Bacterial Disease - Importance and Examples

Question 1

Why are bacterial infections important?

Answer 1

Very common - seen every day in practice
Diagnosis can be more difficult than expected

Question 2

Methods of Bacterial Infection Diagnosis

Answer 2

Non-specific to bacterial infections
* Pyrexia
* Blood work
* Fluid samples
* Acute phase proteins
* Breed/species specifics

Specific to bacterial infections
* Culture and sensitivity

Question 3

How can pyrexia help diagnose?

Answer 3

Not specific to bacterial infections
* Would expect animal with bacterial infection to be pyrexic
* Subnormal temperature is a sign of severe sepsis
* Can assess temperature of specific areas on clinical exam
Heat is a sign of inflammation - potentially infection

Question 4

How can blood work help diagnose?

Answer 4

Not specific to bacterial infections
Expect to see changes in blood work
* Leucocytosis and neutrophilia in most bacterial infections
* Can have neutropaenia when severe because of margination (cells attracted to site of sepsis)
* Can have peripheral leucopenia with bacterial infections which cause diarrhoea (salmonella)

Question 5

Margination

Answer 5

When cells are being attracted to site of sepsis

Question 6

How can Fluid Samples help diagnose?

Answer 6

Sample fluid from site of sepsis
○ Tracheal wash
○ Peritoneal fluid
○ Joint fluid
○ Pleural fluid
Leucocytosis and neutrophilia
○ See degenerate neutrophils and toxic change
Can biopsy skin and organs

Question 7

Toxic change

Answer 7

Refers to how neutrophils are being made
How hard is bone marrow working

Neutrophil levels in BLOOD

Question 8

Degenerate Neutrophils

Answer 8

Sign of bacterial infections
* Refers to how they’re dying
* Neutrophil levels in TISSUES

Question 9

Left shift

Answer 9

More immature than segmented due to infection
* Bone marrow producing more new neutrophils and mature ones dying

Question 10

How can acute phase proteins help diagnose?

Answer 10

Bacterial infection causes increase in acute phase proteins due to inflammation
* Non-specific to bacterial infection
Moderate increase

Question 11

Acute phase proteins in specific species

Answer 11

Serum amyloid a - cats, horses
Activated protein C - dogs
Haptoglobin - cattle

Fibrinogen - general

Question 12

How can culture and sensitivity help diagnose?

Answer 12

Specific to bacterial infections
* Confirms and identifies bacteria
Allows for selection of correct antibiotic

Question 13

Limitations of culturing

Answer 13

Some fluids are difficult to culture:
* Cerebro-spinal fluid
* Joint fluid

Question 14

Limitations of sensitivity testing

Answer 14

Antibiotic might be sensitive in a petri-dish but not in a patient
* Won’t work if can’t get to site of infection

Question 15

What other methods of diagnosis for bacterial infections are there?

Answer 15

Ultrasound

Question 16

Diagnosis of pyometra

Answer 16

Large fluid filled uterus on ultrasound
* older unspayed bitch
* Off food
* Polydipsia
* Pyrexia
* purulent discharge from vulva

Question 17

Treatment of pyometra

Answer 17

Need to determine whether uterus is open or closed
* Open - needs surgery
* Closed - give antibiotics

Question 18

Diagnosis of septic pericarditis

Answer 18

• Hypoechoic fluid around heart on ultrasound
• Common in cows
  Wires pierce reticulum, diaphragm and penetrate pericardial sac
• leads to fluid accumulation and heart failure

Question 19

Treatment of septic pericarditis

Answer 19

Short term
* drained and managed with antibiotics

Long term
* Poor prognosis

Question 20

Diagnosis of pleuropneumonia

Answer 20

Seen in horses
* Hypoechoic fluid in pleural space
* stands of fibrin connecting surface of lung to parietal pleura

Question 21

Treatment of pleuropneumonia

Answer 21

Antibiotics alone won’t work
* Need to remove inflammatory and bacterial fluid
flush with sterile fluids
* Systemic and local antibiotics
* Products to breakdown fibrin

Question 22

Diagnosis of peritonitis

Answer 22

• Increased echogenicity on ultrasound in peritoneal space

Question 23

Treatment of peritonitis

Answer 23

Unlikely to get better with just antibiotics
* Need to lavage abdomen to remove inflammatory fluid

Question 24

What does bacterial infection treatment depend on?

Answer 24

Location of infection
Underlying cause
Does the bacteria need to be killed?
Does body just need support to fight infection?