P1632 Comparison of BD Phoenix Automated System and Etest to broth microdilution method for antimicrobial susceptibility testing of multiple resistant Pseudomonas aeruginosa and Acinetobacter spp.

ABSTRACT In recent years, the absence of acquired antimicrobial resistance has become an important criterion to evaluate the biosafety of lactobacilli used as industrial starter or probiotic cultures. At present, however, standards for susceptibility testing of Lactobacillus strains or approved guidelines for interpreting the test results are not available. Hence, this study was carried out to contribute to the establishment of a standardized procedure for antimicrobial susceptibility testing of lactobacilli. The results obtained by testing 104 strains of the Lactobacillus acidophilus group were compared based on broth microdilution, disk diffusion, and Etest. Except for some specific agent-related effects, agreement between MICs resulting from the broth microdilution method and the Etest was good. In addition, inhibition zone diameters determined with disk diffusion correlated well with MICs from Etest and broth microdilution.

Download Full-text

Polymyxin B resistance rates in carbapenem‑resistant Pseudomonas aeruginosa isolates and a comparison between Etest® and broth microdilution methods of antimicrobial susceptibility testing

Experimental and Therapeutic Medicine ◽

10.3892/etm.2020.8777 ◽

2020 ◽

Vol 20 (2) ◽

pp. 762-769

Author(s):

Xu Chen ◽

Jie Xu ◽

Qiongfang Zhu ◽

Yalu Ren ◽

Lina Zhao

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Susceptibility ◽

Susceptibility Testing ◽

Polymyxin B ◽

Antimicrobial Susceptibility Testing ◽

Broth Microdilution ◽

Carbapenem Resistant ◽

Resistance Rates

Download Full-text

Multicenter Evaluation of Colistin Broth Disk Elution and Colistin Agar Test: a Report from the Clinical and Laboratory Standards Institute

Journal of Clinical Microbiology ◽

10.1128/jcm.01269-19 ◽

2019 ◽

Vol 57 (11) ◽

Cited By ~ 11

Author(s):

Romney M. Humphries ◽

Daniel A. Green ◽

Audrey N. Schuetz ◽

Yehudit Bergman ◽

Shawna Lewis ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Susceptibility ◽

Susceptibility Testing ◽

Polymyxin B ◽

Antimicrobial Susceptibility Testing ◽

Broth Microdilution ◽

Content Type ◽

Clinical Laboratories

ABSTRACT Susceptibility testing of the polymyxins (colistin and polymyxin B) is challenging for clinical laboratories. The Clinical and Laboratory Standards Institute (CLSI) Antimicrobial Susceptibility Testing Subcommittee evaluated two methods to enable accurate testing of these agents. These methods were a colistin broth disk elution (CBDE) and a colistin agar test (CAT), the latter of which was evaluated using two inoculum volumes, 1 μl (CAT-1) and 10 μl (CAT-10). The methods were evaluated using a collection of 270 isolates of Enterobacterales, 122 Pseudomonas aeruginosa isolates, and 106 Acinetobacter spp. isolates. Overall, 94.4% of CBDE results were in essential agreement and 97.9% in categorical agreement (CA) with reference broth microdilution MICs. Nine very major errors (VME; 3.2%) and 3 major errors (ME; 0.9%) were observed. With the CBDE, 98.6% CA was observed for Enterobacterales (2.5% VME, 0% ME), 99.3% CA was observed for P. aeruginosa (0% VME, 0.7% ME), and 93.1% CA was observed for Acinetobacter spp. (5.6% VME, 3.3% ME). Overall, CA was 94.9% with 6.8% VME using CAT-1 and improved to 98.3% with 3.9% VME using CAT-10. No ME were observed using either CAT-1 or CAT-10. Using the CAT-1/CAT-10, the CA observed was 99.4%/99.7% for Enterobacterales (1%/0.5% VME), 98.7%/100% for P. aeruginosa (8.3%/0% VME), and 88.5%/92.3% for Acinetobacter spp. (21.4%/14.3% VME). Based on these data, the CLSI antimicrobial susceptibility testing (AST) subcommittee endorsed the CBDE and CAT-10 methods for colistin testing of Enterobacterales and P. aeruginosa.

Download Full-text