Microbial drug resistance最新文献

Machine learning (ML) is poised to accelerate antibiotic discovery by rapidly identifying and generating compounds with desirable properties. Despite focused effort, algorithmic advances alone have yielded only modest improvements in real-world performance. Greater gains will likely come from improved data acquisition, data representation, and model output interpretation by domain experts. Field-wide efforts in more standardized data curation, benchmarking, and publication practices are also essential to ensure that ML methods reach their full potential to help us efficiently discover new antibiotics to address unmet clinical needs. This review focuses on the data-centric choices necessary to build ML pipelines for antibiotic discovery that are robust, reliable, efficient, and biologically grounded.

Animal-derived Klebsiella pneumoniae can serve as a crucial reservoir for transmitting drug resistance genes and virulence factors of pathogens. Therefore, investigating the molecular characteristics of K. pneumoniae isolated from animal origin in different regions is of great significance. This study determined the minimum inhibitory concentration of 65 K. pneumoniae isolated from pigs by the microbroth dilution method. The drug-resistant genes and virulent factors of these strains were amplified by PCR. The correlation analysis was performed to analyze the relationship between virulence and drug resistance factors. The results showed that the drug resistance rates of the 65 K. pneumoniae strains against 12 common antibiotics ranged from 1.54% to 89.23%. The highest resistance rates were observed against ciprofloxacin and levofloxacin, followed by ampicillin and doxycycline. The resistance rates to kanamycin and amikacin were 64.62% and 58.46%, respectively, while the resistance rate to imipenem was relatively low at 9.23%. Among these strains, the carriage rate of the bla_CTX-M gene was the highest, followed by bla_SHV and bla_TEM. Among the genes encoding quinolone resistance, gyrA had the highest carriage rate, followed by qnrB, qnrA, and oqxA. Biofilm formation was detected in 86.15% of the strains, while 63.08% exhibited a high-mucoid phenotype. The virulence genes carried by these strains included magA, fimH-1, markD, entB, rmpA, iroNB, iucA, and iutA, with carriage rates ranging from 44.62% to 100.00%. Correlation analysis revealed a positive correlation between biofilm formation and the hypermucoviscous phenotype. The prevalent porcine K. pneumoniae in this region exhibit diversity in drug resistance, virulence phenotypes, virulence factors, and drug resistance genes. Strengthening the detection of molecular characteristics of porcine-derived K. pneumoniae is of great significance for preventing the transmission of this bacterium between different hosts and regions.

Organ preservation solutions (PS) contaminated with multidrug-resistant bacteria (MDRB) risk donor-derived infections in transplantation. Eravacycline (ERV), a novel tetracycline antibiotic, shows potent activity against MDRB, but its efficacy in hypothermic PS (0°C-4°C) is unverified. In this study, six multidrug-resistant bacterial strains-including carbapenem-resistant Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, VIM-positive Pseudomonas aeruginosa, carbapenemase-negative P. aeruginosa, and methicillin-resistant Staphylococcus aureus-were exposed to eravacycline diluted in preservation solution at concentrations of 25, 50, 100, and 200 mg/L for three hours at 0-4°C. Bacterial viability was assessed by colony-forming unit counts after incubation. Results showed that eravacycline at 25 mg/L inhibited methicillin-resistant S. aureus and carbapenem-resistant A. baumannii, while 50 mg/L suppressed carbapenem-resistant K. pneumoniae, E. coli, and VIM-positive P. aeruginosa. Carbapenemase-negative P. aeruginosa required 200 mg/L for inhibition. These findings indicate that eravacycline exhibits strain-dependent antibacterial activity in hypothermic preservation solution, with 50 mg/L being effective against most tested multidrug-resistant organisms except carbapenemase-negative P. aeruginosa. Further clinical studies are warranted to evaluate its potential application in transplantation settings.

