First detection of Cryptosporidium DNA in blood and cerebrospinal fluid of HIV-infected patients.

Human cryptosporidiosis is an intestinal infection caused by different species belonging to the genus Cryptosporidium in both immunocompetent and immunocompromised individuals. The life cycle of Cryptosporidium sp. when affecting the digestive system is well known but the infection of other organs is less studied. Molecular methods are necessary for species and subtypes identification. The goal of this work is to propose a new approach that contributes to the diagnosis of the extra-intestinal dissemination process of Cryptosporidium infection. Cryptosporidium sp. was detected in stool and biopsy samples of two HIV-infected patients. DNA was extracted from feces, biopsy specimens, blood, and cerebrospinal fluid (CSF). All samples were analyzed by nested PCR-RFLP of the 18S rDNA, real-time PCR, and gp60 subtyping. Cryptosporidium DNA was detected in stool and tissue samples and it was also present in blood and CSF samples. Both cases were characterized as Cryptosporidium hominis subtype IeA11G3T3. This is the first report that demonstrates the presence of Cryptosporidium DNA in blood and CSF of HIV-infected patients.

Genotyping of Toxoplasma gondii Directly from Human and Animal Biological Samples: From Partial Genotypes to a New Genotype.

Genotyping of Toxoplasma gondii is traditionally performed using DNA obtained from tachyzoites after isolation by bioassay in mice. In this study, genotyping of T. gondii was performed by multiplex nested polymerase chain reaction restriction fragment length polymorphism (Mn-PCR-RFLP) in DNA obtained from the lungs of experimentally infected mice, the hearts of naturally infected free-range chickens, and human blood samples of newborns with congenital toxoplasmosis. The efficiency of Mn-PCR varied according to the marker. We obtained complete genotypes of all of the mice lung samples. In chickens, total or partial genotyping was performed on all of the 15 samples. Two complete genotypes were obtained, including one identified for the first time, and another previously described in different hosts including dogs, cats, and humans. In blood from infants, partial genotypes were obtained in 8 of the 12 samples. Mouse bioassay is the most efficient method to obtain DNA from T. gondii , but direct tissue genotyping enhances the likelihood of obtaining molecular information on T. gondii and is an effective tool as a complement to isolation in mice. In this study, we genotyped Toxoplasma gondii directly from human (blood samples of newborns with congenital toxoplasmosis) and free-range chickens (hearts) by Mn-PCR-RFLP. We present partial and complete genotypes and provide technical and scientific information about T. gondii genotyping methods.

Features to validate cerebral toxoplasmosis.

INTRODUCTION: Neurotoxoplasmosis (NT) sometimes manifests unusual characteristics. METHODS: We analyzed 85 patients with NT and AIDS according to clinical, cerebrospinal fluid, cranial magnetic resonance, and polymerase chain reaction (PCR) characteristics. RESULTS: In 8.5%, focal neurological deficits were absent and 16.4% had single cerebral lesions. Increased sensitivity of PCR for Toxoplasma gondii DNA in the central nervous system was associated with pleocytosis and presence of >4 encephalic lesions. CONCLUSIONS: Patients with NT may present without focal neurological deficit and NT may occur with presence of a single cerebral lesion. Greater numbers of lesions and greater cellularity in cerebrospinal fluid improve the sensitivity of PCR to T gondii.

Features to validate cerebral toxoplasmosis

Introduction Neurotoxoplasmosis (NT) sometimes manifests unusual characteristics. Methods We analyzed 85 patients with NT and AIDS according to clinical, cerebrospinal fluid, cranial magnetic resonance, and polymerase chain reaction (PCR) characteristics. Results In 8.5%, focal neurological deficits were absent and 16.4% had single cerebral lesions. Increased sensitivity of PCR for Toxoplasma gondii DNA in the central nervous system was associated with pleocytosis and presence of >4 encephalic lesions. Conclusions Patients with NT may present without focal neurological deficit and NT may occur with presence of a single cerebral lesion. Greater numbers of lesions and greater cellularity in cerebrospinal fluid improve the sensitivity of PCR to T gondii. .

Conventional polymerase chain reaction for the diagnosis of neurotoxoplasmosis: comparison of three sets of primers for the B1 gene using CSF samples.

Polymerase chain reaction (PCR) has made a significant improvement in the diagnosis of toxoplasmic encephalitis (TE). Nevertheless, a wide variety of targets and primers has been used in different assays, and few comparative studies had been carried out. The aim of the present study was to compare the efficiency of 3 conventional PCR methods by using 3 sets of primers targeting the repetitive B1 gene in the diagnosis of TE. Diagnostic sensitivity and specificity of PCR and nested-PCR protocols were assessed for 207 (nested-PCR/T1-T4), 200 (nested-PCR/S1-AS1), and 206 (PCR/B22-B23) cerebrospinal fluid (CSF) samples, including AIDS and HIV-negative patients. The diagnostic sensitivity of PCR and nested-PCR assays was 50.85%, 68.97%, and 72.41% for T1-T4, S1-AS1, and B22-B23, respectively. The diagnostic specificity was high for all the assays showing values between 95% and 97%. In general, the best results were obtained for the B22-B23 set of primers, suggesting their usefulness compared with 2 nested-PCR protocols and showing that this simple and rapid strategy may be the preferred one for the diagnosis of TE in AIDS patients.

