Background: Rothia mucilaginosa, a gram-positive coccus member of the family Micrococcaceae, is considered part of the normal microflora of the human mouth and the upper respiratory tract. Although this organism is believed to be of low virulence, it is increasingly recognized as an opportunistic pathogen mostly affecting immunocompromised hosts.
Methods: The medical literature was reviewed and we found 19 published cases of R. mucilaginosa pneumonia. We also report on a case of pneumonia attributed to this microorganism in a patient with chronic obstructive pulmonary disease (COPD).
Results: From January 1970 to August 2014, a total of 20 patients with R. mucilaginosa pneumonia were studied. Patients with haematologic malignancies (7/20), profoundly neutropenic with central line catheters (7/20) are at higher risk of developing the infection, while immunocompetent hosts with impaired pulmonary defences are less frequently affected (4/20). Beta-lactams or vancomycin alone or in combination with other antibiotics have been successfully used for the treatment of R. mucilaginosa pneumonia. The outcome was favourable in 18 cases. Only one fatality was attributed to the infection.
Conclusion: R. mucilaginosa should be considered in the diagnosis of pneumonia in both immunocompromised and immunocompetent hosts. Early diagnosis and timely administration of appropriate antibiotic treatment are necessary for cure.
Keywords: COPD; Rothia mucilaginosa; immunocompetent patient; pneumonia.