Corynebacterium pseudodiphtheriticum causing severe pneumonia in secondary immunoglobulin deficiency

Corynebacterium pseudodiphtheriticum causing severe pneumonia in secondary immunoglobulin deficiency Background: Corynebacterium pseudodiphtheriticum is of increasing importance because of the rising number of immunocompromised patients. Pneumonia, but also endocarditis, urinary tract infections or keratitis can be caused by this bacteria in case of immunosuppression. Taking corynebacterium pseudodiphtheriticum into consideration as causitive agent provides for a fast onset of targeted antibiotic therapy. History and findings: A 69-year-old man with immunoglobulin deficiency due to a chronic lymphocytic leukemia presented with typical clinical, laboratory and imaging evidence of pneumonia. Diagnosis, treatment and course: Corynebacterium pseudodiphtheriticum was detected as causative agent. After a prolongated course targeted antibiotic therapy and immunoglobulin substitution resulted in full recovery of the patient. Conclusion: In immunocompromised patients Corynebacterium pseudodiphtheriticum should be taken into consideration as causative bacterium of pneumonia. Especially, immunoglobuline deficiency seems to be associated with pneumonia caused by Corynebacterium pseudodiphtheriticum. Therefore, immunoglobulin substitution as well as a targeted antibiotic therapy should be considered.