Download Microbiology of environment

Chair of Medical Biology, Microbiolog
Virology, and Immunology
MICROBIOLOGY OF
ENVIRONMENTS.
MICROBIOLOGY OF
HUMAN BODY
Ecology (oicos – house, hold, logos doctrine) is the study of relationships
among organisms and their environment.
The microecology is the science about
places of invading of microorganisms and
their ecological links.
In microbial ecology the main concepts are:
population - an elementary evolutional
unit (structure) of a definite species;
biotope - site, habitation of a population,
for parasites - place of their localization in
an organism;
In microbial ecology the main concepts are:
microbiocenosis - microbial assemblage,
association, that is collection of populations
of different species of microorganisms,
which dwell (live) in the defined biotope
(for example, in an oral cavity, reservoir);
ecosystem - system, in which enters a
biotope and microbiocenosis.
Types of symbioses:
Neutralism - the populations,
existing in one biotope do not stimulate
and do not oppress each other.
Mutalism exists when organisms live
in an obligatory but mutually beneficial
relationship.
Nitrogen fixing bacterium
Types of symbioses:
Commensalism - such relationship, at
which the member called the commensal
receives benefits, when its coinhabitant is
neither harmed nor benefitted.
The structural interactions of the bacteria
probably are a reflection of the complex metabolic
interactions that are known to occur between
different teeth plaque microorganisms.
For example: the production of succinic acid
from Campylobacter species that is known to be
used as a growth factor by Porphyromonas
gingivalis. Streptococcus and Actinomyces species
produce formate, which may then be used by
Campylobacter species. Fusobacterium species
produce both thiamine and isobutyrate that may be
used by spirochetes to support their growth.
Types of symbioses:
Antagonism - oppression of one population another. The microbes – antagonists
produce antibiotics, bacteriocines, fatty acids,
which cause destruction of bacteria or delay
their reproduction.
Bacterial antagonism
Types of symbioses:
Parasitism - such kind of symbiosis, at which
one population (parasite) brings harm to the host,
and for itself has a benefit.
Ricketsia – intracellular
parasites
The soil is the major environment for a
habitation of microorganisms.
The amount of bacteria in one gram of soil
can be very great – from 200 millions up to 10
billions.
The most surface sphere of soil (crust by
width of 2-3 mm) is very poor by microorganisms. A desiccation and the solar rays perniciously influence them. The ground mass of
bacteria is on depth 10-20 cm. On depth of 1,52 m of untouched ground the microbes do not
meet almost.
The microflora of soil includes hundreds of
species of bacteria, viruses, protozoa,
actinomyces and fungi. It is various species of
putrefactiving, nitrifying, denitrifying, nitrogenfixing bacteria. The most often inhabitants of soil
are the representatives of genus Azotobacter,
Nocardia, and Clostridium. Many bacteria of
genus Rhisobium, Nitrosomonas, Nitrosospira,
Nitrobacter, Pseudomonas are very often found.
Almost always there are denitrifying bacteria
(B.denitrificans), ammonifying microbes
(Urobacillus pasteurii, Urobacillus leybii),
numerous iron bacteria and sulphur-bacteria.
All of them play the great role in a
turnover of materials in a nature, improve
productivity of our fields, provide life on
the Earth. The microorganisms of soil take
an active part in all processes of transformation of materials and energy: synthesis
of a biomass, biological nitrogen fixation,
fermentation, corruption, denitrification of
the cycle sulfur, iron lactas, phosphorum,
carboneum and other elements.
Carbon cycle
Nitrogen
cycle
Sanitary - indicative bacteria of soil are:
Escherichia coli,
Streptococcus faecalis,
Clostridium perfringens
termophilic bacteria.
A degree of fecal contamination of soil is
determined on presence and quantity (amount) of
first three species.
More exact rating is manufactured at
definition coli - index, that is amount of
bacteria E.coli in 1 g of soil.
