The University of Louisville Journal of Respiratory Infections

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Streptococcus milleri group (SMG) also referred to as the Streptococcus anginosus group. These are Gram-positive, variable hemolysis, catalase negative, microaerophilic, non-motile facultative anaerobes which have been known to cause abscesses in humans. We report a case of empyema caused by Streptococcus anginosus in a patient with an unresolved pneumonia for over a month. In early October 2018, the patient presented to an emergency room with the complaints of shortness of air, productive cough, chills, subjective fever and weight loss for 4 weeks. A chest X-ray revealed a left lower lobe pneumonia. He was treated with 250 mg of azithromycin for 4 days. During a follow-up visit in November 2018, he reported having persistent symptoms. The chest CT revealed a localized pleural fluid collection at the left lower chest highly suggestive of empyema. He was prescribed 100mg of doxycycline for a month. However, he was admitted to the hospital a week later due to worsening symptoms. The microbiological cultures for sputum and blood were negative; however, pleural fluid cultures grew Streptococcus anginosus resistant to clindamycin and erythromycin. The patient was treated with broad spectrum antimicrobial regimen in conjunction with surgical management. Initially, the patient underwent CT guided placement of chest tube with instillation of Tissue Plasminogen Activator (TPA) for the drainage of pleural fluid followed Video-assisted Thoracoscopy with lateral decortication and drainage of empyema of the left lung due to persistence of complicated effusion. There was remarkable improvement in his symptoms, and he recovered subsequently. Our case highlights the infections caused by the Streptococcus milleri group (SMG) in individuals with an unresolved pneumonia. Such patients should be diagnosed accurately and treated aggressively with rapid and effective interventions.


The author(s) received no specific funding for this work.

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This work is licensed under a Creative Commons Attribution 4.0 License.



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