Objective:To analyse the drug resistance of Stenotrophomonas maltophilia(Sm) for rational application of antibiotics in clinics. Methods:Antimicrobial susceptibility tests were processed by K-B method, metallo-?-lactamases (MBLs) were screened by synergic method, and extended-spectrum ?-lactamases (ESBL) were detected by double disk synergy test. Results:42 Sm strains were completely resistant to imipenem, highly resistant to cefotaxime (CTX), amikacin (AMK), aztreonam (ATM) and piperacillin-tazobactam (TZP) (the resistance rates were 92%,83%,78% and 64%, respectively). They showed low resistance rates to sulfamethoxazole/trimethoprim(SMZ/TMP), cefoperazone/sulbactam(CFS), ciprofloxacin (CIP) and ticarcillin/clavulanate (TIM)(26%,16%,12% and 9%, respectively). There were 71.43% strains of Sm producing ESBL, 80.95% producing MBL, and 57.14% producing both ESBL and MBL. Conclusion:There are many kinds of mechanism contributing to the drug resistance of Sm, to which more attention should be paid by clinicians.

Objective:To investigate whether there is another resistance mechanism besides mecA gene in oxacillin-resistant(OR) isolates of Staphylococcus aureus(S.aureus). Methods:There were 130 oxacillin-resistant phenotype isolates of S. aureus. Of these isolates 125 were resistant to more than 3 of 5 non-?-lactams (gentamicin, ciprofloxacin, clindamycin, tetracycline, erythromycin) (OR-R) and 5 susceptible to more than 3 of the 5 non-?-lactams (OR-S) and 14 were oxacillin-susceptible (OS) phenotype isolates of S. aureus and resistant to more than 3 of 5 non-?-lactams (OS-R). All the strains were detected by the two disks diffusion tests with oxacillin (OXA) and oxacillin/clavulanic acid (OXA/CA), by the three-dimensional extract tests of penicillin (PEN) and OXA for penicillinase and oxacillinase, and by PCR tests for mecA. Results:The 130 OR and 14 OS isolates were all oxacillinase-negative with the two disks diffusion tests, all pencillinase-positive and oxacillinase-negative in the three-dimensional extract tests. The mecA gene was detected in 125 OR-R-type and 2 of the 5 OR-S-type isolates, but was not detected in the other 3 OR-S-type nor in any of the 14 OS-R-type isolates by PCR. Conclusion:In a few Staphylococcus aureus strains which are phenotype of oxacillin-resistant and are susceptible to mostly non-?-lactam agents there are both mecA-negative and oxacillinase-negative strains, 2.3% (3/130) of the OXA-resistant strains. The resistance mechanism may be associated with reduced binding capacity of the modified Preexisting PBPs with OXA.

Objective:Exploring the effect of radiofrequency ablation treatment to restore sinus rhythm on the improvement of functional mitral regurgitation (FMR) and cardiac structure in patients with atrial fibrillation combined with moderate or severe FMR, compared with drug therapy alone.Methods:This retrospective cohort study consecutively enrolled patients diagnosed with persistent atrial fibrillation and moderate or severe FMR who were admitted to the Third Affiliated Hospital of Sun Yat-sen University from January 2019 to December 2021. Forty-eight patients who were treated with radiofrequency ablation and maintained sinus rhythm were enrolled in the ablation group, and 63 patients who were treated with medication alone during the same period were in the medicine group. Patients in the ablation group and medicine group were matched in a 1∶1 ratio using a propensity score, and 41 patients were finally included in each of the 2 groups. All patients reexamined echocardiography after 3-month of treatment. The proportion of patients with FMR improvement and the differences in changes of cardiac structural and functional parameters were compared between groups.Results:After propensity score matching, the ablation group was aged (69.3±7.1) years with 21 males (51.2%) and the medicine group was aged (71.3±9.4) years with 21 males (51.2%). The echocardiography after 3-month of treatment showed the rate of FMR improvement was significantly higher in the ablation group than in the medicine group (19 (46.3%) vs. 33 (80.5%), P<0.001), and patients in the ablation group showed a significant decrease in FMR extent (Δmitral regurgitation area: (-1.30±2.64) cm 2 vs. (-3.55±2.50) cm 2, P<0.001), left atrial size (Δleft atrial diameter: (-0.17±3.78) mm vs. (-2.46±4.01) mm, P=0.009) and E/e′ (ΔE/e′:-2.54±7.34 vs.-6.34±7.08, P=0.021) compared with the medicine group. There was also a significant decrease in left ventricular size (Δleft ventricular end diastolic diameter: (-3.12±6.62) mm vs. (-0.73±3.62) mm, P=0.046) and significant increase in left ventricular ejection fraction (Δleft ventricular ejection fraction: (2.73±9.69) % vs. (-0.93±5.41) %, P=0.038) in ablation group. Conclusion:Performing radiofrequency ablation to restore sinus rhythm can effectively reduce the severity of mitral regurgitation and improve left atrial and left ventricular remodeling and cardiac function in patients with atrial fibrillation and FMR.

The important function of the endplate is to transmit stress and supply nutrition. Endplate degeneration might induce or promote degeneration of the intervertebral disc, causing a series of spine diseases that seriously impair people’s health and life quality. Endplate chondrocytes can respond to mechanical stimulation, which is an important factor affecting endplate degeneration. Inappropriate mechanical stimulation will accelerate endplate degeneration. This review summarized the effects of mechanical stimulation on vertebral endplate chondrocyte apoptosis, synthesis inhibition, calcification, and extracellular matrix degradation. The endplate degeneration induced by mechanical stimulation is regulated by a complex network of signal pathways composed of various signal transduction factors. The signal pathways involved in this review included NF-κB, Wnt, Hedgehog, MAPK, RhoA/Rock-1, AKT/mTOR, TGF-β signaling pathway and miRNA related signals. The interconnection of these pathways was highlighted and summarized. Multiple signaling pathways work together to regulate endplate chondrocyte metabolism, which ultimately leads to the endplate degeneration. This review might shed light on early diagnosis and precise treatment of cartilage endplate degeneration.