Table 5.

Comparison of three national antimicrobial resistance surveillance studies

PeriodNo. of medical centersNo. of isolatesAge distribution (%)Source (%)aAntimicrobial resistance (%)bMultiresistance (%)c,f
0–5 yr6–20 yr21–64 yr≥65 yrURTLRTBlood/CSF/BFOtherPenicillincErythromycincClindamycincTetracyclineaTMP-SMXcChloramphenicolc,dCiprofloxine
1994–1995 30 1,527 32.9 6.9 36.523.4 18.0 41.6 40.1 0.1 23.6 (14.1, 9.5)10.3 (0.1, 10.2) Not tested7.6 (0.1, 7.5) 26.8 (8.4, 18.4) 4.3 1.2 9.1
1997–1998 34 1,601 27.0 6.1 40.8 25.414.9 48.3 35.5 1.3 29.5 (17.4, 12.1)19.2 (0.4, 18.9) 5.7 (0.1, 5.6) 13.2 (0.3, 12.9)31.0 (10.7, 20.4) 7.2 1.6 16.0
1999–2000 331,531 29.2 5.7 42.0 22.1 21.3 44.5 32.12.2 34.2 (12.7, 21.5) 26.2 (0.5, 25.7)19.2 (0.3, 8.9) 16.6 (0.3, 16.3) 35.9 (5.6, 30.3)8.3 1.4 22.4
  • a URT, upper respiratory tract; LRT, lower respiratory tract; CSF/BF, cerebrospinal fluid/normally sterile body fluid.

  • b Intermediate plus high-level resistance; values in parentheses are intermediate and high-level resistance rates, respectively.

  • c Overall resistance rates were significantly higher (P < 0.001) in 1999–2000 than in 1994–1995 for penicillin, erythromycin, clindamycin, tetracycline, TMP-SMX, chloramphenicol, and multiresistant isolates.

  • d Only high-level resistance category, no intermediate resistance.

  • e 1,523 isolates tested from 1994–1995; 1,596 isolates tested from 1997–1998; MIC of ≥4 μg/ml used to determine resistance.

  • f Multiresistance is defined as intermediate or high-level penicillin resistance plus intermediate or high-level resistance to at least two non-beta-lactam agents.