Pneumocystis jirovecii

Pneumocystis jirovecii is a yeast-like fungus of the genus Pneumocystis. The causative organism of Pneumocystis pneumonia, it is an important human pathogen, particularly among immunocompromised hosts. Prior to its discovery as a human-specific pathogen, P. jirovecii was believed to be the same species as the Pneumocystis organisms that infect other mammals.

Overview

Pneumocystis is a genus of yeast-like fungus. In humans, it can cause a lung infection known as Pneumocystis pneumonia (PCP). Pneumocystis jirovecii is the most common species found in humans. It is an opportunistic pathogen, meaning it takes advantage of weakened immune systems to cause disease.

Infection and Disease

Infection with P. jirovecii can lead to PCP, a serious illness that can be fatal, especially in those with weakened immune systems. Symptoms of PCP include fever, cough, and difficulty breathing. The disease can be diagnosed through a variety of tests, including microscopy and polymerase chain reaction (PCR).

Treatment and Prevention

Treatment for PCP often involves medications such as trimethoprim-sulfamethoxazole (TMP-SMX), dapsone, and pentamidine. Prevention strategies include prophylactic therapy for those at high risk of infection.

Epidemiology

P. jirovecii is found worldwide. It is most commonly seen in people with weakened immune systems, such as those with HIV/AIDS, those undergoing chemotherapy, and organ transplant recipients.

History

The organism was first described in 1909 by Carlos Chagas, and was later named after Otto Jirovec, who documented its pathogenic potential in humans in the 1950s.

See Also

• Pneumocystis
• Pneumocystis pneumonia
• Opportunistic infection
• Immunocompromised host

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  Pneumocystis jirovecii
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  Pneumocystis jirovecii