1
|
Ujszegi J, Boros Z, Fodor A, Vajna B, Hettyey A. Metabolites of Xenorhabdus bacteria are potent candidates for mitigating amphibian chytridiomycosis. AMB Express 2023; 13:88. [PMID: 37615904 PMCID: PMC10449739 DOI: 10.1186/s13568-023-01585-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/20/2023] [Indexed: 08/25/2023] Open
Abstract
Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), has caused extreme losses in amphibian biodiversity. Finding bacteria that produce metabolites with antifungal properties may turn out to be invaluable in the fight against this devastating disease. The entomopathogenic bacteria, Xenorhabdus szentirmaii and X. budapestensis produce secondary metabolites that are effective against a wide range of fungal plant pathogens. To assess whether they may also be effective against Bd, we extracted cell-free culture media (CFCM) from liquid cultures of X. szentirmaii and X. budapestensis and tested their ability to inhibit Bd growth in vitro. As a second step, using juvenile common toads (Bufo bufo) experimentally infected with Bd we also tested the in vivo antifungal efficacy of X. szentirmaii CFCM diluted to 2 and 10% (v/v), while also assessing possible malign side effects on amphibians. Results of the in vitro experiment documented highly effective growth inhibition by CFCMs of both Xenorhabdus species. The in vivo experiment showed that treatment with CFCM of X. szentirmaii applied at a dilution of 10% resulted in infection intensities reduced by ca. 73% compared to controls and to juvenile toads treated with CFCM applied at a dilution of 2%. At the same time, we detected no negative side effects of treatment with CFCM on toad survival and development. Our results clearly support the idea that metabolites of X. szentirmaii, and perhaps of several other Xenorhabdus species as well, may prove highly useful for the treatment of Bd infected amphibians.
Collapse
Affiliation(s)
- János Ujszegi
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest, Hungary.
- Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary.
| | - Zsófia Boros
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest, Hungary
- Department of Genetics, Eötvös Loránd University, Budapest, Hungary
- Department of Microbiology, Eötvös Loránd University, Budapest, Hungary
| | - András Fodor
- Department of Genetics, Eötvös Loránd University, Budapest, Hungary
| | - Balázs Vajna
- Department of Microbiology, Eötvös Loránd University, Budapest, Hungary
| | - Attila Hettyey
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest, Hungary
- Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary
| |
Collapse
|
2
|
Yang X, Guo W, Umar A, Algadi H, Ibrahim AA, Zhao C, Ren Z, Wang L, Pei M. Electrochemical aptasensor based on gold nanoparticle decorated Ti 3C 2T x nanocomposites for chloramphenicol detection. Mikrochim Acta 2023; 190:206. [PMID: 37162685 DOI: 10.1007/s00604-023-05772-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 03/29/2023] [Indexed: 05/11/2023]
Abstract
Using gold (Au) nanoparticle decorated Ti3C2Tx (Ti3C2Tx-Au) nanocomposites, a highly sensitive electrochemical aptasensor for the effective detection of chloramphenicol has been developed. As a two-dimensional layered material, the prepared composite not only provides high surface area, good conductivity, and thermal stability but also substantial binding sites for aptamers with high sensitivity and selectivity for the accurate determination of chloramphenicol. Interestingly, the conductivity and active sites were enhanced by freeze-drying Ti3C2Tx and in situ formation of Ti3C2Tx-Au nanocomposite. The fabricated aptasensor exhibited a very low detection limit (S/N ≥ 3) of 13.18 fg mL-1 with a linear range of 1 ~ 700 pg mL-1 and correlation coefficient of 0.9992. The fabricated aptasensor demonstrated an excellent reproducibility, repeatability, long-term stability, and high selectivity toward chloramphenicol. Further, the aptasensor was applied to real milk samples, and the recoveries were ranged from 98.93 to 101.93%.
