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Antimicrobial Agents and Chemotherapy, June 1998, p. 1493-1494, Vol. 42, No. 6
Antimicrobial Research Laboratory,
Received 10 November 1997/Returned for modification 21 January
1998/Accepted 25 March 1998
Different mechanisms of erythromycin resistance predominate in
group C and G streptococcus (GCS and GGS, respectively) isolates collected from 1992 to 1995 in Finland. Of the 21 erythromycin-resistant GCS and 32 erythromycin-resistant GGS isolates,
95% had the mefA or mefE drug efflux gene and
94% had the ermTR methylase gene, respectively.
Lancefield group C and G
streptococci (GCS and GGS, respectively) may cause pharyngitis and a
variety of severe infections in humans (9, 19). For
penicillin-allergic patients, erythromycin has long been a good
alternative in the treatment of streptococcal infections. Resistance to
erythromycin in group A streptococci (GAS) has been reported from a
number of countries (6, 11, 15), but there are few reports
of erythromycin resistance in GCS and GGS (1, 20).
The two presently recognized mechanisms for resistance to macrolide
antibiotics in streptococci are target-site modification and
active-drug efflux. Target-site modification is mediated by an
erythromycin resistance methylase (erm) that reduces binding of macrolide, lincosamide, and streptogramin B (MLS) antibiotics to the
target site in the 50S ribosomal subunit (5). The phenotypic expression of MLS resistance can be inducible (IR) or constitutive (CR). In active-drug efflux, the protein encoded by the mefA
or mefE (macrolide efflux) gene causes resistance to
14- and 15-membered macrolide compounds only (3, 18). This
phenotype is called the M phenotype (17).
In the present study, we investigated the susceptibilities of GCS and
GGS to erythromycin and three other antimicrobials and determined the
erythromycin resistance mechanism in the isolates resistant to
erythromycin.
From January 1992 through December 1995, a total of 579 clinical
isolates of GCS and 911 clinical isolates of GGS were collected from
throat swab and pus samples in the microbiological laboratory of the
Central Hospital of Pohjois-Karjala in Joensuu, Finland, and sent to
the Antimicrobial Research Laboratory of the National Public Health
Institute, Turku, Finland. Identification of The IR, CR, and M phenotypes of erythromycin-resistant GCS and GGS
isolates were determined by the double-disk test by using erythromycin
and clindamycin disks as described previously (12).
For the detection of different erythromycin resistance genes in the
genomes of GCS and GGS by PCR, DNA was extracted as described previously (14). The DNAs of the erythromycin-resistant
isolates were amplified with primers specific for the ermA,
ermB, ermC, and mefA or -E
genes; PCR conditions for the primer sets were as described previously
(16, 3). Primers used for the detection of the
ermTR gene were designed on the basis of the sequence of ermTR (13) as follows:
5'-ATAGAAATTGGGTCAGGAAAAGG-3' (TR1) and 5'-TTGATTTTTAGTAAAAAG-3' (TR2). The PCR mixture
was as described previously (13). A total of 35 cycles were
carried out with a thermal reactor (model HB-TR1; Hybaid Ltd.,
Middlesex, United Kingdom) as follows: denaturation at 94°C for
30 s, annealing at 42°C for 60 s, and elongation at 72°C
for 90 s. To confirm that TR1 and TR2 had
amplified the ermTR gene, the PCR products obtained by using
these primers were digested with HinfI endonuclease (Promega
Co., Madison, Wis.) under conditions recommended by the manufacturer.
The DNAs containing erythromycin resistance genes from
Staphylococcus aureus RN2864 (7),
Clostridium perfringens CP592 (2),
Staphylococcus aureus IHT 62242, Streptococcus
pyogenes A200 (13), and S. pyogenes A569
were used as positive controls in the PCR-based detection of the
ermA, ermB, ermC, ermTR,
and mefA or -E genes, respectively. After the
amplification, the detection and visualization of the PCR products were
performed as described previously (10). Amplification of the
DNAs from the positive controls with the corresponding primers produced
PCR products of expected sizes; ermA, ermB, and
ermC were 640 bp, ermTR was 530 bp, and
mefA or -E was 1.4 kb. Digestion of the PCR
products obtained with the TR1 and TR2 primers
from the control strain produced bands with lengths of 355, 128, and 54 bp, as expected.
