Molecular screening of Respiratory pathogens Case report: Unexpected cause of respiratory failure 3 days after heart transplantation K. Dierickx, A. Vankeerberghen, A. Boel, K. Van Vaerenbergh, H. De Beenhouwer Laboratory of Microbiology, OLVZ Aalst, Belgium CLINICAL PRESENTATION 56 year old female with history of non-ischemic cardiomyopathy No diabetes, non smoker Underwent heart transplantation (HTx) No signs of respiratory tract disease at the time of hospitalization for HTx Respiratory insufficiency starting three days post-transplantation Rx 3 days post HTx DIAGNOSIS Respiratory sample: 3days, 15 days and 35 days post-HTx Gram staining Bacterial culture Molecular diagnostics: respiratory panel of 8 in-house multiplex RT-PCR’s for the simultaneous detection of 22 pathogens (both viral and atypical bacterial infections). (See table 1) Molecular screening of Respiratory pathogens Viral panel Bacterial panel RSV-A and RSV-B Chlamydia pneumoniae hMPV Mycoplasma pneumoniae influenza A Bordetella pertussis influenza B Bordetella parapertussis Parainfluenza 1, 2, 3 and 4 Bordetella holmesii Rhinovirus Enterovirus 229E, HKU1, OC43 and NL63   Adenovirus Bocavirus Table 1: Respiratory pathogens detected with in-house multiplex RT-PCR panel RESULTS 3 days post HTx: acute respiratory failure, high fever. bronchial aspirate Gram stain: neutrophils +++ Culture: negative Molecular testing: Respiratory syncytial virus (RSV) positive with high viral load (Ct value: 23) 15 days post HTx: continued respiratory failure with bilateral “white lungs”. tracheal aspirate Gram stain: neutrophils + Culture: oropharyngeal flora ++ Molecular testing: RSV positive with high viral load (Ct value 25) 35 days post HTx: very slow resolution of bilateral infiltrates, slow recuperation clinically. Molecular testing: RSV positive with decreasing viral load (Ct value 28) DISCUSSION Within 3 days post HTx the bronchial aspirate of the patient showed a high load of RSV. Rx shows diffuse bilateral infiltrates compatible with viral pneumonia. In figure 1 the seasonal appearance of RSV and monthly number of positive samples analyzed in the molecular lab is presented. The RSV season was exceptionally long that year and the lady had a visit of her young grandchildren 2 days before surgery. This together with the aggressive immunosuppressive treatment of the patient immediately after HTx can explain the fulminant and exceptionally long-lasting viral infection. Tx Date Figure 1: Yearly overview of positive samples analyzed in the molecular lab CONCLUSION Community-acquired RSV infection is the cause of the respiratory failure observed in this patient. Without viral screening no accurate diagnosis for the respiratory failure could have been made. This case illustrates the added value of molecular screening for respiratory tract infections in adult immunocompromised patients at the IC-unit.