[In vitro activity of ß-lactamase inhibitors avibanvctam and relebactam in combination with ß-lactams against multidrug-resistant Mycobacterium tuberculosis and mutations of resistance genes].

Objective: To evaluate the activity of six ß-lactams in combination with three ß-lactamase inhibitors against mycobacterium tuberculosis(MTB) in vitro. Methods: A total of 105 multidrug-resistant tuberculosis (MDR-TB) strains from different regions of Henan province from January to September 2020 were included in this study. Drug activity of six ß-lactams (biapenem, meropenem, imipenem, doripenem, ertapenem and tebipenem) alone or in combination with ß-lactamase inhibitors (clavulanic acid, avibactam and relebactam) was examined by minimum inhibitory concentration method (MICs) against 105 clinical isolates. Mutations of blaC, ldtmt1 and ldtmt2 were analyzed by PCR and DNA sequencing. Chi-square test was used to compare the antimicrobial activities of different ß-lactam drugs. Results: Out of the ß-lactams used herein, tebipenem was the most effective against MDR-TB and had an MIC50 value of 8 mg/L(χ2=123.70,P=0.001). Besides, after the addition of ß-lactamase inhibitors, the MICs of most ß-lactam drugs were reduced more evidently in the presence of avibactam and relebactam compared to clavulanic acid.Especially, relebactam decreased both the MIC50 and MIC90 of telbipenem by 16-fold, and diluted the MIC of 23 (21.90%) and 41 (39.04%) isolatesby 32-fold and 16-fold.In addition, a total of 13.33% (14/105) of isolates harbored mutations in the blaC gene, with three different nucleotide substitutions: AGT333AGG, AAC638ACC and ATC786ATT. For the strains with Ser111Arg and Asn213Thr substitution in BlaC, the MIC values of the meropenem-clavulanate combination were reduced compared with a synonymous single nucleotide polymorphism (SNP) group. Conclusions: Both avibactam and relebactam had better synergistic effects on ß-lactams than clavulanic acid. The combination of tebipenem and relebactam showed the most potent activity against MDR-TB isolates. In addition, the Ser111Arg and Asn213Thr substitution of BlaC may be associated with an increased susceptibility of MDR-TB isolates to meropenem in the presence of clavulanate.

[The effect of berberine in sterilizing infective root canal of deciduous teeth].

This investigation introduces the effect of sterilizing infective deciduous root canal with Chinese traditional herb berberine. Through the bacterial test, animal test, clinical practice, and comparing with the dental root disinfectant for mocresol (FC) and comphorphenol (CP) it indicates that berberine Chinese traditional herb is a excellent disinfectant for infective deciduous root canal.

Total knee replacement with minimally constrained prostheses in spontaneous bony ankylosis.

Total knee replacement has been carried out in the 4 knees of 2 patients for spontaneous bony ankylosis. Minimally constrained prostheses were used because the ligaments were usually intact and the patellofemoral and tibiofemoral joint lines could be re-established. The approach and repair was by a V-Y quadricepsplasty. Satisfactory results were obtained.

Primary pyogenic abscess of the psoas muscle.

During a six-year period, eleven persons with primary pyogenic abscess of the psoas muscle were treated at the Mackay Memorial Hospital. Five were males and six were females and their average age was 47.2 years (range 6-83 years). The abscess was identified by CT in 7 patients, MRI in 2 and ultrasonography in 1. One abscess was found during laparotomy. Treatment included extraperitoneal drainage of the abscess in 7 patients and CT guided aspiration in 3. One patient improved after antibiotic therapy and they all recovered after treatment. The diagnosis of primary pyogenic abscess requires a high index of suspicion and the best treatment is early operative drainage and administration of systemic antibiotics.