Equidae pythiosis in Brazil and the world: a systematic review of the last 63 years (1960-2023).

This systematic review compiles reports of clinical pythiosis in horses, mules and donkeys from 1960 to 2023 worldwide, focusing on Brazil. We searched databases and included 71 articles detailing clinical characteristics, geographic distribution, epidemiology, diagnostic methods, therapies, and outcomes. The results showed that publications on equine pythiosis have significantly increased since 2010. Brazil reported the highest incidence, comprising 55% of cases, predominantly in the southern, northeastern, and central-western regions during summer and autumn. Cutaneous pythiosis was the most prevalent form, generally presenting as single lesions in the appendicular region, and affected females more than males. Diagnosis typically involved histopathology, used alone or with other methods. Various treatments have been employed, with surgery, often combined with chemotherapy and immunotherapy, being the most common. Notably, 80.84% of treated animals recovered, highlighting the effectiveness of these therapies in enhancing survival rates. The limitations of the study included the lack of data in published case reports, which made it difficult to collect and calculate epidemiological data. Additionally, we recognize that pythiosis in Brazil is underreported, since this disease does not have mandatory notification and several cases are not registered and/or reported in the literature. Lastly, it is hypothesized that equid pythiosis may be more widespread than currently known, and its real occurrence in Brazil remains uncertain.

Pythium insidiosum: In vitro oomicidal evaluation of telithromycin and interactions with azithromycin and amorolfine hydrochloride.

This study evaluated the repositioning of the ketolide antibacterial telithromycin (TLT) against the oomycete Pythium insidiosum and verified the combination of TLT and the antimicrobials azithromycin (AZM) and amorolfine hydrochloride (AMR), which have known anti-P. insidiosum activity. Susceptibility tests of P. insidiosum isolates (n = 20) against the drugs were carried out according to CLSI protocol M38-A2, and their combinations were evaluated using the checkerboard microdilution method. The minimum inhibitory concentrations were 0.5-4 µg/mL for TLT, 2-32 µg/mL for AZM, and 16-64 µg/mL for AMR. For the TLT+AZM combination, 52.75 % of interactions were indifferent, 43.44 % were antagonistic, and 9.70 % were synergistic. As for interactions of the TLT+AMR combination, 60.43 % were indifferent, 39.12 % were antagonistic, and 10.44 % synergistic interactions. This study is the first to evaluate the repositioning of the antibacterial TLT against mammalian pathogenic oomycetes, and our results show that its isolated action is superior to its combinations with either AZM or AMR. Therefore, we recommend including TLT in future research to evaluate therapeutic approaches in different clinical forms of human and animal pythiosis.

Oomicidal activity of polypyrrole nanoparticles against Pythium insidiosum.

This study evaluated in-vitro action of a new molecule, the polypyrrole nanoparticles (Ppy-NP), against Pythium insidiosum isolates using M38-A2/CLSI; the minimal inhibitory (MIC) and minimal oomicidal (MOC) concentrations were also determined. Additionally, changes in the hyphae wall of P. insidiosum CBS 575.85 treated with Ppy-NP were evaluated by scanning electron microscopy (SEM). The MIC100 and MOC for all isolates ranged from 8 to 32 µg mL-1, and the MIC90 and MIC50 were 16 µg mL-1. The SEM showed structural damage to the hyphae of P. insidisoum treated with Ppy-NP, as hyphae surfaces with less turgidity were found, thereby showing scaling and ruptures compared to the control (untreated hyphae). Our findings highlighted the anti-P. insidiosum properties of Ppy-NP proved to be a promising candidate for research using pythiosis experimental models.

Tremellomycetes isolated from organs of Columba livia.

Brain, lungs, and intestines of Columba livia captured in Brazil were analyzed for research on Tremellomycetes. Mycological culture presented the growth of colonies suggestive of Cryptococcus spp. in 11.60% (13/112) of the samples. Microscopy revealed capsulated yeast cells. Molecular analysis evidenced Papiliotrema flavescens, Naganishia diffluens, Filobasidium magnum, and Naganishia randhawae. Thermotolerance of Tremellomycetes isolates from brain and lung (n = 10) evidenced cell growth and viability at 37 °C. At 42 °C/24 h, these isolates showed viability, except for one P. flavescens isolate. Here, we report the first isolation of Tremellomycetes species from the brain and lungs of a healthy C. livia.

The study reported the first isolation of Tremellomycetes species, including P. flavescens, N. diffluens, F. magnum, and N. randhawae from the organs of domestic pigeons. All isolates expressed important virulence factors such as capsule and thermotolerance, indicating their pathogenic potential.