TABLE 3.
PmrAB polymorphisms of colistin-resistant E. coli isolates tested negative for mcr-1 to mcr-9.
| Isolate | Species | Origin | Colistin MIC, mg/L | Resistance phenotype (epidemiological cut-off values of EUCAST)a | Resistance phenotype (clinical breakpoints of EUCAST)b | PmrABc |
| Poultry slaughterhouses | ||||||
| C-01/07-07 | E. coli | Stunning facilities | 8 | AMP, CIP, CST, NAL, SMX, TET | PIP, CST | 2H→R (PmrB) 360A→V (PmrB) |
| C-01/07-08 | E. coli | Stunning facilities | 8 | AMP, CIP, CST, NAL, SMX, TET | PIP, CST | 2H→R (PmrB) 360A→V (PmrB) |
| C-01/07-11 | E. coli | Stunning facilities | 8 | AMP, CIP, CST, NAL, SMX, TET | PIP, CST | 2H→R (PmrB) 360A→V (PmrB) |
| C-01/07-12 | E. coli | Stunning facilities | 8 | AMP, CIP, CST, NAL, SMX, TET | PIP, CST | 2H→R (PmrB) 360A→V (PmrB) |
| 04/02-15 | E. coli | Transport crates | 8 | AMP, CHL, CIP, CST, CTX, NAL, SMX, CAZ, TET, TGC, FEP, FOX | PIP, CTX, CAZ, CIP, LVX, CHL, CST | − |
| 04/02-16 | E. coli | Transport crates | 4 | AMP, CST, CTX, SMX, CAZ, TET, TMP, FEP, FOX | PIP, CTX, CAZ, CIP, LVX, CHL, SXT, CST | − |
| 04/07-11 | E. coli | Stunning facilities | 8 | AMP, CHL, CIP, CST, CTX, NAL, SMX, CAZ, TET, FEP, FOX | PIP, CTX, CAZ, C/T, CIP, LVX, CHL, CST | − |
| C-04/03-08 | E. coli | Scalding water | 8 | AMP, CST, SMX | PIP, CIP, LVX, SXT, CST | 14L→P (PmrB) 44F→x (PmrB) |
| C-04/05-08 | E. coli | Influent in-house WWTP | 8 | AMP, CST, SMX, TMP | PIP, SXT, CST | 14L→P (PmrB) 44F→x (PmrB) |
| C-04/05-13 | E. coli | Influent in-house WWTP | 8 | AMP, CST, SMX | PIP, CST | 10L→R (PmrB) 12Q→x (PmrB) |
| C-04/05-15 | E. coli | Influent in-house WWTP | 8 | AM, CIP, CST, NAL, TMP | PIP, CIP, LVX | 15G→R (PmrA) 85T→A (PmrA) 2H→R (PmrB) |
| C-04/05-17 | E. coli | Influent in-house WWTP | 8 | AMP, CIP, CST, NAL | PIP, CIP, LVX, CST | 312D→N (PmrB) |
| C-04/07-03 | E. coli | Stunning facilities | 4 | AMP, CHL, CIP, CST, CTX, NAL, SMX, CAZ, TET, FEP, FOX | PIP, CST | − |
| C-04/07-06 | E. coli | Stunning facilities | 4 | AMP, CST, SMX, TET, TMP | PIP, CIP, LVX, SXT, FOF, CST | 29S→x (PmrB) |
| C-04/07-08 | E. coli | Stunning facilities | 4 | AMP, CST, SMX, TET, TMP | PIP, CIP, LVX, CHL, SXT, CST | − |
| Pig slaughterhouses and mWWTPs | ||||||
| C-03/02-02 | E. coli | Effluent in-house WWTP | 8 | AMP, CIP, CST, CTX, NAL, SMX, CAZ, TET, TMP, FEP | PP, CTX, CAZ, C/T, CIP, LVX, CHL, CST | 204A→x (PmrA) 2H→R (PmrB) |
| C-03/10-10 | E. coli | Influent municipal WWTP | 4 | CIP, CST, NAL | CST | 80A→V (PmrA) 285A→T (PmrB) 333H→Q (PmrB) |
| C-03/10-14 | E. coli | Influent municipal WWTP | 4 | CIP, CST, NAL | CST | 80A→V (PmrA) 285A→T (PmrB) 333H→Q (PmrB) |
| 03/10-43 | E. coli | Influent municipal WWTP | 16 | AMP. CIP, CST, CTX, NAL, SMX, CAZ, TMP, FEP | PIP, CTX, CAZ, SXT, CST | 44F→x (PmrB) 94P→S (PmrB) |
aAntimicrobial Susceptibility Testing Plates of German Federal Institute for Risk Assessment (BfR) containing sulfamethoxazole (SMX), trimethoprim (TMP), chloramphenicol (CHL), ciprofloxacin (CIP), nalidixic acid (NAL), tetracycline (TET), tigecycline (TGC), ertapenem (ETP), meropenem (MEM), imipenem (IMI), cefotaxime (CTX), ceftazidime (CAZ), cefoxitin (FOX), cefepime (FEP), colistin (CST), ampicillin (AMP), gentamicin (GEN). MIC were interpreted according to the epidemiological cut off values of EUCAST. bMicronaut-S MDR MRGN-Screening system containing temocillin (TEM), piperacillin (PIP), piperacillin/tazobactam (TZP), cefotaxime (CTX), ceftazidime (CAZ), imipenem (IMI), meropenem (MEM), amikacin (AMK), tigecycline (TGC), chloramphenicol (CHL), fosfomycin (FOF), trimethoprim/sulfamethoxazole (SXT), ciprofloxacin (CIP), levofloxacin (LVX), and colistin (CST). MIC were interpreted according to the clinical breakpoints of EUCAST. cPolymorphisms found for coding sequences for PmrA or PmrB.