A New IgG Immunoblot Kit for Diagnosis of Toxoplasmosis in Pregnant Women

The determination of the accurate immune status of pregnant women is crucial in order to prevent congenital toxoplasmosis. Equivocal results with conventional serological techniques are not uncommon when IgG titers are close to the cut-off value of the test, so that a confirmatory technique is needed. For this purpose, we developed a homemade immunoblot (IB) using soluble extract of Toxoplasma gondii tachyzoites and assessed it by testing 154 positive, 100 negative, and 123 equivocal sera obtained from pregnant women. In order to select the more valuable bands in terms of sensitivity and specificity, we used the Youden Index (YI). The highest YIs were those given by the 32, 36, 98, 21, and 33 bands. The simultaneous presence on the same blot of at least 3 bands showed a much higher YI (0.964) and was adapted as the positivity criterion. The analysis of results showed that our homemade IB correlated well with the commercial LDBIO Toxo II IgG(R) kit recently recommended as a confirmatory test (96.7% of concordance).

Etiology of acute diarrhea in tunisian children with emphasis on diarrheagenic escherichia coli: prevalence and identification of E.coli virulence markers

Diarrheal diseases can be caused by viral, bacterial and parasitic infections. This paper provides a preliminary image of diarrhea with regards to etiology and epidemiologic factors in Tunisian children less than five years of age. Overall, 124 diarrhoeal stools were collected from patients suffering from acute diarrhea and 54 stool samples from healthy children. All stools were examined for the presence of enteric pathogens. In diarrheagenic children, 107 pathogenic bacteria were isolated [12 Salmonella spp. [9.7%] and 95 diarrheagenic Escherichia coli strains [76.6%]: 29 enteroaggregative E.coli [EAEC] [23.4%], 15 enteroinvasive E.coli [EIEC] [12.1%], 17 enteropathogenic E.coli [EPEC] [13.7%], 26 enterotoxigenic E.coli [ETEC] [21%] and 2 enterohemoragic E.coli [EHEC] [1.6%]. However, in the control group, 23 pathogenic E.coli strains were isolated [42.6%] 8 EAEC [14.8%], 12 EIEC [22.2%] and 3 EPEC [5.5%]. Among diarrheagenic E.coli [DEC], only ETEC strains were significantly recovered from diarrheagenic children than from healthy controls [P < 0.0003]. Group A rotavirus was identified in 33.9% [n=42] of diarrheagenic children and in 11.1% among the control group [n=6]. Concerning norovirus, 8.9% [n=11] of the samples collected from diarrheagenic children and 9.2% [n=5] from the control group were positive. The prevalence of rotaviruses and Salmonella spp were also significantly higher in patients with diarrhea than in controls [P = 0.002 and P < 0.019, respectively]. Finally, enteropathogenic parasites [Entamoeba coli and cryptosporidium Oocystes] were isolated from 4.8% and 9.2% of diarrheagenic and control children, respectively. These results provide baseline data about the relative importance of different enteropathogens in Tunisian children

IgG Western Blot for Confirmatory Diagnosis of Equivocal Cases of Toxoplasmosis by EIA-IgG and Fluorescent Antibody Test

The performance values of available techniques used in serodiagnosis of toxoplasmosis are satisfactory but they raise problems of equivocal and discordant results for very low IgG titers. Recently marketed, LDBio-Toxo II IgG Western blot (IB) showed an excellent correlation with the dye test. We estimated the proportion of equivocal and discordant results between the enzyme immunoassay Platelia Toxo IgG (EIA-IgG) and fluorescent antibody test (FAT) and assessed the usefulness of the IB as a confirmatory test. Out of 2,136 sera collected from pregnant women, 1,644 (77.0%) tested unequivocally positive and 407 (19.0%) were negative in both EIA-IgG and FAT. The remaining 85 (4%) sera showed equivocal or discordant results. Among them, 73 (85.9%) were positive and 12 (14.1%) were negative in IB. Forty-one (89.1%) equivocal sera in EIA-IgG and 46 (86.8%) equivocal sera in FAT were positive in IB. Reducing the cut-off values of both screening techniques improved significantly their sensitivity in detecting very low IgG titers at the expense of their specificity. In conclusion, equivocal results in routine-used techniques and their discordance in determination of the immune status in pregnancy women were not uncommon. IB test appeard to be highly useful in these situations as a confirmatory technique.

[Acanthamoeba keratitis: report of 3 cases diagnosed in central Tunisia]

Amoeba of the genus Acanthamoeba are ubiquitous free-living protozoa encountered in water and soil. They frequently cause sight-threatening keratitis. Report of the three first cases diagnosed at the laboratory of Parasitology of Sousse Hospital. [Tunisia]. Our study concerned three lens-wearing female patients. aged 17, 20 and 29 years respectively. The patients originate from central Tunisia and presented with unilateral [2 cases] or bilateral [one case] keratitis. Diagnosis was made by demonstrating Acanthamoeba trophozoites and/or cysts on direct examination and/or culture [in agar-Escherichia coli medium] of contact lenses and/or lenses' solution. Direct examination of corneal swabs was negative in three cases but culture was positive in one. The three patients were treated with hexamidine and neomycine eye-drops for three months. Treatment led to scarring of lesions with however sequellar opacities that was minor to moderate in two cases and consisted of a central leucoma with a poor visual outcome in the last case. The need for systematic research of amoeba in lenses wearing patients with keratitis is emphasized

[Norwegian scabies, a rare diagnosis in Tunisia]

Norwegian scabies is a particular form of scabies, rarely reported in Tunisia. It habitually occurs in immunocompromised hosts, with prolounged immunosuppressive therapy, congenital immune disease, HIV-1 infection or neoplasm. We report an observation of norwegian scabies, occuring in a woman with prolounged systemic corticosteroid therapy

Observation: a 65-year old woman, with a long history of obstructive bronchoneumopathy and bronchiectasis, treated with systemic corticosteroids for 5 years, was referred with a mild pruriginous and scaly erythroderma. This dermatosis developed within 5 months, with fever and impairing of heal-th. Skin parasitological exams showed a massive infestation by sarcoptes. Histologic findings revealed multiple sarcoptes scabiei and eggs in the stratum corneum. The patient was treated with benzyl benzoate during 48 hours. She died rapid-ly with acute respiratory distress

Discussion: basing on this observation of norwegian scabies occuring in an old immunocompromised woman, we put the accent on this particular form of scabies, often misappreciated, and incite to practice skin and nail parasitological exams in case of mild pruriginous, chronic scaly erythroderma, developing in immunocompromised patients