pseudomonas treatment

Question

Dear ECORN Experts, I have a 5 years daughter. Here where I live we do not have a cf specialist so we go to another country for controls. She was diagnosed with cf at 1 one month. Her sputum test came back positive for PA (Pseudomonas aeruginosa) for the first time on January this year. We started therapy oral ciprofloxacin 4 weeks and inhaled colistin untill she had three negative sputum tests. Since the results were negative we stopped inhaling colistin, but in July the sputum test was again positive. We did oral cipro for 6 weeks and again started inhaling colistin. Then in September it was again positive and now she will be on oral cipro for 3 months and continue inhaling colistin. Our dr told us that she has to be on inhaled colistine for all her life. I was reading another treatments and I see that sometimes the I.v. therapy is recommended.
Do you think that we should maybe try I.V. therapy before deciding to put her on lifelong colistin, because we are buying it and it is becoming very hard for us?
thank you in advance

Answer

Dear Questioner
Many thanks for submitting your question to us.

Eradication therapy, as you have described, is given when there is a “new” or “first” isolation. The aim of eradication therapy is to remove pseudomonas aeruginosa from the lungs completely. When speaking about infection with pseudomonas aeruginosa there are many definitions of what is a “new” or “first” isolation of P. aeruginosa. They all agree that it is a positive result in a person who’s tests have previously been negative. We also have to think about how often testing has been carried out (i.e. every 3 months is more likely to detect P. aeruginosa early versus every 6 months) and the method of obtaining the sample (i.e. sputum spontaneously produced is more likely to detect P. aeruginosa early than throat swabs). With regards to the best treatment to eradicate P. aeruginosa, this is still an active area of research. There are many trials published that compare different treatments for eradication. Mostly they combine an inhaled antibiotic (for example nebulised tobramycin or colistin) with an oral antibiotic (e.g. ciprofloxacin). Some trials have also explored intravenous antibiotics. Use of intravenous antibiotics would have to be determined by the team looking after your daughter. Over all, trials have suggested that eradication success rates of between 60 and 80% can be achieved but have not so far indicated that one method is better than another. In other words, out of all patients treated, between 60 and 80% will be negative for P. aeruginosa by the end of treatment.

From your description it appears that the clinical team treating your child may be considering that the infection with Pseudomonas aeruginosa will become chronic. Once this happens it is unlikely that pseudomonas aeruginosa will be eradicated from the lungs and therapy moves towards “dampening” or “reducing” the infection, rather than removing it completely. Chronic therapy usually includes inhaled therapy such as nebulised colistin or tobramycin. Some centres alternate colistin with tobramycin month by month.

There is a paper by Döring et al (1) dealing with the treatment of Pseudomonas aeruginosa. For those patients with persistent or recurrent Pseudomonas detection, the first line therapy should be repeated, if this also fails, other so-called second or third line therapies should be tried, e.g. another inhalative drug such as Tobramycin or a systemic treatment with intravenous antibiotics may be tried.

You should discuss your concerns with the CF team who is looking after your child. They should be able to advise you of all the options for treatment and ways to cover the cost of this treatment.

Best wishes, Lisa and Damian
(Belfast)

(1) Döring et al in the Journal of Cystic Fibrosis 11 (2012) 461-479: “Treatment of lung infection in patients with cystic fibrosis: Current and future strategies”

26.11.2013