Corynebacterium amycolatum peritonitis in a patient undergoing peritoneal dialysis: case report and literature review.

Peritoneal dialysis is a blood purification technique used in cases of end-stage chronic kidney failure, based on the filtering capabilities of the peritoneum. Infections, often caused by poor asepsis during catheter manipulation, are generally attributed to Staphylococcus epidermidis and Staphylococcus aureus. Corynebacterium, usually considered non-pathogenic, is rarely involved in these infections. We present a case of peritonitis due to Corynebacterium amycolatum in a patient undergoing peritoneal dialysis. The diagnosis was made based on cytobacteriological examination of the dialysate fluid, which on two occasions showed high levels of white blood cells with a predominance of neutrophilic polymorphonuclear and a monomorphic appearance of colonies on agar medium, whose identification by biochemical tests and antibiotic sensitivity study confirmed the presence of C. amycolatum. The patient was successfully treated with vancomycin, resulting in symptom resolution and sterilization of the dialysate fluid. Although rare, the involvement of Corynebacterium species underscores the importance of confirming its pathogenicity. Further studies are needed to better understand the epidemiology of these infections and guide future treatments. This case also highlights the need for a rigorous approach to confirming the pathogenicity of Corynebacterium despite its traditional classification as a contaminant.