تويت
سلاااااااام لجميع المشاركين في مختبرات العرب.
اشكركم جدا على جميع المواضيع القيمة المطروحة في المنتدى. وارجو منكم طرح مواضيع حول الجودة النوعية وخصوصا في قسم الميكرو لاب ومن لدية فورمات حول quality control لا يبخل علينا .
Method of sensitivity
[Once the organism is identified from the clinical specimen, antibiotic sensitivity is put by mixing 3 to 5 isolated colonies from the pure culture of the growth with the Tryptic soy Broth [5ML] or nutrient broth or sterile normal saline. The turbidity is then matched against turbidity standard which is prepared in the laboratory by adding 0.05 ml of barium chloride solution to 99.5ml of the sulphuric acid & then mixed. When matched with the standard, the inoculum should give semi confluent growth. The turbidity of the standard is equivalent to an overnight broth culture.An alternate method for determining if the broth culture has achieved the turbidity of the McFarland No. 0.5 standard is to use a spectrophotometer. Place the tube in the spectrophotometer and read the absorbance at 600nm; the absorbance of the McFarland No. 0.5 standard is approximately 0.132.Using a sterile loop about 4mm diameter, apply a loopful of test organism suspension or subculture to the centre of the sensitivity testing plate.Use a sterile dry cotton wool swab to spread the inoculum evenly across the centre third of the plate. The upper & lower thirds of the plate should be inoculated with control strains. Allow the innoculum to dry for a few minutes & then put antibiotic sensitivity discs under sterile conditions. Incubate the plates aerobically at 370C for 24 hours. However for methicillin disc, the plates should be incubated at 350C. After overnight incubation look for the inhibition zone & measure its radius from the edge of the disc to the edge of the zone. The end point of the inhibition is where growth starts. Report the sensitivity of the organism after measuring the diameter of inhibition zone & compare with the Zone Diameter Interpretive chart which shows the criteria of the organism for being either sensitive or resistant to a particular antibiotic depending upon the measurement of inhibition zone
اشكركم جدا على جميع المواضيع القيمة المطروحة في المنتدى. وارجو منكم طرح مواضيع حول الجودة النوعية وخصوصا في قسم الميكرو لاب ومن لدية فورمات حول quality control لا يبخل علينا .
Method of sensitivity
[Once the organism is identified from the clinical specimen, antibiotic sensitivity is put by mixing 3 to 5 isolated colonies from the pure culture of the growth with the Tryptic soy Broth [5ML] or nutrient broth or sterile normal saline. The turbidity is then matched against turbidity standard which is prepared in the laboratory by adding 0.05 ml of barium chloride solution to 99.5ml of the sulphuric acid & then mixed. When matched with the standard, the inoculum should give semi confluent growth. The turbidity of the standard is equivalent to an overnight broth culture.An alternate method for determining if the broth culture has achieved the turbidity of the McFarland No. 0.5 standard is to use a spectrophotometer. Place the tube in the spectrophotometer and read the absorbance at 600nm; the absorbance of the McFarland No. 0.5 standard is approximately 0.132.Using a sterile loop about 4mm diameter, apply a loopful of test organism suspension or subculture to the centre of the sensitivity testing plate.Use a sterile dry cotton wool swab to spread the inoculum evenly across the centre third of the plate. The upper & lower thirds of the plate should be inoculated with control strains. Allow the innoculum to dry for a few minutes & then put antibiotic sensitivity discs under sterile conditions. Incubate the plates aerobically at 370C for 24 hours. However for methicillin disc, the plates should be incubated at 350C. After overnight incubation look for the inhibition zone & measure its radius from the edge of the disc to the edge of the zone. The end point of the inhibition is where growth starts. Report the sensitivity of the organism after measuring the diameter of inhibition zone & compare with the Zone Diameter Interpretive chart which shows the criteria of the organism for being either sensitive or resistant to a particular antibiotic depending upon the measurement of inhibition zone