Collapse
Affiliation(s)
- Xueying Yang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| | - Wenjuan Guo
- Institute of Surface Analysis and Chemical Biology, University of Jinan, Jinan, 250022, China.
| | - Ahmad Umar
- Department of Chemistry, College of Science and Arts, Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, Najran, 11001, Kingdom of Saudi Arabia.
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA.
- Centre for Scientific and Engineering Research, Najran University, Najran, 11001, Saudi Arabia.
| | - Hassan Algadi
- Centre for Scientific and Engineering Research, Najran University, Najran, 11001, Saudi Arabia
- Department of Electrical Engineering, College of Engineering, Najran University, Najran, 11001, Kingdom of Saudi Arabia
| | - Ahmed A Ibrahim
- Department of Chemistry, College of Science and Arts, Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, Najran, 11001, Kingdom of Saudi Arabia
- Centre for Scientific and Engineering Research, Najran University, Najran, 11001, Saudi Arabia
| | - Chengxian Zhao
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| | - Zhe Ren
- Institute of Surface Analysis and Chemical Biology, University of Jinan, Jinan, 250022, China
| | - Luyan Wang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| | - Meishan Pei
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China
| |
Collapse
|
3
|
EFFICACY AND SAFETY OF CHLORAMPHENICOL TREATMENT FOR BATRACHOCHYTRIUM DENDROBATIDIS IN HELLBENDERS ( CRYPTOBRANCHUS ALLEGANIENSIS). J Zoo Wildl Med 2021; 52:373-378. [PMID: 33827201 DOI: 10.1638/2019-0051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2020] [Indexed: 11/21/2022] Open
Abstract
Thirteen wild-caught hellbenders (Cryptobranchus alleganiensis) were treated for Batrachochytrium dendrobatidis with continuous chloramphenicol baths at concentrations of 20 mg/L for 14 days and 200 mg/L for 14 days. Clinical signs and deaths continued after treatment with 20 mg/L chloramphenicol but ceased after treatment with 200 mg/L chloramphenicol. No evidence of toxicity was found on hematologic tests, necropsy, or histopathologic examination. Lower infection burdens were detected after treatment with chloramphenicol, but infection rates were unchanged. Chloramphenicol may be useful as a treatment for B. dendrobatidis in hellbenders but did not clear hellbenders of infection.
Collapse
|
4
|
Llewelyn VK, Berger L, Glass BD. Predicting in vivo absorption of chloramphenicol in frogs using in vitro percutaneous absorption data. BMC Vet Res 2021; 17:57. [PMID: 33509166 PMCID: PMC7842057 DOI: 10.1186/s12917-021-02765-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 01/13/2021] [Indexed: 12/15/2022] Open
Abstract
Background Infectious disease, particularly the fungal disease chytridiomycosis (caused by Batrachochytrium dendrobatidis), is a primary cause of amphibian declines and extinctions worldwide. The transdermal route, although offering a simple option for drug administration in frogs, is complicated by the lack of knowledge regarding percutaneous absorption kinetics. This study builds on our previous studies in frogs, to formulate and predict the percutaneous absorption of a drug for the treatment of infectious disease in frogs. Chloramphenicol, a drug with reported efficacy in the treatment of infectious disease including Batrachochytrium dendrobatidis, was formulated with 20% v/v propylene glycol and applied to the ventral pelvis of Rhinella marina for up to 6 h. Serum samples were taken during and up to 18 h following exposure, quantified for chloramphenicol content, and pharmacokinetic parameters were estimated using non-compartmental analysis. Results Serum levels of chloramphenicol reached the minimum inhibitory concentration (MIC; 12.5 μg.mL− 1) for Batrachochytrium dendrobatidis within 90–120 min of exposure commencing, and remained above the MIC for the remaining exposure time. Cmax (17.09 ± 2.81 μg.mL− 1) was reached at 2 h, while elimination was long (t1/2 = 18.68 h). Conclusions The model, based on in vitro data and adjusted for formulation components and in vivo data, was effective in predicting chloramphenicol flux to ensure the MIC for Batrachochytrium dendrobatidis was reached, with serum levels being well above the MICs for other common bacterial pathogens in frogs. Chloramphenicol’s extended elimination means that a 6-h bath may be adequate to maintain serum levels for up to 24 h. We suggest trialling a reduction of the currently-recommended continuous (23 h/day for 21–35 days) chloramphenicol bathing for chytrid infection with this formulation. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-021-02765-5.
