Reduced susceptibility to fluconazole in a cat with histoplasmosis
Case summary An 11-year-old neutered male domestic longhair cat was diagnosed with histoplasmosis from fine-needle aspirates of an abdominal lymph node. Lymph node size initially decreased with fluconazole therapy (11.8 mg/kg PO q12h); however, after 13 months of continuous fluconazole therapy, lymp...
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doaj-8cecb76cde964b3b8036e9bbab9d09002020-11-25T03:34:23ZengSAGE PublishingJournal of Feline Medicine and Surgery Open Reports2055-11692017-11-01310.1177/2055116917743364Reduced susceptibility to fluconazole in a cat with histoplasmosisJanelle S Renschler0Gary D Norsworthy1Rubie A Rakian2Audrey I Rakian3Lawrence J Wheat4Andrew S Hanzlicek5MiraVista Diagnostics, Indianapolis, IN, USAAlamo Feline Health Center, San Antonio, TX, USADepartment of Cellular and Integrative Physiology, University of Texas Health Science Center, San Antonio, TX, USADepartment of Cellular and Integrative Physiology, University of Texas Health Science Center, San Antonio, TX, USAMiraVista Diagnostics, Indianapolis, IN, USADepartment of Veterinary Clinical Sciences, Oklahoma State University, Stillwater, OK, USACase summary An 11-year-old neutered male domestic longhair cat was diagnosed with histoplasmosis from fine-needle aspirates of an abdominal lymph node. Lymph node size initially decreased with fluconazole therapy (11.8 mg/kg PO q12h); however, after 13 months of continuous fluconazole therapy, lymphadenomegaly worsened and samples were collected for culture and antifungal susceptibility. The Histoplasma capsulatum isolate had a very high fluconazole minimum inhibitory concentration (MIC) of 64 µg/ml and an itraconazole MIC of 0.06 µg/ml. The owner declined a change to itraconazole and, ultimately, the cat developed neurologic signs and was euthanized. Owing to the initial response to fluconazole followed by treatment failure and high MIC value, acquired fluconazole resistance was suspected. Clinical breakpoints for fluconazole for the dimorphic fungi are not available to define true antifungal resistance. Relevance and novel information This is the first published report of reduced susceptibility to fluconazole in a cat being treated for histoplasmosis. Fluconazole failure and increases in MIC between pretreatment and long-term treatment isolates are known to occur in humans with histoplasmosis. Practitioners should be aware of this possibility when treating cats with fluconazole (particularly in cases with long-term [>1 year] fluconazole therapy or in cases with disease recrudescence).https://doi.org/10.1177/2055116917743364 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Janelle S Renschler Gary D Norsworthy Rubie A Rakian Audrey I Rakian Lawrence J Wheat Andrew S Hanzlicek |
spellingShingle |
Janelle S Renschler Gary D Norsworthy Rubie A Rakian Audrey I Rakian Lawrence J Wheat Andrew S Hanzlicek Reduced susceptibility to fluconazole in a cat with histoplasmosis Journal of Feline Medicine and Surgery Open Reports |
author_facet |
Janelle S Renschler Gary D Norsworthy Rubie A Rakian Audrey I Rakian Lawrence J Wheat Andrew S Hanzlicek |
author_sort |
Janelle S Renschler |
title |
Reduced susceptibility to fluconazole in a cat with histoplasmosis |
title_short |
Reduced susceptibility to fluconazole in a cat with histoplasmosis |
title_full |
Reduced susceptibility to fluconazole in a cat with histoplasmosis |
title_fullStr |
Reduced susceptibility to fluconazole in a cat with histoplasmosis |
title_full_unstemmed |
Reduced susceptibility to fluconazole in a cat with histoplasmosis |
title_sort |
reduced susceptibility to fluconazole in a cat with histoplasmosis |
publisher |
SAGE Publishing |
series |
Journal of Feline Medicine and Surgery Open Reports |
issn |
2055-1169 |
publishDate |
2017-11-01 |
description |
Case summary An 11-year-old neutered male domestic longhair cat was diagnosed with histoplasmosis from fine-needle aspirates of an abdominal lymph node. Lymph node size initially decreased with fluconazole therapy (11.8 mg/kg PO q12h); however, after 13 months of continuous fluconazole therapy, lymphadenomegaly worsened and samples were collected for culture and antifungal susceptibility. The Histoplasma capsulatum isolate had a very high fluconazole minimum inhibitory concentration (MIC) of 64 µg/ml and an itraconazole MIC of 0.06 µg/ml. The owner declined a change to itraconazole and, ultimately, the cat developed neurologic signs and was euthanized. Owing to the initial response to fluconazole followed by treatment failure and high MIC value, acquired fluconazole resistance was suspected. Clinical breakpoints for fluconazole for the dimorphic fungi are not available to define true antifungal resistance. Relevance and novel information This is the first published report of reduced susceptibility to fluconazole in a cat being treated for histoplasmosis. Fluconazole failure and increases in MIC between pretreatment and long-term treatment isolates are known to occur in humans with histoplasmosis. Practitioners should be aware of this possibility when treating cats with fluconazole (particularly in cases with long-term [>1 year] fluconazole therapy or in cases with disease recrudescence). |
url |
https://doi.org/10.1177/2055116917743364 |
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