Contamination of fresh vegetables in municipal stores with pathogenic Acanthamoeba genotypes; a public health concern

Acanthamoeba spp. cause keratitis and encephalitis, and are a proper carrier of foodborne pathogens. A total of 70 samples including garden cress, chives, mint, parsley, and basil were collected. Samples were cultured onto a 2% non-nutrient agar medium. The cultures were analyzed using morphological and molecular techniques. In total, 18 (25.7%) out of 70 samples were positive including garden cress 10/22 (45.45%), chives 3/12 (25%), mint 2/13 (15.38%), basil 2/13 (15.38%), and parsley 1/10 (10%). The diagnostic fragment 3 was successfully sequenced in 15 samples and represented 11 (73.3%) T4, three (20%) T5, and one T9 genotypes. In addition, three, two, and one strains, belonging to the genotypes T4, T5, and T9 were ranked highly pathogenic. This is the first study reporting contamination of the most commonly consumed fresh vegetables with pathogenic Acanthamoeba genotypes. Our findings signify the public health concerns due the contamination of vegetables in municipal public markets.

Molecular Identification, Subtypes Distribution, and Alleles Discrimination of Blastocystis sp., Isolated from Immunocompromised Subjects in Iran

Background:

Blastocystis sp., is a prevalent protist isolated from humans and animals, which its opportunistic role in immunocompromised patients is still controversial. The current study aimed to evaluate the subtype and alleles distribution of Blastocystis sp., among immunocompromised patients.

Methods:

Totally, 33 microscopically Blastocystis-positive stool samples, isolated from Guilan province during April 2018 to May 2019 were investigated. Total DNA extraction was performed and the barcoding region of the small subunit ribosomal RNA (SSU rRNA) gene was amplified. Targeted fragments were sequenced to characterize subtypes and relevant alleles. Phylogenetic tree was constructed using Maximum-likelihood and Tamura 3-parameter to illustrate the correlation between subtypes and certain immunodeficiency.

Results:

Subtype analysis revealed the presence of ST1, ST2, ST3, and ST7 among 13/33 (39.4%), 5 (15.2%), 14/33 (42.4%), and 1/33 (3%), of samples, respectively. ST1 was the major subtype among cancer patients 5/7 (71.42%), while ST3 was the predominant subtype among rheumatoid arthritis (RA) patients 3/6 (50%), internal ward patients 5/10 (50%), and asthma and allergy patients 2/3 (66.66%). ST7 was isolated from a patient hospitalized in internal ward. No significant correlation was seen between the type of immunodeficiency and subtypes (P-value = 0.771). The phylogenetic tree showed no separation regarding the type of immunodeficiency.

Conclusion:

Among studied immunocompromised patients, ST3 was the most prevalent subtype followed by ST1. There was no specific correlation between subtypes and alleles with type of immunodeficiency. Putative zoonotic alleles were highlighted the probability of zoonotic transmission for Blastocystis sp.

Association of Blastocystis ST6 with higher protease activity among symptomatic subjects

BACKGROUND

Blastocystis sp. is an anaerobic intestinal protozoan parasite of humans and a wide range of animals worldwide. In the current study the correlation between the cysteine protease activity of clinical samples of Blastocystis sp. ST1-3 and 6 with the levels of pro-inflammatory cytokines was evaluated.

METHODS

Stool samples were collected from subjects with or without clinical symptoms. All samples were cultivated in DMEM medium. The bacteria were eliminated or reduced in Blastocystis sp. positive samples subtypes 1-3 and 6 by a variety of antibiotics and consecutive sub-cultures. To prepare parasite lysate, 1 × 105 Blastocystis sp. from each isolate were harvested and lysed using freeze-thaw. Protease activity of each isolate was measured and the gene expression of pro-inflammatory biomarkers in HT-29 cell line sensed by isolates was investigated using quantitative Real-time PCR.

