1-Introduction to Microbiology Course Basics

Microbiology Course basics

1. Introduction to
Microbiology
Dr. Mohammed Elkady
Clinical Pathology Consultant,
M.B.B.CH, EFCpath

2. Why?
Role of Lab?
Humans?
Microbiology Role?

3. Infection:
=invasion of body tissues by disease-causing agents,
(infectiousagents = Microbe).
Infectious disease, also known as transmissible disease
or communicable disease, is illness resulting from
aninfection.

4. Microbe
A microbe = microorganism
=
a microscopic organism
single cell (unicellular)
multicellular

5. Microbiology
the science (logos)of small
(micro)life (bios)

6. Our aim
3 Major Stepsto reach diagnosis in Microbiology :
1-Specimen (collection, possible pathogens and
contaminants, .....)
2-Processing (media selection, staining, Identification,
....)
3-Reporting ( AST, ...)

7. 1-Specimen
Specimen: collection methods, transport and rejection
criteria (very critical)
Expected Pathogens , Flora and possible
contaminants

8. 2-Processing
Selection of Media for culture
Colony Characteristics
Gram Stain and bacteria classification
Bacterial Identification Tests
Selection of antibiotics for Sensitivity Tests

9. 3-Reporting
Clear Identification
Interpretation of results
AST
Recommendations
Preservation and archiving of samples

10. Samples:
Urine
Blood
Sputum
Stool
Throat swab
Wound swab
Genital (Semen/Vaginal swabs/discharge)
Ear/ Nose swab
Eye swab
Body fluids (CSF-Pleural-Peritoneal...)
Skin, Hairs, Nails ....

12. Classification of
Microorganisms
Classification by structure
Subcellular –DNA or RNA surrounded by a protein coat –
viruses →“Virology”
Prokaryotic –simple cell structure with no nucleus or
organelles –bacteria →“Bacteriology”
Eukaryotic –complex cell structure with nucleus and
specialized organelles –fungi →“Mycology”protozoa,
parasites →“Parasitiology”

13. Prokaryotes
DNA free in cytoplasm.
No Nucleus or organelles.
Bacteria
Cell wall

14. According to gram stain
Gram Positive :
Cocci
bacilli
Gram Negative
Cocci
bacilli

15. Cell envelope

16. Cell envelope (cont)

17. Gram stain

18. According to OXYGEN
REQUIREMENTS
Obligate aerobes: require oxygen to grow (e.g. Mycobacterium
tuberculosis).
Microaerophilic: optimal growth in low oxygen concentrations
(e.g. Campylobacter spp. at 5% O2).
Obligate anaerobes: require an oxygen-free environment to
grow (e.g. Clostridium spp.).
Facultative anaerobes: can grow in aerobic or anaerobic
conditions

19. Thanks

20. Workshop
K. pneumoniae in anaerobic blood culture bottle??
Gram stain: you forgot decolorizer and safranin→??
Define: AST, Strict anaerobe, Peptidoglycan

23. Thanks