Seven cases of lower respiratory tract infection due to Corynebacteriu
m pseudodiphtheriticum are described. Lower respiratory tract infectio
ns with C. pseudodiphtheriticum in immunocompetent patients are usuall
y associated with pre-existing chronic pulmonary disease, and are some
times associated with endotracheal intubation. Antimicrobial susceptib
ility testing of these isolates showed uniform sensitivity to penicill
in and variable results to erythromycin.