Pathological studies of different genotypes of human cryptosporidium Egyptian isolates in experimentally mice

The genotyping of cryptosporidium clinical isolates obtained from 36 gastrointestinal symptomatic patients were identified by nested PCR for amplification of 18S rRNA followed by RFLP analysis using Ssp1 and Vsp1, and then pathological changes between different cryptosporidium genotypes were evaluated in experimentally infected mice. Cryptosporidium genotypes [C. parvum, C. hominis and C. melegridies] were detected [66.7%, 27.7% and 5.6%] respectively in human isolates. Different degrees of pathological changes were found among infected mice by different Cryptosporidium genotypes. Moderate and severe degrees of pathological changes with infection score ranging from 2 to 4 were found in all infected mice with C. parvum [except one isolate], while mild degree of pathological changes with infection score of 2 was found in all mice with C. melegridies. The results showed statistically significant relation between genotype and pathological degrees. There were no differences in the average number of oocysts per smear in Group II and Group III while in Group I, there was no oocysts shedding

Evaluation of polymerase chain reaction on amniotic fluid for diagnosis of congenital toxoplasmosis

The present study assessed sensitivity and specificity of PCR targeting P30 gene in diagnosis of congenital toxoplasmosis using amniotic fluid samples. A total of 358 pregnant women in their first trimester of pregnancy, most of them were asymptomatic while the others suffered lymphadenopathy, fever and/or malaise. The serum sample from each woman was screened for Toxoplasma-specific ELISA IgM and IgG. Sero-negative females were then screened in 2[nd] and 3[rd] trimesters for sero-conversion. Amniocentesis was performed to seropositive and sero-converted women. Detection of Toxoplasma DNA in AF was done by animal inoculation and PCR targeting P30 gene. 85/358 women were sero-positive for Toxoplasma. Congenital infection was detected in 14/85 fetuses by MI. One mouse had tachyzoite in peritoneal exudate while other 13 showed cysts in histpathological sections of mice. PCR test targeting P30 gene was positive in 13 with additional four fetuses, only PCR gave positive results, and serologic follow-up of suspected fetuses [17] by IgM ELISA confirmed congenital toxoplasmosis. Sixteen cases of congenitally infected newborn were a symptomatic. One was clinically diagnosed [ventricular dilatation] by the ultrasound. The PCR drastically changed the diagnostic repertoire for prenatal diagnosis. The sensitivity and specificity of PCR targeting P30 gene on AF samples were 92.9% and 94.4% respectively while positive predictive value [PPV] was 76.5%, and negative predictive value [NPV] was 98.5%. Its disadvantages were in fact that negative result cannot exclude acute infection, and thus must be confirmed by MI and it is also an expensive technique

Identification of blastocystis hominis in patients with irritable bowel syndrome using microscopy and culture compared to PCR

There is much controversy regarding the pathogenicity of B. hominis especially in patients with irritable bowel syndrome. Detection of B. hominis in patients with irritable bowel syndrome using different diagnostic methods; microscopy, culture and PCR. The second objective is to compare between microscopy and culture using PCR as Gold Standard. Stool samples from 83 patients with irritable bowel syndrome were subjected to microscopic examination, culture on egg diphasic medium and PCR amplification using primers based on small subunit ribosomal DNA, for diagnosis of B. hominis infection. Results: Out of 83 samples, 25 [30.1%] were found positive for B. hominis by microscopy, 34 [41%] culture and 37 [44.6%] using PCR. The sensitivity of microscopy and culture versus PCR was 62.2% d 89.2%, respectively. The specificity of microscopy and culture versus PCR was 95.7% and 97.8%, respectively. The diagnostic accuracy for microscopy and culture was 83.1% and 94% respectively. Culture proved to be a more sensitive and specific tool for detection of B. hominis than microscopy