I made a terrible mistake! By written RESISTANT instead of SENSITIVE!!!
The OP50 was SENSITIVE not resistant to all antibiotics tested.
I may have a starting Alzheimer ... Sorry.
On 26 Aug 1997, Tritech Research wrote:
>fodoran at FALCO.GEOBIO.ELTE.HU,Internet writes:
> ANTIBIOTICS SENSITIVITY OF OP50.
>> Csaba Bognar(2), Tibor Vellai(1) and Andras Fodor(1),
> 1. Dept. Genetics, Eotvos University, H-1088 Budapest, Muzeum krt. 4/A,
> 2. Bela Johann National Institute of Public Health in Hungary, Department
> of Bacteriology, (OKI), H-1097 Budapest, Gyali ut 2-6, Hungary.
>> E. coli OP50 is used practically by everybody in the C. elegans Community
> as natural food for C.elegans. Our substrain what we use was kindly
> provided by Ian Hope in 1995. We have tested its antibiotics sensitivity,
> by the paper disc method routinly used the OKI. We used 30 ug/ml of each
> antibiotics tested. The filter paper discs are out on the center of the
> NGM plate seeded by OP bacteria. An inhibition zone develops, if the
> antibiotics is effective against the baccteria under test. Conventionally,
> if the diameter oif the inhibition zone is smaller then 2 cm, we conclude
> that the bacteria is resistant to the antibiotics tested. We tested 24
> antibiotics, as follows:
>> gentamycin; tobramycin; sumetrolim; chloramphenicol; tetracycline;
> ampicyllin; karbenicillin; cefalexine; cefamandol; cefuroxime; amykacin;
> netylmycine; azlocilline; mezlocillin; ceftriaxone; cefatoxim;
> cefroperazon; ofloxacin; pestloxacin; cyprofloxacim; ceftazidin; cefaclor;
> augmentin; and kanamycin. (Some of the names are probably written in very
> Hungarian; we promise the correct them in the Newsletter article).
>> Well, we found that OP50 was completely resistant to all these
>> I hope these data help Liz and other fellow Colleauges to work with OP50.
>> Faithfully yours,
>> Andras and his gang.
> This sounds very strange to me (?) If true, it would be one of the heartiest
> (and most dangerous) strains of bacteria in the world (?) My experience
> with OP50 is that it is killed easily by Amp and Str. 2 cm requires a lot
> of diffusion. Might this be too much to ask from the filter disks? Is it
> possible that doing the test on NGM with a high agar or agarose content is
> limiting diffusion? Could this possibly be a contaminating yeast?
> Andy Papp
>tritech_research at LAMG.COM>
Dr. Andras Fodor e-mail: fodoran at ludens.elte.hu
Associate Professor or: fodoran at falco.elte.hu
Eotvos University Phone: +36.1.266.1296
Department of Genetics +36.1.267.5444 ext. 2348
Budapest, Muzeum krt. 4/A FAX: +36.1.266.2694