CLS06 - Non-entero GNB

The flashcards below were created by user victimsofadown on FreezingBlue Flashcards.

  1. Why are non-entero GNR medically relevant?
    • Small percentage of clinical isolates
    • difficult to ID
    • Frequent nosocomial agents (immunocomp, trauma introductions)
  2. What is the CDC ID scheme for non-entero GNR?
    • MAC: growth vs no growth
    • Oxidase: + vs -
    • O/F test: oxidative/fermentative/asacchrolytic
    • further testing: motility, nitrate reduction/denitrification, urease production, esculin hydrolysis, indole (using Ehrlich's reagent)
  3. Pseudomonas general (habitat, clinical imp, imp biochem, colony appearance, smell)
    • habitat: common in env, especially water
    • clinical: leading nosocomial agent of resp tract
    • *P. aeruginosa is #1 clinically isolated non-entero GNR
    • biochem: oxidase+
    • colony: pearlescent appearance
    • diff spp secrete diff pigments (P. aeruginosa is pyocyanin [blue-green])
    • (SBA) spreading and flat w/ serrated edges, often B hemolytic
    • *mucoid if taken from CF pt
    • smell: cheap wine
  4. Pseudomonas aeruginosa - associated infections, virulence factors, ID method
    • infections: Opportunistic pathogen (road rash, trauma)
    • associated with CF pts
    • Nosocomial infections (blood, wounds, trauma)
    • swimmer's ear, ear infections, hot-tub folliculitis
    • virulence: intrinsic resistance to many antibiotics
    • Capsule (esp CF pts)
    • motility, endotoxins, exotoxins
    • ID: growth @ 42C
    • carb oxidation+
    • pearlescent colony appearance
    • automated commercial systems
  5. Burkholderia cepacia - habitat, clinical imp, virulence factors, disease, ID characteristics
    • habitat: ubiquitous in env (plants, soil, water)
    • clinical: transmission via direct contact w/ contaminated medical devices
    • can survive disinfectants, detergents, etc
    • virulence factors: intrinsic resistance to many antibiotics
    • elimination in CF pts is rare
    • disease: pneumonia in CF patients (increased severity of disease in death) - fulminate lung disease
    • endocarditis, UTIs, dermatitis, etc (rarely fatal)
    • ID: produces a yellow pigment (SBA and burk. selective agar)
  6. Burkholderia pseudomallei - habitat, transmission, diseases, clinical imp, ID char
    • habitat: soil, streams, rice paddies in Australia/Southeast Asia
    • trans: inhalation or direct contact (trauma)
    • disease: melioidosis (aggressive granulomatous pulmonary disease -> metastatic abscess formation on lungs/viscera -> overwhelming septicemia)
    • pneumonia, orbital cellulitis, etc
    • clinical: bioterrorism agent (mandatory report)
    • ID: grows at 42C, gas from nitrate red+, old potato smell
  7. Acinetobacter baumanii - habitat, clinical imp, disease, ID char, virulence factors
    • habitat: moist env, hospital env
    • clin: nosocomial agent (assoc w/ ventilators, catheters)
    • 2nd most common non-enteric GNR isolate
    • disease: opportunistic pathogen (often involving debilitated pts)
    • endocarditis w/ 22% mortality
    • UTIs, resp tract, wounds, etc
    • ID char: oxidase-, nonmotile, colonies may be tinted purple (false lactose on MAC)
    • can appear as G+ cocci on smear!!!
    • vir: can exhibit resistance to wide range of antibiotics
  8. Stenotropomonas maltophilia - habitat, clin imp, disease, ID char, virulence factors
    • habitat: ubiquitous in water env, soil, plants, urine, resp secretions
    • clin: major nosocomial agent (assoc w/ blood-draw, catheter, IV lines, breathing tubes, CF, transplantation)
    • 3rd most commonly isolated non enteric GNR
    • disease: bacteremia, resp inf, UTIs, wound infections, etc
    • ID: oxidase-, lavender-green pigment (SBA), faint ammonia smell
    • vir: inherent resistance to many antibiotics
  9. TCBS agar - purpose
    • Thiosulfate Citrate Bile Salts agar
    • used for selective siolation of cholera vibrios and Vibrio parahaemolyitics
  10. Campylobacter agars - purpose, types
    • isolation/cultivation of campylobacter jejuni jejuni from human feces
    • *campy is a Diva about growing (very slow, small)
    • campy blood agar: includes antibiotics
    • skirrows agar: slaked horse blood (X-factor), antibiotics
    • campy CSM: columbia base, charcoal, hematin, antibiotics
    • campy CVA: brucella base, defrinated sheep's blood, antibiotics
  11. Vibrio cholerae - habitat, diseases, vir factors, media req, ID, morphology, treatment
    • habitat: brackish/marine water (need salt for growth) (aeromonas is fresh)
    • disease: epidemics/pandemics of cholera
