Genomic Analysis of Limosilactobacillus fermentum ATCC 23271, a Potential Probiotic Strain with Anti-Candida Activity.

Limosilactobacillus fermentum (ATCC 23271) was originally isolated from the human intestine and has displayed antimicrobial activity, primarily against Candida species. Complete genome sequencing and comparative analyses were performed to elucidate the genetic basis underlying its probiotic potential. The ATCC 23271 genome was found to contain 2,193,335 bp, with 2123 protein-coding sequences. Phylogenetic analysis revealed that the ATCC 23271 strain shares 941 gene clusters with six other probiotic strains of L. fermentum. Putative genes known to confer probiotic properties have been identified in the genome, including genes related to adhesion, tolerance to acidic pH and bile salts, tolerance to oxidative stress, and metabolism and transport of sugars and other compounds. A search for bacteriocin genes revealed a sequence 48% similar to that of enterolysin A, a protein from Enterococcus faecalis. However, in vitro assays confirmed that the strain has inhibitory activity on the growth of Candida species and also interferes with their adhesion to HeLa cells. In silico analyses demonstrated a high probability of the protein with antimicrobial activity. Our data reveal the genome features of L. fermentum ATCC 23271, which may provide insight into its future use given the functional benefits, especially against Candida infections.

A Study of the Disruptive Effect of the Acetate Fraction of Punica granatum Extract on Cryptococcus Biofilms.

Cryptococcosis, caused by yeasts of the genus Cryptococcus, is an infectious disease with a worldwide distribution. Cryptococcus neoformans and Cryptococcus gattii are the species that commonly cause this disease in humans; however, infections caused by Cryptococcus laurentii, especially in immunocompromised patients, are increasingly being reported. Owing to the increase in the resistance of fungi to antifungals, and a lack of treatment options, it is important to seek new therapeutic alternatives such as natural products. Among these are plant species such as Punica granatum, which is used in folk medicine to treat various diseases. This study aimed to evaluate the activity of the acetate fraction of P. granatum leaf extract against environmental and clinical isolates of Cryptococcus. Three environmental isolates of C. laurentii, PMN, PMA, and PJL II, isolated from soils of different municipalities in the state of Maranhão, a clinical isolate, C. gattii, from a patient with neurocryptococcosis, and a standard strain of C. gattii (ATCC 32068) were used. The minimum and fractional inhibitory concentrations (MIC and FIC, respectively) and time-kill curve of the extract and fluconazole were determined to assess the susceptibility profile of the fungal isolates. Larvae of Tenebrio molitor were infected with Cryptococcus strains, and the effects of acetate fraction of P. granatum extract and fluconazole on the survival and fungal burden were determined. The extract activity was tested against pre-formed biofilms. The acetate fraction of P. granatum extract showed promising antifungal activity against all the species of Cryptococcus evaluated in this study, with an MIC value lower than that of fluconazole. The indices obtained in the FIC test indicated that the antimicrobial effect of the combination of the extract and antifungal was indifferent for 80% of the isolates. The P. granatum acetate fraction reduced the pre-formed biofilm of some isolates, showing better activity than fluconazole, which is consistent with results from fluorescence microscopy. This is the first study on the use of P. granatum and its ability to inhibit Cryptococcus biofilms; therefore, further studies and tests are needed to investigate the components and mechanism of action of P. granatum against cryptococcosis agents.

Pathogenic potential of environmental resident fungi from ornithogenic soils of Antarctica.

We assessed the diversity of cultivable fungi in the ornithogenic soil nests of bird species like Phalacrocorax atriceps, Macronectes giganteus, Pygoscelis antarcticus, and Pygoscelis papua in the Antarctic islands. From 481 fungi isolated at 15 °C, only 50 displayed growth at 37 °C, and were identified as 14 species of 15 genera. Aspergillus fumigatus, Penicillium chrysogenum, and Rhodotorula mucilaginosa were the most abundant species obtained. Fifty taxa grew at 40 °C; displayed haemolytic and phospholipase activities; produced tiny spores, capsule, and melanin; showed growth at different pH; and showed resistance to amphotericin B. Interestingly, the minimum inhibitory concentration of amphotericin B increased by 5-10 fold for some A. fumigatus isolates after phagocytosis by amoeba. Our results show relations among fungal community compositions present in Antarctic ornithogenic soil and their pathogenic risk to humans in vitro. As the Antarctica Peninsula is a major region of the planet affected by global climate changes, our results, though preliminary, raise concerns about the dispersal of potential pathogenic microbes present in Antarctic substrates by wild birds, which can fly great distances and spread potential pathogens mainly to South America and Oceania.