Pneumocystis, an important opportunistic fungal pathogen that parasitizes in multiple mammalian lungs, may cause life-threatening Pneumocystis pneumonia (PCP) and even death among immunocompromised individuals. With the rapid development of high-throughput sequencing and multi-omics technologies, systematic comparative analyses of genome, transcriptome, and whole-genome sequencing results demonstrate that Pneumocystis is a type of obligate biotrophic fungi, and requires obtaining nutrition from hosts. In addition, sexual reproduction is an essential process for Pneumocystis survival, production and transmission, and asexual reproduction facilitates Pneumocystis survival, which provides new insights into understanding of the whole developmental process of Pneumocystis in the host lung and inter-host transmission of Pneumocystis. This review summarizes the advances in the reproduction mode of Pneumocystis and underlying mechanisms, which provides insights into prevention and treatment of PCP, notably for the prophylaxis against nosocomial transmission of PCP.
Humans ; Lung/microbiology* ; Pneumocystis/genetics* ; Pneumonia, Pneumocystis/microbiology*

Pneumocystis carinii is a pulmonary pathogen of immunocompromised humans or other mammals. Its infection results from activation of organisms involved in latent infection or from new infection through the air. Almost all children are known to be infected within 2 to 4 years of birth, though prenatal transplacental transmission has not yet been demonstrated. In this study we observed experimental P. carinii infection in neonatal rats, thus investigating the possibility of transplacental vertical transmission by Diff-Quik staining of the lung impression smears and in-situ hybridization for lung sections. The positive rate of P. carinii infection in immunosuppressed maternal rats was 100%, but that in normal maternal rats was 0%. Cystic forms of P. carinii were observed in three of six 1-week old neonatal rats born of heavily infected mothers, but none of them was positive by in-situ hybridization. Five weeks after birth, cystic forms were detected in four neonatal rats. In the lobes of the lungs, no predilection site of P. carinii was recognized. Counts of cystic forms on smears and the reactivity of in-situ hybridization in the lungs of neonatal rats were significantly lower than in maternal rats. The present findings suggest that P. carinii is rarely transmitted through the placenta and proliferates less successfully in the lungs of neonatal rats than in mothers.
Animal ; Animals, Newborn/microbiology* ; Disease Transmission, Vertical* ; Female ; Immunocompromised Host ; Lung/microbiology ; Male ; Opportunistic Infections/transmission* ; Opportunistic Infections/complications ; Pneumocystis carinii/isolation & purification ; Pneumonia, Pneumocystis carinii/transmission* ; Pneumonia, Pneumocystis carinii/complications ; Pregnancy ; Rats ; Rats, Wistar

AIDS-Related Opportunistic Infections ; diagnosis ; microbiology ; Acquired Immunodeficiency Syndrome ; diagnosis ; microbiology ; Bronchoalveolar Lavage Fluid ; microbiology ; Female ; Humans ; Immunohistochemistry ; Male ; Methenamine ; Pneumocystis carinii ; isolation & purification ; Pneumonia, Pneumocystis ; diagnosis ; microbiology ; Polymerase Chain Reaction ; Silver Staining ; methods

In order to evaluate the diagnostic value of fibrotic bronchoscopy (FB) in the pulmonary infiltration following bone marrow transplantation (BMT), 18 patients with pulmonary complications after BMT from November 2003 to March 2006 were performed with FB. Bronchoalveolar lavage (BAL) and brushing were performed in patients who had received short-term empirical therapy without good response, and transbronchial lung biopsy (TBLB) was carried out in 3 cases. The results showed that 9 out of 10 cases with pulmonary infection, including bacterial pneumonia (n = 3), aspergillosis (n = 2), pneumocystis carinii pneumonia (n = 3) and viral infection (n = 1) were diagnosed by using FB. One case was diagnosed as tuberculosis after open lung biopsy following negative results from twice BAL. 2 out of 8 cases were diagnosed by TBLB as noninfectious pulmonary complications. In conclusion, FB, especially with BAL, is a safe and useful procedure for the evaluation of pulmonary complications, which is particularly suitable for diagnosis of pulmonary infection after BMT. Furthermore, TBLB should be recommended in order to avoid open lung biopsy, if the patients tolerate the operation.
Adolescent ; Adult ; Bone Marrow Transplantation ; adverse effects ; Bronchoalveolar Lavage Fluid ; microbiology ; parasitology ; Bronchoscopy ; Child ; Female ; Humans ; Lung Diseases ; diagnosis ; etiology ; Male ; Middle Aged ; Pneumonia ; diagnosis ; etiology ; microbiology ; Pneumonia, Pneumocystis ; diagnosis ; etiology ; microbiology ; Young Adult

