Phylogenetic relationships of Brazilian isolates of Pythium insidiosum based on ITS rDNA and cytochrome oxidase II gene sequences

The present study aimed to evaluate the in vitro antimicrobial action of Origanum vulgare, Origanum majorana, Mentha piperita and Rosmarinus officinalis on Pythium insidiosum oomycete zoospores. The antimicrobial activity evaluation was performed by the broth microdilution method according to CSLI M38-A2 documentation adapted to phytopharmaceuticals. Twenty-two P. insidiosum isolates were evaluated, and the minimum inhibitory concentration was determined at 100% growth inhibition. All P. insidiosum isolates evaluated showed a minimum inhibitory concentration ranging from 0.05 to 1.75 mg/mL when O. vulgare oil was used and from 0.11 to 3.5 mg/mL for O. majorana, M. piperita and R. officinalis oils. The results obtained indicate that the essential oils tested showed antimicrobial activity on P. insidiosum, with O. vulgare essential oil showing the best performance. These findings emphasize the potential use of plant essential oils as control agents in P. insidiosum infections; further research, however, is needed so as the in vivo activity of these oils can also be evaluated.

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“…All samples used were identified by macro-and micromorphology and confirmed by PCR and DNA sequencing [12,13].…”

Section: Pythium Insidiosum Isolatesmentioning

confidence: 99%

In Vitro Susceptibility of Brazilian Pythium insidiosum Isolates to Essential Oils of Some Lamiaceae Family Species

et al. 2014

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“…This diversity in susceptibility testing techniques likely correlates with the diversity of MICs observed for P. insidiosum (see Table S2 in the supplemental material). The phylogenetic diversity, especially among the clinical isolates from the Americas and Asia (29)(30)(31), may be another factor that is related to the different susceptibility profiles of P. insidiosum.…”

mentioning

confidence: 99%

New Insights into the In Vitro Susceptibility of Pythium insidiosum

Loreto

Tondolo

Pilotto

et al. 2014

Antimicrob Agents Chemother

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bWe have determined the in vitro activity of several antibacterial and antifungal drugs against Pythium insidiosum using broth microdilution (BMD), disk diffusion, and Etest methods. The largest zones of inhibition (disk diffusion) and the lowest BMD and Etest MICs were observed for azithromycin, clarithromycin, linezolid, mupirocin, doxycycline, minocycline, and tigecycline. The in vitro activities observed suggest that antibacterials, which act by inhibiting protein synthesis, are promising candidate therapies for the treatment of pythiosis. P ythiosis is a life-threatening and chronic pyogranulomatous disease caused by the fungus-like pathogen Pythium insidiosum, the main oomycete species capable of infecting humans and other animals (1, 2). Although there have been a few reports of clinical cures of cases of pythiosis with antifungal therapy (3, 4), the data from the literature on the clinical management of pythiosis patients with treatment by antifungals indicate that such therapy has been largely ineffective (2,5,6). The genus Pythium is unable to synthesize ergosterol, the active target of most antifungals, which partly explains why this class of drugs has been ineffective (2).Studies on the in vitro susceptibility of the clinical isolates of P. insidiosum to antifungal drugs have shown divergent results, and there are no international protocols approved for evaluating the in vitro susceptibility of P. insidiosum. Interestingly, previous studies have shown that P. insidiosum is quite sensitive to antibacterials belonging to the classes of macrolides, tetracyclines, and glycylcyclines (7,8) and that its combination with antifungal drugs can result in synergistic interactions in vitro (9). However, the effects of antibacterial agents that inhibit protein synthesis on P. insidiosum have not been studied extensively. Thus, the objective of this study was to compare the in vitro susceptibilities of P. insidiosum to a number of antibacterial and antifungal drugs using the Clinical and Laboratory Standards Institute (CLSI) M38-A2 broth microdilution, CLSI M51-A disk diffusion, and Etest methods.We evaluated the susceptibility of 25 Brazilian P. insidiosum strains isolated from equine pythiosis lesions. All of the isolates were identified using a PCR-based assay according to Botton et al. (10). The reference strains included P. insidiosum CBS 101555 from an equine pythiosis case and P. insidiosum CBS 119452 and Pythium aphanidermatum CBS 128995 from human pythiosis cases.The broth microdilution (BMD) reference assay was carried out following the CLSI M38-A2 guidelines (11), as previously described (12, 13). The final concentrations of the antimicrobial agents tested in the wells ranged from 1,024 to 0.5 g/ml for mupirocin and tobramycin and from 256 to 0.125 g/ml for azithromycin, clarithromycin, clindamycin, chloramphenicol, doxycycline, erythromycin, florfenicol, fluconazole, fusidic acid, lincomycin, linezolid, minocycline, roxithromycin, terbinafine, tetracycline, tigecycline, and tilmicosin. The final conce...

