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Journal of Water and Health Aug 2021The occurrence of potentially pathogenic free-living amoebae (FLA) in natural hot springs is considered a public health concern. FLAs are known to cause serious health...
The occurrence of potentially pathogenic free-living amoebae (FLA) in natural hot springs is considered a public health concern. FLAs are known to cause serious health outcomes to a wide spectrum of mammalian hosts. The present study aimed to provide the distribution of isolated cases of FLAs in hot springs through a systematic review process of available published articles online. Relevant studies are published between January 2010 and January 2020 involving the isolation of Naegleria spp., Acanthamoeba spp., Balamuthia spp., Sappinia spp., and Vermamoeba spp. in natural hot springs in the United States, South America, North America, Europe, Asia, and Africa. Articles were identified through a search of PubMed and Google Scholar databases. Out of 94 articles screened, a total of 20 articles are included in the study with consideration of established inclusion and exclusion criteria. The most common FLAs isolated in hot springs are Acanthamoeba spp. (134; 48.5%) and Naegleria spp. (127; 46.0%). Other FLAs isolated in hot springs include Balamuthia spp. (2; 0.7%) and Vermamoeba spp. (13; 4.7%). FLA in hot springs used for recreational and medical purposes is a potential source of infection. It is recommended that strict surveillance and maintenance of hot springs be implemented to prevent potential future infection.
Topics: Acanthamoeba; Amoeba; Animals; Hot Springs; Humans; Naegleria; Prevalence
PubMed: 34371494
DOI: 10.2166/wh.2021.101 -
Parasitology Research Sep 2021Acanthamoeba spp. are among the most worldwide prevalent protozoa. It is the causative agent of a disease known as Acanthamoeba keratitis, a painful and severe... (Review)
Review
Acanthamoeba spp. are among the most worldwide prevalent protozoa. It is the causative agent of a disease known as Acanthamoeba keratitis, a painful and severe sight-threatening corneal infection that can lead to blindness. In recent years, the prevalence of Acanthamoeba keratitis has rapidly increased, growing its importance to human health. This systematic review aims to assess the distribution of Acanthamoeba sp. genotypes causing keratitis around the world, considering the sample collected type and the used identification method. Most of the cases were found in Asia and Europe. Not surprisingly, the T4 genotype was the most prevalent worldwide, followed by T3, T15, T11, and T5. Furthermore, the T4 genotype contains a higher number of species. Given the differences in pathology, susceptibility to treatment, and clinical outcome between distinct genotypes, it is essential to genotype isolates from Acanthamoeba keratitis cases to help to establish a better correlation between in vitro and in vivo activities, resulting in better drug therapies and successful treatment in cases of this important ocular infection.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Cornea; Genotype; Humans
PubMed: 34351492
DOI: 10.1007/s00436-021-07261-1 -
Parasitology Research Aug 2021Acanthamoeba spp. have always caused disease in immunosuppressed patients, but since 1986, they have become a worldwide public health issue by causing infection in... (Review)
Review
Acanthamoeba spp. have always caused disease in immunosuppressed patients, but since 1986, they have become a worldwide public health issue by causing infection in healthy contact lens wearers. Amoebae of the Acanthamoeba genus are broadly distributed in nature, living either freely or as parasites, and are frequently associated with biofilms throughout the environment. These biofilms provide the parasite with protection against external aggression, thus favoring its increased pathogeny. This review aims to assess observational studies on the association between Acanthamoeba spp. and biofilms, opening potential lines of research on this severe ocular infection. A systematic literature search was conducted in May 2020 in the following databases: PubMed Central/Medline, LILACS, The Cochrane Library, and EMBASE. The studies were selected following the inclusion and exclusion criteria specifically defined for this review. Electronic research recovered 353 publications in the literature. However, none of the studies met the inclusion criterion of biofilm-producing Acanthamoeba spp., inferring that the parasite does not produce biofilms. Nonetheless, 78 studies were classified as potentially included regarding any association of Acanthamoeba spp. and biofilms. These studies were allocated across six different locations (hospital, aquatic, ophthalmic and dental environments, biofilms produced by bacteria, and other places). Acanthamoeba species use biofilms produced by other microorganisms for their benefit, in addition to them providing protection to and facilitating the dissemination of pathogens residing in them.
