SESSION TITLE: Infectious Disease Student/Resident Case Report Posters II
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Streptococcus anginosus species were initially identified from a dental abscess. While a normal component of the oral cavity and GI tract, they are uncommonly identified as virulent pulmonary pathogens. These pathogens have the unique ability to form abscesses.
CASE PRESENTATION: A 53 year-old African American female with past medical history of FSGS, rheumatoid arthritis, OSA, CKD, and secondary hyperparathyroidism presented with a chief complaint of acute shortness of breath. She also reported chest pain, productive cough with hemoptysis, and fever. Her home medications included cyclosporine and prednisone. On presentation her physical exam was within normal limits with the exception of crepitance over the right chest wall. Laboratory abnormalities included leukocytosis (WBC 12,500) and anemia (hematocrit 28.5%). CT thorax showed multiple, bilateral pulmonary nodules. The patient underwent a needle core biopsy of her right lung mass. Biopsy results showed extensive intra-alveolar fibrin deposition with associated hemorrhage. There were acute inflammatory cells in the alveoli consistent with pneumonia. No evidence of neoplasm or granulomas. AFB and GMS stains were negative for any organisms. Three days later the patient underwent an open lung biopsy with right upper lobe wedge resection. The pathology showed acute necrotizing and organizing pneumonia consistent with an infectious etiology. The biopsy specimen revealed focally severe neutrophilic inflammation within the airspace and interstitium accompanied by abundant airspace fibrin. The culture from the surgical biopsy specimen grew streptococcus anginosus.
DISCUSSION: The streptococcus anginosus group (also known as the streptococcus milleri group) is a subgroup of viridans streptococcus. One of the unique characteristics of the streptococcus agninosus group is their tendency to form abscesses. These bacteria are poor stimulators of chemotaxis and are capable of surviving phagocytosis, promoting their ability to form abscesses. Thoracic infections include pneumonia, lung abscesses, empyema, and mediastinitis and carry significant morbidity and mortality. Treatment of these infections requires abscess drainage and antimicrobial therapy, usually a third generation cephalosporin, a beta-lactam/beta-lactamase inhibitor, or a carbapenem. The duration of therapy depends on clinical response, but typically four weeks of IV antibiotics is sufficient.
CONCLUSIONS: Streptococcus anginosus should always be considered true pathogens when grown in culture and requires abscess drainage and a long course of antibiotics.
Reference #1: Ruoff KL. Streptococcus Anginosus (“Streptococcus Milleri”): the unrecognized pathogen. Clin Microbiol Rev. 1988;1(1):102
Reference #2: Parker MT, Ball LC. Streptococci and aerococci associated with systemic infection in man. J Med Microbiol. 1976;9(3):275
Reference #3: Marinella MA, Harrington GD, Standiford T. Empyema necessitans due to Streptocci milleri. J Clin Infect Dis. 1996;23(1):203
DISCLOSURE: The following authors have nothing to disclose: Scott Duncan, Dipen Kadaria
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