Microbiology Lecture - 06 Microflora

Normal microflora of a human’s body micro ecology

Normal microflora - is the composition of symbiotic microorganisms formed during evolution, inhabiting skin and mucous membranes of a human body, stayed in the dynamic stable balance

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Qualitative and quantitative compound of

Normal microflora depends on: -State of Health -Age -Type of a diet -Climate conditions -Ecological conditions

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Normal microflora may be arranged into the groups: 1. Skin microflora 2. Microflora of conjunctiva 3. Microflora of a mouth and upper respiratory tract 4. Microflora of gastrointestinal tract and rectum 5. Microflora of urine genital tract 4

Symbiotic microorganisms inhabiting the same area of a body form one ecosystem. All microorganisms of one ecosystem may be arranged into 2 groups:

Indigenous or resident microflora

Transient microflora

nonpathogenic or potentially relatively fixed types pathogenic microorganisms of microorganisms that inhabit some area regularly found in a given area for a short period at a given age 5

Mother’s intestinal and vaginal microflora of medicine personal

of the environment

microflora

microflora

Microflora of the newborn baby

3 sources of newborns microbiota 6

The role of Normal Microflora Colonization resistance - protection from diseases:  NM inhibits pathogens by production of lactic and acetic acids and bacteriocins occupies cell receptors of mucous membranes metabolizes nutrient substrates activates immune system

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The role of Normal Microflora Assimilation of nutrients oligosaccharides - by Bifidobacterium Polysaccharides - by Bacteroides Regulation of Gas balance in the intestine Acid balance in the intestine produce vitamins K, B; amino acids 8

Skin microflora The predominant m/o of the humans skin are aerobic and anaerobic gram positive cocci and rods. Staphylococcus aureus

Limitation factors of skin microflora: pH of skin Secreting of fatty acids Secreting of lysozyme Presence of oxygen 9

Actinomyces

Propionibacterium

Gram positive rods can be detected in normal microflora of skin 10

Normal microflora of Skin Resident m/o • Gram positive cocci: Micrococcus Staphylococcus • Gram positive rods: Corynebacterium Propionibacterium Brevibacterium

Transient m/o • Gram positive cocci: Sarcina • Gram positive rods: Bacillus Actinomyces • Yeasts: Candida • Fungi

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Microflora of a mouth and upper respiratory tract

Veilonella spp

Haemophillus influenzae

Bacteroides fragilis

Neisseria meningitidis

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Normal microflora of nasopharingx and oral cavity Resident •

Gram positive cocci: Streptococcus Micrococcus Staphylococcus • Gram negative cocci: Neisseria Veilonella • Gram positive rods: Corynebacterium Lactobacterium • Gram negative rods: Bacteroides

Transient • •

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Gram positive cocci: Peptococcus Gram positive rods: Actinomyces Bacillus Gram negative rods: Fusobacterium Yeasts: Candida

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Normal microflora of urine genital tract

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Different species of Lactobacillus are predominant

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Vagina Resident m/o Gram positive cocci: Streptococcus Staphylococcus Gram negative cocci: Veilonella Gram positive rods: Lactobacillus Gram negative rods: 14 Prevotella

Normal microflora of urine genital tract

Streptococcus group B

Vagina Transient m/o • Gram positive cocci: Peptococcus Streptococci group B • Gram positive rods: Bifidobacterium Coryneforming bacteria • Gram negative rods: Fusobacterium • Yeasts: 15 Candida

Normal microflora of urine genital tract Urethra Resident m/o • Gram positive cocci: Streptococcus Staphylococcus Peptococcus Peptostreptococcus • Gram negative cocci: Veilonella

Transient m/o • Gram negative rods: Prevotella E. coli • Yeasts: Candida

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Microflora of Gastrointestinal tract (GIT) The most heavily colonized area. All microorganisms of GIT are arranged into ecosystems: Stomach and duodenum per gramm Jejunum and ileum

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10³

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104-107

Colon and rectum

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107-1012

bacteria

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Intestinal Microflora of a newborn (1 month of life) Breast-fed child The predominant resident m/o are different Bifidobacterium species (about 90%) and Lactobacillus, Bacteroides, Streptococci group D, E. coli transient m/o: Klebsiella, Staphylococcus, Clostridium

Bottle-fed child Bifidobacterium and Lactobacillus assosiated with Bacteroides, Clostridium, Streptococci group D , E. coli transient m/o: Enterobacter,Klebsiella Proteus, Citrobacter, Staphylococcus,Bacillus, Candida 18

Intestinal Microflora of adults Resident m/o • Gram positive rods: Bifidobacterium Lactobacillus Propionibacterium • Gram positive cocci: Streptococci group D (=Enterococci)

Bifidobacterium longum

Gram negative cocci: Veilonella • Gram negative rods: Bacteroides,Fusobacterium 19 E. coli

Intestinal Microflora of adults Transient m/o

Clostridium

• Gram positive cocci: Peptococcus • Gram positive rods: Clostridium Bacillus • Gram negative rods: Enterobacteriaceae • Yeasts: Candida 20

Dysbiosis is qualitative and quantitative alterations of normal microflora, induced by violation of ecological balance between microbial populations Dysbiosis isn’t a disease, it appears as a symptom after: 1.Infection process or somatic disease 2. Prolonged therapy with antibiotics, hormones etc. 3. Radiation or immunosuppressive therapy 4. Total changing of diet, climate 5. Prolonged stress 6. Prolonged staying in the exclusive space (cosmonauts, sailors in submarines) 7. Radiation sickness 21

Dysbiosis Compensatory stage:

Sub Insignificant compensatory decreasing of stage: one group of resident m/o.

decreasing of several residents and increasing of transients.

Decompensatory stage: elimination of several groups of residents, translocation of some transients into the other ecosystems. May appier local infection 22

Biopreparations to correct Dysbiosis • Probiotics – contain pure culture of a resident m/o (living) • Prebiotics – contain nutrient substrate (growth factor) which can be fermentated by resident m/o • Synbiotics - contain mixed nutrient substrate and pure culture of a resident m/o

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Diagnosis of Dysbiosis • Cultural (Bacteriologic) method - qualitative and quantitative examination

• Molecular-genetics methods: Polymerase Chain reactions (PCR, RT-PCR)

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Polymerase Chain reaction

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Result s of PC R wi ll b e vi si ba le in g el elec trop horesi s

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• Ampliphycator for PCR 27

Gnotobiology Is the science which studies mechanisms of microbial influence to host immune system on a model of germ-free animals • Germ-free animals have no their own microflora – sterile animals • Germ-free animals live in sterile conditions • Germ-free animals eat sterile food

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