Which organism is commonly associated with pneumonia in patients with late HIV?

Pneumocystis jirovecii is a key pathogen in pneumonia among patients with late-stage HIV infection. This organism is a fungus that causes Pneumocystis pneumonia (PCP), which is particularly problematic in individuals who have a significantly compromised immune system, such as those with a CD4 count below 200 cells/mm³. In late HIV, patients are at high risk for opportunistic infections due to their weakened immune status, making them susceptible to this specific type of pneumonia.

PCP is notable for its association with the immunocompromised state caused by HIV, and it often presents with symptoms such as a dry cough, dyspnea, and hypoxemia. The diagnosis typically involves imaging studies, such as chest X-rays or CT scans, and can be confirmed with special staining of induced sputum or bronchoalveolar lavage fluid.

Other organisms can cause pneumonia in late-stage HIV, but Pneumocystis jirovecii is the most classic and recognized pathogen associated with this opportunistic condition, especially in the absence of antiretroviral therapy. Recognition and treatment of PCP are crucial in managing patients with advanced HIV to prevent severe respiratory complications and improve overall outcomes.