Functional characterization and phylogenetic analysis of acquired and intrinsic macrolide phosphotransferases in the Bacillus cereus group |
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| Authors: | Chao Wang Zhihai Sui Sébastien Olivier Leclercq Gang Zhang Meilin Zhao Weiqi Chen Jie Feng |
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| Institution: | 1. State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China;2. School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu, China;3. Department of Environmental and Biological Pharmaceutical, Beijing Industrial Technician College, Beijing, China;4. Beijing Key Laboratory of Microbial Drug Resistance and Resistome, Beijing, China |
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| Abstract: | The Bacillus cereus group is composed of Gram‐positive spore‐forming bacteria of clinical and ecological importance. More than 200 B. cereus group isolates have been sequenced. However, there are few reports of B. cereus group antibiotic resistance genes. This study identified two functional classes of macrolide phosphotransferases (Mphs) in the B. cereus group. Cluster A Mphs inactivate 14‐ and 15‐membered macrolides while Cluster B Mphs inactivate 14‐, 15‐ and 16‐membered compounds. The genomic region surrounding the Cluster B Mph gene is related to various plasmid sequences, suggesting that this gene is an acquired resistance gene. In contrast, the Cluster A Mph gene is located in a chromosomal region conserved among all B. cereus group isolates, and data indicated that it was acquired early in the evolution of the group. Therefore, the Cluster A gene can be considered an intrinsic resistance gene. However, the gene itself is not present in all strains and our comparative genomics analyses showed that it is exchanged among strains of the B. cereus group by the mean of homologous recombination. These results provide an alternative mechanism to intrinsic resistance. |
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