• Archives of Pharmacal Research
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• v.25 no.3
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• pp.215-228
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• 2002

It is now more than two decades since the AIDS epidemic began with a cluster of Pneumocystis carinii pneumonia (PCP) in a community of homosexual men. Since then, many other infections have been characterized as opportunistic infections secondary to HIV infection. These include, but are not limited to, infections with Toxoplasma gondii, Cytomegalovirus (CMV), Mycobacterium avium complex (MAC), and Cryptococcus neoformans. Over the last two decades, there have been dramatic improvements in diagnosis, prevention and treatment of all these infections. As a result, in North America and Western Furope the rates of opportunistic infections secondary to AIDS have decreased substantially. We will review these common opportunistic infections below.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.174-182
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• 1997

Pneumocystis carinii pneumonia mainly occurs in immunocompromised patients and it is also known of major cause of death in children with acute lymphoblastic leukemia. After consolidation chemotherapy, acute lymphoblastic leukemia children is developed Pneumocystis carinii pneumonia frequently no an opportunistic infection but there were no controlled studies which have been performed to evaluate the usefulness of corticosteroid in Pneumocystis carinii pneumonia with acute lymphoblastic leukemia. We experienced a case of Pneumocystis carinii pneumonia in acute lymphoblastic leukemia with febrile neutropenic 6 years old girl. She was treated with trimethoprim-sulfamethoxazole and prednisone. We report this case with brief review of related literature.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.321-324
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• 2007

Pneumocystis (P.) carinii is an opportunistic fungal pathogen of many animal species and human, which can cause fatal pneumonia in immunocompromised individuals. Three 100-day-old pigs with progressive atrophy, anorexia and respiratory distress were submitted to the Cheju National University for diagnosis. Grossly, the lungs were enlarged with rubbery consistency. Histopathologically, the lungs were characterized by diffuse interstitial pneumonia with thickening of alveolar septa due to infiltration of macrophages and lymphocytes. Alveolar lumens were filled with a foamy eosinophilic proteinaceous material in which numerous punctiform organisms. The organisms were demonstrated as P. carinii by Grocott-methenamine-silver staining and immunohistochemistry in lungs of two pigs. In our best knowledge, this is believed to be the first report of P. carinii pneumonia in pigs in Korea.

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.465-469
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• 1998

Acute respiratory failure with diffuse pulmonary infiltration was occurred in a patient with malignant lymphoma 1month after the $8^{th}$ CHOP chemotherapy. The ground glass and consolidation appearances on chest C-T in this immunodeficient patient could be presented in many clinical situations such as pneumonia by opportunistic infections (fungal, parasites, viral, and usual bacterial pathogens), anti-tumor drug's pulmonary toxicity and tumor invasion. And the other diseases of acute interstitial pneumonitis, alveolar proteinosis, BOOP, puhnonary edema and alveolar hemorrhage, which could present the same radiological findings, should included in differential diagnosis. This patient was diagnosed as the opportunistic pneumonia by Pneumocystis carinii and probably Cytomegalovirus through bronchoalveolar lavage and transbronchial lung biopsy

• Childhood Kidney Diseases
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• v.24 no.1
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• pp.47-52
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• 2020

Pneumocystis pneumonia (PCP) is a rare disease in healthy people but a potentially fatal opportunistic infection by Pneumocystis jirovecii in immunocompromised patients with organ transplantation. We present three cases of PCP after kidney transplantation in pediatric patients. First case was a 4-year-old boy diagnosed with Denys-Drash syndrome and received living-donor kidney transplantation from his mother at age of 1. Second case was a 19-year-old male, with polycystic kidney disease, who received kidney transplantation from his mother at the age of 18. Third case was a 19-year-old female with chronic kidney disease of unknown etiology, who received kidney transplantation from her father at age of 15. These three patients who were on immunosuppressive therapy and completed of routine PCP prophylaxis for 6 months had presented with cough and dyspnea more than 1 year after transplantation. Chest x-ray all showed diffuse haziness of both lung fields, and bronchoalveolar lavage from bronchoscopy revealed Pneumocystisjirovecii infection. All patients showed clinical resolution with intravenous trimethoprim-sulfamethoxazole (TMP-SMX) therapy for at least 3 weeks and had continued secondary prophylaxis for another 6-12 months. This report suggests that clinicians should have suspicion for the possibilities of opportunistic infection such as PCP after kidney transplantation in children.

• Tuberculosis and Respiratory Diseases
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• v.79 no.2
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• pp.101-103
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• 2016

Nocardia species are aerobic, gram-positive pathogens found worldwide in soil. Nocardia is considered an opportunistic pathogen, and its infection mostly occurs in immunocompromised patients. We report a case of Nocardia farcinica induced mediastinitis and pneumonia that occurred in a 64-year-old male patient who had no significant medical history except for hypertension. He visited another hospital with a complaint of dyspnea and left chest wall pain. The symptoms arose 7 days ago without any trauma and they worsened. A mediastinal mass was found on computed tomography scan. After being transferred to our hospital for further evaluation, he was diagnosed with mediastinitis and pneumonia. As N. farcinica was found to be the causative organism by 16S rRNA sequencing, proper antibiotic therapy including trimethoprim/sulfamethoxazole was initiated immediately. After this, the patient improved and he was discharged. If an infection has a disseminating course, nocardiosis cannot be excluded even in immunocompetent patients. Once the diagnosis is established, prompt antibiotic therapy should be performed based on the severity.

