Piperacillin Tazobactam – Injection products

Recognized Interpretive Criteria

FDA Identified Interpretive Criteria

	Minimum Inhibitory Concentrations (mcg/mL)				Disk Diffusion (zone diameter in mm)
Pathogen	S	SDD^a	I	R	S	SDD^a	I	R
Enterobacterales^b	≤8/4	-	16/4	≥32/4	≥25	-	21-24	≤20
Pseudomonas aeruginosa	≤8/4	16/4	-	≥32/4	≥23	19-22	-	≤18
Acinetobacter spp.	M100 standard is recognized
Haemophilus influenzae and parainfluenzae	M100 standard is recognized
Anaerobes	M100 standard is recognized				-	-		-

S = Susceptible; SDD=Susceptible-dose dependent; I = Intermediate; R = Resistant

^a Susceptible-dose dependent breakpoints are based on a dosage regimen of 4.5 grams every 6 hours as a 3-hour infusion in patients with creatinine clearance 41-120 mL/min.

^b Clinical efficacy was shown for E. coli and K. pneumoniae

Exception to the recognized standard of CLSI M100

For the bacteria listed below, susceptibility test interpretive criteria are not recognized at this time:

Other Non-Enterobacterales