Isolation of a Non-Toxigenic Corynebacterium diphtheriae Strain in a Patient with Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Corynebacterium diphtheriae is a nonsporulating, nonencapsulated, nonmotile, pleomorphic, Gram-positive bacillus that displays a characteristic morphology resembling “Chinese characters” on Gram stain examination. It is the etiologic agent of diphtheria, an upper respiratory tract disease with high morbidity and mortality rates, especially among children. Once considered a major worldwide health problem, today diphtheria is almost a forgotten disease because of the high rates of worldwide immunization practices using the toxoid vaccine. Vaccination has reduced the number of cases to nearly anecdotal levels in Western countries (1). However, nontoxigenic C. diphtheriae strains have become increasingly recognized as an emerging pathogen, causing severe invasive disease worldwide (2-5).