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Roberts D, Salmon J, Cubeta MA, Gilger BC. Phase-Dependent Differential In Vitro and Ex Vivo Susceptibility of Aspergillus flavus and Fusarium keratoplasticum to Azole Antifungals. J Fungi (Basel) 2023; 9:966. [PMID: 37888221 PMCID: PMC10608098 DOI: 10.3390/jof9100966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023] Open
Abstract
Fungal keratitis (FK) is an invasive infection of the cornea primarily associated with Aspergillus and Fusarium species. FK is treated empirically with a limited selection of topical antifungals with varying levels of success. Though clinical infections are typically characterized by a dense network of mature mycelium, traditional models used to test antifungal susceptibility of FK isolates exclusively evaluate susceptibility in fungal cultures derived from asexual spores known as conidia. The purpose of this study was to characterize differences in fungal response when topical antifungal treatment is initiated at progressive phases of fungal development. We compared the efficacy of voriconazole and luliconazole against in vitro cultures of A. flavus and F. keratoplasticum at 0, 24, and 48 h of fungal development. A porcine cadaver corneal model was used to compare antifungal efficacy of voriconazole and luliconazole in ex vivo tissue cultures of A. flavus and F. keratoplasticum at 0, 24, and 48 h of fungal development. Our results demonstrate phase-dependent susceptibility of both A. flavus and F. keratoplasticum to both azoles in vitro as well as ex vivo. We conclude that traditional antifungal susceptibility testing with conidial suspensions does not correlate with fungal susceptibility in cultures of a more advanced developmental phase. A revised method of antifungal susceptibility testing that evaluates hyphal susceptibility may better predict fungal response in the clinical setting where treatment is often delayed until days after the initial insult.
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Affiliation(s)
- Darby Roberts
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA; (D.R.)
| | - Jacklyn Salmon
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA; (D.R.)
| | - Marc A. Cubeta
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC 27606, USA;
| | - Brian C. Gilger
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA; (D.R.)
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Martinez PS, Whitley RD, Plummer CE, Richardson RL, Hamor RE, Wellehan JFX. In vitro antifungal susceptibility of Fusarium species and Aspergillus fumigatus cultured from eleven horses with fungal keratitis. Vet Ophthalmol 2022; 25:376-384. [PMID: 35684950 DOI: 10.1111/vop.12995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 05/15/2022] [Accepted: 05/16/2022] [Indexed: 11/26/2022]
Abstract
PURPOSE To examine the relationship between Minimum Inhibitory Concentration (MICs) and response to therapy of 6 Fusarium spp. and 5 Aspergillus fumigatus isolated from equine ulcerative keratitis cases. PROCEDURE Fungi were identified by morphology and Internal Transcribed Spacer (ITS) polymerase chain reaction (PCR) with sequencing and evaluated at the University of Texas Fungal Testing Laboratory for susceptibility to three azole antifungals (miconazole, voriconazole, posaconazole), natamycin, and two echinocandins (anidulafungin, caspofungin). A Mann-Whitney rank sum test was used for the comparison of time to heal between infections of different fungal genera and in vitro susceptibility to the drug administered. RESULTS Fusarium spp. were resistant to azole antifungals in 6/6 cases (100%). Fusarium spp. were susceptible to echinocandins and natamycin in all cases. A. fumigatus was resistant to anidulafungin in 1/5 cases (20%) and posaconazole in 1/5 cases (20%) The remainder of A. fumigatus isolates were susceptible to all antifungal agents tested. Fusarium isolates were treated with antifungals to which they were not susceptible; however, all cases of A. fumigatus were treated with antifungals to which they were susceptible. All Fusarium cases and A. fumigatus cases experienced clinical resolution, regardless of surgical intervention. There was no statistical correlation between fungal genus and time to heal (p < .082). CONCLUSIONS The in vitro susceptibility indicated that all cases of Fusarium spp. were resistant to azole antifungal drugs which were used as treatment. Clinical outcomes, however, showed that all cases healed despite resistance to antifungals.