Toxoplasma gondii isolates: multilocus RFLP-PCR genotyping from human patients in Sao Paulo State, Brazil identified distinct genotypes.

This study investigated the genetic characteristics of Toxoplasma gondii samples collected from 62 patients with toxoplasmosis in Sao Paulo State, Brazil. DNA samples were isolated from blood, cerebrospinal fluid and amniotic fluids of 25 patients with cerebral toxoplasmosis and AIDS, two patients with acute toxoplasmosis, 12 patients with ocular toxoplasmosis, six newborns with congenital toxoplasmosis and 17 pregnant women with acute infection. Diagnosis of toxoplasmosis was based in clinical, radiological and laboratory features. Genotyping was performed using multilocus PCR-RFLP genetic markers including SAG1, SAG2, 5'- and 3'-SAG2, alt.SAG2, SAG3, BTUB, GRA6, C22-8, c29-2, L358, PK1 and Apico. Among the 62 clinical samples, 20 (32%) were successfully genotyped at eight or more genetic loci and were grouped to three distinct genotypes. Eighteen samples belonged to ToxoDB Genotype #65 and the other two samples were identified as ToxoDB Genotypes #6 and #71, respectively (http://toxodb.org/toxo/). Patients presenting Genotypes #6 and #71 had severe and atypical cerebral toxoplasmosis, characterized by diffuse encephalitis without extensive brain lesions. These results indicate that T. gondii Genotype #65 may have a high frequency in causing human toxoplasmosis in Sao Paulo State, Brazil. This unusual finding highlights the need to investigate the possible association of parasite genotypes with human toxoplasmosis.

[Molecular diagnosis of a fatal primary amoebic meningoencephalitis in Guadeloupe (French West Indies)]. / Diagnostic moléculaire d'une méningoencéphalite amibienne primitive à l'occasion d'un cas fatal en Guadeloupe.

We report the first case of primary amoebic meningoencephalitis in a 9-year-old boy in Guadeloupe. The outcome was rapidly fatal in 7 days. The patient presumably acquired the infection by swimming and diving in a basin supplied by natural thermal water 1 week before onset of the disease. The possibility of a free-living amoeba infection was suspected both on the negativity of all bacterial and viral initial tests and on the observation of peculiar cells in stained cerebrospinal fluid samples. Although the amoeba was not isolated, Naegleria fowleri could be identified by polymerase chain reaction with specific primers on DNA extracted from frozen cerebrospinal fluid samples. Furthermore, as the internal transcribed spacer (ITS1) region of DNA is variable in length between the different strains of N. fowleri, sequencing of the amplified ITS1 demonstrated that the responsible N. fowleri strain belongs to a common genotype present in the American and European continent.

Influence of neurotoxoplasmosis characteristics on real-time PCR sensitivity among AIDS patients in Brazil.

Cerebral toxoplasmosis among individuals with AIDS may be difficult to diagnose and needs to be differentiated from other neurological diseases. A validation study was performed on real-time PCR for detecting the B1 gene of Toxoplasma gondii in the blood and cerebrospinal fluid (CSF) of AIDS patients with cerebral toxoplasmosis. The study included 135 AIDS patients divided into two groups: Group I comprised 85 patients with neurotoxoplasmosis; and Group II comprised 50 patients with non-toxoplasmic neurological diseases. Real-time PCR on blood showed a sensitivity of 1.5%, specificity of 100.0%, positive predictive value (PPV) of 100.0% and negative predictive value (NPV) of 36.5%. CSF testing produced better results, with a sensitivity of 35.3%, specificity of 100.0%, PPV of 100.0% and NPV of 44.7%. The group presenting with pleocytosis and four or more encephalic lesions was associated with greater CSF positivity on PCR. In conclusion, real-time PCR on blood was not useful for diagnosis. CSF testing showed low sensitivity but high specificity. Greater numbers of lesions and greater CSF cellularity may improve the sensitivity of the method.

Neurotoxoplasmosis diagnosis for HIV-1 patients by real-time PCR of cerebrospinal fluid.