Also general microbial number (GNM) –
quantity (amount) of all saprophytic
bacteria in 1 g of soil is examined.
The soil is considered pure, if its coliindex does not exceed 2000, and the
quantity of termophilic bacteria is in limits
100 - 1000.
Under the epidemic indications soil also
is inspected on presence in it pathogenic
bacteria (Salmonella, Shigella, C. tetani,
C. botulinum, C. perfringens, B. anthracis
and others).
Water is a natural medium of a
habitation of various microorganisms. In
sweet and salty waters representa-tives of
all groups of bacteria are found Protozoa,
Fungi, Viruses, Water - plant.
The microflora of reservoirs consists of two
groups of microbes:
autochtonal (or aqueous) microorganisms /
permanently live and are multiplied in water/.
It is more often such species: Micrococcus
candicans, M. roseus, Sarcina lutea, Bacterium
aquatilis communis, Pseudomonas fluorescens.
The anaerobes represent by species
Clostridium, Bacillus cereus, B. mycoides.
allochtonal (brought from the outside).
The microbial composition of water is in the
large degree mirrors a soil microflora. A major
factor, which determines quantity of microbes in
water is presence in it of necessary nutritious
materials, that are various biological matters.
Main path of microbial contamination of water
is penetration of unpurified waste from sewage of
the populated area. Therefore, the more water is
polluted with similar organic matters, there are
more in it of microorganisms.
Zones of water clearness
Polisaprogenic zone is the zone of strong
contamination. It contains many organic matters and
almost there is no oxygen. The quantity of bacteria in
1 ml of water reaches one million and more.
Mesosaprogenic zone is the zone of moderate
contamination(pollution)). In it the nitrifying and
aerobic bacteria prevails. The total number of
microorganisms compounds hundreds of thousand in
one ml.
Oligosaprogenic a zone (zone of pure water). The
quantity of bacteria changes from 10 up to 1000 in
one ml.
Sometimes the pathogenic bacteria in
water can get and they will be saved for
some time: S. typhi, V. cholerae,
. S. dysentеriae. Often various viruses are
found: Polioviruses, Hepadnaviruses,
Enteroviruses and others. The pathogenic
microorganism getting in reservoirs,
abundant in a zone of strong
contamination, gradually die in a zone of
moderate contamination. They are almost
not found in oligosaprogenic zones.
Water plays very important role in
epidemiology of many contagious diseases
(typhoid, dysentery, cholera, poliomyelitis,
virus
hepatites and others). The causative
.
agents of these illnesses are discharged with
feces of the patients and carriers. Together
with sewage they enter in water of open
reservoirs. In summer time some bacteria,
including Vibrio cholerae, can even multiply.
To catch it is possible through ice, in which the
pathogenic bacteria can be saved during
several weeks and even of months.
In many countries for a rating of quality of potable
water the normative documents or state standards are
taken. Microbiologic index of safety of potable water
are the following:
1. Common microbial number in one ml of water no more than 100.
2. Number of bacteria of intestinal rod group (coliindex) in 1000 ml of water - no more than 3.
3. Index of fresh fecal contamination, that is
quantity(amount) E.coli in 1000 ml of water - absence.
4. Quantity coli-phages (number of colony-forming
units) in 1000 ml of water - absence.
5. Besides in 25 litters of potable water pathogenic
Protozoa (cyst of lamblia, dysenteric amebas, balantidia)
and ovum of helmints there should be absent.
Common microbial number of water is examined by
inoculation of 1 ml of water in melted and refrigerated up
to 50 C in agar in Petri dishes.
Coli-index is determined by a method of membrane
filters or fermentation tests.
Microflora of air
Air for microorganisms is less favorable
environment, than soil and water. There
are almost no the nutritious materials
necessary for reproduction of bacteria.
Desiccation and the ultraviolet rays
operate perniciously on microorganisms.
Nevertheless, many microbes in air can be
saved more or less long time.