Susceptibility results.
The proportions of the GCS and GGS
isolates resistant to erythromycin (3.6 and 3.5%, respectively) and
clindamycin (1.0 and 0.3%, respectively) were similar, but the
proportion of GCS isolates resistant to tetracycline was clearly lower
than that of GGS isolates (13 versus 43%). All isolates were
susceptible to penicillin (Table 1).
Tetracycline resistance was found in 2 (10%) and 16 (50%) of the 21 erythromycin-resistant GCS and 32 GGS isolates, respectively, which
parallels the common tetracycline resistance level well. Hence, it
seems that tetracycline resistance in GCS or GGS is not linked to
erythromycin resistance.
0066-4804/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Different Erythromycin Resistance Mechanisms in
Group C and Group G Streptococci
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ABSTRACT
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-hemolytic isolates was
performed by a commercial latex-agglutination technique (Streptex;
Wellcome, Dartford, England). The MICs of erythromycin, clindamycin,
tetracycline, and penicillin (Sigma Chemical Co. Ltd., St. Louis, Mo.)
were determined by the plate dilution method according to the
recommendations of the National Committee for Clinical Laboratory
Standards (8) as described previously (12). The
breakpoints for resistance were as follows: erythromycin and clindamycin,
1 µg/ml (8); penicillin,
4 µg/ml
(8); and tetracycline,
8 µg/ml (8). The
control strains were those described previously (11).
TABLE 1.
MICs of four antibiotics for 579 GCS isolates and 911 GGS isolates
Erythromycin resistance phenotypes and genes. Nearly all (95%) of the erythromycin-resistant GCS isolates had the M phenotype, whereas 91 and 6% of the erythromycin-resistant GGS isolates had the IR and the CR phenotype, respectively.
All isolates with the M phenotype were positive with primers specific for the mefA or -E gene. Likewise, the ermTR gene was found in all IR phenotype isolates. Of the CR phenotype isolates, one had the ermTR gene and the other had the ermB gene. Hence, 20 (95%) of the 21 erythromycin-resistant GCS isolates had the mefA or -E gene, and the mechanism conveyed by this gene has been shown to be active-drug efflux (17). As 30 (94%) of the 32 erythromycin-resistant GGS isolates had the ermTR gene and one GGS isolate had the ermB gene, altogether 31 (97%) of the 32 GGS isolates had an erm gene, and the mechanism of resistance is therefore proposed to be target-site modification. The mefA gene was first identified in GAS (16), and we have also found it in GAS with the M phenotype (4). The ermTR gene in GAS A200 was recently characterized by us (13), and we have found it to be common in Finland among GAS with the IR phenotype (4). This study is the first to show that the ermTR gene and the mefA or -E gene may exist in other
-hemolytic streptococcus species as well.
Because the erythromycin resistance genes are the same in GCS, GGS, and
GAS in Finland, it is possible that the genes have transferred among
these species. Although there is an association between the
active-efflux mechanism and GCS in Finland, it is possible that this
association is not a universal phenomenon. In Taiwan the MIC results
showed that 33.3% of the GCS isolates were resistant to clindamycin
(20), which is related to MLS resistance (12).
In summary, different mechanisms of erythromycin resistance predominate
in GCS and GGS isolates in Finland.
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ACKNOWLEDGMENTS |
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We are indebted to Minna Lamppu, Tarja Laustola, Anna-Liisa Lumiaho, and Tuula Randell for expert technical assistance and to Monica Österblad for editorial assistance.
This work was supported by the Sigrid Juselius Foundation (funds to J. Kataja and H. Seppälä), the Maud Kuistila Foundation (funds to H. Seppälä), and the Scandinavian Society for Antimicrobial Chemotherapy (funds to P. Huovinen).
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FOOTNOTES |
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* 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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REFERENCES |
|---|
|
|
|---|
| 1. | Barnham, M., and G. Cole. 1986. Erythromycin-resistant beta-haemolytic streptococci in North Yorkshire. J. Infect. 13:200-202[Medline]. |
| 2. |
Berryman, D. I., and J. I. Rood.
1989.
Cloning and hybridization analysis of ermP, a macrolide-lincosamide-streptogramin B resistance determinant from Clostridium perfringens.
Antimicrob. Agents Chemother.
