CDST_LT: SIRE susceptibility testing

The BACTEC MGIT 960 susceptibility testing for Streptomycin (S), Isoniazid (I), Rifampin (R) and Ethambutol (E), called SIRE, is a rapid and qualitative method that uses critical test concentrations of the four drugs.

 

Components of SIRE Kit

 

The kit has one vial for each of the drugs (S, I, R and E) and 8 vials of the MGIT 960 SIRE Supplement.

 

 Drugs:

 

 

Drug	Approximate lyophilized drug per vial
Streptomycin (S)	332 µg
Isoniazid (I)	33.2 µg
Rifampin (R)	332µg
Ethambutol (E)	1660µg

   

 

SIRE Supplement: It differs from the MGIT Growth Supplement and contains the following:

 

Bovine Albumin	50g/l
Dextrose	20g/l
Catalase	0.03g/l
Oleic Acid	0.6g/l

Resource

 

Mycobacteriology Laboratory Manual         

 

Assessment

 

 

Question​	Answer 1​	Answer 2​	Answer 3​	Answer 4​	Correct answer​	Correct explanation​	Page id​	Part of Pre-test​	Part of Post-te
Which of the following is NOT a component of the SIRE kit?	Streptomycin (S)	Isoniazid (I)	Rifabutin  (R)	Ethambutol (E)	Answer 4	Components of the SIRE Kit are Streptomycin (S), Isoniazid (I), Rifampin (R), and Ethambutol (E).

 

BACTEC MGIT 960 SIRE Kit for critical concentrations contains the following drugs in lyophilized form. Each kit contains one each of S, I, R, and E drug vial and 8 vials of MGIT 960 SIRE Supplement.

 

Drugs

Streptomycin - approximate lyophilized drug per vial --------------- 332µg

INH - approximate drug per vial ---------------------------------------- 33.2 µg

Rifampin – approximate drug per vial ---------------------------------- 332 µg

Ethambutol – approximate drug per vial -------------------------------1660 µg

 

SIRE supplement

The SIRE supplement vial differs from the MGIT Growth Supplement and contains, per litre of purified water, the following:

 

Bovine albumin -------------------- 50.0 g

Dextrose----------------------------- 20.0 g

Catalase ----------------------------- 0.03 g

Oleic acid ---------------------------- 0.6 g

 

 Storage

Upon receipt, refrigerate the lyophilized drugs at 2-8ºC. Reconstitute prior to use. Once opened and reconstituted, the leftover drug solutions may be frozen in aliquots at -20ºC or lower and stored for up to 6 months or up to the date of original expiry, whichever comes sooner. Once thawed, discard the leftover and do not store or refreeze.    

 

Reconstitution of SIRE Drug Lyophilized Drugs (stock preparation)

 

Reconstitute the drugs with the appropriate volume of diluent as described below. Volumes vary with different drugs. Failure to use the appropriate volume will invalidate these tests.

 

Preparation of drugs in MGIT 960 SIRE Kit

 

1 Reconstitute each Streptomycin lyophilized drug vial with 4 ml of sterile distilled/ deionized water to make a stock solution of 83μg/ml.

 

2 Reconstitute each Isoniazid lyophilized drug vial with 4 ml of sterile distilled/ deionized water to make a stock solution of 8.3μg/ml.

 

3 Reconstitute each Rifampicin lyophilized drug vial with 4 ml of sterile distilled/ deionized water to make a stock solution of 83μg/ml.

 

4 Reconstitute each Ethambutol lyophilized drug vial with 4 ml of sterile distilled/ deionized water to make a stock solution of 415μg/ml.

 

 

Resource

 

Mycobacteriology Laboratory Manual       

Assessment

 

Question​	Answer 1​	Answer 2​	Answer 3​	Answer 4​	Correct answer​	Correct explanation​	Page id​	Part of Pre-test​	Part of Post-te
The opened and reconstituted drug solutions can be stored under which conditions?	Stored at -20ºC or lower for up to 6 months	Stored at -20ºC or lower up to the date of the original expiry	Stored at -20ºC or lower for up to 6 months or up to the date of original expiry, whichever comes sooner	Stored at -20ºC or lower for up to 3 months or up to the date of original expiry, whichever comes sooner	3	Once opened and reconstituted, the leftover drug solutions may be frozen in aliquots at -20ºC or lower and stored for up to 6 months or up to the date of original expiry, whichever comes sooner.