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Accurate sentinel lymph node (SLN) characterization is essential for breast cancer management, prompting advancements in imaging technologies such as contrast-enhanced ultrasound (CEUS) and sound touch quantification (STQ) to enhance diagnostic precision. To explore the value of perfusion characteristics evaluated by CEUS combined with STQ parameters in diagnosing the properties of sentinel lymph node (SLN) in breast cancer. A total of 91 breast cancer patients (91 SLNs) admitted to the hospital from February 2022 to December 2023 were selected for this study. Among them, 26 patients with metastatic SLN confirmed by surgery and pathology were included in the metastatic SLN group, and 65 patients with non-metastatic SLN were included in the non-metastatic SLN group. Preoperative examination results of CEUS and STQ were retrospectively analyzed. The diagnostic efficacy of perfusion characteristics evaluated by CEUS and STQ parameters for the properties of SLN in breast cancer was analyzed using the receiver operating characteristics (ROC) curve. Statistical methods such as chi-square tests and logistic regression analysis were employed to analyze the data. Enhancement patterns differed significantly between the metastatic SLN and non-metastatic SLN groups (p< 0.05). ROC curve analysis indicated that CEUS perfusion characteristics had an AUC value of 0.823 for diagnosing SLN properties, with a sensitivity of 84.62% and specificity of 70.77% using type I as the critical value. Additionally, STQ measurement showed significantly higher values in the metastatic SLN group (44.18 ± 6.53 kPa) compared to the non-metastatic SLN group (34.69 ± 6.81 kPa) (t= 6.075, p< 0.001). The AUC value for STQ parameters in diagnosing metastatic SLN was 0.849, with a sensitivity of 73.08% and specificity of 92.31% using 42.40 kPa as the critical value. Though the AUC value of STQ measurement was higher than CEUS perfusion characteristics alone, the difference was not statistically significant (Z= 0.393, p= 0.695). Moreover, combining CEUS perfusion characteristics with STQ parameters yielded an AUC value of 0.815 for diagnosing SLN properties, showing no significant difference compared to diagnosis with CEUS or STQ parameters alone (Z= 0.149, 0.516, p= 0.882, 0.606). Combined use of perfusion characteristics evaluated by CEUS and STQ parameters can significantly improve the diagnostic specificity of SLN in breast cancer. It is worthy of clinical promotion. [ABSTRACT FROM AUTHOR]

Background Bacterial membrane vesicles (BMVs) are novel vehicles of antibiotic resistance gene (ARG) transfer in Gram-negative bacteria, but their role in the spread of ARGs in Gram-positive bacteria has not been defined. The purpose of this study was to evaluate the role of MVs in the transmission of antimicrobial resistance in Gram-positive bacteria. Methods A linezolid-resistant Enterococcus faecalis CQ20 of swine origin was selected as the donor strain. Linezolid-susceptible E. faecalis SC032 of human origin, Enterococcus faecium BM4105 and Escherichia coli were selected as recipient strains. The presence of plasmids (pCQ20-1 and pCQ20-2) and an optrA -carrying transposon Tn 6674 in CQ20, MVs and vesiculants was verified by WGS or PCR. MVs were isolated with density gradient centrifugation, and MV-mediated transformation was performed to assess the horizontal transferability of MVs. The MICs for CQ20 and its vesiculants were determined by the broth microdilution method. Results CQ20-derived MVs (CQ20-MV) were isolated, and PCR identified the presence of two plasmids and the optrA gene in the CQ20-MVs. MV-mediated transformation to E. faecalis SC032 and E. faecium BM4105 was successfully performed, and the WGS data also showed that both plasmids pCQ20-1 and pCQ20-2 and optrA -carrying transposon Tn 6674 were transferred to E. faecalis SC032 and E. faecium BM4105, but failed for E. coli. Additionally, vesiculants that had acquired ARGs still had the ability to spread these genes via MVs. Conclusions To our knowledge, this is the first report of MV-mediated co-transfer of ARG-carrying plasmids and transposons in the Gram-positive bacterium E. faecium. [ABSTRACT FROM AUTHOR]

The CTX-M-55 type extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae is increasing in prevalence worldwide without the transmission mechanism being fully clarified, which threatens public and livestock health. Outer membrane vesicles (OMVs) have been shown to mediate the gene horizontal transmission in some species. However, whether blaCTX-M-55 can be transmitted horizontally through OMVs in avian pathogenic Escherichia coli (APEC) has not been reported yet. To test this hypothesis, an ESBL-producing APEC was isolated and whole-genome sequencing (WGS) was performed to analyze the location of blaCTX-M-55. Ultracentrifugation and size exclusion chromatography was used to isolate and purify OMVs, and the transfer experiment of blaCTX-M-55 via OMVs was performed finally. Our results showed that the blaCTX-M-55 was located on an IncI2 plasmid. The number and diameter of OMVs secreted by ESBL-producing APEC treated with different antibiotics were significantly varied. The transfer experiment showed that the OMVs could mediate the horizontal transfer of blaCTX-M-55, and the frequency of gene transfer ranged from 10−5 to 10−6 CFU/mL with the highest frequency observed in the Enrofloxacin treatment group. These findings contribute to a better understanding of the antibiotics in promoting and disseminating resistance in the poultry industry and support the restrictions on the use of antibiotics in the poultry industry. [ABSTRACT FROM AUTHOR]

Objectives: To identify and characterize a novel cfr variant that recently emerged and confers multidrug resistance in Campylobacter , a major foodborne pathogen.Methods: WGS was initially used to identify the cfr (C) gene in Campylobacter isolates and its function was further verified by cloning into an antibiotic-susceptible Campylobacter jejuni strain. Distribution of cfr (C) in various Campylobacter isolates was determined by PCR analysis. Genotyping of cfr (C)-positive strains was done by PFGE and MLST.Results: The cfr (C) gene is predicted to encode a protein that shares 55.1% and 54.9% identity with Cfr and Cfr(B), respectively. cfr (C) was located on a conjugative plasmid of ∼48 kb. Cloning of cfr (C) into C. jejuni NCTC 11168 and conjugative transfer of the cfr (C)-containing plasmid confirmed its role in conferring resistance to phenicols, lincosamides, pleuromutilins and oxazolidinones, and resulted in an 8-256-fold increase in their MICs in both C. jejuni and Campylobacter coli . The cfr (C) gene was detected in multiple C. coli (34 of 344; 10%) isolates derived from different cattle farms in different states, and molecular typing of the cfr (C)-positive C. coli isolates revealed its spread mainly via clonal expansion.Conclusions: These results identify cfr (C) as a new multidrug resistance mechanism in Campylobacter and suggest the potential transmission of this mechanism via the foodborne route, warranting enhanced efforts to monitor its spread in Campylobacter and other foodborne pathogens. [ABSTRACT FROM AUTHOR]