Simona Peruzzi

Evaluation of a real-time polymerase chain reaction assay for the laboratory diagnosis of giardiasis.

A real-time polymerase chain reaction (PCR) assay was evaluated in comparison with the combination of conventional methods (microscopic examination and antigen detection assay) during the period 2006 to 2008 on 771 fecal samples belonging to 386 patients to assess its usefulness for an accurate laboratory diagnosis of giardiasis. The real-time PCR assay detected Giardia intestinalis DNA in 195 samples (106 patients), including 26 samples (21 patients) negative by the conventional assays. Among the 21 patients, in 8 cases, giardiasis was previously diagnosed also by conventional methods in additional samples of the same patients, whereas in 13, it would have been undiagnosed if real-time PCR assay was not used. The real-time PCR assay demonstrated a detection limit of 2 cysts per reaction and 100% specificity and sensitivity compared to conventional methods. A genotype analysis targeting the beta-giardin gene allowed to identify 53 samples (23 patients) containing genotype A and 59 samples (45 patients) containing genotype B.

Infective colitis associated with human intestinal spirochetosis

Aim:  Our study reports the detection and identification of intestinal spirochetosis in patients with colonic diseases in a tertiary‐care hospital over a 12‐year period, and includes a description of all cases we diagnosed.

Evaluation of a real-time polymerase chain reaction assay for the detection of Dientamoeba fragilis ☆

The diagnostic value of a real-time polymerase chain reaction (PCR) assay targeting the 5.8S rDNA of Dientamoeba fragilis was investigated as compared with conventional parasitologic methods including cultivation testing 959 fecal samples from 491 patients attending a tertiary-care hospital and suspected of having an intestinal parasitosis. The real-time PCR assay revealed 117 additional D. fragilis-positive samples as compared with conventional methods, showing 100% sensitivity and specificity in our experience. On the whole, D. fragilis infection was detected in 186 samples from 105 patients (21.4%, third in frequency among the diagnosed intestinal parasitoses). The evaluated real-time PCR assay represents an effective tool to obtain both an accurate diagnosis and a reliable epidemiologic picture of dientamoebiasis.

Evaluation of Toxoplasma gondii Immunoglobulin G (IgG) and IgM Assays Incorporating the New Vidia Analyzer System

ABSTRACT The new Vidia system is a fully automated system based on chemiluminescence and antigen bound to magnetic microparticles, which allows a fast measurement of Toxoplasma gondii-specific immunoglobulin G (IgG) and IgM levels. The analytical performances of the Vidia Toxo IgG and IgM assays were compared with those of the automated Vidas, AxSYM, and Liaison Toxo IgG and IgM assays. The comparative evaluation was performed utilizing 204 frozen sera belonging to 166 subjects and 201 fresh sera collected from 198 subjects. For the Vidia Toxo IgG system, the sensitivities were 100% in both the retrospective and prospective studies, and specificities were 98.39% in the retrospective study and 100% in the prospective study, respectively. The sensitivities of the other three Toxo IgG assays were 100%, and the specificities ranged from 96.77% to 100%. For the Vidia Toxo IgM assay, the sensitivity and specificity were 100% in both the retrospective and prospective studies. The overall sensitivities and specificities of the other three Toxo IgM assays ranged from 80% to 100% and from 99.44% to 100%, respectively. In our study, the Vidia system revealed excellent sensitivity (100% for both IgG and IgM assays) and good specificity (99.25% for IgG and 100% for IgM assays).

An 8-year survey on the occurrence of imported malaria in a nonendemic area by microscopy and molecular assays.

Our study aimed to describe the occurrence of imported malaria in a nonendemic area (Parma, Italy) during the period 2000 to 2007, comparing the data obtained by microscopy and molecular assays targeting plasmodial 18S subunit rRNA gene. The prevalence of imported malaria in Parma was 21.8% by microscopy and 22.7% by polymerase chain reaction (PCR). Plasmodium falciparum accounted for 81.1% of the cases, followed by Plasmodium ovale (8.8%), Plasmodium vivax (3.8%), and Plasmodium malariae (1.9%). Mixed infections accounted for 4.4% of the cases. In this study, PCRs proved to be more sensitive and specific than microscopy and changed the picture of malaria epidemiology in Parma, detecting additional cases of malaria undiagnosed by microscopy and allowing speciation of plasmodia in cases misidentified by microscopy. Generally, imported malaria cases reflect the number of immigrants who visit their native countries, in particular, West Africa, explaining the increased prevalence of P. ovale cases among non-P. falciparum infections in Parma.