title: A Case of Pneumonia Caused by Pneumocystis jirovecii Resistant to Trimethoprim-Sulfamethoxazole.
abstract: 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.
authors.affiliation: Division of Pulmonology and Allergy, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Division of Infection, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Yong Kyun
authors.initials: YK
authors.lastname: Cho
authors.affiliation: Department of Radiology, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Yon Mi
authors.initials: YM
authors.lastname: Sung
authors.affiliation: Departement of Pathology, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Dong Hae
authors.initials: DH
authors.lastname: Chung
authors.affiliation: Division of Pulmonology and Allergy, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Jeong
authors.affiliation: Division of Pulmonology and Allergy, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Jeong-Woong
authors.initials: JW
authors.lastname: Park
authors.affiliation: Division of Pulmonology and Allergy, Gachon University Gil Medical Center, Incheon 405-760, Korea.
authors.forename: Sang Pyo
authors.initials: SP
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D024881:Drug Resistance, Bacterial; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D045363:Pneumocystis carinii / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D011014:Pneumonia / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology; D011859:Radiography; D013420:Sulfamethoxazole / Q000008:administration & dosage*; D014295:Trimethoprim / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D014295:Trimethoprim; D013420:Sulfamethoxazole
keywords: Pneumocystis jirovecii; clindamycin; drug resistance; primaquine; sulfamethoxazole; trimethoprim