TABLE 1.

Susceptibility of all S. pneumoniae isolates to antimicrobials according to penicillin susceptibility status (n = 4,940) from 1999

Antimicrobial agent and penicillin susceptibility statusa	MIC (μg/ml)g				% of isolatesb:
	Range	50%	90%	Mode	S	I	R
Penicillin
All	≤0.06->32	≤0.06	2	≤0.06	64.6	19.3	16.2
Pen-S	≤0.06	≤0.06	≤0.06	≤0.06	100	0	0
Pen-I	0.12-1	0.5	1	1	0	100	0
Pen-R	2->32	2	4	2	0	0	100
Amoxicillin-clavulanatec
All	≤0.03-16	≤0.03	2	≤0.03	77.9 (94.6)	9.9 (3.4)	12.2 (2.0)
Pen-S	≤0.03-0.25	≤0.03	≤0.03	≤0.03	100 (100)	0 (0)	0 (0)
Pen-I	≤0.03-8	0.5	1	0.5	68.3 (98.5)	23.2 (1.3)	8.5 (0.2)
Pen-R	0.5-16	2	8	2	0.9 (68.4)	33.5 (19.7)	65.6 (11.9)
Cefuroxime
All	≤0.25->16	≤0.25	8	≤0.25	70.1	1.9	28.1
Pen-S	≤0.25-4	≤0.25	≤0.25	≤0.25	99.8	0.1	0.0d
Pen-I	≤0.25->16	2	4	4	29.1	9.3	61.6
Pen-R	2->16	8	16	8	0	0	100
Ceftriaxonee
All	≤0.03-16	≤0.03	1	≤0.03	82.7 (96.4)	13.7 (2.1)	3.6 (1.5)
Pen-S	≤0.03-0.5	≤0.03	0.06	≤0.03	100 (100)	0 (0)	0 (0)
Pen-I	≤0.03-4	0.5	1	0.5	89.7 (99.3)	9.6 (0.6)	0.7 (0.1)
Pen-R	0.5-16	1	2	1	8.1 (78.6)	73.5 (12.4)	21.4 (9.0)
Azithromycin
All	≤0.06->32	≤0.06	6	≤0.06	74.9	3.7	21.4
Pen-S	≤0.06->32	≤0.06	≤0.12	≤0.06	94.5	0.7	4.8
Pen-I	≤0.06->32	1	>32	≤0.06	49.8	7.9	42.3
Pen-R	≤0.06->32	2	>32	>32	26.7	11.0	62.3
SXT
All	≤0.03->4	0.25	>4	0.25	63.3	6.5	30.3
Pen-S	≤0.03->4	0.25	1	0.25	86.7	5.3	8.1
Pen-I	0.06->4	4	>4	>4	33.0	11.0	56.0
Pen-R	0.06->4	4	>4	>4	5.9	5.9	88.2
Levofloxacin
All	≤0.008-32	0.5	1	0.5	99.3	0.1	0.6
Pen-S	≤0.008-16	0.5	1	0.5	99.3	0.1	0.6
Pen-I	0.25-16	0.5	1	0.5	99.4	0	0.6
Pen-R	0.25-32	0.5	1	0.5	99.0	0.1	0.9
Moxifloxacinf
All	≤0.008-4	0.12	0.12	0.12	99.5	0.4	0.1
Pen-S	≤0.008-4	0.12	0.12	0.12	99.5	0.5	0.1
Pen-I	0.03-4	0.12	0.12	0.12	99.7	0.2	0.1
Pen-R	0.06-4	0.12	0.12	0.12	99.2	0.5	0.3
Vancomycin
All	≤0.12-1	0.25	0.5	0.25	100	-h	-
Pen-S	≤0.12-1	0.25	0.5	0.25	100	-	-
Pen-I	≤0.12-1	0.25	0.5	0.25	100	-	-
Pen-R	≤0.12-1	0.25	0.5	0.25	100	-	-

^aA total of 3,189 isolates were penicillin susceptible (Pen-S), 952 were penicillin intermediate (Pen-I), and 799 were penicillin resistant (Pen-R).

^bS, susceptible; I, intermediate; R, resistant.

^cNCCLS 1999 breakpoints (16) were used to interpret data for amoxicillin-clavulanate. Interpreted data utilizing NCCLS 2002 breakpoints (18) are shown in parentheses.

^dActual percent resistance was 0.02%.

^eNCCLS 1999 breakpoints (16) were used to interpret data for ceftriaxone. Interpreted data utilizing NCCLS 2002 interpretations (18) are shown in parentheses.

^fNCCLS 2002 breakpoints (18) were used to interpret data for moxifloxacin.

^g50% and 90%, MIC₅₀ and MIC₉₀, respectively.

^h-, no NCCLS criteria (18) available for I and R category intrepretations.