Prevalence of Positive DNA of Pneumocystis Jirovecii and of Cytomegalovirus in Bronchial Wash Fluid of Patients Undergoing Fiberoptic Bronchoscopy

Both Pneumocystis Jirovecii (Pneumocystic Carinii Pneumonia, PCP) and Cytomegalovirus (CMV) are opportunistic pathogens known to cause infection in patients with impaired immune systems. PCP is a frequent pathogen causing respiratory tract infections in Acquired Immune Deficiency (AIDS) patients, but may also cause infection in other immunecompromised hosts. CMV is a causative agent of pneumonia mostly in transplant recipients.

For CMV pneumonia to be diagnosed in a patient with clinical signs of pneumonia, it is necessary to demonstrate the presence of the virus by its isolation, histopathologic testing, immunohistochemical analysis, or in situ hybridization. Detection of viral DNA in respiratory secretions (eg. Bronchial wash) may be too sensitive and is considered insufficient for diagnosis. However, the diagnostic methods are either not commonly performed or, in the case of histopathology, may risk severely ill patients. It is not known how often viral DNA is indeed detected in respiratory secretions of immunocompetent and immunocompromized hosts.

As for PCP, it is not known whether an asymptomatic carriage state exists for this pathogen. It has been suggested that PCP may be found in bronchial washings of asymptomatic patients, mostly corticosteroid- treated , and pregnant women. This finding has not been confirmed by other investigators, nor is it known what the prevalence of PCP colonization is in Israel. If PCP colonization is common, detection of PCP DNA in bronchial wash may represent colonization, not infection, and may mask true infection by an unidentified pathogen. Thus, it is of importance to define the prevalence of PCP in respiratory secretions in our population.

Bronchial washing is a procedure routinely performed during Fiberoptic Bronchoscopy, which includes the instillation of 10-20 ml sterile saline solution into a segmental or subsegmental bronchus. It is a safe procedure, which may rarely result in fever up to 38.5 up to a few hours after the procedure. Patients hypoxemic at room air (O2 Sat <90%) will be excluded from this study.

Study Procedures: