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Volume 19, Number 7—July 2013

Research

Pneumococcal Serotypes before and after Introduction of Conjugate Vaccines, United States, 1999–20111

Sandra S. RichterComments to Author , Kristopher P. Heilmann, Cassie L. Dohrn, Fathollah Riahi, Daniel J. Diekema, and Gary V. Doern
Author affiliations: Cleveland Clinic, Cleveland, Ohio, USA (S.S. Richter); University of Iowa Carver College of Medicine, Iowa City, Iowa, USA (K.P. Heilmann, C.L. Dohrn, F. Riahi, D.J. Diekema, G.V. Doern)

Main Article

Table 1

Patient demographics and penicillin susceptibility for Streptococcus pneumoniae isolates, United States, 1999–2011*

Characteristic No. (%) isolates
Before PCV7, 1999–2000, n = 1,506 Post-PCV7, 2004–2005, n = 1,647 Post-PCV7, 2008–2009, n = 1,946 Post-PCV13, 2010–2011, n = 1,750
Medical center location
Northeast 390 (26) 470 (29) 495 (25) 395 (23)
Midwest 394 (26) 403 (24) 395 (20) 433 (25)
Southeast 224 (15) 281 (17) 343 (18) 340 (19)
Southwest 300 (20) 265 (16) 414 (21) 396 (23)
West
198 (13)
228 (14)
299 (15)
186 (11)
Patient location
Inpatient 846 (56) 995 (60) 1,056 (54) 987 (56)
Outpatient 654 (43) 624 (38) 817 (42) 734 (42)
Unknown
6 (0.4)
28 (2)
73 (4)
29 (2)
Age, y
0–5† 442 (29) 328 (20) 417 (21) 367 (21)
6–20 86 (6) 137 (8) 160 (8) 173 (10)
21–64 627 (42) 769 (47) 861 (44) 824 (47)
≥65 336 (22) 350 (21) 425 (22) 376 (21)
Unknown
15 (1)
63 (4)
83 (4)
10 (0.6)
Specimen source
Blood‡ 460 (31) 406 (25) 454 (23) 428 (24)
Cerebrospinal fluid 20 (1) 14 (1) 19 (1) 16 (1)
Other sterile body fluid –§ 16 (1) 31 (2) –§
Middle ear fluid 125 (8) 126 (8) 118 (6) 110 (6)
Lower respiratory tract 670 (44) 870 (53) 953 (49) 840 (48)
Sinus 44 (3) 91 (6) 144 (7) 147 (8)
Other
187 (12)
124 (8)
227 (12)
209 (12)
Penicillin (all isolates)
Susceptible (MIC ≤0.06 µg/mL)¶ 1,005 (67) 1,112 (68) 1,213 (62) 1,066 (61)
Intermediate (MIC 0.12–1 µg/mL)# 178 (12) 295 (18) 403 (21) 352 (20)
Resistant (MIC ≥2 µg/mL)**
323 (21)
240 (15)
330 (17)
332 (19)
Penicillin (noninvasive isolates, oral breakpoint)
Susceptible (MIC ≤0.06 µg/mL) 652 (64) 793 (65) 828 (57) 747 (57)
Intermediate (MIC 0.12–1 µg/mL) 127 (12) 221 (18) 329 (23) 279 (21)
Resistant (MIC ≥2 µg/mL)
247 (24)
197 (16)
285 (20)
280 (21)
Penicillin (all invasive isolates, meningitis parenteral breakpoint)
Susceptible (MIC ≤0.06 µg/mL) 353 (74) 319 (73) 385 (76) 319 (72)
Resistant (MIC ≥0.12 µg/mL)
127 (26)
117 (27)
119 (24)
125 (28)
Penicillin (invasive isolates, CSF excluded, nonmeningitis parenteral breakpoint)
Susceptible (MIC ≤2 µg/mL) 442 (96) 400 (95) 458 (94) 392 (92)
Intermediate (MIC 4 µg/mL) 18 (4) 22 (5) 26 (5) 35 (8)
Resistant (MIC ≥8 µg/mL) 0 0 1 (0.2) 1 (0.2)

*PCV7, pneumococcal conjugate 7-valent vaccine; PCV13, pneumococcal conjugate 13-valent vaccine.
†Significant decrease from 29% in the preconjugate vaccine period to 20%–21% in the postconjugate vaccine period (p<0.001).
‡Significant decrease from 31% in 1999–2000 to 23%–25% in the postconjugate vaccine period (p<0.01).
§Other sterile body fluids were not recorded as a separate specimen source category during these 2 periods.
¶Penicillin susceptible: parenteral therapy for meningitis or oral therapy.
#Penicillin intermediate: oral therapy, resistant if parenteral therapy for meningitis.
**Penicillin resistant: parenteral therapy for meningitis or oral therapy.

Main Article

1Presented in part at the 112th General Meeting of the American Society for Microbiology Annual Meeting, June 19, 2012, San Francisco, CA, USA (abstract no. 2986).

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