1. Introduction to Microbiology
Introduction to Clinical Laboratory Sciences
Introduction to Microbiology
CLS 245

2. Introduction to Clinical Laboratory Sciences
What is Microorganism?
Microorganisms ( or Microbes) are vey small organism that can’t be seen by naked eyes.
However, these Microbes can be seen with the aid of microscope.
These microorganisms can be divided into 4 subgroups: Bacteria,, Fungi, Viruses and Parasites.
Microbiology is a broad field that include the study of all types of microorganisms.

4. Cont.. Medical Microbiology is the study of microorganisms: Bacteria
Fungus
Parasites
Viruses
Most can only be seen with the microscope!

5. Cont..
Medical Microbiology studies are usually performed on human blood and body fluids.
Microorganisms can cause disease in humans.
Microbiologists determine the type of microorganism causing the disease and find a drug, usually an antibiotic, to inhibit the microorganism.
Microbiologists continue to study the microorganisms through research to determine new antibiotics

6. Cont..
Microorganisms are studied in clinical hospital laboratories, reference laboratories, and research facilities.

7. Prokaryotes vs Eukaryotes
Introduction to Clinical Laboratory Sciences
Prokaryotes vs Eukaryotes
Before getting into Microbiology, it is important to
understand the differences between Prokaryotes
and Eukaryotes.
Adapted from:

8. Prokaryotes vs Eukaryotes
Introduction to Clinical Laboratory Sciences
Prokaryotes vs Eukaryotes
-ER , Golgi , Mitochondria and Lysosome are in Eukaryotes but not in pro
-human are eukaryotes
Yeast also are eukaryotes, so when you get fungal infection it is hard to treat with antibiotics.

9. Introduction to Clinical Laboratory Sciences
Viruses
-Virology is study of viruses.
-Viruses are very small microorganisms (smaller than bacteria) and they can’t grow or reproduce apart from living cells.
-They are too small to be seen by microscope.
-Viruses are not alive, why?
Viruses are not a live, why?
They can’t reproduce or grow apart from living cell, they also can’t produce energy.

10. Viruses Viruses have wide variety of structure
but they all share 2 important
element:
Genetic material (DNA or RNA)
Protein coat or capsid

11. Introduction to Clinical Laboratory Sciences
Fungi
The study of fungi is called Mycology.
The fungi are a group of eukaryotic microorganisms, some of which are capable of causing superficial, cutaneous, subcutaneous, or systemic disease.
However, some fungi are also directly important as a food for human (making a bread) or as a treatment ( producing penicillin).

12. Introduction to Clinical Laboratory Sciences
Fungi cont
Introduction to Clinical Laboratory Sciences
Mykes (Greek word) means Mushroom.
Fungi are eukaryotes , differ from bacteria and other
prokaryotes.
Fungi digest dead organic matter.
Molds and mushroom are multicellular while Yeast are
unicellular
Adapted from DR T.V Rao MD
Yeast: unicellular fungi
Molds: Multicellular fungi

13. Introduction to Clinical Laboratory Sciences

14. Introduction to Clinical Laboratory Sciences
Parasites
Introduction to Clinical Laboratory Sciences
Medical parasitology: “the study and medical implications of parasites that infect humans”
A parasite: “a living organism that acquires some of its basic nutritional requirements through its intimate contact with another living organism”. Parasites may be simple unicellular protozoa or complex multicellular metazoa
Eukaryote: a cell with a well-defined chromosome in a membrane-bound nucleus. All parasitic organisms are eukaryotes
Protozoa: unicellular organisms, e.g. Plasmodium (malaria)
Metazoa: multicellular organisms, e.g. helminths (worms) and arthropods (ticks, lice)
Adapted from
Angela Allen, Research Assistant, The School of Medicine, Swansea University, Swansea, UK
Dr. Stephen Allen, Senior Lecturer in Paediatrics and Honorary Consultant Paediatrician, The School of Medicine, Swansea University, Swansea, UK

15. Introduction to Clinical Laboratory Sciences
Cont. Parasite
Host: “the organism in, or on, which the parasite lives and causes harm”
Intermediate host: “the organism in which the parasite lives during a period of its development only”
Vector: “a living carrier (e.g.an arthropod) that transports a pathogenic organism from an infected to a non-infected host”. A typical example is the female Anopheles mosquito that transmits malaria
Adapted from
Angela Allen, Research Assistant, The School of Medicine, Swansea University, Swansea, UK
Dr. Stephen Allen, Senior Lecturer in Paediatrics and Honorary Consultant Paediatrician, The School of Medicine, Swansea University, Swansea, UK

16. Introduction to Clinical Laboratory Sciences
E. Coli O157:H7 can make you very sick.
What are bacteria?
Single celled organisms
Very small
Need a microscope to see
Can be found on most materials and surfaces
Billions on and in your
body right now
Streptococcus can cause strep throat.
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006
This E. coli helps you digest food.

