ObjectiveTo understand the drug resistance of Mycobacterium tuberculosis complex in West China Hospital, Sichuan University, analyze its drug resistance characteristics, and provide reference for the monitoring of drug-resistant tuberculosis.MethodsFrom January 2016 to March 2018, Mycobacterium tuberculosis drug susceptibility testing kit was used to detect the drug susceptibility of Mycobacterium tuberculosis culture-positive strains in Department of Laboratory Medicine, West China Hospital, Sichuan University. The tested drugs included four of the first-line anti-tuberculosis drugs: rifampicin, isoniazid, ethambutol, and streptomycin, and ten of the second-line anti-tuberculosis drugs: capreomycin, ofloxacin, ethionamide, p-aminosalicylic acid, levofloxacin, moxifloxacin, rifabutin, amikacin, kanamycin, and chlorine phenazine.ResultsA total of 130 patients (130 strains) were enrolled, including 82 newly diagnosed patients (82 strains) and 48 re-treated patients (42 strains). The drug resistance rate of the 130 patients was 37.69%. The drug resistance rate of the newly diagnosed patients (28.05%) was significantly lower than that of the re-treated patients (54.17%), and there was a statistical difference (χ2=8.794, P=0.003). The multi-drug resistance rate of the newly diagnosed patients (6.10%) was significantly lower than that of the re-treated patients (25.00%), and the difference was statistically significant (χ2=9.517, P=0.002). The resistance rate of isoniazid, rifampicin, and streptomycin in newly diagnosed patients (23.17%, 8.54%, and 7.32%, respectively) were significantly lower than those in the re-treated patients (45.83%, 41.67%, and 29.17%, respectively), and the differences were statistically significant (P<0.05). The resistance rate of ofloxacin, moxifloxacin, rifabutin and ethionamide in the newly diagnosed patients (9.76%, 8.54%, 7.31%, and 4.88%, respectively) were significantly lower than those in the re-treated patients (39.58%, 27.08%, 25.00%, and 22.92%, respectively), and the differences were statistically significant (P<0.05).ConclusionIt is necessary to strengthen the standardized treatment of patients with newly diagnosed tuberculosis, increase the treatment and management of re-treated tuberculosis patients, and prevent the generation and spread of drug-resistant patients, especially multidrug-resistant patients.
Objective To perform rapid antimicrobial susceptibility testing (RAST) on positive blood cultures of Enterobacterales using a total laboratory automation (TLA) system following both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) standards, and to evaluate the two RAST methods. Methods Positive blood culture bottles growing Enterobacterales [54 Escherichia coli (E. coli) and 60 Klebsiella pneumoniae (K. pneumoniae) isolates] were collected at West China Hospital of Sichuan University between April and August 2022. CLSI RAST (8 and 16 h) and EUCAST RAST (4, 6, and 8 h) were performed using the TLA system, and results were compared with Vitek 2 antimicrobial susceptibility testing. Results CLSI RAST demonstrated lower categorical agreement with Vitek 2 (E. coli: 66.7% at 8 h, 81.9% at 16 h; K. pneumoniae: 72.8% at 8 h, 84.0% at 16 h) and tended to overcall resistance. EUCAST RAST showed increasing zone readability over time and high categorical agreement with Vitek 2 (E. coli: 97.1%, 96.2%, and 96.1% at 4, 6, and 8 h, respectively; K. pneumoniae: 96.1%, 97.1%, and 97.9% at 4, 6, and 8 h, respectively), as well as low error rates (major errors <3%). With the exception of ciprofloxacin, both the readability and categorical agreement for each antimicrobial agent against E. coli at 8 h were favorable (>90%). Similarly, for K. pneumoniae, the readability and categorical agreement for each antimicrobial agent at 8 h also demonstrated good performance (>90%). Conclusions According to CLSI-M52 criteria, EUCAST RAST at 4, 6, and 8 h shows equivalent performance to Vitek 2. Except for ciprofloxacin against E. coli, all antimicrobials tested at 8 h exhibit good readability and categorical agreement (>90%). CLSI RAST has lower categorical agreement and a higher tendency to interpret isolates as resistant.