Microbiology is the study of microorganisms and their interactions with other organisms. This document discusses different types of symbiotic relationships between microorganisms such as mutualism, commensalism, neutralism, and parasitism. It also describes the indigenous microbiota that naturally inhabit different parts of the human body like the skin, gastrointestinal tract, and genitourinary system. These microorganisms play an important role in processes like nutrient cycling and soil fertility.

2. • it is
the scientific study
of interactions
among organisms and
their environment,
such as the
interactions organis
ms have with each
other and with their
abiotic environment.

3. • Is the study of numerous interrelationships between
microorganisms and the world around them;
how microbes interact with
other microbes
how microbes interact with
organisms other than
microbes
and how microbes interact
with the non- living world
around them

5. (Symbiotic Relationship)
• Is defined as the living
together in more or less
intimate association or close
union of two dissimilar
organisms
• The organisms that live
together in such relationship
are called Symbionts.

6. Neutralism
• Is used to describe a symbiotic
relationship in which neither
symbionts is affected by the
relationship.
• Reflects a situation in which
different microorganisms occupy
the same ecological niche but
have absolutely no effect on
each other.

7. Commensalism
• an association between two
organisms in which one
benefits and the other
derives neither benefit nor
harm.
• Ex.
Human and indigenous
Microflora

8. • symbiotic relationship between individuals of
different species in which
both individuals benefit from the association.
• In this type of symbiosis, both organisms of
different species rely on one another
for nutrients, protection and other life
functions, hence, they are usually found living
in close proximity.

9. • Example:
Eschericha coli,
which obtains
nutrients from food
materials ingested by
the host and
produces vitamins
(such as Vitamin K)
which are used by the
host.

10. Parasitism
• parasitism, relationship
between two species of
plants or animals in which
one benefits at the expense
of the other, sometimes
without killing it.

11. Synergism
(Synergetic Infection)
• the interaction or
cooperation of two or
more organizations,
substances, or other
agents to produce a
combined effect greater
than the sum of their
separate effects.

12. Indigenous
Microflora of Humans

13. Indigenous Microflora or Indigenous
Microbiota
• “normal Flora”
• Includes all the microbes (bacteria, fungi,
protozoa and viruses) that reside on or within
that person.

14. • It has been estimated that our bodies are
composed of about 10 trillion cells (including
nerve cells, muscle cells, epithelial cells, etc.),
and that we have about 10 times that many
microbes that live on and within our bodies
(10x10 trillion = 100 trillion)
• It has also been estimated that our
indigenous microflora is composed of
between 500 and 1000 different species.

15. Eyes and
Ears
Skin
Mouth and
upper
Respiratory
tract
Gastrointestinal
tract
Genitourinary tract
(vagina, urethra)

16. Microflora of the skin

17. • The resident microflora of the skin consists
primarily of bacteria and fungi – approximately
30 different types.
• The most common bacteria on the skin are
species of:
- Staphylococcus,
- Micrococcus,
-Corynebacterium,
- Propionibacterium,-P.acnes- causes acne.
-Brevibacterium,
-and Acinetobacter.

18. •
•
•
•
•
•
•
•
•
•
•
•
Staphylococcus aureus
Acinetobacter spp
Bacillus spp
Candida albicans
Corynebacterium spp
Corynebacterium
parvum
Demodex folliculorum
Enterobacter cloacae
Epidermophyton
floccosum
Micrococcus spp
Micrococcus luteus
Mycobacterium spp
•
•
•
•
•
•
•
•
•
•
•
•
Neisseria spp
Peptostreptococcus spp
Malassezia ovale
Propionibacterium spp
Propionibacterium
acnes
Pseudomonas
aeruginosa
Sarcina spp
Staphylococcus aureus
Staphylococcus
epidermidis
Staphylococcus
haemolyticus
Streptococcus viridans
Trichophyton spp

20. Microflora of the eyes and ears

22. Microflora in the
Gastrointetinal
Tract

23. Binomial name
Location
Achromobacter spp
Acidaminococcus fermentans
Acinetobacter calcoaceticus
Actinomyces spp
Actinomyces viscosus
Actinomyces naeslundii
Aeromonas spp
Aggregatibacter actinomycetemcomitans
Anaerobiospirillum spp
Alcaligenes faecalis
Arachnia propionica
Bacillus spp
Bacteroides spp
Bacteroides gingivalis
Bacteroides fragilis
Bacteroides intermedius
Bacteroides melaninogenicus
Large intestine, small intestine (Ileon)
Large intestine
Large intestine
Amygdala
Mouth
Mouth
Large intestine, small intestine (Ileon)
Mouth
Feces
Large intestine, small intestine (Ileon)
Mouth
Large intestine
Mouth, amygdala
Mouth
General distribution
Mouth
Mouth, feces
Bacteroides pneumosintes
Pharynx

