Amoebicidal effect of Allium cepa against Allovahlkampfia spelaea: A keratitis model.

Allovahlkampfia spelaea (A. spelaea) is a free-living amoeba, proved to cause Acanthamoeba-like keratitis with quite difficult treatment. This study aimed to evaluate the amoebicidal effect of Allium cepa (A. cepa) on A. spelaea trophozoites and cysts both in vitro and in vivo using Chinchilla rabbits as an experimental model of this type of keratitis. Chemical constituents of the aqueous extract of A. cepa were identified using Liquid Chromatography-mass Spectrometry (LC-MS). In vitro, A. cepa showed a significant inhibitory effect on trophozoites and cysts compared to the reference drug, chlorhexidine (CHX) as well as the non-treated control (P < 0.05) with statistically different effectiveness in terms of treatment durations and concentrations. No cytotoxic effect of A. cepa on corneal cell line was found even at high concentrations (32 mg/ml) using agar diffusion method. The in vivo results confirmed the efficacy of A. cepa where the extract enhanced keratitis healing with complete resolution of corneal ulcers in 80% of the infected animals by day 14 (post infection)pi compared to 70% recovery with CHX after 20 treatment days. The therapeutic effect was also approved at histological, immune-histochemical, and parasitological levels. Our findings support the potential use of A. cepa as an effective agent against A. spelaea keratitis.

Green biosynthesis of silver nanoparticles by Aspergillus niger and its antiamoebic effect against Allovahlkampfia spelaea trophozoite and cyst.

BACKGROUND: Fungi represent an interesting candidate for the synthesis of nanoparticles. The biosynthesis of silver nanoparticles (AgNPs) has many industrial and biomedical indications. We aimed in this work to biologically synthesize silver nanoparticles using Aspergillus niger and to evaluate its effect against the newly identified Allovahlkampfia spelaea that causes resistant human keratitis. MATERIAL AND METHODS: Aspergillus niger (soil isolate) was treated with silver nitrate to produce silver nanoparticles. AgNPs were characterized by Ultraviolet-Visible Spectroscopy, Transmission Electron Microscopy, and Fourier Transform Infrared Spectroscopy. The effect of the synthesized nanoparticles against Allovahlkampfia spelaea growth, encystation, excystation, and toxicity in host cells was evaluated. RESULTS: AgNPs exhibited significant inhibition of Allovahlkampfia spelaea viability and growth of both trophozoites and cysts, with a reduction of amoebic cytotoxic activity in host cells. CONCLUSION: AgNPs may give a promising future to the treatment of Allovahlkampfia spelaea infections in humans.

The Effects of Commercially Available Syzygium aromaticum, Anethum graveolens, Lactobacillus acidophilus LB, and Zinc as Alternatives Therapy in Experimental Mice Challenged with Cryptosporidium parvum.

BACKGROUND: Waterborne cryptosporidiosis is the second cause of diarrhea in young children and immunocompromised hosts after rotavirus. Except for nitazoxanide (NTZ), there is no accredited cryptosporidiosis treatment to date. Therefore, there is an urgent need to find an effective and safe treatment for cryptosporidiosis. This study aimed to investigate the possible anti-protozoal effects of Syzygium aromaticum (clove) oil, Anethum graveolens (dill) seeds oil, Lactobacillus acidophilus LB, and zinc against Cryptosporidium parvum in comparison to NTZ. METHODS: Besides the negative control, mice from six experimental groups (T1-T6) were infected with Cryptosporidium parvum oocysts. On the seventh day post-infection (PID), mice from five groups were treated for 8 consecutive days with NTZ, clove oil, dill seed oil, Lactobacillus acidophilus LB, and zinc commercial forms (T2-T5). Oocysts shedding rate, differences of mice body weight, serum IL10, and TNF-α, cryptosporidial antigen, and cd3 at the intestinal mucosa were evaluated at the end of the experiment. RESULTS: The mean of the C. parvum oocysts' shedding rate was significantly lower in all treated groups than in the non-treated group. The oocysts reduction rate was the highest in zinc-treated mice (98.3%), Lactobacillus acidophilus LB and dill-treated groups (95.77%), and the NTZ-treated group (91.55%). Clove oil was the least effective, with a 74.65% reduction rate. Excluding the clove oil-treated group, immunohistochemical analysis revealed the clearance of the Cryptosporidium antigen in the intestinal tissue in all treated groups. CONCLUSION: The study has provided a rational basis for using these safe, cheap, and commercially available alternatives in treating cryptosporidiosis combined with NTZ.