Collapse
Affiliation(s)
- Victoria K Llewelyn
- Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Australia. .,College of Nursing and Health Sciences, Flinders University, Adelaide, Australia.
| | - Lee Berger
- One Health Research Group, Melbourne Veterinary School, University of Melbourne, Werribee, Australia
| | - Beverley D Glass
- Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Australia
| |
Collapse
|
5
|
Ujszegi J, Molnár K, Hettyey A. How to disinfect anuran eggs? Sensitivity of anuran embryos to chemicals widely used for the disinfection of larval and post-metamorphic amphibians. J Appl Toxicol 2020; 41:387-398. [PMID: 32830870 DOI: 10.1002/jat.4050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/20/2020] [Accepted: 07/28/2020] [Indexed: 12/24/2022]
Abstract
Emerging infectious diseases are major drivers of global and local amphibian biodiversity loss. Therefore, developing effective disinfection methods to manage the impact of diseases in wild and captive "ark" populations are an important goal in amphibian conservation. While chemical disinfectants have been used safely and effectively in larval and adult amphibians infected with pathogenic microbes, their applicability to amphibian egg masses has remained untested. To bridge this gap, we exposed embryos of the common toad (Bufo bufo) and agile frog (Rana dalmatina) experimentally to three widely used disinfectants: voriconazole, chloramphenicol and chlorogen-sesquihydrate. For 3 days we exposed portions of egg masses to these disinfectants at 1×, 2×, 5× and 10× the concentration recommended for the disinfection of tadpoles and adults. Subsequently, we recorded embryonic and larval survival, as well as larval body mass and the incidence of abnormalities 12 days after hatching. Application of voriconazole had species- and concentration-dependent negative impacts on survival and body mass, and caused marked malformations in the viscerocranial structure of B. bufo tadpoles. Exposure to chlorogen-sesquihydrate also resulted in significant mortality in B. bufo embryos and negatively affected body mass of R. dalmatina larvae. Chloramphenicol had little negative effects on embryos or larvae in either species. Based on these results, the application of voriconazole and chlorogen-sesquihydrate cannot be recommended for the disinfection of amphibian eggs, whereas treatment with chloramphenicol appears to be a safe method for eliminating potential pathogens from anuran egg masses and their immediate aquatic environment.
Collapse
Affiliation(s)
- János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Budapest, Hungary
| | - Kinga Molnár
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Budapest, Hungary
| |
Collapse
|
6
|
Silva S, Matz L, Elmassry MM, San Francisco MJ. Characteristics of monolayer formation in vitro by the chytrid Batrachochytrium dendrobatidis. Biofilm 2019; 1:100009. [PMID: 33447796 PMCID: PMC7798445 DOI: 10.1016/j.bioflm.2019.100009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/26/2019] [Accepted: 10/24/2019] [Indexed: 12/01/2022] Open
Abstract
Batrachochytrium dendrobatidis is a globally distributed generalist pathogen that has driven many amphibian populations to extinction. The life cycle of B. dendrobatidis has two main cell types, motile zoospores, and sessile reproductive sporangia. When grown in a nutrient-rich liquid medium, B. dendrobatidis forms aggregates of sporangia that transition into monolayers on surfaces and at the air-liquid interface. Pathogenic microorganisms use biofilms as mechanisms of group interactions to survive under harsh conditions in the absence of a suitable host. We used fluorescent and electron microscopy, crystal violet, transcriptomic, and gas chromatographic analyses to understand the characteristics of B. dendrobatidis monolayers. The cell-free monolayer fraction showed the presence of extracellular ribose, mannose, xylose, galactose, and glucose. Transcriptome analysis showed that 27%, 26%, and 4% of the genes were differentially expressed between sporangia/zoospores, monolayer/zoospores, and sporangia/monolayer pairs respectively. In pond water studies, zoospores developed into sporangia and formed floating aggregates at the air-water interface and attached film on the bottom of growth flasks. We propose that B. dendrobatidis can form surface-attached monolayers in nutrient-rich environments and aggregates of sporangia in nutrient-poor aquatic systems. These monolayers and aggregates may facilitate dispersal and survival of the fungus in the absence of a host. We provide evidence for using a combination of plant-based chemicals, allicin, gingerol, and curcumin as potential anti-chytrid drugs to mitigate chytridiomycosis.
