The genotyping of Blastocystis hominis clinical isolates obtained from 28 gastrointestinal symptomatic patients and 16 asymptomatic individuals were identified by polymerase chain reaction using sequenced-tagged site (STS) primers. Then, pathophysiological variability between different B. hominis genotypes was evaluated in experimentally infected rats. Only four B. hominis subtypes (1, 2, 3, and 4) were detected (18.2%, 9.1%, 54.5%, and 18.2%, respectively) in human isolates. In symptomatic isolates, subtypes 1, 3, and 4 were detected in 8 (28.6%), 16 (57.1%), and 4 (14.3%) patients, respectively. In asymptomatic isolates, subtypes 2, 3, and 4 were identified in 4 (25%), 8 (50%), and 4 (25%), respectively. Subtype 3 was the commonest in humans. Different degrees of pathological changes were found among infected rats by symptomatic subtypes compared with asymptomatic subtypes. The moderate and severe degrees of pathological changes were found only in symptomatic subtypes infected rats while mild degree was found only in asymptomatic subtypes infected rats. Only subtype 1 induced mortality rate with 25% among infected rats. On evaluation of the intestinal cell permeability in the Ussing chamber, a prominent increase in short circuit current (DeltaIsc) was found in symptomatic subtype 1 compared to symptomatic subtypes 3 and 4 infected rats. Minimal effects were found in the asymptomatic and control groups. The results proved that subtype 1 was clinically and statistically highly relevant to the pathogenicity of B. hominis while subtype 2 was irrelevant. Also, the results suggest the presence of pathogenic and nonpathogenic strains among subtypes 3 and 4.

Dientamoeba fragilis is a parasite that has been recognized as a causative agent of gastrointestinal symptoms. The search for genetic variation in D. fragilis based on the small-subunit (SSU) rRNA gene using restriction fragment length polymorphism was found not useful for molecular epidemiology. In this study, genetic variability of different clinical isolates of D. fragilis was explored by high-resolution melting curve (HRM) following polymerase chain reaction (PCR) in a one-step closed-tube method. Thirty fecal samples from irritable bowel syndrome (IBS) patients having D. fragilis trophozoites and negative for other organisms were involved in this study. According to the type of diarrhea, eight patients had acute, 14 patients had chronic intermittent, and eight patients had diarrhea alternating with constipation. HRM proved that four profiles (subtypes) were present as detecting by scanning mutation. One of these profiles (profile 1) was predominant (50%). Profile 2 was present on 20%. Profiles 3 and 4 were present on 16.7% and 13.4%, respectively. No mixed profiles were detected among the samples. The melting curves characterized by T(m)1=77.17+/-0.29 degrees C in profile 1, T(m)1=77.37+/-1.45 degrees C in profile 2, T(m)1=74.24+/-0.08 degrees C and T(m)2=79.64+/-0.09 degrees C in profile 3, and T(m)1=75.51 +/- 0.09 degrees C and T(m)=79.42 +/- 0.09 degrees C in profile 4. The relation between these profiles and types of diarrhea proved that the majority of patients having profile 1 (73.4%) and profile 4 (75%) had chronic intermittent diarrhea. All of the patients having profile 2 had acute diarrhea while all of the patients having profile 3 had diarrhea alternating with constipation. Although profile 1 was detected among all types of diarrhea, it was corresponding to 11/14 of patients with chronic intermittent diarrhea. All the differences were clinically and statistically significant. In conclusion, HRM following PCR was proved as a wide variation on D. fragilis genotypes that could be related to the characters of diarrhea among IBS patients. As the differences in HRM reflect different sequences of SSU RNA gene, thus, another study for identifying the sequences of these isolates (profiles) will be done and published later.