Encephalitis caused by Toxoplasma gondii is the most common cause of central nervous system damage in patients with acquired immunodeficiency syndrome (AIDS). Toxoplasma may infect any of the brain cells, thus leading to non-specific neurotoxoplasmosis clinical manifestations including focused or non-focused signs and symptoms of central nervous system malfunction. Clinical development ranges from insidious display during weeks to experiencing acute general confusion or ultimately fatal onset. Cerebral toxoplasmosis occurs in advanced stages of immunodeficiency, and the absence of anti-toxoplasmosis antibodies by the immunofluorescence method does not allow us to rule out its diagnosis. As specific therapy begins, diagnosis confirmation is sought through clinical and radiological response. There are few accurate diagnosis methods to confirm such cases. We present a method for T. gondii DNA detection by real time PCR-Multiplex. Fifty-one patients were evaluated; 16 patients had AIDS and a presumptive diagnosis for toxoplasmosis, 23 patients were HIV-positive with further morbidities except neurotoxoplasmosis, and 12 subjects were HIV-negative control patients. Real time PCR-Multiplex was applied to these patients' cephalorachidian liquid with a specific T. gondii genome sequence from the 529bp fragment. This test is usually carried out within four hours. Test sensitivity, specificity, positive predictive value, and negative predictive value were calculated according to applicable tables. Toxoplasma gondii assay by real time Multiplex of cephalorachidian fluid was positive for 11 out of 16 patients with AIDS and a presumptive diagnosis for cerebral toxoplasmosis, while none of the 35 control patients displayed such a result. Therefore, this method allowed us to achieve 68.8% sensitivity, 100% specificity, 100% positive predictive value, and 87.8% negative predictive value. Real time PCR on CSF allowed high specificity and good sensitivity among patients who presumably had cerebral toxoplasmosis. Since this is a low invasive method, it could be included in the diagnosis algorithm of patients with AIDS and central nervous system damage.

Detection of Toxoplasma gondii in cerebrospinal fluid from AIDS patients by nested PCR and rapid identification of type I allele at B1 gene by RFLP analysis.

Highly active antiretroviral therapy (HAART) has decreased the incidence of opportunistic infections in the central nervous system (CNS) in AIDS patients. However, toxoplasmic encephalitis (TE) still represents the most common cerebral mass lesion in patients infected with human immunodeficiency virus (HIV). The aim of this study was to evaluate nested PCR-B1 using cerebrospinal fluid (CSF) to detect Toxoplasma gondii DNA for the diagnosis of TE. A total of 114 samples were evaluated, and 33/44 samples from patients with TE were positive by PCR (sensitivity 75%), demonstrating the diagnostic usefulness of PCR technique. PCR-B1 products were analyzed by restriction fragment length polymorphism (RFLP) in 30 samples. Only type I allele at B1 was identified in these samples according banding patterns. This is the first report of evaluation of S1-AS1/S2-AS2 set of primers in more than 100 clinical samples as well as the first genotyping study of T. gondii in Cuba.

Neurotoxoplasmosis diagnosis for HIV-1 patients by real-time PCR of cerebrospinal fluid

Encephalitis caused by Toxoplasma gondii is the most common cause of central nervous system damage in patients with acquired immunodeficiency syndrome (AIDS). Toxoplasma may infect any of the brain cells, thus leading to non-specific neurotoxoplasmosis clinical manifestations including focused or non-focused signs and symptoms of central nervous system malfunction. Clinical development ranges from insidious display during weeks to experiencing acute general confusion or ultimately fatal onset. Cerebral toxoplasmosis occurs in advanced stages of immunodeficiency, and the absence of anti-toxoplasmosis antibodies by the immunofluorescence method does not allow us to rule out its diagnosis. As specific therapy begins, diagnosis confirmation is sought through clinical and radiological response. There are few accurate diagnosis methods to confirm such cases. We present a method for T. gondii DNA detection by real time PCR-Multiplex. Fifty-one patients were evaluated; 16 patients had AIDS and a presumptive diagnosis for toxoplasmosis, 23 patients were HIV-positive with further morbidities except neurotoxoplasmosis, and 12 subjects were HIV-negative control patients. Real time PCR-Multiplex was applied to these patients' cephalorachidian liquid with a specific T. gondii genome sequence from the 529bp fragment. This test is usually carried out within four hours. Test sensitivity, specificity, positive predictive value, and negative predictive value were calculated according to applicable tables. Toxoplasma gondii assay by real time Multiplex of cephalorachidian fluid was positive for 11 out of 16 patients with AIDS and a presumptive diagnosis for cerebral toxoplasmosis, while none of the 35 control patients displayed such a result. Therefore, this method allowed us to achieve 68.8 percent sensitivity, 100 percent specificity, 100 percent positive predictive value, and 87.8 percent negative predictive value. Real time PCR on CSF allowed high specificity...

Comparison of four DNA extraction methods from cerebrospinal fluid for the detection of Toxoplasma gondii by polymerase chain reaction in AIDS patients.

