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Parasite Epidemiology and Control Aug 2023spp. is opportunistic amoeba that resides in water, soil, and air. Some pathogenic genotypes of the genus of can cause granulomatous amoebic encephalitis (GAE) in...
BACKGROUND
spp. is opportunistic amoeba that resides in water, soil, and air. Some pathogenic genotypes of the genus of can cause granulomatous amoebic encephalitis (GAE) in people with a defective immune system. The parasite can also cause keratitis (AK) among contact lens users. This study was conducted to isolate and identify the genotypes in water resources in Lorestan province, western Iran.
METHODS
Collected 72 water samples from surface and groundwater (springs and aqueducts) in Lorestan province. Samples were filtered and cultured in non-nutrient 1.5% agar medium covered with at 25 °C. DNA extraction was done and the PCR reaction was performed to detect the spp. The positive PCR products were sequenced to determine the genotypes of
RESULTS
Out of 72 examined water samples, 23.61% were positive for sp. by PCR. From PCR-positive samples, 8 (47.05%) samples were T4 genotypes and others were other genotypes (T1-T23). Therefore, approximately half of the genotypes belong to the pathogenic T4 genotype.
CONCLUSIONS
The water examined samples in western provinces of Iran have the potential risk factor for public health. Therefore, the efforts of healthcare providers are needed to identify, train, and prevention from human infections.
PubMed: 37638113
DOI: 10.1016/j.parepi.2023.e00308 -
Cornea Nov 2023The aim of this study was to analyze real-world practice patterns and graft survival after corneal transplantation for infectious keratitis in the Netherlands.
PURPOSE
The aim of this study was to analyze real-world practice patterns and graft survival after corneal transplantation for infectious keratitis in the Netherlands.
METHODS
All consecutive keratoplasties for infectious keratitis registered in the Netherlands Organ Transplant Registry were included. Graft survival was analyzed using Kaplan-Meier survival curves with Cox regression to compare the 3 most common pathogens with subgroup analysis for type and reason of transplantation, sex, and graft size. Multivariable analysis was performed using the same explanatory factors.
RESULTS
Between 2007 and 2017, 1111 keratoplasties for infectious keratitis were registered in the Netherlands Organ Transplant Registry. The most common pathogens were viruses (n = 437), bacteria (n = 271), and Acanthamoeba (n = 121). Human leukocyte antigen (HLA) matching did not provide a significant survival benefit, whereas emergency procedures showed worse graft survival [hazard ratio (HR) = 0.40, P = 0.120; HR = 2.73, P < 0.001, respectively]. Graft size >8.5 mm was significantly worse than graft size 8.5 mm (HR = 2.062, P = 0.010). In therapeutic keratoplasty, graft survival was significantly worse for Acanthamoeba than viral keratitis (HR = 2.36, P = 0.008). In the multivariable model, adjusting for graft size, type, and reason for transplantation, viral and bacterial keratitis did not differ significantly in graft survival, and Acanthamoeba showed a significantly worse prognosis (vs. viral keratitis, HR = 2.30, P < 0.001; bacterial keratitis, HR = 2.65, P < 0.001).
CONCLUSIONS
Viral keratitis was the most common indication for transplantation, followed by bacterial and Acanthamoeba keratitis. HLA matching did not offer protection over elective non-HLA-matched procedures, whereas emergency procedures and grafts sized >8.5 mm showed poor survival. In optical keratoplasty, survival is high for all pathogens, whereas in therapeutic keratoplasty Acanthamoeba shows poor outcome.
Topics: Humans; Prospective Studies; Keratoplasty, Penetrating; Treatment Outcome; Visual Acuity; Corneal Transplantation; Acanthamoeba Keratitis; Eye Infections, Viral; Registries; Graft Survival; Retrospective Studies
PubMed: 36737861
DOI: 10.1097/ICO.0000000000003218 -
Food Microbiology Sep 2024Acanthamoeba spp., are ubiquitous protist which belongs to Free-Living Amoeba (FLA) group, is considered as causal agent of side-threatening keratitis or fatal...
