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Positive Aspergillus PCR as a marker of azole resistance or sub‐therapeutic antifungal therapy in patients with chronic pulmonary aspergillosis
Author(s) -
Moazam Samihah,
Eades Christopher Philip,
Muldoon Eavan Gabrielle,
Moore Caroline B.,
Richardson Malcolm D.,
RautemaaRichardson Riina
Publication year - 2020
Publication title -
mycoses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 69
eISSN - 1439-0507
pISSN - 0933-7407
DOI - 10.1111/myc.13052
Subject(s) - itraconazole , posaconazole , azole , aspergillus fumigatus , voriconazole , medicine , aspergillosis , drug resistance , aspergillus , sputum , gastroenterology , microbiology and biotechnology , immunology , antifungal , biology , dermatology , pathology , tuberculosis
Summary Background Chronic pulmonary aspergillosis (CPA) is a progressive respiratory disease, caused most commonly by A fumigatus, with significant morbidity and mortality. Azole resistance in A fumigatus is a growing concern worldwide, with resistance to itraconazole reported in up to 50% of patients. Aim The aim of this study was to determine whether a positive Aspergillus PCR (polymerase chain reaction) is a marker of resistance in CPA patients on azole therapy. Methods Patients were selected via a consecutive database search for the first 50 CPA patients with a positive Aspergillus PCR from January to September 2016. Data were collected regarding concurrent and subsequent culture results, current therapy and serum antifungal levels. PCR‐positive patients not on therapy were included as the control group. Results Twenty‐three patients were on therapy (15 itraconazole, 4 voriconazole and 4 posaconazole). Cycle threshold (Ct) values ranged from 20.8 to 37.9; no significant difference was found between each treatment and the control group ( P = .47). In treated patients, concurrent azole‐resistant A fumigatus was found in 75% of A fumigatus ‐positive cultures (6/8). All of the resistant isolates in the itraconazole group showed therapy resistance. Twenty per cent of all itraconazole levels were sub‐therapeutic. No significant difference was found in serum itraconazole levels for patients on itraconazole with a positive PCR versus negative PCR ( P = .44). Conclusion Positive sputum, Aspergillus ‐specific PCR can be associated with azole resistance in CPA patients on therapy.