BACKGROUND: Toxoplasmosis is a serious and often life-threatening disease in immunodeficient patients. Polymerase chain reaction (PCR) assays allow a rapid diagnosis of Toxoplasma infection by direct detection of the parasite's DNA. To perform a sensitive, specific, and reliable PCR-based diagnostic test, the availability of pure DNA lacking PCR inhibitors as well as a rapid and easy-to-perform DNA extraction protocol are essential. The aim of the present study was to compare four DNA extraction methods for the detection of T. gondii on cerebrospinal fluid (CSF) using the PCR technology. MATERIAL/METHODS: Four DNA extraction methods (boiling, lysis + centrifugation, the miniMAG commercial system, and phenol-chloroform) were compared with respect to the time of completion, the manual labor involved, and PCR analytical sensitivity for the detection of T. gondii in CSF. The optimal DNA extraction method for the detection of the parasite was evaluated in CSF from 43 AIDS patients using the nest-PCR B1 assay. RESULTS: According to the time required for completion, labor, and PCR analytical sensitivity, the lysis + centrifugation protocol proved to be a simple, efficient, and economical in-house procedure to recover the T. gondii DNA present in the CSF. The diagnostic sensitivity of nest-PCR, according to Centers for Disease Control and Prevention (CDC) criteria, was 86.3% and the diagnostic specificity was 100%. CONCLUSIONS: We report a simple, rapid, reproducible, and economical in-house method for T. gondii DNA extraction from CSF. This method is recommended for diagnostic PCR of Toxoplasmic encephalitis (TE) in places with economical shortage.

Molecular identification of Trypanosoma cruzi I tropism for central nervous system in Chagas reactivation due to AIDS.

Trypanosoma cruzi lineages, microsatellite allelic polymorphism, and mithocondrial gene haplotypes were directly typified from peripheral blood and cerebrospinal fluid specimens of a Bolivian patient with Chagas disease with accompanying AIDS and central nervous system severe involvement. Of note, the patient's blood was infected by a mixture of T. cruzi I and T. cruzi IId/e polyclonal populations while the cerebrospinal fluid showed only a monoclonal T. cruzi I population. Our findings do not corroborate the original assumption of innocuity for T. cruzi I in the southern cone of the Americas and highlight lineage I tropism for central nervous system causing lethal Chagas reactivation.

Toxoplasma gondii: genotyping of strains from Brazilian AIDS patients with cerebral toxoplasmosis by multilocus PCR-RFLP markers.

This study investigated the genetic characteristics of the Toxoplasma gondii strains isolated from 87 patients with cerebral toxoplasmosis and AIDS, treated in Sao Paulo State, Brazil. The laboratorial diagnosis of cerebral toxoplasmosis was based on positive serological exams and PCR of blood and/or cerebrospinal fluid. Four markers (5'-SAG2, 3'-SAG2, SAG3 and GRA6) were chosen to analyze the samples. Each having clear resolution to distinguish the three clonal lineages after PCR amplified targets were treated with restriction enzyme digestion (PCR-RFLP). The genotyping provided the following results: 40 patients (46%) were infected with strains classified as type I; 4 (4%), as type III; 13 (15%) were infected with polymorphic strains (unusual genotype); 6 patients with type I or II alleles; and 15 (17%) patients had strains not classified for any marker. PCR-RFLP, also classified 9 (11%) clinical isolates as type II, which is uncommon in South America. However, the sequencing of the nested-PCR products (of SAG3 marker) of type II and polymorphic isolates (of 5'-SAG2, SAG3 and GRA6 markers) showed a nucleotide polymorphism compared with the archetypal clonal genotypes (types I, II and III) and these isolates were considered as polymorphic strains. The markers used here were inappropriate to distinguish the most isolates considered as polymorphic strains. These data confirm other studies showing the high rate of genetic polymorphism in T. gondii strains isolated in Brazil.

Early diagnosis of toxoplasmic encephalitis in AIDS patients by dot blot hybridization analysis.

Central nervous system toxoplasmosis is a life-threatening infection with a mortality rate of higher than 60%. An early and rapid diagnosis is important for effective treatment of the disease. A new approach for detection of cerebral toxoplasmosis is described here. DNAs extracted from cells in cerebrospinal fluid samples (0.3 to 0.8 ml) of patients suspected of having cerebral toxoplasmosis were analyzed by a dot blot hybridization technique. A highly repetitive DNA sequence of Toxoplasma gondii (ABGTg4) was nonisotopically labelled with digoxigenin-dUTP and used as a specific DNA probe. Four of six patients analyzed gave positive signals in our hybridization assay. Two of them recovered with pyrimethamine-sulfadiazine, a drug recommended for treatment of toxoplasmosis. The other two patients with positive signals died soon after diagnosis. Patients with negative signals were found to suffer from mycobacterial infection (patient 1) or varicella-zoster virus infection (patient 6).