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Corynebacterium amycolatum: An Unexpected Pathogen in the Ear
Mallika Sengupta1, P Naina2, V Balaji3
1Post-graduate Registrar, Department of Clinical Microbiology, Christian Medical College , Vellore, India .
Journal of Clinical and Diagnostic Research : JCDR
|January 28, 2016
Summary
Corynebacterium amycolatum, a common bacteria, is increasingly linked to infections. This study identifies it as a rare cause of ear infections, often resistant to common antibiotics like ceftriaxone and imipenem.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Otolaryngology
Background:
- Non-diphtheritic Corynebacteria are emerging pathogens.
- Corynebacterium amycolatum is frequently isolated from various infection sites.
- The role of C. amycolatum in ear infections is largely undocumented.
Purpose of the Study:
- To report the occurrence and characteristics of ear infections caused by Corynebacterium amycolatum.
- To highlight the diagnostic challenges and antibiotic resistance patterns of C. amycolatum in otitis cases.
- To emphasize the need for accurate identification and susceptibility testing for effective management.
Main Methods:
- Retrospective analysis of 12 cases of ear infection attributed to C. amycolatum.
- Microscopic examination (Gram stain, Albert's stain) and culture on blood agar.
- Antibiotic susceptibility testing (AST) for common antimicrobials.
- Polymerase Chain Reaction (PCR) for toxA and toxB genes.
- Genomic sequencing for isolate confirmation.
Main Results:
- C. amycolatum was identified as the causative agent in 12 cases of pyogenic ear infections.
- Isolates exhibited resistance to ceftriaxone (8/12) and imipenem (4/12).
- All isolates were susceptible to vancomycin, and negative for toxA/toxB genes.
- Genomic sequencing confirmed the species identity.
Conclusions:
- Corynebacterium amycolatum is an uncommon but significant cause of ear infections.
- The organism displays notable antibiotic resistance, particularly to ceftriaxone and imipenem.
- Accurate identification and AST are crucial for appropriate treatment of C. amycolatum-associated otitis.
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