Gram- Rods Causing Respiratory Disease, Zoonotic, Opportunisitc Flashcards
what is the morphology of Haemophilus influenzae and what are its special growth requirements?
slender, pleiomorphic Gram- rods
grow on chocolate agar only - require NAD and hemin (found in RBC)
where does Haemophilus influenzae (Gram- rod) colonize, how does it spread, and what are its virulence factors (3)?
only infects humans
unencapsulated/non pathogenic colonizes upper respiratory tract
pathogenic spread via respiratory route, contain:
1. capsule
2. IgA protease
3. iron acquisition mechanisms
may spread locally from URT to middle ear (otitis media), sinuses (sinusitis), and lungs (pneumonia)… can also cause epiglottitis, meningitis, septic arthritis
what is the vaccine for Haemophilus influenzae? (Gram- rod)
Hib conjugate vaccine: capsular polysaccharide conjugated to diphtheria toxin
given to children beginning 2 months of age
25% of Haemophilus influenzae (Gram- rod) produce beta-lactamase and therefore are resistant to ampicillin, but essentially all isolates are susceptible to 3rd generation ______
cephalosporins (cefotaxime)
what bacteria does this describe?
- Gram- rod
- causes respiratory infection
- only colonizes/infects humans
- can only survive in environment for short periods
- produces small colonies on blood agar
- best diagnosed with NAAT (PCR)
Bordetella pertussis
how does Bordetella pertussis (Gram- rod) spread, and what illness does it cause?
spreads via respiratory route (2 week incubation), highly infectious
causes cold-like prodrome followed by “whooping” cough
convalescence is slow (4-6 weeks)
what are 3 adhesins important for Bordetella pertussis (Gram- rod) infection?
adhesins promote attachment and prevent phagocytic clearance
- filamentous hemagglutinin: binds integrins on ciliated epithelial cells
- fimbriae: undergo phase variation
- BrkA protein: complement resistance
what are 3 important toxins for virulence of Bordetella pertussis (Gram- rod)?
- tracheal cytotoxin: stimulates IL-1 mediates killing of ciliated epithelial cells (which it binds to)
- adenylate cyclase toxin: inhibits phagocyte function
- pertussis toxin: systemic effects (lymphocytosis, sensitization to histamine, enhanced insulin secretion)
which bacterial toxin causes lymphocytosis, which is an atypical finding for bacterial infection?
(typically bacterial infections cause granulocytosis)
Pertussis toxin (of Bordetella pertussis, Gram- rod): causes systemic effects - lymphocytosis, sensitization to histamine, insulin secretion
[remember that Bordetella pertussis also produces tracheal cytotoxin and adneylate cyclase toxin]
what vaccine is available for Bordetella pertussis (Gram- rod)?
DTwP: Diptheria, Tetanus, whole cell Pertussis (3 component vaccine)
replaced by DTaP: Diptheria, Tetanus, acellular Pertussis
acellular component includes virulence factors (pertussis toxin)
what bacteria does this describe?
- Gram- rod
- highly fastidious
- causes respiratory infection
- acquired from environmental source (water)
- mild form of disease is termed Pontiac fever
Legionella pneumophila
requires BCYE agar: buffer, charcoal, yeast extract, iron, cysteine, antibiotics
what is the primary diagnostic tool for Legionella pneumophila (Gram- rod) infection?
urine antigen test (Serotype 1 infection)
explain why it makes sense that Legionella pneumophila (Gram- rod) is very fastidious?
natural habitat is water, multiplies in amoebae (protozoan) host —> typically, intracelular bacteria are fastidious because they require host nutrients
in humans, multiples in macrophages and blacks phagosome/lysosome fusion
all zoonotic bacteria are Gram ____ and shaped as ____ or ____
all zoonotic bacteria are small Gram- rods or coccobacilli
little or no human to human transmission
may require non-standard antibiotics, some are highly virulent, risk for bioterrorism
describe the source of Brucella spp. (species) and the illness it causes
small Gram- coccobacillus (zoonotic), from livestock/unpasteurized dairy
—> systemic febrile illness
*significant threat to laboratory workers
describe the source of Pasteurella multocida and the illness it causes
small Gram- coccobacillus (zoonotic), normal oral flora of domestic animals - infection associated with animal bites
—> rapidly progressive soft tissue infection, can disseminate widely
describe the source of Francisella tularensis and the illness it causes
small Gram- coccobacillus (zoonotic), transmitted from wild animals (rabbits) via direct contact or insect vector
low infectious dose (3 organisms), high risk to lab workers, but little to no human to human contact
—> ulceroglandular (ulcer and lymphadenopathy), oculoglandular, oral/pharyngeal (contaminated food/water), respiratory infection (aerosol inhalation)
what was the cause of bubonic plague? how is this bacteria transmitted?
Yersinia pestis: zoonotic Gram- rod
transmitted from rodent to human via flea bite
—> causes enlarged, ulcerated lymph nodes (effacement of lymph node, architecture destroyed)
what special stain is used for Yersinia pestis (zoonotic Gram-)?
Wayson stain - causes “safety pin” appearance due to bipolar staining of bacteria
what kind of bacteria is Pseudomonas aeruginosa?
Gram- rod with polar flagella, opportunistic
ubiquitous in environment, creates biofilms
what bacteria does this describe?
- Gram- rod with polar flagella
- opportunistic and ubiquitous
- obligate oxidizer
- no acids from sugars on test media
- many isolates produces siderophores (pyoverdin)
Pseudomonas aeruginosa - produces biofilms
has many virulence factors: extracellular polysaccharide, pili, LPS, extracellular enzymes, Exotoxin A, Type III secretion system
what kind of disease does Pseudomonas aeruginosa cause?
Gram- rod with polar flagella, opportunistic and ubiquitous
—> nosocomial infections (burn patients, intubated patients), otitis externa, hot tub foliculitis, chronic respiratory infection in cystic fibrosis patients
which of these is most likely to infect blood products, given that it grows at low temperature?
a. Campylobacter jejuni
b. Yersinia enterocolitica
c. Shigella boydii
d. enteropathogenic E. coli
b. Yersinia enterocolitica: type of enteropathogenic Yersinia (as is Y. pseudotuberculosis)
travels from intestine to local lymph nodes
uses Type III system to inhibit phagocytosis, causes painful inflammation of lymph nodes
which of these is a halophile that can cause diarrhea from eating raw fish or shellfish?
a. Vibrios vulnificus
b. Vibrio cholerae
c. Enterotoxigenic E. coli
d. Enteropathogenic E. coli
a. Vibrios vulnificus (also V. parahaemolytics): non-cholera Vibrios, common in natural waters, cause wound/soft tissue infections
remember that halophile = requires NaCl for culture
grows on TCBS medium (thiosulfate-citrate-bile salts)
Which of these zoonotic bacteria is most likely to be found in unpasteurized dairy?
a. Pasteurella multocida
b. Brucella spp. (species)
c. Francisella tularensis
d. Yersinia pestis
b. Brucella spp. —> systemic febrile illness
Which of these zoonotic bacteria is most to be acquired from domestic animals?
a. Pasteurella multocida
b. Brucella spp. (species)
c. Francisella tularensis
d. Yersinia pestis
a. Pasteurella multocida —> rapidly progressive soft tissue infection
Which of these zoonotic bacteria is most likely to be transmitted via an insect vector?
a. Pasteurella multocida
b. Brucella spp. (species)
c. Francisella tularensis
c. Francisella tularensis - transmitted from wild animals (esp. rabbits) to humans via direct contact or insect vector
—> ulceroglandular, oculoglandular, oral/pharyngeal, repository illness
