Characterization of Ceftazidime Resistance Mechanisms in Clinical Isolates of Burkholderia pseudomallei from Australia
| Autor: | Bart J. Currie, David M. Wagner, Derek S. Sarovich, Lindsey M. Watson, David M. Engelthaler, Meagan L. Seymour, Mark Mayo, James M. Cook, Alex T. Von Schulze, Leisha J. Richardson, Erin P. Price, Apichai Tuanyok, Talima Pearson, Sharon J. Peacock, Paul Keim |
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| Rok vydání: | 2012 |
| Předmět: |
Bacterial Diseases
Burkholderia pseudomallei Melioidosis lcsh:Medicine Ceftazidime Microbial Sensitivity Tests Drug resistance Gene mutation Microbiology Molecular Genetics Gene Knockout Techniques 03 medical and health sciences Antibiotic resistance Drug Resistance Bacterial Genetics medicine Humans lcsh:Science Biology 030304 developmental biology Evolutionary Biology 0303 health sciences Antiinfective agent Multidisciplinary Population Biology biology 030306 microbiology lcsh:R Genetic Complementation Test Australia Computational Biology Sequence Analysis DNA biology.organism_classification medicine.disease Anti-Bacterial Agents 3. Good health Infectious Diseases Burkholderia Genes Bacterial Mutation Medicine lcsh:Q Population Genetics Research Article medicine.drug |
| Zdroj: | PLoS ONE PLoS ONE, Vol 7, Iss 2, p e30789 (2012) |
| ISSN: | 1932-6203 |
| DOI: | 10.1371/journal.pone.0030789 |
| Popis: | Burkholderia pseudomallei is a gram-negative bacterium that causes the serious human disease, melioidosis. There is no vaccine against melioidosis and it can be fatal if not treated with a specific antibiotic regimen, which typically includes the third-generation cephalosporin, ceftazidime (CAZ). There have been several resistance mechanisms described for B. pseudomallei, of which the best described are amino acid changes that alter substrate specificity in the highly conserved class A β-lactamase, PenA. In the current study, we sequenced penA from isolates sequentially derived from two melioidosis patients with wild-type (1.5 µg/mL) and, subsequently, resistant (16 or ≥256 µg/mL) CAZ phenotypes. We identified two single-nucleotide polymorphisms (SNPs) that directly increased CAZ hydrolysis. One SNP caused an amino acid substitution (C69Y) near the active site of PenA, whereas a second novel SNP was found within the penA promoter region. In both instances, the CAZ resistance phenotype corresponded directly with the SNP genotype. Interestingly, these SNPs appeared after infection and under selection from CAZ chemotherapy. Through heterologous cloning and expression, and subsequent allelic exchange in the native bacterium, we confirmed the role of penA in generating both low-level and high-level CAZ resistance in these clinical isolates. Similar to previous studies, the amino acid substitution altered substrate specificity to other β-lactams, suggesting a potential fitness cost associated with this mutation, a finding that could be exploited to improve therapeutic outcomes in patients harboring CAZ resistant B. pseudomallei. Our study is the first to functionally characterize CAZ resistance in clinical isolates of B. pseudomallei and to provide proven and clinically relevant signatures for monitoring the development of antibiotic resistance in this important pathogen. |
| Databáze: | OpenAIRE |
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