Extracellular Bacterial Pathogens Part 2 – Flashcards
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| P. aeruginosa |
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| major opportunistic pathogen; follows heavy antibiotic use and foreign object placement |
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| P. aeruginosa |
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| ventilator-associated pneumonia |
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| Non-fermentative rods |
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| Pseudomonas, Burkholderia, and Stenotrophomonas |
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| P. aeruginosa |
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| aerobic, non-fermentative, grows on bile salts, oxidase positive, pyocyanin positive |
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| P. aeruginosa |
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| grape Koolaid smell |
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| virulence factors of P. aeruginosa |
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| type 3 secretion, hemolysins, proteases, exotoxin A, alginate for biofilm formation, pyoverdin, pyocyanin |
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| multi-drug resistant P. aeruginosa |
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| mutation of porin and beta lactamases |
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| clinical diseases of P. aeruginosa |
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| hot tub dermatitis, swimmer's ear, endocarditis in IV drug users, eye infections with contact use |
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| nocosomial Pseudomonas |
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| ventilator associated pneumonia, IV line sepsis, UTIs |
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| abnormal P. aeruginosa infection |
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| malignant swimmer's ear |
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| abnormal P. aeruginosa |
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| bacteremia in CF patients |
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| abnormal P. aeruginosa |
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| ecthyma gangrenosum |
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| abnormal P. aeruginosa |
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| bacteremia in burn patients and immunocompromised/neutropenics |
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| CF patients experience: |
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| chronic P. aeruginosa infections |
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| pathogenesis for chronic P. aeruginosa infection |
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| early airway colonization with pili and flagellum, binding to mucus, eventual loss of O side chains/flagellum/pili, upregulation of alginate, biofilm formation |
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| P. aeruginosa treatment |
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| aminoglycoside + anti-bacteria-specific beta lactam |
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| Burkholderia cepacia |
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| like Pseudomonas, respiratory infections and septicemia, important in immunocompromised |
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| steno superbug |
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| very antibiotic resistant, pneumonia and bacteremia, occurs in patients undergoing broad spectrum treatment |
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| Acinetobacter |
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| nocosomial pneumonia, septicemia, soft tissue infection |
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| enterics |
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| gram - rods, rapid growth, oxidase negative |
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| enterics |
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| >30% septicemias, 70% UTIs, and most of gastroenteritis |
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| surface antigens of enteric pathogens |
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| K (capsule), O polysaccharide, H (flagella), Vi |
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| enteric pathogenesis and immunity |
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| K and H variations, plasmid allows antibiotic resistance, Type 3 secretion, hydrophilic capsule, endotoxic lipid A |
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| E. coli |
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| abundant in GI tract, normal flora, causes sepsis/neonatal meningitis/gastroenteritis/UTI |
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| E. coli |
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| adhesins, Shiga toxins, heat stable toxins, heat labile toxins, hemolysins |
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| E. coli |
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| most common cause of community-acquired gram negative bacteremia |
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| Enterobacter sp. |
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| most common cause of ICU-acquired gram negative bacteremia |
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| UPEC |
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| specialized pili on E. coli causes more virulent UTI |
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| "honeymoon cystitis" |
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| E. coli UTI w/ new partner |
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| prevention/treatment of E. coli UTI |
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| trimethoprim, tannin from cranberries and blueberries to block adhesion, good hygiene |
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| 2nd most common cause of neonatal meningitis behind group B strep |
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| E. coli w/ K-1 capsular protein |
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| 5 groups of E. coli strains |
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| enteropathogenic (EPEC), enterotoxigenic (ETEC), enterohemorrhagic (EHEC), enteroinvasive (EIEC), and enteroaggregative (EAEC) |
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| EPEC |
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| infant diarrhea in developing countries, 2-6d incubation, watery diarrhea, dehydration is deadly |
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| EPEC |
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| injects its own receptor (Tir) for intimin, pedestal formation |
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| EHEC |
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| "hamburger disease," 0157:H7, <100 can cause disease, expresses Shiga-like toxins |
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| EHEC |
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| hemorrhagic colitis, 3-4d incubation, watery diarrhea w/ vomiting, complication is hemolytic uremic syndrome |
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| hemolytic uremic syndrome |
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| most common cause of acute renal failure in children, also causes hemolytic anemia and thrombocytopenia |
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| EHEC |
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| treatment is supportive, antibiotics not suggested, suspected in patients with acute bloody diarrhea w/o fever |
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| ETEC |
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| traveler's diarrhea, high ID50 |
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| ETEC |
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| diarrhea for 3-4d after 1-2d incubation, heat labile toxins LT-1 and 2, heat stable toxins STa and STb |
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| EIEC |
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| Pinv genes on plasmid, invades and destroys colonic epithelium, dystentery-like syndrome w/ bloody mucoid stools, cramps/fever for 1 week |
