Sequential infections of Campylobacter jejuni and Salmonella gastroenteritis complicated by myocarditis: a case report

Background: Myocarditis is a rare but serious complication of bacterial gastroenteritis, occurring when intestinal infections extend to systemic inflammation involving the myocardium. Although viral etiologies are most prominent in the literature, increasing evidence implicates that certain bacterial pathogens, usually regarded as confined to the gastrointestinal tract, provoke cardiac inflammation through mechanisms that are poorly understood. Case presentation: We report a case of recurrent myocarditis in a 34-year-old previously healthy male, with each episode temporally associated with a distinct episode of enteric infection – initially due to Campylobacter jejuni and subsequently Salmonella enterica . The latter presentation was characterized by constitutional symptoms, biochemical evidence of myocardial injury, and confirmatory imaging findings, necessitating a high index of suspicion to establish the diagnosis. The patient responded well to a combination of targeted antimicrobial therapy and anti-inflammatory pharmacologic intervention. Conclusion: The presence of this pattern involving two different bacterial pathogens raises significant questions regarding host susceptibility, immune system activation, and overall immunopathogenesis of bacterial myocarditis. It highlights the need to broaden the differential diagnosis in patients with gastrointestinal illness who present with systemic or cardiac-related clinical manifestations. As this phenomenon is likely underrecognized, particularly in the absence of classic cardiac symptoms, timely identification and multidisciplinary management are crucial for optimizing outcomes and reducing the risk of long-term myocardial complications. By presenting this rare and illustrative case, we aim to contribute to the evolving recognition of bacterial myocarditis as a distinct clinical entity and to prompt further inquiry into the host-pathogen dynamics that may underlie its pathophysiology.