Investigation of Pneumocystis jirovecii colonization in patients with chronic pulmonary diseases in the People's Republic of China.
BACKGROUND
The detection of Pneumocystis jirovecii DNA in respiratory specimen from individuals who do not have signs or symptoms of pneumonia has been defined as colonization. The role of P. jirovecii colonization in the development or progression of various lung diseases has been reported, but little information about P. jirovecii colonization in patients is available in the People's Republic of China.


OBJECTIVE
To determine the prevalence of P. jirovecii colonization in patients with various pulmonary diseases, including the acute and stable stage of COPD, interstitial lung diseases, cystic fibrosis, and chronic bronchiectasis.


METHODS
A loop-mediated isothermal amplification (LAMP) and a conventional polymerase chain reaction (PCR) method for detecting P. jirovecii were developed. Ninety-eight HIV-negative patients who were followed-up and who had undergone bronchoscopy for diagnosis of various underlying respiratory diseases were included in the study. Sputa of these patients were analyzed with LAMP amplification of P. jirovecii gene. In addition, conventional PCR, Giemsa and Gomori's methenamine silver nitrate staining assays were applied to all specimens.


RESULTS
The sensitivity and specificity test showed that there was no cross-reaction with other fungi or bacteria in detecting the specific gene of P. jirovecii by LAMP, and the minimum detection limits by LAMP was 50 copies/mL. P. jirovecii DNA was detected in 62 of 98 (63.3%) sputa specimens by LAMP assay and 22.45% (22/98) by conventional PCR. However, no P. jirovecii cysts were found by Giemsa and Gomori's methenamine silver nitrate in all of gene-positive specimens.


CONCLUSIONS
The results of our study showed that prevalence of P. jirovecii colonization is particularly high in patients with chronic pulmonary diseases in the People's Republic of China, and the LAMP method is better for evaluation of the colonization of P. jirovecii in sputum specimen than conventional PCR.
Department of Obstetrics and Gynecology, Shengjing Hospital, China Medical University, Shenyang, People's Republic of China.
Dong-Dong
DD
Wang
Department of Microbiology and Parasitology, College of Basic Medical Science, China Medical University, Shenyang, People's Republic of China ; Richard King Mellon Foundation Institute for Pediatric Research, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA.
Ming-Quan
MQ
Zheng
Department of Microbiology and Parasitology, College of Basic Medical Science, China Medical University, Shenyang, People's Republic of China.
Nan
N
Zhang
Department of Microbiology and Parasitology, College of Basic Medical Science, China Medical University, Shenyang, People's Republic of China.
Chun-Li
CL
An
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D001999:Bronchoscopy; D002681:China / Q000453:epidemiology; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000145:classification* / Q000150:complications*; D008297:Male; D008875:Middle Aged; D016720:Pneumocystis Infections / Q000453:epidemiology*; D045363:Pneumocystis carinii / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology*; D055815:Young Adult
Pneumocystis jirovecii; chronic pulmonary diseases; colonization; loop-mediated isothermal amplification