normal body flora ppt
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4th October 2010
In Today’s Class Define normal flora/biota
Identify sterile and non-sterile sites
Describe the normal flora/biota at non-sterile sites.
Benefits and harm of normal body flora
Definitions Normal Body Flora
Normal Microflora
Normal Microbiota
Describes the various microbial species which inhabit the skin, mucous membranes and other non-sterile sites on the animal without causing disease.
Mixture of organisms regularly found at an anatomical site
Definitions Resident microflora
those organisms that are always present on the body.
Transient microflora
those present temporarily and under certain conditions.
Types of Relationships Commensalism
Mutualism
Parasitism
Sites of Normal BiotaSite Normal Flora Sterile
Liver √
Skin √
Mucous membranes
√
Lungs √
Colon √
Blood √
Middle and inner ear
√
Brain √
CSF √
Sites of Normal BiotaSite Normal Flora Sterile
Bones √
Vagina √
Heart √
Amniotic fluid √
Distal urethra √
Urinary bladder √
Muscle √
External ear √
Factors influencing the composition of normal flora Genetics
Age
Stress
Geographic location
Climate
Nutrition
Diet
Drug therapy
Hormonal changes
Components of normal body flora Mainly bacteria
Eukaryotic fungi
Protists
Methanogenic Archaea
Normal body flora and tissues Show tissue tropism
Specialized ligands or adhesins
Capsules
Fibriae
Cell wall components
Construct biofilms
Sites of normal flora: The skin Bacteria Staphylococcus spp. Staphylococcous epidermidis
Staphylococcous aureus
Propionibacterium acnes
Micrococcus sp.
Yeasts Pityrosporum
Mites Demodex spp.
Sites of normal flora: The conjunctivae Staphylococcus sp.
Staphylococcus epidermidis
Staphylococcus aureus
Propionibacterium acnes
Streptococcus spp.
Haemophilus sp.
Sites of normal flora: Upper respiratory tract of humans Staphylococcus spp.
Staphylococcus epidermidis
Staphylococcus aureus
Corynebacterium spp.
Streptococcus spp.
Streptococcus pneumonaie
Streptococcus pyogenes
Haemophilus influenza
Neisseria meningitides
Sites of normal body flora: Oral cavity Streptococcus spp.
Streptococcus salivarius (until teeth appear)
Streptococcus mutans
Streptococcus sanguis
Staphylococcus spp.
Bacteroides spp.
Diphtheroids (nonpathogenic Corynebacterium spp.)
Lactobacillus spp.
Normal body flora: Upper intestinal tract Upper intestinal tract is usually inhospitable to normal
flora
However
Some Lactobacillus spp.
Half of the American population Helicobacter pylori(pathogenic)
Normal body flora: Lower intestinal tract- small intestine Lactobacillus spp.
Enterococcus spp.
Enterococcus faecalis
Escherichia coli
Bacteriodes spp.
Normal body flora: Large intestine Bacteria present here are qualitatively similar to that
found in faeces
Bacteriodes spp.
Lactobacillus spp.
Bifidobacterium spp.
Clostridium spp.
Clostridium perfringens
Clostridium septicum
Normal body flora: Large intestine (cont’d) Enterobacteriaceae
E. coli
Klebsiella
Enterobacter
Pseudomonas aeruginosa
Proteus mirabilis
Methanogens
Normal body flora: Urogenital tract Sterile
Urinary tract flushes every few hours
Normal body flora: Urethra Staphylococcus spp.
Staphylococcus epidermidis
Staphylococcus aureus
Streptococcus spp.
Enterococcus faecalis
E. coli
Proteus sp.
Corynebacterium sp.
Normal body flora: vagina Corynebacterium spp.
Staphylococcus spp.
Streptococcus spp.
Lactobacillus spp.
E. coli
Yeasts: Candida albicans
Milk Micrococci
Staphylococci
Streptococci
Mycoplasmas
Corynebacterium bovis
Rumen: Ruminants such as cattle, sheep, goats Rumen bacteria classified according to function
Fibre-digesting or Cellulolytic bacteria
Ruminococcus flavefacians
Ruminococcus albus
Bacteriodes succinogenes
Butyrivibrio fibrisolvens (one of the most numerous and versatile bacteria present).
Rumen: cattle, sheep, goats Rumen bacteria classified according to function
Starch and Sugar-Digesting (or Amylolytic) bacteria
Bacteriodes ruminocola
Bacteriodes amylophilus
Selenomonas ruminantium
Streptococcus bovis
Succinomonas amylolytica
Benefits of normal body flora The synthesis and excretion of vitamins
The prevention of colonization by other pathogens
Normal flora can antagonize other bacteria
Normal flora can stimulate the development of certain tissues
The stimulation of the production of natural antibodies
Harmful effects of normal flora Bacterial synergism
Competition for nutrients
Induction of low grade toxaemia
Normal flora may be agents of disease
Transfer to susceptible host
Bacterial Synergism
That is one organism can help the other one grow and survive. Examples of this occur when normal flora supply vitamins and other growth factors for pathogenic bacteria to grow, this is called cross-feeding. Another example of synergism occurs between microbes such as in “staph-protected infections” when a penicillin-resistant staphylococcus (a component of normal flora) shares its drug resistance with other pathogens.
Thank You for your Attention
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