Temperatures Outside the Optimal Range for Helicobacter pylori Increase Its Harboring within Candida Yeast Cells.

Helicobacter pylori is capable of entering into yeast, but the factors driving this endosymbiosis remain unknown. This work aimed to determine if temperatures outside the optimal range for H. pylori increase its harboring within Candida. H. pylori strains were co-cultured with Candida strains in Brucella broth supplemented with 5% fetal bovine serum and incubated at 4, 25, 37 or 40 °C. After co-culturing, yeasts containing bacteria-like bodies (Y-BLBs) were observed by optical microscopy, and the bacterium were identified as H. pylori by FISH. The H. pylori 16S rRNA gene was amplified from the total DNA of Y-BLBs. The viability of intra-yeast H. pylori cells was confirmed using a viability assay. All H. pylori strains were capable of entering into all Candida strains assayed. The higher percentages of Y-BLBs are obtained at 40 °C with any of the Candida strains. H pylori also increased its harboring within yeast in co-cultures incubated at 25 °C when compared to those incubated at 37 °C. In conclusion, although H. pylori grew significantly at 40 °C, this temperature increased its harboring within Candida. The endosymbiosis between both microorganisms is strain-dependent and permits bacterial cells to remain viable under the stressing environmental conditions assayed.

Candida albicans, a reservoir of Listeria monocytogenes?

Listeria monocytogenes is a pathogen causing serious or mortal infections in human risk populations. Its infectivity is in part due to its ability to infect diverse eukaryotic cells. Since several bacteria can enter into yeast cells, including Candida albicans, the aims of this work were to evaluate if L. monocytogenes was able to harbor, retaining its viability, within C. albicans cells and to evaluate the effect of temperature and an antibiotic as stressing factors in its rate of entry into yeast cells. Both microorganisms were co-incubated in BHI broth during 48 h and the entry of bacteria into yeast cells was evaluated at different times. Then, yeasts free of extracellular bacteria were obtained seeding samples of the co-culture on YGC agar, which contains chloramphenicol, to obtain extracellular bacteria-free yeasts. These extracellular bacteria free yeasts were used to search for bacterial DNA in total yeast DNA and to evaluate the viability of intra-yeast bacteria. Finally, the effect of temperature and of chloramphenicol as inducers of stress on the rate of bacterial entry into yeast cells were investigated. After co-culturing both microorganisms, wet mount optical microscopy showed the presence of moving bacteria within yeasts and transmission electron microscopy confirmed the presence of intra-yeast bacteria. PCR allowed to amplify L. monocytogenes iap gene in C. albicans total DNA obtained from yeasts free of extracellular bacteria. Moreover, the SYTO 9 green fluorescence observed in bacterial cells within vacuoles of yeasts suggests that intra-yeast bacteria remain viable. Furthermore, the entry of L. monocytogenes into yeasts cells was favored by the presence of stressing factors (chloramphenicol and temperature). Therefore, yeasts may be reservoirs of viable L. monocytogenes and might spread them to the following generations of yeasts.

Factors associated with the presence of helminth eggs in the soil of public areas in Concepción, Chile.

The aim of this study was to assess the association between the distance to the nearest feces, the type of substrate to be studied (feces, soil, grass), and whether a given area was licensed or not with the presence of helminth eggs in Concepción, Chile. A total of 256 samples taken from feces and either from soil or grass at 10 cm, 50 cm, and 100 cm from feces (including 16 public areas), were examined for the presence of parasites using the ZnSO4 technique. The association between variables with the presence of eggs was assessed with multifactorial logistic regressions. 24.21% of samples presented at least one egg. The higher odds of Toxocara egg presence was positively associated with the licensed 'area type' and the soil 'sample type' (when compared with feces). The odds of Ancylostomatidae egg presence was positively associated with the licensed 'area type', but negatively associated with the soil 'sample type' (compared with feces). The results suggest that finding eggs must be interpreted differently based on the parasite species and substrate to be analyzed, and that the presence of parasitized dogs is a more important contributing factor than the frequency with which the ground is cleaned of feces.

Factors associated with the presence of helminth eggs in the soil of public areas in Concepción, Chile / Fatores associados à presença de ovos de helmintos no solo de áreas públicas em Concepción, Chile

Abstract The aim of this study was to assess the association between the distance to the nearest feces, the type of substrate to be studied (feces, soil, grass), and whether a given area was licensed or not with the presence of helminth eggs in Concepción, Chile. A total of 256 samples taken from feces and either from soil or grass at 10 cm, 50 cm, and 100 cm from feces (including 16 public areas), were examined for the presence of parasites using the ZnSO4 technique. The association between variables with the presence of eggs was assessed with multifactorial logistic regressions. 24.21% of samples presented at least one egg. The higher odds of Toxocara egg presence was positively associated with the licensed 'area type' and the soil 'sample type' (when compared with feces). The odds of Ancylostomatidae egg presence was positively associated with the licensed 'area type', but negatively associated with the soil 'sample type' (compared with feces). The results suggest that finding eggs must be interpreted differently based on the parasite species and substrate to be analyzed, and that the presence of parasitized dogs is a more important contributing factor than the frequency with which the ground is cleaned of feces.

Resumo O objetivo deste estudo foi avaliar a associação da distância das fezes mais próximas, o tipo de substrato a ser estudado (fezes, solo, grama) e se as áreas foram licenciadas ou não, com a presença de ovos de helmintos zoonóticos em Concepción, Chile. Um total de 256 amostras colhidas no fecais, no solo ou na grama e a 10, 50 e 100 cm de fezes (incluindo 16 áreas públicas), foram examinadas quanto à presença de parasitas usando a técnica de flotação de sulfato de zinco. A associação de variáveis ​​com a presença de ovos foi avaliada com regressões logísticas multifatoriais. Os 24,21% das amostras apresentaram pelo menos um ovo. As chances mais altas de ovos de Toxocara foram associadas positivamente ao 'tipo de área' licenciado e ao 'tipo de amostra' do solo (em comparação com as fezes). As chances de ovos de Ancylostomatidae também foram positivamente associadas ao 'tipo de área' licenciado, mas negativamente associadas ao 'tipo de amostra' do solo (em comparação com as fezes). Os resultados sugerem que o achado de ovos deve ser interpretado de maneira diferente em relação às espécies de parasitas e ao substrato a ser analisado, e que a presença de cães parasitados parece ser mais importante do que a frequência de limpeza das fezes do solo.