Pneumocystis jiroveci : still troublesome to diagnose and treat

Pneumocystis jiroveci pneumonia (PJP) poses an important risk in immunodeficient patients. Several aspects of the pathogenesis and management of PJP remain poorly understood. The aim of this review is to describe new trends and challenges in the diagnosis and treatment of PJP focused on non-HIV patients compared with patients living with HIV.

The immune response to Pneumocystis jiroveci infection varies among different host types and modifies clinical and radiological presentation. The performance of microbiological diagnostic tests depends on pretest probability according to baseline disease, clinical presentation, and radiological pattern. Real-time qualitative and quantitative PCR tests have been proposed as the optimal method for PJP diagnosis, but it is essential to interpret PCR results within the clinical context. Therapy of PJP has not changed substantially, but new options with low-dose trimethoprim/sulfamethoxazole and combination treatment with old and new antifungals are being explored. The use of complementary steroid treatment is well established in patients living with HIV but is controversial in non-HIV patients. Protocols for primary and secondary PJP prophylaxis are evolving. Evidence for nosocomial acquisition and possible person-to-person transmission of infection suggests the need for formal infection control policies.

Early diagnosis and treatment are crucial for improving the prognosis of PJP, but several challenges remain to be addressed. Future efforts should focus on developing new diagnostic methods, treatment options and risk stratification tools to improve prevention strategies.