- #1
vicki
- 7
- 0
please help, how to identify an unknown microbe? 
How to identify an unknown microbe?
- Thread starter vicki
- Start date
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SUMMARY
Identifying an unknown microbe involves several critical steps, including host type assessment, symptom analysis, gram staining, and morphological examination. For mixed cultures, tissue, or environmental samples, initial isolation on rich non-specific media is essential, with incubation temperatures of 37°C for mammalian tissue and 15-20°C for environmental samples. Subsequent tests such as gram staining, wet mounts, catalase, and peroxidase tests guide towards specific bacterial groups. Reference materials like Bergey's Manual of Determinative Bacteriology are crucial for classification and biochemical testing.
PREREQUISITES- Understanding of gram staining techniques
- Familiarity with microbiological culture methods
- Knowledge of biochemical tests such as catalase and peroxidase tests
- Basic skills in DNA isolation and PCR amplification
- Research the use of Bergey's Manual for bacterial classification
- Learn about the principles of PCR and DNA sequencing
- Explore the application of biochemical test strips for microbial identification
- Study the significance of morphology in microbial classification
This discussion is beneficial for microbiologists, laboratory technicians, and researchers involved in microbial identification and classification processes.
please help, how to identify an unknown microbe? - #2
Jikx
- 206
- 0
hmm..
host type
symptoms
gram stain (+ve, -ve)
morphology (size, shape, other fixtures)
proteins (western blot?)
dna (PCR)
and that's all i can remember.. never did do microbiology.
host type
symptoms
gram stain (+ve, -ve)
morphology (size, shape, other fixtures)
proteins (western blot?)
dna (PCR)
and that's all i can remember.. never did do microbiology.
- #3
iansmith
Staff Emeritus
Science Advisor
Gold Member
- 1,317
- 2
Are you starting from a mixed culture, tissue sample or sample from environment.
The type of culture will influence the steps required to identify your organism.
For mixed culture, tissue and environmental sample, first streak for isolation of rich non specific media. Use the temperature that is most appropriate. Tissue sample coming from a mammal should be grown at 37C whereas an environmental sample should be grown between 15C and 20C
Once you have isolated the organism you do a gram stain and also do a wet mount. The gram strain will help you identified the morphology of the organims and how it colonies are formed. For example, a gram positive cocci that forms line will be a streptococcus. The wet mount will tell you if your organism is mobile or not.
You also need to do catalse and peroxidase test. This guide you towards are more specific group.
You can then do more group specific stain such as spore stain.
Once you have this information look in the Bergey's. Bergey's is the bible of bacteriologist. It has all classified bacteria. If it is not a bacteria than use another taxonomy book.
Bergey's or the other taxonomy book will help you to find the biochemical test required to identify the organism.
You also do not have to carry the biochemical test. There is strips that are sold that included all the test for a specific organims.
http://www.biomerieux-usa.com/clinical/microbiology/api/apiproducts.htm
To support your identification and to have a more specific results, you will need do isolated DNA from you pure culture and amplifed and sequence the small ribosmal unit gene.
Strain/serotype/species specific test will also be required for additional and better classification. You will again referred to the bergey or any litterature that is specific for that organism.
The type of culture will influence the steps required to identify your organism.
For mixed culture, tissue and environmental sample, first streak for isolation of rich non specific media. Use the temperature that is most appropriate. Tissue sample coming from a mammal should be grown at 37C whereas an environmental sample should be grown between 15C and 20C
Once you have isolated the organism you do a gram stain and also do a wet mount. The gram strain will help you identified the morphology of the organims and how it colonies are formed. For example, a gram positive cocci that forms line will be a streptococcus. The wet mount will tell you if your organism is mobile or not.
You also need to do catalse and peroxidase test. This guide you towards are more specific group.
You can then do more group specific stain such as spore stain.
Once you have this information look in the Bergey's. Bergey's is the bible of bacteriologist. It has all classified bacteria. If it is not a bacteria than use another taxonomy book.
Bergey's or the other taxonomy book will help you to find the biochemical test required to identify the organism.
You also do not have to carry the biochemical test. There is strips that are sold that included all the test for a specific organims.
http://www.biomerieux-usa.com/clinical/microbiology/api/apiproducts.htm
To support your identification and to have a more specific results, you will need do isolated DNA from you pure culture and amplifed and sequence the small ribosmal unit gene.
Strain/serotype/species specific test will also be required for additional and better classification. You will again referred to the bergey or any litterature that is specific for that organism.
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