Title: MYCOBACTERIA CORYNEBACTERIA LEGIONELLA
1 MYCOBACTERIACORYNEBACTERIALEGIONELLA
Faculty Dr. Alvin Fox
2KEYWORDS
- Acid Fast
- Tuberculosis
- M. tuberculosis
- M. avium - M. intracellulare complex
- M. bovis
- M. leprae
- Atypicals
- Tubercle
- PPD
- Tuberculin
- Mycobactin
- Cord factor
- BCG
- Leprosy (Hansen's Disease)
- Runyon groups
- Mycolic acids
- Diphtheria
- C. diphtheriae
- Loeffler's agar
- Tellurite agar
- Metachromatic bodies
- Diphtheria toxin
- Schick test
- Diphtheroids
- Legionella pneumophila
- Legionnaires disease
- Pontiac fever
- Legionella micdadei
- Pittsburg pneumonia
3Mycobacteria
- obligate aerobe
- acid-fast rods
4Mycobacterium tuberculosis
5Tuberculosis (TB, consumption)
- M. tuberculosis
- major human disease
- healthy people
- problems
- association with AIDS
- multiple drug-resistance
6- M. avium- M. intracellulare complex (M. avium)
- non-AIDS
- infection almost never
- AIDS
- major bacterial opportunist
-
- multiple drug-resistance
7 M. bovis
- spread from cattle
- infected cattle are culled
- positive skin test
- rarely seen in US
8M. leprae
- leprosy
- major disease of third world
- rare in US
9Other mycobacteria
10Transmission -tuberculosis
- M. tuberculosis causes disease
- healthy individuals
- transmitted man-man
- airborne droplets
11Mycobacterium tuberculosisin lung
12Pathogenesis of tuberculosis
- infects lung
- distributed within macrophages
- facultative intracellular pathogen
- inhibits phagosome-lysosome fusion
- resists lysosomal enzymes
13Cell-mediated immunity -tuberculosis
- infiltration
- macrophages
- lymphocytes
- granulomas
- tubercules
14Laboratory diagnosis - tuberculosis
- skin testing
- delayed hypersensitivity
- tuberculin
- protein purified derivative, PPD
- X-ray
15Positive skin test -tuberculosis
- indicates exposure to organism
- does not indicate active disease
16- Other minor pathogenesis factors
- tuberculosis
- mycobactin
- siderophore
- cord factor
- damages mitochondria
17Laboratory diagnosis M. tuberculosis
- acid fast bacteria
- sputum
18Laboratory diagnosis M. tuberculosis (culture)
- grows very slowly
- several weeks
- non-pigmented colonies
- niacin production
- differentiates from other mycobacteria
19Tuberculosis
- polymerase chain amplification
- rapid diagnosis
20Antibotic treatment - tuberculosis
- extensive time periods (e.g. 9 months)
- organism grows slowly, or dormant
- two or more antibiotics
- e.g. rifampin and isoniazid
- resistance minimized
21Vaccination
- BCG vaccine
- an attenuated strain of M. bovis
- not effective
- in US,
- incidence is low
- vaccination not practiced
- immunization interferes with diagnosis
22Mycobacterium leprae
23Leprosy (Hansen's Disease)
- M. leprae
- causative agent
- chronic disease
- disfigurement
- rarely seen in the U.S.
- common in third world
- millions of cases
- infects the skin
- low temperature
24- ulcers, resorption of bone
- worsened from careless use of hands (nerve damage)
25Leprosy
- tuberculoid
- few organisms
- active cell-mediated immunity
- lepromatous
- immunosuppression
- few organisms
26Production of M. leprae antigens and
pathogenesis studies
- in vitro
- unculturable
- in vivo growth
- low temperature
- armadillo
- mouse footpad
27Leprosy
- lepromin
- skin testing
- acid-fast stains
- skin biopsies
- clinical picture
28Atypicals - mycobacteria (including M. avium)
other than M. tuberculosis and M. leprae
- infect compromised host
- not transmitted man -man
- healthy people
29Atypical mycobacterial diseases
- tuberculosis-like
- leprosy-like
30Mycobacterium avium and AIDS
31- M. avium is much less virulent than M.
