Bacteriology 6/7 :Gram + Pyogenic infections

Question 1

Gram + bacteria will we be studying?

Answer 1

Staphylcocci

Streptococci

both are pyogenic

Question 2

what does pyogenic mean?

Answer 2

Acute inflammation

We will see a predominantly neutrophils
(PUS)

Question 3

What does Pyogranulomatous mean?

Answer 3

Mixture of acute and chronic inflammation

We will see a mixture of cells (PMNs, macrophages, lymphocytes, +/- eosinophils if fungal)

Question 4

What does true Granulomatous mean?

Answer 4

Chronic inflammation

seen central necrosis surrounded by giant epithelioid cells, macrophages, lymphocytes, some granulocytes, and surrounded by a thick fibrous capsule.

Question 5

What does necrotizing do and how is it seen?

Answer 5

Acute inflammation

seen just cellular debris, potentially a few toxic, inflammatory cells and the causative bacteria
ex. gram + pore-forming rods

Question 6

Pyogenic bacteria cause inflammation primarily by acting as ______________ bacteria

Answer 6

EXTRAcellular

Question 7

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?

Answer 7

Bacterial infection

We know the horse was given a shot and that it was something viral, fungal, or parasitic that could’ve triggered it

Question 8

What does VINDICATE stand for in differential diagnosis?

Answer 8

V= vascular
I=infectious
N=neoplastic
D=degenerative
I=inflammation/intoxication
C= congenital
A=autoimmune
T=traumatic
E=endocrine/metabolic

Question 9

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

Answer 9

Fine Needle Aspiration
( we can do this because a joint is normally STERILE)

Question 10

Do we do surgical prep when collecting sample from a joint?

Answer 10

YES

because it is a sterile site

Question 11

The fluid collected is cloudy what can cause that?

Answer 11

Very turbid joint fluid
-increased number of cells
-increase amount of proteins

means inflammation

Question 12

What would you do after looking at the joint fluid?

Answer 12

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 -

Question 13

Following the joint aspiration, and the smear what would you do?

Answer 13

Do an interpretation

Question 14

If you see cocci in a smear what can you usually infer?
*hint gram

Answer 14

They are gram +

Question 15

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

Answer 15

24 hours

Question 16

when you interpret something might be either staphylococci or streptococci you need to consider what with medications?

Answer 16

You can NOT just give antimicrobials because bacterias act differently and this could be detrimental

Question 17

What is the 4 point rule for sterile sites?

Answer 17

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

Question 18

What we need to know about bacteria to make a good diagnostic?

Answer 18

• 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

Question 19

What form do Gram positive cocci bacteria make?

Answer 19

CLUSTERS

Faculative anaerobes

Question 20

What are the two species of Staphylococci have MAJOR clinical importance?

Answer 20

S. aureus (horses) other domestics

S. Pseudintermedius (DOGS)

*both are COAGULASE + (C+) (meaning + pathogenicity)

Question 21

Why are S. aureus and S. Pseudintermedius big deals?

Answer 21

Wide range of disease in animals/humans

both COAGULASE + (pathogenicity good)

Question 22

Where in the skin do (C+) Staphylococci like to hangout?

Answer 22

Mucocutaneous junctions

*normal flora

Question 23

Where else that considered normal flora can you find Staphylococci (C+)?

Answer 23

Distal nasal passage, external nares, and near rectum

Question 24

Are Staph good or bad pathogens?

Answer 24

GOOD

Range of virulence factors HELP

Question 25

What are the range of virulence factors that HELP cause disease?

Answer 25

Capsule

Exotoxins– leukotoxins/hemolysins

intracellular survival

biofilm formation

~urease, superantigens etc.

Question 26

How do capsules help bacteria?

Answer 26

Anti-phagocytic properties (Major defense)

• helps (C+)

Question 27

how do Exotoxins help bacteria?

Answer 27

Hemolysins- substance in blood that destroys RBC and liberates Hgb

leukotoxins- induce NETosis

Question 28

What are the 3 points that help Facultative Intracellular Bacteria

Answer 28

-killing by phagocytes

-immune system (ABs)

-antibiotics which act extracellularly

PERSISTENCE OF INFECTION (chronicity sometimes)

Question 29

What kind of pathogens are Staphylococci?

Answer 29

Opportunistic

Question 30

What are the 4 Pyogenic bacteria?

Answer 30

Staphylococci

Streptococci

Corynebacteria

Trueperalla

Question 31

What is the outcome of pyogenic infection?

Answer 31

PUS

Question 32

What is the different about Staphylococci VERSUS Streptococci?

Answer 32

STAPHylococci’s ability to survive INTRAcellularly

• abscesses with this bacteria may be chronic

Question 33

What other specific Diseases are involved with staphylococci

Answer 33

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