Evaluation of pulmonary microsporidiosis in iatrogenically immunosuppressed patients.

BACKGROUND

Microsporidia spp. are ubiquitous and infect a wide variety of intervertebrates and vertebrates, including humans. Pulmonary microsporidiosis, characterized by nonspecific symptoms like fever, cough and dyspnea, is often overlooked in the differential diagnosis of pulmonary infections in immunsupressed patients. In this study, we aimed to determine the prevalence of pulmonary microsporidiosis in iatrogenically immunosuppressed patients and to evaluate the patient characteristics.

METHODS

Bronchoalveolar lavage (BAL) specimens from 63 iatrogenically immunosuppressed patients and 28 controls were examined with PCR. By using PMP1 and PMP2 common primers specifically designed for Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon cuniculi and Encephalitozoon hellem small-subunit ribosomal DNA (SSU-rDNA) regions at 250-279 bp were amplified. In addition, PCR positive BAL specimens were examined with modified trichrome staining method for Microsporidia spores.

RESULTS

Out of 63 immunosuppressed patients, nine (14.2%) had Microsporidia spp., but none of the control patients had Microsporidia spp. on PCR. This difference between two groups was statistically significant (χ² =4.439; p=0.035). On the other hand there was not a statistically significant relationship between PCR positivity and patient characteristics such as gender and age. Of nine patients with Microsporidia PCR positive, only one had spores of Microsporidia sp. Out of eight patients without spores, one had Mycobacterium tuberculosis, one patient had Klebsiella pneumoniae and five patients had Pneumocystis jirovecii DNA.

CONCLUSIONS

This is the first study to evaluate the pulmonary microsporidiosis in immunosupressed patients in Turkey. The results of the study indicated that Microsporidia spp. should be taken into account in the differential diagnosis of pulmonary infections in immunosupressed patients and it is important to use molecular methods such as PCR in the laboratory diagnosis of the causative agent.