A colleague from another hospital called me to ask about 4 month old infant in their PICU with bilateral pneumonia and shock. A urine test was positive for Legionella. A culture and PCR of sputum were just taken. The boy had diarrhea before it all started. It is not nosocomial infection and his immune status is normal. He has leukopenia and high LDH but with normal LFT. He received azithromycin orally for 2 days and his condition is getting worse. I advised him to give IV azithromycin, and because of his severe condition, to add levofloxacin to the treatment (not sure if it is better than monotherapy). He will also take some tests for immune deficiency and we are waiting for final tests for the Legionella. I will be happy to hear your opinion about the treatment, and, of course, about the case. I feel that we should have a registry for pediatric Legionella.
Don’t worry about using non-evidenced based approaches, just follow your instinct as to what is right and document it. After a while, the evidence will come and you will be the one who provided it. You can use rifampin for 2 – 3 days. Rifampin will interact with many other drugs but it is the most potent agent against Legionella in vitro and in vivo. 2 – 3 days may be pivotal during this critical stage, and a short duration may be enough. In the meantime, culture the drinking water of this infant! Use DGVP media to eradicate commensal water flora and save the Legionella that you isolate.