Microbiology Spectrum
·
2023
·Vol. 11
·期 4
·
IF 3.7
Ya-Jun Zhai,Pei-Yi Liu,Xing-Wei Luo,Jun Liang,Ya-Wei Sun,Xiao-Die Cui,Dan-Dan He,Yu-Shan Pan,Hua Wu,Gong-Zheng Hu
With the increasing and inappropriate use of colistin, the emerging colistin-resistant isolates have been frequently reported during the last few decades. Therefore, new potential targets and adjuvants to reverse colistin resistance are urgently needed. Our previous study has confirmed a marked increase of colistin susceptibility (16-fold compared to the wild-type Salmonella strain) of cpxR overexpression strain JSΔacrBΔcpxR::kan/pcpxR (simplified as JSΔΔ/pR). To searching for potential new drug targets, the transcriptome and metabolome analysis were carried out in this study. We found that the more susceptible strain JSΔΔ/pR displayed striking perturbations at both the transcriptomics and metabolomics levels. The virulence-related genes and colistin resistance-related genes (CRRGs) were significantly downregulated in JSΔΔ/pR. There were significant accumulation of citrate, α-ketoglutaric acid, and agmatine sulfate in JSΔΔ/pR, and exogenous supplement of them could synergistically enhance the bactericidal effect of colistin, indicating that these metabolites may serve as potential adjuvants for colistin therapy. Additionally, we also demonstrated that AcrB and CpxR could target the ATP and reactive oxygen species (ROS) generation, but not proton motive force (PMF) production pathway to potentiate antibacterial activity of colistin. Collectively, these findings have revealed several previously unknown mechanisms contributing to increased colistin susceptibility and identified potential targets and adjuvants for potentiating colistin treatment of Salmonella infections.IMPORTANCE Emergence of multidrug-resistant (MDR) Gram-negative (G-) bacteria have led to the reconsideration of colistin as the last-resort therapeutic option for health care-associated infections. Finding new drug targets and strategies against the spread of MDR G- bacteria are global challenges for the life sciences community and public health. In this paper, we demonstrated the more susceptibility strain JSΔΔ/pR displayed striking perturbations at both the transcriptomics and metabolomics levels and revealed several previously unknown regulatory mechanisms of AcrB and CpxR on the colistin susceptibility. Importantly, we found that exogenous supplement of citrate, α-ketoglutaric acid, and agmatine sulfate could synergistically enhance the bactericidal effect of colistin, indicating that these metabolites may serve as potential adjuvants for colistin therapy. These results provide a theoretical basis for finding potential new drug targets and adjuvants.
研究领域:
微生物学
·
药理学
·
感染病学
✓ 已验证
DOI
PubMed
高影响因子
INFECTION GENETICS AND EVOLUTION
·
2025
·
IF 2.6
Huanhuan Zhang,Fengjun Sun,Wei Feng,Yan Qian
Objectives This study investigated the mechanisms underlying polymyxin B (PMB)-induced resistance and examined the role of PMB in combination with amikacin (AMK) in delaying the development of resistance. Methods In vitro continuous induction of three Klebsiella pneumoniae strains was performed using PMB alone or in combination with AMK, and variations in the minimum inhibitory concentration (MIC) were determined via the microdilution method. The Kp81 strain, which presented the most significant delay in resistance development, was selected for analysis of the expression of relevant genes via qRT–PCR. Homologous recombination techniques were employed to construct nlpE and cpxR gene knockout and complemented Kp81 strains, and the expression levels of these genes, as well as changes in the MIC following continuous induction, were assessed. Additionally, the biofilm-forming abilities of the strains were analyzed via crystal violet staining and confocal laser scanning microscopy. Results The results indicate that the combination of PMB and AMK can delay the development of resistance to PMB in K. pneumoniae . qRT–PCR analysis demonstrated a significant increase in the expression of phoP , nlpE , cpxR , and acrA in the resistant strain Kp81·R, whereas these genes were significantly downregulated in the resistant delay strain Kp81·DR. Notably, after 20 h of PMB treatment, the expression of nlpE was markedly elevated in the nlpE knockout strain. cpxR exhibited synchronized dynamic changes with nlpE in both the nlpE knockout and complemented strains, whereas acrA showed a similar expression pattern in the cpxR knockout and complemented strains. Additionally, the absence of nlpE or cpxR was found to delay PMB resistance. Furthermore, biofilm formation was significantly increased in both the resistant strains and those treated with PMB, while the combination of PMB with AMK inhibited biofilm formation. Conclusions The combination of PMB and AMK can delay the development of resistance in K. pneumoniae to PMB. The nlpE gene, as a key regulatory factor, can influence PMB resistance by modulating the CpxA/R two-component system and biofilm formation.
研究领域:
微生物学
·
药理学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
mSystems
·
2022
·
IF 7.324
Zhe Zhao,Ying Xu,Bo Jiang,Qingsheng Qi,Ya-Jie Tang,Mo Xian,Jichao Wang,Guang Zhao
The two-component system CpxRA can sense environmental stresses and regulate transcription of a wide range of genes for the purpose of adaptation. Despite extensive research on this system, the identification of the CpxR regulon is not systematic or comprehensive. Herein, genome-wide screening was performed using a position-specific scoring matrix, resulting in the discovery of more than 10,000 putative CpxR binding sites, which provides an extensive and selective set of targets based on sequence. More than half of the candidate genes ultimately selected (73/97) were experimentally confirmed to be CpxR-regulated genes through experimental analysis. These genes are involved in various physiological functions, indicating that the CpxRA system regulates complex cellular processes. The study also found for the first time that the CpxR-regulated genes ydeE, xylE, alx, and galP contribute to Escherichia coli resistance to acid stress, whereas prlF, alx, casA, yacH, ydeE, sbmA, and ampH contribute to E. coli resistance to cationic antimicrobial peptide stress. Among these CpxR-regulated genes, ydeE and alx responded to both stressors. In a similar way, a cationic antimicrobial peptide is capable of directly activating the periplasmic domain of CpxA kinase in vitro, which is consistent with the CpxA response to acid stress. These results greatly expand our understanding of the CpxRA-dependent stress response network in E. coli.IMPORTANCE CpxRA system is found in many pathogens and plays an essential role in sensing environmental signals and transducing information inside cells for adaptation. It usually regulates expression of specific genes in response to different environmental stresses and is important for bacterial pathogenesis. However, systematically identifying CpxRA-regulated genes and elucidating the regulative role of CpxRA in bacteria responding to environmental stress remains challenging. This study discovered more than 10,000 putative CpxR binding sites based on sequence. This bioinformatics approach, combined with experimental assays, allowed the identification of many previously unknown CpxR-regulated genes. Among the novel 73 CpxRA-regulated genes identified in this study, the role of nine of them in contributing to E. coli resistance to acid or cationic antimicrobial peptide stress was studied. The potential correlation between these two environmental stress responses provides insight into the CpxRA-dependent stress response network. This also improves our understanding of environment-bacterium interaction and Gram-negative pathogenesis.
研究领域:
微生物学
·
分子生物学
·
细菌致病机制
·
基因组学
·
生物信息学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）