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Hussin A, Nathan S, Shahidan MA, Nor Rahim MY, Zainun MY, Khairuddin NAN, Ibrahim N. Identification and mechanism determination of the efflux pump subunit amrB gene mutations linked to gentamicin susceptibility in clinical Burkholderia pseudomallei from Malaysian Borneo. Mol Genet Genomics 2024; 299:12. [PMID: 38381232 DOI: 10.1007/s00438-024-02105-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 12/29/2023] [Indexed: 02/22/2024]
Abstract
The bacterium Burkholderia pseudomallei is typically resistant to gentamicin but rare susceptible strains have been isolated in certain regions, such as Thailand and Sarawak, Malaysia. Recently, several amino acid substitutions have been reported in the amrB gene (a subunit of the amrAB-oprA efflux pump gene) that confer gentamicin susceptibility. However, information regarding the mechanism of the substitutions conferring the susceptibility is lacking. To understand the mechanism of amino acid substitution that confers susceptibility, this study identifies the corresponding mutations in clinical gentamicin-susceptible B. pseudomallei isolates from the Malaysian Borneo (n = 46; Sarawak: 5; Sabah: 41). Three phenotypically confirmed gentamicin-susceptible (GENs) strains from Sarawak, Malaysia, were screened for mutations in the amrB gene using gene sequences of gentamicin-resistant (GENr) strains (QEH 56, QEH 57, QEH20, and QEH26) and publicly available sequences (AF072887.1 and BX571965.1) as the comparator. The effect of missense mutations on the stability of the AmrB protein was determined by calculating the average energy change value (ΔΔG). Mutagenesis analysis identified a polymorphism-associated mutation, g.1056 T > G, a possible susceptible-associated in-frame deletion, Delta V412, and a previously confirmed susceptible-associated amino acid substitution, T368R, in each of the three GENs isolates. The contribution of Delta V412 needs further confirmation by experimental mutagenesis analysis. The mechanism by which T368R confers susceptibility, as elucidated by in silico mutagenesis analysis using AmrB-modeled protein structures, is proposed to be due to the location of T368R in a highly conserved region, rather than destabilization of the AmrB protein structure.
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Affiliation(s)
- Ainulkhir Hussin
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
- Department of Pathology, Queen Elizabeth Hospital, Ministry of Health Malaysia, Kota Kinabalu, Sabah, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Muhammad Ashraf Shahidan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Mohd Yusof Nor Rahim
- Department of Pathology, Queen Elizabeth Hospital, Ministry of Health Malaysia, Kota Kinabalu, Sabah, Malaysia
| | - Mohamad Yusof Zainun
- Department of Pathology, Queen Elizabeth Hospital, Ministry of Health Malaysia, Kota Kinabalu, Sabah, Malaysia
| | | | - Nazlina Ibrahim
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
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Melioidosis and Burkholderia pseudomallei : progress in epidemiology, diagnosis, treatment and vaccination. Curr Opin Infect Dis 2022; 35:517-523. [PMID: 35942848 DOI: 10.1097/qco.0000000000000869] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Melioidosis and its causative bacterium Burkholderia pseudomallei are being found in unexpected locations and bacterial genotyping is providing new insights into global spread and where and how individuals are being infected. This review summarizes recent studies covering the epidemiology, diagnosis, treatment, and prevention of melioidosis. RECENT FINDINGS Whole-genome sequencing of B. pseudomallei from patients and environmental sampling is informing the phylogeography of B. pseudomallei at regional, continental, and global levels, while also defining the epidemiology for individual cases. The situation in Africa remains the most unresolved, while the evolving story of B. pseudomallei in the Americas may establish that B. pseudomallei is endemic in parts of southern USA. Guidelines for diagnosis and treatment of melioidosis are well established, and published mortality has decreased from 50% or higher to 10% or lower in some countries but access to laboratory and therapeutic resources are not available or are extremely limited in many melioidosis-endemic regions. SUMMARY The enormous clinical diversity of melioidosis and the complexities of laboratory diagnosis and of treatment make it a sentinel disease for highlighting the continuing global disparities in access to and provision of healthcare.
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