High prevalence of blaCTX-M and blaSHV among ESBL producing E. coli isolates from beef cattle in China's Sichuan-Chongqing Circle.

Enterobacteria that produce extended-spectrum ß-lactamase (ESBL) such as Escherichia coli (E. coli) are common in our environment and known to cause serious health implications in humans and animals. ß-lactam antibiotics such as penicillins, cephalosporins and monobactams are the most commonly used anti-bacterials in both humans and animals, however, Gram negative bacteria (such as E. coli) that produces extended-spectrum ß-lactamases (ESBLs) have the ability to hydrolyze most ß-lactams therefore making them resistant to ß-lactam antibiotics. Recent extensive researches on the epidemiology and genetic characteristics of extended-spectrum ß-lactamase (ESBL)-producing E. coli reported the existence of ESBL-producing E. coli in humans, companion animals and poultry. Therefore, this experiment was performed to investigate the prevalence and genetic characteristics of ß-lactamase producing E. coli isolated from beef cattle farms in the Sichuan-Chongqing circle of China. Phenotypic confirmation of ESBL-producing E. coli was performed using the double disk synergy test. Polymerase Chain Reaction (PCR) was used to detect blaCTX-M, blaSHV and blaTEM gene codes, then after, isolates were divided into different phylogenetic groups and multi-locus sequence typing (MLST). The results showed that out of the 222 E. coli strains isolated from the beef cattle, 102 strains showed ESBL phenotypes. The PCR results showed that blaCTX-M was the predominant ESBL gene identified among the E. coli strains with 21 (9.5%) isolates having this gene, followed by blaSHV which was found in 18 (8.1%) isolates. The majority of these ESBL positive isolates were assigned to phylogroup A (19.8%) followed by phylogroup B1 (13.5%). In addition, from the MLST results on ESBL positive isolates (n = 30) we identified 19 STs, ST398 (ST398cplx) and ST7130 which were the prevalent population (20%). In conclusion, the high prevalence of CTX-M, and SHV in the study confirmed its association with E. coli infection; therefore, this calls for health concerns on ESBL-producing E. coli. As far as we know, this is the first comprehensive research report relating to ESBL-producing E. coli incidence in Chinese beef cattle.

Anticancer effect and mechanism of a Se-modified porphyrin Au(III) complex.

Au, Se and porphyrin are widely used components in the design of anticancer drugs, but their combination has never been referred to. In this work, a Se-modified porphyrin Au(III) complex, [AuTPP-Se]Cl, was designed and synthesized as a potential anticancer agent. This compound exhibits remarkable antiproliferative activity on all the six tested cancer cells. Its potency on HepG2 is even ten times higher than that of CDDP. The synergistic action among Au, Se and porphyrin components was validated. Mechanism study showed that both the induction of mitochondria-dependent apoptosis and the arrest of cell cycle contribute to the anticancer activity of [AuTPP-Se]Cl.

[Design and implementation of an intellectualized measuring instrument for medical electricity security parameters].

An introduction of an intelligent testing instrument for medical electrical equipment security is given in this article. The realization of its testing functions is based on a single-chip processor, the high-voltage control circuit and the relay combination network technology. It can be used to test security parameters such as the continuous leakage current, patient auxiliary current, dielectric strength and protective earth impedance. It is suitable for the medical electricity security testing of Kind I, II and Type B, BF, CF (internal power supply) medical electrical equipments.