For 8 h, because of the fast growth rate of Enterobacterales (Figure

For 8 h, because of the fast growth rate of Enterobacterales (Figure 1b). Recently, EUCAST has defined a methodology for disk diffusion RAST, which was originally used in the performed directly in positive blood culture bottles, with the breakpoint of CZA to E. coli and K. pneumoniae for short incubations of 4, 6, and 8 h,12 while CLSI has also defined the RAST with the breakpoint of ATM for short incubations of 8 10 h.10 Therefore, considering the above two guidelines, the incubation time setting for this study was 8 h. In the study by Khan et al, the inhibition area of Enterobacterales could also be observed after incubation at 35 for 8 h when the strip stacking and strip crossing methods were carried out.9 However, neither CLSI nor EUCAST has a standard for the interpretation of relevant results at the time point of 8 h, therefore, the results of the strip stacking and strip crossing methods cannot be determined as quickly as those of the DSE method. As a user-friendly method, disk elution is mainly used to determine the susceptibility to colistin, and the volume of MH broth as the eluent is usually 10 mL.15,16 In this study, 20 L of sterile saline was used as the eluent and assisted in the diffusion of the agent contained in the upper disk to the agar. Because the absorption capacity of a single commercial disk is 20 L,17 this micro-eluent does not have an adverse effect on the bottom disk. To further evaluate the stability and repeatability of the tests, a reproducibility study was performed for the DSE method with CBA as the reference. Except for the isolates ECO5061 and ECO8096, the results of DSE were consistent with those of CBA, and the above results were stable appeared in all three independent tests (Tables 1 and S2). As the results of strains ECO5061 and ECO8096 detected by DSE showed no interaction but those detected by CBA showed synergy, both results were defined as MIE (Tables 1 and S2). According to the -lactamase detection results in this study, the two isolates did not have any peculiar characteristics (Table S1), and further research will be conducted to determine whether there are other resistance mechanisms.Loncastuximab tesirine Taken together, the results of the DSE method were repeatable and precise, with 93.Leronlimab 8 CA, 0.0 VME, 0.0 ME, and 6.2 MIE over three days of testing (Table 2).ConclusionIn summary, we describe a simple, rapid and practical method for use in clinical microbiology laboratories to perform ATMCZA combination testing. Although the strains included in this study were limited in number, the results were encouraging and exhibited excellent reproducibility.PMID:24732841 Further evaluation in a large multicentre validation study with more CRE isolates and other organisms should be performed to further improve the clinical application potential of the DSE method.https://doi.org/10.2147/IDR.SInfection and Drug Resistance 2023:DovePressPowered by TCPDF (www.tcpdf.org)DovepressLiu et alAuthor ContributionsAll authors made a significant contribution to the work reported, whether in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.FundingThis study was supported by the Anhui Province University Natural Science Research Major Projec.