A 50-year-old male visited the outpatient clinic and complained of fever, poor oral intake, and weight loss. A chest X-ray demonstrated streaky and fibrotic lesions in both lungs, and chest CT revealed multifocal peribronchial patchy ground-glass opacities with septated cystic lesions in both lungs. Cell counts in the bronchoalveolar lavage fluid revealed lymphocyte-dominant leukocytosis, and further analysis of lymphocyte subsets showed a predominance of cytotoxic T cells and few T helper cells. Video-assisted wedge resection of the left upper lobe was performed, and the histologic examination was indicative of a Pneumocystis jirovecii infection. Trimethoprim-sulfamethoxazole (TMP-SMX) was orally administered for 3 weeks; however, the patient complained of cough, and the pneumonia was aggravated in the follow-up chest X-ray and chest CT. Molecular studies demonstrated mutations at codons 55 and 57 of the dihydropteroate synthase (DHPS) gene, which is associated with the resistance to TMP-SMX. Clindamycin-primaquine was subsequently administered for 3 weeks replacing the TMP-SMX. A follow-up chest X-ray showed that the pneumonia was resolving, and the cough was also alleviated. A positive result of HIV immunoassay and elevated titer of HCV RNA indicated HIV infection as an underlying condition. This case highlights the importance of careful monitoring of patients with P. jirovecii pneumonia (PCP) during the course of treatment, and the molecular study of DHPS mutations. Additionally, altering the anti-PCP drug utilized as treatment must be considered when infection with drug-resistant P. jirovecii is suspected. To the best of our knowledge, this is the first case of TMP-SMX-resistant PCP described in Korea.
Anti-Bacterial Agents/*administration & dosage ; Drug Resistance, Bacterial ; Humans ; Lung/microbiology/radiography ; Male ; Middle Aged ; Pneumocystis jirovecii/*drug effects/genetics/isolation & purification/physiology ; Pneumonia/*drug therapy/immunology/microbiology/radiography ; Sulfamethoxazole/*administration & dosage ; Trimethoprim/*administration & dosage

We communicate the diagnosis by microscopy of a pulmonary coinfection produced by Cryptococcus neoformans and Pneumocystis jiroveci, from a respiratory secretion obtained by bronchoalveolar lavage of an AIDS patient. Our review of literature identified this coinfection as unusual presentation. Opportunistic infections associated with HIV infection are increasingly recognized. It may occur at an early stage of HIV-infection. Whereas concurrent opportunistic infections may occur, coexisting Pneumocystis jiroveci pneumonia (PCP) and disseminated cryptococcosis with cryptococcal pneumonia is uncommon. The lungs of individuals infected with HIV are often affected by opportunistic infections and tumours and over two-thirds of patients have at least one respiratory episode during the course of their disease. Pneumonia is the leading HIV-associated infection. We present the case of a man who presented dual Pneumocystis jiroveci and cryptococcal pneumonia in a patient with HIV. Definitive diagnosis of PCP and Cryptococcus requires demonstration of these organisms in pulmonary tissues or fluid. In patients with < 200/microliter CD4-lymphocytes, a bronchoalveolar lavage should be performed. This patient was successfully treated with amphotericin B and trimethoprim sulfamethoxazole. After 1 week the patient showed clinical and radiologic improvement and was discharged 3 weeks later.
Acquired Immunodeficiency Syndrome ; complications ; Adult ; Amphotericin B ; therapeutic use ; Antifungal Agents ; therapeutic use ; Bronchoalveolar Lavage Fluid ; microbiology ; Coinfection ; diagnosis ; pathology ; Cryptococcosis ; complications ; diagnosis ; pathology ; Cryptococcus neoformans ; isolation & purification ; Humans ; Male ; Microscopy ; Pneumocystis carinii ; isolation & purification ; Pneumonia, Pneumocystis ; complications ; diagnosis ; pathology ; Treatment Outcome ; Trimethoprim, Sulfamethoxazole Drug Combination ; therapeutic use

The radiologic findings of a single nodule from Pneumocystis jirovecii pneumonia (PJP) have been rarely reported. We described a case of granulomatous PJP manifesting as a solitary pulmonary nodule with a halo sign in a 69-year-old woman with diffuse large B cell lymphoma during chemotherapy. The radiologic appearance of the patient suggested an infectious lesion such as angioinvasive pulmonary aspergillosis or lymphoma involvement of the lung; however, clinical manifestations were not compatible with the diseases. The nodule was confirmed as granulomatous PJP by video-assisted thoracoscopic surgery biopsy.
Aged ; Antibodies, Monoclonal, Murine-Derived/adverse effects/therapeutic use ; Antineoplastic Agents/adverse effects/therapeutic use ; Antineoplastic Combined Chemotherapy Protocols/adverse effects/therapeutic use ; Biopsy/methods ; Cyclophosphamide/adverse effects/therapeutic use ; Doxorubicin/adverse effects/therapeutic use ; Female ; Humans ; Lymphoma, Large B-Cell, Diffuse/drug therapy/microbiology ; Pneumocystis jirovecii/pathogenicity ; Pneumonia, Pneumocystis/*diagnosis/*radiography ; Positron-Emission Tomography ; Prednisone/adverse effects/therapeutic use ; Solitary Pulmonary Nodule/*microbiology ; Thoracic Surgery, Video-Assisted ; Tomography, X-Ray Computed ; Vincristine/adverse effects/therapeutic use