Bacteriology

Question 1

What is microscopy?

Answer 1

Direct visualization of bacteria through a microscope

Question 2

What is in vitro culture?

Answer 2

Planting specimens on appropriate culture media and performing ID by MALDI

Question 3

What are signs of inflammation?

Answer 3

Systemic: fever, lethargy and inappetence - bloodwork, leukocytosis, neutrophilia and left shift
Local signs: heat, swelling, pain, discharge and loss of function

Question 4

How do you know if you need to culture?

Answer 4

• If the definitive diagnosis would change the treatment, control or prognosis
  -If disease is very serious or life threatening

Question 5

What is empirical therapy?

Answer 5

Administration of therapy based on previous experience (may be someone Elses)

Question 6

When is empirical therapy indicated?

Answer 6

-High level of efficacy for proven treatment
-waiting for results for c/s
-cant afford c/s

Question 7

What should you base your empirical treatment on?

Answer 7

-Likely bacteria to cause the disease
-Likely antimicrobial sensitivity pattern
-other factors like location of infection, cost antibiotics and ease of administration

Question 8

What is a common pathogen that causes UTI in dogs?

Answer 8

E.coli (Rod) or staph pseudointemedius (Cocci)

Question 9

What is a common empirical treatment for an uncomplicated UTI?

Answer 9

Amoxicillin or amoxicillin-clavulanic acid, Cefpodoxime, Trimethoprim-sulfonamides

Question 10

If the dog returned and you know the owner had been Complient what is the next step?

Answer 10

Culture and sensitivity

Question 11

When is a specific diagnosis needed?

Answer 11

-Animal is significantly compromised (young or old or co-morbidities)
-Superinfection suspected
-Suspected pathogens don’t have predictable susceptibility pattern
-poor response to earlier therapy
-outbreak of disease
-suspect disease is reportable

Question 12

What are some suspect pathogens you would culture?

Answer 12

Staphs
Recurrent pyoderma
Strep Equi (strangles)
Reportable

Question 13

What are some things to consider when collecting a sample that may be used for culture and sensitivity?

Answer 13

Specific location, is the site sterile or does it have normal flora, when should you sample, what technique should you use

Question 14

What is the 4 point rule to make sure you collected sterily?

Answer 14

-Collected correctly
-inflammation was present
-organism present
-can it cause this disease

Question 15

If the site has normal flora what should you be asking yourself?

Answer 15

-Is what I found normal flora
-is it in excess numbers
-can it cause disease

Question 16

If you have a sample question what should you do?

Answer 16

Call the lab

Question 17

Samples for microbiology testing need to be…

Answer 17

kept cold (except dermatophytes, blood culture, CSF, joint fluid and anaerobic culture)

Question 18

If you have the choice between taking a tissue/fluid sample or a swab you should choose?

Answer 18

Tissue and fluid

Question 19

If you are going to send a sample for culture it must stay ….
You should never put samples you want to culture in…

Answer 19

Moist

Formalin, alcohol, EDTA or Heparin

Question 20

Why do microbiologist hate swabs?

Answer 20

-Dont get enough material (.5ml or % bacteria)
-Bacteria adhere to them and wont come off
-Dry out
-Exposed to air
-People thick them where they shouldn’t

Question 21

If you have to use a swab, what type should you use?

Answer 21

Flocked, plastic shaft
-Dry PCR
-Correct media
-Guarded if uterine or nasopharyngeal

Question 22

What do you use the following media for:
-Stuarts:
-Amies:

Answer 22

Stuart: aerobic or PCR
Amies: Aerobic, anaerobic or fungal

Question 23

Where should you use a swab?

Answer 23

Mucous membranes, ears, uterus, cornea

Question 24

What are 2 ways we evaluate samples?

Answer 24

Cytologically and culture

Question 25

Cytology can give you a pretty good…

Answer 25

presumptive diagnosis (many respiratory fungi ID this way)

Question 26

What are some pros and cons of fluid aspirations/centesis?

Answer 26

Pro: Preferred for all sample, easier for sterile technique, more material, cheap and easy
Neg: Bacteria dont like in them forever, like anaerobes

Question 27

What can you take an aspirate sample of?

Answer 27

Joint, thoracic, abdominal, blood, CSF, tracheal wash, pustule, abscess
no swab in fluid

Question 28

What are some pros and cons to tissue samples?

Answer 28

Pros: need to pass normal flora (draining tract), bacteria survive longer in tissues, tissue represent all path process

Cons: invasive, need sedation and anesthetic, expensive, need transport media, add sterile saline to keep specimen moist

Question 29

Tell me about blood cultures:

Answer 29

-Need special bottle (aerobic and anaerobic)
-Must take aseptically (prep for venipuncture, alcohol top, ml blood per bottle
-3 separate samples in 24 hours
(before antimicrobial therapy, or right prior to next dose
-don’t refrigerate

Question 30

What are some pros and cons of a free catch sample?

Answer 30

Pro: cheap, may be only way to collect
Con: contaminated with normal fora

Question 31

What are the major goals of transportation?

Answer 31

-Prevent contamination
-maintain viability of all organisms present
-Maintain ratio of bacteria in sample if mixed
(urine room temp, biopsy on dry ice)

Question 32

What are some major problems with transportation?

Answer 32

-sample drying (saline on all sides), this side up label
-exposure to noxious atmosphere
-Excess time delays

Question 33

What are key points to transportation?

Answer 33

-Deliver ASAP
-Deliver in proper primary and secondary containers
-Keep cool (4C) - unless room temp
-In correct transport media

Question 34

Results are only as good as the…

Answer 34

sample collected (bad sample = bad results)

Question 35

What are some microbiology rules?

Answer 35

-Problem list with differentials
-Empirical only when appropriate - using knowledge of bugs and drugs
-collect correct sample from correct site
-correct rules to interpert results
-NO draining tracts
-Always evaluate for inflammation and bacteria
-Transport to lab ASAP in right media at temp with history
-consider host factors and pathogen virulence
-4 point rule

Question 36

What are the steps to bacterial investigation:

Answer 36

1. Is there inflammation
2. Collect a sample for culture and susceptibility
3. Transport to lab

Question 37

If you have discospondlitis what are some of your differentials?

Answer 37

Fungal: aspergillus, blasto, histo, coccidia
Bacteria: staph, brucella, strep, pasturella
Non-infectious: congenital, healing and unstable fracture

Question 38

Can we treat emperically?

Answer 38

difficult site
serious consequence
zoonotic pathogen on list
no normal flora here
-NO emperical

Question 39

How would we sample for discospndlitis?

Answer 39

Aerobic, anaerobic, fungal blood and urine
-Blood if think hematogenous
-serology brucella
-CSF
(EDTA antimicrobial)

Question 40

Even if it is a predictable pathogen, but it is zoonotic what should we do?

Answer 40

Culture and sensitivity