Mycobacterial culture systems

stogdell at earthlink.net stogdell at earthlink.net
Sun Jun 30 23:12:00 EST 1996


>   dgaunt at uhl.uiowa.edu (Dennis Gaunt) writes:
>  Has anyone had experience with the latest culture methods, say
>  from Organon-Technika(sp?), the 9000 system, etc?  If so, what 
>  are your thoughts on cost, proficiency compared with the 460,
>  solid agar, etc.  Thanks for any comments.
>  -- 
>  ----------------------------------------------------------------------
>  | Dennis D. Gaunt                   | Internet: dgaunt at uhl.uiowa.edu | 
>  | The University of Iowa            |    Voice: (319) 335-4500       |
>  | Oakdale Research Campus           |      FAX: (319) 335-4555       |
>  | Iowa City, Iowa  52242            |                                |
>  ----------------------------------------------------------------------
>  
>>>>
We started using the Organon Teknika MB/Bact in January of this year.   Our traditional mycobacterial culture (which we still use) is 
a Lowenstein-Jenson slant and a Middlebrook thin-pour plate.  So far we have been very happy with the MB/Bact.   It is nice to 
know that the instrument is in the "back room" keeping a watchful eye on all the cultures.  Each month one person in our 
microbiology lab is given the task to deal with the mycobacteria cultures.  Due to staffing that person may not get to the AFB cultures 
until the end of the week.  We have noticed that having the MB/Bact reading cultures all of the time reduces the stress levels of 
techs who are not able to look at the solid media till the end of the week. We also feel that it is no longer neccessary to spend as 
many man-hours as we were examining the thin-pour plates under the scope.  We were wasting a lot of time with that and it was a 
very unexciting job.  We have found that at about the same time the MB/Bact flags a bottle positive with acid-fast organisms----- 
there are detectable colonies on the Middlebrook thin-pour plates.  We can then use those colony morphologies on the thin-pour 
plates to help determine which DNA probes to run. This saves a lot of expensive probe reagent were we to blindly run 4 probes on 
each new pos bottle with AFB.   We have had success using fluid from the MB/Bact bottles to run DNA probes; however we have 
found that readings are higher with the probes when colonies themselves are used.  We do have some problems with bacterial and 
fungal contaminations of bottles; but nothing serious.  We had one patient whose solid medias were entirely overgrown with 
aspergillus and usless.  The MB/Bact bottle came through for us and grew   M. avium-complex which we would have never found 
on the solid media.  We are an 800 bed hospital in central Illinois.  Our population has a low incidence of TB and we have not found 
one yet with the MB/Bact.  We usually only get a couple pos TBs a year.  So far since Jan we have found 8 cultures with M. avium 
complex.  We have not had any cultures which were positive on solid media and negative in the MB/Bact.  We have had one 
culture positive in MB/Bact and the solid media was overgrown with aspergillus.  We had one specimen positive in MB/Bact and 
never positive on original solid media.  So out of the 8 positive cultures since Jan. we would have missed 2 of them with our regular 
culture method of LJ slant and Middlebrook thin-pour plate.  We have been happy so far with the instrument but it almost seems to 
be too good to be true.  It finds positives and doesn't give us any trouble.  Being a paranoid group we keep waiting for the disaster to 
happen.  We have been very curious about other labs and their experience with this instrument.  However we have not had any 
contact with anyone.  I recently posted here and got little response.  As for cost I cannot give you any information but I could ask my 
supervisor.  If you would like to e-mail me specific questions I can always pass them on to her.  I do know that several years ago our 
lab tried the 460.  It was not liked and we stopped using it after several months.  It seemed that we had a very high rate of 
contamination of the bottles with bacteria and fungus.  At that time it ws decied the 460 was not worth all of the trouble it caused.  
However, many people use the system so maybe the problem was something unique to us.
				Gail Stogdell    MT(ASCP)
				stogdell at earthlink.net		
				St. John's Hospital
				Springfield,  IL




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