    • V. vulnificus causes fatal septicemia in pts w/ liver disease
    • other vibrio cause gastroent, wound inf
    • vir: cholera toxin (CT)
    • causes "rice water stools" (no blood)
    • EXTENSIVE fluid loss, death without medical intervention
    • *somatic Ag O1 and O139 are indicators of potential virulence
    • media: only collected/tported in Cary-Blair media (others will be toxic)
    • TCBS agar
    • ID: yellow colonies on TCBS agar (normally green)
    • string test+ (compared to Aeromonas)
    • growth in 6.5% NaCl (compared to Aeromonas)
    • ELISA
    • morph: small, straight or CURVED bacilli
    • treat: rehydration, vaccines for non-Us
  12. Aeromonas - habitat, diseases, groupings, media, ID, morph, treatment
    • habitat: fresh water (vibrio is brackish)
    • disease: gastroenteritis, bacteremia, wound infections, endocarditis, pneumonia, conjunctivitis, can lead to complications (HUS and kidney disease)
    • mesophilic group: grow ~body temp, 3 complexes, motile
    • psychrophilic grou: grow @22C, only A. salmonicida, FISH PATHOGEN, nonmotile
    • media: resembles Yersinia on CIN agar (except oxidase+)
    • ID: string test- (compared to Vibrio)
    • no growth in 6.5%NaCl (compared to Vibrio)
    • ELISA
    • morph: single polar flagella
    • treat: treatment for diarrhea not usually needed
    • resistant to some antibiotics
  13. Campylobacter (habitat, spp, transmission, micro app, growth req, disease, treatment, ID, special considerations)
    • habitat: normal flora (GI/repr) in various animals - pathogenic in humans
    • spp: C. jejuni and C. coli are most commonly isolated
    • transmission: contaminated milk, food, water (primarily chicken)
    • micro: very small, curved (gull wings), GNB
    • growth req: microaerophillic AND capnophilic conditions 
    • disease: gastroenteritis (#1 agent worldwide and US), febrile systemic disease, periodontal disease
    • complications following infection include reactive arthritis and Guillain-Barre syndrome (demyelination of nerves)
    • treat: self-limiting
    • no standard for susc. testing
    • IDdarting motility on wetmount
    • small gull-wing faintly staining rods
    • blood and WBCs in stool
    • PCR
    • considerations: special tport media must be used if >2hr delay (special growth reqs)
    • req microaerophilic and capnophilic atmosphere
    • variety of specialized media (to kill other stool bact)
  14. Helicobacter pylori - habitat, motility, similar to?, imp biochem, disease, ID, culture considerations, treatment
    • habitat: inhabits human gastric mucosa (transmission unknown)
    • >50% of adults 60+ infected
    • colonizes mucosal layer, but DOES NOT invade epithelium
    • motility: highly motile
    • similar: originally name Campylobacter due to spiral-shaped morphology
    • biochem: strong urease activity
    • disease: gastritis, ulcers, carcinoma
    • can persist for decades asymptomatically
    • ID: urease test
    • UB test uses radioactively labeled urea (can use biopsy if necessary)
    • EIAs, molecular methods
    • culture: various specialized media (including Thayer-Martin -normally for N. gonnorhea)
    • VERY slow (can take >7days)
    • incubation requires humidity and microaerophillic
    • treat: triple-drug therapy due to frequent relapses and resistance development
  15. BCYE agar
    • Buffered charcoal yeast extract
    • used for isolation of Legionella spp
    • *Ferric pyrophosphate and alpha-ketoglutarate req for Legionella spp
  16. Bordet-Gengou agar (or Regan-Lowe)
    • used for detection/isolation of Bordetella pertussis
    • *initially shiny colonies
    • mostly replaced by PCR
  17. Haemophilus - habitat, micro app, culture req, diseases, ID, virulence factors
    • habitat: normal flora of upper resp tract
    • micro: g- coccobacilli, small
    • culture: requires X and V factor
    • *NOTE - H. parainfluenzae requires only V factor
    • need immediate plating (suscep to drying)
    • disease: H. aegypticus - conjunctivitis
    • H. ducreyi - chancroid (painful) genitul ulcer
    • H. parainfluenzae - endocarditis post dental work (rare)
    • H. influenzae - bronchitis/pneumonia (elderly), sinusitis/otitis media (neonatal), meningitis (IMC)
    • *NOTE - encapsulated strains are more serious, and typed based on capsule Ag
    • H. influenzae type B (HIB) most common
    • ID: MAC neg (will not grow)
    • seen as satellite colonies near Staph on SBA (produces V factor)
    • Horse blood bacitracin agar (HBBA) used to isolate H. influenzae from P. aeruginosa in CF samples