• Tuberculosis and Respiratory Diseases
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• v.64 no.4
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• pp.309-313
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• 2008

Cytomegalovirus (CMV) pneumonia is a serious opportunistic infection in an immunocompromised host such as an AIDS patient or transplant recipient undergoing immunosuppressive therapy. Diffuse alveolar hemorrhage (DAH) is a relatively uncommon condition and it occurs most often in patients with systemic autoimmune disease. However, various types of infectious pneumonia with Mycoplsma hominis, Stenotrophomonas maltophilia and Pneumocystis jirovecii have been reported to be associated with the development of DAH. The association of CMV infection with the development of DAH has rarely been reported. We experienced a case of DAH associated CMV pneumonia and the patient was successfully treated with the use of antiviral agents and steroids.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.574-579
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• 1999

Cytomegaloviruses (CMVs) are ubiquitous but highly species-specific agents which commonly infect many animals, including humans. Cytomegalovirus (CMV) pneumonia has been one of the most important opportunistic infections in the immunocompromised host for those who have acquired immunodeficiency syndrome (AIDS) or who have received kidney, bone marrow or other organs. Cytomegalovirus infection has been known to be associated with congenital, infantile and adult nephrotic syndrome. We report a rare case of CMV pneumonia with nephrotic syndrome in a 62-year-old female who recovered fully with ganciclovir.

• Tuberculosis and Respiratory Diseases
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• v.83 no.2
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• pp.132-140
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• 2020

In human immunodeficiency virus (HIV)-infected patients, Pneumocystis jirovecii pneumonia (PCP) is a well-known opportunistic infection and its management has been established. However, PCP is an emerging threat to immunocompromised patients without HIV infection, such as those receiving novel immunosuppressive therapeutics for malignancy, organ transplantation, or connective tissue diseases. Clinical manifestations of PCP are quite different between patients with and without HIV infections. In patients without HIV infection, PCP rapidly progresses, is difficult to diagnose correctly, and causes severe respiratory failure with a poor prognosis. High-resolution computed tomography findings are different between PCP patients with HIV infection and those without. These differences in clinical and radiological features are due to severe or dysregulated inflammatory responses that are evoked by a relatively small number of Pneumocystis organisms in patients without HIV infection. In recent years, the usefulness of polymerase chain reaction and serum β-D-glucan assay for rapid and non-invasive diagnosis of PCP has been revealed. Although corticosteroid adjunctive to anti-Pneumocystis agents has been shown to be beneficial in some populations, the optimal dose and duration remain to be determined. Recent investigations revealed that Pneumocystis colonization is prevalent and that asymptomatic carriers are at risk for developing PCP and can serve as the reservoir for the spread of Pneumocystis by airborne transmission. These findings suggest the need for chemoprophylaxis in immunocompromised patients as well as infection control measures, although the indications remain controversial. Because a variety of novel immunosuppressive therapeutics have been emerging in medical practice, further innovations in the diagnosis and treatment of PCP are needed.

• Journal of Microbiology and Biotechnology
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• v.34 no.8
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• pp.1609-1616
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• 2024

The Burkholderia cepacia complex (Bcc) consists of opportunistic pathogens known to cause pneumonia in immunocompromised individuals, especially those with cystic fibrosis. Treating Bcc pneumonia is challenging due to the pathogens' high multidrug resistance. Therefore, inhalation therapy with tobramycin powder, which can achieve high antibiotic concentrations in the lungs, is a promising treatment option. In this study, we investigated potential mechanisms that could compromise the effectiveness of tobramycin therapy. By selecting for B. cenocepacia survivors against tobramycin, we identified three spontaneous mutations that disrupt a gene encoding a key enzyme in the biosynthesis of cobalamin (Vitamin B₁₂). This disruption may affect the production of succinyl-CoA by methylmalonyl-CoA mutase, which requires adenosylcobalamin as a cofactor. The depletion of cellular succinyl-CoA may impact the tricarboxylic acid (TCA) cycle, which becomes metabolically overloaded upon exposure to tobramycin. Consequently, the mutants exhibited significantly reduced reactive oxygen species (ROS) production. Both the wild-type and mutants showed tolerance to tobramycin and various other bactericidal antibiotics under microaerobic conditions. This suggests that compromised ROS-mediated killing, due to the impacted TCA cycle, underlies the mutants' tolerance to bactericidal antibiotics. The importance of ROS-mediated killing and the potential emergence of mutants that evade it through the depletion of cobalamin (Vitamin B₁₂) provide valuable insights for developing strategies to enhance antibiotic treatments of Bcc pneumonia.