TABLE 1

Features of the MCR-1-producing colistin-resistant E. coli isolates and patient characteristicsa

Strain no.Date of isolationSite of isolationGenderAge range of the patient (yrs)Origin (city)MIC of colistin (μg/ml)β-lactam resistance phenotypePFGE profileSequence typemcr-1-positive plasmid typemcr-1-positive plasmid size (ca. kb)Coresistance markers
Af23March 2014BloodM50–59Pretoria4Penicillinase (TEM-1)BST10IncI270CIP, TET, SXT
Af24March 2014PusF40–49Johannesburg4Penicillinase (TEM-1)CST1007IncI265CIP, TET, SXT
Af31October 2014UrineF60–69Johannesburg8SusceptibleAST624IncHI2150CIP, TET, SXT, CHL, FLO, KAN
Af40March 2015WoundF60–69Johannesburg4ESBL (CTX-M-55)DST57IncI2NDCIP, TET, CHL, FOS, KAN, TOB, SXT
Af45May 2015UrineF60–69Johannesburg8SusceptibleEST101IncI270TET, SXT
Af48May 2015UrineF60–69Johannesburg4AmpC (CMY-2)AST624IncX430CIP, TET, SXT, CHL
Af49May 2015UrineF30–39Pretoria4ESBL (CTX-M-55)FST226NDNDCIP, TET, SXT, CHL, FOS, KAN, TOB
  • a PFGE, pulsed-field gel electrophoresis; M, male; F, female; ND, not determined; CIP, ciprofloxacin; TET, tetracycline; SXT, trimethoprim plus sulfamethoxazole; CHL, chloramphenicol; FLO, florfenicol; KAN, kanamycin; TOB, tobramycin; FOS, fosfomycin; CHL, chloramphenicol.