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Affiliation(s)
- Paoul S Martinez
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA
| | - R David Whitley
- Department of Small Animal Clinical Sciences, Professor Emeritus, University of Florida, Gainesville, Florida, USA
| | - Caryn E Plummer
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA.,Department of Large Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA
| | - Rebecca L Richardson
- Clinical Microbiology, Parasitology and Serology, University of Florida, Gainesville, Florida, USA
| | - Ralph E Hamor
- Department of Small Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA
| | - James F X Wellehan
- Department of Comparative, Diagnostic & Population Medicine, University of Florida, Gainesville, Florida, USA
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Stewart RM, Lack AC, Telle MR, Ellis JK, Betbeze CM. Dorsally placed commercially available subpalpebral lavage systems have low complication rates in horses. J Am Vet Med Assoc 2022; 260:1057-1062. [DOI: 10.2460/javma.22.01.0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
OBJECTIVE
To retrospectively evaluate the complication rate following dorsal placement of a commercially available 1-hole subpalpebral lavage system (SPL) at a veterinary teaching hospital.
ANIMALS
102 client-owned horses with ophthalmic disease.
PROCEDURES
Medical records of horses (2010 to 2020) with ophthalmic disease were reviewed to determine whether a commercially available SPL system was dorsally placed. Data collected from the medical record included signalment, presenting complaint(s), diagnosis, ophthalmic procedures performed, SPL laterality, hospital service that placed the SPL, anesthetic technique for placement (general anesthesia or sedation with local nerve blocks), duration of SPL management while hospitalized or at home, type of enclosure for the horse, use of eye protection, duration of time the SPL was in place, location of SPL management (home vs hospital), types and numbers of medications administered, recorded complications, and outcome of the globe. Complications experienced during treatment were categorized as either ocular or nonocular. The χ2 test for independence test and Fisher exact test were performed to examine the relationship between the department that placed the SPL, method of anesthesia, antimicrobial administration, type of facial protection used, and complication type and rate.
RESULTS
Overall complication rate for SPL systems was 29.1% (37/127), with 21.2% (27/127) being ocular complications and 7.9% (10/127) being nonocular complications. SPL complication rate was not affected by any variable that was examined.
CLINICAL RELEVANCE
Commercially available SPL systems placed dorsally have a low ocular complication rate. These SPL systems may be placed by veterinarians with varied training backgrounds and managed at home without significantly increasing complication rate.
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Affiliation(s)
- Ruth M. Stewart
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Amy C. Lack
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
| | - Mary R. Telle
- Department of Mathematics, Florida Gulf Coast University, Fort Myers, FL
| | - Jerald K. Ellis
- Department of Mathematics, Florida Gulf Coast University, Fort Myers, FL
| | - Caroline M. Betbeze
- Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS
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Mora-Pereira M, Abarca EM, Duran S, Ravis W, McMullen RJ, Fischer BM, Lee YHP, Wooldridge AA. Sustained-release voriconazole-thermogel for subconjunctival injection in horses: ocular toxicity and in-vivo studies. BMC Vet Res 2020; 16:115. [PMID: 32295599 PMCID: PMC7160932 DOI: 10.1186/s12917-020-02331-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 04/05/2020] [Indexed: 12/13/2022] Open
Abstract