No abstract

Intestinal parasites and nutritional deficiency can coexist and influence each other. This study aimed to clarify the association between Giardia genotypes and presence of iron deficiency anaemia (IDA) among pre-school Egyptian children. Two groups (IDA and non-anaemic) of giardiasis children (44/group) were selected according to their recovery response after treatment of giardiasis. Each group included 24 and 20 gastrointestinal symptomatic and asymptomatic, respectively. Giardia human genotypes were performed by intergenic spacer (IGS) gene based polymerase chain reaction (PCR) with high-resolution melting curve (HRM). PCR/HRM proved that Tms of assemblage A and B ranged from 79.31 ± 0.29 to 84.77 ± 0.31. In IDA patients, assemblages A and B were found among 40/44 (90.9 %) and 4/44 (9.1 %), respectively, while in non-anaemic patients, assemblages A and B were found in 10/44 (22.7 %) and 32/44 (72.7 %), respectively, beside two (4.6 %) cases had mixed infection. The difference was statistically significant. No significant relation was found between symptomatic or asymptomatic assemblages and IDA as assemblage A was found in 21/24 (87.5 %) and 19/20 (95 %) of symptomatic and asymptomatic, respectively, while 3/24 (12.5 %) and 1/20 (5 %) of assemblage B were symptomatic was asymptomatic, respectively. A significant relation was found between assemblage A subtypes distribution among IDA patients as AI and AII were detected on 23 (52.3 %) and 16 (36.4 %) of patients, respectively, while one case (2.3 %) had mixed infection. In conclusion, assemblage A is predominant among IDA giardiasis children suggesting its role in enhancing the occurrence of IDA while B has a protective role.

The efficiency of the transmission of Giardia lamblia is assured by the presence of a cyst wall, which provides resistance to drastic osmotic and pH variations. Both magnesium oxide (MgO) nanoparticles (NPs) and microwaves (MVs) are known to inactivate many microorganisms.This study compared the effects of MgO NPs & MVs irradiation on Giardia lamblia cysts in experimental mice as to treated and un-treated cysts viability, excystation, ultrastructure changes and infectivity.The results showed that the G. lamblia cysts count were reduced to (LD 90 ) after 8, 16, & 24hrs of exposure to doses 100, 50, & 25mg/ml, respectively, while reduction rate of (EC 50 ) after 8, 16, &24 hrs of exposure to dose 50, 25, & 12.5mg/ml, respectively. MVs LD 90 efficacy on cysts was detected after 30 seconds while EC 50 after 20 seconds. Failure of excystation was 90% and 98% among MgO NPs and MVs treated cysts. MgO NPs treated cysts showed multiple cytoplasmic vesicular vacuoles while the cyst wall appeared destructive with the release of the cytoplasm outside. MVs treated cysts were filled with one big vesicular vacuole with an increase in size while some contents were decreased in size and others disappeared completely. The infectivity rate among mice inoculated with MgO NPs and microwave treated cysts was 33.3% & 8.2 % with a mild histopathological changes, with significant differences.

Purpose The relationship between the genetic diversity of Blastocystis and immune surveillance in precancerous colons with blastocystosis is still under investigation. This study aimed to identify the genetic Blastocystis variants among 54 symptomatic human isolates and their relationship to mucosal immune surveillance in the precancerous polyps of experimentally infected rats. Methods Polymerase chain reaction and high-resolution melting (PCR/HRM) curves discriminated human symptomatic Blastocystis isolates into subtypes (STs)/intrasubtypes, which were orally administered to rats to induce experimental infection. Then, the mucosal immune responses of the infected colons were evaluated in relation to polyp formation through immunostaining to identify mucus MUC2 and determine mucosal immune cell (goblet, lymphocyte and mast) counts, secretory IgA levels and parasitic intestinal invasion. Results ST1, ST3, and ST4 were found in 18.5% (10/54), 54.7% (29/54), and 27.8% (15/54) of the samples, respectively. Then, the HRM curve discriminated ST3 into the wild, mutant, and heterozygous [17/54 (31.5%), 5/54 (9.3%), and 7/54 (12.9%)] intrasubtypes. ST1 and ST4 had no genetic variations. Precancerous polyps were detected in the colons of 40.5% of the infected rats. ST1 constituted 14.7% of these cases, while the wild, mutant, and heterozygous intrasubtypes of ST3 showed polyps in 12.9%, 5.5%, and 5.5% of cases, respectively. Only 1.9% of the polyps were related to ST4. MUC2 showed weak immunostaining in 44.5% of the infected colons, and 38.9% were polyp inducers. Low goblet cell numbers and high interepithelial lymphocyte counts were significantly associated with polyp formation, particularly with ST1 and wild ST3. Among the polyp inducers, high numbers of mast cells were detected in wild ST3 and ST4, while a low number was found with heterozygous ST3. The level of secretory IgA was low in polyp-inducing STs. Most of the results were statistically significant. Conclusion Immunosurveillance showed a potential relationship between ST1 and the ST3 intrasubtypes and precancerous polyps. This relationship may provide insight into the prevention and/or development of new immunotherapeutic strategies to combat colorectal cancer.