Occurrence and genetic evaluation of potentially pathogenic Acanthamoeba genotypes in nasal mucosa of immunocompromised patients: a case-control study in Iran.

BACKGROUND: The occurrence of granulomatous amoebic encephalitis (GAE) was investigated due to the exposure of a large number of immunocompromised patients to opportunistic Acanthamoeba infections, which in most cases are fatal. METHODS: In this case-control study, 160 samples from the nasal mucosa of immunocompromised patients were collected between February 2019 to February 2020 in Isfahan, central Iran, using sterile cotton swabs; 150 ethnically matched controls were included. The pathogenic potential of the identified isolates was evaluated using temperature and osmotolerance assays. The identification of Acanthamoeba infection was confirmed by both morphological and phylomolecular tools. RESULTS: Of 310 collected samples, 32 strains, including 25 (15.6%) and 7 (4.6%) isolates, were positive for the Acanthamoeba genus in the patient and control groups, respectively. The topology of the phylogenetic tree indicated that all the Acanthamoeba strains belonged to the T4 genotype. Only five of the isolates genotyped as T4 were positive for potential pathogenic assays. The heterogeneity analysis of 18S ribosomal RNA sequences of Acanthamoeba in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) and hepatitis B and C patients revealed significant genetic diversity (haplotype diversity [Hd] 0.511) compared with that of healthy individuals (Hd 0.210). CONCLUSIONS: The circulation of pathogenic isolates of Acanthamoeba, particularly in HIV/AIDS patients, along with their genetic traits, indicates that clinicians should be more aware of fatal cases of GAE, especially in suspected encephalitis, in Iran and worldwide.

Phylogeography, genetic variability and structure of Acanthamoeba metapopulations in Iran inferred by 18S ribosomal RNA sequences: A systematic review and meta-analysis.

OBJECTIVE: To verify phylogeography and genetic structure of Acanthamoeba populations among the Iranian clinical isolates and natural/artificial environments distributed in various regions of the country. METHODS: We searched electronic databases including Medline, PubMed, Science Direct, Scopus and Google Scholar from 2005 to 2016. To explore the genetic variability of Acanthamoeba sp, 205 sequences were retrieved from keratitis patients, immunosuppressed cases and environmental sources as of various geographies of Iran. RESULTS: T4 genotype was the predominant strain in Iran, and the rare genotypes belonged to T2, T3, T5 (Acanthamoeba lenticulata), T6, T9, T11, T13 and T15 (Acanthamoeba jacobsi). A total of 47 unique haplotypes of T4 were identified. A parsimonious network of the sequence haplotypes demonstrated star-like feature containing haplogroups IR6 (34.1%) and IR7 (31.2%) as the most common haplotypes. In accordance with the analysis of molecular variance, the high value of haplotype diversity (0.612-0.848) of Acanthamoeba T4 represented genetic variability within populations. Neutrality indices of the 18S ribosomal RNA demonstrated negative values in all populations which represented a considerable divergence from neutrality. The majority of genetic diversity belonged to the infected contact lens and dust samples in immunodeficiency and ophthalmology wards, which indicated potential routes for exposure to a pathogenic Acanthamoeba sp. in at-risk individuals. A pairwise fixation index (FST) was from low to high values (0.02433-0.41892). The statistically FST points out that T4 is genetically differentiated between north-west, north-south and central-south metapopulations, but not differentiated between west-central, west-south, central-south, and north-central isolates. CONCLUSIONS: An occurrence of IR6 and IR7 displays that possibly a gene flow of Acanthamoeba T4 occurred after the founder effect or bottleneck experience through ecological changes or host mobility. This is the first systematic review and meta-analysis providing new approaches into gene migration and transmission patterns of Acanthamoeba sp, and targeting at the high-risk individuals/sources among the various regions of Iran.

The first morphometric and phylogenetic perspective on molecular epidemiology of Echinococcus granulosus sensu lato in stray dogs in a hyperendemic Middle East focus, northwestern Iran.

BACKGROUND: Hydatidosis is considered to be a neglected cyclo-zoonotic disease in Middle East countries particularly northwestern Iran which is caused by metacestode of tapeworm Echinococcus granulosus sensu lato. Human hydatidosis is a high public health priority in the area, however there is little known from a morphometric and phylogenetic perspective on molecular epidemiology of adult Echinococcus spp. in Iranian stray dogs. METHODS: 80 dogs (38 males and 42 females) were collected during June 2013 to April 2014 in northwestern Iran. The isolated parasites from each dog were distinguished by morphometric keys including small, large hook length and blade length. Subsequently, isolates were confirmed by sequencing of mitochondrial cytochrome oxidase subunit 1 gene. RESULTS: 16 (8 males and 8 females) (Prevalence 20%) out of 80 dogs were infected to genus Echinococcus. With regard to demographic factors, the frequency of parasitism in both male, female adults and their age groups showed no difference (P > 0.05). The phylogenetic analyses of cox1 sequences firmly revealed the 13 sheep strains (G1), one buffalo strain (G3), one camel strain (G6) and one mixed infection. The findings of rostellar hook morphology show an intraspecies variation range among G1 isolates. However, hook measurements in Echinococcus derived from G1 (sheep strain) were not a significant difference from those G6 and G3 strains. Six unique haplotypes were identified containing a high range of diversity (Haplotype diversity 0.873 vs. Nucleotide diversity 0.02). CONCLUSIONS: First presence of camel strain (G6) in this region seems to indicate that potential intermediate hosts play a secondary role in the maintenance of camel-dog biology. Current findings have heightened our knowledge about determination of Echinococcus prevalence, strains of taxonomy and genotypic trait of parasite in Iranian stray dogs which will also help in the development of strategies for monitoring and control of infected stray dogs in the area.