Antibiotic susceptibilities of invasive group A streptococci in England, Wales and Northern Ireland: a comparison of results between hospital laboratories and the national reference laboratories
Abstract number: 902_p1089
To compare antimicrobial susceptibilities of invasive GAS isolates reported from hospital laboratories with data generated from the Streptococcus and Diphtheria Reference Unit (SDRU) and the Antibiotic Resistance Monitoring and Reference Laboratory (ARMRL). The distribution of antibiotic resistance will also be determined against denominator and typing data (M or emm types).
Laboratories in England, Wales and Northern Ireland report cases of invasive GAS disease weekly to the Communicable Disease Surveillance Centre. This includes demographic, clinical and microbiological data. Isolates are also submitted to the national reference laboratories and subjected to M typing and antimicrobial testing. Datasets from both sources during the period January to July 2003 were reconciled and analysed. Data used in this analysis included age (in 10 year bands), sex, laboratory, region, site of isolation and GAS type.
A total of 812 invasive GAS isolates were reported by hospital laboratories and received by SDRU between January and July 2003; 723 of these had antimicrobial results. A total of 98.3% (711/723) had been tested by both hospital laboratories and ARMRL; the susceptibilities correlated exactly for all four antibiotics. No penicillin resistance was reported, but 0.7% (5/723) were resistant to clindamycin, 4.0% (29/723) to erythromycin and 13.6% (98/723) to tetracycline. Furthermore, six erythromycin and tetracycline resistant strains were reported, three erythromycin and clindamycin resistant, and two were erythromycin, tetracycline and clindamycin resistant strains. Tetracycline resistance was higher in the younger age groups, peaking at 22.0% (29/132) in 3039 years olds (P = 0.09). Tetracycline resistance was observed in 16.8% (59/351) males compared with 9.3% (29/311) females (P = 0.018). GAS M types emm43 (10/11), M77 (4/5), M83 (28/31) and emm91 (3/3) appeared to be associated with tetracycline resistance (P < 0.000).
An improvement was noted in the number of invasive GAS cases reported from laboratories, which included antibiotic susceptibility data; from 81% in 2002 to 87.6% during January to July 2003. There was also excellent correlation between these data and the ARMRL results. Erythromycin and tetracycline resistance rates were similar to previous years."
|Session name:||XXIst ISTH Congress|
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