Persistent Pseudomonas aeruginosa

Question

Dear expert team,
Pseudomonas aeruginosa has been found in the samples of our daughter (6. yrs) for the first time in january this year. Inhalation with colistin followed for 4 weeks together with Ciprofloxacin orally. A new throat swab after 4 weeks had been free of PA. Shotly after this, another throat swab was done, the PA has again been found. According to our center, our daughter inhaled now 2 times daily a mixture of Colistin and Tobramycin and took Levofloxacin. After 4 weeks, only the inhalaton of Colistin was continued and the next swab was PA free. Again some time later the next swab was done, this had again PA. Then she inhaled again Colistin and Tobi together and took again Levofloxacin. After the 4 weeks we only contiunded Colistin. The next swab was good again and the one after that had again PA. This continues until today and now we have again an actual finding of PA. The only thing that changed is that the number of germs reduced from massive to moderate. Now we are quite hopeless that the PA will go away ever again. Now the center want to add a third inhalative antibiotic drug before in the end an i.v. therapy is done. One gets the information from other centers that the i.v. therapy is initiated if the first trial of 4 weeks to eliminate PA was not successful. Our center is of the opionion, that the inhalative therapy against the PA is more effective and says that there would be no guarantee, that the PA disappears after 14 days of i.v. We are quite insecure and do not know what to do. It would be nice to get another opinion. Many thanks

Answer

Hello,
even if we cannot review a very long time span, a chronic infection with PA is emerging in your child. According to the guidelines about PA diagnostics we have a chronic PA infection, if more than 50% of microbiological samples within one year showed the PA germ.
Here it seems to be like this, that as soon as the inhalative antibiotic treatment is finished, PA can be found again. It does not matter, if the number of germs is high or low. The qualititave finding is most important.
It will be written in the guidelines recently, that after a non-successful inhalative antibiotic treatment plus e.g. the oral intake of ciprofloxacin an i.v. antibiotic treatment with e.g. ceftazidim (150mg/kg/d in 2 dosages) and tobramycin (8-10mg/kg/d in one dosage) should be initiated. After this, an inhalative antibiotic treatment should be done in the on/off modus over 4 weeks with 300mg Tobramycin two times a day or Colistin 1 Mio units 2 times a day. Also a sequential inhalative antibiotic treatment can be considered, therefore 4 weeks e.g. with Tobramycin followed by 4 weeks of Colistin or Aztreonam. A combined inhalative therapy - like here with Colistin and Tobramycin - has been proven in pilot studies.
There are good hints in the literature for the eradication of a PA infection with the sole inhalative treatment, even only with 2 times daily of 80mg Tobramycin.
In this very persistent case, an i.v. antibiotic treatment would for sure be advantageous, followed by a consequent inhalative treatment until PA cannot be found in the samples for more than one year. Then the PA germ should not be found over a longer period of time in 4 microbiological samples without anti-PA antibiotic therapy. Only then, one could stop the anti-PA antibiotic treatment under frequent controls.
Indeed there is no guarantee, that after an i.v. treatment the PA germ can be eradicated for a longer period of time. However, there are enough proves that the i.v. antibiotic treatment is an evidence based method of eradication.
It is important to know, if there are clinical symptoms with increased cough and increased secretions. In case of undoubtfull signs of a bronchitis, I would always prefer an i.v. antibiotic treatment.
The treating physician of your daughter knows the situation the best, therefore it is very important to discuss the prodecures with him.
Best regards,
Dr. H.-E. Heuer

12.09.2015