Isolation and morphological and molecular characterization of waterborne free-living amoebae: Evidence of potentially pathogenic Acanthamoeba and Vahlkampfiidae in Assiut, Upper Egypt.

Free-living amoebae (FLA) are gaining attention due to the increasing number of related grave central nervous system (CNS) and sight-threatening eye infections and their role as Trojan horses for many bacteria and viruses. This study was conducted in Assiut City, Egypt to detect the presence of FLA in different water sources using morphological and molecular approaches and determine their potential pathogenicity. A total of 188 water samples (100 tap, 80 tank, and 8 swimming pool samples) were collected, cultivated on non-nutrient agar seeded with Escherichia coli, and inspected for FLA. Thermo- and osmo-tolerance assays were performed to determine their pathogenicity. Polymerase chain reaction and sequence analysis were performed to confirm the identification and analyze the genotype. Overall, 52 samples (27.7%) were positive for FLA. Of these, 20.7% were identified as Acanthamoeba, 1.6% as Vahlkampfiidae, and 5.3% as mixed Acanthamoeba and Vahlkampfiidae. Seven species of Acanthamoeba were recognized, of which A. triangularis, A. polyphaga, A. lenticulata, and A. culbertsoni are thermo- and osmo-tolerant, and A. astronyxis, A. comandoni, and A. echinulata are non-thermo- and non-osmo-tolerant. The phylogeny analysis revealed T4 and T7 genotypes. Among Vahlkampfiids, 61.5% were identified as thermo- and osmo-tolerant Vahlkampfia, and 30.8% were identified as non-pathogenic Naegleria. One isolate (7.7%) was identified as potentially pathogenic Allovahlkampfia, as confirmed by sequencing. This is the first report documenting the occurrence and phylogeny of waterborne FLA (Acanthamoeba/Vahlkampfiidae) in Assiut, Egypt. The presence of potentially pathogenic FLA highlights the possible health hazards and the need for preventive measures.

Ganoderma lucidum extract inhibits Schistosoma mansoni survival in silico and in vitro study.

Schistosomosis is a worldwide tropical disease primarily caused by Schistosoma mansoni. Praziquantel is the only available drug for controlling schistosomosis, with many challenges. This study aims to evaluate the in vitro anti-Schistosoma effect of Ganoderma lucidum (G. lucidum) against adult and larval stages of Schistosoma based on the prediction of the binding activity of G. lucidum protein with proteins of various stages of S. mansoni by molecular docking to confirm its inhibitory potential through an insilico study. Results showed that Leu143, Ser165, Met214, and Asn213 were the primary crucial amino acids involved in the binding, with a promising large area of interactions between the two studied proteins. The in vitro study evaluated the motility and survival of adult and larval stages, compared to praziquantel and niclosamide, respectively. There was a significant reduction in the motility of adults after the two-hour incubation, with all concentrations and 100% death of all parasites with the minimal concentration (10 µg/ml) within 4 and 6 h of incubation (P<0.01). Regarding the cercariae, at a concentration of 10 µg/ml, all the cercariae (100%) died (P<0.01) after 15 min, and the miracidial complete mortality rate (100%) (P<0.01) occurred at a concentration of 10 µg/ml after 8 min. This study first predicted the binding activity of G. lucidum protein with proteins of S. mansoni at various stages and proved the anti-Schistosoma effect of G. lucidum in vitro, considered a promising treatment for schistosomosis.

Thymus vulgaris, Mentha piperita and Elettaria cardamomum against Trypanosoma evansi in vitro and in an animal model with new insights for the treatment of trypanosomosis.

