Pneumocystis jirovecii is a frequent opportunistic pathogen in HIV/AIDS. The inability to culture this species prevents from acquiring deeper knowledge about its biology, drug susceptibility as well as the epidemiology of the disease that it produces. Pneumocystosis diagnosis in Cuba is suspected, based on the clinical and radiological findings which often lead to misdiagnosis since other microorganisms produce symptoms, signs and radiological patterns similar to this infection. Currently, the status on drug resistance is unknown and there are no means to evaluate the resistance to the recommended drugs. On the other hand, no studies on the distribution of P. jirovecii of genotypes in the country have been described. The results of the present study allows: a) to describe for the first time in the literature a new genotype of mitochondrial small RNA ribosomal subunit (160A/196T), b) to suggest a narrow circulation of the pathogen in Cuba; and c) to assume a very low prevalence of sulfamide resistance linked to mutations of P. jirovecii in our country. The results obtained constitute highly valuable knowledge of pneumocystosis in Cuba, as well as worldwide since they provide new information that can be used to a better disease management.

Pneumocystis jirovecii es un agente patógeno oportunista que frecuentemente afecta a los enfermos con el VIH/sida. La imposibilidad de su cultivo limita el conocimiento profundo de su biología, susceptibilidad a los fármacos, y la epidemiología de la neumocistosis que provoca. En Cuba, se diagnostica mediante la información clínico-radiológica del paciente; pero esta puede ser inespecífica y acarrear errores, pues otros microorganismos provocan síntomas, signos y patrones radiológicos similares a los de esa infección. A su vez, no poder evaluar la resistencia a los medicamentos es un obstáculo en el tratamiento completo al paciente con VIH/sida. Ningún estudio describe la distribución de los genotipos de P. jirovecii en Cuba. Los resultados que se presentan a) revelan un nuevo genotipo (160A/196T) del gen que codifica para la subunidad menor del ARNr, b) sugieren una circulación restringida del agente patógeno en Cuba, c) e indican que la prevalencia de P. jirovecii con mutaciones vinculadas con su resistencia a sulfamidas es muy baja en nuestro medio. Tales resultados son de extraordinario valor no solo para el conocimiento de la neumocistosis en Cuba y en el mundo, sino también para el tratamiento integral a pacientes con VIH/sida.

First recognised as "schizonts" of Trypanosoma cruzi, Pneumocystis organisms are now considered as part of an early-diverging lineage of Ascomycetes. As no robust long-term culture model is available, most data on the Pneumocystis cell cycle have stemmed from ultrastructural images of infected mammalian lungs. Although most fungi developing in animals do not complete a sexual cycle in vivo, Pneumocystis species constitute one of a few exceptions. Recently, the molecular identification of several key players in the fungal mating pathway has provided further evidence for the existence of conjugation and meiosis in Pneumocystisorganisms. Dynamic follow-up of stage-to-stage transition as well as studies of stage-specific proteins and/or genes would provide a better understanding of the still hypothetical Pneumocystislife cycle. Although difficult to achieve, stage purification seems a reasonable way forward in the absence of efficient culture systems. This mini-review provides a comprehensive overview of the historical milestones leading to the current knowledge available on the Pneumocystis life cycle.