Tigecycline, a last-resort antibiotic against multidrug-resistant bacteria, has recently faced emerging resistance mediated by tet(X) genes. Livestock, particularly swine, are considered potential reservoirs for these resistance determinants. This study investigated the prevalence and molecular characteristics of tigecycline-resistant Escherichia coli in healthy weaning pigs in Thailand. Fecal samples were collected from healthy weaning pigs in 2024. Detection of tet(X) genes was performed using PCR. Among the 305 fecal samples, four were positive for the tet(X4) gene. A total of four tet(X)-positive E. coli isolates exhibited low-level resistance to tigecycline (minimum inhibitory concentration: 0.5-4 mg/L). Whole-genome sequencing analysis identified the tet(X4)-positive isolates as belonging to sequence types (STs) rST-153719, rST-59143, rST-45855, and rST-86073. Multiple antimicrobial resistance genes coexisting with tet(X4) were detected, including aph(6)-Id, aph(3'')-Ib, bla_TEM-1B, bla_TEM-215, sul2, floR, tet(A), and qnrS1. Plasmids carrying tet(X4) in the E. coli isolates were identified as IncN (in strains NO25 and T8) and IncR (in strains C2 and OS57). This study reports the first detection of tigecycline-resistant E. coli from weaning pigs in Thailand, raising significant concerns for both food animal production and public health.

Unregulated use of antibiotics has led to selection pressure in many pathogens, leading to the development of antimicrobial resistance (AMR), one of the leading causes of death worldwide. The effect of AMR in humans as well as all the species of animals has been observed. Escherichia coli (E. coli), a gram-negative bacterium, colonizes in the gastrointestinal tract and maintains a mutually beneficial relationship with the host. Most of the E. coli strains are harmless and inhabit the intestinal tract, but there are certain pathogenic strains, which cause infections both in humans and animals, leading to higher chances of transmission of AMR genes. Development of AMR in E. coli strains of poultry has become a major public health concern, as poultry meat and eggs act as a direct source of transmission of these multi-resistant strains to humans. This review focuses on the worldwide emergence of AMR in E. coli strains of poultry, their impact on public health, and the importance of "One health approach" to tackle the current situation.

Introduction: Hospital-acquired respiratory infections caused by antimicrobial-resistant bacteria have become a major public health problem worldwide. This study aimed to evaluate the distribution and antimicrobial resistance profiles of bacterial strains isolated from adult patients treated with a diagnosis of lower respiratory tract infection in our hospital.

Materials and methods: Respiratory tract samples of adult patients hospitalized in our hospital were included. The identification of the isolated strains and their antibiotic susceptibilities were studied by the PHOENIX 100 (Becton Dickinson, USA) automated system, and results were evaluated according to the European Committee on Antimicrobial Susceptibility Testing criteria.

Discussion and conclusions: In this study, we observed that Gram-negative bacteria were more common than Gram-positive bacteria in lower respiratory tract samples. The multidrug resistance rate in Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii isolates is detected as 59%, 12.9%, and 96.4%, respectively. Carbapenem resistance rates for K. pneumoniae (n = 261), A. baumannii (n = 250), and P. aeruginosa (n = 132) were 88.9%, 97.2%, and 43.2%, respectively. The multidrug resistance and carbapenem resistance rates detected in lower respiratory tract samples in our study are alarming. It is noteworthy that the resistance rates we found are higher than the rates reported in other studies conducted in our country.

This study presents a case of Ralstonia mannitolilytica isolated from a blood culture of a 50-year-old male patient with hepatocellular carcinoma. The patient underwent ultrasound-guided radiofrequency ablation for liver lesions associated with hepatocellular carcinoma and subsequently experienced recurrent fever, chills, and rigors. R. mannitolilytica was identified from blood culture. This bacterium, known to be an opportunistic pathogen, has not been extensively studied for its whole-genome characteristics and resistance profiles. Through whole-genome sequencing and bioinformatics analysis, we identified 32 distinct drug resistance genes associated with various antibiotic classes, including beta-lactams, aminoglycosides, and fluoroquinolones. Our findings reveal the potential for multidrug resistance in R. mannitolilytica, which exhibited numerous resistance genes. This underscores the clinical challenge of treating infections caused by this bacterium and highlights the importance of whole-genome analysis in understanding emerging pathogens. The identification of these resistance genes is crucial for devising effective clinical strategies to combat infections, particularly in immunocompromised patients, in whom the bacterium may pose a significant risk.

Aims: Staphylococcus pseudintermedius is an opportunistic pathogen also indicated as one of the major causes of skin infections in dogs. This study aimed to identify S. pseudintermedius isolated from canine skin lesions, evaluate their antibiotic resistance profile and biofilm production ability.

