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23 Cards in this Set
- Front
- Back
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legionella is a parasite of what organisms?
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amoebas
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pseudomonas physiology?
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strict aerobe, gram neg rod, minimal growth requirements, tolerant to tough conditions (cannot survive boiling), biofilms
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pulmonary infections caused by pseudomonas as well as populatioons affected?
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chronic lung diseased, neutropenics, and all CF pts. benign tracheobronchitis in healtyh ppl. bilateral bronchopneumonia from resp equipment (high mortality), necrosis of lung tissue
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skin infections caused by pseudomonas...
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burn wounds (can lead to necrosis and sepsis), folliculitis, cellulitis, green nail syndrome, and ecthyma gangrenosum (round, indurated area with a black eschar and surrounding erythema)
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diseases caused by pseudomonas?
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UTI (usually from cath), ear infections (malignant and superficial external otitis), eye infections (from trauma), endocarditis (IV drug users)
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epidemiology of pseudomonas...
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found everywhere worldwide, 2nd most common cause of nosocomial pneumonia, 3rd most common cause of UTI, 4th most common cause of surgical site infections, 5th most common isolate overall
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who is most at risk for pseudomonas infections?
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neutropenics, very young or old, CF patients, burn pts, diabetics, pt previously treated with antibiotics, patients with indwelling catheters, med devices
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virulence factors of pseudomonas?
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either cell associated or extracellular products...
alginate capsule (lotsa muccous in capsule), adhesions (pili and non pillus proteins), pyocyanin, exotoxin A(immunosuppresive, dermatonecrosis, disrupts host protein synth), exoenzymes S and T (ADP ribosylators for bac dissemination), elastases, alkaline proteases (tissue destruction), phospholipase C (hemolysin and lipid breakdown), rhamnolipid (hemolysin, inhibits ciliary activity in airways), quorum sensing (higher pop density of bacs, more virulence factors they produce) |
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how do you diagnose pseudomonas?
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blue-green exudate in some infections, easy culture, smell sickly sweet, grape like, can do biochemical tests
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pseudomonas treatment?
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lotsa antibiotic resistance, multiple antibiotics usually needed: extended spectrum B lactam, aminoglycoside, newer quinolones, ceftazidime, aztreonam, macrolides (can interfere with quorum
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why is psedomonas so antibiotic resistant?>
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in the environment, it is exposed to antibiotic producing microorgs, it is selective for mutations, has several plasmids containing antibiotic resistance genes that can be exchanged.
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legionella physiology?
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aerobic, gram neg rod, needs cysteine and iron supplement, 3 day colony formation, poor stainer, need silver or fuchsin stain
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what legionella species is most responsible for human disease?
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legionella pneumophila, including serotypes 1-6
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risk factors for legionella?
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men over 55, smoking, emphysema, steroid, immunosuppressive therapy, chemo, diabetes
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how does one aquire legionella?
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from the environment, no person to person or animal reservoir
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diseases caused by legionella?
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legionaires (flu like, delirium, multilobar pneumonia, possible bacteremia, GI issues, 15-20% mortality) and Pontiac fever (much milder, flu like, no pneumonia, hot tubs, attacks lotsa ppl)
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pathogenesis of legionella?
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neutros dont work well, resistant to complement, multiplies in macs (prevents phagosome lysosome fusion, reduces oxidative bursts, ribosomes and mito are recruited to phagosome)
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how do you diagnose legionella?
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clinical symptoms of pneumonia with dry or no cough and GI symptoms, culture (specefic media, 3to5 days), urinary antigen test, PCR,
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treatment and prevention for legionella?
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erythromycin, rifampin, newer macrolides, fluoroquinolones, antibiotic must be able to penetrate macriphage. prevent via hyperchlorination of water supply, superheat water, filtration if you got it, need to prevent source of infection bc it causes epidemics...
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describe the diseases caused by Burkholderia species.
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B. pseudomallei and cepacia complex most important. "meliodosis" is uncommon in US, latent and chronic, intracellular, multiple organs infected, includes abscesses, pneumonia, cutaneous infection, sepsis and osteomyelitis, diagnose by culture. B. mallei is a potential bioweapon
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this bac is found in the environment, has lavender to green colonies, resistant to many antibiotics, common nosocomial and immunocompromised infection, less severe than pseudomonas infections
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stentrophomonas maltophilia
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describe acinetobacter.
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baumannii is most common pathogen sp, rod or coccobacilli, nosocomial, sometimes on skin, IV catheters and burn pts get it, less virulent than pseudomonas, fatal infections possible, resistant to many antibiotics
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pseudomonas mnemonics?
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PSEUDO: pneumonia, sepsis, external otitis, UTI, drug use and diabetic osteomyelitis. AERuginosa ia AERobic
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