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...

Full description

Bibliographic Details
Main Authors: Janelle S Renschler, Gary D Norsworthy, Rubie A Rakian, Audrey I Rakian, Lawrence J Wheat, Andrew S Hanzlicek
Format: Article
Language:English
Published: SAGE Publishing 2017-11-01
Series:Journal of Feline Medicine and Surgery Open Reports
Online Access:https://doi.org/10.1177/2055116917743364
id doaj-8cecb76cde964b3b8036e9bbab9d0900
record_format Article
spelling 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
work_keys_str_mv AT janellesrenschler reducedsusceptibilitytofluconazoleinacatwithhistoplasmosis
AT garydnorsworthy reducedsusceptibilitytofluconazoleinacatwithhistoplasmosis
AT rubiearakian reducedsusceptibilitytofluconazoleinacatwithhistoplasmosis
AT audreyirakian reducedsusceptibilitytofluconazoleinacatwithhistoplasmosis
AT lawrencejwheat reducedsusceptibilitytofluconazoleinacatwithhistoplasmosis
AT andrewshanzlicek reducedsusceptibilitytofluconazoleinacatwithhistoplasmosis
_version_ 1724558999623303168