Acanthamoeba spp., are ubiquitous protist which belongs to Free-Living Amoeba (FLA) group, is considered as causal agent of side-threatening keratitis or fatal encephalitis among other human infections. Besides, this parasite has been reported as host for other microorganisms important to human health such as Campylobacter spp. or Vibrio spp. among others. This role of Acanthamoeba as pathogen and environmental phagocyte has increased the reports confirming its presence in human related environments, acting as a water quality indicator. Considering the tide relationship between water and kitchen environments, and the high prevalence of Acanthamoeba in water sources, the present study aims to establish a quick and accurate protocol based on DNA extraction and a real time qPCR assay to detect Acanthamoeba spp. in dishcloths. The procedure has been validated by processing 17 used dishcloths. Our findings demonstrated the high sensitivity of the qPCR assay used which was capable of detecting up to one Acanthamoeba from an in vitro contaminated dishcloth. The protocol accurately detected 64.7% of positive samples for Acanthamoeba spp, (in 4 samples DNA concentrations corresponded to 1-10 amoebae). Our findings demonstrate the importance of FLA surveillance by efficient and sensitive methods since one amoeba is capable of colonizing human related food environments such as kitchens sinks and could be a potential source of infection.
Topics: Acanthamoeba; Real-Time Polymerase Chain Reaction; DNA, Protozoan; Humans; Sensitivity and Specificity
PubMed: 38839225
DOI: 10.1016/j.fm.2024.104562 -
Veterinary World Apr 2024Keratitis is a serious ocular infection often caused by pathogenic microorganisms such as spp. Among other harmful microbes, keratitis presents a particular challenge...
BACKGROUND AND AIM
Keratitis is a serious ocular infection often caused by pathogenic microorganisms such as spp. Among other harmful microbes, keratitis presents a particular challenge due to its resistance to conventional antimicrobial agents. Linn., commonly known as betel leaf, has been traditionally used for its medicinal properties. This study aimed to assess the potential of the leaf ethanol extract of Linn. in the treatment of in monoculture and co-culture with two prevalent pathogenic bacteria, and , associated with keratitis.
MATERIALS AND METHODS
Minimum inhibitory concentrations (MICs) of , , and extracts in monoculture and coinfected conditions were examined. In addition, this study explored the potential of the extract in preventing adherence in both monoculture and co-culture environments. Scanning electron microscopy (SEM) analysis confirmed the impact of the extract on cell membranes, including acanthopodia. Furthermore, a time-kill kinetic assay was used to validate the amoebicidal activity of the extract against and the tested bacteria.
RESULTS
MICs for trophozoites, cysts, , and in the monoculture were 0.25, 0.25, 0.51, and 0.128 mg/mL, respectively, whereas the MICs for coinfected with bacteria were higher than those in the monoculture. This extract inhibited the growth of trophozoites and cysts for up to 72 h. Moreover, extract effectively prevented the adherence of to contact lenses under monoculture conditions. SEM analysis confirmed that extract affects the cell membrane of , including Acanthopodia. In addition, the time-kill kinetic assay confirmed that the extract contained amoebicidal activity against , including the tested bacteria. Notably, was more susceptible than and to extract treatment. Unexpectedly, our study revealed that negatively affected in the co-culture after 3 days of incubation, whereas facilitated the growth of in the presence of the extract.
CONCLUSION
This study provides compelling evidence of the anti-adhesive and anti- properties of leaf extract against under monoculture and co-culture conditions. The observed impact on cell membranes, coupled with the time-kill kinetic assay results, underscores the potential of leaf extract as a promising agent for combating -related infections in humans and animals.
PubMed: 38798284
DOI: 10.14202/vetworld.2024.848-862 -
Diagnostic Microbiology and Infectious... Oct 2023Acanthamoeba keratitis is a devastating infectious disease of the cornea caused by an opportunistic amoeba, Acanthamoeba castellanii. It is poorly recognized, and...
Acanthamoeba keratitis is a devastating infectious disease of the cornea caused by an opportunistic amoeba, Acanthamoeba castellanii. It is poorly recognized, and diagnostic delays can lead to irreversible damage to the vision. The gold standard for diagnosis has been a sample culture that lasts approximately 2 weeks. Nevertheless, the essence of time has led to the need for an accurate and fast technique to detect A. castellanii from a sample. We developed both traditional and quantitative real-time-PCR-based methods to detect A. castellanii in less than 3 hours and with the sensitivity of one amoeba. Diagnostic laboratories can select the best-suited method for their purposes from 2 comparable methods. The correct treatment can be initiated from the emergency room when the diagnosis has been made quickly within a few hours, hence saving the patient from long-term complications.
Topics: Humans; Acanthamoeba castellanii; Rapid Diagnostic Tests; Acanthamoeba Keratitis; Cornea; Real-Time Polymerase Chain Reaction
PubMed: 37506594
DOI: 10.1016/j.diagmicrobio.2023.116014 -
Parasites, Hosts and Diseases Feb 2024Acanthamoeba infection is associated with keratitis in humans; however, its association with keratitis in dogs remains unclear. To investigate this possibility, we...
