The emergence of carbapenem- and colistin-resistant Enterobacterales mediated by transmissible plasmids poses a critical One Health threat by compromising the efficacy of last-resort antimicrobials. We characterized a commensal Escherichia coli ST156 isolate recovered from a clinically healthy companion dog in South Korea that carried bla NDM-5 and mcr-1 on distinct plasmids. Antimicrobial susceptibility testing revealed a multidrug-resistant phenotype, including resistance to carbapenems (imipenem MIC, >= 8 mu g/mL) and colistin (MIC, 8 mu g/mL). Hybrid long- and short-read genome assembly localized bla NDM-5 to an IncX3 plasmid and mcr-1 to an IncX4 plasmid. Broth-mating assays showed that each plasmid was independently transferable under the corresponding single-antimicrobial selection. Among 30 transconjugant colonies screened under each selection, both resistance determinants were detected in five colistin-selected and two meropenem-selected colonies, indicating co-detection of both resistance determinants in a minority of the screened colonies. Comparative genomic analysis showed that the IncX4-mcr-1 plasmid shared a highly conserved backbone with globally distributed IncX4 plasmids from diverse sources. These findings demonstrate asymptomatic carriage of independently transferable carbapenem- and colistin-resistance plasmids in a companion animal and support the inclusion of companion animals in integrated antimicrobial resistance surveillance.
The emergence of multidrug-resistant bacteria poses a significant threat to global public health, highlighting the urgent need for novel, effective, and safe alternative agents to combat these pathogens. This study aimed to evaluate the in vitro antibacterial activity and mechanism of action of Galla chinensis extract (GCE) against porcine-origin Staphylococcus aureus . The bioactive components of Galla chinensis were extracted by water extraction with water-bath heating. The minimum inhibitory concentration (MIC) was determined using the two-fold broth microdilution method. The in vitro antibacterial activity of the GCE extract against S. aureus was evaluated by the disk diffusion assay and by monitoring bacterial growth curves at various extract concentrations. The antibacterial mechanism was investigated by assessing key indicators of bacterial membrane and envelope integrity following exposure to the extract. The GCE exhibited potent inhibitory activity against S. aureus , with an inhibition zone diameter of 3.60 ± 0.10 cm. The MIC of GCE against S. aureus was 15.63 mg/mL. Compared with the control group, bacterial growth was markedly suppressed in the extract-treated groups in a dose-dependent manner, with the inhibitory effect strengthening as the extract concentration increased. Following treatment, the alkaline phosphatase (AKP) activity, soluble protein concentration, and extracellular nucleic acid leakage of S. aureus increased in a concentration-dependent manner. Galla chinensis exhibits potent in vitro antibacterial activity against S. aureus by inhibiting bacterial growth, and its underlying mechanism is associated with disrupting the cell wall and cell membrane integrity of S. aureus .
The emergence of carbapenem- and colistin-resistant Enterobacterales mediated by transmissible plasmids poses a critical One Health threat by compromising the efficacy of last-resort antimicrobials. We characterized a commensal Escherichia coli ST156 isolate recovered from a clinically healthy companion dog in South Korea that carried bla NDM-5 and mcr-1 on distinct plasmids. Antimicrobial susceptibility testing revealed a multidrug-resistant phenotype, including resistance to carbapenems (imipenem MIC, ≥8 μg/mL) and colistin (MIC, 8 μg/mL). Hybrid long- and short-read genome assembly localized bla NDM-5 to an IncX3 plasmid and mcr-1 to an IncX4 plasmid. Broth-mating assays showed that each plasmid was independently transferable under the corresponding single-antimicrobial selection. Among 30 transconjugant colonies screened under each selection, both resistance determinants were detected in five colistin-selected and two meropenem-selected colonies, indicating co-detection of both resistance determinants in a minority of the screened colonies. Comparative genomic analysis showed that the IncX4- mcr-1 plasmid shared a highly conserved backbone with globally distributed IncX4 plasmids from diverse sources. These findings demonstrate asymptomatic carriage of independently transferable carbapenem- and colistin-resistance plasmids in a companion animal and support the inclusion of companion animals in integrated antimicrobial resistance surveillance.
Antimicrobial resistance (AMR) was exacerbated by COVID-19 pandemic. This study describes prevalence and trends of AMR in patients with diagnosed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection admitted during 2020–2022 to the intensive care unit (ICU) in Molise region, central Italy. A retrospective study was conducted, including patients aged ≥ 18 years with at least one positive bacterial or fungal culture during ICU stay. Data were related to patient demographics, ICU outcomes, healthcare-associated infections, and antimicrobial susceptibility profiles. During the 2020–2022 period, 103 ICU admissions met the inclusion criteria, yielding 268 isolations, of which 157 underwent antimicrobial susceptibility testing. Apart from high proportion of Candida albicans , Gram-negative bacteria predominated, with Pseudomonas aeruginosa , Klebsiella pneumoniae , Escherichia coli , and Acinetobacter baumannii among the most frequent. Resistance to beta-lactams and carbapenems was consistently high, while it ranged from 53.8% to 66.7% to fluoroquinolones and remained above 50% to aminoglycosides. Tetracycline resistance showed significant year-to-year variation, increasing in 2022 compared with both 2020 and 2021. AMR rates in COVID-19 patients in ICU were persistently high throughout the pandemic, with critical resistance levels in Gram-negatives, underlining the need to reinforce infection prevention and control measures and antimicrobial stewardship programs and align prescribing practices with World Health Organization AWaRe recommendations, even during public health emergencies.
Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis ( M.TB ) infection. Although there have been significant advances in the treatment of M.TB infection, it still faces significant challenges. The gut microbiota is a highly complex ecosystem that plays an important role in regulating metabolism, immune regulation, and maintaining healthy balance in the human body. More and more studies have found that while gut microbiota regulates the immune regulation process of pulmonary TB through the “gut-lung axis,” infection with M.TB can also affect the microbial stability of gut microbiota, thereby affecting host health. This article summarized and discussed the changes of gut flora in TB patients, the possible relationship and impact between gut flora and M.TB infection, and summarized and looked forward to the potential of gut flora in the treatment of TB, in order to provide a reference for the prevention and treatment of gut microorganisms in anti- M.TB infection.
