Biodegradable poly(ε-caprolactone)(PCL) microcapsules containing pseudomonas were prepared by W/O/ W emulsion system. The characteristics and release behaviors of the microcapsules were investigated as a function of manufacturing conditions. The morphology and particle distribution of the microcapsules were observed by a scanning electron microscope and a particle size analyzer. The release behaviors of the pseudomonas were determined using a cell culture method. It was found that smooth and spherical microcapsules were formed by W/O/W emulsion system and particle size was in the range of 10 to 60 µm. The release behaviors of the pseudomonas were influenced by the manufacturing conditions. It was indicated that the increase of the surfactant content and stirring rate led to an increased release rate, resulting from the high specific surface area of the smaller particle size, and the increase of the PCL content provided the sustained release behaviors by the delay effect of diffusion in the release medium.
The purpose of this study was to investigate the fluoroquinolone resistance frequency of Enterococcus spp. from normal chicken feces and to analyse mutations of the gyrA and parC gene associated with fluoroquinolone resistance. Among 52 Enterococcus faecalis and 25 E. faecium isolates, 23 (44.2%) E. faecalis and 7 (28.0%) E. faecium were resistant to ciprofloxacin (CIP) by disc diffusion method. Genetic exchange in gyrA and parC gene among 2 CIP intermediate isolates and 15 CIP resistant isolates were found in the amino acid codon of Ser-83 and Asp-87, and Ser-80 and Glu-84, respectively. These mutants contained a change from Ser to Phe, Val, Tyr, Ile, Thr or Pro at codon 83 and from Glu to Gly or Leu at codon 87 in gyrA gene, and a change from Ser to Ile or Thr at codon 80 and from Glu to Asp or Lys at codon 84 in parC gene. The isolates with mutation in gyrA regardless of a mutation in parC showed high resistance (MIC ≥32 µg/ml) to CIP, enrofloxacin, norfloxacin and ofloxacin. These results suggested that gyrA gene is the primary target for 4 fluoroquinolones resistance in Enterococcus spp.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.