Main sources of microbial air pollution
is the soil, water and man.
The composition of a microflora of air is
very various. It depends on cleanness of air,
deposits, temperature, humidity, climate
and geographical conditions. Than it is
more in air of a dust, smoke, soot, the more
microorganisms. Vice-versa, above
mountains, seas, oceans and woods, where
air is pure, it is not enough of microbes. In
open air spaces there are less of microbes,
than in the closed rooms.
The constant microflora of air is
shaped at the expense of soil
microorganisms. In its composition
many species of Actinomyces,
Penicillinum, Aspergillus, Mucor and
others go into. There are many
Micrococcous roseus, M. candicans,
M. luteus, Sarcina lutea, S. alba,
S. rosea, Bacillus subtilis, B. mycoides,
B. mesentericus.
Examination of air microflora is made
according to Koch’s sedimentation method or
Krotov’s aspiration method.
A sanitary - hygienic rating of air
includes
general microbial number
sanitary - indicative microorganisms:
Streptococci haеmolyticus,
S. viridans,
Staphylococcus aureus.
The large value there is a cleanness
of air in operation rooms, reanimation
department, dressing rooms, maternity
halls and chambers for neonatal.
Total number of microbes in
operation hall before the operation
should not exceed 500 in 1 м3, and
after operation - 1000 in 1 м3. The
quantity of haemolytic and viridans
streptococci should not be at all.
The
organism of
the man is
occupied
• more than
500 species
of bacteria,
• about 50
species of
viruses,
• more than
20 species of
protozoa.
It is a huge zoological garden.
Normal microflora of the human body:
Constant (obligate, resident, indigenous,
autochthonous) microflora is native, no
imported one of different biotopes.
Transient (temporary, facultative,
allochthonous) microflora is not
aboriginal, it is acquired one.
Normal flora of skin:
Staphylococcus epidermidis
 Staphylococcus aureus
 varius streptococci
 Corynebacterium
 Pseudomonas aeruginosa
 Propionibacterium
 Yeasts
Microflora of an eye
The tears perniciously affect on microbes. In
47 % of people the microflora here is
completely absent.
Only few species have adapted to existence
on a conjunctiva:
 Corynebacterium
 Neisseria
 Staphylococcus
 Mycoplasma
 Adenovirus
 Herpervirus
Normal flora
of the respiratory tract:
 Staphylococcus aureus
 Staphylococcus epidermidis
 Corynebacterium
 varius Streptococci
 Neisseria species
 Haemophilus influenzae
Moraxella lacunata
In a larynx, the trachea and large
bronchuses there are few of microbes.
Smaller bronchi and alveoli are normally
sterile.
Normal flora
of the genitourinary tract
In an outside part of a urethra
 Peptococcus
 Corynebacterium
 Mycobacterium smaegme
 Fusobacterium
 Staphylococcus
 Mycoplasma
are found.
The kidney, the ureter, the bladder and
upper urethra are sterile.
Normal flora of vagina:
Lactobacillus
Corynebacterium
 B. fragilis, varius streptococci
 C. albicans
Internal
reprodactive
normally sterile.
organs
are
Degrees of vaginal secret cleanness
of health woman
I
Epitelhial cells
acid-tolerant
lactobacilli
(Doderllein`s bacilli)
many glicogen
II
the pH is maintained
between 4.4 and 4.6
Degrees of vaginal secret cleanness
of sick women
Epitelhial cells
III
 acid-tolerant lactobacilli
(Doderllein`s bacilli) are
absent
little glicogen
IV
the pH is maintained
between 6.9 and 7.6
many proteins, leucosytes
 staphylococci and
streptococci
Microflora
of the intestinal tract
At birth a gastrointestinal path and feces of the
child are sterile. In 3 - 4 days there is an intensive
invading them by bacteria of genus Escherichia,
Proteus, Veilonella, Lactobacterium, Enterococcus,
Staphylococcus. However, by the end of the first week
putrefacient bacteria are superseded by a lactate
microflora. It mainly Bifidobacterium bifidum, B.
longum, B. infantis, Lactobacillus acidophilus are.
