Optimizing macrolide resistance detection for : a potential low-cost, time-saving alternative.
Journal
Microbiology spectrum
Journal Volume
13
Journal Issue
10
ISSN
2165-0497
Date Issued
2025-10-07
Author(s)
Abstract
complex (MABC) is notoriously difficult to treat. Current guidelines suggest a 14-day-long incubation and/or sequencing of to detect inducible macrolide resistance. We assessed whether the evolution of minimum inhibitory concentrations (MICs) can reliably predict inducible macrolide resistance and clinical outcomes of extrapulmonary MABC infections. Between 2013 and 2015, isolates were identified from extrapulmonary sites at a medical center. Drug susceptibility testing (DST) was conducted with results read on D3, D7, and D14. A fourfold or more increase in clarithromycin MIC between D3 and D7 was used to predict inducible macrolide resistance. The results were compared with the genotypic prediction of DST using sequencing of and . Clinical data were reviewed. Thirty-five unique isolates comprising 16 subsp. , 18 subsp. and 1 subsp. were identified. The overall inducible macrolide resistance was 40%. Using the proposed prediction rule, the sensitivity and specificity were 81% and 100%, while using genotypic prediction, the sensitivity and specificity were 75% and 100%, respectively. From the chart review, 28 patients received treatment, among whom 18 had evaluable outcomes. Most (92.9%) of the patients received macrolide-based combinatorial treatment; 71.4% of them received surgery. Of the outcome-evaluable patients, 77.8% had favorable outcomes. Our preliminary study highlighted that susceptibility testing read within one week holds promising potential for detecting inducible macrolide resistance. Further validation with larger cohorts of pulmonary and extrapulmonary disease is warranted.IMPORTANCEDrug susceptibility testing for difficult-to-treat microorganisms like is frequently unavailable due to costs and technical demands. We propose a potential low-cost, time-saving alternative, using interval minimum inhibitory concentration evolution to predict the final phenotypic results. Our preliminary findings suggest comparable performance of the proposed early prediction method to the gold standard and the genotypic prediction in our small, extrapulmonary complex collections. Given its promising potential, validation in a larger cohort with pulmonary disease is needed for wider clinical application.
Subjects
Mycobacterium abscessus
Taiwan
anti-bacterial agents
macrolides
microbial sensitivity tests
SDGs
Type
journal article