What organism is associated with an increased risk of contracting pneumonia in AIDS patients?

Pneumocystis jiroveci is a fungus that is notably associated with pneumonia in immunocompromised individuals, particularly those with AIDS. This organism can lead to Pneumocystis pneumonia (PCP), a serious and often life-threatening condition in patients whose immune systems are severely weakened. AIDS patients have significantly lower CD4 T-cell counts, which makes them particularly susceptible to infections that are typically not a risk for individuals with healthy immune systems.

Pneumocystis jiroveci is one of the most common opportunistic infections in patients with AIDS, and because these patients can have very low levels of immune response, they are at an increased risk for developing pneumonia caused by this organism. In managing patients with AIDS, it is common practice to monitor CD4 counts and provide prophylactic treatment to those at high risk of developing PCP, reinforcing the significance of pneumocystis as a critical pathogen in this population.

While other organisms such as Toxoplasma gondii, Mycobacterium avium, and Streptococcus pneumoniae are also associated with infections in patients with compromised immune systems, they do not specifically correlate with pneumonia in the same direct manner as Pneumocystis jiroveci does for AIDS patients