Microbiology

1. Lt Col Nuruzzaman
DCP,MCPS,FCPS( Haematology),
Graded Spl in Pathology,
CMH,Chittagong.

2.  MICROBIOLOGY: Science dealing with
detailed study of microorganisms
 MICROORGANISM: Small living organism
beyond the vision of naked eye

3.  ORIGIN OF EARTH: 4.6 X 109 years
 ORIGIN OF LIFE: 1.5 X 109 years
HISTORY

4.  1590 – First compound light microscope
Zacharias Janssen

5.  1676 –first observation of bacteria
“animalcules”
Anton Von Leeuwenhoek
(a Dutch draper )

6.  1796 – First vaccine (smallpox)
Edward Jenner

7.  1857 – Germ Theory of Disease
Louis Pasteur (French chemist)

8.  1867 Antiseptic Surgery
Joseph Lister (British army surgeon):"
Father of antiseptic surgery”,

9.  1884 ‘Koch’s Postulates of Disease Transmission’
Robert Koch (German army physician, Father of
modern microbiology),

10.  The organisms should be consistently associated
with diseases & should be found in the lesions
observed
 Microorganisms should be grown in pure culture in
vitro
 When such pure culture is inoculated, typical
disease must result
 Microorganisms must again be isolated from the
lesions of such experimental animals
Exceptions:
v Treponemma pallidum & M. leprae can’t be grown in
artificial media
v Gonococcus has no animal models

11.  1885 - Vaccine against
Rabies
Louis Pasteur

12.  Genetic engineering
 Cloning
 Human Genome Project
 Biotechnology
 Who knows what is next?

13. B
D
C
A : Non-living matters B : Plants C : Animals D : Microbes
A

14.  BACTERIA: Unicellular microorganism having
prokaryotic type of cellular organization
 VIRUS: Extremely small, obligate intracellular
infectious agents containing either DNA or RNA as
their genome
 FUNGUS: Unicellular or multicellular,
nonphotosynthetic eukaryote having rigid cell wall.
 PROTOZOA: Unicellular, nonphotosynthetic, microbial
eukaryote belonging to parasite.
 SLIME MOULDS: Microbial eukaryotes, which at one
stage of their life cycle contain an amoeboid mass of
cytoplasm called Plasmodium.

15.  Virus - 10 →1000 nanometers *
 Bacteria - 0.1 → 5 micrometers **
(Human eye ) can see .1 mm (1 x 10 -3 m)
* One billionth or 1 x 10 -9 m
** One millionth or 1 x 10 -6 m

16.  Compound light Microscope
- live specimens
- 1,000 mag. or less
 Electron Microscope
- non-living specimens
- > 1,000 X mag.
 Incubator – keep microbes warm for
growth

17.  Staining – to better see structures
 Microbial Culture - growing the wee
beasties
 Container for microbe culture
- usually Petri dish
 Culture media
- Food for the microbes
- E.g. Agar – (from red algae)
- Others such as nutrient broths

18. 1. Primary microscopy from the specimen/sample
2. Inoculation of suitable medium/media with the sample.
*MEDIUM : Artificial food for the growth of bacteria. It may
be solid (to study the morphology of colony), semisolid (To
detect motility) or liquid (To yield faster growth)
3. Analysis of the colonial morphology of the responsible
pathogen
4. Biochemical and immunological tests to identify the organism
5. Drug sensitivity test

19.  Linaenian system : (Binominal
classification) Genus & Species
 Hierarchical system : Phyla, Class, Order,
Family, Genus, Species etc

20. MICROORGANISM
Prokaryotes Eukaryotes Sub
cellular
1. Bacteria 1. Algae 1. Virus
(Incl Chlamyda,
mycoplasma
& Rickettsia)
2. Archaebacteria 2. Fungi 2. Viroids
3. Cyanobacteria 3. Slime moulds 3. Prions
4. Protozoa 4. Virinos

21. 1. According to morphology :
 Cocci or dot-shaped
 Bacilli or rod-shaped
 Vibrios or comma-shaped e.g
V.cholerae
 Spirillar or twisted e.g Spirochaetes
(T. pallidum)
 Cocco-bacilli e.g Brucella, Bordetella

24. Gram +ve cocci Gram –ve cocci
Gram + ve bacilli
Gram –ve bacilli

25. 2. According to Gram,s Staining :
 Not stainable : Spirochaetes, Chlamyda,
Rickettsia etc
 Stainable:
 Gram positive bacteria
 Gram negative bacteria

26. 3. According to both morphology & Gram’s
staining:
a. Gram positive cocci
 Staphylococcus
 Streptococcus
 Pneumococcus (S. pneumoniae)
 Enterococcus (Grows in MacConkeys agar)
 Micrococcus (Strict aerobe)
 Peptostreptococcus (Strict anaerobe)

27. b. Gram positive bacilli
 Corynaebacterium (C. diphtheriae)
 Lactobacillus (Dental carries)
 Bacillus
 Clostridia (Strict anaerobe)
 Listeria (L. monocytogenes-Neonatal meningitis)
 Erysepelothrix
 Eubacterium (Strict anaerobe)
 Bifidobacterium (Strict anaerobe)
 Propionibacterium (Strict anaerobe

28. C. Gram negative cocci
 Neisseria ( N. gonorrhoeae, N. meningitidis)
 Branhamella
 Moraxella
 Veillonella
 Acinetobacter

29. D. Gram negative bacilli
 Escherichia coli*
 Salmonella
 Shigella
 Klebsiella*
 Enterobacter*
 Proteus
 Pseudomonas
 Citrobacter
 Serretia
 Edwardsiella
*Rapid lactose fermenters

30. 4. According to the requirement of O2 and CO2:
 Aerobes & facultative anaerobes( Grow both in
presence & in absence of O2)
 Strict aerobes (Grow only in presence of O2)
 Strict anaerobe (Grow only in absence of O2)
 Microaerophilic : (5-10 % O2)
 Capnophilic : (5-10 % CO2)

31. 6. Numerical classification
7. Molecular classification: Based on :
 DNA content
 DNA homology
 Ribotyping

32. Points Prokaryotes Eukaryotes
Nucleus
• Nuclear membrane
• Chromosome
• Nucleoli
• Cell division
Absent
Single chromosome
Absent
Binary fission
Present
Multiple chromosome
Present
Mitosis
Cell wall peptidoglycan
Present (Except
mycoplasma)
Absent
Cell membrane containing
Sterol
No (Except
mycoplasma)
Yes
Cytoplasm
Membrane-bound organelles
(Mitochondria, Golgi body, ER
etc)
o Ribosomes
o Protoplasmic streaming
Absent
70 s
Absent
Present
80 s
Present