1. 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.