12 Questions
What percentage of bacterial identifications reported by clinical microbiology laboratories are distributed across only 27 taxa?
95%
How many different bacterial species or taxa are reported by clinical microbiology laboratories?
530
In the general approach for bacterial identification, what is the final step after performing an identification technique?
Results = name of bacteria
Out of the 530 different bacterial species or taxa reported, how many make up more than 90% of the identifications?
16
Which step in the general approach for bacterial identification involves culturing on isolation media?
Step 2: Culturing on isolation media
What does the high frequency of only 27 taxa being reported suggest about the other bacterial taxa?
They are infrequently identified and reported
Which method of bacterial identification is based on the characterization of proteome of the bacteria?
Physical methods
What is the primary stain used in the Gram stain technique for bacteria identification?
Crystal violet
Which method of bacterial examination involves the application of strong carbol fuchsin with heat?
Ziehl-Neelsen stain
What is the purpose of antimicrobial sensitivity tests in laboratory investigations of microbial infections?
Testing bacteria's response to antibiotics
Which culture media type is used for the isolation and identification of pathogenic organisms?
Blood agar
What continues to expand and play a greater role in diagnostic microbiology according to the text?
Molecular and advanced methods
Study Notes
Clinical Microbiology Laboratory Reporting
- Approximately 530 different bacterial species or taxa are reported by clinical microbiology laboratories.
- 95% of bacterial identifications are distributed across only 27 of these taxa.
- Over 90% are represented by 16 different taxa.
General Approach for Bacterial Identification
- 4-step process:
- Sampling
- Culturing on isolation media
- Performing an identification technique
- Results: name of bacteria
- Identification techniques:
- Physical methods: based on proteome characterization
- Genetical methods: based on specific gene characterization
- Biochemical methods: based on metabolic pathway characterization
- Results are compared to databases to identify unknown bacteria
Future Trends of Organism Identification
- New species associated with human infections will continue to be discovered.
- Well-known species may change their characteristics, affecting identification criteria.
- Identification schemes and strategies must be continually reviewed and updated.
- Molecular and advanced methods will continue to expand and play a greater role in diagnostic microbiology.
Laboratory Investigation of Microbial Infections
- Examining specimens to detect, isolate, and identify pathogens using:
- Microscopy
- Culture techniques
- Biochemical reactions
- Serological identification
- Molecular biology techniques
- Antimicrobial sensitivity tests
Microscopy
- Examining microorganisms for:
- Bacterial motility: hanging drop method
- Morphology and staining reactions of bacteria
- Staining techniques:
- Simple stain: methylene blue stain
- Gram stain: differentiation between Gm+ve and Gm-ve bacteria
- Ziehl-Neelsen stain: staining acid-fast bacilli
Learn about the rationale for approaching bacterial species identification in clinical microbiology based on the distribution of identified taxa. Explore the limited identification of a vast number of bacterial species in laboratory reports.
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