Page 120 - LECTURE NOTES
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- Gram-negative coccobacilli that could be Y. pestis.
b. Examine the specimen using culture
Blood agar and MacConkey agar cultures are used for isolation of bacteria, which cause
common skin diseases.
- Look for colonies like
o Staphylococcus aureus
o Streptococcus pyogenes
o Pseudomonas aeruginosa
o Enterococci
o Proteus species
o Escherichia coli
- Modified Tinsdale medium culture could be used if cutaneous diphtheria is
suspected
- Use room temperature for Blood agar and MacConkey agar if Yersina pestis is
suspected.
Culture the specimen
- Flame and sterilize wire loops before & after use
- Flame the necks of specimen bottles, culture bottles, & tubes after removing &
before replacing caps.
- Inoculate the culture media
- Make slide preparations from specimens after inoculating the culture media
- The inoculated media should be incubated as soon as possible. Incubate the
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blood agar & MacConkey agar aerobically at 35 – 37 C.
- After 2 days and onwards of incubation examine both cultures for the common
bacteria of skin infection.
- Report the identified bacterial from the culture
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