    • agglutination tests, X/V factor discs, porphyrin test
    • vir: resistant to numerous antibiotics
  18. Haemophilus - which spp indicate infection?
    • H. influenzae and H. ducreyi indicate an infection
    • H. aegypticus and H. parainfluenzae could be normal flora
  19. What are the members of the HACEK group?
    • Aggregatibacter aphrophilus (used to be Haemophilus paraphrophilus)
    • Aggregatibacter acinomycetmcomitans (used to be Actinobacillus actinomycetemcomitans)
    • Cardiobacterium hominus
    • Eikenella corrodens
    • Kingella spp
  20. HACEK group - ____robic, habitat, disease
    • all are capnophilic
    • habitat: normal oral flora
    • disease: endocarditis following mouth surgery (opportunistic)
  21. Aggregatibacter aphrophilus - habitat, disease, micro app
    • habit: oral flora (dental plaque)
    • disease: endocarditis
    • micro: small coccobacillus (like Haemophilus) - diff by growth without X/V factors)
    • **HACEK group
  22. Aggregatibacter actinomycetemcomitans - types, habitat, disease, colony morph
    • types: serotypes based on surface polysaccharides
    • hab: normal oral flora
    • disease: endocarditis
    • *associated w/ bites (boxers)
    • colony: adhere to agar, distinctive star shape at center of colonies
    • **HACEK group
  23. Cardiobacterium hominis - habitat, disease, micro app, colony morph
    • habitat: oral flora, GI tract
    • disease: endocarditis
    • gram stain: arrange in "rosettes" or spindles
    • colony: pitting (burrowing) associated w/ agar growth, adhere to agar
    • **HACEK group
  24. Eikenella corrodens - habitat, disease, colony morph
    • habitat: oral cavity commensal
    • disease: endocarditis, bacteremia (least common cause of endocard in HACEK)
    • assoc w/ bites, fights, and diabetics
    • colony: yellow colonies, pitting, strong chlorine odor
    • **HACEK group
  25. Kingella - spp, habitat, disease, micro app, colony morph
    • spp: kingae, dentrificans, oralis
    • habitat: colonize upper resp and Urogen
    • disease: joint/bone infections (pediatric), endocarditis/wound infections
    • micro: square ended bacilli (more than other HACEK), potential chaining
    • colony: multiple types
    • GROWS ON MTM (mistaken for N. gonorrhoeae)
    • **HACEK group
  26. Brucella - transmission, spp, virulence factors, clin imp, imp biochem, disease, culture considerations, treatment
    • trans: ZOONOTIC disease, ingestion of unpasteurized milk, inhalation of aerosolized particles, direct contact w/ infected animals
    • spp: melitensis, abortus, suis, canis
    • vir: intracellular pathogens (phagocytes)
    • clin: possible bioterrorist agent (easily aerosolized, moderate morbidity)
    • biochem: H2S production
    • disease: 3 stages of undulant fever
    • acute - fever, malaise, myalgia... w/in 8 wks
    • subchronic (undulant) - fluctuating fever, arthritis... w/in 1 year
    • chronic: arthritis, chronic fatigue.. 1+ year after
    • localizes in erythritol-rich tissue (placenta = abortions)
    • culture: very slow growth (grow for 3 weeks)
    • requires humidity and slight CO2
    • 5% heated horse/rabbit serum enhances growth
    • treat: 6 week course of M0 penetrating antibiotics to prevent reinfection
  27. Legionella - ___robic, spp, transmission, habitat, disease, preferred spec, culture considerations, ID,
    • strict aerobes
    • spp: 52+ spp (L. pneumophilia - 16 serotypes - is predominant pathogen)
    • transmission: aerosols
    • habitat: ubiquitous in env, aquatic env, AC ducts, plumbing systems, etc
    • can survive extreme ranges of heat (can multiply within certain amoebae)
    • disease: Legionnaire's disease (pneumonia 10-20% fatal, sporadic/endemic/epidemic), Pontiac (respiratory) fever (self-lmiting), would abscesses, endocarditis
    • *mostly IMC, 60+, or heavy smokers
    • spec: sputum > pleural/blood/biopsy
    • deliver within 30 minutes of collection to avoid overgrowth by others
    • culture: STRICTLY AEROBIC
    • 2 plates used - BCYE w/o inhibtory agents and BCYE w/ antibiotics
    • growth in 2-4 weeks
    • ID: ground glass appearance on BCYE ("grainy"), serodiagnosis from ref lab
    • *AST not indicitative of in-vivo response to therapy (not helpful)
  28. Bordetella - habitat, spp, disease, virulence factors, culture considerations, ID, treatment
    • habitat: ONLY INFECTS HUMANS (no reservoir)
    • spp: B pertussis, B. parapertussis
    • disease: pertussuis (whooping cough) 
    • highly contagious via droplets from cough
    • 3 stages...
    • catarrhal - mild cold symptoms
    • paroxysmal - many episodes of violent coughing per day, vomiting, "whooping" sound when air is rapidly inhaled past swollen glottis
    • convalescent - lymphocytosis w/o fever
    • vir: Pertussis toxin (PT) - disrupts cell ability to "call for help" or "receive help" via signals
    • adhesins - attach bacteria to ciliated cells
    • cytotoxin - paralyzes cilia
    • culture: recovery from resp spec requires addition of other factors
    • Bordet-Gengou potato infusion, Regan and Lowe
    • ID: B. parapertussis can grow on MAC (B. pertussis cannot), colonies appear as "drops of mercury"
    • treatment: vaccine available
Card Set:
CLS06 - Non-entero GNB
2016-04-09 04:03:28
CLS06 Non entero GNB
CLS06 - Non-entero GNB
Show Answers: