RESUMO
OBJECTIVES: To determine the dissemination and molecular characteristics of NDM-producing Escherichia coli strains from duck farms in south-east coastal China and their threats to human health. METHODS: A total of 232 NDM-producing E. coli were recovered from 1505 samples collected from 25 duck farms and their surrounding environments in five provinces in China. Resistance genes were confirmed using PCR. Genomic characteristics of the carbapenemase-producing isolates were determined by WGS and bioinformatic analysis. RESULTS: The rate of NDM-positive E. coli detected in samples from the five provinces ranged from 3.7% to 28.5%. There was substantial variation in the prevalence of NDM-positive E. coli from different duck farms in each province studied. Three variants (blaNDM-1, blaNDM-4 and blaNDM-5) were found in 232 NDM-positive E. coli; blaNDM-5 (94.8%, 220/232) was the most prevalent. WGS analysis indicated that ST746, ST48, ST1011 and ST167 E. coli isolates were prevalent in the current study and poultry was likely the primary reservoir for NDM-positive ST746 and ST48 E. coli in China. Phylogenomic analysis showed that NDM-positive E. coli isolates from ducks were closely related to those of human origin. In addition, WGS analysis further revealed that blaNDM co-existed with other antibiotic resistance genes, conferring resistance to nine classes of antimicrobials. CONCLUSIONS: This study revealed that ducks farm in China are an important reservoir for NDM-positive E. coli and STs of the isolates showed obvious distinctive diversities in geographical distribution. The distribution and spread of NDM-positive E. coli in duck farms poses a threat to public health.
Assuntos
Patos , Escherichia coli , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias , China/epidemiologia , Escherichia coli/genética , Fazendas , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , beta-Lactamases/genéticaRESUMO
Intestinal pathogenic Escherichia coli (InPEC) is one of the most common causes of bacterial diarrhea in farm animals, including profuse neonatal diarrhea and post weaning diarrhea (PWD) in piglets. In this study, we investigated the prevalence of InPEC and associated primary virulence factors among 543 non-duplicate E. coli isolates from diarrheal pigs from 15 swine farms in southern China. Six major virulence genes associated with InPEC were identified among 69 (12.71â¯%) E. coli isolates and included est (6.62â¯%), K88 (4.79â¯%), elt (3.68â¯%), eae (1.47â¯%), stx2 (0.92â¯%) and F18 (0.55â¯%). Three pathotypes of InPEC were identified including ETEC (8.10â¯%), EPEC (1.29â¯%) and STEC/ETEC (0.92â¯%). In particular, K88 was only found in ETEC from breeding farms, whereas F18 was only present in STEC/ETEC hybrid from finishing farms. Whole genome sequence analysis of 37 E. coli isolates revealed that InPEC strains frequently co-carried multiple antibiotic resistance gene (ARG). est, elt and F18 were also found to co-locate with ARGs on a single IncFIB/IncFII plasmid. InPEC isolates from different pathotypes also possessed different profiles of virulence genes and antimicrobial resistance genes. Population structure analysis demonstrated that InPEC isolates from different pathotypes were highly heterogeneous whereas those of the same pathotype were extremely similar. Plasmid analysis revealed that K88 and/or est/elt were found on pGX18-2-like/pGX203-2-like and pGX203-1-like IncFII plasmids, while F18 and elt/est, as well as diverse ARGs were found to co-locate on IncFII/IncFIB plasmids with a non-typical backbone. Moreover, these key virulence genes were flanked by or adjacent to IS elements. Our findings indicated that both clonal expansion and horizontal spread of epidemic IncFII plasmids contributed to the prevalence of InPEC and the specific virulence genes (F4, F18, elt and est) in the tested swine farms.
