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Normal Flora

• Microbiota

• Normal microbiota=Normal microflora

• Microbiome

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• Resident flora

• Transient flora

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NORMAL FLORA OF THE HUMAN BODY

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Tissue tropism

Essential growth factor

Specific ligands for attachment

to specific receptors located at the

colonization site

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Advantage

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Disadvantage

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Normal flora of the skin

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Normal flora of the Eyes

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EAR

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Normal flora of the Respiratory tract

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Normal flora of the nose

• Corynebacteria

• Staphylococci (S epidermidis, S aureus)

• Streptococci

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Upper respiratory tract • Peptostreptococcus

• Anaerobic cocci

• Veilnollella

• Actillomyces

• Fusobacterium spp

• Streptococcus

• Haemophilus

• Neisseria spp.

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LOWER RESPI RATORY TRACT • Generally sterile

• Transient colonizationvirulent bacteria present in the mouth

• S. pneumoniae

• S. aureus.

• Enterobacteriaceae such as Klebsiella) cause acute disease of

the lower airway.

• Anaerobic cocci

• Anaerobic gram-negative rods

• Fungi such as Candidaalbicans

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Normal flora of the Gastrointestinal tract

Esophagus

Stomach

Proximal small intestine

Distal part of the small intestine

Large intestine (colon)

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Normal flora of the Oral cavity

• Nutrients

• Epithelial cells

• Secretions

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Throat or pharynx

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Esophagus

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Stomach

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Intestinal

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1- Protective functions competing for nutrients and receptors

or directly through the production of antimicrobial

factors, such as bacteriocins and lactic acid

2- Mucosal immune system. IgA

3- Metabolic functions, amino acid requirements

short-chain fatty acids

vitamin K, biotin, and folate and enhance ion absorption.

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Normal flora of the urogenital tract

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