اول حاجة سوري مرة كتييير اني اتأخرت تأخير شنيع باني احط موضوووعي
لكني اعتذر وبشدة لكن هادا الشي ما حيتكرر وحتشوفوا بنفسكم
Morphology :
GRAM POSITIVE COCCI , it can be in groups like grapes, single and in pairs
They are non motile غير متحركة and non capsulate بدون كبسووول يحيطها
Culture
It's better to identify it by culture not only by gram staining
لكني اعتذر وبشدة لكن هادا الشي ما حيتكرر وحتشوفوا بنفسكم
Morphology :
GRAM POSITIVE COCCI , it can be in groups like grapes, single and in pairs
They are non motile غير متحركة and non capsulate بدون كبسووول يحيطها
Culture
It's better to identify it by culture not only by gram staining
After culturing it will appear as big colonies (1 mm in diameter)
These colonies are golden yellow colour (that why it calls aureus from a latin word aurum )
These colonies are golden yellow colour (that why it calls aureus from a latin word aurum )
It is grow in any media because it has many enzymes that enable it.
As I said before staphylococcus aureus grow well aerobically , in enriched CO2 and grow anaerobically but less well with temp. range for growth is 10-42 C with optimum 35-37 C.
As I said before staphylococcus aureus grow well aerobically , in enriched CO2 and grow anaerobically but less well with temp. range for growth is 10-42 C with optimum 35-37 C.
وهذه بعض انواع الميديا التي تنمو عليها البكتيريا منها :
Blood agar , choclate (heated blood ) agar:
it is produce yellow cream or white colonies with 1 mm diameter after incubation
some strains are beta hemolytic when grown aerobically
it is produce yellow cream or white colonies with 1 mm diameter after incubation
some strains are beta hemolytic when grown aerobically
زي ما قلت أول إنها لها القدرة على تحليل الدم بسبب الهيموليسن اللي تفرزه ولأنه هاذي الميديا مصنوعة من دم الخرفان فرح تبان المستعمرة لونها مصفر نوعا ما وحولها فارغ بسبب أنها حللت الدم اللي حولينها روعة لو تشوفوها في ال بتري
macConkey agar:
Small colonies (0.1-0.5mm) and most strains here are lactose fermenting
Small colonies (0.1-0.5mm) and most strains here are lactose fermenting
Mannitol salt agar:
Selective media for identifying s .Aureus from faecal specimen when investigating Staphylococcal food poisoning
To screen also for nasal carrier
Selective media for identifying s .Aureus from faecal specimen when investigating Staphylococcal food poisoning
To screen also for nasal carrier
There is special biochemical test which help to differentiate S.aureus from other species
Coagulase test:
s. aureus gives positive agglutination in coagulase test
s. aureus gives positive agglutination in coagulase test
it is used for differienting between pathogenic and non-pathogenic strains of Staphylococcus. Bacteria that produce coagulase use it as a defense mechanism by clotting the areas of plasma around them thereby enabling themselves to resist phagocytosis by the host's immune system. The sample in question is usually inoculated onto 0.5 ml of rabbit plasma and incubated at 37 degrees Celsius for one to four hours. A positive test is denoted by a clot formation in the test tube after the allotted time.
DNase test:
this test is use to identify the s .aureus that produce deoxyribonuclease enzyme (DNase).which hydrolyzed (DNA)
The test organisms cultured on a medium which contain DNA.
this test is use to identify the s .aureus that produce deoxyribonuclease enzyme (DNase).which hydrolyzed (DNA)
The test organisms cultured on a medium which contain DNA.
The antibiotic sensitivity test
It is done by using methicillin (which can stand out side the human body)
If the bacteria was sensitive to this antibiotic then it will report MSSA(methicillin sensitive staphylococcus aureus )
If the bacteria was sensitive to this antibiotic then it will report MSSA(methicillin sensitive staphylococcus aureus )
If the bacteria were resistant to the methicllin antibiotic ,then it will report MRSS(methicillin resistant staphylococcus aureus ) and the best treatment is vancomycin which is the only antibiotic that can killed this resistant kind of bacteria
هاذي اهم الأشياء التي تمتاز بها ومن المهم انكم تتذكروووها
وتحياتي لكم ولصبركم واشوووفكم على خير مع مايكرو اورجانسم ثانية
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