TALENT EDUCATION

Chinese scholars have discovered a new lincomycin resistance gene


At present, antibiotic resistance in bacteria has become one of the most concerned issues in human medicine and animal medicine. As an important poultry pathogen, Riemerella duck plague can cause infectious seromanitis in a variety of poultry, which often brings huge economic losses to the poultry industry.
Recently, the team of Professor Cheng Anchun of Sichuan Agricultural University published a research paper online in Science of The Total Environment, reporting the discovery of a new lincomycin resistance gene lnu(I), and revealing the function, potential origin and transmission mechanism of this gene.
In this study, it was found that the sequence identity of Lnu(I) was less than 66% with the currently known lnu gene, and that lincomycin (MIC=128mg/L) and clindamycin (MIC=2mg/L) resistance were mediated by Riemerella susceptible strains of duck plague, and the encoded protein could inactivate lincomycin and clindamycin through adenyylation in vitro, which was an unreported new lincosamide resistance gene. Epidemiological investigation showed that the olnu(I) gene positive strain could be detected in the Isolates of Riemerella duck plague in 8 provinces including Sichuan, Anhui and Shandong in China, and the earliest strain isolated in 2011 could be traced. Further genomic epidemiological analysis revealed that 56 lnu(I) sequences were identified on chromosomes or plasmids of as many as 36 different species of bacteria, and these bacteria were mainly derived from environmentally isolated strains.
The team further showed that members of the Flavobacterae family were the main carriers of the lnu(I) gene, and that the Flavobacterium chromosomes in the environment (sludge and freshwater) had similar GC content and stable genetic background to the lnu(I) gene. Notably, lnu(I) genes associated with insert sequences (IS) and integration-binding elements (ICEs) have been detected in pathogens of human and animal origin.

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Lnu(I) Analysis of the origin of proteins

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lnu(I) Movable genetic elements in the genetic environment Courtesy of Sichuan Agricultural University
These results suggest that the bacteria of the genus Flavobacterium in the environment may be a potential ancestral source of the lnu(I) gene, and have undergone lateral gene transfer to pathogenic bacteria. This study revealed the functional characteristics of the novel lincosamide resistance gene lnu(I), and explored its potential origin and transmission mechanism through genomic epidemiological methods, providing new insights for the study of lincosamide resistance mechanism.
Related Paper Information:https://doi.org/10.1016/j.scitotenv.2023.167400



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