Chapter 2 – normal flora

MIC341 - Miss Rashidah Hj Iberahim

Chapter 2 – NORMAL FLORA

Miss Rashidah Hj Iberahim


Skin Flora Oral Cavity Flora Intestinal Flora Urogenital Flora

Content


*microorganism in perianal area enter the

urinary tract (UT) causing infection in internal UT

Can prevent infection by: Medical asepsis – personnel and hospital

environment should be clean from pathogens Surgical asepsis – instrument used should be

sterile and including the surgical room What did you implement in daily life?

Harmful


Skin Flora


Anatomy of the Skin


Different area consist of different microflora.

Example armpits vs forehead. Moisture area will support larger populations;

nutrients from oils and sweat Those normal flora might have capability to

produce oils that known as fatty acid providing an acidic condition of particular area

Initiating host defense against infection in the 1st line stage

But, excess of oils production might resulting an odour of unpleasant smell to the body

Oils production


Beside oils, the 2nd line of host defends is the

sweat that are salty However, in opposite situation, there are

bacteria that able to live in salty area such as Staphylococcus sp.

Majority of the skin flora – Gram +ve : Staphylococcus, Micrococcus and Corynebacterium

Hair follicles inhabitants – mite Demodex folliculorum

Sweating


3rd line defends is regarding the keratin-

degrading fungi It helps in rapid and continuous shedding of

skin cells replacing layer by layer Removing of skin cell together with group of

m/org on the skin

Skin shedding


Producing fatty acids that prevent growth of

other m/org Excretion of lysozyme by sweat glands Desquamation of epithelial

Closing the loop


Gram positive org. Staphylococcus sp Micrococcus Coryneform bacteria

Demodex folliculorum (opening glands – eyebrows)

Normal flora


Oral Cavity Flora


Anatomy of the oral cavity


Basically the 1st area expose to m/org – the

m/org more than people on earth Affect the anatomy of mouth – teeth, tongue Contain saliva use to flush down food and

bacteria to the digestive systems below Level of efficacy of bacteria vary interms of

individual capability – physically and chemically

Resulting a tooth decay which are differ between individual

Mouth


Currently, there are 400 species indentified

colonizing human mouth There are a lots more unknown m/org that

need to be discovered Colonization of m/org on cell lining cheek,

tongue, palate and floor of the mouth resulting bad breath

Major effects on tooth appearance

Ecology of m/org


Intestinal Flora


In esophagus – no normal flora – pH of

stomach inhibit the colonization Until the 2/3 of small intestine rarely contain

normal flora – except lactobacili and streptococci (transient microbes)

The last 1/3 small intestine, the movement become slower and leads to increasing of microbes colonization

GI tract


The main flora in 1/3 last small intestine – Gram-negative Facultitative anaerobe such as

enterobacteriaceae (E.coli) obligate anaerobes (Bacteroides and

Clostridium)

1/3 small intestine


Food remain as long as 60 hrs – long period

leads to high microbes colonization and replication

50% of feces = microbes Mostly Bacteroides Eating foods of raw material derived from

small intestine By-product = vit K for clotting of blood

Large intestine


Urogenital Flora


Anatomy of female


Anatomy of male


All parts are sterile except urogenital opening Urine collection should have ‘clean catch’ technique E.coli and Lactobacillus are common flora =

100,000 bact/ml of urine Collection during direct puncture (suprapubic) =

sterile sample Acid pH, high salt and urea concentration leads to

high m/org growth Urine sample should be refrigerated during

transportation if delay – high multiplication if stir in RT

Urogenital


Mycobacterium smegmatis (acid fast staining

bacili) live in external genitalia of female and male

Esp under penis of uncircumsized male – smegma

If included in the sample, might leads to confusion wt the tuberculosis patient which actually having M. tuberculosis

In male, 1/3 of deep are for genital area don’t have normal flora

Cont.


Due to hormonal changes.. Child-bearing – lactobacili numerous in vagina

(eating glycogen) Glycogen in vaginal cell will be fermented

become lactic acid and pH decrease to 4.7 Childhood and after menopause, lactobacili

absent coz no glycogen –replaced by streptococci and staphylococci due to alkaline pH in vagina

In female..


Mycobacterium smegmatis Lactobacillus E.coli Staphylococcus Streptococcus

Normal flora


To be continue..

Sorry..c u tomorrow nite..

Health & Medicine

Chapter 2 – normal flora