Microbial Biofilms as a Risk Factor for Acantahmoeba keratitis

Members of the protozoan genus Acanthamoeba are free-living amoebas and the primary causative agent ofamoebic keratitis and granulomatous encephalitis. Amoebic keratitis mainly occurs in individuals who wearsoft contact lenses following trauma and exposure to contaminated sources. As the survival, growth, andmultiplication of this protozoan increases in biofilms, which is the microbial accumulation, several cases ofamoebic keratitis have been reported as co-infections with bacteria, especially Pseudomonasaureginosa. Pseudomonas improves the binding of this protozoan to soft lens surfaces by its special surfaceenzymes, resulting in Acanthamoeba keratitis and sometimes mixed infection. Biofilm accumulatesmicroorganisms, including bacteria and fungi, on living and non-living surfaces. The firm attachment of thesemicrobial accumulations to the surface can cause various diseases and resistance to treatment. The critical pointis that bacteria have less destructive effects in the plantonik state, and when the specific signals of thesemicrobiome cause the recall of other microorganisms and their interaction, they lead to problems.Unfortunately, the ocular defense barrier, which includes the eyelids, lacrimal glands, and tears, cannot killmicrobial agents when microorganisms accumulate and adhere firmly to the lens surfaces. Due to the greatimportance of AK, especially in medical contact lens users, biofilm formation is an important issue that hasbeen considered in recent years. Biofilm formation-induced drug resistance, which is caused by thedisproportionate density of microorganisms on the inner and outer surfaces of the biofilm. There are severalways to prevent the formation of biofilms on the surfaces of contact lenses, including the use of antimicrobialpeptides and various antibiotics and coating them on the inner surface of contact lenses to slow-release ofantibiotics and prevent biofilm formation. In the present review article, we aimed to introduce biofilms as oneof the important risk factors for developing Acanthamoeba keratitis and prevention ways of biofilms formation

Free Living Amoeba Belonging to Vannella Spp. Isolated from a Hotspring in Amol City, Northern Iran

Background: Free-living amoebae have various genera that are found in several environmental niches such as soil, freshwater, dust, seawater and hotsprings. Most of Free-living amoebae are normally harmless to humans. However, some ameoba such as Acanthamoeba and also Naegleria fowleri, Balamuthia manderillaris and Sappinia are identified as opportunistic and pathogenic amoebae that can cause eye diseases, encephalitis, and meningoencephalitis in human. Vannellidae are a family of free-living amoebae and exist mainly in soil, freshwater, and marine habitats. This amoeba is nonpathogenic for human, but can act as a Trojan horse for other pathogens such as Microsporidia. The present study reports the occurrence of Vannella spp. in a hotspring of Amol city.Materials and Methods: 22 samples were taken from hotsprings of Mazandaran province during our previous study. The plates were checked for the presence of Vannella spp. according to the specific morphological criteria. DNA extraction, PCR and sequencing was performed on the positive isolate.Results: The result showed that one plate contained fan-shaped amoebae suspected to Vannella spp. PCR analysis and sequencing was confirmed the occurrence of Vannella spp. in one sample of a hot spring of Amol, northern Iran.Conclusion: The result confirmed the presence of Vannella amoebae in the hotspring of Amol city. More studies are needed to clarify the real distribution of Vannella spp. in environmental niches and its pathogenic potential in Iran and worldwide

Trichomonas vaginalis Pathogenesis: a Narrative Review

In the latest articles which were published during 2013-2014, Trichomonas vaginalis (T. vaginalis) was mentioned as a neglected sexual transmission disease (STD), while the exact mechanism of its pathogenesis has not been cleared yet. Although trichomonasiasis is easy curable, there is concern that resistance to drug are increasing. This common infection as concerning the important public health implications needs more research to be done for understanding the diagnosis, treatment, immunology and pathogenesis. In this review we searched all valuable and relevant information considering the pathogenesis of T. vaginalis. We referred to the information databases of Medline, PubMed, Scopus and Google scholar. The used keywords were the combinations of T. vaginalis and words associated with pathogenicity. This review discusses the host-parasite interaction and pathogenicity of this parasite

