Lecture04normalflore-phage

8/2/2019 Lecture04normalflore-phage

1/32

Lecture 4

Symbiotic relations and microbes

Normal microflore

Parasitic relations among microorganisms

Bacteriophages


2/32

Symbiosis represents an intimate mutually relation oforganisms of different species. They develop together better

than separately. Sometimes the adaptation of two organismsbecomes so great, that they lose their ability to existseparately (symbiosis of the fungus and blue-green algae,nitrogen-fixing bacteria.


3/32

Symbiotic relationship


4/32

Ants cultivate fungi in pure culture

The fungi degrade cellulose that the animals cannot/

Anaerobic bacteria within the rumen

degrade polyccharides

Symbiosis of microorganisms and animals


5/32

NORMAL HUMAN MICROFLORA

Normal microflora, or microbiota species that are

generally found within the stable mixture of microbialcommunity associated with particular body tissueis the result of a adaptation of microorganism to

certain parts of the body

1.normal and constant microfloraResident floraMicrobes which can be repeatedly cultured from a

given site over time

2.temporary (casual) microflora.Transient floraMicrobes which may initially inhabit a site after

exposure, but do not persistColonization Establishment of a microbial population in the animal host


6/32


7/32

Skin flora

Coagulase-negative Staphylococci

S. epidermidis(opportunistic infections)

Skin "diphtheroids" Corynebacteriumspecies (opportunistic)

Propionibacterium acnes(acne)


8/32

BODY SITERESIDENT MICROBIOTA Factors influencing microbial community

composition

SKIN most abundant are non-pathogenic

Staphylococcus, Sarcina; also occur

Micrococcus, diphtheroids etc.; some

fungi and Gram-negative bacteria

except in moist regions ( 80mln 1.2

bill.)

Low water activity and fatty acids production

limit numbers and types of

microorganisms on the skin

Anaerobes Aerobes Anaerobes AerobesPatient 1 Patient 2


9/32

ORAL CAVITYSuitable pH weakly alkaline

and tC favourable medium,

food substances, action of

lysozyme

Gram smear of Throat Swab


10/32

Oral flora

Streptococcusspecies (Gram positive cocci in chains)

"Viridans" streptococci (endocarditis) S. mutans(dental caries)

S. sanguis

S. salivrius

S. mitis

S. sobrinus

S. milleri group(brain, liver abscesses, bacteremia)

Actinomyces(Gram positive branching bacilli) A. viscosus(dental caries)

A. israelii(cervicofacial abscesses)

Anaerobic Gram negative bacilli (gingivitis, lung abscess) Porphyromonas gingivalis

Prevotella melaninogenicus

Fusobacteria

Treponema denticola(spirochaete) (gingivitis)

160 species:


11/32

Dental cariesMajor etiological agent

Streptococcus mutans

Diseaseloss of tooth enamel, dentinabscess formation, loss of tooth

Pathogenesis

Formation of dental plaque (biofilm),calculus (deposition of salts)

Bacterial biofilm, numerous speciesProduction of extracellular

polysaccharide polymers

Fermentation of sucrose, production oforganic acids

Demineralization of enamel, dentinhttp://www.dent.umich.edu/research/loeschelabs/


12/32

Skin Cultures from Forearm

Aerobic

Aerobic

Anaerobic

Anaerobic

Subject 1

Subject 2

Normal Bacterial Flora of the Skin Is Predominantly Anaerobic

Upper respiratory tract (nasal cavity

and nasopharynx)mostly Streptococci(St.pyogenes, St. pneumoniae); also occur

Neisseria,Haemophilus,Bacteroids,

Staphylococci

Lower respiratory tractnone

alveoli and bronchi are usually sterile Phagocytic

cells prevent colonization

Ability to resist nonspecific

defensessalivas

bactericidal features

(lysozymes), mucus

adsorption, phagocytosis by

leucocytes

Factors influencing microbial

community composition


13/32

Vaginal tractLactobacilli

(Doderlein rods),Fusobacterium,Staphylococci, Streptococci,

Bacteroids, yeast etc.