tuberculosis - does not infect healthy people
- infects AIDS patients
- M. avium infects
- when CD4 count greatly decreased
- M. tuberculosis infection
- infects healthy people
- infects AIDS patients
- earlier stage of disease
- more systemic
32Clinical features with AIDS
- systemic disease (versus pulmonary)
- greater in AIDS
- lesions often lepromatous
33 Antibiotic therapy
- selected primarily for M. tuberculosis
- if M. avium suspected other antibiotics included
34Other atypicals
- pigmented or not
- pigmentation
- light
- dark
- growth
- fast
- slow
35 Mycobacterial species identification
- cellular fatty acid profiles
- mycolic acid profiles
- genetic markers
36Mycolic acids
- mycobacteria
- longest chain length
- strongly acid fast
- nocardia
- intermediate chain length
- weakly acid fast
- corynebacteria
- shortest chain length
- not acid fast
37Corynebacterium diphtheriae
38Corynebacterium diphtheriae
- Gram positive
- strict aerobe
- pleomorphic
39Diphtheria
- infection
- upper respiratory tract (pharynx)
- pseudomembrane
- chocking
- bacteria do not spread systemically
-
- .
40This child has diphtheria resulting in a thick
gray coating over back of throat. This coating
can eventually expand down through airway and,
if not treated, the child could die from
suffocation CDC
41Diptheria toxin
- spreads
- systemic and fatal injury
42Diphtheria toxin
- B binds to host cell
- A inhibits protein synthesis
- ADP-ribose moiety (NADH) attaches
- rare amino acid, diphthamide
- elongation factor 2 inhibited
43Treatment
44Immunization against diphtheria (infant)
- disease vanished in US
- without immunization will return
- toxoid ( pertussis and tetanus) DPT
- neutralizing antibodies
- colonization not inhibited
- found in normal flora
45Testing immunity
46Diphtheria toxin
- coded by bacteriophage tox gene
- not synthesized if iron present
- iron-repressor complex forms
- inhibits expression of tox gene
47 Identification - C. diphtheriae
- growth Loeffler's medium
- stain for polyphosphate granules
- metachromatic
- polyphosphate granules (pink) cell (blue)
- tellurite agar
- reduction by bacteria
- tellurium precipitation
- black colonies
48Exotoxin production
49- C. diphtheriae should not be confused with
- diphtheroids
- other corynebacteria
- propionibacteria
50 Legionella pneumophila
51Legionella pneumophila
- Legionnaire's disease.
- pneumonia
- fatal if not treated
- erythromycin
- Pontiac fever
- flu-like
- milder
- self-limiting
- myalgia (muscle pain)
- no pneumonia
52Transmission
- contaminated air
- infected water supply
- not spread person-person
53Legionnaires disease
- small epidemics
- healthy people
- more frequently
- sick or elderly
- hospitals
- immunocompromised
54Identifcation of Legionella
- no growth conventional agar
- e.g. sheep blood agar
- media must contain
- iron
- cysteine
- e.g. charcoal yeast extract agar
- isolation clinical specimens
- poor
55Legionella pneumophila
- stains poorly
- Gram negative rod
56Legionella pneumophia
- environmental reservoir
- pools of stagnant water
- hot water towers
- air conditioning systems
- intracellular growth, protozoa
- facultative intracellular pathogen
- humans
57Legionnaires disease -indoor air quality
- contaminated buildings
- air conditioning system
- water supply
58Legionellae
- Legionella pneumophila
- several serogroups
- most infections, serogroup 1
- Legionella micdadei
- Pittsburg pneumonia
- Other Legionella
- occasional disease
- legionellosis
-
59Identification of Legionella
- fatty acid profiling
- DNA-DNA hybridization
- 16S rRNA sequence
- Detection of antigen in urine