''Lacazia'' is a genus of

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

containing the single species ''Lacazia loboi'', which is responsible for Lobo's disease. It is a member of the order

Onygenales The Onygenales are an order of fungi in the class Eurotiomycetes and division Ascomycota. The order's last common ancestor is estimated to have lived 150 million years ago. Onygenales can consume and break down keratin, the main component of th ...

Description and natural habitats

''Lacazia loboi'' is a yeast-like fungus that causes infection in humans and

bottle-nosed dolphin Bottlenose dolphins are aquatic mammals in the genus ''Tursiops.'' They are common, cosmopolitan members of the family Delphinidae, the family of oceanic dolphins. Molecular studies show the genus definitively contains two species: the common ...

s (''Tursiops truncatus'').

Aqueous An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be rep ...

environments appear to be mandatory for the

lifecycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia * Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring *Life-cycle hypothesis ...

of ''L. loboi''. It is

saprophytic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...

in water and is transmitted to the vulnerable host via contact. Infections due to ''L. loboi'' are mostly reported from

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

zones.

Species

The genus ''Lacazia'' contains a single species, ''Lacazia loboi''. While the name ''Loboa loboi'' is still frequently used to refer to the causative agent of lobomycosis, more recently, classification of the fungus in the genus ''Lacazia'' and conclusively, the name ''Lacazia loboi'' has been proposed by McGinnis et al.

Synonyms

See the summary of synonyms and teleomorph-anamorph relations for the ''Lacazia'' spp.

Pathogenicity and clinical significance

''L. loboi'' is the causative agent of a tropical mycosis, lobomycosis, which is characterized by mucocutaneous lesions, that are usually nodular, vegetating, verrucose, cauliflower-like and hyper- or hypopigmented. Lower extremities and the ears are most commonly involved. Nasal and labial lesions have rarely been reported.Collier, L., A. Balows, and M. Sussman. 1998. Topley & Wilson's Microbiology and Microbial Infections, 9th ed, vol. 4. Arnold, London, Sydney, Auckland, New York. Aquarium employees and farmers constitute most of the cases with lobomycosis. Occupations such as goldmining, fishing, and hunting also predispose to ''L. loboi'' infections. A previous cutaneous trauma, insect bite, or wound cut enhances the entry of the fungus through the skin via contact with infected surrounding, such as dolphins. No evidence shows person-to-person transmission of lobomycosis.

Macroscopic features

Attempts to grow ''L. loboi'' on artificial media have as yet been unsuccessful.

Microscopic features

Numerous yeast-like, round, thick-walled cells are visualized. Chains of yeast cells are typically formed. Little tube-like connections are visible between the yeast cells.

Histopathologic features

Granuloma and yeast-like cells (diameter: 5-12 µm) forming chains are observed. As well as tube-like connections between the cells, secondary buds may also be visualized. The cells may be phagocytosed by histiocytes or multinucleated giant cells. Periodic-Acid-Schiff (PAS), Gomori's-Grocott's, and Gridley's silver stains are used for examination of histopathological sections.

Comparisons

Cross-antigenicity has been detected between ''L. loboi'' and ''

Paracoccidioides brasiliensis ''Paracoccidioides brasiliensis'' is a dimorphic fungus and one of the two species that cause paracoccidioidomycosis (the other being ''Paracoccidioides lutzii).'' The fungus has been affiliated with the family Ajellomycetaceae (division Ascomyco ...

''.

Susceptibility

Since efforts to cultivate ''L. loboi'' have failed, no ''in vitro'' susceptibility data are available. Optional treatment of lobomycosis is surgical excision. Full excision of the lesion is required for clinical success. Repeated cryotherapy may also yield favorable clinical response. While there yet appears no optional medical therapy, clofazimine has been effective in some cases with lobomycosis.Restrepo, A. 1994. Treatment of tropical mycoses. J. Amer. Acad. Dermatol. 31:S91-102.

Sister taxon

It is a sister

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

to ''P. brasiliensis''.

References

{{Taxonbar, from=Q6468145 Onygenales