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| EAEC |
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| mediated by bundle-forming fimbriae, causes persistent diarrhea and possibly growth retardation |
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| E. coli |
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| lactose fermenter, grows green on EMB agar |
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| E. coli treatment |
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| fluoroquinolone guided by susceptibility testing |
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| Shigella |
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| non-motile, does not ferment lactose, severe invasive disease, low ID50 |
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| four species of Shigella |
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| S. sonnei, S. flexneri, S. dysenteriae, S. boydii |
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| Shigella |
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| considered pediatric disease, humans are only reservoir, fecal contamination |
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| Shigella |
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| IpaD adhesin, invasion plasmid |
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| shiga toxin |
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| like ricin toxin, cleaves 28S rRNA and inhibits protein synthesis |
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| shigellosis |
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| small volume diarrhea, cramps, fever, vomiting, blood/mucus in stools, incubation 1-7d, associated w/ rectal bleeding and mucosal ulceration |
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| shigellosis diagnosis |
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| leukocytes in feces and stool culture |
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| shigellosis treatment |
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| fluoroquinolones and then susceptibility is tested, no vaccine available |
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| Salmonella |
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| motile, does not ferment lactose, produces H2S |
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| 3 species of Salmonella recognized |
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| S. typhi, S. typhimurium, S. enteritidis |
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| Salmonella pathogenesis factors |
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| type 3 secretion, SPI-1 and 2, ruffling of host cell membranes, resist stomach acid and phagocytosis |
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| enteritis |
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| 3rd most commonly reported "food poisoning," major cause of human gastroenteritis, self-limiting, antibiotics not recommended |
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| typhoid fever |
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| humans are only reservoir, fecal-oral route, low infection dose |
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| S. typhi |
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| cause of typhoid fever |
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| typhoid fever |
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| rising (step-wise) fever, bacteremia, abdominal pain and rash in week 2, perotinitis/secondary bacteremia/hepatosplenomegaly in week 3 |
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| S. typhi |
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| treated with fluoroquinolones and chloramphenicol, 2 vaccines available |
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| Klebsiella |
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| non-motile, lactose-fermenting, prominent capsule w/ mucoid appearance |
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| Klebsiella |
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| thick bloody sputum w/ currant jelly appearance, primary lobar pneumonia, higher risk for alcoholics w/ compromised pulmonary function |
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| Enterobacter |
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| expended spectrum beta lactamase, capable of inactivating cephalosporins and monobactams |
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| Proteus |
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| UTIs, kidney infections, kidney stones, has urease |
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| Serratia |
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| nocosomial pneumonia |
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| Yersinia |
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| siderophilic, entercolitica and pseudotuberculosis spp. cause gastroenteritis |
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| Y. pestis |
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| called Sylvatic plague in modern times, zoonotic disease, high mortality w/ 3 major pandemics |
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| Y. pestis pathogenesis |
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| Yop proteins, type 3 secretion system, antiphagocytic capsule, plasminogen activating protease, serum resistant factor |
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| Y. pestis |
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| bipolar staining |
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| Y. pestis treatment |
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| tetracycline or streptomycin, isolation required until clear |
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| Y. pestis prevention |
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| safe handling of rodents, vaccine exists but is no longer available |
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| anaerobic gram negative rods |
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| Bacteroides fragilis, Prevotella, Prophromonas, Fusobacterium |
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| Clostridium |
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| anaerobic gram positive, spore-forming |
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| Peptostreptococcus |
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| gram positive anaerobic, non spore-forming, cocci |
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| Propionibacterium acnes and Actinomyces |
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| gram positive rods, anaerobic, non spore-forming |
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| strict anaerobes |
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| PO2 < 0.5%, lack superoxide dismutase |
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| anaerobes |
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| outnumber aerobes 5:1, found in GI tract, nasal passages, vagina, cervix, mouth |
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| Bacteroides fragilis |
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| endogenous anaerobic pathogen, abdominal abscesses and bacteremia, BFT enzyme, organic acid production causes foul smell in wound |
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| B. fragilis |
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| resistant to kanamycin, vancomycin, and colistin |
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| B. fragilis |
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| treatment required: metronidazole + surgery + antibiotics for gram negative infection when infection is mixed |
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| Actinomyces israelii |
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| filamentous bacteria, not acid-fast, gram positive rods, sinus tract abscesses, form sulfur granules |
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| peptostreptococcus |
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| OBGYN infections, aspiration pneumonia, wound abscesses, brain abscesses, chronic otitis media |
