Immunological, histopathological, and ultrastructural evidence of steroid-induced reactivation of chronic murine toxoplasmosis.

We developed a model of steroid-induced reactivation of chronic murine toxoplasmosis to mirror similar effects of steroids or other immunosuppressants in infected humans. Immunological, histopathological, and ultrastructural parameters were reported. Prior to steroid administration, mice were infected with 10 cysts of the Me49 strain of Toxoplasma gondii. Mice were treated with dexamethasone (DXM, 2.5 mg/kg/day in drinking water), alone or combined with Solu-Cortef (SOLU, 50 mg/kg by subcutaneous injection 3 times a week) for 7 weeks or left untreated as control. Histopathological changes and ultrastructural effects of steroids on the course of chronic toxoplasmosis were recorded. By electron microscopy, the brains of infected combined treated mice showed an increase in number of tachyzoites and bradyzoites, degeneration, and necrosis of neural cells and hydropic degeneration besides the observed rupture of toxoplasma cysts releasing free tachyzoites in brain tissue. DXM+SOLU-combined treatment also significantly increased mortality, mean brain cyst count as compared to infected untreated mice (P = .01 and). Moreover, 3/12 (25%) treated animals developed clinical signs of toxoplasmic encephalitis. This simple model of drug-induced reactivation of chronic toxoplasmosis permits investigation of host-parasite interaction and may be used for the evaluation of chemotherapeutics in immunocompromised infected patients.

In vitro activity of nitazoxanide against some metronidazole-resistant and susceptible Trichomonas vaginalis isolates.

Trichomonas vaginalis cases refractory to metronidazole (MTZ) treatment had been reported. This study aimed to the assessment of in vitro metronidazole resistance among Trichomonas positive cases with treatment failure by determination of metronidazole minimal lethal concentration (MLC), and to the evaluation of the in vitro efficacy of nitazoxanide (NTZ) as compared to metronidazole (MTZ) in both resistant and susceptible isolates. Drug testing was carried out by an aerobic tube assay where suspension of Trichomonas trophozoites was exposed for 24 and 48 h to serial dilution of metronidazole and nitazoxanide. In refractory isolates n = 30, median MLC conc. for MTZ was 100 µg/ml versus 50 µg/ml for NTZ (P < .0001). After 48 h median MLC conc. for MTZ was 25 µg/ml versus 12 µg/ml for NTZ (P < .0001). NTZ against resistant isolates was twice as active as MTZ at 24 h and increased to 2.5 times at 48 h while in susceptible isolates, NTZ was twice as active as MTZ at both 24 h and 48 h. MTZ was about 8 times more active in susceptible than in resistant isolates. So, high doses of metronidazole in resistant cases will likely increase side effects. The study proved the activity of NTZ against trichomoniasis especially in cases with MTZ resistance.

The genetic diversity of metronidazole susceptibility in Trichomonas vaginalis clinical isolates in an Egyptian population.

Trichomoniasis is the most common curable sexually transmitted disease worldwide. Resistance to metronidazole in treating trichomoniasis is a problematic health issue. We aimed to determine the minimum lethal concentration (MLC) of metronidazole for Trichomonas vaginalis isolates detected in Mansoura, Egypt and studied the genotypic profile of these isolates. Vaginal swab specimens were obtained from 320 symptomatic and 100 asymptomatic females, for whom clinical examination, vaginal discharge wet mount, Giemsa stain, and culture in modified Diamond's media were performed. Metronidazole susceptibility testing by an aerobic tube assay was performed. Both sensitive and resistant isolates were examined by PCR amplification followed by restriction fragment length polymorphism (RFLP). Trichomonas vaginalis was identified in 49/420 (11.7%) using either culture or PCR, while wet mount and Giemsa stain detected the parasite in 8.1 and 7.6% of participants, respectively. After 48 h incubation, most isolates were sensitive to metronidazole with a minimal lethal concentration (MLC) of 1 µg/ml. Mild resistance was observed in two isolates with MLCs of 64 µg\ml and mild to moderate resistance was observed in an additional two isolates with MLCs of 128 µg/ml. The four isolates that demonstrated low to moderate metronidazole resistance displayed a unique genotype band pattern by RFLP compared to the other 45 samples that were metronidazole sensitive. Our results highlight the presence of in vitro metronidazole tolerance in a few T. vaginalis isolates in Mansoura, Egypt that may lead to the development of drug resistance as well as the possibility of an identifying RFLP pattern in the isolates.

Association Between Giardia Genotype and Oxidative Stress Biomarkers Among Giardia-Infected Children: A Case-Control Study.

PURPOSE: Giardia duodenalis is the most common worldwide intestinal protozoal infection. The implication of free radicals in organ injury occurs through oxidative stress. Infections as Giardia may act as a triggering or promoting factor for oxidative stress, particularly in children with compromised immunity. Besides, the effect of Giardia genotype on oxidative stress status is yet to be explored. Therefore, we sought to compare the oxidative stress status between Giardia positive cases (case group) and Giardia negative cases (control group), and to explore the association between Giardia genotype and the level of oxidative stress markers in Giardia-infected children, especially those receiving immunosuppressive therapy. METHODS: Pediatric patients attending Mansoura University Children Hospital in the period from April 2015 to October 2016 were enrolled. Both case (n = 50) and control (n = 50) groups were further subdivided into immunosuppressive therapy recipients (ITR) and non-immunosuppressive therapy recipients (NITR). Genotyping of Giardia from positive stool samples by PCR was carried out, and oxidative stress markers were measured from venous blood samples. RESULTS: Giardia positive cases had higher levels of Malondialdehyde (MDA) and lower levels of total antioxidant capacity (TAC). MDA highest level was associated with mixed genotypes A and B, while the highest TAC level was associated with Giardia genotype A in both ITR and NITR cases. CONCLUSION: Elevated oxidative stress biomarkers in pediatric patients infected with specific Giardia genotypes should receive considerable attention, because if prompt treatment is not conducted, oxidative damage may occur in patients with giardiasis, especially those receiving immunosuppressive therapy.