Methodology: Lesions from 50 rural dogs with different skin lesions were sampled after pyoderma diagnosis by private practices. Bacterial species determination was investigated and susceptibility to nine antimicrobials were determined by means of Kirby-Bauer assay. Then seven antibiotic resistance genes, including mecA, blaZ, tetK, tetM, bla_SHV, bla_OXA-1, and bla_TEM were screened by PCR. Moreover, biofilm formation ability of the strains was determined using the microtiter plate assay along with the presence of icaADBC genes.

Results: A total of 37 (74%) isolates were identified as S. pseudintermedius. All S. pseudintermedius isolates were resistant to multiple drugs. Resistance to penicillin, amoxicillin-clavulanic acid, and cefazolin were higher than other antimicrobials. All the beta-lactam-resistant isolates carried blaZ, whereas mecA was found in 6 (16.21%) of them. Among tetracycline-resistant strains, the frequency of tetK and tetM determinants were 19 (90.47%) and 21 (100%), respectively. Finally, most cefazolin-resistant strains 31 (91.89%) were positive for blaTEM gene. The rate of biofilm production ability among S. pseudintermedius isolates was 35 (94.59%). Furthermore, the presence of icaA/D genes was detected in 35 (100%) and 29 (82.85%) of S. pseudintermedius strains, respectively.

Conclusion: The high rates of antimicrobial resistance and biofilm production ability among S. pseudintermedius isolates, emphasize the urgent need to use more effective infection control policies and guidelines for antimicrobial use.

Wild animals may act as reservoirs for resistant bacteria, and resident bacteria carried by wild animals in cities may also be subject to anthropogenic pressures that affect their resistance. This study aimed to evaluate the antibiotic susceptibility and biofilm formation ability of Escherichia coli and Klebsiella pneumoniae isolated from wild raccoon dogs from Shanghai, China, and to identify the genes responsible for resistance to different classes of antibiotics. The horizontal transfer of resistant plasmids was assessed by plasmid conjugation assays and characterized by third-generation nanopore sequencing. E. coli and K. pneumoniae isolated from wild raccoon dogs in Shanghai had strong biofilm formation ability. They had high resistance rates to amoxicillin, co-trimoxazole, tetracycline, and other antibiotics, but they were still sensitive to advanced antibiotics. The isolates contained prevalent resistance genes and virulence genes, and plasmids could be transferred horizontally. The resistant plasmids are rich in gene transfer elements such as insertion sequences. This is the first description of the antimicrobial resistance status and genes of wild raccoon dogs in Shanghai. These results highlight the urgent need to understand the origin and spread of resistance genes in wild animals such as urban raccoon dogs in Shanghai.

Campylobacter contamination in chicken meat, particularly with fluoroquinolone- and macrolide-resistant strains, is a significant public health concern. Therefore, developing an easy and rapid detection method for fluoroquinolone- and macrolide-resistant Campylobacter will improve food safety. In this study, we designed and evaluated a multiplex-Polymerase Chain Reaction (PCR) method for the simultaneous detection of fluoroquinolone- and macrolide-resistant Campylobacter jejuni and Campylobacter coli in chicken meat. Our multiplex-PCR-targeted mutations in the gyrA and rrl genes of Campylobacter species confer resistance to fluoroquinolones and macrolides, respectively. Overall, this method could detect Campylobacter contamination and identify C. jejuni and C. coli as well as their susceptibility to fluoroquinolone and macrolide. Spiking of chicken meat samples revealed that multiplex-PCR can detect at least 0.72 Colony-Forming Unit (CFU)/g C. jejuni/coli. Among 277 retail chicken meat samples, C. jejuni/coli were detected in 54 samples using multiplex-PCR, with isolation from 52 samples using microbial culture. The susceptibility of the isolates to fluoroquinolones and macrolides was determined using both the PCR and culture methods, and a comparison of these methods showed that the accuracy, specificity, and sensitivity were all above 95%. The culture method required approximately 8 days for Campylobacter isolation and antimicrobial susceptibility testing. Multiplex-PCR could determine the contamination with C. jejuni/coli and susceptibility to fluoroquinolones and macrolides within 2-3 days from the enrichment culture to final determination. These results indicate that the proposed multiplex-PCR enables rapid and simultaneous detection of fluoroquinolone- and macrolide-resistant C. jejuni/coli in chicken meat and its utility for monitoring their contamination in food.