MISCELLANEOUS GRAM – NEGATIVE BACILLI Flashcards
2 important species under genus Pasteurella
- P multocida and P. canis
General characteristics of P multocida and P. canis
- animal pathogen
- commensal in oropharynx of health animals
- can infect human thru bite, scratches, or shared food
These organisms are the most common organism in human wounds inflicted by bites from cats and dogs
- Pasteurella spp.
specifically P multocida and P. canis
Three general form of disease caused by Pasteurella
- Localized cellulitis and regional lymphadenopathy after animal bite or scratch
- Exacerbation of chronic respiratory tract disease in px w/ underlying pulmonary dysfunction (e.g. asthma)
- Systemic infection in immunocompromised px
Lab diagnosis for Pasteurella
- Grows well on BAP & CAP
- Large “BUTTERY” colonies with MUSTY odor
Treatment for Pasteurella
- Susceptible to penicillin, macrolides, and tetracycline
Morphological characteristic of Bordetella
- extremely small coccobacilli
- simple nutritional requirement
- they are very sensitive and susceptiple to even the slightest toxic substances
These can used to remove toxic substances in culture media when isolating Bordetella
- charcoal, starch, blood, or albumin to absorb toxic substances
4 medically important spp. of Bordetella
- B. pertussis
- B. parapertussis
- B. Bronchiseptica
- B. holmessii
are closely related, differing only in the expression of irulence genes
Bordetella spp that causes the” WHOPPING COUGH” / severe cough disease
- B. pertussis
Bordetella spp that causes the midl form of pertussis
- B. parapertussis
Bordetella spp that causes the respiratory disease of animals (pigs and dogs)
- B. bronchiseptica
Bordetella spp that is an uncommon cause of SEPSIS
- B. holmesii
Bordetella is very contagious since it is an ____________ acquired infection
- AEROSOL
These aids to the bacterial attachement of most bacteria to the cilliated epithelial cells of the respiratory tract
-ADHESINS
RGD motif is a tripeptide amino acid composed of
- Arginine, Glycine and aspartate
responsible for cellular attachement of bacteria
4 bacterial ADHESINS of Bordetella Pertussis
- Filamentous hemagglutinin
- Pertactin
- Pertussis toxin
- Fimbria
B. pertussis toxin that binds lactosylceramide on ciliated respiratory cells
S2
B.pertussis toxin: toxic subunit
S1
B. pertussis toxin that binds phagocytic cells
S3
Adhesin of bordetella that mediate binding in viitro
Fimbria
Charcoal is a common additive in Regan-Lowe medium for B. pertussis , what is it for?
Color reactant
Nutrional additive
Toxin removal
Hemolysin source
- Toxin removal
along with starch, blood, or albumin
What is the best specimen for isolation of B, pertussis?
blood urine bronchoalveolar lavage nasopharyngeal swab sputum
- nasopharyngeal swab
The most infectious phase of the B. pertussis infection. *
Catarrhal
Convalescent
Paroxysmal
Incubation
- Catarrhal
TRACHEAL CYTOTOXIN mode of action
- target ciliated epithelial cells
- impair regeneration of damaged cells by interfering DNA synthesis (disrupt clearance mechanism thus lead to cough)
- IL-1 production (lead to fever)
ADENYLATE CYCLASE TOXIN / HEMOLYSIN mode of action
- activated by CALMODULIN and converse ATP to cAMP , increase respiratory secretion
- inhibit leukocyte function
DERMONECROTIC TOXIN mode of action
- vasoconstriction and tissue destruction
3 phases of B.pertussis infection
- Catarrhal
- Paroxysmal
- Convalescent
Clinical manifestations of Catarrhal phase
- resembles common cold
- classic symptoms
e. g., sneezing, malaise, low-grade fever - the MOST INFECTIOUS phase
Clinical manifestations of Paroxysmal phase
- series of REPETITIVE COUGH followed by inspiratory WHOOP, vomitting and exhaustion
Clinical manifestations of Convalescent phase
- pparoxysms diminished w/ secondary complications
Pentavalent vaccine is composed of
Diphtheria, pertussis, tetanus,hepatitis B and Haemophilus influenzae type b vaccines
Differential Diagnosis for B. pertussis
- Mycoplasma pneumoniae
- Chlamydopphilia pneumoniae
- Legionella pneumophila
Lab Diagnosis for B. pertussis
- sensitive to drying
- inoculate NASOPHARYNGEAL ASPIRATE
- use synthetic fiber sabs not cotton swabs
- fatty acid are toxic to Bp
Specific media for B. pertussis
Regan- Lowe charcoal medium
composed of charcoal, horse blood, glycerol and peptones
Zoonotic pathogens and potential agents of bioterrorism
Francisella & Brucella
Francisella is what type of proteobacteria
Gamma- proteobacteria
Brucella is what type of proteobacteria
Alpha- proteobacteria
Papthogenecity of Francisella
- contains anti-phaogytic capsule
- survive for prolonged period inside macrophages
- inhibits phagosome- lysosome fusion
- obligate intracellular parasite (can grow only inside cell)
Francisella tularensis is transmitted by:
- acquired thru Tick bites
ticks are natural reservoirs of these organism
Which zoonotic bacteria is commonly isolated in dog and cat infections? *
F. tularensis
P. multocida
L. pneumophila
T. gondii
P. multocida or P. canis
Which of the following statements is NOT correct about F. tularensis? *
obligate aerobic and motile
transmitted via deer flies and tciks
requires growth factors like cysteine and thiosulfate
virulence factor is capsule
- obligate aerobic and motile
Clinical disease caused by Francisella tularensis
- TULAREMIA / Rabbit or Tick fever
F. tularensis growth requirement in culture medium
- not possible on gram- staining
- produce B-LACTAMASE
- won’t grow without CYSTEINE
- use CAP or buffered charcoal yeast extract
Francisella has a croos-reactivity reaction with what organism
BRUCELLA
Treatment for Francisella
- Penicillin and cephalosporins are Ineffective ( they produce b-lactamase)
- Streptomycin and gentamicin are effective
4 spp of Genus Brucella
- B. melitensis - goat and sheep
- B.suis - swine reindeer, caribou
- B. abortus - cattle, bison
- B. canis - dog, fox, coyotes
General characteristics of Brucella spp.
- SMOOTH COLONIES with virulence
- Obligate intracellular parasite
- inhibit phagolysosome fusion
- bacteria secrestes protein that induce GRANULOMA formation
This is necessary for the growth Brucella and is often found on animal tissues
- ERYTHRITOL
Clinical disease caused by Brucella
- Brucellosis/ BANGS disease/ UNDULANT fever/ MALTA fever/ ROCK fever