Does the adoption of EUCAST susceptibility breakpoints affect the selection of antimicrobials to treat acute community-acquired respiratory tract infections?

Table 2 Antimicrobial susceptibility of S. pneumoniae as classified by CLSI and EUCAST §

Antimicrobial agent^a(n° of strains)	CLSI susceptibility breakpoint (mg/L)	EUCAST susceptibility breakpoint(mg/L)	CLSI %S	EUCAST %S	Type of discrepancy^b
Benzyl-penicillin (37.642)	≤2*^c	≤1**	94.2	87.4	minor
Amoxicillin-clavulanate (2725)	≤2	≤0.5***	99.2	87.6	major
Cefaclor (2.581)	≤1	≤0.032	92.3	0.5	very major
Cefpodoxime (5.725)	≤0.5	≤0.25	84.1	82.5	minor
Cefuroxime axetil (32.729)	≤1	≤0.25	79.6	73.6	minor
Cefotaxime (12.800)	≤1^c	≤0.5	99.3	97.6	minor
Ceftriaxone (3.138)	≤1^c	≤0.5	98.4	89.7	minor
Meropenem (575)	≤0.25^c	≤2	97.7	99.8	minor
Ertapenem (3.680)	≤1	≤0.5	99.7	99.0	-
Imipenem (1.643)	≤0.12	≤2	95.4	99.9	minor
Moxifloxacin (26.746)	≤1	≤0.5	98.5	98.4	-
Ofloxacin (4.412)	≤2	≤0.125	95.4	0.0	very major
Azithromycin (63.481)	≤0.5	≤0.25	69.1	68.8	-
Telithromycin (7.034)	≤1	≤0.25	99.4	95.9	minor
Clindamycin (38.126)	≤0.25	≤0.5	81.4	81.6	-
Vancomycin (51.053)	≤1	≤2	99.8	100	-

§ CLSI [11] and EUCAST [13].
^aFor Cefuroxime parenteral, Levofloxacin, Erythromycin and Clarithromycin, CLSI and EUCAST suggested the same susceptibility breakpoints.
^bDiscrepancy as defined in the materials and methods section.
^cBreakpoint refers to non meningeal infections.
* breakpoint refers to a dosage of 2 million units 6 times daily.
** breakpoint refers to a dosage of 2.4 gm 4 times or 1.2 gm 6 times daily.
*** breakpoint refers to Ampicillin. The rate of susceptibiliy to Amoxicillin-clavulanate has been inferred from the rate of susceptibility to Ampicillin.

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