Acanthamoeba infection is associated with keratitis in humans; however, its association with keratitis in dogs remains unclear. To investigate this possibility, we collected 171 conjunctival swab samples from dogs with eye-related diseases (65 with keratitis and 106 without keratitis) at Chungbuk National University Veterinary Teaching Hospital, Korea, from August 2021 to September 2022. Polymerase chain reaction identified 9 samples (5.3%) as Acanthamoeba positive; of these, 3 were from dogs with keratitis (4.6%) and 6 were from dogs without keratitis (5.7%). Our results indicated no significant association between Acanthamoeba infection and keratitis, season, sex, or age. All Acanthamoeba organisms found in this study had the genotype T4, according to 18S ribosomal RNA analysis. Acanthamoeba infection in dogs might have only a limited association with keratitis.
Topics: Humans; Dogs; Animals; Hospitals, Animal; Hospitals, Teaching; Amebiasis; Keratitis; Acanthamoeba; Republic of Korea
PubMed: 38443777
DOI: 10.3347/PHD.23112 -
Graefe's Archive For Clinical and... Jul 2023Acanthamoeba keratitis (AK) is a painful and possibly sight-threatening ocular infection. While the correct diagnosis and specific treatment in the early stages...
PURPOSE
Acanthamoeba keratitis (AK) is a painful and possibly sight-threatening ocular infection. While the correct diagnosis and specific treatment in the early stages significantly improve the prognosis, the disease is often misdiagnosed and in clinical examination confused with other forms of keratitis. Polymerase chain reaction (PCR) for the detection of AK was first introduced in our institution in December 2013 to improve the timely diagnosis of AK. The aim of this study was to assess the impact of implementation of Acanthamoeba PCR on the diagnosis and treatment of the disease in a German tertiary referral center.
PATIENTS AND METHODS
Patients treated for Acanthamoeba keratitis between 1st of January 1993 and 31st of December 2021 in the Department of Ophthalmology of the University Hospital Duesseldorf were identified retrospectively via in-house registries. Evaluated parameters include age, sex, initial diagnosis, method of correct diagnosis, duration of symptoms until correct diagnosis, contact lens use, visual acuity, and clinical findings as well as medical and surgical therapy by keratoplasty (pKP). In order to assess the impact of implementation of Acanthamoeba PCR, the cases were divided into two groups (before (pre-PCR group) and after PCR implementation (PCR group).
RESULTS
Seventy-five patients with Acanthamoeba keratitis were included (69.3% female, median age 37 years). Eighty-four percent (63/75) of all patients were contact lens wearers. Until PCR was available, 58 patients with Acanthamoeba keratitis were diagnosed either clinically (n = 28), by histology (n = 21), culture (n = 6), or confocal microscopy (n = 2) with a median duration until diagnosis of 68 (18; 109) days. After PCR implementation, in 17 patients, the diagnosis was established with PCR in 94% (n = 16) and median duration until diagnosis was significantly shorter with 15 (10; 30.5) days. A longer duration until correct diagnosis correlated with a worse initial visual acuity (p = 0.0019, r = 0.363). The number of pKP performed was significantly lower in the PCR group (5/17; 29.4%) than in the pre-PCR group (35/58; 60.3%) (p = 0.025).
CONCLUSIONS
The choice of diagnostic method and especially the application of PCR have a significant impact on the time to diagnosis and on the clinical findings at the time of confirmation of diagnosis and the need for penetrating keratoplasty. In contact lens-associated keratitis, the first crucial step is to take AK into consideration and perform a PCR test as timely confirmation of diagnosis of AK is imperative to prevent long-term ocular morbidity.
Topics: Humans; Female; Adult; Male; Acanthamoeba Keratitis; Retrospective Studies; Acanthamoeba; Polymerase Chain Reaction; Disease Progression
PubMed: 36795161
DOI: 10.1007/s00417-023-05993-7 -
Arquivos Brasileiros de Oftalmologia 2023To study epidemiological data, laboratory results, and risk factors associated with microbial keratitis. (Review)
Review
PURPOSE
To study epidemiological data, laboratory results, and risk factors associated with microbial keratitis.
METHODS
We conducted a retrospective study of corneal sample cultures from patients with microbial keratitis from January 2010 to December 2019. Results were analyzed according to the etiological diagnosis of bacterial, mycotic, or parasitic infection and were associated with related risk factors.