Collapse
Affiliation(s)
- Shalika Silva
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Lisa Matz
- Baylor College of Medicine, Houston, TX, USA
| | - Moamen M Elmassry
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | | |
Collapse
|
7
|
Bradley PW, Snyder PW, Blaustein AR. Host age alters amphibian susceptibility to Batrachochytrium dendrobatidis, an emerging infectious fungal pathogen. PLoS One 2019; 14:e0222181. [PMID: 31491016 PMCID: PMC6730893 DOI: 10.1371/journal.pone.0222181] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 08/23/2019] [Indexed: 11/18/2022] Open
Abstract
Parasites and pathogens are often aggregated in a minority of susceptible hosts within a population, with a majority of individuals harboring low infection intensities. However, determining the relative importance of host traits to explain this heterogeneity is a challenge. One ecologically important pathogen is Batrachochytrium dendrobatidis (Bd), which causes the disease chytridiomycosis and has been associated with many amphibian population declines worldwide. For many hosts, post-metamorphic stages are generally more susceptible than the larval stage. Yet, examination of the effects of Bd infection at different ages within a life stage, has received little attention. This study investigated the hypothesis that recently-post-metamorphic frogs were more sensitive to chytridiomycosis than older frogs, and that sensitivity to Bd infection decreased as frogs aged. We examined this relationship with Pacific treefrogs (Pseudacris regilla) and red legged frogs (Rana aurora). Age had a strong effect on susceptibility to infection, infection intensity, and survival-but not in the directions we had predicted. In both host species, an increase in age was associated with frogs becoming more susceptible to Bd infection, harboring larger infection intensities, and greater risk of mortality. This suggests that the timing of Bd exposure may influence amphibian population dynamics.
Collapse
Affiliation(s)
- Paul W. Bradley
- Environmental Sciences Graduate Program, Oregon State University, Corvallis, Oregon, United States of America
- * E-mail:
| | - Paul W. Snyder
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Andrew R. Blaustein
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| |
Collapse
|
8
|
Robak MJ, Reinert LK, Rollins-Smith LA, Richards-Zawacki CL. Out in the cold and sick: Low temperatures and fungal infections impair a frog's skin defenses. J Exp Biol 2019; 222:jeb.209445. [DOI: 10.1242/jeb.209445] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 09/02/2019] [Indexed: 12/29/2022]
Abstract
Amphibians worldwide continue to battle an emerging infectious disease, chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd). Southern leopard frogs, Rana sphenocephala, are known to become infected with this pathogen, yet they are considered ‘of least concern’ for declines due to chytridiomycosis. Previous studies have shown that R. sphenocephala secretes four antimicrobial peptides (AMPs) onto their skin which may play an important role in limiting susceptibility to chytridiomycosis. Here we examined the (1) effects of temperature and AMP depletion on infections with Bd and (2) effects of temperature and Bd infection on the capacity to secrete AMPs in juvenile leopard frogs. Pathogen burden and mortality were greater in frogs exposed to Bd at low temperature but did not increase following monthly AMP depletion. Both low temperature and Bd exposure reduced the capacity of juvenile frogs to restore peptides after monthly depletions. Frogs held at 14°C were poorly able to restore peptides in comparison with those at 26 °C. Frogs held at 26 °C were better able to restore their peptides, but when exposed to Bd, this capacity was significantly reduced. These results strongly support the hypothesis that both colder temperatures and Bd infections impair the capacity of juvenile frogs to produce and secrete AMPs, an important component of their innate defense against chytrid fungi and other pathogens. Thus, in the face of unpredictable climate changes and enzootic pathogens, assessments of disease risk should consider the potential for effects of environmental variation and pathogen exposure on the quality of host defenses.
