Opportunist Coinfections by Nontuberculous Mycobacteria and Fungi in Immunocompromised Patients

Abstract

Nontuberculous mycobacteria (NTM) and many fungal species (spp.) are commonly associated with opportunistic infections (OPIs) in immunocompromised individuals. Moreover, occurrence of concomitant infection by NTM (mainly spp. of Mycobacterium avium complex and Mycobacterium abscessus complex) and fungal spp. (mainly, Aspergillus fumigatus, Histoplasma capsulatum and Cryptococcus neoformans) is very challenging and is associated with poor patient prognosis. The most frequent clinical symptoms for coinfection and infection by single agents (fungi or NTM) are similar. For this reason, the accurate identification of the aetiological agent(s) is crucial to select the best treatment approach. Despite the significance of this topic it has not been sufficiently addressed in the literature. This review aims at summarizing case reports and studies on NTM and fungi coinfection during the last 20 years. In addition, it briefly characterizes OPIs and coinfection, describes key features of opportunistic pathogens (e.g., NTM and fungi) and human host predisposing conditions to OPIs onset and outcome. The review could interest a wide spectrum of audiences, including medical doctors and scientists, to improve awareness of these infections, leading to early identification in clinical settings and increasing research in the field. Improved diagnosis and availability of therapeutic options might contribute to improve the prognosis of patients’ survival.

X-linked immunodeficient (XID) mice exhibit high susceptibility to Cryptococcus gattii infection

“…Furthermore, the worsening of cryptococcosis is related to a weakened immunity by pre-existing conditions or co-infections. Showing that the malfunction of determinants of the immune system corroborate for a higher mortality and susceptibility to cryptococcosis 64 . Therefore, the absence of the B-1 cell component in the XID mice characterizes the loss of cells that are very important for infection resolution 24 , 25 , 38 , 65 , which justify the worsening of the clinical score that has been observed previously using C. neoforomans 66 , and now with C. gattii .…”

Immune Privilege: The Microbiome and Uveitis

“…Only when the global circulating T cell numbers, which includes Teff, TRM and Treg cells decline below 200 cells/ml and especially when they are less than 50 cells/ml, do latent infections, including those acquired in early life, become active infections and spread through the tissues (79,80). This is particularly so for viral infections, such as CMV, HSV and varicella zoster virus (VZV) but also for infections acquired in adulthood which were held in check by the immune system such as Mycobacterium tuberculosis (Mtb) and Toxoplasma gondii (81)(82)(83). Even more convincing is that opportunistic infections by pathogens which would normally present no threat to the host, and in many cases would be regarded as "commensals," come to the fore, particularly as brain and retinal infections, when T cell immunity in particular is compromised (e.g.…”

Coinfecção entre HIV e Histoplasma capsulatum

“…Embora a histoplasmose ocorra globalmente, esta micose é mais freqüentemente vista nas Américas e algumas regiões da Ásia e da África (Joao et al, 2020). No continente americano, ocorrem cerca de 15.000 novas infecções e 9.000 mortes entre pessoas que vivem com HIV (Perez et al, 2021).…”

“…Essas infecções são importantes causa de morbimortalidade em indivíduos imunocomprometidos. O tipo e gravidade do defeito imunológico determina o perfil do potencial agente etiológico e a infecção oportunista (Joao et al, 2020;Kuate et al, 2021).…”

“…Duas preocupações principais são destacadas em relação às infecções fúngicas: o aumento das taxas de fungos multirresistentes e o forte potencial para colonizar o hospedeiro e participar de infecções polimicrobianas, principalmente com bactérias (Joao, Bujdáková, & Jordao, 2020). O H. capsulatum apresenta diversos fatores de virulência que favorecem a adesão fúngica, colonização, disseminação e habilidade para sobreviver a ambientes desfavoráveis driblando os mecanismos de defesa do sistema imunológico do hospedeiro.…”