Pneumocystis jirovecii in HIV patients and suspected pneumonia: a problematic diagnosis in Caracas, Venezuela

Abstract

Pneumocystis jirovecii pneumonia (PCP) is one of the most frequentopportunistic infections in immunocompromised patients. The objective of thisstudy was to know the P. jirovecii epidemiology in Venezuelan patients with HumanImmunodeficiency Virus (HIV) infection and suspected pneumonia, through passivesurveillance at a national reference laboratory during six years. Laboratory recordsof patients with HIV infection, who were hospitalized with acute lower respiratorytract infection (ALRTI), and presumptive clinical diagnosis of PCP, were reviewedbetween January 2007 and December 2012, at the Mycology Department of theInstituto Nacional de Higiene Rafael Rangel. Several respiratory specimens werereceived and the direct immunofluorescence assay (DIF) and nested polymerasechain reaction (nPCR) diagnostic techniques were used. One hundred and sixty-onerespiratory samples were processed and P. jirovecii was detected in 76 samples byDIF and in 20 by nPCR. PCP’s frequency in Venezuelan patients with HIV is high andit has been sustained throughout time. Colonization by P. jirovecii has uncertainclinical significance, but this study provides evidence that the state of advancedimmunosuppression increases the probability of colonization. DIF and nPCR arevery useful techniques for PCP diagnosis, but are of limited access in many hospitalcenters, especially in developing countries. We recommend the use of DIF with spontaneoussputum specimens as the first diagnostic line for PCP in patients with HIVinfection. The results obtained by nPCR should be interpreted with caution, takinginto account the patient’s clinical symptoms.