24. Microflora in the Respiratory Tract

25. Binomial name
Acinetobacter spp
Burkholderia cepacia complex
Campylobacter sputorum
Candida albicans
Cardiobacterium spp
Chlamydophila pneumoniae
Citrobacter freundii
Eikenella corrodens
Haemophilus spp
Haemophilus parainfluenzae
Haemophilus paraphrophilus
Kingella spp
Kingella kingae
Moraxella spp
Moraxella catarrhalis
Mycoplasma orale
Mycoplasma pneumoniae
Neisseria spp
Neisseria cinerea
Neisseria elongata
Location
Nasopharynx
Lung
Nasopharynx
Pharynx
Nose
Lung
Throat
General distribution
Nasopharynx
Pharynx
Pharynx
Upper respiratory Tract
Upper respiratory Tract
Nasopharynx
Nasopharynx
Oropharynx
Respiratory epithelium
Nasopharynx
Nasopharynx
Pharynx

27. Microflora in the Genitourinary
Tract

28. Binomial name
Acinetobacter spp
Bacteroides spp
Bifidobacterium spp
Location
Anterior urethra, vagina
External genitalia
Vagina
Candida albicans
Anterior urethra, external genitalia, vagina
Chlamydia trachomatis
Urethra, vagina, fallopian tubes, prostate gland
Clostridiums pp
Vagina
Corynebacterium spp
Anterior urethra, external genitalia, vagina
Enterobacteriaceae
Anterior urethra, external genitalia, vagina
Neisseria gonorrhoeae
Urethra, vagina, prostate gland
Streptococcus viridans
Anterior urethra, external genitalia, vagina
Eikenella corrodens
Streptococcus anginosus
Staphylococcus aureus
Gardnerella vaginalis
Mycoplasma hominis
Mobiluncus curtisii
Mobiluncus mulieris
General distribution
General distribution
Perineum
Female reproductive system
Cervix, vagina
Vagina
Vagina

29. • Genitourinary infections fall into two main categories: (1)
primary infections due to sexually transmitted pathogenic
microorganisms and (2) infections due to members of the
resident flora. Genital infections are uncommon in
children and increase dramatically in sexually active
adults, in whom sexually transmitted diseases are the
second most prevalent group of reportable communicable
illness in North America. Sexually transmitted pathogens
include parasites (Trichomonas vaginalis), bacteria
(Treponema pallidum, Neisseria gonorrhoeae, Chlamydia
trachomatis, Haemophilus ducreyi), and viruses (Herpes
simplex virus, human papillomavirus, human
immunodeficiency virus). Genital infections due to the
fungus Candida albicans or to members of the
endogenous bacterial flora (Bacteroides fragilis and
members of the family Enterobacteriaceae) are not known
to be sexually transmitted. Bacterial vaginosis occurs when
the balance of vaginal flora is upset.

30. • The urinary tract and urine are normally
sterile. Numerous mechanical and biologic
processes ensure that microorganisms do not
enter the urinary tract. Women are more
susceptible to urinary infections because the
female urethra is short and because the area
around the urethral opening is colonized with
potential pathogens (e.g. E coli and E faecalis).

31. BENEFICIAL EFFECTS OF
INDIGENOUS FLORA

33. Microbial antagonism
• “microbes versus microbes”
• Our indigenous microflora serve a beneficial
role by preventing other microbes from
becoming established in or colonizing a
particular anatomic location
• Microbial antagonism is a property that
enables a microorganism to kill, injure or slow
down the growth of a different microorganism.
Bacterial flora benefits the microbial
antagonism host. It does this by preventing
overgrowth of harmful organisms.

34. Opportunistic Pathogen
• an organism that exists harmlessly as part of
the normal human body environment and
does not become a health threat until the
body's immune system fails.
• Organisms that are hanging around, waiting
for the opportunity to cause infections

37. • Agricultural microbiology is a branch
of microbiology dealing with plant-associated
microbes and plant and animal diseases. It
also deals with the microbiology of soil
fertility, such as microbial degradation of
organic matter and soil nutrient
transformations.

38. Microbes and the Cycles of
Elements of Life

39. The Nitrogen Cycle

40. CO2 Cycle

41. Soil Microorganisms

42. Bacteria
• more dominant group of microorganisms in
the soil and equal to one half of the microbial
biomass in soil. Population 100,000 to several
hundred millions for gram of soil Autochthnous - Zymogenous groups.
Majority are Heterotrophs. (Common soil
bacteria - Arthrobacter, Bacillus, Clostridium,
Micrococcus).

43. • - intermediate group between bacteria
and fungi. Numerous and widely
distributed in soil. Abundance is next to
bacteria. 104 - 108/g soil. 70% of soil
actinomycetes are Streptomyces. Many
of them are known to produce
antibiotics. Population increases with
depth of soil.

44. Fungi
• More numerous in surface layers of wellaerated and cultivated soils-dominant in acid
soils. Common genera in soil are Aspergillus,
Mucor, Penicillium Trichoderma, Alternaria,
Rhizopus. Algae – found in most of the soils in
number ranges from 100 to 10,000 per g

45. • Protozoa: Unicellular – population ranges
from 10,000 to 100,000 per g of soil. Most of
the soil forms are flagellates, amoebae or
ciliates. Derive their nutrition by devouring
soil bacteria. Abundant in upper larger of the
soil. They are regulating the biological
equilibrium in soil.

46. Importance of soil microorganisms
• Involved in nutrient transformation process
• Decomposition of resistant components of plant and
animal tissue
• Role in microbial antagonism
• Participate in humus formation
• Predator to nematodes
• Surface blooming reduces erosion losses
• Improves soil structure
• Maintenance of biological equilibrium
•