RESULTS
We analyzed 4810 corneal samples from 4047 patients (mean age 47.79 ± 20.68 years; male 53.27%). The prevalence of bacterial, fungal, and Acanthamoeba infections were 69.80%, 7.31%, and 3.51%, respectively. The most frequently isolated bacteria were coagulase-negative Staphylococcus (CoNS) (45.14%), S. aureus (10.02%), Pseudomonas spp. (8.80%), and Corynebacterium spp. (6.21%). Among CoNS, the main agent was S. epidermidis (n=665). For mycotic keratitis, Fusarium spp. (35.42%) and Candida parapsilosis (16.07%) were the most common agents among filamentous and yeasts isolates, respectively. Contact lens use was associated with a positive culture for Acanthamoeba spp. (OR = 19.04; p < 0.001) and Pseudomonas spp. (OR = 3.20; p < 0.001). Previous ocular trauma was associated with positive fungal cultures (OR = 1.80; p = 0.007), while older age was associated with positive bacterial culture (OR = 1.76; p = 0.001).
CONCLUSIONS
Our findings demonstrated a higher positivity of corneal sample cultures for bacteria. Among those, CoNS was the most frequently identified, with S. epidermidis as the main agent. In fungal keratitis, Fusarium spp. was the most commonly isolated. Contact lens wearers had higher risks of positive cultures for Acanthamoeba spp. and Pseudomonas spp. Ocular trauma increased the risk of fungal infection, while older age increased the risk of bacterial infection.
Topics: Adult; Aged; Humans; Male; Middle Aged; Bacteria; Brazil; Corneal Ulcer; Eye Infections, Bacterial; Eye Infections, Fungal; Fusarium; Keratitis; Retrospective Studies; Risk Factors; Staphylococcus aureus; Female
PubMed: 37878874
DOI: 10.5935/0004-2749.2022-0060 -
Turkiye Parazitolojii Dergisi Mar 2024The aim of this study was to evaluate the pathogenicity of strains with T4, T5, T11, and T12 genotypes by comparing the osmotolerance and thermotolerance...
OBJECTIVE
The aim of this study was to evaluate the pathogenicity of strains with T4, T5, T11, and T12 genotypes by comparing the osmotolerance and thermotolerance characteristics of strains isolated from genotype groups, within species with the same genotype, and from environmental and keratitis cases.
METHODS
In this study, after axenic cultures of 22 strains with T4 (Neff, A, B, D, E), T5, T11, and T12 genotypes isolated from clinical and environmental samples, thermotolerance (37 °C, 39 °C and 41 °C) and osmotolerance (0.5 M, 1 M) tests were performed.
RESULTS
All strains showed growth ability at 37 °C and 0.5 M osmolarity. While all five strains isolated from patients with keratitis showed growth ability at 37 °C and 0.5 M osmolarity, no growth was detected at 41 °C and 1 M osmolarity. When the tolerance characteristics of the strains with the same genotype were evaluated, the strains with the T5 and T4E genotypes showed the same characteristics. When strains with the T4 genotype were evaluated in general, 31.25% of the strains were found to grow at 39 °C and 6.25% at 41 °C. Of the T4Neff strains, only one strain did not show the ability to reproduce at 39 °C and showed a different feature from the other strains. While the strain with the T11 genotype grew at all temperatures, the strain with the T12 genotype did not grow at 41 °C.
CONCLUSION
According to our research results, we believe that tolerance to 39 °C and 1 M mannitol is not an indicator of pathogenicity. More studies with strains are required to clarify this issue.
Topics: Humans; Acanthamoeba; Virulence; Thermotolerance; Genotype; Mannitol
PubMed: 38449362
DOI: 10.4274/tpd.galenos.2024.92408 -
Microorganisms Mar 2024The genus comprises free-living amoebae distributed in a wide variety of environments. These amoebae are clinically significant, causing opportunistic infections in...
The genus comprises free-living amoebae distributed in a wide variety of environments. These amoebae are clinically significant, causing opportunistic infections in humans and other animals. Despite this, limited data on sequence types and alleles are available in Italy. In the present study, we analyzed all sequences deposited from Italy with new positive clinical samples from symptomatic AK cases, to provide an overview of the genetic variants' spatial patterns from different sources within the Italian context. A total of 137 sequences were obtained. Six sequence types were identified: T2/6, T3, T4, T11, T13, and T15. Only T4 and T15 were found in both sources. The T4 sequence type was found to be the most prevalent in all regions, accounting for 73% (100/137) of the Italian samples analyzed. The T4 sequence type demonstrated significant allelic diversity, with 30 distinct alleles from clinical and/or environmental samples. These outcomes enabled a better understanding of the distribution of isolates throughout Italy, reaffirming its well-recognized ubiquity. isolates analysis from keratitis, together with the environmental strains monitoring, might provide important information on different genotypes spreading. This might be useful to define the transmission pathways of human keratitis across different epidemiological scales.
PubMed: 38543595
DOI: 10.3390/microorganisms12030544