Rothia mucilaginosa: A Surprising Culprit of Pneumonia in an Absolute Immunocompetent Patient

Introduction: Rothia mucilaginosa, a gram-positive coccus and typical resident of the oropharyngeal and upper respiratory system, has increasingly been recognized as a human pathogen since its first identification in 1978. While it commonly affects immunocompromised individuals, causing serious infections like endocarditis, septicemia, and pneumonia, infection in immunocompetent hosts is rare. This article presents a case of pneumonia caused by R. mucilaginosa in an immunocompetent individual. Case description: A 42-year-old male with no significant medical history presented with a persistent cough and high-grade fever. Investigations revealed elevated neutrophils, C-reactive protein (CRP), and high-resolution computed tomography (HRCT) thorax indicating multifocal consolidation. Empirical management with piperacillin-tazobactam and clindamycin was ineffective, leading to a switch to meropenem-sulbactam. Bronchoalveolar lavage (BAL) identified R. mucilaginosa, prompting cotrimoxazole therapy. The patient’s fever subsided, and inflammatory markers decreased. After a 2-week course and follow-up, the patient exhibited no symptoms or recurrence of infection and remained stable. Discussion: R. mucilaginosa primarily affects immunocompromised individuals or those with underlying comorbidities. Diagnosis requires careful specimen collection and identification techniques. Treatment is challenging due to variable antibiotic susceptibility, with vancomycin, third-generation cephalosporins, and rifampicin often used. The pathogen’s ability to cause pneumonia in healthy individuals without comorbidities remains unreported. Underreporting due to misidentification and the need for awareness among clinicians are significant concerns in managing R. mucilaginosa infections. Conclusion: R. mucilaginosa is a significant pathogen causing pneumonia in diverse patient groups. Without formal treatment guidelines, diagnosis relies on clinical experience. Early detection and appropriate antibiotic therapy are crucial for effective management.