Specimen Handling Protocols

Question 1

Specimen Handling Protocols

Answer 1

-For clinical, environmental, or research studies the results are only as good as the specimen you start with
-A poorly collected or processed specimen is unusable and will delay the identification of the pathogen
>Patients are the ones that will be affected
-Pure cultures are needed to identify organisms
>Most specimens sent to lab will be mixed cultures

Question 2

Procedures for Clinical Specimen Collection

Answer 2

• The specimen must be collected before starting antimicrobial therapy
• The specimen must be representative of the condition
• Adequate amounts of material must be collected
• Proper transport is vital
• A series of samples may be necessary
• Aseptic technique and sterile containers must be used
• Specimens must be kept moist
• Specimens must be labeled properly

Question 3

Procedures for Clinical Specimen Collection: The specimen must be collected before starting antimicrobial therapy

Answer 3

bacteria will disappear 2 hours after the start of therapy

Question 4

Procedures for Clinical Specimen Collection: The Specimen must be representative of the condition

Answer 4

Saliva versus sputum

Question 5

Procedures for Clinical Specimen Collection: Adequate amounts of material must be collected

Answer 5

multiple tests may be necessary

Question 6

Procedures for Clinical Specimen Collection: Proper transport is vital

Answer 6

• some organisms are temperature and oxygen sensitive

- don’t allow specimen to sit out

Question 7

Procedures for Clinical Specimen Collection: A series of samples may be necessary

Answer 7

• blood cultures require 6-8 samples

- sputum samples require 2 per day for 3 days

Question 8

Procedures for Clinical Specimen Collection: specimens must be kept moist

Answer 8

• use transport media

- check expiration date on tubes and swabs

Question 9

Blood Cultures

Answer 9

-Blood is injected into bottles that contain culture media
-Pathogens which have invaded the bloodstream can be detected very quickly
>89% within 24 hours
>97% within 48 hours
>Septicemia, Enteric Fever, Bacterial endocarditis
-Bottles are continuously monitored
-Readings are transmitted to a computer compiler

Question 10

Blood Cultures: Detect

Answer 10

• Septicemia
• Enteric Fever
• Bacterial endocarditis

Question 11

Urine Culture Colony Counts

Answer 11

-When performing a urine colony count both the number of cells and the type of bacteria growing is important
>Quantitative= number of cells
>Qualitative= type of bacteria (Genus and Species)

Question 12

Urine Cultures

Answer 12

• The urine is collected in a sterile container using the clean catch, midstream method
• A calibrated loop (0.001 ml) is used to inoculate the plate
• A single line is drawn down the center of the plate, and then is spread over the entire plate perpendicularly
• After the plate is incubated you can count the number of colonies on the plate and determine the amount of bacteria in the sample
• Number of colonies X dilution factor;
  ex: 40 colonies X 1000= 40000 microbes/ml of urin

Question 13

Formula for determining the amount of bacteria in the sample of urine (Quantitative Evaluation)

Answer 13

Number of colonies X dilution factor

ex: 40 colonies (number visually counted on plate) X 1000= 40000 microbes/ml of urine
- 1000= dilution factor

Question 14

Quantitative Evaluation of Urine

Answer 14

• Multiply the number of colonies by the dilution factor (loop size) to get the number of bacteria in 1 ml of urine
  ex: 40 colonies X 1000=40000 microbes/ ml of urine

Question 15

Quantitative Evaluation Chart

Answer 15

Colonies/0.001 ml Microbes/ml of urine Significance
0-9 0-9000 no growth
10-99 10,000-99,000 infection
100+ 100,000+ Acute Infection

Question 16

Quantitative Evaluation of Urine Tool

Answer 16

Quebec Colony Counter

-helps determine how many colonies on a plate; uses magnifying glass

Question 17

Throat Cultures

Answer 17

Throat cultures can be swabbed directly on media plates
-Uses Media:
>Blood Agar
>Chocolate Agar
-rub swab across tonsillar areas and the posterior pharynx, specifically targeting any inflamed areas

Question 18

Stool Cultures

Answer 18

-Approximately 50% of fecal material is bacteria
-Feces may contain >300 different types of bacteria
-Media that is used to culture stool for:
>Gram Positive Organisms:
1. Mannitol Salt agar
2. Phenylethyl Alcohol agar
>Gram Negative Enteric Organisms:
1. MacConkeys agar
2. Eosin Methylene Blue agar
What other media?
-Blood agar
-Thioglycolate broth

Question 19

Stool Cultures: Media for Gram (+) Organisms

Answer 19

• Mannitol Salt Agar

- Phenylethyl Alcohol Agar

Question 20

Stool Cultures: Media for Gram (-) Enteric Organisms

Answer 20

• MacConkey’s Agar

- Eosin Methylene Blue Agar

Question 21

Stool Collection Preservatives

Answer 21

>C+S Vial (orange cap)
-Culture and Sensitivity
Includes: Salmonella, Shigella, Campylobacter
>SAF Vial (yellow cap)
-Ova and Parasites
-Fecal WBC, Giardia, Cryptosporidium 
>Clean Vial (white cap)
-(Refrigerate within 1 hour)
-Clostridium difficile (C-Diff), Fecal Fat (qualitative), Occult Blood, Rotavirus, Reducing substances

Question 22

Water Testing for Coliforms

Answer 22

presence of E.Coli indicates contamination with sewage