Classification of Cryptococcus? Pay attention to the characteristics of Cryptococcus Gert!

Source: WeChat public account→ out of bed medicine

Author: Detective

Overview of the disease

Cryptococcus is a soil fungus, a yeast fungus of Basidiomycetes, that is widely distributed in nature and is found in fruits, milk, soil, yellow honeycombs, certain grasses and plants, as well as pigeon dung and other bird feces; it can also be found in human skin, mouth and intestines.

Pigeons and some birds can be intermediate hosts for the bacterium, and pigeon breeders usually have Cryptococcus infections several times higher than in the general population.

Cryptococcus is a conditional pathogen that only causes disease when the host immunity is low, so Cryptococcus CNS infection can occur alone, more commonly in systemic immunodeficiency diseases, chronic failure diseases, such as

Acquired immunodeficiency syndrome (AIDS)

lymphosarcoma

Reticulocytic sarcoma

leukaemia

Hodgkin's disease

Multiple myeloma

Sarcoidosis

tuberculosis

diabetes

nephropathy

Lupus erythematosus

The skin and mucous membranes are the initial sites of infection, often invading the body from the respiratory tract, causing mild lung inflammation and spreading to the CNS by hematogenesis when the body's immunity declines.

Cryptococcus classification

According to the taxonomy revised in 2015, cryptococcus spp. includes 10 species.

Among them, the Cryptococcus neoformans species complex and the Cryptococcus gattii species complex are the main pathogenic bacteria, including 7 species, which can cause more than 90% of cryptococcosis.

In addition, the nearly 80% of non-nascent, non-Gert cryptococcus diseases, including nearly 80% of non-nascent cryptococcus diseases, have been reclassified and renamed Papiliotrema laurentii and Nagaganishia albida.

Cryptococcus neonas/Cryptococcus gertericus complex is divided into four serotypes (Serotype A, B, C, D), serotypes A and D are Cryptococcus neonastic complex, and serotypes B and C are called Cryptococcus Gerterii complex.

According to the 2015 revised taxonomy, the Cryptococcus neonas complex includes C. neoformans s. s. (formerly known as Gruby variety of Cryptococcus novelis) and C. neoformans Deneoformans (formerly known as neofloroccus neoflora variants).

The vast majority of HIV-associated Cryptococcus infections are caused by Infection of the Grubie variant of Cryptococcus neonasticus.

Characteristics of Cryptococcus Gert

The epidemiology, clinical manifestations, treatment goals, fatality rates, and neurological sequelae of Cryptococcal Gert are different from those of cryptococcus neosoccus complexes.

Compared with the Cryptococcus neonasum complex, the Infection of the Cryptococcus Gert is characterized by more severe inflammatory changes in the nervous system, higher intracranial pressure, serious complications, cryptococcoma, and poor prognosis.

Cryptococcus Gertert complexes are more likely to cause cryptococcal tumors and/or hydrocephalus than cryptococcal neonastic complexes.

The Cryptococcus Gerter complex is less sensitive to a variety of antifungal drugs than cryptococcus neonastic complexes and may originate from intracranial cryptococcomas.

Therefore, the neoflora Cryptococcus complex requires a longer antifungal therapy cycle (induction period takes an average of 6 weeks) and even surgical removal of the lesion.

bibliography:

1.Liu XZ，Wang QM，Goker M, et al. Towards an integrated phylogenetic classification of theT remellomycetes [J]. Stud Mycol, 2015，81 :85-147.

2. Xing Xiaowei, Zhang Jiatang Advances in the diagnosis of Cryptococcal meningitis. Chinese Journal of Mycology,Vol.15,No.6,2020.12.2020