RESULTS

Protease activity assay showed inter- and intra-subtype variations among subtypes regarding the presence of symptoms, while the protease activity of symptomatic isolates was higher than asymptomatic isolates. The highest and lowest levels of protease activity were seen in ST6 and ST2, respectively. However, patterns of the expression of pro-inflammatory biomarkers in HT-29 cell line was different regarding the presence of symptoms and time points. There was no significant correlation between protease activity of different subtypes with the expression levels of pro-inflammatory biomarkers.

CONCLUSIONS

Our study indicated a higher protease activity among isolates from symptomatic compared to asymptomatic subjects, suggesting functional role for proteases in clinical symptoms due to Blastocystis sp. The lack of correlation between the levels of expression of pro-inflammatory biomarkers with subtypes regarding the presence of clinical symptoms proposes the importance of host-related factors in presentation of clinical symptoms.

Molecular Identification of Pathogenic Free-Living Amoeba from Household Biofilm Samples in Iran: A Risk Factor for Acanthamoeba Keratitis

Free-living amoeba (FLA) are ubiquitously distributed in the environment. However, they are also the causative agents of opportunistic infections in humans and other animals. A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. Moreover, FLA have been detected in various biofilms around the world. Therefore, the present study aimed to check for presence of FLA in samples from household biofilms in Iran and to characterize them at the molecular level. A total of 69 biofilm samples collected from showerheads, kitchen areas, and bathroom sinks were analyzed. Positive samples for FLA were characterized at the morphological and molecular levels. Furthermore, the results of morphology analysis indicated that 26.08% (18/69) of biofilm samples were positive for Acanthamoeba spp., Vermamoeba genus, and Vahlkampfiids. According to sequence analysis, five strains of Acanthamoeba isolates related to the T4 genotype and two strains belonged to the T2 genotype. In addition, the pathogenic potential of Acanthamoeba-positive isolates was conducted using the tolerance ability test. The results of BLASTn of Vermamoeba sequences were similar to what was expected for Vermamoeba vermiformis. The above-mentioned reasons revealed that the relative high contamination of household biofilm samples with FLA may pose a risk for people using soft contact lenses and for patients with traumatic cataract. Our finding proposes that filtration should be performed in shower heads and indicates the need to monitor people at increased risk of Acanthamoeba keratitis.

Study of prevalence, distribution and clinical significance of Blastocystis isolated from two medical centers in Iran

AIM

This study aimed to survey prevalence and clinical significance of Blastocystis among symptomatic and asymptomatic groups.

BACKGROUND

Blastocystis is a prevalent microorganism that is found in intestine of human and majority of animals. However, most studies have failed to establish correlation between the presence of the parasite and clinical manifestations.

METHODS

from Dec 2016 to Jun 2017, 554 stool samples were collected from symptomatic and asymptomatic subjects referred to Imam Hossein Hospital and Gastroenterology and Liver Diseases Research Institute, Tehran, Iran. All samples were concentrated using conventional formalin-ethyl acetate concentration and then were microscopically examined using Lugol's iodine staining and light microscope. The fresh stool samples were also cultivated in DMEM medium and were examined for growth of Blastocystis every 48 hours with direct smear slides for 10 days.

RESULTS

Blastocystis was observed among 93 (16.8%) of stool samples cultivated in DMEM. The findings represented that 64/398 (16.08%) and 29/156 (18.58%) of asymptomatic and symptomatic patients were infected with Blastocystis, respectively. In addition, there was no significant correlation between presence of symptoms and carrying Blastocystis (P=0.528), although statistically significant association was observed between presence of urticaria and carrying Blastocystis (P<0.05). Furthermore, a statistically significant correlation between observing the parasite and different age groups was seen (P<0.05).

CONCLUSION

Blastocystis is a prevalent parasitic eukaryote among symptomatic and asymptomatic populations despite the higher prevalence among symptomatic group that suggests the chance of infection with Blastocystis raises with age.

