Molecular Typing Of Pneumocystis

Pneumocystis is likely transmitted through the respiratory route. The reservoir for P. jiroveci is unknown, but could include other human or environmental sources, whereas animal reservoirs are unlikely due to host specificity.[12] Serological studies suggest that a high proportion of healthy individuals has had a primary infection during childhood.[13] It is still debated whether PCP is caused by reinfection or reactivation of latent infection.

Development of a typing system for P. jiroveci is critical for investigating the transmission and epidemi ology of PCP. Clinical samples contain relatively small amounts of organisms mixed with host DNA, and pure extractions of the organism are difficult or impossible to obtain. Therefore, standard genetic methods such as karyotyping or random amplification of polymorphic DNA cannot be performed. Thus, investigation of the epidemiology has relied on PCR-based DNA sequence analysis.

Different sequence types of P. jiroveci have been identified in a number of genetic loci (Table 1). Because of the relatively low discriminatory power of several of these loci, alternatives were sought. The internal transcribed spacer (ITS) regions, ITS1 and ITS2, of the rRNA locus have been central to the study of genomic variations and taxonomic relationships in fungi and other species. In contrast to other fungi, Pneumocystis possesses only one

Table 1 Genes used in

the typing of P. jiroveci

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

Get My Free Ebook


Post a comment