Optimization of Ultrasonic-Assisted Extraction of Total Flavonoids from Abrus Cantoniensis (Abriherba) by Response Surface Methodology and Evaluation of Its Anti-Inflammatory Effect.

Abrus cantoniensis is a Chinese herbal medicine with efficacy in clearing heat and detoxification, as well as relieving liver pain. The whole plant, except the seeds, can be used and consumed. Flavonoids have been found in modern pharmacological studies to have important biological activities, such as anti-inflammatory, antibacterial and antioxidant properties. The antibacterial and antioxidant bioactivities of the total flavonoids of Abrus cantoniensis (ATF) have been widely reported in national and international journals, but there are fewer studies on their anti-inflammatory effects. The present study focused on the optimization of the ultrasonic extraction process of ATF by response surface methodology and the study of its anti-inflammatory effects in vitro and in vivo. The results showed that the factors that had a great impact on the ATF extraction were the material-to-liquid ratio, ultrasonic extraction cycles and ethanol concentration. The best extraction process used a material-to-liquid ratio of 1:47, ultrasonic extraction cycles of 4 times, an ethanol concentration of 50%, an ultrasonic extraction time of 40 min and an ultrasonic power of 125 W. Under these conditions, the actual extraction rate of total flavonoids was 3.68%, which was not significantly different from the predicted value of 3.71%. In an in vitro anti-inflammatory assay, ATF was found to be effective in alleviating LPS (lipopolysaccharide)-induced inflammation in mouse peritoneal macrophages. In an in vivo anti-inflammatory assay, ATF was found to have a significant inhibitory effect on xylene-induced ear swelling in mice and cotton ball granuloma in mice, and the inhibitory effect was close to that of the positive control drug dexamethasone. This may provide a theoretical basis for the further development of the medicinal value of Abrus cantoniensis.

Phenotypic and molecular characterization of TEM-116 extended-spectrum beta-lactamase produced by a Shigella flexneri clinical isolate from chickens.

Extended-spectrum beta-lactamases (ESBLs) produced by a clinical isolate of Shigella flexneri from chickens were detected with confirmatory phenotypic tests of the Clinical and Laboratory Standards Institute, and minimum inhibitory concentrations of several antibacterial drugs against the isolate were determined by the twofold dilution method. The genotype and subtype of the ESBL-producing S. flexneri isolate were identified by PCR amplifying of ESBL genes and DNA sequencing analysis. The results revealed that the isolate was able to produce ESBLs. They were resistant to third-generation cephalosporins such as ceftiofur and ceftriaxone and showed characteristics of multidrug resistance. The ESBL gene from the S. flexneri isolate was of the TEM type. Sequence analysis indicated that the TEM-type gene had 99.1% and 99.2% identity to TEM-1D ESBL and TEM-1 beta-lactamase, respectively, at the nucleotide level. The amino acid sequence inferred from the TEM-type gene revealed three substitutions compared with the TEM-1 and TEM-1D enzymes: Ser51Gly, Val82Ila and Ala182Val. When it was compared with TEM-116 (99.8% identity), there were only two mutations (A(151)G and T(403)C) in the TEM-type gene, resulting in the substitution of Ser to Gly at position 51 in the amino acid sequence. The TEM type was a TEM-116 derivative.

Prevalence of extended-spectrum cephalosporin-resistant Escherichia coli in a farrowing farm: ST1121 clone harboring IncHI2 plasmid contributes to the dissemination of bla CMY-2.

During a regular monitoring of antimicrobial resistance in a farrowing farm in Southern China, 117 Escherichia coli isolates were obtained from sows and piglets. Compared with the isolates from piglets, the isolates from sows exhibited higher resistance rates to the tested cephalosporins. Correspondingly, the total detection rate of the bla CMY-2/bla CTX-M genes in the sow isolates (34.2%) was also significantly higher than that of the piglet isolates (13.6%; p < 0.05). The bla CMY-2 gene had a relatively high prevalence (11.1%) in the E. coli isolates. MLST and PFGE analysis revealed the clonal spread of ST1121 E. coli in most (7/13) of the bla CMY-2-positive isolates. An indistinguishable IncHI2 plasmid harboring bla CMY-2 was also identified in each of the seven ST1121 E. coli isolates. Complete sequence analysis of this IncHI2 plasmid (pEC5207) revealed that pEC5207 may have originated through recombination of an IncHI2 plasmid with a bla CMY-2-carrying IncA/C plasmid like pCFSAN007427_01. In addition to bla CMY-2, pEC5207 also carried other resistance determinants for aminoglycosides (aacA7), sulfonamides (sul1), as well as heavy metals ions, such as Cu and Ag. The susceptibility testing showed that the pEC5207 can mediate both antibiotic and heavy metal resistance. This highlights the role of pEC5207 in co-selection of bla CMY-2-positive isolates under the selective pressure of heavy metals, cephalosporins, and other antimicrobials. In conclusion, clonal spread of an ST1121 type E. coli strain harboring an IncHI2 plasmid contributed to the dissemination of bla CMY-2 in a farrowing farm in Southern China. We also have determined the first complete sequence analysis of a bla CMY-2-carrying IncHI2 plasmid.