1. Microbiology Introduction.ppt iuiu kc

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1. INTRODUCTION TO MICRO
BIOLOGY
MWAMBI BASHIR

2. Microbiology
•Microbiology - The science that studies very small
living things
•Usually requires a magnification tool – the microscope
•Some organisms are large though – Helminths –
worms
•Sub groups of Microbes we will study;
Bacteria
Archaea
Fungi
Protozoans
Algae
Viruses
Multicellular animal parasites – Helminths

4. Bacteria

5. Fungi

6. Protozoans
Giardia Ameba

7. Viruses
Bacteriophage Avian Flu

8. Helminth
Tapeworm Ascaris round worm

9. Thus;
•Various disciplines of study within
microbiology:
•Bacteriology, Mycology, Parisitology,
Immunology,
•Epidemiology,
•Biotechnology
•Virology
•Environmental Microbiology
•Bioremediation

10. Historical review of the Science of
Microbiology
Robert Hook – 1665 – Englishman, used a
primitive compound (two magnifying lenses)
microscope, reported that life’s smallest
units were little boxes – Cells, his work
started the process of the development of
the Cell theory of life

11. Hook’s microscope

12. Antoni Van Leeuwenhoek –1673 -
probably the first person to observe living
cells with a simple microscope, amateur
scientist, ground his own lenses and
described what we know today as bacteria –
rod shaped , spiral shaped , etc.
“animalcules”

13. Antoni Van Leeuwenhoek

14. Francesco Redi
Francesco Redi – 1668 – opposed the
prevailing theory of Spontaneous Generation,
maggots in meat , He used covered jars to
show that maggots came from flies –strong
evidence against spontaneous generation
Now we teach the theory of Biogenesis –
Life comes from Life
But issue of Spontaneous Generation was
actively believed for many more years

15. Francesco Redi

16. Edward Jenner
Edward Jenner is credited with first vaccine – in
epidemics of smallpox during the late 1700’s he observed
that milk maids didn’t get the disease, cattle had a similar
disease – cowpox, milk maids had cow pox lesions, but
not small pox, he purposefully took scrapings from cowpox
blister and scraped a 8 year old volunteer. With the
material – child got mild illness but not small pox,
Vaccination comes from Latin word “vacca” meaning cow.
Jenner laid the foundation for Pasteur’s later work with
other vaccinations.
(Vaccinia virus similar to Variola smallpox virus, today a
possible bioterror weapon – genetically engineered
variola?)

17. Jenner and vaccination

18. Louis Pasteur
Pasteur – French sceintist that dealt the death blow to the
spontaneous generation theory.
He devised the ingenious curved necked flasks that
prevented contaminated air from reaching boiled beef broth
– the broth remained uncontaminated even though
exposed to the air
He was very lucky – no endopores present, or it would
have failed
(resitant to boiling)

19. Louis Pasteur 2..
1. He developed process we call Pasteuriztion –
he heated wine to kill contaminating microbes –
cured sick wine (today we heat treatment to kill
pathogens in milk also)
2. He proved that fermentation was caused by a
microbe – yeast
3. He developed vaccines for rabies and anthrax.
Vaccines led to immunity to diseases that routinely
killed many people, used to help people long
before they understood how they even worked
(science of Immunology)
4. He began the revolution in science that led to
the Golden Age of
Microbiology (from 1857-1914)

20. Louis Pasteur 3..

22. Robert Koch
Robert Koch - Developed Koch’s postulates – important
technique for determining the
actual microbial cause agent of a disease – more later, German,
contemporary of Pasteur, several very important contributions
1. He discovered the tuberculosis bug (tubercle bacillus,
Mycobacterium tuberculosis)
2. He discovered the cause of anthrax (Bacillus anthracis) – from
blood of dead cattle, cultured bacteria in pure culture,
injected bacteria in live cattle and they died, then again cultured the
bacteria in pure culture. This led to the
establishment of a procedure for determining microbial
cause of disease (see p. ____-for modern application of Koch’s
postulates)

23. Koch’s postulates

24. Koch’s postulates
•1. The organism must be found on all the diseased
host tissue but not on the healthy host.
 
•2. The organism can be isolated from the host and
purified on artificial culture medium.
 
•3. The organism from pure culture, when
inoculated on the susceptible host must reproduce
the symptoms as in step 1.
 
•4. The organism can be re-isolated from the
artificially inoculated host on pure culture medium.
 

25. Limitations
 
•The cholera and Leprosy
•Vibrio cholerae, could be isolated from both sick and healthy
people, hence a negation of postulate #1.
•Leprosy negates postulate #2
•The limitations of Koch’s postulated were more prominent in
case of viral diseases which were not discovered at the time
these postulates were formulated.
•Most of the viruses which are present in living organisms do
not cause disease which is negation of postulate #1.
•For example, a poliovirus which is present in most of the
individual causes paralytic disease in only less than 1% of
infected individuals.

