TABLE 1.

Antibiotic susceptibility of 187 invasive macrolide-resistant S. pneumoniae strains

Antibiotic	Pre-PCV7 (1999-2001) (n = 54)						Early-PCV7 (2002-2004) (n = 65)							Late-PCV7 (2005-2007) (n = 68)
	MIC (μg/ml)			%I	%R	I+R	MIC (μg/ml)			%I	%R	I+R	Pa	MIC (μg/ml)			%I	%R	I+R	Pb
	MIC50	MIC90	Range				MIC50	MIC90	Range					MIC50	MIC90	Range
Penicillin
Old CLSI breakpointsc	0.5	2	≤0.016-2	48.2	27.8	76.0	0.5	2	≤0.016-2	50.7	23.1	73.8	0.79	0.12	2	≤0.016-2	44.1	10.3	54.4	0.01
New CLSI breakpointsd
Meningitis	0.5	2	≤0.016-2		76.0	76.0	0.5	2	≤0.016-2		73.8	73.8	0.79	0.5	2	≤0.016-2		54.4	54.4	0.01
Nonmeningitis	0.5	2	≤0.016-2	0	0	0	0.5	2	≤0.016-2	0	0	0		0.12	2	≤0.016-2	0	0	0
Cefotaximee
Meningitis	0.5	1	0.01-2	33.3	3.7	37.0	0.25	1	0.01-1	27.7	0	27.7	0.28	0.12	1	0.01-2	13.2	1.5	14.7	0.004
Nonmeningitis	0.5	1	0.01-2	3.7	0	3.7	0.25	1	0.01-1	0	0	0	0.20	0.12	1	0.01-2	1.5	0	1.5	0.09
Erythromycin	>256	>256	4->256	0	100	100	>256	>256	4->256	0	100	100		>256	>256	1->256	0	100	100
Clindamycin	>0.5	>0.5	≤0.25->0.5	0	96.2	96.2	>0.5	>0.5	≤0.25->0.5	0	87.7	87.7	0.09	>0.5	>0.5	≤0.25->0.5	0	88.3	88.3	0.11
Tetracycline	32	64	≤0.25-64	1.9	88.9	90.8	16	64	0.25-128	1.5	75.3	76.8	0.05	8	32	0.25-64	2.9	77.9	80.8	0.13
Chloramphenicol	4	16	≤2-16		50.0	50.0	4	16	≤2-16		35.4	35.4	0.10	≤2	16	≤2-32		29.4	29.4	0.02
Cotrimoxazole	>2	>2	≤0.5->2	9.3	53.7	63.0	>2	>2	≤0.5->2	1.5	58.5	60	0.74	≤0.5	>2	≤0.5->2	2.9	33.8	36.7	<0.001

^aP value comparing pre-PCV7 to early-PCV7 periods.

^bP value comparing pre-PCV7 to late-PCV7 periods.

^cOld penicillin breakpoints: sensitive ≤ 0.06 μg/ml, intermediate = 0.12 to 1 μg/ml, and resistant ≥ 2 μg/ml.

^dNew penicillin breakpoints: meningeal sensitive ≤ 0.06 μg/ml and resistant ≥ 0.12 μg/ml, and nonmeningeal sensitive ≤ 2 μg/ml; intermediate: 4 μg/ml, resistant ≥ 8 μg/ml.

^eCefotaxime breakpoints: meningeal sensitive ≤ 0.5 μg/ml, intermediate = 1 μg/ml, and resistant ≥ 2 μg/ml, nonmeningeal sensitive ≤ 1 μg/ml, intermediate = 2 μg/ml, and resistant ≥ 4 μg/ml.