Collapse
Affiliation(s)
- Matthew J. Robak
- Department of Ecology & Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA
| | - Laura K. Reinert
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Louise A. Rollins-Smith
- Department of Pathology, Microbiology and Immunology Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Corinne L. Richards-Zawacki
- Department of Ecology & Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| |
Collapse
|
9
|
Fernández-Loras A, Martín-Beyer B, Garner TWJ, Bosch J. Itraconazole and thiophanate-methyl fail to clear tadpoles naturally infected with the hypervirulent lineage of Batrachochytrium dendrobatidis. DISEASES OF AQUATIC ORGANISMS 2018; 131:73-78. [PMID: 30324916 DOI: 10.3354/dao03282] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The emerging infectious disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, is a major driver pushing many amphibian species to the brink of extinction. Substantial efforts to develop effective protocols that use antifungal drugs have had notable success. Here, we used the antifungal agents itraconazole and thiophanate-methyl, singly and in combination, in an attempt to treat common midwife toad Alytes obstetricans larvae naturally infected with the globalized hypervirulent lineage of B. dendrobatidis. Despite the successful use of itraconazole in a closely related species (A. muletensis), our results show that these antifungal treatments are not always effective and that full clearance of animals cannot be assumed following treatment.
Collapse
|
10
|
Roberts AA, Berger L, Robertson SG, Webb RJ, Kosch TA, McFadden M, Skerratt LF, Glass BD, Motti CA, Brannelly LA. The efficacy and pharmacokinetics of terbinafine against the frog-killing fungus (Batrachochytrium dendrobatidis). Med Mycol 2018; 57:204-214. [DOI: 10.1093/mmy/myy010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alexandra A Roberts
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia
| | - Sherryl G Robertson
- Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Australia
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
| | - Tiffany A Kosch
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia
| | - Michael McFadden
- Taronga Conservation Society Australia, Herpetofauna Division, Mosman, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia
| | - Beverley D Glass
- Pharmacy, College of Medicine and Dentistry, James Cook University, Townsville, Australia
| | - Cherie A Motti
- Australian Institute of Marine Science, Townsville, Australia
| | - Laura A Brannelly
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Australia
- Department of Biological Sciences, University of Pittsburgh, Pittsburg, Pennsylvania, USA
| |
Collapse
|
11
|
THE PHARMACOKINETICS OF TOPICAL ITRACONAZOLE IN PANAMANIAN GOLDEN FROGS (ATELOPUS ZETEKI). J Zoo Wildl Med 2017; 48:344-351. [DOI: 10.1638/2015-0218r2.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
12
|
Loyau A, Cornuau JH, Clare FC, Schmeller DS. Side effects of itraconazole on post-metamorphic Alytes obstetricans after a cold stress. AMPHIBIA-REPTILIA 2016. [DOI: 10.1163/15685381-00003064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Itraconazole is the most widely used treatment against Batrachochytrium dendrobatidis (Bd), the fungal pathogen causing chytridiomycosis, a proximate cause of amphibian declines. Several side effects of itraconazole treatment, ranging in severity from depigmentation to death have been reported in different amphibian species and life stages, and these side effects were observed at commonly used dosages of itraconazole. However, no studies have investigated side-effects of itraconazole in conjunction with environmental stress. Post-metamorphic midwife toads (Alytes obstetricans) that were treated with itraconazole and subsequently exposed to a cold stress (exposure to 4°C cold water) had higher mortality rates compared to untreated individuals. Moreover, adults of booroolong frogs (Litoria booroolongensis) treated with itraconazole had a higher probability to become infected when subsequently exposed to Bd. Our results suggest that a post-metamorphosis itraconazole treatment of infected midwife toads combined with a subsequent release into the wild may be an ineffective disease mitigation strategy, as the cold stress during hibernation and/or exposure to Bd in the wild may reduce the hibernation emergence rate of treated individuals in this species.
