2. Microbiology is the study
of organisms which can
not be seen with the
help of naked eye.
The term microbiology
was introduced by the
French chemist Louis
Pasteur.
Louis pasteur
3. Robert Koch is considered as father of
microbiology.
His first contribution was demonstration
of mode of growth of
bacillus anthracis ( causative agent of
anthrax).
4. In 1882, Koch
discovered
tubercle bacillus
and in 1883 the
Vibrio cholerae .
Robert Koch
5. After identification and confirmation of
bacteria as causative agents of human
diseases, efforts were made
to develop effective agents against them.
Pioneer work was done by Paul Ehrlich
who is described as the father of
chemotherapy.
6. In 1910, Ehrlich
successfully treated
syphilis using
compound
'606'’which he
named Salvarsan.
Also called
Arsphenamine
7. Medical microbiology is a branch
of medical science concerned with the
prevention, diagnosis and treatment of
infectious diseases.
Infection is the invasion of an
organism's tissues by disease causing
organisms (Microorganisms) and their
multiplication.
8. Microorganism:
The organism which causes disease or
pathogenesis is called microorganism.
The agents of human infectious diseases
belong to five major groups:
1.Bacteria.
2. Viruses
3. Fungi.
4.Protozoa.
5.Helminths.
9. Eukaryotes & Prokaryotes
Cells have evolved into two different
types, eukaryotic and prokaryotic
Fungi, protozoa and helminths are
eukaryotic, whereas bacteria are
prokaryotic.
10. The bacteria belong to the prokaryote
kingdom.
The fungi and protozoa belong to
kingdom of protists or protista
The helminths (worms) are classified in
the animal kingdom.
Viruses are not cells but behave so
inside host cell.
11. Helminths and the protozoa together are
commonly called parasites.
Important Features of these
organisms:
One main difference is that bacteria,
fungi, protozoa, and helminths are
cellular, whereas viruses are not.
This distinction is based mainly on
12. Structure. Cells have a nucleus or
nucleoid( in case of bacteria). It Is
surrounded by cytoplasm.
Viruses have genetic material (either
DNA or RNA) but no cytoplasm.
Method of replication. Cells replicate
either by binary fission or by mitosis.
13. Prokaryotic cells, e.g., bacteria, replicate
by binary fission, whereas eukaryotic
cells replicate by mitosis.
In contrast, viruses must replicate within
host cells because they lack protein-
synthesizing and energy-generating
systems.
14. Nature of the nucleic acid.
Others contain both DNA and RNA,
whereas viruses contain either DNA or
RNA but not both.
15. Biologic Relationships of Pathogenic
Microorganisms.
Kingdom Pathogenic
Microorganisms
Type of Cells
Animal Helminths Eukaryotic
Protista Protozoa Eukaryotic
Fungi Eukaryotic
Prokaryote Bacteria Prokaryotic
Viruses Non-cellular
16. Characteristics of Prokaryotic and Eukaryotic Cells.
Characteristic Prokaryotic
Bacterial
Cells
Eukaryotic
Human
Cells
DNA within a nuclear membrane No Yes
Mitotic division No Yes
DNA associated with nucleoproteins No Yes
Chromosome number One More than
one
Membrane-bound organelles, such
as mitochondria and lysosomes
No Yes
Size of ribosome 70S 80S
17. Virology:
It is the study of viruses regarding their
structure and diseases caused by
them.
Viruses are very small particles
Not visible by light microscope.
Electron microscope is needed to see
them.
18. Viruses can pass through filters.
Viruses may be plant viruses or animal
viruses.
The animal viruses affect the animals
including man.
Certain viruses like that of Rabies, Yellow
fever etc. are transmitted to human
beings from infected animals.
19. These viral conditions are called as
zoonoses (singular= zoonsis).
Viruses are classified as
1. DNA viruses
2. RNA viruses
Enveloped
Non enveloped
20. Parasitology:
It is the study of structure of parasites
and diseases caused by parasites.
Parasites occur in two distinct forms:
single-celled protozoa and multicellular,
metazoa called helminths or worms.
21. Host:
A host is an organism that harbors a
microorganism (parasite).
A host can be
1. Primary host
2. Secondary host.
A primary host or definitive host is a host in
which the parasite reaches maturity and, if
possible, reproduces sexually.
22. A secondary host or intermediate
host is a host that harbors the
parasite only for a short transition
period, during which (usually) some
developmental stage is completed.
23. A reservoir host or reservoir can
harbour a pathogen indefinitely with no
ill effects.
A single reservoir host may be
reinfected several times.
24.
25. Mycology:
The study of fungi is called Mycology,
and the diseases they cause are called
mycoses.
Fungi exist as unicellular or
multicellular organisms.
26. There are two types of fungi:
1. Yeasts
2. Molds.
Yeasts grow as single cells and
reproduce by asexual budding.
Molds grow as long filaments
(hyphae) and form a mat
(mycelium).
27. So molds are multicellular.
Reproduce asexually or sexually both.
