Disseminated Mycobacterium Avium Complex in an Adolescent with Perinatally-Acquired HIV Infection.

Mycobacterium avium complex (MAC) is the most frequent nontuberculous mycobacteria implicated in opportunistic infections that define acquired immunodeficiency syndrome. With highly active antiretroviral therapy, disseminated MAC (dMAC) has become a rare entity. This unique case of dMAC was diagnosed in an adolescent with newly diagnosed perinatally-acquired HIV infection whose initial CD4 cell count was severely depleted and viral load was extremely high. While maximized treatment regimen had not been able to control his dMAC, improvement was noted when granulocyte macrophage colony-stimulating factor (GM-CSF) was added. GM-CSF should be considered as an adjunctive therapy in patients with refractory dMAC.

Comparative Profile of Heme Acquisition Genes in Disease-Causing and Colonizing Nontypeable Haemophilus influenzae and Haemophilus haemolyticus.

Nontypeable Haemophilus influenzae (NTHI) are Gram-negative bacteria that colonize the human pharynx and can cause respiratory tract infections, such as acute otitis media (AOM). Since NTHI require iron from their hosts for aerobic growth, the heme acquisition genes may play a significant role in avoiding host nutritional immunity and determining virulence. Therefore, we employed a hybridization-based technique to compare the prevalence of five heme acquisition genes (hxuA, hxuB, hxuC, hemR, and hup) between 514 middle ear strains from children with AOM and 235 throat strains from healthy children. We also investigated their prevalences in 148 Haemophilus haemolyticus strains, a closely related species that colonizes the human pharynx and is considered to be nonpathogenic. Four out of five genes (hxuA, hxuB, hxuC, and hemR) were significantly more prevalent in the middle ear strains (96%, 100%, 100%, and 97%, respectively) than in throat strains (80%, 92%, 93%, and 85%, respectively) of NTHI, suggesting that strains possessing these genes have a virulence advantage over those lacking them. All five genes were dramatically more prevalent in NTHI strains than in H. haemolyticus, with 91% versus 9% hxuA, 98% versus 11% hxuB, 98% versus 11% hxuC, 93% versus 20% hemR, and 97% versus 34% hup, supporting their potential role in virulence and highlighting their possibility to serve as biomarkers to distinguish H. influenzae from H. haemolyticus. In summary, this study demonstrates that heme acquisition genes are more prevalent in disease-causing NTHI strains isolated from the middle ear than in colonizing NTHI strains and H. haemolyticus isolated from the pharynx.