Understanding the impact of antibiotics on bacterial metabolism is crucial for elucidating their mechanisms of action and developing more effective therapeutic strategies. β-lactam antibiotics, distinguished by their distinctive β-lactam ring structure, are widely used as antimicrobial agents. This study investigates the global metabolic alterations induced by three β-lactam antibiotics-meropenem (a carbapenem), ampicillin (a penicillin), and ceftazidime (a cephalosporin)-in Escherichia coli. Our comprehensive metabolic profiling revealed significant perturbations in bacterial metabolism, particularly in pathways such as glutathione metabolism, pantothenate and CoA biosynthesis, pyrimidine metabolism, and purine metabolism. Antibiotic treatment markedly increased reactive oxygen species levels, with meropenem reaching nearly 200 ± 7%, ampicillin at 174 ± 11%, and ceftazidime at 152 ± 7%. Additionally, β-lactam antibiotics elevated 8-OHdG levels to 4.73 ± 0.56-fold for meropenem, 2.49 ± 0.19-fold for ampicillin, and 3.19 ± 0.34-fold for ceftazidime; 8-OHG levels increased to 5.57 ± 0.72-fold for meropenem, 3.08 ± 0.31-fold for ampicillin, and 4.45 ± 0.66-fold for ceftazidime, indicating that oxidative stress enhances oxidative damage to bacterial DNA and RNA. Notably, we observed a selective upregulation of specific amino acids associated with cellular repair mechanisms, indicating a metabolic adaptation to counteract oxidative damage. These findings illustrate that β-lactam antibiotics induce a complex metabolic perturbations associated with ROS production, potentially compromising critical cellular components. This study enhances our understanding of the intricate relationship between antibiotic action and bacterial metabolism, providing valuable insights for developing effective strategies against antibiotic-resistant pathogens.

Hu sheep, a locally bred species in China known for its high productivity, is currently suffering from pneumonia. Here, we combine high-throughput 16SrRNA gene sequencing and bacterial culturing to examine the bacterial community in pneumonic Hu Sheep lungs (p < 0.05). The results showed that the abundance and diversity of lung bacteria in healthy sheep were significantly higher than those in pneumonia sheep (p = 0.139), while there was no significant difference between moderate and severe pneumonia. Furthermore, the composition of the lung microbiota community underwent significant alterations between different levels of pneumonia severity. The application of LEfSe analysis revealed a notable enrichment of Mannheimiae within the lungs of sheep afflicted with moderate pneumonia (p < 0.01), surpassing the levels observed in their healthy counterparts. Additionally, Fusobacterium emerged as the prevailing bacterial group within the lungs of sheep suffering from severe pneumonia. Integrating the results of bacterial isolation and identification, we conclusively determined that Mannheimia haemolytica was the primary pathogenic bacterium within the lungs of sheep afflicted with moderate pneumonia. Furthermore, the exacerbation of pneumonia may be attributed to the synergistic interplay between Fusobacterium spp. and other bacterial species. Our results provide new insights for guiding preventive and therapeutic measures for pneumonia of different severities in sheep.

The emergence of drug-resistant Enterobacteriaceae carrying plasmid-mediated β-lactamase genes has become a significant threat to public health. Organisms in the Enterobacteriaceae family containing New Delhi metallo-β-lactamase‑1 (NDM-1) and its variants, which are capable of hydrolyzing nearly all β-lactam antibacterial agents, including carbapenems, are referred to as superbugs and distributed worldwide. Despite efforts over the past decade, the discovery of an NDM-1 inhibitor that can reach the clinic remains a challenge. Here, we identified oxidized glutathione (GSSG) as a metabolic biomarker for bla _NDM-1 using a non-targeted metabolomics approach and demonstrated that GSSG supplementation could restore carbapenem susceptibility in Escherichia coli carrying bla _NDM-1 in vitro and in vivo. We showed that exogenous GSSG promotes the bactericidal effects of carbapenems by interfering with intracellular redox homeostasis and inhibiting the expression of NDM-1 in drug-resistant E. coli . This study establishes a metabolomics-based strategy to potentiate metabolism-dependent antibiotic efficacy for the treatment of antibiotic-resistant bacteria.

This study comprehensively explored the epidemiology, virulence, antibiotic resistance, and genomic features of ovine-derived Mannheimia haemolytica across three provinces in Northwest China (Gansu, Ningxia, and Shaanxi). Lung tissue samples were collected postmortem from sheep with respiratory disease (nine per province), cultured under sterile conditions, and screened by morphological, Gram staining, PCR, and NGS methods. Nine M. haemolytica strains were successfully isolated (isolation rate 33.33%) and identified as serotypes A1, A2, and A6, with Shaanxi exhibiting a significantly higher isolation rate of 66.67%. Genomic analysis revealed that each isolate each harbored over 100 virulence genes and displayed notable genetic diversity. In murine assays, intraperitoneal inoculation in mice caused severe breathing problems and death within 24 h; necropsy revealed lung congestion, splenic necrosis foci, and hepatic congestion. Antibiotic susceptibility testing showed sensitivity to ciprofloxacin, azithromycin, gentamicin, and levofloxacin, while resistance was observed for tiamulin and enrofloxacin. These findings indicate a high prevalence and strong pathogenicity of ovine M. haemolytica in Shaanxi, underscore the presence of key resistance traits, and provide a genomic and pathogenic reference to guide region-specific surveillance, therapeutic decisions, and vaccine-oriented control in small ruminant herds. Importantly, these results highlight the need for region-specific monitoring and judicious antibiotic use, which are essential to forestall the spread of resistant strains and to ensure sustainable disease management strategies.

The escalation of antibiotic resistance constitutes a significant global health crisis, urgently demanding innovative strategies to restore and amplify the effectiveness of our existing antimicrobial arsenal. This review systematically explores the diverse landscape of antibiotic adjuvants, beginning with an elucidation of their classifications and profound mechanisms of action. We meticulously detail various categories of these agents, encompassing both synthetic compounds and naturally derived molecules, highlighting their crucial functions in potentiating antibiotic activity through mechanisms such as enhancing bacterial cell permeability, modulating the expression of resistance-conferring genes and optimizing drug–target interactions. Furthermore, we critically assess current screening methodologies, particularly the advancements in high-throughput approaches, and their implications for the identification and validation of novel adjuvant candidates. The review underscores the potential of antibiotic adjuvants as a promising frontier in our global endeavor to overcome bacterial resistance and ensure the sustained utility of antimicrobial medicine.