Axenic cultivation and pathogenic assays of acanthamoeba strains using physical parameters

The main goal of the present study was to set up an axenic cultivation of Acanthamoeba and assess the pathogenic ability of T4 genotypes from different clinical and environmental strains of Acanthamoeba using two physical assays. Sixteen Acanthamoeba isolates including 10 environmental and 6 clinical strains were cultured axenically. Axenic cultivation was performed using Proteosepepton, yeast extract and glucose medium and TY-I-S33culture. Pathogenic survey was done using osmotolerance and thermotolerance assay. Briefly, differentosmolarity [0.5 M and 1 M] of non-nutrient agar plates were performed. One hundred fiftymicrol of axenic culture were collected and were inoculated in 1% agar medium. For thermotolerance assay 150 micro L of amoebas from axenic culture were divided into fresh culture mediums. Cultures were incubated at 37degreeC and 42degreeC. All plates were monitored for 24 h, 48 h and 72 h. Overall, 16 strains of Acanthamoeba isolates previously genotyped as T4 were cultivated axenically after several months. Thermotolerance and osmotolerance assay revealed that all of clinical strains, soil and animal feces strains were highly pathogenic isolates. Two dust and water strains did not grow at high temperature [42degreeC] and osmolarity [1.5 M] and thus they were classified as weak pathogens. Most of T4 genotypes are highly pathogenic organisms. This is an important finding since Acanthamoeba belonging to T4 type is the predominate genotype in environmental and clinical samples. The presence of highly pathogenic Acanthamoeba may pose a risk within susceptible people.

Cryptosporidium spp. infection in human and domestic animals

Cryptosporidium spp. is a coccidian parasite infected humans and animals. Prevalence rate of Cryptosporidium spp. infection associated with is some parameters such as sampling, age, season, country and contact to domestic animals. This study aimed to determine Cryptosporidium spp. Infection in humans and some animals in rural areas of Shushtar district from Khuzestan Province, south- west of Iran. In this study, Stool specimens were randomly collected from 45 cattle, 8 buffalos, 35 calves, 22 turkeys, 3 sheep, 2 geese as well as 62 humans in different seasons selected from rural areas of Shushtar district located in Khuzestan in the south- west of Iran from August 2009 to April 2011. The collected stool samples were examined by modified Ziehl-Neelsen staining method. Altogether, 68/115 [59.1%] domestic animals and 9/62 [14.5%] of humans were showed Cryptosporidium spp. infection in the study areas. In this study we found the high frequency of Cryptosporidium spp. infection in the studied areas

Amoebic keratitis in Iran [1997-2007]

Amoebic keratitis introduced as a painful corneal infection which sometimes lead to poor vision and blindness. The main goal of this study was to report amoebic keratitis during ten years from 1997-2007 in patients who was suspected to have amoebic keratitis and referred to Parasitology laboratory, School of Public Health, Tehran University of Medical Sciences, Iran. Other aim was to assess the major risk factor for developing this sight-threatening disease. Comparison of lens culture and corneal scrapes culture also was performed. During 1997-2007, 142 patients referred to Dept. of Medical Parasitology, School of Public Health, Tehran University of Medical Sciences, Iran. Details of each patient such as age, sex, history of contact lens wear, type of contact lens, clinical symptoms were recorded in questioners. Keratitis was diagnosed on the basis of culture of lenses and/or corneal scrapes on non-nutrient agar overlaid with Escherichia coli and direct microscopy of lenses and/or corneal scrapes. Among 142 patients, 49 [34.5%] had amoebic keratitis. 73.46% of these patients were from Tehran but there were a few cases from other cities. The commonest age was between 15-25 yr [75.5%] and more female [37:12] were identified then male. It is worth to mention that 44 patients [89.79%] were contact lens wearers who among them 41 patients [93.18%] wore soft contact lens and only three patients suffer from amoebic keratitis because of wearing hard contact lens. Other finding of this study demonstrated that the most common sign of the patients was severe pain combined with photophobia. This study indicates that Acanthamoeba keratitis continue to rise in Iran. This is due to increase frequency of lens wearers as well as consideration of ophthalmologist to Acanthamoeba as an agent of keratitis and improvement of laboratory methods. Another finding of this research was the confirmation of soft contact lens as a major risk factor. It is recommended to educate contact lens wearers for regular disinfection. Besides, culture of corneal scrapes was negative in most of cases, so lens culture were performed which had a much better result

Contact lens-associated acanthamoeba keratitis in Iran

Acanthamoeba keratitis is a vision-threatening infection caused by pathogenic species of the genus Acanthamoeba. In this study, 13 Acanthamoeba keratitis cases were diagnosed among 52 keratitis patients. To confirm the identity of Acanthamoeba at the genus level, a PCR-based method was used, and their pathogenic potential was determined using in vitro cytotoxicity assays on human corneal epithelial cells. Twelve [92.3%] of Acanthamoeba keratitis patients were contact lens wearers; among them eleven [91.7%] wore soft contact lenses. 11/13 [84.6%] isolates were axenised in liquid culture medium, of which 10 [90.9%] isolates disrupted corneal cells. Nine [69.2%] isolates showed Acanthamoeba sp. group II, and four [30.8%] showed group III morphology. To our knowledge this is the first report of determination of Acanthamoeba pathogenicity in Iran. This study confirms the importance of determination of pathogenic potential of Acanthamoeba isolates for clinical purposes