BACKGROUND: Cardiac implantable electronic device (CIED) infections are usually caused by gram-positive bacteria, whereas gram-negative pathogens are uncommon.

CASE REPORT: We report a case of pacemaker pocket infection caused by Campylobacter jejuni in an immunocompromised patient. The patient underwent uncomplicated dual-chamber pacemaker implantation for sick sinus syndrome. At the first scheduled follow-up, after receiving a diagnosis of primary central nervous system diffuse large B-cell lymphoma and beginning chemotherapy with corticosteroids, swelling and subcutaneous fluid accumulation over the device pocket were observed. There were no local inflammatory signs; the patient had no systemic symptoms or recent history of diarrhea, abdominal pain, nausea, vomiting, or other gastrointestinal symptoms. Inflammatory markers were mildly elevated. Device pocket aspiration yielded straw-colored serous fluid; cultures of pocket fluid and blood grew C. jejuni, prompting a change from empirical amoxicillin-clavulanate to targeted macrolide therapy (intravenous clarithromycin) based on antimicrobial susceptibility testing. Transesophageal echocardiography showed no vegetations on the leads. The entire pacing system (generator and leads) was extracted, and temporary pacing was provided. Inflammatory markers became normalized during continued antibiotic therapy. After clinical stabilization, a new dual-chamber pacemaker was implanted contralaterally. The patient was discharged without signs of persistent infection and remains under regular outpatient follow-up.

CONCLUSIONS: This case emphasizes that subtle pocket changes in immunocompromised patients may indicate CIED infection, even in the absence of systemic symptoms. The absence of gastrointestinal symptoms suggests silent Campylobacter bacteremia with secondary seeding of the device pocket. Early microbiological sampling, pathogen-directed antimicrobial therapy, and complete device removal remain essential for cure.

Keywords: Pacemaker, Artificial, infections, Device Removal, Device Lead Extraction