Identification Of Bacteria Question And Answers

Identification Of Bacteria

Question 1. Discuss laboratory procedure for identification of bacteria from throat swab.
Or
Discuss laboratory procedure of throat swabs and identification of bacteria.
Answer:

Bacteria Introduction: 

• The swab is removed gently without touching the teeth, gums, or tongue. It is then placed in a sterile tube for immediate delivery to a laboratory.
• The throat material is cultured on blood agar that has been prepared as a broth and poured into Petri dishes (plates) where it solidifies into a gel.
• Blood agar is usually made from the cell walls of red algae (also triplicate soy, heart infusion, or ToddHewit agar) and sheep’s blood.
• When the throat swab reaches the laboratory, the microbiologist uses it to make streaks directly across a blood agar plate.
• The covered plate is allowed to incubate at a specific temperature (35°-37°C) for 24 to 48 hours to foster the growth of bacteria.
• The bacteria will grow in clusters called colonies. If the organism is a group A hemolytic Streptococcus, an area immediately around the bacterial colony will show hemolysis (the breaking up or lysing of red blood cells), leaving a clear zone surrounding the colony.

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• This helps a technician identify a hemolytic streptococcus organism visually.
• Other types of bacteria may grow in differently sized or shaped colonies allowing the microbiologist to differentiate the bacteria.
• A sample of the bacterial colony may also be examined microscopically to evaluate the bacterial type or morphology.
• Samples of the bacteria may be restreaked on another agar plate with small disks of specific antibiotics to see which antibiotics destroy the bacteria (sensitivity testing).
• The physician may then prescribe the most effective antibiotic