title: Loop-mediated isothermal amplification method for diagnosing Pneumocystis pneumonia in HIV-uninfected immunocompromised patients with pulmonary infiltrates.
abstract: Loop-mediated isothermal ampliﬁcation (LAMP) is becoming an established nucleic acid ampliﬁcation method offering rapid, accurate, and cost-effective diagnosis of infectious diseases. We retrospectively evaluated 78 consecutive HIV-uninfected patients who underwent LAMP method for diagnosing Pneumocystis pneumonia (PCP). Diagnosis of PCP was made by the detection of Pneumocystis jirovecii (P. jirovecii) with positive LAMP or conventional staining (CS) (Grocott methenamine silver staining or Diff-Quick™) on the basis of compatible clinical symptoms and radiologic findings. Additionally, we reviewed HIV-uninfected immunocompromised patients who underwent subcontract PCR as a historical control. LAMP was positive in 10 (90.9%) of 11 positive-CS patients. Among 13 negative-CS patients with positive LAMP, 11 (84.6%) had PCP, and the remaining 2 were categorized as having P. jirovecii colonization. LDH levels in negative-CS PCP were higher than in positive-CS PCP (p = 0.026). (1 → 3)-β-D-glucan levels in negative-CS PCP were lower than in positive-CS PCP (p = 0.011). The interval from symptom onset to diagnosis as PCP in LAMP group (3.45 ± 1.77 days; n = 22) was shorter than in subcontract PCR group (6.90 ± 2.28 days; n = 10; p < 0.001). As for patients without PCP, duration of unnecessary PCP treatment in LAMP group (2; 2-3 days; n = 10) was shorter than in subcontract PCR group (7; 7-12.25 days; n = 6; p = 0.003). LAMP showed higher sensitivity (95.4%) and positive predictive value (91.3%) than subcontract PCR did. Pneumocystis LAMP method is a sensitive and cost-effective diagnostic method and is easy to administer in general hospitals. In-house LAMP method would realize early diagnosis of PCP, resulting in improving PCP prognosis and reducing unnecessary PCP-specific treatment.
authors.affiliation: Department of Pulmonology, Kameda Medical Center, Japan. Electronic address: kei.7.nakashima@gmail.com.
authors.forename: Kei
authors.initials: K
authors.lastname: Nakashima
authors.affiliation: Department of Pulmonology, Kameda Medical Center, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Aoshima
authors.affiliation: Department of Pulmonology, Kameda Medical Center, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ohkuni
authors.affiliation: Clinical Research Support Division, Center for Health Research, Kameda College of Health Sciences, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Hoshino
authors.affiliation: Department of Laboratory Medicine, Kameda Medical Center, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Department of Laboratory Medicine, Kameda Medical Center, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Otsuka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004271:DNA, Fungal / Q000032:analysis / Q000235:genetics; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008875:Middle Aged; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D045363:Pneumocystis carinii / Q000235:genetics* / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology*; D012189:Retrospective Studies
chemical_list: D004271:DNA, Fungal
keywords: Loop-mediated isothermal amplification method; Pneumocystis jirovecii; Pneumocystis pneumonia