Collapse
Affiliation(s)
- Adeline Loyau
- Department of Conservation Biology, Helmholtz Centre for Environmental Research – UFZ, Permoserstrasse 15, 04138 Leipzig, Germany
- Department of System Ecotoxicology, Helmholtz Centre for Environmental Research – UFZ, Permoserstrasse 15, 04138 Leipzig, Germany
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | | | - Frances C. Clare
- Department of Conservation Biology, Helmholtz Centre for Environmental Research – UFZ, Permoserstrasse 15, 04138 Leipzig, Germany
- ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Dirk S. Schmeller
- Institute of Zoology, Zoological Society of London, Regent’s Park, London, NW1 4RY, UK
- Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
| |
Collapse
|
13
|
Brannelly LA, Skerratt LF, Berger L. Treatment trial of clinically ill corroboree frogs with chytridiomycosis with two triazole antifungals and electrolyte therapy. Vet Res Commun 2015; 39:179-87. [PMID: 26246159 DOI: 10.1007/s11259-015-9642-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/29/2015] [Indexed: 10/23/2022]
Abstract
Chytridiomycosis caused by the pathogen Batrachochytrium dendrobatidis is an important cause of amphibian declines globally, and is the worst pathogen on record for causing biodiversity loss. The critically endangered southern corroboree frog, Pseudophryne corroboree, is functionally extinct in the wild and is surviving in captive assurance colonies. These captive colonies must remain disease free, and there is no known treatment for corroboree frogs with terminal chytridiomycosis. In this study we tested two triazole antifungals (itraconazole and voriconazole) coupled with aggressive electrolyte therapy on moribund corroboree frogs with severe chytridiomycosis. Six moribund frogs were given 20 mL baths of 0.5 μg/mL itraconazole for 5 min/day for 5 days coupled with electrolyte injections every 8 h for 3 days followed by every 12 h for 3 days. Six other moribund frogs were given 1 mL drops of 1.25 μg/mL voriconazole daily for 7 days coupled with the aggressive electrolyte therapy. While only one animal survived this treatment regime, time until death was extended for all animals by at least 3 days and infection load decreased by an average of 89.3%. Our results suggest there is potential for recovery of terminally ill P. corroboree, and we suggest further trials include antibiotics as well as exploring variations on the above treatment regime with other antifungals.
Collapse
Affiliation(s)
- Laura A Brannelly
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia,
| | | | | |
Collapse
|
14
|
Holden WM, Reinert LK, Hanlon SM, Parris MJ, Rollins-Smith LA. Development of antimicrobial peptide defenses of southern leopard frogs, Rana sphenocephala, against the pathogenic chytrid fungus, Batrachochytrium dendrobatidis. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2015; 48:65-75. [PMID: 25218643 DOI: 10.1016/j.dci.2014.09.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 06/03/2023]
Abstract
Amphibian species face the growing threat of extinction due to the emerging fungal pathogen Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis. Antimicrobial peptides (AMPs) produced in granular glands of the skin are an important defense against this pathogen. Little is known about the ontogeny of AMP production or the impact of AMPs on potentially beneficial symbiotic skin bacteria. We show here that Rana (Lithobates) sphenocephala produces a mixture of four AMPs with activity against B. dendrobatidis, and we report the minimum inhibitory concentration (MIC) of synthesized replicates of these four AMPs tested against B. dendrobatidis. Using mass spectrometry and protein quantification assays, we observed that R. sphenocephala does not secrete a mature suite of AMPs until approximately 12 weeks post-metamorphosis, and geographically disparate populations produce a different suite of peptides. Use of norepinephrine to induce maximal secretion significantly reduced levels of culturable skin bacteria.
