Icenhour C R, Rebholz S L, Collins M S, Cushion M T
Department of Infectious Disease, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0560, USA.
J Clin Microbiol. 2001 Oct;39(10):3437-41. doi: 10.1128/JCM.39.10.3437-3441.2001.
The genus Pneumocystis contains a family of fungal organisms that infect a wide variety of mammalian species. Although it is a cause of pneumonia in immunocompromised hosts, recent evidence suggests that these organisms colonize nonimmunosuppressed hosts. Detection of cryptic colonization with Pneumocystis becomes important in animal studies when infection-free animals are necessary. Provocation by chronic immunosuppression, histology, and serology has been widely used to detect the presence of Pneumocystis in rat colonies, requiring lengthy time periods and/or postmortem tissue. We conducted a study to evaluate the use of PCR amplification of oral swabs for the antemortem detection of Pneumocystis in 12 rat groups from three commercial vendors. Sera were collected upon arrival, and the oral cavity was swabbed for PCR analysis. Ten of these groups of rats were then housed in pairs under barrier and immunosuppressed to provoke Pneumocystis growth. Once moribund, the rats were sacrificed, and the lungs were collected to evaluate the presence of Pneumocystis by PCR and microscopic enumeration. DNA was extracted from oral swabs and lung homogenates, and PCR was performed using primers targeting a region within the mitochondrial large-subunit rRNA of Pneumocystis carinii f. sp. carinii. Upon receipt, 64% of rats were positive for P. carinii f. sp. carinii-specific antibodies, while P. carinii f. sp. carinii DNA was amplified from 98% of oral swabs. Postmortem PCR analysis of individual lungs revealed P. carinii f. sp. carinii DNA in all rat lungs, illustrating widespread occurrence of Pneumocystis in commercial rat colonies. Thus, oral swab/PCR is a rapid, nonlethal, and sensitive method for the assessment of Pneumocystis exposure.
肺孢子菌属包含一类真菌生物，可感染多种哺乳动物物种。尽管它是免疫功能低下宿主肺炎的病因，但最近的证据表明这些生物也可定植于非免疫抑制宿主。在需要无感染动物的动物研究中，检测肺孢子菌的隐匿定植变得很重要。长期免疫抑制、组织学和血清学激发法已被广泛用于检测大鼠群体中肺孢子菌的存在，这需要较长时间和/或尸检组织。我们进行了一项研究，以评估在来自三个商业供应商的12组大鼠中，使用口腔拭子的PCR扩增进行肺孢子菌生前检测的情况。到达时采集血清，并擦拭口腔进行PCR分析。然后将其中10组大鼠成对饲养在屏障环境中并进行免疫抑制以激发肺孢子菌生长。一旦濒死，就处死大鼠并收集肺部，通过PCR和显微镜计数评估肺孢子菌的存在。从口腔拭子和肺匀浆中提取DNA，并使用靶向卡氏肺孢子菌f. sp. carinii线粒体大亚基rRNA内一个区域的引物进行PCR。收到时，64%的大鼠卡氏肺孢子菌f. sp. carinii特异性抗体呈阳性，而98%的口腔拭子中扩增出了卡氏肺孢子菌f. sp. carinii DNA。对个体肺组织的死后PCR分析显示，所有大鼠肺组织中均有卡氏肺孢子菌f. sp. carinii DNA，说明商业大鼠群体中肺孢子菌广泛存在。因此，口腔拭子/PCR是一种快速、非致死且敏感的评估肺孢子菌暴露的方法。
