Pneumocystis jirovecii colonization in non-HIV-infected patients based on nested-PCR detection in bronchoalveolar lavage samples

Pneumocystis jirovecii causes Pneumocystis pneumonia [PCP] in immunocompromised patients with a high rate of morbidity and mortality. Colonization with this fungus may stimulate pulmonary inflatnmation or lead to PCP in susceptible patients. The epidemiology of this infection and routs of its transmission has poorly studied in Iran. We examined Pnaumocystis colonization in patients with various lung underlying diseases. Bronchoalveolar lavage [BAL] fluids of 458 patients with different underlying diseases or pulmonary signs were collected between August 2010 and January 2012. Patients were divided into four groups: transplant recipients, malignant patients, immunosuppressive drug recipients and patients with other different lung diseases. A sensitive nested-PCR method targeted 18S ribosomal UNA gene was used for investigating P. jirovecii in the specimens. P. jirovecii DNA was detected in 57 out of 458 [12.5%] BAL samples by nested-PCR. Colonization rate in malignant patients, transplant recipients, immunosuppressive therapy recipients and patients with other various lung diseases was 21.7%, 20.3%, 12.7% and 7.3%, respectively. The enzyme BanI cuts all PCR products producing fragments with the size of 228 and 104 base pair. This finding as well as sequencing of four random positive samples validated and reconfirmed the PCR results. P. jirovecii cysts were found in 5 out of 57 PCR positive samples. A significant number of patients with pulmonary diseases were colonized by P. jirovecii that can develop to PCP in these patients or they may transmit the fungus to other susceptible patients

[ identification of nocardia in BAL specimens of bronchoscopic patients by using classical and molecular methods]

Nocardiosis is a rare and potentially life-threatening infection caused by several species of the Nocardia genus. The objective of this study was to develop and evaluate a rapid and new method to clinically identify relevant Nocardia species. Rapid and accurate diagnosis of Nocardia species is essential for the treatment of severe infections and prevention of cerebral abscess. One hundred and eighty patients, 103 [57.22%] male and 77 [42.78%] female, with severe symptomatic pulmonary infection were studied in the course of a 12-month period in Dr. Shariati Teaching Hospital affiliated to Tehran University of Medical Sciences in 2010. The specimens were cultured and identified using microbiological and biochemical tests. Polymerase chain reaction [PCR] was used to directly identify the organism in the broncoalveolar lavage samples collected from the patients. NG1 and NG2 primers were used to amplify a Nocardia genus-specific 598-bp fragment of 16S rRNA. Nineteen samples [10.56%] were positive with PCR and 5 samples [2.78%] with conventional methods. All samples with positive cultures were also positive by PCR. The results of this study showed that PCR has a high sensitivity and accuracy for the detection of Nocardia compared with culture and biochemical tests. Considering the rapidity, precision, high sensitivity and specificity of molecular techniques, use of these techniques is suggested in conjunction with conventional methods for the detection of Nocardia phenotypes in clinical laboratories and research centers