17. Introduction to Clinical Laboratory Sciences
What do they look like?
Three basic shapes
Rod shaped called bacilli (buh-sill-eye)
Round shaped called cocci (cox-eye)
Spiral shaped
Some exist as single cells, others
cluster together
Bacilli
Cocci
Spiral
Cluster of cocci

18. Introduction to Clinical Laboratory Sciences
Bacteria are ALIVE!
What does it mean to be alive?
They reproduce (make more of themselves)
They need to eat

19. Introduction to Clinical Laboratory Sciences
How do bacteria eat?
Photosynthetic bacteria
Some make their own food from sunlight—like plants
Some are scavengers
Share the environment around them
Example: The bacteria in your stomach are now eating what you ate for breakfast
Some are warriors (pathogens)
They attack other living things
Example: The bacteria on your face can attack skin causing infection and acne
Harmless bacteria on the stomach lining
E. Coli O157:H7
is a pathogen

20. Introduction to Clinical Laboratory Sciences
What is a pathogen?
Bacteria that make you sick
Why do they make you sick?
To get food they need to survive and reproduce
How do they make you sick?
They produce poisons (toxins) that result in fever, headache, vomiting, and diarrhea and destroy body tissue

21. Where do you get a pathogen?
Introduction to Clinical Laboratory Sciences
Where do you get a pathogen?
Indirect contact
Contact with people who are sick
Direct or indirect
Food, Water, or other Surfaces that are contaminated
Foods that could be contaminated
Direct contact

22. Are all bacteria pathogens?
Introduction to Clinical Laboratory Sciences
Are all bacteria pathogens?
No, most are harmless
Some are even helpful
Examples of helpful bacteria:
Lactobacillus: makes cheese, yogurt, & buttermilk and produces vitamins in your intestine
Leuconostoc: makes pickles & sauerkraut
Pediococcus: makes pepperoni, salami, & summer sausage
USDA NIFSI Food Safety in the Classroom©
University of Tennessee, Knoxville 2006

23. Tools and instruments in Microbiology lab
Safety hoods are used to avoid splashing and
inhaling possible pathogens.
Agar plate for bacterial growth
Slide used to make Bacterial smear And stain them
Microscope to visualize the bacteria

24. Introduction to Clinical Laboratory Sciences
Types of staining techniques
Simple staining
(use of a single stain)
Differential staining
(use of two contrasting stains
separated by a decolorizing agent)
For visualization of morphological
shape & arrangement.
Identification
Visualization
of structure
Gram
stain
Acid fast
stain
Spore
stain
Capsule
stain

25. Introduction to Clinical Laboratory Sciences
Gram Stain:
It is the most important differential stain used in bacteriology because
it classified bacteria into two major groups:
b) Gram negative:
Appears red after Gram’s stain
Gram positive:
Appears violet after Gram’s stain

26. Introduction to Clinical Laboratory Sciences
Crystal violet ↓
Iodine
Alcohol
Safranin

27. Introduction to Clinical Laboratory Sciences
Gram –ve
E.coli
Gram +ve
S.aureus
Step 1: Crystal Violet
Step 2: Gram’s Iodine
Step 3: Decolorization
(Aceton-Alcohol)
Step 4: Safranin Red

28. Introduction to Clinical Laboratory Sciences
Gram’s +ve Bacteria
Gram’s -ve Bacteria

29. Introduction to Clinical Laboratory Sciences
Gram-positive bacteria
Have a thick peptidoglycan layer surrounds the cell.
The stain gets trapped into this layer and the bacteria turned purple.
Retain the color of the primary stain (crystal violet) after decolorization with alcohol
Gram-negative bacteria
have a thin peptidoglycan layer that does not retain crystal violet stain.
Instead, it has a thick lipid layer which dissolved easily upon decoulorization with Aceton-Alcohol.
Therefore, cells will be counterstained with safranin and turned red.

30. Types of culture media Based on their consistency a) solid medium
b) liquid medium (ex: Blood culture)
c) semi solid medium (for motility)
-Some media are used for bacterial growth, some for Bacterial differentiation and others for bacterial selection.
Macconkey agar which is selective for gram negative bacteria and differential them for lactose
Fermentation.

31. Introduction to Clinical Laboratory Sciences
Blood Culture
Blood is sterile in normal condition
Blood cultures are incubated and monitored electronically for bacterial and fungus growth.