Background: Tuberculosis (TB) continues to pose a threat to communities worldwide and remains a significant public health issue in several countries. We assessed the role of heteroresistance and efflux pumps in bedaquiline (BDQ)-resistant Mycobacterium tuberculosis isolates.
Methods: Nineteen clinical isolates were included in the study, of which fifteen isolates were classified as MDR or XDR, while four isolates were fully susceptible. To evaluate BDQ heteroresistance, the Microplate Alamar Blue Assay (MABA) method was employed. For screening mixed infections, MIRU-VNTR was performed on clinical isolates. Mutations in the atpE and Rv0678 genes were determined based on next-generation sequencing data. Additionally, real-time PCR was applied to assess the expression of efflux pump genes in the absence and presence of verapamil (VP).
Results: All 15 drug-resistant isolates displayed resistance to BDQ. Among the 19 total isolates, 21.05% (4/19) exhibited a heteroresistance pattern to BDQ. None of the isolates carried a mutation of the atpE and Rv0678 genes associated with BDQ resistance. Regarding the MIRU-VNTR analysis, most isolates (94.73%) showed the Beijing genotype. Fifteen (78.9%) isolates showed a significant reduction in BDQ MIC after VP treatment. The efflux pump genes of Rv0676c, Rv1258c, Rv1410c, Rv1634, Rv1819, Rv2459, Rv2846, and Rv3065 were overexpressed in the presence of BDQ.
Conclusions: Our results clearly demonstrated the crucial role of heteroresistance and efflux pumps in BDQ resistance. Additionally, we established a direct link between the Rv0676c gene and BDQ resistance. The inclusion of VP significantly reduced the MIC of BDQ in both drug-susceptible and drug-resistant clinical isolates.
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http://dx.doi.org/10.1186/s12941-024-00694-3 | DOI Listing |
J Antimicrob Chemother
December 2024
Department of Microbiology, School of Medicine, Sungkyunkwan University, Suwon, Republic of Korea.
Background: Heteroresistance, frequently observed in diverse bacterial species, imposes clinical challenges. For this study, we investigated the stability and resilience of tigecycline heteroresistance in Acinetobacter baumannii.
Methods: Four tigecycline-heteroresistant (HR) A.
BMC Microbiol
July 2024
Faculty of Pharmacy, Department of Microbiology and Immunology, Helwan University, P. O. Box: 11795, Ain-Helwan, Cairo, 01060564729, Egypt.
Microbiol Res
October 2024
Department of Biotechnology, College of Basic Medical Science, Dalian Medical University, Dalian 116044, China; Liaoning Provincial Core Lab of Medical Molecular Biology, Dalian Medical University, Dalian 116044, China. Electronic address:
Tigecycline and the newly Food and Drug Administration-approved tetracyclines, including eravacycline and omadacycline, are regarded as last-resort treatments for multidrug-resistant Enterobacterales. However, tigecycline resistance in Klebsiella pneumoniae has increased, especially the underlying mechanism of heteroresistance is unclear. This study aimed to elucidate the mechanisms underlying tigecycline resistance and heteroresistance in clinical K.
View Article and Find Full Text PDFAntimicrob Agents Chemother
August 2024
Division of Infectious Diseases, Houston Methodist Hospital, Houston, Texas, USA.
The siderophore-cephalosporin cefiderocol (FDC) presents a promising treatment option for carbapenem-resistant (CR) (PA). FDC circumvents traditional porin and efflux-mediated resistance by utilizing TonB-dependent receptors (TBDRs) to access the periplasmic space. Emerging FDC resistance has been associated with loss of function mutations within TBDR genes or the regulatory genes controlling TBDR expression.
View Article and Find Full Text PDFAnn Clin Microbiol Antimicrob
April 2024
Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave., Jomhoori St, Tehran, 1316943551, Iran.
Background: Tuberculosis (TB) continues to pose a threat to communities worldwide and remains a significant public health issue in several countries. We assessed the role of heteroresistance and efflux pumps in bedaquiline (BDQ)-resistant Mycobacterium tuberculosis isolates.
Methods: Nineteen clinical isolates were included in the study, of which fifteen isolates were classified as MDR or XDR, while four isolates were fully susceptible.
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