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“…A extração total do DNA foi realizada de acordo com o protoloco descrito por Möller et al (1992) e modificado por Klassen et al (1996). A reação em cadeia de polimerase (PCR) das regiões ITS e cox II e o sequenciamento de DNA foram realizados conforme descrito por Azevedo et al (2012). As sequências obtidas foram analisadas utilizando-se o pacote de programas Staden e comparadas a sequências de referência de Pythium disponíveis no GenBank (http:// www.ncbi.nlm.nih.gov).…”

Section: Methodsunclassified

“…A reprodução experimental da pitiose com um isolado de P. insidiosum de origem ambiental comprova a patogenicidade dessa espécie para mamíferos, bem como confirma que os ambientes pantanosos são a fonte de infecção e mantêm o ciclo biológico do oomiceto, que utiliza plantas aquáticas para o seu desenvolvimento e reprodução formando zoósporos infectantes, conforme previamente descrito por Chaffin et al (1995), Miller (1983), Mendoza et al (1993), Supabandhu et al (2008) e Fonseca et al (2014. Adicionalmente, a relação filogenética desse isolado foi previamente estudada por Azevedo et al (2012), os quais demonstraram que isolados brasileiros de P. insidiosum oriundos de diferentes regiões do Brasil foram geneticamente similares, compartilhando o mesmo ancestral comum. Esses dados, juntamente com a capacidade de P. insidiosum ambiental de causar a pitiose em animais experimentais, evidenciam que a patogenicidade de P. insidiosum independe da origem do isolado.…”

Section: Discussão E Conclusãounclassified

Isolamento e caracterização de espécies de Pythium de ambientes aquáticos no Estado do Rio Grande do Sul e avaliação da patogenicidade em modelo experimental

et al. 2017

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RESUMO: Foram coletadas 186 amostras de água de ambientes pantanosos em 13 municípios das regiões Sul, Central e Oeste do Rio Grande do Sul, Brasil, com o objetivo de isolar e caracterizar espécies de Pythium e avaliar a sua patogenicidade empregando coelhos como modelo experimental. Em 11,8% (n=22) das águas coletadas foram isoladas diferentes espécies de Pythium incluindo: P. insidiosum (n=1), P. catenulatum (n=3), P. pachycaule voucher (n=1), P. rhizo-oryzae (n=3), P. torulosum (n=4) e Pythium spp. (n=10). Zoósporos desses micro-organismos foram produzidos in vitro e inoculados por via subcutânea em coelhos, os quais foram avaliados durante 45 dias. Dentre os oomicetos testados, apenas P. insidiosum evidenciou patogenicidade, causando pitiose no modelo experimental, evidenciando que, em nossas condições, apenas esta espécie de Pythium é patógena para mamíferos.

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Phylogenetic relationships of Brazilian isolates of Pythium insidiosum based on ITS rDNA and cytochrome oxidase II gene sequences

Cited by 31 publications

References 29 publications

In Vitro Susceptibility of Brazilian Pythium insidiosum Isolates to Essential Oils of Some Lamiaceae Family Species

In Vitro Susceptibility of Brazilian Pythium insidiosum Isolates to Essential Oils of Some Lamiaceae Family Species

New Insights into the In Vitro Susceptibility of Pythium insidiosum

Isolamento e caracterização de espécies de Pythium de ambientes aquáticos no Estado do Rio Grande do Sul e avaliação da patogenicidade em modelo experimental

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