26. Limitations
 
•Similarly most of the viruses cannot be
isolated on pure medium or for which not
medium has been identified (Negation of
postulate #2 and #3).
•Thomas Rivers, “Father of modern virology”
also commented that in some instances
when the conditions are not met for Koch’s
postulated, then Koch’s postulated become
hindrance to work instead of assistance.

27. Modifications of Koch's Postulates
•Fredricks and Relman (1998) modified Koch’s postulates for
viruses and other nucleic acids (DNA/RNA) based pathogens.
•1. A nucleic acid sequence (DNA/RNA) of known pathogen
should be found associated in most of the cases with a disease
which can found in those organs or gross anatomical sites which
are having symptoms of the disease.
•2. Pathogen-associated nucleic acid sequences may or may not
be present in fewer numbers from the host or tissues without
disease.
•3. The copy number (count) of the pathogen-associated nucleic
acid sequences should decrease or become undetectable in
case of resolution of disease. With clinical recurrence, the case
will be vice versa.

28. Modifications of Koch's Postulates
•4. In case of association of the nucleic acid sequences with the tissue
before disease development or when sequence copy number correlates
severity of disease or pathology; then the sequence-disease relationship
is more likely to be causal relationship.
•5. The nature of the microorganism inferred from the available sequence
should be consistent with the known biological characteristics of that
group.
•6. The relationship between the sequence and tissue should be tried to
establish at the cellular level; efforts should be made to demonstrate the
hybridization of the microbial sequence to the areas of tissue pathology
and to visible microorganisms or to areas where microorganism are
thought to be involved. These sequence based forms of evidences for
microbial causation should be reproducible.

29. Koch’s and Pasteur’s work helped
establish the “Germ Theory of Disease”
- that
microorganisms cause disease (in
people, animals, and even plants)

30. Microbiology – Chapter 1
Iwanowski 1892 - Discovered that plant disease
can be caused by small organisms that
were so small they passed through filters , Tobacco
mosaic virus (TMV) was later
identified as the cause - beginning of virology
(Today we have discovered new and
weird things like viroids, prions) See next slide

31. Microbiology – Chapter 1

32. Microbiology – Chapter 1
Paul Ehrlich, German doctor, wanted to find a
“magic bullet” an agent that would kill
the disease agent without hurting the patient (see
the “Coming plague” video, part 1)
1. Developed Salvarsan, “salvation from
syphilis”agent
2. This was an arsenical – arsenic compound, that
was effective against syphilis
Antimicrobial agent, medicine to treat a
microbial disease, it was chemical –
chemotherapy

33. Microbiology – Chapter 1
•Syphilis spirochete: T. pallidum Paul Ehrlich

34. Microbiology – Chapter 1
Joseph Lister – 1860’s, English surgeon that
applied ideas of the germ theory to surgery,
remembered the work of Semmelweis in Hungary
in the 1840’s, if a Dr. would wash their hands
childbed fever was prevented. He knew that
phenol would kill bacteria; put 2 and 2 together
and treated wounds with phenol - and no infection
(phenol is the basic agent of today’s – Lysol)
1. First antiseptic use in surgery, chemicals used
as agents on tissue before surgery
(tissue treated with an antimicrobial agent –
antiseptic, betadine) disinfectants are
chemicals, used on a surface
2. Also proved that microbes cause surgical
infections (today’s scourge –MRSA)

35. Semmelweis

36. Lister
•Antisepsis in surgery

37. In Uganda
•https://www.nlm.nih.gov/exhibition/cesarea
n/part2.html

38. Microbiology – Chapter 1
Alexander Fleming - Scottish physician and bacteriologist - 1928
Observed mold growing on a bacteria culture, there was a ring of
clearing around the mold where the bacteria didn’t grow, the mold
was later found to be a Penicillium species and the naturally
secreted chemical was called penicillin, an antibiotic
1. Antibiotics are natural agents
2. Synthetic drugs are chemicals produced in labs (sulfas)
3. Problems with them - toxicity, resistance, allergic reactions
4. Fleming’s work - shelved until early WWII, sulfas were failing,
needed penicillin to cure battle field wounds
5. Now have thousands of antibiotics and synthetics (and a
significant problem – resistance)

39. Flemming and Penicillium

40. Microbiology – Chapter 1
Salk - Polio vaccine, 1950’s polio was a scary
epidemic, Salk developed a vaccine by
treating the virus with formalin (IPV) inactivated
polio virus
Sabin 1963 live Polio virus vaccine, attenuated –
altered virus, OPV-oral polio vaccine
The work done on polio revolutionized the science
of virology and we are seeing
the results today in advances with Hepatitis and
HIV viral infections - tissue
culture and other techniques