Large surface area and

secretions of nutrients; acidityand bactericidal secrets limits

species within population

Factors influencing microbial


Upper urinary tract (kidneys and bladder) -none

Filtration and outward fluidflow prevent the establishmentof microbiota

BODY SITERESIDENT MICROBIOTA


14/32

Gram smear of Vaginal SwabNormal vaginal Gram stain


15/32

Bacterial Vaginosis

Pathogenesis: abnormal vaginal flora

association with absence of H2O2producingLactobacillusspecies (L. crispatus) elevated vaginal pH predominance of Gardnerella vaginalis

Gram variable coccobacilli (Gram positive structure)

overgrowth of anaerobic bacteria

Prevotella, Porphyromonas, Bacteroides, Atobobiumvaginae, others

production of amines (trimethylamine) inducestransudation and exfoliation of epithelial cells

degradation of mucins producing thin homogenousdischarge

Gram-negative anaerobic bacilli increased production of cervical cytokines (IL1, IL8, TNF)


16/32

Bacterial Vaginosis

Diagnosis

observation of "clue cell" on microscopic examination of

vaginal smear ( Gram stain), adherent grayish discharge,

production of volatile malodorous amines on addition of KOH

vaginal pH > 4.5

"clue cell


17/32

STOMACH - mostlyLactobacteria, also occur

Campylobacteria, Fungi, Sarcina

and others.May be - Helicobacter pylori

Acidic pH, digestive enzymeslimit the number of species

pH-2,5 100 cells \mlpH-4,510000 cells\ml

SMALL INTESTINE

Lactobacteria, Enterococci, E.

coli, Bifidobacteria etc. few

species

Gall, mucus secretions,

secretory IgA

BODY SITERESIDENT MICROBIOTA Factors influencing microbial



18/32

Helicobacter pylori in Gastric Biopsy


19/32

LARGE INTESTINE (bowel)around

200 spp:

Iobligate non-spore-forminganaerobes (Bifidobacteria and

Bacteroids) 9699 %;

IIfacultative anaerobes (E. coli,

Lactobacilli,Enterococci);

III

very few Staphylococci,Proteus,

Candida, Clostridium,Pseudomonas;

Abundance of substrates (pH,

temp., humidity) for growth of

resident microbiota;

About one-third of the dry weight of the faeces of is made up of

microbes. Daily, an adult human excretes about 17 million

billion micro-organisms with the excrements.


20/32

Gram smear of Fecal SwabGram smear of Fecal Swab


21/32

Representatives Quantity(in norm)in

1 g

The eubiotic( probiotic)

preparations

Bifidobacteria 109-1011(85-95%)

Bifidobacterin

Bificol

Lactobacilli 107-109 Lactobacterin

Enterobacteria 107-109 Colibacterin

Bacteroides

(nonspore forming

anaerobes)

109-1010

Cocci 105-106 Bioflorin( Italy)

Clostridium 103-104

Baccillus 103-104 Bactisubtil

LARGE INTESTINE

THE ROLE OF NORMAL MICROBIOTA


22/32

THE ROLE OF NORMAL MICROBIOTA

Factor of nonspecific defense of the body againstinfections with pathogens

a.) colonizatory resistance,

b.) production of allelopathic substances(bacteriocins, fatty acids, lactic acid etc.)

c.) synthesis of nutrients essential to the host(vitamins B1, B2, B6, B12, K etc.)

d.) participation in metabolism of somecompounds (cholesterol, gall acids, vitamins)

e.) stimulation of immune system by microbial

antigens


23/32


24/32

Bdellovibrio

Parasitism (parasitos sponger)


25/32

BACTERIOPHAGES

viruses whose host is a bacterial cell

CLASSIFICATION OF PHAGESOrigin

E. Coli, C. Diphteria, V. Cholera, etc.Genome

single-stranded

double-strandedDNARNA

Gr.1 DNA containing, lyze bacteriawith F- plazmids

Gr.2 small RNA containing

Gr.3 - odd (3,7 ) T-phageswith short tail

Gr.4 odd (1,5 ) -phagetail is contractil

Gr.5 even (2,4,6 ) DNA containing,tail is contractil

F.DErrel -1916 year


26/32

Morphology

Cubic(isometric) - all kind of

genome

Filamentous (helical) -single-stranded DNA

Complex -long or shortcontractile tail

double-stranded DNA


27/32

Specificity (host cell range)

Polyvalent replicate within host

cell of several species

Monophages replicate withinspecific host cell species

Typing phages replicate onlywithin specific host cell strain


28/32

STAGES OF PHAGE REPLICATION

Specific adsorptionPenetration and uncoating

Establishment of phage genomePhage proteins and NA synthesis

AssemblyRelease

Type of interaction with bacterial host

1.Lytic phage (virulent)

2.Temperate phage (lysogenic)


29/32


30/32

Andr Michel Lwoff

1902-1994

Nobel prize 1965 y.


31/32

APPLICATION OF PHAGESTherapy

ProphylacticTyping,

diagnostic

Gene engineering

DIAGNOSTICIdentification of certain bacteriophage in sampleIdentification of microorganism species in sample

Phage typing identification of strain and source of the pathogen.


32/32

Lecture04normalflore-phage

Documents

Transcript of Lecture04normalflore-phage