Isolation and molecular characterization of Acanthamoeba genotypes isolated from soil sources of public and recreational areas in Iran

Pathogenic strains of Acanthamoeba are causative agents of a sight threating infection of the cornea known as Acanthamoeba keratitis. AK cases have been reported in Iran recently due to inappropriate usage of contact lens maintenance and most patients report a contact with contaminated sources such as dust, water or soil. Sixty soil samples were collected from public and recreational areas in the province of East Azerbaijan, Iran and checked for the presence of Acanthamoeba spp. Samples were cultured on non-nutrient agar plates seeded with heat killed Escherichia coli. PCR and sequencing of the DF3 region were carried out in order to genotype the isolated strains of Acanthamoeba. Thermotolerance and osmotolerance assays were performed in order to investigate the pathogenic potential of isolated Acanthamoeba strains. Acanthamoeba spp. was isolated from 41.6% of soil samples and genotyping of the strains resulted in the identification of genotypes T3, T4, T5 and T11. Most of the isolates belonging to genotypes T3 and T4 showed high pathogenic potential, indicating that they might present a potential health hazard for humans and other animals in this region. To the best of our knowledge, this is the first report on the identification of genotypes T3 and T11 from soil sources in the country.

Isolation of Balamuthia mandrillaris from soil samples in North-Western Iran

Balamuthia mandrillaris is an opportunistic free-living amoebae (FLA) which has been reported as the causative agent of the fatal Balamuthia amoebic encephalitis (BAE). Currently, the transmission dynamics of this pathogen remain poorly understood although the organism has been associated with soils, and thus, soil exposure has been identified as a risk factor for this pathogenic amoeba. Nevertheless, environmental isolation of B. mandrillaris is a rare event and strains of this amoebic species have been isolated from soil and dust sources only in seven previous reports (Iran, Mexico, USA, Peru, Costa Rica, Guinea Bissau, and Jamaica). In Iran, a previous study reported the isolation of B. mandrillaris from dust collected in the city of Tehran and free of known infectious involvement. Therefore, in this work, 55 soil samples collected from public and recreational areas of East Azerbaijan, North-Western Iran, were investigated for the presence of this pathogen. Samples were cultured in 2% non-nutrient agar plates and were monitored for the presence of B. mandrillaris-like trophozoites and/or cysts. Those samples that were positive for these amoebae by microscopic criteria were then confirmed by PCR amplification and DNA sequencing of the mitochondrial 16S ribosomal DNA (rDNA) of B. mandrillaris. The obtained results revealed the presence of this emerging pathogen in 5 of 55 samples included in the study. Homology analysis of the obtained DNA sequences revealed high similarity with previously isolated strains from clinical and environmental sources. To the best of our knowledge, this is the first report on the isolation of B. mandrillaris from soil sources in Iran related to human activity and the second time that this pathogen is isolated from the environment in this country.

Evaluation of the alum-naloxone adjuvant activity against experimental murine leishmaniasis due to L. major

Leishmaniasis is caused by intracellular parasites of Leishmania species, which are transmitted by the bite of the sandfly. Recovery and protection against the infection depends on the induction of a strong Th1 type of immune response. Vaccination of mice with the opioid antagonist naloxone can promote the activation of the Th1 responses. We studied the efficacy of the mixture of naloxone and alum, as an adjuvant, to enhance immune responses and induce protection against Leishmania major infection in BALB/c as a susceptible mouse model. BALB/c mice were immunized with Ag-naloxone-alum, Ag-alum, Ag-naloxone or PBS subcutaneously three times at 2-week intervals. The humoral and cellular specific immune responses were assessed 2 weeks after the last immunization and compared with the control mice. Our results indicated that the administration of alum-naloxone as an adjuvant increased the capability of L. major promastigote antigens to enhance lymphocyte proliferation, the levels of IFN-γ, and the IFN-γ/IL-5 ratio. The results of DTH showed that there were no significant differences in footpad swelling between the groups of immunized mice as compared with the non-vaccinated control group; however, no significant differences were observed in the survival rate among groups. It can be concluded that although immunization with the alum-naloxone mixture in combination with the autoclaved L. major promastigote antigens could enhance cellular immunity and shift the immune response to a Th1 pattern, it could not protect the mice against Leishmania major infection.