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CF patient

CF patient, 19 years old, diagnosed with CF as a baby and has staphyloccus aureus. Diagnosed with pseudomonas a few months ago.
My question is: should the patient take tobramicina, as when he was last tested for bacteria and had sputum taken, he did not have pseudomonas any more. Can pseudomonas disappear or the test was not done properly?
Thank you.
Mira Zdravkovic

Thank you for your question. I take it that this patient frequently cultures S. aureus and had a first isolate of pseudomonas a few months ago.

When pseudomonas is isolated the first time, many different regimens exist in different countries to try to eradicate it. There is some data on some regimens, but the optimal form of therapy is not established. In our center in Belfast we are following this regimen:

For 1st isolate pseudomonas and providing the patient is clinically stable, we would treat with nebulised colistin and oral ciprofloxcin for a period of 3 months. If the patient is unwell we would treat initially with IV antibiotics and follow through with nebulised / oral therapy for 3 months.
If a patient also frequently cultures S. aureus we would also consider using tobramycin in place of colistin depending on drug sensitivities.

During this treatment period we would obtain samples of sputum on a monthly basis. If the sputum samples are clear at the end of the 3 months and the patient is clinically stable, we would stop treatment but would continue to closely monitor the sputum on a two monthly basis.

If the patient is clinically unstable or continues to culture Pseudomonas we would consider a further course of IV antibiotics and continue nebulised treatment and ciprofloxacin for a further 3 months thereafter.

If Pseudomonas persists after IV and nebulised antibiotic treatment, a long term nebulised anti-pseudomonal antibiotic should be given.

That means, if a proper treatment was initiated on your patient and after that several sputum samples were negative, it can be stopped. In case even thoug there was no treatment up to the actual timepoint the last sputum test had been negative for pseudomonas, one should do some more tests in a short timeinterval to confirm the absence of Pseudomonas. It is not impossible that it disappeared without therapy, but it is also very likely that one test might be false negative because of the tested material or technical aspects of the test.
Stuart Elborn
The answer is edited by: Prof Stuart Elborn