Macrobrachium amazonicum oriundos de ambiente natural e de cativeiro: determinação da microbiota por leveduras, sensibilidade antifúngica e fatores de virulência. / Macrobrachium amazonicum coming from the wild and in captivity: determination of the microflora by yeasts, antifungal susceptibility and virulence factors.

Manoel Paiva de Araújo Neto

Macrobrachium amazonicum is the most interesting native species of prawn for Brazilian producers. Until now, reports on fungal microbiota of M. amazonicum is very scarce. This study aimed at investigating yeast microbiota of M. amazonicum and identifying fungi present in water from captivity. Additionally, we sought to establish in vitro antifungal susceptibility profile and evaluate the production of phospholipase and protease of Candida spp. isolates. For such, we used prawns from captivity from the larval to adult stage, wild prawns and samples of cultivation water. The prawns samples were macerated and suspended in sterile saline solution and the supernatant was seeded on plates containing Sabouraud agar with chloramphenicol and birdseed (Guizotia abyssinica) agar. The species identification was based on micromorphological and biochemical characteristics. Twenty-four Candida spp. isolates were submitted to antifungal susceptibility test, against amphotericin B, caspofungin, itraconazole and fluconazole, according to the methodology standardized by the Clinical Laboratory Standards Institute (document M27-A2). Additionally, these isolates were tested for phospholipase production, on egg yolk agar, and protease activity. The data were analysed by Fishers exact test, Pearsons correlation coefficient and Students T-test, with a significant level of 5% (P <0.05). Twenty-six yeast isolates were obtained from prawns and cultivation water, belonging to seven species, with C. famata (38.5%) as the most prevalent, followed by C. parapsilosis and C. guilliermondii (15.14%). Moreover, 28 isolates of filamentous fungi were found in cultivation water, belonging to five genera, with Penicillium (46.42%) as the most prevalent genus. All Candida spp. strains were sensitive to amphotericin B (MIC = 0.03125 to 0.5 μg / mL) and caspofungin (MIC = 0.03125 to 1 μg / mL). For fluconazole and itraconazole the MICs were 0.03125 to ≥ 16 μg/mL and 0.5 to ≥ 64 μg/mL, respectively. Out of all isolates tested, 33.33% were resistant to azole derivatives, two isolates of C. famata, one C. tropicalis, one C. parapsilosis, one C. guilliermondii and three C. albicans. Out of Candida spp. strains, 12.5% and 37.5% , respectively, produce phospholipase and protease. Finally, this work represents the first study on yeast microbiota of M. amazonicum, comparing wild and captive populations. Additionally, M. amazonicum can be posted as a sentinel animal for the detection of yeasts resistant to antifungal agents in the natural environment.

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