Topic : BACTEC machine
•BACTEC culture vials
•-Blue top is for aerobic bacteria culture
•-Yellow top is for anaerobic bacteria culture
•-Red top is for fungi culture
•-Sliver top is for blood culture for paedritic
What goes on inside the machine???
1) Presence of microorganisms causes metabolism of nutrients in the culture medium releasing CO2 into the medium
2) The CO2 produced will react with a dye in the vial sensor
3) Light Emitting Diodes (LEDs) modulated by the dye will illuminate the racks, activating the vial’s fluorescent sensors.
4) Instrument’s photo detectors take the readings of the fluorescence which corresponds to the amount of CO2 released by the organisms.
5) Raw data from detector is sent to rack microprocessor
6) Positivity analysis is performed in the microprocessor
7) Positive vial lamp illuminates, audible alarm sounds and positive station displayed on the monitor.
What happen when there is a postive result?
· When positive vials are identified, the lab technologist pulls them out of the incubation for further investigations.
· After the blood culture is flagged positive, a 6-fold dilution is made, with 0.2ml (8 drops) of blood to every 1 ml of saline, then subculture on appropriate plates
· For aerobic culture, we use blood agar plate(BAP) and maconkey agar plate(MAC)
· For anaerobic culture, we use BAP, MAC and anaerobic blood agar plate(ANA)
· The plates are incubated overnight.
· The culture is dispensed onto a glass slide and direct gram staining is done, using crystal violet, Gram’s iodine, acetone and safranin to see presence of gram positive cocci or gram negative bacilli.
Therefore, a positive result means that there is a bacterial or fungal infection in the patient’s bloodstream thus, needs to be treated immediately and a negative result means that there is a probability that a patient is suffering from an infection from other causes. Some microorganisms like viruses are more difficult to grow in culture and more testing may be required.
Okay now roughly i hope u guys understand what i am talking about. If you want to enquire about anything can just call me aites!! I guess this is where I say goodbye!! N i am awaiting for my next adventure this week!!!
Enjoy your SIP people!!!!!
Name: Mohamed Amir
Class: TG02
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14 comments:
Hi Amir..hahah
Anyway, a question for you..how long does the BACTEC machine take to produce the results? coz at my lab, i don't remember seeing a BACTEC machine...my supervisor instead has to incubate the culture bottles in the incubator and check for growth at 24 hrs, 48 hrs and 7th day. thanks! =)
Nur Farhana
0604834B
Hey Amir,
You mentioned about "negative result means that there is a probability that a patient is suffering from an infection from other causes". How do know that its other infection when the result only tell you its neg for that particular test? COuld it be that the patient might not have any infection at all?
Culture medium release CO2 that will react with a dye in the vial sensor,what is a vial sensor?
Name: DYana (0605169B)
Hey Amir
Looks like you love it there at your attachment place. That's great! =)
Anyway, yup, your entry is easy to understand. But I just have 2 questions for you:
1) You mentioned about the BACTEC culture vials, does these vials contains, are they culture medium? (Do they have better viability efficiency than normal culture medium?) You only explained what culture are they for...
2) "Some microorganisms like viruses are more difficult to grow in culture and more testing may be required." (Quoted)
If it's not too much trouble, could you give some examples on what are the more tests to be done?
Hahaz! 2 weeks down and 18 more weeks to go. Do take care at your attachment place =)
Many thanks
Quan Jun
TG02
Group 08
Commented on: 08 July 2008
hi amir
you said "Some microorganisms like viruses are more difficult to grow in culture and more testing may be required."
Can you name some examples of the viruses and tests that may require more testing?
thanks.