Topics: Acanthamoeba; Bacteria; Biofilms; Contact Lenses; Hospitals; Humans; Observational Studies as Topic
PubMed: 34292376
DOI: 10.1007/s00436-021-07240-6 -
Scientific Reports Jun 2021Infectious keratitis (IK) is the 5th leading cause of blindness globally. Broad-spectrum topical antimicrobial treatment is the current mainstay of treatment for IK,... (Meta-Analysis)
Meta-Analysis
Infectious keratitis (IK) is the 5th leading cause of blindness globally. Broad-spectrum topical antimicrobial treatment is the current mainstay of treatment for IK, though adjuvant treatment or surgeries are often required in refractory cases of IK. This systematic review aimed to examine the effectiveness and safety of adjuvant amniotic membrane transplantation (AMT) for treating IK. Electronic databases, including MEDLINE, EMBASE and Cochrane Central, were searched for relevant articles. All clinical studies, including randomized controlled trials (RCTs), non-randomized controlled studies and case series (n > 5), were included. Primary outcome measure was time to complete corneal healing and secondary outcome measures included corrected-distance-visual-acuity (CDVA), uncorrected-distance-visual-acuity (UDVA), corneal vascularization and adverse events. A total of twenty-eight studies (including four RCTs) with 861 eyes were included. When compared to standard antimicrobial treatment alone, adjuvant AMT resulted in shorter mean time to complete corneal healing (- 4.08 days; 95% CI - 6.27 to - 1.88; p < 0.001) and better UDVA (- 0.26 logMAR; - 0.50 to - 0.02; p = 0.04) at 1 month follow-up in moderate-to-severe bacterial and fungal keratitis, with no significant difference in the risk of adverse events (risk ratio 0.80; 0.46-1.38; p = 0.42). One RCT demonstrated that adjuvant AMT resulted in better CDVA and less corneal vascularization at 6 months follow-up (both p < 0.001). None of the RCTs examined the use of adjuvant AMT in herpetic or Acanthamoeba keratitis, though the benefit was supported by a number of case series. In conclusion, AMT serves as a useful adjuvant therapy in improving corneal healing and visual outcome in bacterial and fungal keratitis (low-quality evidence). Further adequately powered, high-quality RCTs are required to ascertain its therapeutic potential, particularly for herpetic and Acanthamoeba keratitis. Future standardization of the core outcome set in IK-related trials would be invaluable.
Topics: Amnion; Animals; Disease Management; Disease Susceptibility; Humans; Keratitis; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 34155280
DOI: 10.1038/s41598-021-92366-x -
Expert Review of Anti-infective Therapy Nov 2021: encompasses several species of free-living ameba encountered commonly throughout the environment. Unfortunately, these species of ameba can cause opportunistic...
: encompasses several species of free-living ameba encountered commonly throughout the environment. Unfortunately, these species of ameba can cause opportunistic infections that result in keratitis, granulomatous amebic encephalitis, and occasionally systemic infection.: This review discusses relevant literature found through PubMed and Google scholar published as of January 2021. The review summarizes current common keratitis treatments, drug discovery methodologies available for screening potential anti- compounds, and the anti- activity of various azole antifungal agents.: While several biguanide and diamidine antimicrobial agents are available to clinicians to effectively treat keratitis, no singular treatment can effectively treat every keratitis case.Efforts to identify new anti-Acanthamoeba agents include trophozoite cell viability assays, which are amenable to high-throughput screening. Cysticidal assays remain largely manual and would benefit from further automation development. Additionally, the existing literature on the effectiveness of various azole antifungal agents for treating keratitis is incomplete or contradictory, suggesting the need for a systematic review of all azoles against different pathogenic strains.
Topics: Acanthamoeba; Acanthamoeba Keratitis; Amebicides; Azoles; Drug Evaluation, Preclinical; Humans
PubMed: 33929276
DOI: 10.1080/14787210.2021.1924673 -
The Journal of International Medical... Mar 2021keratitis (AK) is a rare but severe ocular infection with a significant risk of vision loss. Contact lens use is the main risk factor for AK. The orthokeratology (OK)...
keratitis (AK) is a rare but severe ocular infection with a significant risk of vision loss. Contact lens use is the main risk factor for AK. The orthokeratology (OK) lens, a specially designed contact lens, has been used worldwide as an effective method of myopia control. However, the OK lens is associated with an increased risk of infection. Many primary practitioners are concerned about this infection because of its relative rarity, the lack of promising therapeutic medications, and the need for referral. We herein report two cases of AK associated with OK lenses, present a systematic review of such cases, and discuss the possible reasons for the higher incidence rate of this infection in patients who wear OK lenses. We combined the clinical knowledge and skills of corneal specialists and lens experts with the sole objective of addressing these OK lens-related AK cases. We found that the most common risk factors were rinsing the lenses or lens cases with tap water. Prompt and accurate diagnosis along with adequate amoebicidal treatment are essential to ensure desirable outcomes for OK lens wearers who develop AK. Appropriate OK lens parameters and regular checkups are also important.
