Volume 11, Number 6—June 2005
Dispatch
Macrolide- and Telithromycin-resistant Streptococcus pyogenes, Belgium, 1999–20031
, Christine Lammens*, Sabine Chapelle*, Monique Wijdooghe*, Jasper Piessens*, Koen Van Herck*, and Herman Goossens*
Table 1
Yearly prevalence of Streptococcus pyogenes isolates screened and of macrolide-resistant S. pyogenes distributed by patient age group and isolate phenotype, 1999—2003
| 1999 | 2000 | 2001 | 2002 | 2003 | |
|---|---|---|---|---|---|
| Total S. pyogenes screened | 598 | 336 | 633 | 1,226 | 1,073 |
| Isolated from adults (mean age, 34.7 y; SD, 11.1 y; range, 17 to 91 y) | 220 (36.7%) | 144 (43.1%) | 245 (38.7%) | 469 (38.2%) | 453 (42.0%) |
| Isolated from children (mean age, 7.2 y; SD, 3.5 y; range, 3 mo to 16.9 y) | 357 (59.6%) | 172 (51.2%) | 367 (58.0%) | 675 (55.0%) | 552 (51.0%) |
| Macrolide-resistant S. pyogenes | 81 (14%) | 41 (12%) | 73 (12%) | 215* (18%) | 96* (9%) |
| Isolated from adults | 23 (4%) | 16 (5%) | 29 (5%) | 82 (7%) | 38† (4%) |
| Isolated from children | 56 (9%) | 22 (7%) | 44 (7%) | 126‡ (10%) | 50† (5%) |
| Constitutive phenotype | 49/81 (8%) | 10/41§ (3%) | 28/73 (4%) | 68/215 (6%) | 54/96 (5%) |
| M phenotype | 32/81 (5%) | 29/41 (9%) | 39/73 (6%) | 141/215 (12%) | 38/96§ (4%) |
| Inducible phenotype | – | 2/41 (1%) | 6/73 (1%) | 7/215 (1%) | 4/96 (0.4%) |
*Increase and decrease in macrolide resistance from 2001 to 2002 and from 2002 to 2003, respectively, was significant (p<0.001).
†Prevalence of macrolide-resistant S. pyogenes decreased significantly among both children and adults from 2002 to 2003 (p<0.0001).
‡Prevalence of macrolide-resistant S. pyogenes increased significantly among children from 2001 to 2002 (p = 0.005).
§Decrease in prevalence of cMLS isolates from 1999 to 2000 (p = 0.005) and of M phenotype isolates from 2002 to 2003 (p<0.0001) was significant. Pearson's χ2-test with Bonferonni post-hoc adjustments was used for all multiple comparisons. p<0.05 (2-sided) was significant.
1A preliminary account of this work was presented at the 44th Interscience Conference on Antimicrobial Agents and Chemotherapy, October 30–November 2, 2004, Washington DC, USA.