Lecture 18 - Respiratory Bacteriology 3 Flashcards
describe streptococcus
gram-positive, non-motile, faculative cocci
what is Lancefield grouping
classification system for catalase -, gram + cocci based on specific C substance in the cell wall
what are the 3 types of hemolysis
- alpha
- beta
- gamma
describe alpha hemolysis
oxidize iron in RBCs to biliverdin (green color)
describe beta hemolysis
complete rupture/lysis of RBCs by streptolysin
describe gamma hemolysis
no hemolysis
what are the 2 ways streptococcus can be classified
- antigenic structures (cell wall or protein)
- sequence typing
why do some species of streptococcus produce capsules
for protection from phagocytosis
what is a streptococcus capsule composed of
hyaluronic acid (group A)
what adhesions are used in streptococcus spp.
- M protein (microfold)
- fimbriae
- pilli
what toxins are produced by streptococcus spp. give their jobs
- streptolysin-O - attack leukocytes, platelets, etc
- streptolysin-S - less toxic
- streptokinase - cleave C3 via fibrinolysin activation
- DNase
- hyaluronidase - tissue invasion through breakdown
what is the pathogenesis of Strep. pyogenes
*only species in Lancefield Group A
*mostly human pathogen
M protein (major virulence) - creates self-antigen attacks
T protein
Erythrogenic toxins (SPE A, B, and C)
T/F: host immunity against GAS is high specific to M protein
TRUE
can you treat GAS (strep. pyogenes) with penicillin or is there resistance?
Yes; low incidence of resistance
describe strep. equi. what common diseases are caused by this bacteria?
Lancefield group C, B hemolysis
strangles, purpura hemorrhagica
what are the virulence factors of strep. equi
- M protein (antiphagocytic)
- cytotoxins (damage phagocytic cells)
what is strangles
contagious upper resp disease where abscess forms in ln which can compress nerve and rupture into guttural pouch
what is purpura hemorrhagica
type III sensitivity following infection or vaccination of S. equi due to Ab-M protein complex deposition
T/F: Strep. equi mostly affects horses
TRUE
describe strep. suis
Lancefield group D; 35 capsular types; type 2 associated with disease
what are the virulence factors of strep. suis
- muramidase-released protein
- extracellular protein factor
- suilysin
T/F: strep. suis is NOT zoonotic
FALSE
strep suis in humans is…
toxic shock syndrome: septicemia with secondary inflammation
describe the morpholgy of rhodococcus equi
large, gram +, short rod to cocci that creates distinct mucoid colonies on cultures
T/F: R. equi is resistant in the environment with long survival rate
TRUE
what antigens are produced by R. equi
- 7 capsular antigens
- virulence-associated protein A
what does virulence-associated protein A do
survival within macrophages by preventing phagosome-lysosome fusion
what are the clinical diseases of R. equi in horses
- pyogranulomatous bronchopneumonia in foal
- visceral abscess or -itis
what are the clinical diseases of R. equi in swine
lymphadenitis
detection of ____ relies on PCR
mycoplasma
what are the 5 mycoplasma virulence factors
- antigenic shift
- agglutinates
- hemolysin
- immunosuppression
- toxins
T/F: mycoplasma disease is typically associated with epithelial surfaces
FALSE -mucosal
what is the cause of contagious bovine pleuropneumoniae (CBPP)
mycoplasma mycoides
what is the transmission and pathology of CBPP
transmission: aerosol and inhalation
pathology: lesions and interlobular septa thickened by fibrinous exudate and enlarged ln
what does Mycoplasma bovis cause
- pneumonia
- otitis
- mastitis
how is mycoplasma bovis transmitted
- inhalation
- vertical (mammary gland)
what is Mycoplasma dispar associated with
respiratory disease
what is the predisposing agent for infectious bovine keratoconjunctivitis (pink eye)
mycoplasma bovoculi
what is the most economically impactful mycoplasma in goats? what does it cause?
mycoplasma capricolum - contagious caprine pleuropneumoniae
what is the main virulence factor of M. capricolum
capsular protein
T/F: M. capricolum causes systemic disease in goats
TRUE
what causes chronic pneumonia is small ruminants
mycoplasma ovipneumoniae
what are two environmental predisposing factors for M. ovipneumoniae
- housing management
- ventilation
what can be transmitted due to carrying in the ear canal
mycoplasma capri
what are the 3 routes of transmission for M. capri
- carrier in ear canal
- vertical (colostrum)
- direct
M. capri is known for causing systemic disease in what group
goat kid
what causes infectious caprine/ovine keratoconjunctivitis
mycoplasma conjunctivae
what causes porcine enzootic pneumonia
mycoplasma hypopneumoniae
what is the clinical sign of porcine enzootic pneumonia
persistent, non-productive dry cough, decreased weight gain
what is the pathogenesis of MHP in 5 steps
- stressors
- colonization to the ciliated respiratory epithelium
- ciliostasis, loss of cilia, decreased epithelial cells and goblet cells
- loss of function of the mucociliary apparatus
- predispose to secondary bacterial bronchopneumonia
mycoplasma hyorhinis is commensal to what species
swine
what species do mycoplasma gallisepticum infect. what is the disease manifestation for each
chicken = chronic resp. disease
turkey = infectious sinusitis
what is the transmission of M. gallisepticum
- aerosol
- direct contact
- venereal
- vertical transmission
what is Mycoplasma synoviae
disease in chickens and turkeys that manifests as generalized respiratory disease and can spread systemically to air sac and joints
what is mycoplasma meleagridis
respiratory disease in turkeys
what is mycoplasma iowae
respiratory and joint disease in chickens/turkeys with immunosuppression
what is mycoplasma gallinarum
severe bronchitis when co-infected with IBV
what is mycoplasma anatum
respiratory and systemic infection in ducks
describe the morphology of chlamydiae
small, gram -, pleomorphic cocci intracellular parasite
describe the life cycle of chlamydiae in 5 steps
1.infectios EB enters
2. EB to RB differentiation
3. RB fission and inclusion growth
4. RB to EB differentiation
5. release EBs
what are the 2 phases of chlamydia life cycle
biphastic (elementary and reticulate)
decribe chlamydia psittaci
common asymptomatic disease with non-specific clinical signs and extensive shed period in a variety of birds
how is psittacosis diagnosed
- PCR
- culture
- serology
T/F: psittacosis causes parrot fever in humans
TRUE
what does chlamydia felis cause
conjunctivitis - rarely respiratory