Seroprevalence and Genetic Characterization of Toxoplasma gondii among Children with Neurodevelopmental Disorders in Egypt.

Toxoplasma gondii is a parasite with a special predilection for the central nervous system. Toxoplasmosis's contribution to the triggering of many neurodevelopmental disorders was established. This study aimed to detect the seroprevalence and genotypes of T. gondii strains in children with neurodevelopmental disorders. The study included 180 children with neurodevelopmental disorders and 180 children in the control group. Assessment of seropositivity of Toxoplasma IgM and IgG antibodies in patients and controls was carried out. Genetic characterization of T. gondii was obtained by nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) technique targeting dense granule gene (GRA6). Our results showed that the overall seroprevalence of T. gondii antibodies in the patient and controls was 35.6% and 11.7%, respectively. Nested PCR showed positivity in 11.1% of the patient group for T. gondii DNA. T. gondii seropositivity rate was significantly high in patients with hydrocephalus and also in patients with epilepsy. Positive nested PCR was significantly high in children with hydrocephalus only. Genotyping using nested PCR-RFLP showed genotype I (80%) followed by atypical strains (20%) with no association with any specific clinical presentation. In conclusion, among toxoplasmosis-positive children with neurodevelopmental disorders, analysis of T. gondii GRA6 locus revealed the predominance of type I genotype followed by atypical strains.

Blastocystis hominis among symptomatic and asymptomatic individuals in Talkha Center, Dakahlia Governorate, Egypt.

Blastocystis hominis is now getting acceptance as an agent of human intestinal disease. B. hominis in stool samples of symptomatic and asymptomatic individuals was evaluated as a possible cause of gastro-intestinal troubles. B. hominis was found in 106 (10.1%) out of 1050 individuals examined from six villages and one city in Talkha Center, Dakahlia Governorate. The highest infection rate was in Manshayt El-Badawy village (25.47%), whereas Talkha City showed the lowest rate (4.73%). Age group 10-20 years had higher infection (13.3%). In twenty-three symptomatic patients, B. hominis represented the only causative parasitic agent. The most common symptoms were diarrhoea (30.4%), abdominal pain (26.1%), flatulence (21.7%). vomiting (13.1%) and fatigue (8.7%). High concentrations of B. hominis were found in symptomatic patients than in asymptomatic ones with statistical significant difference (8.2 cells/100 x field versus 3.8 respectively). The mean number of B. hominis was significantly high in patients complaining of diarrhoea and abdominal pain.

Geoparasites in rural Dakahlia Governorate, a preliminary based study for development of the community-based intervention programs.

A prospective study was carried out to detect the rural prevalence and intensity of geoparasites in Dakahlia Governorate, Egypt. A total of 1070 soil samples were collected; 571 (53.4%) were infected with one or more parasites. Only 24% of samples were infected with one parasite, 16.4% and 13% with two, and more than two parasites respectively, and the difference was statistically significant. The geoparasites in a descending order of their prevalence were: E. histolytica cysts (9.2%), Toxocara eggs (9.1%), Giardia cysts (7.9%), Cryptosporidium oocysts (6.1%), Trichostrongylus eggs and larvae (5.6%), Isospora oocysts (4.3%), Acanathamoeba cysts (4.1%), Naegleria cysts (3.6%), Dust mites (2.7%), H. diminuta eggs (2.7%), Strongyloides free living adults, rhabditiform and filariform larvae (2.3%), H. nana eggs (1.7%), S. mansoni eggs (1.2%), Ascaris eggs (0.6%), Ancylostoma larvae (0.5%), Taenia eggs (0.4%), Trichocephalus eggs (0.4%) and F. gigantica eggs (0.2%). The prevalence of parasitic infections was significantly higher (P<0.001) in fields (63.4%) than streets (47.7%) and indoor-yards samples (35.3%). The intensity of infections was significantly higher (P< 0.001) in streets than fields and indoor-yards (18.1, 9.7 & 1 parasite/10 gm of soil respectively).

Some molecular aspects in schistosomiasis mansoni and toxoplasmosis.

The IL-2 and IL-4 cytokines production represent cellular Th1 & Th2 immune responses respectively were associated with chronic schistosomiasis mansoni (stages 1-4) and chronic toxoplasmosis gondii. In the hepatosplenic schistosomiasis, the level of IL-2 and disease stage increased in parallel (P<0.05, <0.01, <0.01 & <0.001 in stages 1, 2, 3 & 4 respectively), whereas, IL-4 was highly significantly increased in stage 1 than control (P<0.001), then decreased to lower levels. The mean concentrations of IL-2 & IL-4 in patients with T. gondii were higher compared to control being more marked in IL-2 (P<0.001) versus IL-4 (P< 0.01). The data indicated that there are patterns of cytokine expression characteristic of type 1 & type 2 responses in vivo, with the ultimate goal of being able to manipulate the response to minimize inflammation and fibrosis for clinical benefit.