Assuntos
Diarreia , Infecções por Escherichia coli , Escherichia coli , Doenças dos Suínos , Fatores de Virulência , Animais , Suínos , Doenças dos Suínos/microbiologia , Doenças dos Suínos/epidemiologia , China/epidemiologia , Infecções por Escherichia coli/veterinária , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/epidemiologia , Diarreia/microbiologia , Diarreia/veterinária , Diarreia/epidemiologia , Prevalência , Fatores de Virulência/genética , Escherichia coli/genética , Escherichia coli/patogenicidade , Escherichia coli/isolamento & purificação , Escherichia coli/classificação , Virulência/genética , Intestinos/microbiologia , Sequenciamento Completo do Genoma , Escherichia coli Enterotoxigênica/genética , Escherichia coli Enterotoxigênica/patogenicidade , Escherichia coli Enterotoxigênica/isolamento & purificação , Proteínas de Escherichia coli/genéticaRESUMO
Targeted antibiotic delivery system would be an ideal solution for the treatment of enteropathogenic infections since it avoids the excessive usage of antibiotics clinically, which may lead to threat on public health and food safety. Salmonella spp. are Enteropathogens, but they are also robust H2S producers in the intestinal tracts of hosts. To this end, the PEGylated poly (α lipoic acid) (PEG-PALA) copolymer nanoparticles with hydrophilic exterior and hydrophobic interior were designated in this study to encapsulate the antibiotics and release them in response to H2S produced by Salmonella spp. The PEG-PALA nanoparticles demonstrated excellent stability in vitro and biocompatibility toward mammalian Caco-2 and 293 T cells. The release of ciprofloxacin from PEG-PALA nanoparticle was only 25.44 ± 0.57% and 26.98 ± 1.93% (w/w) in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) solutions without H2S stimulation. However, the release amounts of ciprofloxacin were up to 73.68 ± 1.63% (w/w) in the presence of 1 mM Na2S as H2S source. In the mouse infection model, PEG-PALA nanoparticles encapsulated with ciprofloxacin (PEG-PALA@CIP) reduced the Salmonella colonization in the heart, liver, spleen, lung, cecum, and faeces, prolonged ciprofloxacin persistence in the intestine while reducing its absorption into the blood. More importantly, these nanoparticles reduced 3.4-fold of Enterobacteriaceae levels and increased 1.5-fold of the Lactobacillaceae levels compared with the drug administered in the free form. Moreover, these nanoparticles resulted in only minimal signs of intestinal tract inflammation. The H2S-responsive antibiotic delivery systems reported in this study demonstrating a variety of advantages including protected the drug from deactivation by gastric and intestinal fluids, maintained a high concentration in the intestinal tract and maximally kept the gut microbiota homeostasis. As such, this targeted antibiotic delivery systems are for the encapsulation of antibiotics to target specific enteropathogens.
Assuntos
Nanopartículas , Ácido Tióctico , Humanos , Camundongos , Animais , Ciprofloxacina/química , Células CACO-2 , Nanopartículas/química , Salmonella , Antibacterianos/química , Polietilenoglicóis/química , Sistemas de Liberação de Medicamentos , MamíferosRESUMO
A rapid and accurate detection of carbapenemase-producing Gram-negative bacteria (CPGNB) has an immediate demand in the clinic. Here, we developed and validated a method for rapid detection of CPGNB using Blue-Carba combined with deep learning (designated as AI-Blue-Carba). The optimum bacterial suspension concentration and detection wavelength were determined using a Multimode Plate Reader and integrated with deep learning modeling. We examined 160 carbapenemase-producing and non-carbapenemase-producing bacteria using the Blue-Carba test and a series of time and optical density values were obtained to build and validate the machine models. Subsequently, a simplified model was re-evaluated by descending the dataset from 13 time points to 2 time points. The best suitable bacterial concentration was determined to be 1.5 optical density (OD) and the optimum detection wavelength for AI-Blue-Carba was set as 615 nm. Among the 2 models (LRM and LSTM), the LSTM model generated the higher ROC-AUC value. Moreover, the simplified LSTM model trained by short time points (0-15 min) did not impair the accuracy of LSTM model. Compared with the traditional Blue-Carba, the AI-Blue-Carba method has a sensitivity of 95.3% and a specificity of 95.7% at 15 min, which is a rapid and accurate method to detect CPGNB.
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Stenotrophomonas maltophilia is emerging as a significant cause of human and animal disease worldwide. A total of 3400 samples were collected from animal farms and adjacent environments in China. The blaL1 and blaL2 genes were identified using whole genome sequence analyses and examined by phylogenetics. Isolates were also tested for susceptibility to 18 antibiotics. We isolated 118 strains of S. maltophilia from 3400 samples. The positive rates of blaL1 and blaL2 genes were 75% (89/118) and 22% (26/118) and we identified 11 L1 and 6 L2 amino acid sequence variants. S. maltophilia has at least two inducible ß-lactamases (L1 and L2) that can hydrolyze almost all classes of ß-lactams and these genes are suspected to confer carbapenem resistance. This represents a significant public health threat especially for hospitalized patients. We conducted a molecular surveillance study on the prevalence and characteristics of the blaL1 and blaL2 genes of S. maltophilia.