Oz H S, Hughes W T
Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Microb Pathog. 1999 Aug;27(2):119-21. doi: 10.1006/mpat.1999.0292.
The diagnosis of Pneumocystis carinii pneumonia (PCP) requires invasive methods of bronchoalveolar lavage and lung biopsy. In this study, we examined efficacy of polymerase chain reaction (PCR) compared to Giemsa and silver ammoniacal staining to detect P. carinii in easily accessible extrapulmonary sites as well as lung. Samples were collected from lung, nasal and pharyngeal aspirates, gastric contents, urine and blood from dexamethasone treated or untreated virus-free Sprague-Dawley rats. All immunosuppressed lung samples were P. carinii positive by PCR analysis and both stains. Respectively DNA fragments of P. carinii were found in 93%, of nasal and 75% of pharyngeal aspirates, and 0% of sera, urine or gastric aspirates from immunosuppressed rats. However, no P. carinii cysts or trophozoites were found in nasal and pharyngeal aspirates (extrapulmonary sites) by silver ammoniacal or Giemsa staining. In comparison, none of the specimens from immunocompetent rats were PCR positive at any sites tested including the lungs. Therefore, PCR amplification products of nasal and pharyngeal aspirates showed that immunosuppressed rats with PCP can carry P. carinii DNA fragments in their upper respiratory tracts, but immunocompetent animals without PCP, are free of the organism and this suggests an approach to be investigated in humans with PCP.
卡氏肺孢子虫肺炎（PCP）的诊断需要采用支气管肺泡灌洗和肺活检等侵入性方法。在本研究中，我们将聚合酶链反应（PCR）与吉姆萨染色和银氨染色进行了比较，以检测在易于获取的肺外部位以及肺组织中的卡氏肺孢子虫。样本取自经地塞米松处理或未处理的无病毒斯普拉格-道利大鼠的肺、鼻腔和咽抽吸物、胃内容物、尿液和血液。通过PCR分析和两种染色方法，所有免疫抑制的肺样本均显示卡氏肺孢子虫呈阳性。在免疫抑制大鼠的鼻腔抽吸物中，分别有93%、咽抽吸物中有75%检测到卡氏肺孢子虫的DNA片段，而血清、尿液或胃抽吸物中均未检测到。然而，通过银氨染色或吉姆萨染色，在鼻腔和咽抽吸物（肺外部位）中未发现卡氏肺孢子虫囊肿或滋养体。相比之下，在包括肺在内的任何测试部位，免疫功能正常大鼠的标本均未检测出PCR阳性。因此，鼻腔和咽抽吸物的PCR扩增产物表明，患有PCP的免疫抑制大鼠在上呼吸道中可携带卡氏肺孢子虫DNA片段，但未患PCP的免疫功能正常动物体内则没有这种病原体，这提示了一种可在患有PCP的人类中进行研究的方法。