Background Keratomycosis is a relatively common, sight threatening condition in horses, where treatment is often prolonged and costly. Subconjunctival (SCo) injections offer less resistance to drug diffusion than the topical route, resulting in better penetration to the ocular anterior segment. Voriconazole, a second generation triazole antifungal, is effective against common fungal organisms causing keratomycosis. If combined with a thermogel biomaterial, voriconazole can be easily injected in the SCo space to provide sustained drug release. The purpose of this study was to evaluate the drug concentrations in the anterior segment and clinical effects after SCo injections of voriconazole-containing thermogel: poly (DL-lactide-co-glycolide-b-ethylene glycol-b-DL-lactide-co-glycolide) (PLGA-PEG-PLGA) in healthy equine eyes. Results Voriconazole aqueous humor (AH) and tear concentrations were compared between 6 horses, receiving 1% voriconazole applied topically (0.2 mL, q4h) (Vori-Top) or 1.7% voriconazole-thermogel (0.3 mL) injected SCo (Vori-Gel). For the Vori-Gel group, voriconazole concentrations were measured in AH and tears at day 2 and then weekly for 23 days, and at day 2 only for the Vori-Top group. Ocular inflammation was assessed weekly (Vori-Gel) using the modified Hackett-McDonald scoring system. Ocular tissue concentrations of voriconazole following SCo 1.7% voriconazole-thermogel (0.3 mL) injections were evaluated post euthanasia in 6 additional horses at 3 different time points. Three horses received bilateral injections at 2 h (n = 3, right eye (OD)) and 48 h (n = 3, left eye (OS)) prior to euthanasia, and 3 horses were injected unilaterally (OS), 7 days prior to euthanasia. Voriconazole-thermogel was easily injected and well tolerated in all cases, with no major adverse effects. On day 2, drug concentrations in tears were higher in the Vori-Top, but not statistically different from Vori-Gel groups. For the Vori-Gel group, voriconazole was non-quantifiable in the AH at any time point. Total voriconazole concentrations in the cornea were above 0.5 μg/g (the target minimum inhibitory concentration (MIC) for Aspergillus sp.) for up to 48 h; however, concentrations were below this MIC at 7 days post treatment. Conclusions Voriconazole-thermogel was easily and safely administered to horses, and provided 48 h of sustained release of voriconazole into the cornea. This drug delivery system warrants further clinical evaluation.
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Affiliation(s)
- Mariano Mora-Pereira
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | - Eva M Abarca
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA.
| | - Sue Duran
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | - William Ravis
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA
| | - Richard J McMullen
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | - Britta M Fischer
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | | | - Anne A Wooldridge
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
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Mustikka MP, Grönthal TSC, Pietilä EM. Equine infectious keratitis in Finland: Associated microbial isolates and susceptibility profiles. Vet Ophthalmol 2019; 23:148-159. [PMID: 31364808 PMCID: PMC7004187 DOI: 10.1111/vop.12701] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/05/2019] [Accepted: 06/27/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To retrospectively describe laboratory findings, treatment, and outcome associated with equine infectious keratitis in Finland. ANIMALS AND PROCEDURES Medical records of horses diagnosed with infectious keratitis in University of Helsinki Equine Hospital from January 2007 to June 2018 were reviewed. RESULTS Forty-seven cases were included. Keratomycosis was diagnosed in 27 eyes and bacterial keratitis in 20 eyes. Aspergillus flavus was the most frequent fungal isolate (9/17, 53%), followed by Cylindrocarpon sp. (3/17, 18%) and Aspergillus fumigatus (2/17, 12%). Susceptibility was tested for 10/11 Aspergillus sp. isolates; all were susceptible to voriconazole while only two were susceptible to amphotericin B. Cylindrocarpon sp. isolates were resistant to both agents. Streptococcus equi subsp. zooepidemicus was the most frequent bacterial isolate (9/19, 47%), followed by other streptococci (4/19, 21%). All 13 Streptococcus sp. isolates were susceptible to penicillin, and all tested isolates (n = 11) were also susceptible to chloramphenicol. Mean duration of medical treatment was longer in fungal keratitis (38 days) than in bacterial keratitis (25 days) (P < .001). Twenty-six of the eyes underwent globe-sparing surgery in addition to medical therapy. Recovery was achieved in 66% (31/47) of all cases and in 59% (16/27) and 75% (15/20) (P = .264) of cases with keratomycosis and bacterial keratitis, respectively. CONCLUSIONS Although Aspergillus sp. and S zooepidemicus were the most frequently encountered isolates, cytology, culture, and susceptibility testing are essential to differentiate bacterial and fungal keratitis and guide the clinician to choose the most efficient treatment.
