Could PLATELIA Toxo IgM be the new gold standard for the serological diagnosis of congenital toxoplasmosis: a French multicenter study.

To assess the performance of PLATELIA Toxo IgM (Bio-Rad) and Toxo ISAGA (BioMérieux) to detect anti-Toxoplasma IgM in infants at risk of congenital toxoplasmosis, a retrospective multicenter study was conducted comparing serological results obtained in the framework of routine diagnosis work-up for congenital toxoplasmosis. All infants born to mothers infected with T. gondii during pregnancy from 2010 to 2020 with at least 6 months of serological follow-up were included (n = 1,010). One thousand ten cases were included, of which 250 infants (24.75%) had congenital toxoplasmosis. A total of 1039 sera were included. The concordance between the two techniques was 96%, with kappa coefficient of 0.87, showing an almost perfect agreement between ISAGA and PLATELIA. Cumulative sensitivity and specificity were 73.2% and 99.5.% and 74.8% and 100% for ISAGA and PLATELIA, respectively. The mean time to detect IgM using ISAGA and PLATELIA tests was 6.9 ± 20.1 days and 5.6 ± 14.7 days, respectively not significant (ns). Finally, the sensitivity of ISAGA and PLATELIA to detect IgM antibodies in infected neonates at 5 days of life was 62% and 64%, respectively. Performances of PLATELIA Toxo IgM assay were comparable to the gold standard ISAGA. This enzyme-linked immunosorbent assay is suitable for routine serology for the diagnosis of congenital toxoplasmosis in newborns. IMPORTANCE This study will help clinical microbiologists to chose an alternative serological method for the neonatal diagnosis of congenital toxoplasmosis, once the gold standard technique ISAGA will be withdrawn next year.

PCR and culture for diagnosis of Acanthamoeba keratitis.

BACKGROUND/AIMS: Acanthamoeba keratitis (AK) is a rare but sight-threatening infection. Molecular diagnosis of corneal scraping has improved the diagnosis of AK. Different molecular targets and conditions have been used in diagnosis thus far. In this study, we prospectively compared the performance of five PCR assays on corneal samples for the diagnosis of AK. METHODS: 1217 corneal scraping samples were obtained from patients, for whom an AK was suspected. Sample processing involved both molecular diagnostics and culture. Acanthamoeba PCR assays detected different regions of the Acanthamoeba nuclear small-subunit rRNA gene: three final point PCR assays using Nelson, ACARNA and JDP1-JDP2 pairs of primers, and two real-time PCR assays using Acant primer-probe. Human DNA and internal control were co-amplified in the real-time PCR assay to ensure scraping quality and the absence of inhibitors. In the absence of a gold standard, the performance of each test was evaluated using latent class analysis. Genotypes of Acanthamoeba isolates were also characterised. RESULTS: Estimated prevalence of AK was 1.32%. The sensitivity of Acanthamoeba diagnostic PCRs (73.3% to 86.7%) did not differ significantly from that of culture (66.7%), or according to the target sequence or the technology. Sensitivity could be increased to 93.8% or 100% by combining two or three assays, respectively. PCR specificity (99.3% to 100%) differed between the assays. T4 was the predominant Acanthamoeba genotype (84.6%). CONCLUSIONS: Culture and a single PCR assay could lead to misdiagnosing AK. A combination of different PCR assays and improved sample quality could increase diagnosis sensitivity.

A cluster of three cases of trichinellosis linked to bear meat consumption in the Arctic.

We report here three cases of trichinellosis due to polar bear meat consumption in East Greenland. In the past 20 years, 31 cases of trichinellosis have been reported in French travellers to the Arctic (North Quebec, Nunavut and Greenland) who consumed undercooked meat from black, brown, or polar bears. If local communities are increasingly becoming aware of the risk of trichinellosis, travellers visiting regions where bear meat is consumed should be informed of the risk of eating raw or non-heat-processed meats.

[Angiostrongylosis or eosinophilic meningitis]. / Angiostrongyloïdose ou méningite à éosinophiles.

Eosinophilic meningitis, or angiostrongyliasis, is a common disease in Asia, in the Caribbean and in the Pacific islands. It is caused by a rat lungworm Angiostrongylus cantonensis. Infection occurs by consumption of raw or undercooked snails. Diagnosis is based on epidemiological criteria, clinical manifestations, elevated count of eosinophils in the cerebrospinal fluid and serological tests. Treatment is symptomatic and supportive.