Epidemiological characteristics of human- and chicken-derived CTX-M-type extended-spectrum ß-lactamase-producing Escherichia coli from China.

Bacterial resistance to ß-lactams is mainly attributed to CTX-M-type extended-spectrum ß-lactamases (ESBLs). However, the predominant sequence type (ST) of blaCTX-M-carrying Escherichia coli (blaCTX-M-Ec) in chickens, an important food animal, in China and its contribution to human ß-lactam resistance are not investigated. In this study, approximately 1808 chicken-derived strains collected from 10 provinces from 2012 to 2020 were screened for blaCTX-M-Ec, and 222 blaCTX-M-Ec were identified. Antimicrobial susceptibility tests, whole genome sequencing and conjugation experiment were performed. All quality-controlled 136 chicken-derived blaCTX-M-Ec and 1193 human-derived blaCTX-M-Ec genomes were downloaded from NCBI and EnteroBase to comprehensively analyze the prevalence of blaCTX-M-Ec in China. blaCTX-M-55 (153/358, 42.7% in chicken isolates; 312/1193, 26.2% in human isolates) and blaCTX-M-14 (92/358, 25.7% in chicken isolates; 450/1193, 37.7% in human isolates) were dominant in blaCTX-M-Ec. The STs of blaCTX-M-Ec were diverse and scattered, with ST155 (n = 21) and ST152 (n = 120) being the most abundant in chicken- and human-derived isolates, respectively. Few examples indicated that chicken- and human-derived blaCTX-M-Ec have 10 or less core genome single nucleotide polymorphisms (cgSNPs). Genetic environment analysis indicated that ISEcp1, IS26 and IS903B were closely associated with blaCTX-M transfer. The almost identical pc61-55 and pM-64-1161 indicated the possibility of plasmid-mediated transmission of blaCTX-M between humans and chickens. Although the genomes of most blaCTX-M-Ec isolated from chickens and humans were quite different, the prevalence and genetic environment of blaCTX-M variants in both hosts were convergent. CTX-M-mediated resistance is more likely to spread through horizontal gene transmission than bacterial clones.

Characterisation of novel Tn7-derivatives and Tn7-like transposon found in Proteus mirabilis of food-producing animal origin in China.

OBJECTIVES: This study aimed to clarify the characteristics of Tn7-derivatives transposons in MDR Proteus mirabilis strains isolated from anal swabs of chicken and swine in China from 2015-2020. METHODS: The Tn7 tnsA gene was screened in 207 P. mirabilis isolates by polymerase chain reaction (PCR). These strains were subjected to antimicrobial susceptibility testing. Illumina Hiseq (200 × coverage) was used for genome sequencing. Transposon maps were completed by PCR and Sanger sequencing and analysed by BLAST. RESULTS: The Tn7 tnsA gene was detected in 21 strains by PCR. Eight novel Tn7-derivatives, named Tn6667, Tn6668, Tn6669, Tn6670, Tn7095, Tn7096, Tn7097 and Tn7098, were characterised. Three types of hybrid class 2/1 integrons were found at the right end of Tn7 derivatives. A novel Tn7-like transposon Tn6666 with an active integrase gene intI2, whose transposition module shows 93% nucleotide identity to the corresponding region of Tn7, was characterised in three strains. Tn6666 is also found next to Tn7097 or Tn7098 in the chromosomes of two clonally related P. mirabilis strains. The number of resistance genes carried by the novel transposons varied from 1 to 18. A novel variant of class A extended-spectrum beta-lactamase gene, blaPER-16, with eight base substitutions compared with blaPER-12, was harboured by Tn7098. CONCLUSION: Our study characterised diverse novel Tn7-derivatives and a new Tn7-like transposon in P. mirabilis. An active integrase gene intI2 might promote the diversification of Tn7-like transposons. More attention should be paid to the prevalence and evolution of Tn7-derivatives and Tn7-like transposons and antimicrobial resistance genes they carry.

Anticancer effects of juglone in OVCAR-3 human ovarian carcinoma are facilitated through programmed cell death, endogenous ROS production, inhibition of cell migration and invasion and cell cycle arrest.

The Editors of JBUON issue an Expression of Concern to 'Anticancer effects of juglone in OVCAR-3 human ovarian carcinoma are facilitated through programmed cell death, endogenous ROS production, inhibition of cell migration and invasion and cell cycle arrest', by Jun-Yu Shi, Zhe-Ren Huang, Hong-Yan Gao, Xiao-Li Xu; JBUON 2020;25(2):779-784; PMID: 32521867. Following the publication of the above article, readers drew to our attention that part of the data was possibly unreliable. We sent emails to the authors with a request to provide the raw data to prove the originality, but received no reply. Therefore, as we continue to work through the issues raised, we advise readers to interpret the information presented in the article with due caution. We thank the readers for bringing this matter to our attention. We apologize for any inconvenience it may cause.

Anticancer effects of juglone in OVCAR-3 human ovarian carcinoma are facilitated through programmed cell death, endogenous ROS production, inhibition of cell migration and invasion and cell cycle arrest.

PURPOSE: Accumulating evidence suggests that Juglone is a potent anticancer molecule of plant origin. However, its anticancer effects have not been fully explored against human ovarian cancer cells. Therefore this study was undertaken to evaluate the anticancer effects of Juglone against the human OVCAR-3 ovarian cancer cells. METHODS: Cell viability was evaluated by WST-1 assay. Cellular apoptosis was studied using fluorescence microscopy with DAPI staining. The percentage of OVCAR-3 human ovarian cancer cells was examined by using flow cytometry in combination with annexin V-FITC/propidium iodide (PI) staining. Effects on cell cycle were studied by flow cytometer while effects on cell migration and invasion were evaluated using wound healing and transwell assay, respectively. RESULTS: Juglone inhibited the growth rate of OVCAR-3 ovarian cancer cells and showed an IC50 of 30 µM. However, Juglone showed very high IC50 (100 µM) against the normal SV40 ovarian cells. DAPI staining showed that Juglone caused nuclear fragmentation of the OVCAR-3 cells, suggestive of apoptosis. Annexin V/PI staining showed that the percentage of the apoptotic OVCAR-3 cells increased from 2.15 in control to 45.24% at 60 µM concentration of Juglone. The induction of apoptosis in the OVCAR-3 cells was also accompanied with activation caspase-3, upregulation of Bax and downregulation of Bcl-2. Juglone was also found to cause an upsurge in the ROS levels in the OVCAR-3 cells. Cell cycle analysis showed that Juglone caused accumulation of the OVCAR-3 cells in the G2/M phase of the cell cycle triggering G2/M cell cycle arrest. Wound healing assay and transwell assay showed that Juglone suppressed the migration as well as the invasion of the OVCAR-3 cells, suggestive of the antimetastatic potential of this molecule. CONCLUSIONS: Juglone may prove advantageous in ovarian cancer treatment.