Denitrification by cystic fibrosis pathogens - Stenotrophomonas maltophilia is dormant in sputum

All four pathogens were able to grow anaerobically by NO3− reduction. Denitrification as demonstrated by N2O production was, however, not found in S. maltophilia isolates. The ability to perform denitrification may contribute to the pathogenicity of the infectious isolates since complete denitrification promotes faster anaerobic growth. The inability of S. maltophilia to proliferate by denitrification and therefore grow in the anaerobic CF sputum may explain its low pathogenicity in CF patients.