The development of drug-resistance in the opportunistic pathogen Escherichia coli has become a global public health concern. Due to the share of similar flora between pets and their owners, the detection of pet-origin antibiotic-resistant E. coli is necessary. This study aimed to detect the prevalence of feline-origin ESBL E. coli in China and to explore the resistance elimination effect of garlic oil to cefquinome on ESBL E. coli. Cat fecal samples were collected from animal hospitals. The E. coli isolates were separated and purified by indicator media and polymerase chain reaction (PCR). ESBL genes were detected by PCR and Sanger sequencing. The MICs were determined. The synergistic effect of garlic oil and cefquinome against ESBL E. coli was investigated by checkerboard assays, time-kill and growth curves, drug-resistance curves, PI and NPN staining, and a scanning electronic microscope. A total of 80 E. coli strains were isolated from 101 fecal samples. The rate of ESBL E. coli was 52.5% (42/80). The prevailing ESBL genotypes in China were CTX-M-1, CTX-M-14, and TEM-116. In ESBL E. coli, garlic oil increased the susceptibility to cefquinome with FICIs from 0.2 to 0.7 and enhanced the killing effect of cefquinome with membrane destruction. Resistance to cefquinome decreased with treatment of garlic oil after 15 generations. Our study indicates that ESBL E. coli has been detected in cats kept as pets. The sensitivity of ESBL E. coli to cefquinome was enhanced by garlic oil, indicating that garlic oil may be a potential antibiotic enhancer.

Traditional Chinese Medicine (TCM) has a rich history spanning 2000 years. Shuanghuanglian, a traditional Chinese herbal formula composed of three botanicals, is primarily used to treat colds, respiratory infections (including bacterial pneumonia), and pharyngitis. Previous research has found that the volatile oil of Shuanghuanglian is crucial for its efficacy. However, there is a lack of studies investigating its mechanisms. This study aims to explore the antibacterial and anti-inflammatory mechanisms of Shuanghuanglian volatile oil and its potential to enhance the antibacterial effects when used in conjunction with antibiotics. Determination of the GC-MS fingerprint of SVO using Gas Chromatography-Mass Spectrometry (GC-MS), The antibacterial effects of SVO on multidrug-resistant Klebsiella pneumoniae (MDR-KP) were assessed by detecting MIC, checkerboard method assay, time-kill curves, resistance growth curves, transcriptome sequencing analysis, scanning electron microscopy(SEM), purification, and quantitative analysis of extracellular polysaccharides(EPS). In vivo part, an MDR-KP induced mouse pneumonia model was established to evaluate the mitigating effects of SVO on mouse pneumonia, using comprehensive network pharmacology and bioinformatics to identify genes related to bacterial pneumonia and potential targets of SVO. Validation was performed through molecular docking, qPCR, and ELISA tests. SVO modulates the expression of MDR-KP mRNA for wecB, wecC, murA, murD, murE, murF, inhibiting the synthesis of O-antigen polysaccharides and peptidoglycans, thereby compromising bacterial cell wall integrity and affecting the synthesis of biofilms. These actions not only exhibit antibacterial effects but also enhance antibacterial activity, restoring the sensitivity of CEF to MDR-KP. SVO suppresses the biological activity of PTGS2, reducing the production of Prostaglandin E2 (PGE2), thereby exerting antipyretic and anti-inflammatory effects, providing new insights for the development of natural non-steroidal anti-inflammatory drugs (NSAIDs). Our research indicates that SVO exerts antipyretic, anti-inflammatory, and antibacterial synergistic effects through multiple pathways.

Introduction: The development of extended-spectrum-beta-lactamase (ESBLs) Escherichia coli (E. coli) has become a global threat to public health. An alternative strategy to alleviate this is identifying potential natural compounds to restore antibiotic activity against ESBLs E. coli. This study aimed to find a possible compound to restore ESBLs E. coli sensitivity to ceftiofur.Methods: The synergistic effect of kaempferol and ceftiofur against ESBLs E. coli was investigated by checkerboard assays, time-kill, growth curves, and scanning electronic microscope. The impact of kaempferol with ceftiofur on the biofilm of ESBLs E. coli was evaluated by crystal violet staining and laser scanning confocal microscopy and this study also assessed the effect of kaempferol on the initial adhesion and aggregation of E. coli (SY20) by examining motility, adhesion, and surface characteristics. The RT-qPCR was used to determine the effect of kaempferol on the expression of genes related to the LuxS/AI-2 quorum sensing system in ESBLs E. coli, and the effect of kaempferol on AI-2 signaling molecules was determined by molecular docking and bioassay. The impact of kaempferol on the activity of bla_CTX-M-27 protein was determined by RT-qPCR, molecular docking, and nitrofen experiments, the results were further verified by transcriptome analysis. The mouse infection model was established, and the inhibitory mechanism of kaempferol with ceftiofur on bacteria in vivo was further verified by HE staining and immunohistochemistry.Results and discussion: Kaempferol with ceftiofur exerts synergistic antibacterial and bactericidal effects on ESBLs E. coli by influencing β-lactamase activity, biofilm formation, and LuxS/AI-2 QS system. In vivo, kaempferol protected the small intestinal villi from the damage of ESBLs E. coli. Furthermore, kaempferol fully restores the activity of ceftiofur in animal infection models by relieving the TLR₄/NF-κb pathway. In conclusion, the sensitivity of ESBLs E. coli to ceftiofur in vitro and in vivo could be enhanced by kaempferol, which showed that kaempferol may be a kind of antibiotic adjuvant.

Introduction: Calf diarrhea is one of the most common diseases causing significant economic losses in the livestock industry. This article aims to investigate the bacterial causes of calf diarrhea in the Ningxia region and to evaluate the synergistic antibacterial effect of Chinese Herbal Formula (CHF) and Microcin J25 (MccJ25) on pathogenic bacteria, as well as its clinical prevention and treatment effects on calf diarrhea.Methods: A total of 100 diarrheic fecal samples were collected from calves across 10 cattle farms in the Ningxia region. Bacterial isolation and identification were performed to detect E. coli and Salmonella strains. The in vitro synergistic antibacterial effects of a Chinese Herbal Formula (CHF) combined with Microcin J25 (MccJ25) were evaluated using antimicrobial susceptibility testing. Furthermore, in vivo prevention and treatment trials were conducted to assess the efficacy of the CHF-MccJ25 combination against calf diarrhea, including evaluation of clinical symptoms, fecal microbial composition, and immune parameters.Results: The results showed that out of 100 diarrheic calves fecal samples were collected from 10 cattle farms in the Ningxia Hui Autonomous Region. 97 E. coli strains and 20 Salmonella strains were detected. In vitro, the combination of Chinese Herbal Formula (CHF) and Microcin J25(MCJ) showed a synergistic inhibitory effect against E. coli and Salmonella. Moreover, the combined treatment also exhibited virulence-inhibitory activity. In vivo, the combination effectively reduced the incidence of diarrhea in healthy calves in a dose-dependence.Discussion: In summary, our study indicated that the combination of Chinese Herbal Formula (CHF) and Microcin J25(MCJ) effectively combated multidrug-resistant E. coli and Salmonella, improving both prevention and treatment of calf diarrhea by enhancing immunity and restoring gut microbiota balance.