A Unique Case of Legionella and Streptococcus Pneumoniae Coinfection

Abstract

SESSION TITLE: Bacterial Infections 2 SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Community-acquired pneumonia (CAP) is a frequent cause of hospitalization in adults. Most cases of CAP are caused by a single pathogen, with Streptococcus pneumoniae (pneumococcus) identified most commonly. Alternatively, Legionella pneumophilia is a less common cause of CAP. Although co-infections have been previously described, presence of both pneumococcus and legionella together in CAP is rare. We present a patient with positive urinary antigens for both pneumococcus and Legionella pneumophilia serogroup 1 (Lp1), indicating an unusual co-infection. CASE PRESENTATION: An 80 year old female presented with fatigue, weakness and progressively worsening shortness of breath. She was noted to be tachypneic and hypoxic on room air. Blood work was significant for neutrophil-predominant leukocytosis, however, initial serum procalcitonin concentration was low and chest X-ray was only significant for hyper-inflated lungs. She was admitted for treatment of presumed COPD exacerbation but her respiratory status progressively worsened requiring non-invasive ventilatory support. Repeat serum procalcitonin was significantly elevated. Computed tomography (CT) scan of the chest without contrast was significant for bilateral lower lobes tree-in-bud opacities. Sputum cultures, blood cultures and streptococcus pneumonia and legionella pneumophilia urinary antigens were obtained and she was started on broad spectrum antibiotics. Blood cultures remained negative but surprisingly urinary antigens for both pneumococcus and Lp1 returned positive. Antibiotics were then de-escalated to levofloxacin. The patient’s clinical status improved and she was discharged home in stable condition after a one week hospital course. DISCUSSION: Although co-infections with S. pneumoniae and L. pneumophilia have been described, this appears to be only the second case where a co-infection for CAP was diagnosed on the basis of positive urinary antigens. Various studies have shown high specificity and positive predictive value of urinary antigens and, therefore, such tests should be used as diagnostic tools to identify causative organisms of pneumonia. CONCLUSIONS: This unique case of pneumococcus and Legionella co-infection demonstrates the importance of urinary antigens in patients hospitalized secondary to CAP in addition to sputum cultures and peripheral blood cultures. This approach will promote early institution of organism specific antibiotic therapy and foster antibiotic stewardship. Reference #1: Lionel A. Mandell, Richard G. Wunderink, Antonio Anzueto, John G. Bartlett, G. Douglas Campbell, Nathan C. Dean, Scott F. Dowell, Thomas M. File, Jr., Daniel M. Musher, Michael S. Niederman, Antonio Torres, Cynthia G. Whitney; Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia in Adults. Clin Infect Dis 2007; 44 (Supplement_2): S27-S72. doi: 10.1086/511159 DISCLOSURE: The following authors have nothing to disclose: Moeezullah Beg, Sara Loucks, Hamza Arif, Tiffany Dumont No Product/Research Disclosure Information