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Microbiology- Bacteriology
Bordetella, Haemophilis, Legionella (T Pierce)
38
Medical
Professional
09/18/2009

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Cards

Term
What do bordetella, haemophilis, Legionella have in common
Definition
  • aerobic gram negative rods
  • resp. disease with wide range of clinical manifestations
Term
Bordetella (structure)
Definition
  • nonmotile
  • aerobic gram negative rod/coccobacilli
Term
cause of whooping cough
Definition

bordetella pertussis

Term
cause of resp./genital tract disease
Definition
Haemophilis
Term
cause of Legionnairs disease
Definition
Legionella pneumpohilia
Term
epidemiology of Bordetella pertussis
Definition
  • exclussive human pathogen
  • spread by aerosolized dropletes (cough)
  • 20-30% of adults with prolonged cough may have pertusus
  • wannin post vaccine immunity, so adults/adolescents are at risk for disease
  • 90% of cases found in developing world
Term
DPT vaccine effect on epidemiology of Bordetella pertussis
Definition
  • vaccine has changed epidemiology
    • prevaccine
      • seen in age 1-5 (women surviving infection pass on to kids)
    • post
      • moms dont give passive immunity
      • immunity wanes after 12 yrs
Term
pathogenesis of Bordetalla pertussis
Definition
  • exposure thorugh inhalation of aerosolized bacteria (infected human reservoir)
  • attach to ciliated epithelial cells of bronchial tree
  • bacteral prolif.
  • VFs produce
    • localized tissue damage
    • systemic toxicity
Term
VF's of pertusis
Definition
  • filamentaous Hb- block neutrophil phagocytosis, help bind to resp. ciliia
  • pertussis toxin (can be local and systemic)
  • pili and peractitin- attachment of bacteria to epithelium

MAINLY BINDING/ATTACHMENT

Term
stages of clinical manifestation of pertussis
Definition
  • stage one: incubation period (7-21 days); asymptomatic
    • bacteria attach, prolif on ciliated epithelium
  • stage 2: catarrhal stage (1-2 wks); most contagious
    • symptoms- rhinitis, malaise, low grade fever, sjneezing, anorexia, increase WBC
    • peak bacteria prod., disease not recognized
  • stage 3: paroxysmal stage (2-4 wks)- 40 to 50 paroxysms/day
    • symptoms- repetitive cough with whooping (expir. cough with inspir. gasp), vomit, exhaustion
    • extrude ciliated epithel. cells impair mucus clearance, lead to mucus plug airway
  • stage 4- convulescent stage (improved paroxysmal cough)
    • development of secondary sysmptoms including pneumonia (main cause of mortality), seizures, enxephalopathy
Term
complications of pertussis
Definition
  • rare encephalopathy and seizures
  • paroxysomal cough can increase intrathoracic and intraabdominal pressure cause:
    • subconj. hemorrhage
    • truncal hemorrhage
    • epistaxis
    • pneumothorax
    • rectal prolapse
Term
Paraxysomal cough can lead to what
Definition
frenal ulcer (traumatic ulcer because of tongue protrudin against sharp teeth during coughing)
Term
Radiograph of pneumonia due to pertusus? cause of pneumonia
Definition
  • Xray- collapse of lung resulting from mucus plugging of smaller bronchi and bronchioles
  • cause- aspiration durin cough, impaired sec.

 

