Media Culture

COMPARISON OF CULTURING MEDIA USE IN TUBERCULOSIS SCREENING

 Tuberculosis

common and often deadly disease, mainly caused by Mycobacterium tuberculosis.  Diagnosis started with screening test  AFB direct smear and culturing method is the standard way of screening TB.  Most common media(egg-based) used in Malaysia  Lowenstein-Jensen media(used before)  OGAWA(now replacing LJ media)

 OGAWA

culture media is better than Lowenstein-Jensen media in terms of cost, growth rate and contamination rate.

 OGAWA

is suitable to be used in highburden lab

Even we have variety of diagnosing method for TB, culturing method is needed as it is cheap even if it took a bit longer time for the mycobacterium to growth. AFB direct smear cannot detect the presence of the bacilli if the amount of the bacteria are still low. Culturing method allowing us to look the growth of the bacteria even if it is still in a small quantity.

 As

we cannot have two type of media used for culturing at the same time, data for Ogawa media is taken from middle of April until early of July 2008 which comprises of 279 positive smear sample and 234 negative smear sample.  For LJ media, data is taken during the time this media was used before being replaced with Ogawa media. Number of sample is as same as number of sample culture on Ogawa. Data taken from year 2000.

Basic ingredient:  Mineral salt solution  Malachite green dye  Homogenized eggs For mineral salt solution and malachite green dye, it has its own constituent to form that solution. Glycerol is the basic ingredient for Ogawa while in LJ, it is the constituent of mineral salt solution

Ingredient Mineral salt solution

OGAWA

LJ

KH2PO4

KH2PO4

Sodium glutamate

MgSO4.7H2O

Distilled H20

Glycerol Magnesium citrate

Malachite green dye Glycerol

Malachite green dye Malachite Asparaginegreen dye sterile distilled Distilled H O H 20 Used sterile distilled H20

2

Already contain inside the minerals solution



By looking at the constituent of Ogawa and LJ, there is a different where Ogawa only contain sodium glutamate while LJ contain MgSO4.7H2O, glycerol, magnesium citrate and asparagine



Other than that differences, they both contain distilled water and Potassium dehydrogen phosphate anhydrous



Found here that, LJ need a lot of ingredient compared to Ogawa. This is why we need more cost on LJ media 

 Growth

rate is high for LJ compared to Ogawa for negative smear sample  Growth rate is higher on Ogawa compared to LJ which is up to 3.3% of difference.  For the contamination rate after inoculation using negative smear sample, there is only slightly different between them.  There is 3.6% difference of contamination rate where Ogawa showing 6.3% contamination while LJ showing 10% contamination.

 Higher

contamination rate in LJ may due to the digestion and decontamination process.  Growth is higher in Ogawa because of the content of higher concentration of glycerol in the ingredient.  Ogawa are cheaper than LJ as it contain less ingredient compared to LJ.  The culturing and smear itself cannot really diagnosing the M.tuberculosis.  To determine this mycobacterium, we need a combination test and also need to look at the medical history of the patient including the x-ray on chest.

 Objective

achieved as there are comparable evidence that support the objectives.  Hypothesis accepted.  Ogawa media is better than LJ in terms of cost, growth rate and contamination rate.