Elyana
0606676E
is your lab automated then amir? oh and how does the Co2 react with the dye?
yuxuan
aMiR to Nur Farhana
ooohh for the bactec machine you do need to keep on checking, if you want you can just use the LIS that is connected to the machine to gather information. Both aerobic and anaerobic bottles are kept in the BACTEC machine for at least 5 days. If there is postive the vials are taken out and if there is no growth then it will be reported and the bottles are discarded.
aMiR to DYana
okay yup the result tells me that is negative. This indicate that there are no bacteria growth in the blood hence, the cause of the infection is not due to bacteria. Blood is a huge reservoir for many different types of microorganisms to infect. A wide variety of microorganism types can be isolated from blood. So thats why there is a probability that other types of microorganisms like fungi or viruses that are involved in the infection. Blood borne infections may lead to many complications if not cure immediately. It can infect the whole body,leading to disseminated infections. If all the specific tests for the presence of the different microorganism show negative result then we can conclude that the patient has no infections.
Ans to 2nd quest:
Vial sensor?? At the base of each vial there is a sensor which responds to the concentration of CO2 produced by the metabolism of microorganisms or the consumption of oxygen needed
for the growth of microorgnisms. The sensor is monitored by the machine every ten
minutes for an increase in its fluorescence.I post a picture of how the machine works. you can read at my new post.
aMiR to QJ
Hi QJ!!.. hope you are doing fine
For 1st quest:
For each aerobic vial, it contains:
• 25 mL Enriched Soybean-Casein Digest broth (TSB)
• 0.05% Sodium Polyanetholesulfonate (SPS)
• Cationic and Non-ionic Absorbing Resins
• Carbon dioxide (CO2)
• Oxygen (O2)
• Sensor for the detection of fluorescence
For each anaerboic vial, it contains:
25 mL pre-reduced enriched Soybean-Casein Digest broth.
• 0.05% SPS
• Resins
• CO2 and Nitrogen gas (N2)
• Sensor for the detection of fluorescence.
* Resins have been incorporated into BACTEC culture media to enhance recovery of organisms without a need for special processing.
For 2nd quest: I read this from the internet. http://www.labtestsonline.org/understanding/analytes/blood_culture/test.html
I am not so sure as i am in bacteriology, there are no virus tests. But i will find out for you and let you know.
aMiR to Elyana
hey!! I read that from source at the internet: http://www.labtestsonline.org/understanding/analytes/blood_culture/test.html
I am not so sure as i am in bacteriology, there are no virus tests. But i will find out for you and let you know the tests. But what i mean was that for viruses it is difficult to use a blood culture design to see for the presence of viruses. So other tests use to culture viruses.
hi
Can you roughly share with us how you perform blood culture?
Justina
0605950E
TG01
Hello AMIR!
MICROBIOLOGY ROCKS, but you're not suppose to right where you are attached to. haha
Anyway, normally patient will have their blood sample taken into the blue and yellow bottle (aerobic and anaerobic culture) right and some maybe the one for fungal culture. So why the paediatric only have 1 bottle which is the silver cap bottle? Does it only have anaerobic or aerobic cultures and why?
LESLIE (:
eh bro! I came upon ur post, and I wanna ask erm..the test u mentioned, it detects the presence of bacteria, but it wouldn tells you the specific type of bacteria is it?
Hope its not a dumb qn. Thanks!
Lloyd
Hi Amir,
Cool SIP experience!!! Hmmm...I have some questions for you.
1)Other than blood culture, what other type of microbiology culture do you perform?
2)How much patient's blood sample is inserted into the vials?
3)What is rack microprocessor?
4)What are some examples of gram positive cocci or gram negative bacilli bacteria you detect?
5)How many blood culture do you normally perform a day and the duration for each culture?
6)"Therefore, a positive result means that there is a bacterial or fungal infection in the patient’s bloodstream thus, needs to be treated immediately "
What are those bacterial or fungal infection? Why is there an urge for patients to be treated immediately?
7)"a negative result means that there is a probability that a patient is suffering from an infection from other causes."
-Why can't a negative result mean the paitent can be diagnosed with no infection?
-Why does the probability exist?
-Are there any test to confirm this probability?
-What are those other causes?
8)What agar/culuture medium do viruses grow in? Why are they more difficult to grow? Can it be possibly due their fastidious nature?
Thankz =)
Han Yang
TG01
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