MAIN CAUSE OF MORTALITY

Term
diagnosis of pertussis
Definition
  • difficult
    • organisms decrease as symptoms increase
    • clinical clue- cough 2 wks
  • culture Bordet Gengou media (up to 2-7 days)
  • direct flurescent Ab (DFA)
  • serology- rise between acute and convalescent sera
Term
Tx, prevention of pertussis
Definition
  • supportive therapy (ex: if pneumonia, antibiotics with oxygen therapy)
  • current vaccine
Term
Haemophilius influenzae growth requirements
Definition
  • aerobic growth requires two supplements X factor (hemin) and V factor (NAD)
Term
HIB vaccine (function)
Definition
  • made against type B capusule producin strains (this strain assoc. with most invasive infections)
    • have six Ag distinct capsular types (A to F)
    • strains without capsule called nontypeable
Term
Appearance of H influenzae on gram stain
Definition
small, pleomorphic, pale staining gram negative bacilli
Term
epidemiology of H influenzae
Definition
  • humans only natural host
  • transmission via contact w/secretions or airborne droplets
  • since advent of widespread vaccinations, H influenzea infections most likely to occur:
    • nonencapsulated forms, (A-C, F)
    • type B infection if nonimmune children or elderly with waning immunity
  • risk factors
    • HIV/AIDS
    • sickle cell disease
    • splenoectomy
    • chronic lung disease
    • smoking
    • malignancy
    • pregnancy
    • alcoholism
Term
VF's of H influenza
Definition
  • capsule- inhibit opsonization, intracell. killing
  • LPS
    • initiate invasive disease
    • endotoxin like activity, tissue damage
    • facilitate survival on mucosal surface (nasopharynx)
  • outer membrane proteins (OMP)
    • contribute to Fe scavengin and bindin required for organism survival
  • fimbriae
    • on bacterial surface
    • enhance adherance
    • present in typeable and nontypable
Term
pathogen. of H influenzae
Definition
  • humoral immunity
    • protective Ab;'s opsonize bacteria
    • increase reisk if functional asplenia or splenomegally
  • complement (susceptible if def. in C2, C3)
Term
clincial syndromes of H influenzae
Definition
  • meningitis
  • epiglotis
  • otitis media, sinusitis (URT)
  • pneumonia (LRT
  • arthritis
Term
mejningitis of H influenza
Definition
  • occurs after bacteremic spread of organism from nasopharynx
  • assoc. with trauma, neurourgery, CSF leak or paranasal sinusitis
Term
epiglotitis with H influenza
Definition
  • a life threatening emergency with cellulitis and swelling of supraglottic tissues
  • presentation
    • pharyngitis, fever
    • drooling, difficulty swallowing and breathin
    • may progress rapidly to complete airway obstructiona d death
Term
diagnosis of H influenze epiglottitis
Definition
  • lateral neck radiograph will show thumbprint sign
  • cherry red epiglottis
Term
Who is at risk of otitis/sinusitis and pneumonia from H influenzae
Definition
  • most common cause of ottits media in young children
  • occur in immunocompromised, chronic lung disease
    • exacerbation of bronchitis
    • pneumonia- lobar consolidation, effusions/empyema
Term
arthritis from H influenzae
Definition
  • bacteremic spread to single large joins
  • usually on immmunocomp. or with previously damaged joints
Term
diagnosis of H influenza
Definition
  • blood cultures for meningitis, epiglottitits, cellulitis, arthritis, pneumonia
  • supplement media (X and V factor, chocolate agara)
  • Ag detection ELISA (urine, CSF)
Term
treatment of H influenzae
Definition
  • serious infections always should be given IV with epiglottitis and meningtis
Term
prevention of H influenzae
Definition
  • Hib vaccine substantially decreases incidence (98% effective)
  • chemoprophylaxis with Rifampin
Term
H ducreyi (chancroid cause) (clinical manifestations) (description of appearance)
Definition
  • STD
  • cause of genital ulcers in Asia and Africa, and major contributer to transmission of HIV
  • tender papule with erythematous base onthe geintal and perianal area
  • lesion ulcerates and is painful with suppurative inguinal lymphadenopathy
Term
Legionella pneumophilia (morphology, what they cause)
Definition
  • slender, plemorphic, obligately aerobic gram negative bacilli
  • seasonal
  • 90% of cases of disase caused by this bacteria (serogroup 1 most common)
  • use charcoal yeast enriched media
  • nutritionally fastidious
Term
epidemiology of L. pneumophila
Definition
  • fresh water (lakes, streams)
  • most epidemic in summer, fall
  • humans are accidental hosts
  • optimal for symbiotic microorganisms
  • environmental spread through water distrubution
    • showers
    • humidifiers
    • resp. therapy equipment
    • evaporative cooling towers of AC symptoms
    • microaspiration during and after ingestion of contaminated water/ice
Term
pathogenesis of Legionella pneumophila
Definition
  1. pulm. alveolar macrophages engulf bacteria
  2. no intracellular killing
    • oxidative and nonoxidative intracellular killing mech. are inh.
    • blunted or absent resp. burts with release of microbial oxygen derivatives
    • no acidification of phagosome by lysosome to expose bacteria to toxic lysosomal contents
  3. multiplies within specialized endosome and produce cytotoxins
  4. macrophage killed and new bacter released and infect other macrophages

Host defense via NK and cytotoxic T cells lyse infected macrophages to end cycle while humoral immunity increases uptake of bacterial into neutrophils where it cannot replicate

Term
clinical manifestion of L pneumonphila
Definition
  • Pontiac fever
  • Legionellosis
    • febrile systemic illness with pneumonia (another "atypical" pneumonia)
  • pulm. infiltrates- rapid progress of alveolar infiltrates of multilobar consolidation
  • resp. deterioration, multisystem failure and DIC
  • mortality 15-20%
  • pathology
    • intense inflam. changes present in alveoli, alveolar ducts, bronchioles, alveolar septa
  • complications- pleuritis, pleural empyema, pericarditis, cavitary lung disease/abscesses
  • extrapulm. legionellosis
    • occurs in immunocompromised
    • occurs by bacteremic spread
Term
diagnosis of L pneumophilia
Definition
  • high clinical suspicion required
  • culture in enriched media- buffer charcoal yeast extract agar
  • urine Ag- enzyme immunoassay detects serogroup 1 Ag
Term
treatment of L pneumophila
Definition
  • Ab's must have high intracellular concentrations to be effective
  • NEED HIGH CLINICAL SUSPICION
Term
prevention and surveilance of L pneumophila
Definition
  • routine envir. culturing of hospital envir. sources only on discovery of cases
  • routine envir. culturing of hospitals performing organ and bone marrow transplants
  • not contagious- isolation precautions not required
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