Trypanosomosis is a worldwide disease that affects human and livestock populations with limited availability and high cost of trypanocides. The study aims to evaluate the possible in vitro and in vivo anti-trypanosomal activity of Thymus vulgaris (thyme), Mentha piperita (mint) and Elettaria cardamomum (cardamom) aqueous extracts against Trypanosoma evansi in experimentally infected rats using Intropar as a reference drug. The crude extracts of the selected plants were used in three concentrations (2500, 2000, and 1000 µg/ml). The in vitro trypanocidal activities were assessed regarding parasite motility, count, and infectivity. The in vivo susceptibility of T. evansi was evaluated by assessing the level of parasitemia in the experimental rats. The packed cell volume (PCV) was also monitored. Both the in vitro and in vivo experiments showed trypanocidal activity, of all the tested extracts, higher than that of Intropar. The in vitro trypanocidal effects were dose-dependent and represented by a significant reduction of the parasite count together with immobilizing effect within 3 hours incubation period, compared to the negative and positive controls (p< 0.05). The in vivo trypanocidal effects of the different concentrations of all the tested extracts were represented by the significantly lowered levels of parasitemia, compared to the negative control (NC) group with varying degrees; in a dose-dependent manner concerning the time. They exhibited also a significantly higher level in PCV recovery compared to the NC group (p < 0.05). This study initially confirmed the potent in vitro and in vivo trypanocidal effect of the three extracts, with a potentially promising future for the treatment of trypanosomosis.

The protective effect of Lactobacillus acidophilus on experimental animals challenged with Trichinella spiralis; new insights on their feasibility as prophylaxis in Trichinella spiralis endemic area.

Trichinellosis is a common parasitic zoonosis. Complications of anthelmintic drugs combined with steroids raise the urge of alternative protective ways. The study aimed to investigate the protective effects of Lactobacillus acidophilus probiotic on both Trichinella spiralis adults and larvae in experimental animal models. Thirty-six male BALB/c mice were divided into 3 groups: negative control Group (G I); Group (G II) mice were inoculated orally by 500 Trichinella spiralis larvae; tested Group (G III) mice were prophylactic by an oral dose of Lactobacillus acidophilus in commercially available form for seven consecutive days, before infection. Mature worms and encysted larvae were counted on the 5th and 21st day post-infection (dpi), respectively. IL-1, IL-6, IL-10 and TNF-α concentrations were estimated at 5th and 21st dpi of all groups. Significant reductions in mean worms and larvae burden were detected by 62.1% and 73.5% in the prophylactic group compared to the non-prophylactic group. The cytokine profiles were revealed IL-1 and IL-6 up-regulation compared to IL-10 and TNF-α down-regulation in the tested group compared to other groups. Although Lactobacillus acidophilus failed to achieve complete eradication of Trichinella spiralis adults and larvae, it showed powerful effects in reducing parasites and cytokines burdens.

Allovahlkampfia spelaea Causing Keratitis in Humans.

BACKGROUND: Free-living amoebae are present worldwide. They can survive in different environment causing human diseases in some instances. Acanthamoeba sp. is known for causing sight-threatening keratitis in humans. Free-living amoeba keratitis is more common in developing countries. Amoebae of family Vahlkampfiidae are rarely reported to cause such affections. A new genus, Allovahlkampfia spelaea was recently identified from caves with no data about pathogenicity in humans. We tried to identify the causative free-living amoeba in a case of keratitis in an Egyptian patient using morphological and molecular techniques. METHODS: Pathogenic amoebae were culture using monoxenic culture system. Identification through morphological features and 18S ribosomal RNA subunit DNA amplification and sequencing was done. Pathogenicity to laboratory rabbits and ability to produce keratitis were assessed experimentally. RESULTS: Allovahlkampfia spelaea was identified as a cause of human keratitis. Whole sequence of 18S ribosomal subunit DNA was sequenced and assembled. The Egyptian strain was closely related to SK1 strain isolated in Slovenia. The ability to induce keratitis was confirmed using animal model. CONCLUSIONS: This the first time to report Allovahlkampfia spelaea as a human pathogen. Combining both molecular and morphological identification is critical to correctly diagnose amoebae causing keratitis in humans. Use of different pairs of primers and sequencing amplified DNA is needed to prevent misdiagnosis.