Topics: Acanthamoeba Keratitis; Contact Lenses; Cornea; Humans; Myopia; Risk Factors
PubMed: 33752507
DOI: 10.1177/03000605211000985 -
Pathogens (Basel, Switzerland) Feb 2021, an opportunistic pathogen is known to cause an infection of the cornea, central nervous system, and skin. feeds different microorganisms, including potentially... (Review)
Review
, an opportunistic pathogen is known to cause an infection of the cornea, central nervous system, and skin. feeds different microorganisms, including potentially pathogenic prokaryotes; some of microbes have developed ways of surviving intracellularly and this may mean that acts as incubator of important pathogens. A systematic review of the literature was performed in order to capture a comprehensive picture of the variety of microbial species identified within following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Forty-three studies met the inclusion criteria, 26 studies (60.5%) examined environmental samples, eight (18.6%) studies examined clinical specimens, and another nine (20.9%) studies analysed both types of samples. Polymerase chain reaction (PCR) followed by gene sequencing was the most common technique used to identify the intracellular microorganisms. Important pathogenic bacteria, such as , spp. and were observed in clinical isolates of , whereas , adenovirus, mimivirus, and unidentified bacteria () were often identified in environmental . Increasing resistance of associated intracellular pathogens to antimicrobials is an increased risk to public health. Molecular-based future studies are needed in order to assess the microbiome residing in , as a research on the hypotheses that intracellular microbes can affect the pathogenicity of infections.
PubMed: 33670718
DOI: 10.3390/pathogens10020225 -
Genotyping determination of Acanthamoeba strains: an original study and a systematic review in Iran.Journal of Water and Health Oct 2019This study aimed to detect the presence of Acanthamoeba spp. in different water resources of Zahedan, southeast of Iran, and also systematically reviewed all...
This study aimed to detect the presence of Acanthamoeba spp. in different water resources of Zahedan, southeast of Iran, and also systematically reviewed all publications regarding Acanthamoeba in Iran (2005-2018). Fifty water samples were collected from different water resources in Zahedan. The positive samples were identified morphologically and subjected to polymerase chain reaction (PCR) using fragments of 18S rRNA. In the systematic review, data collection using particular terms was carried out using the following electronic databases including Science Direct, ISI Web of Science, MEDLINE, EBSCO, Scopus, and Google Scholar. A total of 17 (34%) samples were positive for Acanthamoeba spp., and nucleotide sequencing indicated that 15 samples (88.23%) belonged to the T4 genotype and the rest belonged to the T5 genotype. A total of 39 studies reported genotyping of Acanthamoeba spp. from various geographical areas of Iran and revealed that T4 (35 studies), T5 (19 studies), T3 (11 studies), T11 (8 studies), and T2 (6 studies) genotypes were the most prevalent in Iran. The T4 genotype of Acanthamoeba is a prevalent free-living amoeba and widely distributed not only in Zahedan but also in other provinces of Iran. Phylogenetic analysis reveals that A. castellanii and A. griffini predominantly colocalize with the T4 genotype.
Topics: Acanthamoeba; Environmental Monitoring; Fresh Water; Genotype; Iran; Phylogeny; RNA, Ribosomal, 18S; Water Supply
PubMed: 31638023
DOI: 10.2166/wh.2019.048 -
The Ocular Surface Oct 2019The purpose of this study was to review the published incidence, etiology, clinical features and management of patients who developed infectious interface keratitis...
PURPOSE
The purpose of this study was to review the published incidence, etiology, clinical features and management of patients who developed infectious interface keratitis (IIK) following lamellar keratoplasty.
DESIGN
This study is a systematic literature review.
METHODS
We conducted a systematic review of published Chinese and English report through a PubMed search with the medical subject headings using the following terms: corneal transplantation, keratoplasty, anterior lamellar keratoplasty (ALK), deep anterior lamellar keratoplasty (DALK), deep lamellar endothelial keratoplasty (DLEK), Descemet membrane endothelial keratoplasty (DMEK), Descemet stripping endothelial keratoplasty (DSEK), Descemet stripping automated endothelial keratoplasty (DSAEK), infectious interface keratitis (IIK), fungal keratitis, and bacterial keratitis. Data collected included patient demographics, surgical technique, clinical signs, treatment, outcomes, and donor rim cultures. A review of the relevant literatures was also undertaken.
