versa trek instrument

Done by: NAIF D. AL-HARBI

Group 2 0856278

Versa TREK instrument

Content: -Introduction

-Principle -Specimens

-Reagents - Detection of mycobacteria

-Advantages -Disadvantage


Introduction: The Versa TREK instrument for the isolation of mycobacteria from clinical specimens consists of a modular arrangement of incubator and detection instrument and medium-containing culture bottle.The Versa TREK instrument consist of a series of drawers , each containing location for placement of culture bottles. The Myco bottles contain 7H9 broth and cellulose sponge utilized as a growth platform. The Myco bottles are supplemented with Myco growth supplement (middlebrook oleic acid-albumin-dextrose-catalase ) and an antimicrobial agent solution prior to inoculation with the specimen. The sponges provide a growth support matrix and increase surface area exposed to headspace oxygen


Each location contains a sensor to which the inoculated culture bottle is attached via a plastic connector. Versa TREK instrument encompasses the monitoring of rate pressure changes over time associated with O2 consumption and or production of all gases (CO2 , H2 , N2).


Principle: The Versa TREK instrument detect mycobacterial growth by automatically monitoring (every 24 min) the rate of O2 consumption within the headspace of culture bottle. This information is used to generate a curve for each bottle. Internal algorithms analyze these changes and signal a positive culture when appropriate. The Versa TREK sensor is located in instrument not the in the bottle.


Specimens: Almost all specimen types , including sputum , urine , blood and bone marrow specimens , can be utilized in the Versa TREK system. Decontamination of specimens obtained from body sites normally contaminated with bacterial flora prior to inoculation into Myco culture bottles. Viscous specimen like sputa must also be digested prior to inoculation.


Reagents: 1 -Myco broth : Middlebrook 7H9

with casitone/glycerol and cellulose Sponges . The bottle fill with 11.5 ml.

2-Myco GS : ( growth supplement )Oleic acid , albumin , dextrose , and catalase , the bottle fill with 25 ml .


3 -Antibiotic inhibitor or supplement: -Polymyxin B -Vancomycin

-Nalidixic acid -Amphotericin B

4 -Versa TREK (ESP) bottle connectors.


Detection of mycobacteria: 1 )clinical specimens

2)Decontamination/Digestion ( for non-sterile specimens ) By add 3% NaOH + NALC + equal volume from sample (15 min) , then add buffer

phosphate , then centrifuge 15 min ( 3000 RPM ) , then keep sediment.

3 )Mycobacterial culture bottle

Add : 1) growth supplement (1 ml)

2 )antibiotic supplement or PNVA (0.5 ml)

3 )specimen inoculation (up to 1 ml) , then incubation ( up to 42 days ).

4 )Versa TREK Mycobacterial growth algorithm

5 )Detection

By 1 )AFB

2 )Biochemical testing 3 )DNA probe testing


Advantages : 1 )Fully automated and continuous monitoring

system . 2 )Detect the positive sample within 7 days ( short

time ) . 3 )Use graph analysis .

4 )Using a small volume of patient sample and reagents .

5 )Can perform mycobacterium tuberculosis susceptibility testing ( kit include ; rifampin , isoniazid , ethambutol ).


Disadvantages : 1 )High cost.

2 )If there is alarm for positive sample the system can’t differentiate between true positive and

contamination . 3 )If negative sample the result available in 6 weeks

.


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versa trek instrument

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