Helweg-Larsen Jannik, Jensen Jørgen Skov, Dohn Birthe, Benfield Thomas L, Lundgren Bettina
Copenhagen HIV Programme, Department of Infectious Diseases, Copenhagen, Denmark.
BMC Infect Dis. 2002 Nov 25;2:28. doi: 10.1186/1471-2334-2-28.
Pneumocystis jiroveci (formerly known as P. carinii f.sp. hominis) is an opportunistic fungus that causes Pneumocystis pneumonia (PCP) in immunocompromised individuals. Pneumocystis jiroveci can be detected by polymerase chain reaction (PCR). To investigate the clinical importance of a positive Pneumocystis-PCR among HIV-uninfected patients suspected of bacterial pneumonia, a retrospective matched case-control study was conducted.
Respiratory samples from 367 patients suspected of bacterial pneumonia were analysed by PCR amplification of Pneumocystis jiroveci. To compare clinical factors associated with carriage of P. jiroveci, a case-control study was done. For each PCR-positive case, four PCR-negative controls, randomly chosen from the PCR-negative patients, were matched on sex and date of birth.
Pneumocystis-DNA was detected in 16 (4.4%) of patients. The median age for PCR-positive patients was higher than PCR-negative patients (74 vs. 62 years, p = 0.011). PCR-positive cases had a higher rate of chronic or severe concomitant illness (15 (94%)) than controls (32 (50%)) (p = 0.004). Twelve (75%) of the 16 PCR positive patients had received corticosteroids, compared to 8 (13%) of the 64 PCR-negative controls (p < 0.001). Detection of Pneumocystis-DNA was associated with a worse prognosis: seven (44%) of patients with positive PCR died within one month compared to nine (14%) of the controls (p = 0.01). None of the nine PCR-positive patients who survived had developed PCP at one year of follow-up.
Our data suggest that carriage of Pneumocystis jiroveci is associated with old age, concurrent disease and steroid treatment. PCR detection of P. jiroveci has low specificity for diagnosing PCP among patients without established immunodeficiency. Whether overt infection is involved in the poorer prognosis or merely reflects sub-clinical carriage is not clear. Further studies of P. jiroveci in patients receiving systemic treatment with corticosteroids are warranted.
耶氏肺孢子菌（以前称为卡氏肺孢子菌人型变种）是一种机会性真菌，可在免疫功能低下的个体中引起肺孢子菌肺炎（PCP）。可通过聚合酶链反应（PCR）检测耶氏肺孢子菌。为了调查在疑似细菌性肺炎的未感染艾滋病毒患者中，肺孢子菌PCR阳性的临床重要性，进行了一项回顾性匹配病例对照研究。
对367例疑似细菌性肺炎患者的呼吸道样本进行耶氏肺孢子菌的PCR扩增分析。为了比较与耶氏肺孢子菌携带相关的临床因素，进行了病例对照研究。对于每例PCR阳性病例患者,从PCR阴性患者中随机选择4例PCR阴性对照，按照性别和出生日期进行匹配。
在16例（4.4%）患者中检测到肺孢子菌DNA。PCR阳性患者的年龄中位数高于PCR阴性患者（74岁对62岁，p = 0.011）。PCR阳性病例的慢性或严重合并症发生率（15例（94%））高于对照组（32例（50%））（p = 0.004）。16例PCR阳性患者中有12例（75%）接受过皮质类固醇治疗，而64例PCR阴性对照中有8例（13%）接受过皮质类固醇治疗（p < 0.001）。肺孢子菌DNA的检测与预后较差相关：PCR阳性患者中有7例（44%）在1个月内死亡，而对照组为9例（14%）（p = 0.01）。9例存活的PCR阳性患者在随访1年时均未发生PCP。
我们的数据表明，耶氏肺孢子菌的携带与老年、并发疾病和类固醇治疗有关。在没有明确免疫缺陷的患者中，PCR检测耶氏肺孢子菌对诊断PCP的特异性较低。尚不清楚明显感染是否与较差的预后有关，或仅仅反映亚临床携带情况。有必要对接受皮质类固醇全身治疗的患者中的耶氏肺孢子菌进行进一步研究。
