Hello.

It's not a simple question... I'll try to answer.

Carbapenemases Resistant Enterobacteriaceae can survive on plastic and other materials in the hospitali if not properly sterilized. The best way to select them, is to use a selective media (there is one we use called "CRE") that allows only CRE organisms to survive. Anyway, even Pseudomonas spp which are carbapenemases resistant will develop on this agar, you can discriminate them by the color of the colonies.

If you don't have the chance to use a selective specific media, you could try to use MHBroth or Brain Heart broth, and inoculate the antibiotic (Meropenem, Imipenem, Ertapenem) into it and then dissolve an ambiental swab, suitably collected from the enviroment you are interested in, in the solution. If there is a torbidity after an overnight incubation, the organism you selected is a Carbapenemases resistant. Then you can sow the torbidity to have an ID of the bacteria/bacterias you selected.

Other way: you could use a McConkey agar plate where you sow the samples and put an antibiotic disk on it, if it produce an halo after 24h incubation at 37°C, it's not carbapenem resistant.

Anyway, you should know that Etrapenem doesent work very well, cause Pseudomonas is naturally resistant to it, but it's quite ok with Klebsiella and E.coli.

What sample to collect? Swabs from equipments, withdrawals from liquid solution and, if you got the chance, contact agar plates (the selective media here would be perfect) from smooth surfaces.

What are you exacly interested in?

Thanks a lot for your answer...

Yup selective media can be used to detect them CRE or pseudomonas... I am actually thinking and wondering what is the best way to collect them from the environment.. Should I use a dry dacron swab.. Or a wet one.. or there is/are special instruments that one can use to collect them and then put them on the media aforementioned by you...

Use wet swabs, far better!  Is simple, cheap and faster!

Swabs and agar selective plates always work.

Good luck!

Environmental sampling done using wet cotton swabs/ dacron swabs are useful for sampling, you could then inoculate them onto Mac Conkey agar containing 1 micro gram of imipenem or BHI broth containg a disk of imipenem.