Acanthamoebae are the most common opportunistic amphizoic protozoa that cause life-threatening granulomatous amoebic encephalitis in immunocompromised individuals and sight-threatening amoebic keratitis (AK) in contact lens wearers. The present work aimed to determine the presence of Acanthamoeba isolates in different environmental sources: water, soil, and dust in Cairo, Egypt and to characterize the pathogenic potential of the isolated Acanthamoeba using physiological and biochemical assays as well as determination of the genotypes in an attempt to correlate pathogenicity with certain genotypes. The study included the collection of 22 corneal scrapings from patients complaining of symptoms and signs indicative of acanthamoeba keratitis (AK) and 75 environmental samples followed by cultivation on non-nutrient agar plates preseeded with E. coli. Positive samples for Acanthamoeba were subjected to osmo- and thermo-tolerance assays and zymography analysis. Potentially pathogenic isolates were subjected to PCR amplification using genus-specific primer pair. Isolates were classified at the genotype level based on the sequence analysis of Acanthamoeba 18S rRNA gene (diagnostic fragment 3). The total detection rate for Acanthamoeba in environmental samples was 33.3 %, 31.4 % in water, 40 % in soil, and 20 % in dust samples. Three and two Acanthamoeba isolates from water and soil sources, respectively, had the potential for pathogenicity as they exhibited full range of pathogenic traits. Other 12 isolates were designated as weak potential pathogens. Only ten of the environmental isolates were positive in PCR and were classified by genotype analysis into T4 genotype (70 %), T3 (10 %) and T5 (20 %). Potential pathogens belonged to genotypes T4 (from water) and T5 (from soil) while weak potential pathogens belonged to genotypes T3 (from water) and T4 (from water and soil). Additionally, T7 genotype was isolated from keratitis patients. There is a considerable variation in the response of Acanthamoeba members of the same genotype to pathogenicity indicator assays making correlation of pathogenicity with certain genotypes difficult. Presence of potentially pathogenic Acanthamoeba isolates in habitats related directly to human populations represent a risk for human health. Isolation of Acanthamoeba genotype T7 from AK cases, which is commonly considered as nonpathogenic, might draw the attention to other Acanthamoeba genotypes considered as non pathogenic and reevaluate their role in production of human infections. To our knowledge, this is the first study on the presence and distribution of Acanthamoeba genotypes in the environment, Cairo, Egypt.

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Cystic echinococcosis (CE) is usually asymptomatic, and commonly presents by pressure symptoms according to its location. Diagnosis of CE is currently based on imaging techniques, which may not be available in some areas and antibody detection in serum, with its known several drawbacks. Conversely, antigen detection has proven its efficacy in serodiagnosis of CE. The study evaluated the efficacy of Nanomagnetic beads (NMB)-sandwich ELISA for diagnosis of CE by detection of Echinococcus (E.) granulosus Antigen B (AgB) in serum and urine samples as compared with sandwich ELISA. A total of 42 individuals were classified into 3 groups; CE infection group, other parasitic infections group and control group. E. granulosus AgB was prepared from human hydatid cysts to produce anti-E. granulosus AgB-immunoglobulin (Ig) Gpoly-clonal Abs in rabbit, after purification, to detect AgB level in serum and urine samples by sandwich ELISA and NMB-sandwich ELISA. Using sandwich ELISA, AgB was detected in sera of CE patients with sensitivity and specificity of 88.9% & 91.7%, respectively. In urine samples, sandwich ELISA detected AgB in CE patients and the sensitivity and specificity were 83.3% and 87.5%, respectively. NMB-sandwich ELISA detected AgB in serum samples of CE patients with a sensitivity and specificity of 94.4% and 95.8%, respectively, whereas in urine samples it was detected in CE cases and the sensitivity and specificity were 88.9% and 95.8%, respectively, without significant statistical difference (p>0.05) between serum and urine samples for detection of AgB when examined by either sandwich ELISA or NMB-sandwich ELI-SA. The best accuracy was obtained with NMB-sandwich ELISA detecting AgB in serum samples (95.2%), with a slightly lower accuracy of 92.9% when using urine samples. NMBsandwich ELISA is efficient for detection of E. granulosus AgB in serum samples. Moreover, urine samples might be a good alternative to serum samples for the detection of AgB.