Bacteriology 6: Staphylococci

Question 1

What are bacteria groups based on?

Answer 1

The type of inflammation they induce

Question 2

What type of inflammation do pyogenic bacteria form?

Answer 2

• Puss forming
• Acute inflammation
• See predominantly neutrophils

Question 3

What type of inflammation do pyogranulomatous bacteria form?

Answer 3

Mixture of acute and chronic inflammation
- We will see a mixture of cells
–Polymorphonuclear neutrophils
– Macrophages
– Lymphocytes
– + or - eosinophils if fungal

Question 4

What type of inflammation do Granulomatous bacteria form?

Answer 4

We see central necrosis surrounded by:
- giant epitheliod cells (activated macrophages)
- macrophages
- lymphocytes
- Granulocytes
- Thick fibrous capsule

Question 5

What type of inflammation do necrotizing bacteria form?

Answer 5

We see a lot of cellular debris:
- Toxic cells
- Inflammatory cells
- the causative bacteria

Question 6

What are the types of Gram + cocci bacteria we are discussing?

Answer 6

• Staphylococci
• Streptococci

Question 7

What are types of pyogenic bacteria?

Answer 7

• Staphylococci (gm+ cocci)
• Streptococci (gm+ cocci)
• Trueperella (gm+ rods)
• Corynebacterium (gm+ rods)

Question 8

What are the types of gram + rods?

Answer 8

Clostridium
Actinomyces
Nocardia
Dermatophilus
Rhodococcus
Trueperella
Corynebacterium
Mycobacteria

Question 9

What are types of pyogranulomatous bacteria?

Answer 9

• Staphylococci (gm+ cocci)
• Actinomyces (gm+ rods)
• Nocardia (gm+ rods)
• Dermatophilus (gm+ rods)
• Rhodococcus (gm+ rods)

Question 10

What are types of granulomatous bacteria?

Answer 10

Mycobacteria (gm+ rods)

Question 11

What are types of necrotizing bacteria?

Answer 11

Clostridium (gm+ rods)

Question 12

Where do pyogenic bacteria cause dx?

Answer 12

Extracellular

Question 13

What are hallmarks of inflammation?

Answer 13

• Increased number of cells in fluid
• Increased number of protein in fluid

Question 14

What is coagulase test meaning?

Answer 14

• It differentiates between weakly virulent and highly virulent
  + mean highly virulent
• mean weakly virulent

Question 15

Where are coagulase positive staphylococci found?

Answer 15

Skin mucocutaneous junctions
Distal nasal passage
External nares
Rectum

Question 16

Where are coagulase negative staphylococci found?

Answer 16

skin- normal flora

Question 17

Factors helping staphylococci be good pathogens

Answer 17

Capsule or pseudocapsule
Exotoxins- Leukotoxins and hemolysins
Intracellular survival
Biofilm survival

Question 18

How does the capsule help cause disease?

Answer 18

• Anti-phagocytic

Question 19

Non-pathogenic (coag-neg) staphylococci interaction with macrophages?

Answer 19

Macrophages can easily phagocytize coag-neg staphylococci

Question 20

How do exotoxins help cause disease?

Answer 20

Many different exotoxin
Hemolysins and leukotoxins are important for virulence
—- These are cytotoxic and lethal (aka damage cells)
—- Leukotoxins kills phagocytes therefore assist in evading the immune system

Question 21

How does being a facultative intracellular bacteria assist in causing disease

Answer 21

Evade the immune system by:
- Killing phagocytes
- avoid antibodies
- avoiding abx that act extracellular

Question 22

What kind of infection can facultative intercellular bacteria cause?

Answer 22

PI - chronic

Question 23

What kind of pathogen are staphylococci?

Answer 23

Opportunistic pathogens: require compromise for host-pathogen interaction

Question 24

Are any staphylococci pathognomic?

Answer 24

No

Question 25

diseases caused by staphylococci?

Answer 25

Pyoderma (VERY common)
Mastitis
Greasy pig disease (Exudate dermatitis)
Musculoskeletal infections: Osteomyelitis, Septic arthritis
Urogenital tract infections: Cystitis, Prostatitis

Question 26

What rules are you supposed to follow in diagnosing staphylococci?

Answer 26

Part of normal flora in sterile site so follow four point rule:
- the sample must be collected in appropriate fashion from site of infection
- there must be evidence of inflammation in the sample
- good if there is evidence of bacteria in the sample
- the bacteria isolate must have the opportunity and be capable of causing this dx