Anti-Acanthamoeba Activities of Chloroformic Fractions of Trigonella Foenum Graecum (Seed) and Their Cytotoxity on Mice Macrophage Cell

Background: Acanthamoeba keratitis (AK) is potentially a sight-threatening infection and its treatment is challenging. This is mainly due to presence of resistant cyst form. Indeed, cysts are highly resistant to current available drugs. Chemical drugs are toxic to human keratocytes. It should also be mentioned that most available anti-Acanthamoeba drugs are poorly cysticidal, In Iran and worldwide, AK cases continue to rise and therefore, novel effective drugs are urgently needed for the treatment of AK.Materials and Methods: In the present study, the in vitro activity of serial dilutions (10, 15, 20 and 25 mg/mL) of chloroformic fractions including primary chloroformic fraction (minimum amount of chloroform), middle chloroformic fraction and remaining chloroformic fraction (most amount of chloroform) of Trigonella foenum graecum seed were evaluated against Acanthamoeba trophozoites and cysts. Cytotoxic assay of fractions at different concentrations (25, 50, 100, 200, 300, 400, 500 mg/ml) of test material was identified on mice Macrophage cells using MTT method.Results: The obtained results revealed that the tested fractions presented anti-amoebic activities in a time and dose dependent cycle. Anti-Acanthamoeba activity of remaining chloroformic fraction was more than other fractions. Trophozoites/cysts were eliminated when incubated with 15 and 20 mg/ml concentrations of remaining chloroformic fraction after 24 hours. Viability of macrophage cells was noted 100 % with 25 and 50 mg/ml concentration of remaining chloroformic fraction. Our results indicate that the plant fractions are safe for mammalian cells.Conclusion: Further studies should be performed in order to detect the active chemical compounds which could be used for the development of novel therapeutic approaches against Acanthamoeba infections. To the best of our knowledge, this is the first study on the activity of chloroformic fractions of Trigonella foenum graecum (seed) against Acanthamoeba spp

Contamination of tap water sources to Acanthamoeba spp. in selected cities of Hormozgan province, Iran

Background    Free-living amoeba (FLA) such as Acanthamoeba are ubiquitous and amphizoic protozoan parasites. These parasites can cause severe human infections. Water resources are one of the important habitats for FLAs. Waters in tanks and wells can be a habitat for Acanthamoeba species, particularly in warm climates. The present study was conducted to evaluate the presence of Acanthamoeba species in tap water resources of selected cities of Hormozgan Province, Southern Iran.Material and methods In this cross sectional study, 50 water samples (approximately 500 mL) were collected from tap water resources (25 samples from tanks and 25 samples from wells) of Hormozgan province. The samples were filtered, cultured on 1.5% non-nutrient agar medium. After incubation at room temperature, cloning was performed. Investigation of Acanthamoeba species was performed using the microscopic method and page key.Results Out of 50 samples, 14 samples (28%) were found positive. Out of 25 examined well samples 9 samples (36%) were found contaminated with Acanthamoeba spp., while only 5 (20%) of 25 tank samples were found positive. All samples were cloned successfully.Conclusion The high occurrence of Acanthamoeba spp. in water resources of Hormozgan province could be as a hazard for public health of the region, and using effective disinfectants and accurate monitoring may be a good suggestion. 

