
Cause pneumonia if HIV+ or immunocompromised
Contiguous spread: otitis media, sinusitis, bronchopneumonia
Disseminated spread: epiglottitis, meningitis, septic arthritis
bordetella pertussis causes
whooping cough
klebseilla pneumonia causes
-necrotizing lobar pneumonia if compromised by alcohol, diabetes, COPD
-UTI, bacteremia
pseudomonas aeruginosa can cause
Eyes (keratitis), ear (external otitis), skin, urinary tract, CNS, GI, respiratory (pneumonia, heart failure, cystic fibrosis)
atypical pneumonia causes
chlyamida trachomatis
mycoplasma pneuomnia
legionells
mycoplasma pneumonia special features
- No cell wall, gram negative
- Sterol in lipid bilayer
legionella from
- Aspiration of water or inhale contaminated aerosol
Legionnaires disease:
atypical, acute lobar pneumonia with multisystem sx (i.e. nosocomial)
pneumonia sx
- Fever
- Leukopenia (low WBC) or leukocytosis (high WBC)
- Altered mental status
- Purulent sputum
- Cough, dyspnea, tachypnea,
- Rales or bronchial breath sounds
- Worsening gas exchange
- One of: fever, leukopenia, altered mental status
- 2 of: purulent sputum, cough, dyspnea, tachypnea, rales or bronchial breath sounds, worsening gas exchange
1st line of defence/ innate immune against pneumonia
- Intact respiratory epithelium; cough reflex
- Nonspecific or innate immune factors (mucus, IgA, cytokines, spleen, complement, neutrophils, macrophages)
acquired immunity for pneumonia and in infants problem
- After colonization or exposure to cross-reactive antigens
- IgG antibody development for pneumococcal capsular polysaccharide
- Infants can only do B cell response and are at high risk to pneumococcal infection because of agammaglobulinemia
typical community acquired pneumonia vs atypical CAP causes
typical CAP: s. pneumonia, H.influenza, s. aureus
–> also viral (i.e. coronavirus, influenza, adenovirus)
atypical:
- Mycoplasma pneumonia
- Legionella
- Chlaymidia pneumonia
lobar pneumonia vs bronchopneumonia
Lobar pneumonia: uniform consolidation of lobe of lung (s. pneumonia)
Bronchopneumonia: in alveoli only
difference between community acquired and nosocomial (hospital) pneumonia
- Dif bacterial causes
- Dif antibiotic susceptibility (more drug resistance in nosocomial)
- Poorer health status and more severe in nosocomial
nosocomial pneumonia treatment
- High morbidity and mortality
- Can rarely find what infectious cause was so antibiotic treatment is empiric
hospital acquired vs ventilator acquired pneumonia casues
HAP:
Hospital acquired pneumonia
- S. aureus (MRSA)
- Streptococcus species
- P. aeruginosa
- Gram negatives (k. pneumonia, e coli, Enterobacter)
similar to VAP
Early HAP (5 days): e coli, h influenza, s aureus, s pneumonia
Late HAP: MRSA and Acinetobacter spp
VAP:
- Acinetobacter spp
- S. maltophilia
- Anaerobic
Ventilator acquired pneumonia occurs early
- If occurs before hospital day 4 if was healthy and no antibiotics then usually in oral flora with minimal drug resistance
sx of hospital vs ventilator pneumonia
HAP: Sx > 48 hours after admission to the hospital and excluding any infections present at the time of admission.
VAP: Sx > 48 hours following endotracheal intubation and mechanical ventilation
risk factors anaerobic causes of VAP
poor oral hygiene, decreased consciousness, manipulated airway
risk factors for hospital acquired pneumonia
Risk factors: treated with broad spectrum antibiotics, instrumentation of upper airway, contact with equipment, malnutrition, advanced age, swallowing disorder, systemic diseases, altered consciousness
S. aureus risk factors: previous influenza, ICU, traumatic brain injury, coma, diabetes, renal failure
MRSA risks: antibiotic therapy within 90 days, renal replacement therapy in 30 days, gastric acid suppressive agents, have MRSA recently,…
p. aeruginosa risks: antibiotics, structural lung disease..
multi drug resistant pathogen risks: antibiotic use, septic shock, acute respiratory distress syndrome, renal replacement…
