Rothia mucilaginosa is an emerging opportunistic pathogen increasingly associated with prosthetic device infections. We report a case of R. mucilaginosa prosthetic  device endocarditis and review the literature of infections caused by this organism.

Case Presentation:

23 year old male with a history of polysubstance abuse presented to the emergency room with pleuritic chest pain of three weeks duration. ICD was placed at the age 12 for long QT syndrome with cardiac arrest at the age of 3. His  blood pressure was 100/60 mm of Hg , Pulse was 78/min, respirations were 20/min, temperature was  37.5 Celsius. Auscultation of the heart was normal with no murmurs or gallop rhythm. 

Trans-esophageal echocardiography showed normal left ventricular systolic function, with two wires in the right atrium with an adherent mass  measuring 2.7 x 1.0 cm, There was a small, mobile echodenisty noted to be attached to the posterior cusp of pulmonary valve.Chest CT was obtained and showed multiple cavitary lesions in the left upper lobe and other pleural based opacities in the superior left lower lobe.

Diagnosis of infective endocarditis associated with ICD lead with septic embolization was presumed. blood cultures were obtained prior to empirical therapy which showed no growth.

After 2 weeks of Antibiotics  and transfer to another facility where he Underwent device and lead extraction. Cultures from the lead were negative. Pathology of the infected lead was consistent with acute endocarditis and longstanding calcification. Bacterial PCR of the vegetation was positive for Rothia mucilaginosa.

ICD lead infections are treated for 4-6 weeks but there is no literature to guide us in this case since the organism recovered is unusual. Since patient did not wanted to stay in hospital for long term antibiotics  therefore we did a shorter course of IV (14 days) followed by an oral regimen.


Rothia mucilaginosa was formerly known as Staphylococcus salivarius and Micrococcus mucilaginosus. It was reclassified into a new genus belonging to the family Micrococcaceae in 2000  based on 16S rRNA sequencing. The organism is an oxidase-negative, catalase-variable Gram-positive bacterium. Gram staining reveals non-spore-forming, encapsulated Gram-positive cocci that can appear in pairs, tetrads, or irregular clusters.

*Rothia mucilaginosa is a facultative anaerobic bacterium which grows well on non selective media and in standard blood culture systems.

*R. mucilaginosa is a normal inhabitant of the human oral cavity and respiratory tract.

*It is an infrequent pathogen mostly affecting immunocompromised hosts such as those with cancer, HIV, alcoholism, diabetes or chronic liver disease.

*Risk factors include  IV drug abuse, valve disease, presence of prosthetic device.

*infections caused by this organism that have been described include bacteremia, endovascular infection, bone and joint infection and pulmonary infections, Endocarditis is by far the most commonly reported clinical manifestation caused by this organism. 


In summary, R. mucilaginosa is increasingly recognized as an emerging opportunistic pathogen associated with prosthetic device infections. It is difficult to identify and can easily be mistaken for staphylococci or streptococci. Prosthetic valve endocarditis is not uncommon. A combination of antibiotic therapy and prompt removal of the infected device is necessary. Physicians should be aware of this organism when treating patients infected with Gram-positive bacteria associated with prosthetic devices.