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An internal complaint was initiated following a review of a 2021 scientific publication entitled, "evaluation of the performance of manual antimicrobial susceptibility testing methods and disk breakpoints for stenotrophomonas maltophilia" by khan, a.Et al.This scientific article highlighted discrepant results using etest® ceftazidime tz 256 us s30 (ref.412292).The batch numbers used for the study are unknown.The authors compared reference method, broth microdilution to other methods, including etest® , in order to evaluate the mic of 109 strains of stenotrophomonas maltophila.The samples were collected from clinical blood cultures collected from 2015 to 2019.The antibiotics tested were trimethoprim/sulfamethoxazole, levofloxacin, minocycline, ceftazidime, ciprofloxacin and tigecycline.It should be noted that there are no current approved break points approved by the fda for stenotrophomonas maltophila.Per the publication " in 2009, the fda discontinued the clearance of antimicrobial susceptibility testing (ast) devices using clsi breakpoints.As there are no fda-recognized s.Maltophilia breakpoints, fda clearance of commercial ast devices for this organism is no longer possible.Thus, laboratories in the u.S.Perform ast on s.Maltophilia isolates using commercial systems that were cleared by the fda prior to 2009 (6), or off-label for devices cleared by fda after 2009.Manual methods, such as disk diffusion or gradient diffusion are also used, although these too have not been evaluated by fda since 2008." for etest® , all antibiotics but ceftazidime gave acceptable results when compared to broth microdilution method (bmd).When using the etest® ceftazidime tz 256 us s30, the authors observed 71% of categorical agreement when compared to bmd method.For this product reference, the authors obtained four (4) very major errors (false susceptible), four (4) major errors (false resistant) and 15 minor errors (intermediate instead of resistant or susceptible).The retest gave the same results.Among these errors, three (3) very major errors, one (1) major error and 14 minor errors were within one doubling dilution of the intermediate breakpoint.Finally, three (3) major errors corresponded to mic lower than one doubling dilution of the intermediate breakpoint.As this was a retrospective study, there is no adverse event related any patient's state of health.A biomérieux internal investigation has been initiated.
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