Pseudomonas cepacia

Question

I have a child with CF who always had pseudomonas aeruginosa. Last time we were checked at the lab we had cepacia. I repeated the sputum cultures in three different labs. All three reported pseudomonas, but the first one reported again cepacia. What can I do to find out positively what kind of microbe my child carries? I live in the county.

Answer

Dear friend,
You have a child with CF with chronic colonisation of pseudomonas. You recently had a sputum culuture in your town and the results were positive for cepacia.
You repeated the culture in three different labs. The results were positive for pseudomonas, but not for cepacia. You repeated the culture in the first lab, where again cepacia is reported. You are confused about the conflicting results.
The isolation and identification of BCC (cepacia) is based on certain requirements about its growth with proper culture materials. When usind standarised kits there may arise false negative, or false positive results. This problem is attributed to the high viscocity of bronchial secretions of CF patients, which means that a special processing procedure is required, as well as to the slow growth of the related microrganisms, since a prolonged inocculation period is required for their detection (over 48 hours for pseudomonas and over 96 hours for cepacia). For these reasons, the reliability of standarised kits in identifying these pathogenic microogranisms in CF is reduced.
Axylosoxidan and Smaltophilia can be falsely identified as cepacia, and false negative results for cepacia may be reported when one has not used the proper culture materials.
You must contact the CF center, which is rensposible for your child, and let them guide you about finding a lab that supports and has experience in cultures from bronchial secretions of patients with CF.
Yours friendly,
Dr. Stavros Doudounakis

09.09.2018