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Send your questions to editor@cfww.org and we’ll find answers!

I have two daughters with CF. Someone recently referred me to your newsletter updated in January 2005 (Edition 5). A. Christopher Boyd’s “New Approaches to Therapy,” was one of the best-written and most comprehensive pieces I have read in quite some time.

As a parent of CF patients, the complexity of this disease and related science has added to our frustrations and anxiety. We have gradually educated ourselves to understand a little more about what's going on with our daughters. Please pass along my appreciation to the author and others involved in publishing this update. Thank you.

--Scott Williams, North Carolina, USA

Q: We want to grow Burkholderia cepacia to saturation in nutrient broth at room temperature (22 ºC). Will E. coli / Salmonella be able to grow and compete with B. cepacia? (I suspect the answer is yes but I would like to confirm it from an expert). How can one eliminate E. coli / Salmonella contaminants?

--Henriette van Heerden, South Africa

A: At room temperature Burkholderia cepacia grows slower than most common contaminants, so E. coli and Salmonella would quickly outgrow B. cepacia if they were present. You can add inhibitors to the nutrient broth. What inhibitors used will depend on the type of contamination that may be expected. If trying to isolate B. cepacia from soil different inhibitors would be used than if trying to isolate B. cepacia from respiratory samples. The following inhibitors are used in a commonly used respiratory growth medium; a combination of 10 mg/L gentamicin, 600,000 U/L polymixin B sulfate and 2.5 mg/L vancomycin. E. coli and Salmonella would most likely be inhibited by just the gentamicin if they were the only other organisms present.

-- Deborah Henry, Research Technologist, Department of Paediatrics, Division of Infectious and Immunological Diseases, University of British Columbia, Canada

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