A survey of Free-Living Amoebae (FLAs) in Nasal Mucosa of Healthy Individuals using Culture-based Method

Free-living amoebas (FLAs) are facultative parasites, and some of them can be highly pathogenic for animals and humans. These protozoan are found in abundance in environmental resources such as freshwater and soil, and thus the possible colonization of such FLA is probable. Our previous studies showed that Acanthamoeba spp. can colonize nasal mucosa of immunosuppressed patients. However, there was no report of colonization of free-living amoebae in healthy individuals in Iran.  The present study was conducted to investigate the possibility that FLAs are the normal flora of the nasal mucosa. Overall, 46 nasal swab samples were collected from healthy individuals and cultured on a 1.5% non-nutrient agar (NNA) plate enriched with a lawn of heat-killed Escherichia coli. The plates were incubated at room temperature. After one week, the plates were microscopically examined, and this was continued for one month. None of the samples were found positive for FLAs. Our findings may indicate that FLAs are not the normal flora of the nasal mucosa, or their number is so limited in the nasal mucosa that they cannot be isolated by the method used. However, supplementary and comprehensive studies are recommended

Reporting of T4 Genotype of Acanthamoeba Isolates in Recreational Water Sources of Gilan Province, Northern Iran

Background: Acanthamoeba spp. is the causative agent of blindness keratitis and fatal encephalaitis. Presence of Acanthamoeba spp. in a wide variety of niches such as different water types can lead to exposure of high risk people such as contact lens wearers. The main aim of the present study was to explore the occurrence of Acanthamoeba genotypes in the recreational water sources using both morphological and molecular approaches in Gilan province, Iran.Materials and Methods: Overall, 50 samples were collected from recreational water sources including man- made and natural waters in Gilan province. Filtration and cultivation of samples was performed using non-nutrient agar. Cloning of Acanthamoeba spp. was done to eliminate bacterial and fungi contamination. PCR amplification and sequencing were performed using genus-specific primer pair. Genotype identification was based on homology analysis of 18S rRNA gene (DF3) of the obtained sequences with the available genes in the gene bank data base.Results: Out of 50 water samples, 15 (30%) were positive for Acanthamoeba trophozoites and cysts according to morphological criteria. Cloning of 13 isolates (26%) was done successfully. Molecular analysis of 13 Acanthamoeba strain revealed that all isolates were belonged to potentially pathogenic T4 genotype.Conclusion: T4 genotype is the main cause of Acanthamoeba-related infections. Presence of Acanthamoeba belonged to T4 genotype in recreational water sources is of concern for high risk people. Alarming sign and education to high risk people is of utmost importance to prevent such infections

Occurrence of Potentially Pathogenic Bacterial-Endosymbionts in Acanthamoeba Spp

Background:Acanthamoeba- bacteria interactions enable pathogenic bacteria to tolerate harsh conditions and lead to transmission to the susceptible host. The present study was aimed to address the presence of bacterial endosymbionts of Acanthamoeba isolated from recreational water sources of Tehran, Iran. To the best of our knowledge this is the first study regarding occurrence of bacteria in environmental canthamoeba spp. in Iran. Methods:A total of 75 samples of recreational water sources were collected. Samples were cultured on non- nutrient agar 1.5% plates. Positive Acanthamoeba  spp. were axenically grown. DNA extraction and PCR reaction was performed using JDP1-2 primers. All positive samples of Acanthamoeba were examined for the presence of endosymbionts using staining and molecular methods. The PCR products were then sequenced in order to determine the genotypes of Acan-thamoeba and bacteria genera. Results:Out of 75 samples, 16 (21.3%) plates were positive for Acanthamoeba according to the morphological criteria. Molecular analysis revealed that Acan-thamoeba belonged to T4 and T5 genotypes. Five isolates (35.7%) were positive for bacterial endosymbionts using staining method and PCR test. Sequencing of PCR products confirmed the presence of Pseudomonas aeruginosa and Agrobacterium tumefasiens. Conclusion:The presence of Acanthamoeba bearing pathogenic endosymbionts in water sources leads us to public health issues including improved sanitation and decontamination measures in recreational water sources in order to prevent amoebae-related infection. To the best of our knowledge this is the first report regarding the isolation of A. tumefasiens from Acanthamoeba in Iran and world-wide

COVID-19: Acanthamoeba Creeps into the Brain

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