They are a main microflora of the child at nursing. At
artificial feeding or at transition to the mixed feeding
there is an increase of the putrifactive
microorganisms. Bifidobacterium and Lactobacterium
play the large role in decomposition of mammary
milk, help the process of digestion.
Microflora of an oral cavity
In an oral cavity there is a plenty of
microorga-nisms. More than 100 species of
aerobic and anaerobic bacteria are described.
In 1 ml of a spit can be found about 100
million of microbial cells.
Constant (stationary) temperature (37 ºС),
humidity, the oddments of food, alkaline
reaction of a spit and wide aeration promote
reproduction of microbes.
In the oral cavity bacteria are found
on the tooth surface (above all in
subgingival plaque); in the saliva; on
the tongue surface; in the tonsillar
crypts.
The main mass of microbes (70 %) is
in a debris. In 1 mg of dry mass of scurf
can be about 250 million of bacteria.
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Streptococci
Lactobacterium
Veilonella
Neisseria
Corynebacterium
Bacteroides
H. Influenzae
Treponema
Leptospira
C. albicans
Actinimycetes
Mycoplasma
Protozoa.
Microflora of the stomach
Yeast
Sarcina
Fungi
Lactobacterium
Staphylococcus
Campylobacter
Helicobacter pylori
(all up to 30 species).
Microflora
of the small intestine
 Bifidobacterium
 Lactobacillus
Bifidobacterium bifidum
 Enterococcus
 E. coli
Lactobacillus
Normal flora of the colon:
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Bacteria:
Bacteroides
Bifidobacterium
Eubacterium
Fusobacterium
Lactobacillus
coliforms
(Escherichia coli,
Enterobacter)
fecal Streptococci
Clostridium
Fungi:
Candida
Protozoa:
Entamoeba coli,
Trichomonas
hominis
The microflora of a large intestine is
most abundant and is diverse. Here there
are most favourable conditions for
reproduction of many microorganisms.
Now microbiologists have detected and
have described more than 270 species of
bacteria.
Their
common
biomass
compounds about 1,5 kg. During day the
man with feces discharges of 17-18
billions microbes.
Peridontal disease:
A – normal gingiva;
B - disease
Acute necrotizing
ulcerative gingivitis
Importence of normal flora:
1. Colonization resistance
2. Antagonistic role
3. Stimulate immunity
4. Take part in all kinds of metabolism
5. Produce vitamines, enzymes, hormons
6. Digestive role
The dysbacteriosis is change of a
quantitative relation and composition of a
normal microflora of an organism, mainly
of it intestine.
Thus there is a decrease or disappearance
of some bacteria and sharp increase others,
especially infrequent or not characteristic
for the given biotope of microorganisms. As
a rule, the quantity of an facultativeanaerobic microflora is enlarged. It can be
the Gram-negative rods, staphylococci,
Candida albicans and species Clostridium.
Candidiasis
To treat dysbacterioses of an
intestine and colitises we apply special
bacteritic preparatrions: colibacterin,
bifidobacterin, lactobacterin, bificol,
bactisubtil. They contain the dried up
clouds of alive bacteria having strong
antagonistic properties. These eubiotics
reduce a normal microflora of an
intestine.
The gnotobiotes allow more
precisely to study a role of a normal
microflora in synthesis of vitamins and
amino acids, in creation inherent and
artificial immunity. The large value has
gnotobiology in learning space,
conditions of life of the man and
animals in space, in conditions of
durable flight of missiles on other
planets.
Raising gnotobiotic animal
The animals without microbes
(gnotobiotes/germ-free animals) are
divided into some groups:
1. Monobiotes - completely
deprived of microbes;
2. Dibiotes - animals infected by
one species of bacteria;
3. Polybiotes – having two and
more microbial species in organism.