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Antimicrobial Agents and Chemotherapy, January 1999, p. 48-52, Vol. 43, No. 1
Antimicrobial Research Laboratory,
Received 21 April 1998/Returned for modification 3 July
1998/Accepted 5 October 1998
Streptococcus pyogenes isolates (group A streptococcus)
of different erythromycin resistance phenotypes were collected from all
over Finland in 1994 and 1995 and studied; they were evaluated for
their susceptibilities to 14 antimicrobial agents (396 isolates) and
the presence of different erythromycin resistance genes (45 isolates).
The erythromycin-resistant isolates with the macrolide-resistant but
lincosamide- and streptogramin B-susceptible phenotype (M phenotype)
were further studied for their plasmid contents and the transferability
of resistance genes. Resistance to antimicrobial agents other than
macrolides, clindamycin, tetracycline, and chloramphenicol was not
found. When compared to our previous study performed in 1990, the rate
of resistance to tetracycline increased from 10 to 93% among
isolates with the inducible resistance (IR) phenotype of macrolide,
lincosamide, and streptogramin B (MLSB) resistance. Tetracycline resistance was also found among 75% of the
MLSB-resistant isolates with the constitutive resistance
(CR) phenotype. Resistance to chloramphenicol was found for the first
time in S. pyogenes in Finland; 3% of the isolates with
the IR phenotype were resistant. All the chloramphenicol-resistant
isolates were also resistant to tetracycline. Detection of erythromycin
resistance genes by PCR indicated that, with the exception of one
isolate with the CR phenotype, all M-phenotype isolates had the
macrolide efflux (mefA) gene and all the
MLSB-resistant isolates had the erythromycin resistance
methylase (ermTR) gene; the isolate with the CR phenotype contained the ermB gene. No plasmid DNA could be isolated
from the M-phenotype isolates, but the mefA gene was
transferred by conjugation.
0066-4804/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Erythromycin Resistance Genes in Group A
Streptococci in Finland
and
*
Corresponding author. Mailing address: Antimicrobial
Research Laboratory, National Public Health Institute, P.O. Box 57, 20521 Turku, Finland. Phone: 358-2-2519255. Fax: 358-2-2519254. E-mail: janne.kataja{at}utu.fi.
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