RESULTS
From 2007 to Feb. 2018, we identified 62 cases of IIK following lamellar corneal surgery. The mean age was 26.95 ± 8.80 years with a male/female ratio of 11:8 in DALK/ALK group and 69.65 ± 8.00 years with a male/female ratio of 17:16 in DSAEK/DSEK/DMEK group (no gender information for 10 cases). Of the 62 cases, 46 cases (75.41%) were fungal, 9 cases (14.75%) were bacterial, 2 cases (3.28%) were Actinomyces species, 1 case (1.64%) was acanthamoeba, and 4 cases (6.56%) were indeterminant. The mean onset of symptoms was postoperative day (POD) 49.47 ± 48.56 in DALK/ALK group, and 53 ± 112.01 in EK group, and 62.44 ± 50.07 for the bacterial keratitis, and 51.5 ± 102.42 for fungal keratitis. The mean postoperative follow-up period was 10.10 ± 9.36 months in DALK/ALK group and 12.37 ± 12.28 months in DSAEK/DSEK/DMEK group. Of the total 62 cases, 1 case (1.61%) with a Klebsiella pneumoniae positive donor rim cultures was associated with the same pathogen in the IIK, and 16 cases (25.81%) of fungal positive donor rim cultures were associated with the same pathogen in the IIK. Clinical signs included conjunctival injection, interface opacity, stromal edema for bacterial keratitis, and dense white infiltrates at the interface with endothelial plaques in some cases of fungal keratitis. Medical treatment included topical and oral antimicrobial agents. Surgical interventions included therapeutic keratoplasty. In 15 cases (24.19%), medical management was successful. Of the remaining 47 cases, 8 (12.90%) were managed with a repeat lamellar keratoplasty (LK) and 39 (62.90%) were unresponsive to conservative medical treatment and underwent a therapeutic keratoplasty (TKP). Post infectious best corrected visual acuity (BCVA) was logMAR 0 in 7 eyes (11.29%), better than or equal to logMAR 0.4 in 20 eyes (32.26%), less than logMAR 0.4 in 22 eyes (35.48%) and logMAR 0.7 or worse in 13 eyes (20.97%). In the rim culture negative group(n = 19), the average BCVA was logMAR 0.59 ± 0.68, with was logMAR 0.44 ± 0.74 in rim culture positive group (n = 15). There were three recurrence cases were reported after DMEK during the postoperative follow-up period.
CONCLUSIONS
Infectious interface keratitis (IIK) is an uncommon complication of lamellar keratoplasty, but it can result in a substantial loss of vision or permanent blindness. Although graft infection can occur at any time following surgery, it most commonly (87%) occurred during the first 3 months postoperatively (54/62 cases). The most commonly reported causative organism of IIK following lamellar keratoplasty was C. albicans. Positive rim culture results can provide more rapid and appropriate treatment directed to the identified organism. Therapeutic keratoplasty (TKP) was the most common surgical procedure for the management of IIK. Visual outcomes post TKP are fair with 32.26% (20/62) of patients obtaining LogMAR 0.4 or better.
Topics: Corneal Transplantation; Eye Infections, Bacterial; Global Health; Graft Survival; Humans; Incidence; Keratitis; Surgical Wound Infection; Visual Acuity
PubMed: 31415815
DOI: 10.1016/j.jtos.2019.08.001 -
The Ocular Surface Oct 2019To examine the efficacy of adjuvant photoactivated chromophore for infectious keratitis-corneal cross-linking (PACK-CXL) for the treatment of infectious keratitis (IK). (Meta-Analysis)
Meta-Analysis
PURPOSE
To examine the efficacy of adjuvant photoactivated chromophore for infectious keratitis-corneal cross-linking (PACK-CXL) for the treatment of infectious keratitis (IK).
METHODS
Electronic databases, including MEDLINE, EMBASE and Cochrane Central, were searched for articles related to PACK-CXL. All clinical studies, including randomized controlled trials (RCTs), non-randomized controlled studies, case series and case reports, were included. A meta-analysis was further performed when there were sufficient similarities in the included RCTs. Primary outcome measure was time to complete corneal healing and secondary outcome measures included size of epithelial defect and infiltrate, corrected-distance-visual-acuity (CDVA), and adverse events.
RESULTS
Forty-six eligible studies (including four RCTs) with 435 patients were included. When compared to standard antimicrobial treatment (SAT) alone, adjuvant PACK-CXL resulted in shorter mean time to complete corneal healing (-7.44 days; 95% CI, -10.71 to -4.16) and quicker resolution of the infiltrate at 7 days (-5.49 mm; 95% CI, -7.44 to -3.54) and at 14-30 days (-5.27 mm; 95% CI, -9.12 to -1.41). There was no significant difference in the size of epithelial defect, CDVA and risk of adverse events. Evidence on the use of PACK-CXL in acanthamoeba and mixed IK was insufficient.
CONCLUSIONS
Our study demonstrates that adjuvant PACK-CXL expedites the healing of IK when compared to SAT alone (low-quality evidence). Further adequately powered, high-quality RCTs are required to fully ascertain the therapeutic effect of PACK-CXL.
Topics: Chromophore-Assisted Light Inactivation; Collagen; Cross-Linking Reagents; Eye Infections, Bacterial; Humans; Keratitis; Photochemotherapy; Photosensitizing Agents; Riboflavin; Visual Acuity
PubMed: 31401338
DOI: 10.1016/j.jtos.2019.08.006