Presence of Balamuthia mandrillaris in hot springs from Mazandaran province, northern Iran.

Balamuthia mandrillaris is an opportunistic free-living amoeba that has been reported to cause cutaneous lesions and Balamuthia amoebic encephalitis. The biology and environmental distribution of B. mandrillaris is still poorly understood and isolation of this pathogen from the environment is a rare event. Previous studies have reported that the presence of B. mandrillaris in the environment in Iran may be common. However, no clinical cases have been reported so far in this country. In the present study, a survey was conducted in order to evaluate the presence of B. mandrillaris in hot-spring samples of northern Iran. A total of 66 water samples were analysed using morphological and molecular tools. Positive samples by microscopy were confirmed by performing PCR amplification of the 16S rRNA gene of B. mandrillaris. Sequencing of the positive amplicons was also performed to confirm morphological data. Two of the 66 collected water samples were positive for B. mandrillaris after morphological and molecular identification. Interestingly, both positive hot springs had low pH values and temperatures ranging from 32 °C to 42 °C. Many locals and tourists use both hot springs due to their medicinal properties and thus contact with water bodies containing the organism increases the likelihood of infection. To the best of our knowledge, this is the first report on the isolation of B. mandrillaris from hot-spring sources related to human activity. Therefore, B. mandrillaris should be considered as a possible causative agent if cases of encephalitis are suspected following immersion in hot springs in addition to Acanthamoeba and Naegleria.

Occurrence of pathogenic Acanthamoeba genotypes in nasal swabs of cancer patients in Iran.

Incidences of Acanthamoeba granulomatous encephalitis (AGE) have been increased due to a rise in the number of high-risk people, such as immunodeficient patients. Indeed, immunosuppress situation can render the patient in acquiring opportunistic Acanthamoeba infections. In this study, analysis was carried out to verify the presence of free-living amoebae of Acanthamoeba genus in nasal swabs of cancer patients in hospitals of Tehran, Iran. Detection of isolates was based on morphotyping and PCR sequencing of the Diagnostic Fragment 3 (DF3) to identify strains at the genotype level. In addition, the pathogenic potential of the isolates was assayed using temperature and osmotolerance assays. The obtained results revealed that nine isolated strains belonging to T4 genotype-exhibited pathogenic potential. After sequencing, genotype T4 was found to be the most common one in the samples included in this study. Genotype T3 and T5 were also identified. To the best of our knowledge, this is the first study on the typing of Acanthamoeba strains at the genotype level in cancer patients in Iran and worldwide.

Comparison of the RE and B1 gene for detection of Toxoplasma gondii infection in children with cancer.

Early, accurate and effective diagnosis of toxoplasmosis can make an important contribution to the prevention and control of disease, especially in people who are at risk. In this study, two commonly used genomic repeats of Toxoplasma gondii, RE (GenBank accession number AF146527) and B1, were compared to each other in nested-PCR assay. Five hundred and thirty-five blood samples from children with leukemia were tested for the presence of T. gondii antibodies using enzyme immunoassays. One hundred and ten DNA samples of these patients (50 IgM+, IgG+, 10 IgM-, IgG+, and 50 IgM-, IgG-) were analyzed by nested-PCR. The specificity of two nested PCR assays was determined using the DNA samples of other parasites and human chromosomal DNA. As a result, 82% (41/50) and 68% (34/50) of the IgM+, IgG+ samples were positive on duplicate RE and B1-nested PCR analyses, respectively. None of the 10 IgM-, IgG+ seropositive samples was detected positive after testing RE and B1-nested PCR assays in duplicate. One (2%) of the 50 seronegative samples was positive by duplicate RE-nested PCR but none of them were positive by duplicate B1-nested PCR. The detection limit of the RE-nested PCR assay was 640 fg of T. gondii DNA whereas this rate for B1-nested PCR was 5.12 pg of the DNA template. No cross-reactivity with the DNA of other parasites and human chromosomal DNA was found. The results indicate that an RE-based nested PCR assay is more sensitive than B1 genomic target, of those tested, for detection of T. gondii. It is noteworthy that in comparison with B1-nested PCR, RE-nested PCR could detect the T. gondii DNA in seronegative samples too.

First report of vannellidae amoebae (vannella spp.) isolated from biofilm source.

BACKGROUND: Members of the Vannellidae family are free-living amoebae (FLA) distributed mainly in water and soil sources. The present study reports the first isolation of this genus in the biofilm source from hospital environment in Tehran, Iran. METHODS: Biofilm samples were collected from hospital environment. Cultivation was performed in non-nutrient agar covered with a heat-killed Escherichia coli. Cloning of the suspected amoebae was done. PCR amplification and Homology analysis using the Basic Local Alignment Search Tool (BLASTn) was performed to search for the most similar reference sequences. RESULTS: Microscopic examination showed numerous fan-shaped amoebae and peculiar cysts different to the usual shape of typical FLA. Sequence analysis of the PCR- product revealed that the suspected amoebae are highly homologous with Vannella spp. gene (99% identity and 100% query coverage) available in the gene bank database. CONCLUSION: Although Vannella spp. is not proved to be pathogenic itself, but they are capable of harboring pathogenic intracellular organisms such as Microsporidian parasites. Thus, identification of such amoebae can be of clinical importance, as they could lead to transmission of other pathogens to human.