Aerosols and contamination

Question

Hello,
My 7 years-old CF son is treated with nebulised RhDNase. He is using a disposable jet nebuliser (PortaNeb). Recently, 3 different bacteria have been found in high quantity in his sputum: Stenotrophomonas maltophilia, Rhizobium radiobacter, and Chryseobacterium indologenes. Fortunately, they have been eradicated, despite their resistance, with an oral treatment with ciprofloxacin and cotrimoxazole. On one hand, our CF Centre, thinking that these bacteria came from the nebuliser, has stopped the RhDNase treatment. From this date our son shows difficulties to expectorate and coughs more. On the other hand, people renting the nebuliser think that a microbial contamination from the nebuliser is impossible because their devices are systematically disinfected between rentals, because the device of my son was new, and because it was disposable. Moreover, I disinfected weekly the compressor with wipes impregnated with detergent product. At last, the hospital microbiologist (another one that the one of the CF centre), who is regularly in charge of the microbial evaluation of my son sputum, thinks that the 3 germs are environmental bacteria, found, like Pseudomonas aeruginosa, into the ground. These bacteria would be found in the more severe patients or in patients colonised with Staphylococcus aureus (my son is colonised since 18 months). She also said to me that Stenotrophomonas maltophilia and Rhizobium radiobacter were emerging bacteria in CF. She thinks that microbial contamination is not linked to the nebuliser, but maybe because of my son's practice to scratch the ground with his fingers (we are living in the country), and to bite one’s nails, even if his hands are regularly washed. I would know who to believe, knowing that the practitioner of the CF centre is not favourable to aerosols.

Answer

Hello,
You’re right, the 3 bacteria found in your son sputum are emerging bacteria in CF and they are environmental. Contamination with these bacteria has various possible origins: ground, air, water, decayed or unsanitary dwellings … Then, nebulisers and their accessories may be the origin of the microbial contamination. Using inhaled drugs proposed in sterile ampoules, using disposable nebulisers, respecting a rigorous hygiene when preparing the drug (i.e. with previous hands washing) and when maintaining the device (i.e. using only once a disposable nebuliser, or, when using a reusable nebuliser, systematically washing and rinsing the device after each nebulisation, and once a day disinfecting it; also, regularly disinfecting the face mask or the oral tip) undoubtedly prevent this risk. If your son has an as large benefit than that you are describing with RhDNase nebulisation, you should discuss anew with your CF centre about the opportunity of this treatment.
I hope to have responded to your questions.
With my best regards,
Prof. Jean-Christophe Dubus

02.02.2011