Table 3 (Adapted from [14, 15]) usual breakpoints and susceptibility of ESBL-producing Enterobacteriaceae

Third-generation cephalosporins

Escherichia coli: < 10%

Klebsiella species: 3%

EUCAST: S ≤ 1

CLSI: S ≤ 1

+++

Only for targeted therapy or de-escalation

MIC required

Cefepime

E. coli: 5–30%

K. pneumoniae: 5–60%

EUCAST: S < 1

CLSI: S ≤ 2

+++

Frequent failure if MICs > 1 mg/L

MIC required

Cefoxitin

E. coli: 80%

EUCAST: NA

++

PK optimization

Ceftolozane–tazobactam

E. coli: 85–95%

K. pneumoniae: 40–65%

EUCAST: S ≤ 1

CLSI: S ≤ 8

?

Ceftazidime–avibactam

E. coli: 98–100%

K. pneumoniae: 90–100%

EUCAST: S ≤ 8

CLSI: S ≤ 8

?

Probably as effective as carbapenems

Temocillin

E. coli 61% (CMI ≤ 8)

E. coli 99% (CMI ≤ 32)

EUCAST: S ≤ 8

EUCAST: S ≤ 32 (urinary)

CLSI: S ≤ 8

CLSI: S ≤ 32 (urinary)

±

PK optimization (high dosage and prolonged infusion)