Antimicrobial-Resistant Escherichia coli Distribution and Whole-Genome Analysis of Sequence Type 131 Escherichia coli Isolates in Public Restrooms in Taiwan.

The threat of antibiotic-resistant bacteria to public health may originate from public restrooms. To better understand the community burden of antimicrobial-resistant Escherichia coli and sequence type complex 131 E. coli (STc131) in the public restroom, we performed a surveillance in public restrooms in southern Taiwan. Swabs were sampled from randomly selected public restrooms in Tainan, Taiwan in 2019. Antimicrobial susceptibility, phylogenetic grouping, and multiplex PCR were performed for the major ST complex in the B2 phylogenetic group. If STc131 isolates were identified, the whole-genome sequencing was performed. A total of 613 collection sites found 132 sites (21.5%) positive for E. coli. The most common phylogenetic group was A (30.9%) followed by B2 (30.3%). Ceftriaxone-resistant E. coli and extended-spectrum ß-lactamases-producing E. coli were found in 2.4 and 1.0% of total public restrooms, respectively. The isolates in rural areas had higher ceftriaxone non-susceptibility than those in the city centers (3.9 vs. 1.2%, P = 0.038). Nine STc131 isolates were found in public restrooms, and most (77.8%) belonged to the subtype fimH41, whereas 22.2% belonged to fimH30. With the inclusion of STc131 isolates from human and dog fecal colonization in Taiwan, whole-genome sequencing was performed in 35 isolates. A large cluster of fimH41 in SNP-tree and GrapeTree was found from different sources (human, dog, and environment) and geographical areas. In conclusion, our surveillance of antimicrobial-resistant E. coli showed a higher prevalence of E. coli detected in public restrooms in the rural areas compared to those in city centers. The whole-genome sequence implies that fimH41 STc131 strains are successfully circulated in the community in Taiwan.

Antibiotic-Resistant Escherichia coli and Sequence Type 131 in Fecal Colonization in Dogs in Taiwan.

BACKGROUND: Most drug-resistant Escherichia coli isolates in dogs come from diseased dogs. Prior to this study, the prevalence and risk factors of fecal carriage drug-resistant E. coli and epidemic clone sequence type (ST) 131 (including subtypes) isolates in dogs were unknown. METHODS: Rectal swabs were used for E. coli isolation from 299 non-infectious dogs in a veterinary teaching hospital in Taiwan. Antibiotic resistance and multiplex PCR analyses of E. coli for major STs were performed. RESULT: There were 43.1% cefazolin-resistant, 22.1% fluoroquinolone-resistant, and 9.4% extended-spectrum beta-lactamase-producing E. coli in our cohort. In the phylogenetic study, B2 was the predominant group (30.1%). The cefazolin-resistant group and ciprofloxacin-resistant group had greater antibiotic exposure in the last 14 days (p < 0.05). The age, sex, and dietary habits of the antibiotic-resistant and -susceptible groups were similar. In the seven isolates of ST131 in fecal colonization, the most predominant subtypes were FimH41 and FimH22. CONCLUSION: Recent antibiotic exposure was related to the fecal carriage of antibiotic-resistant E. coli isolates. Three major subtypes (FimH41, H22, and H30) of ST131 can thus be found in fecal carriage in dogs in Taiwan.

Enhancement of chitosan nanoparticle-facilitated gene transfection by ultrasound both in vitro and in vivo.

In recent years, inefficiency of transfection and the lack of safe gene vectors have limited the feasibility of gene therapy. Fabrication of a vector that is safe and has high transfection efficiency is crucial for the development of successful gene therapies. Herein, we complexed chitosan to plasmids at various N/P ratios, the molar ratios of the amino groups of chitosan to the phosphate groups of DNA, to create chitosan-DNA nanoparticles (CDNs), and then measured CDNs size, zeta-potential, efficiency of plasmid complexation, and plasmid integrity from enzyme digestion. We also used flow cytometry and fluorescence microscopy to examine the effect of an ultrasound (US) regimen on the efficiency of transfection of HeLa cells. The results revealed that the average size, zeta-potential, and loading efficiency of plasmid DNA in CDNs were 180-200 nm, 26-35 mV, and greater than 80%, respectively. Moreover, the transgene expression could be enhanced efficiently while HeLa cells or tumor tissues were given CDNs and then treated with US. Therefore, the use of chitosan nanoparticles and an US regimen shows great promise as an effective method of gene therapy.

Effect of chitosan-alginate nanoparticles and ultrasound on the efficiency of gene transfection of human cancer cells.

BACKGROUND: Gene therapy has been used to treat a variety of health problems, but transfection inefficiency and the lack of safe vectors have limited clinical progress. Fabrication of a vector that is safe and has high transfection efficiency is crucial for the development of successful gene therapy. The present study aimed to synthesize chitosan-alginate nanoparticles that can be used as carriers of the pAcGFP1-C1 plasmid and to use these nanoparticles with an ultrasound protocol to achieve high efficiency gene transfection. METHODS: Chitosan was complexed with alginate and the pAcGFP1-C1 plasmid at different charge ratios to create chitosan-alginate-DNA nanoparticles (CADNs). The average particle size and loading efficiency were measured. Plasmid DNA retardation and integrity were analysed on 1% agarose gels. The effect of CADNs and ultrasound on the efficiency of transfection of cells and subcutaneous tumors was evaluated. RESULTS: In the CADNs, the average size of incorporated plasmid DNA was 600-650 nm and the loading efficiency was greater than 90%. On the basis of the results of the plasmid DNA protection test, CADNs could protect the transgene from DNase I degradation. The transgene product expression could be enhanced efficiently if cells or tumor tissues were first given CADNs and then treated with ultrasound. CONCLUSIONS: The use of CADNs combined with an ultrasound regimen is a promising method for safe and effective gene therapy.

Exposure assessment of organic solvents for aircraft paint stripping and spraying workers.

The main objective of this study is to investigate the personal or area exposure of organic solvents during paint stripping and paint spraying. Three aircraft paint stripping/spraying workplaces in Taiwan were selected, and the Council of Labor Affairs and NIOSH recommended sampling/analytical methods used in this study. Activated charcoal tubes were used to investigate the personal and area exposure concentration of organic solvents in paint stripping and paint spraying operations. During aircraft paint stripping, experiment results show that methylene chloride personal exposure concentration at the ground area, 42.01+/-31.86 ppm, is higher than that at the working platform 4 M high above the ground, 20.41+/-11.43 ppm. Exposure concentration of methylene chloride in the initial paint stripping operation stage of every workplace is over the PEL (50 ppm) set by the Taiwan Council of Labor Affairs. Corrective actions are needed. During paint spraying, concentrations of all organic solvents were found to be below the PEL of OSHA.