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Affiliation(s)
- Minna P Mustikka
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - Thomas S C Grönthal
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - Elina M Pietilä
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
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Cullen M, Jacob ME, Cornish V, VanderSchel IQ, Cotter HVT, Cubeta MA, Carbone I, Gilger BC. Multi-locus DNA sequence analysis, antifungal agent susceptibility, and fungal keratitis outcome in horses from Southeastern United States. PLoS One 2019; 14:e0214214. [PMID: 30921394 PMCID: PMC6438541 DOI: 10.1371/journal.pone.0214214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/09/2019] [Indexed: 11/21/2022] Open
Abstract
Morphological characterization and multi-locus DNA sequence analysis of fungal isolates obtained from 32 clinical cases of equine fungal keratitis (FK) was performed to identify species and determine associations with antifungal susceptibility, response to therapy and clinical outcome. Two species of Aspergillus (A. flavus and A. fumigatus) and three species of Fusarium (F. falciforme, F. keratoplasticum, and F. proliferatum) were the most common fungi isolated and identified from FK horses. Most (91%) equine FK Fusarium nested within the Fusarium solani species complex (FSSC) with nine genetically diverse strains/lineages, while 83% of equine FK Aspergillus nested within the A. flavus clade with three genetically diverse lineages. Fungal species and evolutionary lineage were not associated with clinical outcome. However, species of equine FK Fusarium were more likely (p = 0.045) to be associated with stromal keratitis. Species of Aspergillus were more susceptible to voriconazole and terbinafine than species of Fusarium, while species of Fusarium were more susceptible to thiabendazole than species of Aspergillus. At the species level, A. fumigatus and A. flavus were more susceptible to voriconazole and terbinafine than F. falciforme. Natamycin susceptibility was higher for F. falciforme and A. fumigatus compared to A. flavus. Furthermore, F. falciforme was more susceptible to thiabendazole than A. flavus and A. fumigatus. These observed associations of antifungal sensitivity to natamycin, terbinafine, and thiabendazole demonstrate the importance of fungal identification to the species rather than genus level. The results of this study suggest that treatment of equine FK with antifungal agents requires accurate fungal species identification.
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Affiliation(s)
- Megan Cullen
- Department of Clinical Sciences, NC State University, Raleigh, NC, United States of America
| | - Megan E. Jacob
- Department of Population Health and Pathobiology, NC State University, Raleigh, NC, United States of America
| | - Vicki Cornish
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Ian Q. VanderSchel
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Henry Van T. Cotter
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Marc A. Cubeta
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Ignazio Carbone
- Center for Integrated Fungal Research, College of Agriculture and Life Sciences, NC State University, Raleigh, NC, United States of America
| | - Brian C. Gilger
- Department of Clinical Sciences, NC State University, Raleigh, NC, United States of America
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Therapy of Non-Dermatophytic Mycoses in Animals. J Fungi (Basel) 2018; 4:jof4040120. [PMID: 30380772 PMCID: PMC6308939 DOI: 10.3390/jof4040120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 10/21/2018] [Accepted: 10/29/2018] [Indexed: 12/13/2022] Open
Abstract
This review focuses on aspects of antimycotic therapy specific to veterinary medicine. In the first part, drug availability, limited mostly by economic consideration but also by clinical applicability and specific adverse effects, is described for polyenes, 5 fluorocytosine, azoles, echinocandins and terbinafine. In the second part, current knowledge and experience in the treatment of selected fungal infections are overviewed. These mycoses include disseminated mold infections in small animals (dogs and cats) and avian species, upper respiratory tract infections of small animals (sino-nasal and sino-orbital aspergillosis) and horses (guttural pouch mycosis), eumycetoma, infections caused by dimorphic fungi, (blastomycosis, histoplasmosis, coccidioidomycosis, paracoccidioidomycosis and sporothrichosis) and by yeasts and yeast-like microorganism (Cryptococcus spp. and Malassezia pachydermatis).
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