We evaluated the presence of DNA of Giardia, Toxoplasma, and Cryptosporidium by PCR, and of Giardia and Cryptosporidium genera by immunofluorescence antibody test (IFAT), in water samples, before, during, and after plant treatment for drinkable water. We applied this method in 38 samples of 10 l of water taken from each of the water treatment steps and in 8 samples taken at home (only for Toxoplasma PCR) in Quindio region in Colombia. There were 8 positive samples for Cryptosporidium parvum (21 %), 4 for Cryptosporidium hominis (10.5 %), 27 for Toxoplasma gondii (58.6 %), 2 for Giardia duodenalis assemblage A (5.2 %), and 5 for G. duodenalis assemblage B (13.1 %). By IFAT, 23 % were positive for Giardia and 21 % for Cryptosporidium. An almost perfect agreement was found between IFAT and combined results of PCR, by Kappa composite proportion analysis. PCR positive samples were significantly more frequent in untreated raw water for C. parvum (p = 0.02). High mean of fecal coliforms, high pH values, and low mean of chlorine residuals were strongly correlated with PCR positivity for G. duodenalis assemblage B. High pH value was correlated with PCR positivity for C. parvum. Phylogenetic analysis of DNA sequences was possible, showing water and human clinical sequences for Toxoplasma within the same phylogenetic group for B1 repeated sequence. PCR assay is complementary to IFAT assay for monitoring of protozoa in raw and drinkable water, enabling species identification and to look for phylogenetic analysis in protozoa from human and environmental sources.

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Purpose To stablish if Blastocystis subtypes influences gastrointestinal symptoms. Methods Case-control study. We obtained sequencing for Blastocysts subtyping from 13 patients with gastrointestinal symptoms (diarrhea or abdominal pain) and 12 from individuals without symptoms. Results 12 sequences were from Subtype 2 and one from Subtype 3 in symptomatic individuals and nine samples were from Subtype 1, one from Subtype 2, and two from Subtype 3 in asymptomatic individuals. The prevalence of subtype 2 in symptomatic individuals was vastly different compared to the frequency in asymptomatic individuals (84.6% vs. 16.6%; OR 27.5 95% CI 3.2-233; Fisher exact test p = 0.0010201335). After in vitro culture, 22 isolates were obtained. Significant differences were observed for the 12 isolates from Subtype 2 that get a smaller number of total cells with dominant growth of vacuolar forms, compared with Subtypes 1 and 3, after eight days of culture. Conclusion Our results suggest that gastrointestinal symptoms in Colombian individuals with Blastocystis infection depend on the infecting subtype with peculiar phenotypic characteristics in in vitro culture.

The probiotic activity in the intestinal microbiota depends on its survival during food storage and its passage through the gastrointestinal tract. This study aimed to evaluate the effect of storage and stress conditions such as temperature, pH and bile salts on the viability of Bifidobacterium animalis microencapsulated and incorporated in plantain flour. Between days 21 and 28, the failure percentage decreased from 93% to 27%. The mean counts of B. animalis were statistically different with change of temperature, pH and bile salt concentration. For the temperature, the counts obtained at 50 °C and 80 °C decreased by 60.1% and 90.2%, respectively. Likewise, at pH 2.5 showed a over 90% survival reduction during 60 min; whilst at pH 3.5 during 60 min the survivals were less than 50%. Finally, the counts achieved using 1 g/L of bile salts were higher than those obtained at 3 and 5 g/L. The results indicate the need to evaluate other capsular components to improve the survival of B. animalis microencapsulated and incorporated in plantain flour.