Xiaoqian Long,Feng Lin,Biao Tang,Fengcheng Miao,Zhiyu Li,Yao Shen,Hua Yang,Jiangang Ma
Objectives Acinetobacter indicus is an important pathogen of nosocomial infection. The purpose of this study was to analyze the resistance and transmission of A. indicus strain AIBD14 isolated from slaughterhouse environment. Methods A total of 96 environmental samples were collected from slaughterhouse. The antimicrobial susceptibility test was carried out by microbroth dilution method and E -test. Whole genome sequencing and bioinformatics analysis of the AIBD14 were performed, then S1-PFGE and southern blot verified the location of bla NDM-1 and tet (X6). Results The AIBD14 is resistant to meropenem but susceptibility to tigecycline, and coharboring bla NDM-1 and tet (X6). The bla NDM-1 is located on the pAIBD14-NDM-1 that cannot be transferred by conjugation. Specifically, bla NDM-1 is located on the transposon Tn 125 , and bla NDM-1 can be transferred to other species with the help of transposon. The genetic background of bla NDM-1 is "IS Aba125 - bla NDM-1 - ble MEL - dsbD - cutA - groES - groEL -insE-IS Aba125 ". pAIBD14-NDM-1 is classified into the GR31 plasmid based on the homology of the repB . Meanwhile, there are two XerC/D-like binding sites on the plasmid, which can mediate the transfer of resistance genes. The tet (X6) gene is located on the chromosome of AIBD14, its downstream is accompanied by the neglected macrolide resistance gene estT , and there is a single copy of the insertion element IS CR2 around tet (X6) as the genetic background "IS Aba4 -IS 3 -hp-hp- tet (X6)- estT - guaA -IS CR2 ". Conclusions This is the first report of the coexistence of tet (X6) and bla NDM-1 in the A. indicus , and it has the risk of horizontal transfer across multiple species. So strict monitoring the multiple-resistant bacteria in the industrial chain is necessary based on the "One Heath".
Shijie Yao,Yaru Hu,Jianfeng Ye,Jianhao Xie,Xuetao Zhao,Lingli Liu,Shuguang Lyu,Kuangfei Lin,Changzheng Cui
The super-resistant bacteria that produce the New Delhi metallo-β-lactamase 1 (NDM-1) enzyme are becoming a conceivably major worldwide clinical issue with serious consequences. Studying the disinfection and mechanism of super-resistant bacteria and their antibiotic resistance genes (ARGs) is crucial for controlling their spread in the water environment. In this study, the disinfection of the super-resistant bacterium Acinetobacter sp. CS-2 and its transferable ARGs (plasmid-encoded bla NDM-1 and bla OXA-58 ) by ultraviolet radiation (UV), peroxymonosulfate (PMS), and ultraviolet/peroxymonosulfate (UV/PMS) exposure were investigated. UV/PMS could completely inactivate CS-2 and control the photoreactivation risk, while bacteria that underwent UV and PMS treatment had survival ratios of 0.22% and 0.28%, respectively. The removal efficiencies of bla NDM-1 and bla OXA-58 ranged from 3.64 to 4.05 log, and the advantage of UV/PMS treatment on ARGs damage was further identified by gel electrophoresis analysis. The removal efficiency of bla NDM-1 was lower than that of bla OXA-58 , which was attributed to the low number of adjacent 5′-TT-3′ harbored by bla NDM-1 . The removal rate constants of the ARGs by UV treatment were significantly correlated with the number of adjacent base pairs (e.g., 5′-TT-3′, 5′-CT-3′, 5′-TC-3′ and 5′-CC-3′) and length, with R -values ranging from 0.9044 to 0.9512. Singlet oxygen ( 1 O 2 ) played a vital role in the reduction of bla NDM-1 and bla OXA-58 in the UV/PMS treatment. UV/PMS showed high removal efficiency under natural pH conditions and in the presence of various aqueous ions (e.g., Cl − , SO 4 2− and HCO 3 − ). Overall, this study provides new understandings and theoretical support for the risk control of super-resistant bacteria and plasmid-encoded ARGs.
Yali Zhang,Mengyue Liu,Jiangfeng Zhang,Jie Wu,Lijuan Hong,LiQiang Zhu,Jinzhao Long
bla NDM-1 and bla KPC-2 are responsible for the global increase in carbapenem-resistant Klebsiella pneumoniae , posing a great challenge to public health. However, the impact of phylogenetic factors on the dissemination of bla NDM-1 and bla KPC-2 is not yet fully understood . This study established a global dataset of 4051 bla NDM-1 + and 10,223 bla KPC-2 + K. pneumoniae genomes, and compared their transmission modes on a global scale. The results showed that bla NDM-1 + K. pneumoniae genomes exhibited a broader geographical distribution and higher sequence type (ST) richness than bla KPC-2 + genomes, indicating higher transmissibility of the bla NDM-1 gene. Furthermore, bla NDM-1 + genomes displayed significant differences in ST lineage, antibiotic resistance gene composition, virulence gene composition and genetic environments compared with bla KPC-2 + genomes, suggesting distinct dissemination mechanisms. bla NDM-1 + genomes were predominantly associated with ST147 and ST16, whereas bla KPC-2 + genomes were mainly found in ST11 and ST258. Significantly different accessory genes were identified between bla NDM-1 + and bla KPC-2 + genomes. The preference for bla KPC-2 distribution across certain countries, ST lineages and genetic environments underscores vertical spread as the primary mechanism driving the expansion of bla KPC-2 . In contrast, bla NDM-1 + genomes did not display such a strong preference, confirming that the dissemination of bla NDM-1 mainly depends on horizontal gene transfer. Overall, this study demonstrates different phylogenetic drivers for the dissemination of bla NDM-1 and bla KPC-2 , providing new insights into their global transmission dynamics.
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