41. Avery and Macleod, DNA is genetic material

42. Watson and Crick, DNA, 1953

43. DNA Double helix
•Double Helix

44. Salk; IPV

45. Sabin, OPV

46. Microbiology – Chapter 1
Jacob and Monod – 1965 Did research on RNA and
protein synthesis in bacteria - last
necessary step in understanding how genetics works on a
cellular level (Replication,
Transcription, Translation – protein synthesis – expression
of traits)
Modern science thrives today only on the laid foundation of
thousands of men and
women who did mundane routine and often boring lab
science. Don’t forget that we are
here today because we stand on the shoulders of Giants –
who were people just like you
and me. (Who are the Giants today? CDC, USAMRID,
young Joe or Mary the graduate
student?, maybe you?)

47. Microbiology – Chapter 1

48. The Classification of Living
Things
•Living organisms are assigned to groups
based upon their similarities.
•Systematics is the discipline of
identifying and classifying organisms.

49. Domains
•The highest – largest category, recent addition
•3 domains
–1. Archaea – ancient “bacteria”, unicellular like
bacteria, also simple cell structure (prokaryote – no
nucleus) but have distinct metabolism (chemistry)
allowing them to exist in “extreme” environments
–2. Bacteria – unicellular, prokaryote, found
everywhere (Old kingdom name – Monera)
–3. Eukarya – unicellular to multicellular, complex and
organized cells with nuclei and organelles
(mitochondria)

50. Domain Archaea
•Archaea are single-
celled organisms that
lack a membrane-
bound nucleus. -
Prokaryote
•Archaea can be found
in environments that
are too hostile for
other life forms.

51. Domain Bacteria
•Bacteria are single-
celled organisms that
lack a membrane-
bound nucleus.
(Prokaryote also)
•Bacteria are found
almost everywhere on
the planet Earth.

52. Domain Eukarya
•The cells of all eukaryotes have a membrane-
bound nucleus. Members of the Domain
Eukarya are further categorized into one of
four Kingdoms. (know these kingdoms)

53. Microbiology
•Check your notes; Older 5 kingdom
scheme is still widely used
•Monera – bacteria (Prokaryotic)
•Protista – Protozoans (Eukaryotic)
•Fungi - yeast, molds, etc. (Eukaryotic)
•Plant – photosynthetic producers
(Eukaryotic)
•Animals – heterotrophic consumers
(Eukaryotic)

54. Categories of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

55. Categories of Classification
Domain - Dumb
Kingdom - King
Phylum - Philip
Class – Came
Order - Over
Family - For
Genus - Good
Species - __
Spaghetti?

56. Categories of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Least inclusive
Most inclusive

57. Categories of Classification

58. Scientific Names
•Binomial (two name) Genus first and first letter
capitalized, then species not capitalized. If
written or typed – either underline or italicize
–Genus name, species name
–Homo sapiens - italicized
–Homo troglodytis (Your EX?) – underlined
–Canis familiaris – Your puppy (except poodles)
–Felis domesticus – Your Kitty (some strange people
have to have Felis leo or Felis tigris)
–Canis latrans – Invites your kitty over for lunch
–Canis lupus - ____________? guess

59. Know for test
•3 domains Archaea, Bacteria, Eukarya
•4 Eukarya Kingdoms
–Protista – Protozoans like Ameba and
Paramecium (producers and consumers)
–Fungi – yeasts, molds, mushrooms
(consumers)
–Plants – complex producers, trees, grasses
–Animals – complex consumers

60. Classification of Bacteria
•Somewhat different: a clinical rapid ID is
often important when trying to find
causative agent of a disease
•Bergey’s manual: Manual is in lab for a
reference when doing unknown
•Developed on 1940’s for grouping bacteria
according to standard diagnostic lab
techniques available at the time (such as
Grams stain)

61. Classification of Bacteria
•Gram +cocci Gram -
bacilli

62. Classification of Bacteria
•
Gram - Spirochete Gram + bacilli

63. Classification of Bacteria
•The manual divides bacteria into 4 groups
or divisions on the basis of their Cell Wall
–1. Gram + (stain violet)
–2. Gram - (destain, and are counterstained
pink or reddish color)
–3. Bacteria that lack a cell wall (mycoplasma)
–4. organisms that have a cell wall lacking
“peptidoglycan” (archaeobacteria – Now
called “Archaea”

64. Classification of Bacteria
•More modern methods now used:
•1. DNA studies, genomics, gene probes
•2. using Bacterial viruses “bacteriophages”
•3. Serology – antibody – antigen reactions (like
blood typing)
•Examples: Salmonella typhi
•Salmonella typhimurium
•Azotobacter vinelandii 12837
•E. coli 0157H7 nasty strain of E. coli