Insights into Arcanobacterium haemolyticum: A Narrative Review of an Emerging Pathogen Revisited

Arcanobacterium haemolyticum is a facultative anaerobic, Gram-positive bacillus that has garnered attention due to its role in human infections, particularly among adolescents and young adults. Traditionally associated with pharyngitis, this organism is increasingly recognized for its involvement in systemic infections, including bacteremia, central nervous system abscesses, and Lemierre's syndrome. The pathogenicity of A. haemolyticum is attributed to its production of hemolysins and neuraminidase, facilitating tissue invasion and immune evasion. Clinically, infections often present with sore throat, fever, and a characteristic scarlatiniform rash, which can lead to their misdiagnosis as streptococcal pharyngitis. Severe manifestations, though rare, have been documented, particularly in immunocompromised individuals. Diagnosis is challenging due to the organism's slow growth and potential misidentification as diphtheroids in cultures. Accurate identification necessitates specific culture conditions and biochemical testing. Treatment typically involves beta-lactam antibiotics; however, the emergence of resistance patterns necessitate susceptibility testing to guide therapy. This review aims to consolidate current knowledge on A. haemolyticum, emphasizing its clinical presentations, diagnostic challenges, and management strategies, thereby enhancing recognition and treatment of infections caused by this emerging pathogen.