Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar
2
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
Background: Colistin has become a last-resort antibiotic for the management of multidrug-resistant gram-negative bacteria. The disk diffusion test is cheap and easy to perform but may be unreliable for colistin susceptibility testing due to poor diffusion of the large colistin molecule. An improved agar diffusion test would increase the reliability of colistin susceptibility testing. This study aimed to modify Muller-Hinton agar (MHA) to improve colistin diffusion in agar. Methods: MHA was modified by reducing the agar concentration from 100% to 30% and supplementing with protamine. We tested 60 gram-negative clinical isolates of Pseudomonas aeruginosa (N=27) and Acinetobacter calcoaceticus-baumannii complex (N=33). Disk diffusion test results were interpreted based on minimum inhibitory concentrations determined by broth microdilution. Results: The modified MHA yielded the best performance metrics, including 94.7% sensitivity, 100% specificity, and an area under the curve of 0.995 (95% confidence interval, 0.982–1.000), P<0.001, at a cut-off point of 13 mm. Conclusions: A reduction of the agar concentration from 100% to 30% and the addition of protamine improved colistin diffusion in agar and allowed routine colistin susceptibility testing in a clinical microbiology laboratory, but should be handled with caution.
Abstract
Background: Colistin has become a last-resort antibiotic for the management of multidrug-resistant gram-negative bacteria. The disk diffusion test is cheap and easy to perform but may be unreliable for colistin susceptibility testing due to poor diffusion of the large colistin molecule. An improved agar diffusion test would increase the reliability of colistin susceptibility testing. This study aimed to modify Muller-Hinton agar (MHA) to improve colistin diffusion in agar. Methods: MHA was modified by reducing the agar concentration from 100% to 30% and supplementing with protamine. We tested 60 gram-negative clinical isolates of Pseudomonas aeruginosa (N=27) and Acinetobacter calcoaceticus-baumannii complex (N=33). Disk diffusion test results were interpreted based on minimum inhibitory concentrations determined by broth microdilution. Results: The modified MHA yielded the best performance metrics, including 94.7% sensitivity, 100% specificity, and an area under the curve of 0.995 (95% confidence interval, 0.982–1.000), P<0.001, at a cut-off point of 13 mm. Conclusions: A reduction of the agar concentration from 100% to 30% and the addition of protamine improved colistin diffusion in agar and allowed routine colistin susceptibility testing in a clinical microbiology laboratory, but should be handled with caution.
참고문헌 (24)
- Bergen PJ, "Colistin methanesulfonate is an inactive prodrug of colistin against Pseudomonas aeruginosa", Antimicrob Agents Chemother, 50, pp.1953~1958 (2006)
- Stojanoski V, "Structure of the catalytic domain of the colistin resistance enzyme MCR-1", BMC Biol, 14, pp.81~ (2016)
- Falagas ME, "Colistin: the revival of polymyxins for the management of multidrug-resistant gram-negative bacterial infections", Clin Infect Dis, 40, pp.1333~1341 (2005)
- Gupta S, "Colistin and polymyxin B : a re-emergence", Indian J Crit Care Med, 13, pp.49~53 (2009)
- Huang J, "Intravenous colistin sulfate: a rarely used form of polymyxin E for the treatment of severe multidrug-resistant Gram-negative bacterial infections", Scand J Infect Dis, 42, pp.260~265 (2010)
- Bosso JA, "Toxicity of colistin in cystic fibrosis patients", DICP, 25, pp.1168~1170 (1991)
- Poirel L, "Polymyxins: antibacterial activity, susceptibility testing, and resistance mechanisms encoded by plasmids or chromosomes", Clin Microbiol Rev, 30, pp.557~596 (2017)
- Suzuki T, "The chemical structure of polymyxin E : the identities of polymyxin E1 with colistin A and of polymyxin E2 with colistin B", J Biochem, 57, pp.226~227 (1965)
- Walkty A, "In vitro activity of colistin (polymyxin E) against 3,480 isolates of gram-negative bacilli obtained from patients in Canadian hospitals in the CANWARD Study, 2007-2008", Antimicrob Agents Chemother, 53, pp.4924~4926 (2009)
- Yu Z, "Antibacterial mechanisms of polymyxin and bacterial resistance", Biomed Res Int, 2015, pp.679109~ (2015)
- Bialvaei AZ, "Colistin, mechanisms and prevalence of resistance", Curr Med Res Opin, 31, pp.707~721 (2015)
- de Louvois J, "Factors influencing the assay of antimicrobial drugs in clinical samples by the agar plate diffusion method", J Antimicrob Chemother, 9, pp.253~265 (1982)
- Dafopoulou K, "Comparative evaluation of colistin susceptibility testing methods among carbapenem-nonsusceptible Klebsiella pneumoniae and Acinetobacter baumannii clinical isolates", Antimicrob Agents Chemother, 59, pp.4625~4630 (2015)
- Balaji V, "Polymyxins: antimicrobial susceptibility concerns and therapeutic options", Indian J Med Microbiol, 29, pp.230~242 (2011)
- Galani I, "Colistin susceptibility testing by Etest and disk diffusion methods", Int J Antimicrob Agents, 31, pp.434~439 (2008)
- Moskowitz SM, "PmrAB, a two-component regulatory system of Pseudomonas aeruginosa that modulates resistance to cationic antimicrobial peptides and addition of aminoarabinose to lipid A", J Bacteriol, 186, pp.575~579 (2004)
- Moskowitz SM, "Colistin susceptibility testing: evaluation of reliability for cystic fibrosis isolates of Pseudomonas aeruginosa and Stenotrophomonas maltophilia", J Antimicrob Chemother, 65, pp.1416~1423 (2010)
- Simar S, "Colistin and polymyxin B minimal inhibitory concentrations determined by Etest found unreliable for gram-negative bacilli", Ochsner J, 17, pp.239~242 (2017)
- Tan T, "Comparison of Etest, Vitek and agar dilution for susceptibility testing of colistin", Clin Microbiol Infect, 13, pp.541~544 (2007)
- Bakthavatchalam YD, "Challenges, issues and warnings from CLSI and EUCAST working group on Polymyxin susceptibility testing", J Clin Diagn Res, pp.DL03~DL4 (2017)
- CLSI, "Performance standards for antimicrobial susceptibility testing" (2018), Clinical and Laboratory Standards Institute
- Humphries RM, "Susceptibility testing of the polymyxins : where are we now", Pharmacotherapy, 35, pp.22~27 (2015)
- Turlej-Rogacka A, "Evaluation of colistin stability in agar and comparison of four methods for MIC testing of colistin", Eur J Clin Microbiol Infect Dis, 37, pp.345~353 (2018)
- Uyttendaele M, "Evaluation of the antimicrobial activity of protamine", Food Microbiol, 11, pp.417~427 (1994)
