Review Article

Development of New Tools to Detect Colistin-Resistance among Enterobacteriaceae Strains

Table 5

Comparison of detection methods for polymyxin resistance.

MethodPrincipleTimeManual (M); automated (A)Detection
ColRmcrHRMIC

Phenotypic
 Selective agarSelective growth18 hM++
 Rapid polymyxin NPpH change4 hM+
 MicromaxCell wall lysis detection by fluorescence3 hM/A+
 MALDI-TOF MSSpecific peak detection1 hA++
MCR-1 inhibitionChelation with18 hM++±+
  Colistin MACDipicolinic acid
  EDTA assaysEDTA

AST
 BMD (UMIC, Micronaut-MIC, Sensitest, Micronaut-S, and Sensititre)Growth inhibition18 hM/A+±+
 Agar diffusionMeasure of growth inhibition zone18 hM
  Disk diffusion+
  Gradient strip++
  ColiSpot+ND
 Agar dilutionGrowth inhibition18 hM++
 Automatized systemGrowth detection
  MicroScanFluorimetry3.5–7 hA+
  Vitek 2Algorithm4–10 hA+
  PhoenixOxidoreduction6–16 hA+

Genotypic
 Standard PCRAmplification3 hA++
 RT-PCRAmplification1 hA++
 LAMP (Eazyplex, etc.)Amplification20 minA+
 MicroarrayDNA hybridization6.5 hA+
 NGSWhole-genome sequencing
  Illumina4–56 hA++
  PacBio RS II0.5–3 hA++

ColR: colistin resistance; HR: heteroresistance; +: yes; −: no; ±: sometimes.