Bacteriology 6/7 :Gram + Pyogenic infections Flashcards
Gram + bacteria will we be studying?
Staphylcocci
Streptococci
both are pyogenic
what does pyogenic mean?
Acute inflammation
We will see a predominantly neutrophils
(PUS)
What does Pyogranulomatous mean?
Mixture of acute and chronic inflammation
We will see a mixture of cells (PMNs, macrophages, lymphocytes, +/- eosinophils if fungal)
What does true Granulomatous mean?
Chronic inflammation
seen central necrosis surrounded by giant epithelioid cells, macrophages, lymphocytes, some granulocytes, and surrounded by a thick fibrous capsule.
What does necrotizing do and how is it seen?
Acute inflammation
seen just cellular debris, potentially a few toxic, inflammatory cells and the causative bacteria
ex. gram + pore-forming rods
Pyogenic bacteria cause inflammation primarily by acting as ______________ bacteria
EXTRAcellular
Used to run fast case
The horse presented for lameness and then he was given a INTRA-ARTICULAR corticoid shot to deal with it.
When he came back his leg was now also swollen and hot.
What do we expect it to be?
Bacterial infection
We know the horse was given a shot and that it was something viral, fungal, or parasitic that could’ve triggered it
What does VINDICATE stand for in differential diagnosis?
V= vascular
I=infectious
N=neoplastic
D=degenerative
I=inflammation/intoxication
C= congenital
A=autoimmune
T=traumatic
E=endocrine/metabolic
With our assessment we hypothesized that this was a bacterial infection and now we what would be the best way to collect the sample?
We have a swollen joint with fluid in it
Fine Needle Aspiration
( we can do this because a joint is normally STERILE)
Do we do surgical prep when collecting sample from a joint?
YES
because it is a sterile site
The fluid collected is cloudy what can cause that?
Very turbid joint fluid
-increased number of cells
-increase amount of proteins
means inflammation
What would you do after looking at the joint fluid?
MAKE A SMEAR–stain with Diff quik
You you can say cocci and other shapes but because it’s diff quik you can NOT tell if its gram + or -
Following the joint aspiration, and the smear what would you do?
Do an interpretation
If you see cocci in a smear what can you usually infer?
*hint gram
They are gram +
If you need to culture in this case joint fluid, how long should the incubation be to see growth?
this should be in blood culture media
24 hours
when you interpret something might be either staphylococci or streptococci you need to consider what with medications?
You can NOT just give antimicrobials because bacterias act differently and this could be detrimental
What is the 4 point rule for sterile sites?
Sample must be collected in an APPROPRIATE fashion from the ACTUAL site of infection
There must be evidence of INFLAMMATION
Good (not essential) EVIDENCE OF BACTERIA
The bacteria isolated must have the OPPORTUNITY to, and be CAPABLE of causing disease
What we need to know about bacteria to make a good diagnostic?
- What is the name and what type of bacteria are they?
-Where do the come from? (source)
-How do the bacteria cause disease ?(Virulence)
-How does this disease develop? (pathogenesis)
-What diseases do they cause and what are the clinical signs?
-How do you diagnose infections
-How do you treat these infections
What form do Gram positive cocci bacteria make?
CLUSTERS
Faculative anaerobes
What are the two species of Staphylococci have MAJOR clinical importance?
S. aureus (horses) other domestics
S. Pseudintermedius (DOGS)
*both are COAGULASE + (C+) (meaning + pathogenicity)
Why are S. aureus and S. Pseudintermedius big deals?
Wide range of disease in animals/humans
both COAGULASE + (pathogenicity good)
Where in the skin do (C+) Staphylococci like to hangout?
Mucocutaneous junctions
*normal flora
Where else that considered normal flora can you find Staphylococci (C+)?
Distal nasal passage, external nares, and near rectum
Are Staph good or bad pathogens?
GOOD
Range of virulence factors HELP
What are the range of virulence factors that HELP cause disease?
Capsule
Exotoxins– leukotoxins/hemolysins
intracellular survival
biofilm formation
~urease, superantigens etc.
How do capsules help bacteria?
Anti-phagocytic properties (Major defense)
- helps (C+)
how do Exotoxins help bacteria?
Hemolysins- substance in blood that destroys RBC and liberates Hgb
leukotoxins- induce NETosis
What are the 3 points that help Facultative Intracellular Bacteria
-killing by phagocytes
-immune system (ABs)
-antibiotics which act extracellularly
PERSISTENCE OF INFECTION (chronicity sometimes)
What kind of pathogens are Staphylococci?
Opportunistic
What are the 4 Pyogenic bacteria?
Staphylococci
Streptococci
Corynebacteria
Trueperalla
What is the outcome of pyogenic infection?
PUS
What is the different about Staphylococci VERSUS Streptococci?
STAPHylococci’s ability to survive INTRAcellularly
- abscesses with this bacteria may be chronic
What other specific Diseases are involved with staphylococci
Pyoderma
DOG (~birds)
Greasy Pig Disease
PIGS–dermatitis
Mastitis
DAIRY COWS~~sheep/goat
Musculoskeletal infections
Urogenital tract infections
IMPLANT INFECTIONS
-BOTH coagulase + and -
–biofilms from significant host compromise