Collapse
Affiliation(s)
- Whitney M Holden
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Laura K Reinert
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Shane M Hanlon
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Matthew J Parris
- Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Louise A Rollins-Smith
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| |
Collapse
|
15
|
Brannelly LA, Berger L, Marrantelli G, Skerratt LF. Low humidity is a failed treatment option for chytridiomycosis in the critically endangered southern corroboree frog. WILDLIFE RESEARCH 2015. [DOI: 10.1071/wr14097] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
One of the major drivers of the current worldwide amphibian decline and extinction crisis is the spread of the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd). Captive assurance colonies may be the only lifeline for some species. Current antifungal chemotherapies can be effective for clearing infection but may have detrimental side effects. The only non-chemotherapeutic treatment that has been clinically tested is heat, which is impractical for cold-adapted species. The fungus does not survive desiccation, and therefore a plausible alternative non-chemotherapeutic treatment would be a low-humidity regimen.
Aims
We tested the efficacy of a low-humidity treatment regimen for treating Bd-infected animals of the critically endangered species Pseudophryne corroboree. This species has high tolerance of dry environments, and is thus an ideal candidate for this treatment trial.
Methods
Forty frogs were exposed to 1 × 106 zoospores. At three weeks after exposure access to water was reduced to once daily for 10 days for 20 animals. Ten of these animals were also rinsed daily with the aim of removing zoospores.
Key results
The drying regimen neither increased survival nor decreased infection load, and treatment may have hastened mortality. All infected frogs died between 21 and 80 days after exposure, except one untreated frog.
Conclusions
Our results suggest that a drying regimen is not a viable treatment for chytridiomycosis. Infection may decrease the host’s ability to cope with water stress.
Implications
The failed drying treatment in P. corroboree suggests that drying is not an appropriate treatment for chytridiomycosis and treatment efforts should be focussed on chemotherapies for cold-adapted species. P. corroboree is a critically endangered species for which chytridiomycosis is the primary cause of decline, yet few experiments have been carried out on this species with regards to chytridiomycosis. All experimental information about this species and disease will benefit the management and protection of the species.
Collapse
|
16
|
In vitro anti-yeast activity of chloramphenicol: A preliminary report. J Mycol Med 2014; 25:17-22. [PMID: 25497707 DOI: 10.1016/j.mycmed.2014.10.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 10/03/2014] [Accepted: 10/20/2014] [Indexed: 11/20/2022]
Abstract
Chloramphenicol is a bacteriostatic antimicrobial agent but its antifungal activity is not known. The present study aimed to investigate the activity of chloramphenicol against 30 representative yeasts. The antimicrobial assay of chloramphenicol (50mg/mL; 100mg/mL and 200mg/mL) was determined by the disc diffusion method using Mueller-Hinton agar against 30 representative yeast strains. Zone of inhibition was read after 48-72h incubation at 37°C and results were compared with some standard antifungal agents. Most of the tested yeasts (73.3%) showed inhibition zones (5 up to 35mm) to chloramphenicol impregnated discs (200mg/mL). Three out of the four tested Candida albicans as well as Candida famata, Candida glabrata, Candida haemolonei and Cryptococcus neoformans showed no inhibition zones to chloramphenicol (200mg/mL). Caspofungin acetate (50mg/mL) inhibited 83.3% of the strains; ketoconazole (200mg/mL) 70% and metronidazole 10%. Chloramphenicol discs: 50 and 100mg/mL showed less activity (6.7% and 36.7%, respectively) compared to the 200mg discs; whereas chloramphenicol (BBL; 3μg/mL) inhibited 13.3% of the strains. The anti-yeast activities of chloramphenicol were comparable to other known antifungal compounds. Moreover, it is cheap, has fewer side effects and its inclusions in selective fungal media such as Mycosel have to be questioned.
Collapse
|