Mike: Hello, I'm Mike Clarke, podcast editor for the Cochrane Library. People with cystic fibrosis are particularly susceptible to chest infection. It's important to find treatments for these infections and a Cochrane Review from Cochrane Cystic Fibrosis examines the evidence for the use of antibiotics. Nikki Rowbotham, respiratory paediatrician, who is based in the East Midland in the UK and one of the authors of the June 2023 update of the review, tells us more in this podcast.

Nikki: Cystic fibrosis, or CF, is an inherited condition which affects around 70,000 people worldwide. It causes difficulties in clearing mucus from the airways, which leads to recurrent chest infections. These can become chronic, which frequently happens with a common germ called Pseudomonas aeruginosa. By their twenties, most people with CF will have chronic Pseudomonas infection in their lungs, causing frequent admissions to hospital, worsening cough and other symptoms, including a deterioration in quality of life and a shorter life.
When the infection appears for the first time, it can be eradicated with antibiotics but, once it has gained a foothold, Pseudomonas is impossible to get rid of. For this reason, clinical teams check for Pseudomonas every time they see a patient with CF and, if they find the infection, they give antibiotics to eradicate it. However, although this is effective in the short term, Pseudomonas infection often recurs and chronic infection usually occurs eventually.
Our Cochrane Review aimed to see whether antibiotic strategies can eradicate Pseudomonas and prevent chronic infection. We wanted to see if any type of antibiotic therapy is better than another, and to look at any unwanted side effects. We considered trials in which intravenous, oral or inhaled antibiotics had been compared to placebo or no treatment, as well as head-to-head studies comparing one antibiotic combination with another.
We found 11 eligible studies, with a total of approximately 1500 participants. Four were new studies for this update and we now have twice as many participants as in the 2017 version of the review.
Four of the trials compared active treatment with placebo or no treatment. Combining the results of the three that compared inhaled tobramycin to placebo showed effective eradication at one and two months after the start of treatment. The fourth trial tested inhaled colistin combined with oral ciprofloxacin and found that this reduced chronic Pseudomonas infection two years after eradication treatment.
The 2020 TORPEDO trial explored the route of antibiotic administration. It compared intravenous antibiotics alongside inhaled antibiotics versus oral antibiotics alongside inhaled antibiotics. There was no difference in eradication rates between 3 and 15 months, meaning that it is just as effective to treat this infection with oral antibiotics.
Other trials compared different treatment durations or different antibiotic combinations. None showed that any particular treatment is clearly better or worse than any other but, equally, no trial was large enough to say that one approach is as good as any other. One trial compared 28 days of colistin given together with ciprofloxacin, a combination widely used in Europe, against the same duration of tobramycin given together with ciprofloxacin, which is preferred in the USA. Both regimens showed similar rates of eradication, but during the trial the number of people with another germ causing lung infection in CF, Stenotrophomonas maltophilia, increased in both groups.
In summary, we know that chronic Pseudomonas infection reduces the quality and the length of life of people with CF. Eradication therapy using nebulised antibiotics, either alone or in combination with oral antibiotics, is better than no treatment for early infection with Pseudomonas and eradication may be sustained for up to two years.
However, there is still not enough evidence to say which antibiotic strategy should be used for early eradiation and whether any strategies decrease mortality or morbidity, improve quality of life, or are linked to side effects compared to placebo or standard treatment. We found no differences in rates of eradication of Pseudomonas between active treatments, but we did find evidence that intravenous antibiotic treatment is not better than oral antibiotics. Oral antibiotic eradication regimens may lead to reduced treatment burden and reduce the potential harms that come with intravenous administration, and lead to significant savings in healthcare costs.

Mike: You can find more detail about the trials in Nikki's review, including the specific treatments that were compared in the head-to-head trials by going online to Cochrane library dot com and searching for the review with the words "Pseudomonas and cystic fibrosis".