33:1346-1353 |
| 3. | Clancy, J., J. Petitpas, F. Dib-Hajj, W. Yuan, M. Cronan, A. V. Kamath, J. Bergeron, and J. A. Retsema. 1996. Molecular cloning and functional analysis of a novel macrolide-resistance determinant, mefA, from Streptococcus pyogenes. Mol. Microbiol. 22:867-879[Medline]. |
| 4. | Kataja, J., P. Huovinen, M. Skurnik, and H. Seppälä. Unpublished data. |
| 5. |
Leclercq, R., and P. Courvalin.
1991.
Bacterial resistance to macrolide, lincosamide, and streptogramin antibiotics by target modification.
Antimicrob. Agents Chemother.
35:1267-1272 |
| 6. |
Mitsuhashi, S.,
M. Inoue,
K. Saito, and M. Nakae.
1982.
Drug resistance in Streptococcus pyogenes strains isolated in Japan, p. 151-154.
In
D. Schlessinger (ed.), Microbiology 1982. American Society for Microbiology, Washington, D.C.
|
| 7. | Murphy, E., and S. Löfdahl. 1984. Transposition of Tn554 does not generate a target duplication. Nature 307:292-294[Medline]. |
| 8. | National Committee for Clinical Laboratory Standards. 1997. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically, fourth edition. Approved Standard M7-A4. National Committee for Clinical Laboratory Standards, Wayne, Pa. |
| 9. | Salata, R. A., P. I. Lerner, D. M. Shlaes, K. V. Gopalakrishna, and E. Wolinsky. 1989. Infections due to Lancefield group C streptococci. Medicine (Baltimore) 68:225-239[Medline]. |
| 10. |
Seppälä, H.,
Q. He,
M. Österblad, and P. Huovinen.
1994.
Typing of group A streptococci by random amplified polymorphic DNA analysis.
J. Clin. Microbiol.
32:1945-1948 |
| 11. | Seppälä, H., A. Nissinen, H. Järvinen, S. Huovinen, T. Henriksson, E. Herva, S. E. Holm, M. Jahkola, M.-L. Katila, T. Klaukka, S. Kontiainen, O. Liimatainen, S. Oinonen, L. Passi-Metsomaa, and P. Huovinen. 1992. Resistance to erythromycin in group A streptococci. N. Engl. J. Med. 326:292-297[Abstract]. |
| 12. |
Seppälä, H.,
A. Nissinen,
Q. Yu, and P. Huovinen.
1993.
Three different phenotypes of erythromycin-resistant Streptococcus pyogenes in Finland.
J. Antimicrob. Chemother.
32:885-891 |
| 13. |
Seppälä, H.,
M. Skurnik,
H. Soini,
M. C. Roberts, and P. Huovinen.
1998.
A novel erythromycin resistance methylase gene (ermTR) in Streptococcus pyogenes.
Antimicrob. Agents Chemother.
42:257-262 |
| 14. | Seppälä, H., J. Vuopio-Varkila, M. Österblad, M. Jahkola, M. Rummukainen, S. E. Holm, and P. Huovinen. 1994. Evaluation of methods for epidemiologic typing of group A streptococci. J. Infect. Dis. 169:519-525[Medline]. |
| 15. | Stingemore, N., G. R. J. Francis, M. Toohey, and D. B. McGechie. 1989. The emergence of erythromycin resistance in Streptococcus pyogenes in Fremantle, Western Australia. Med. J. Aust. 159:626-631. |
| 16. | Sutcliffe, J., T. Grebe, A. Tait-Kamradt, and L. Wondrack. 1996. Detection of erythromycin-resistant determinants by PCR. Antimicrob. Agents Chemother. 40:2562-2566[Abstract]. |
| 17. | Sutcliffe, J., A. Tait-Kamradt, and L. Wondrack. 1996. Streptococcus pneumoniae and Streptococcus pyogenes resistant to macrolides but sensitive to clindamycin: a common resistance pattern mediated by an efflux system. Antimicrob. Agents Chemother. 40:1817-1824[Abstract]. |
| 18. | Tait-Kamradt, A., J. Clancy, M. Cronan, F. Dib-Hajj, L. Wondrack, W. Yuan, and J. Sutcliffe. 1997. MefE is necessary for the erythromycin-resistant M phenotype in Streptococcus pneumoniae. Antimicrob. Agents Chemother. 41:2251-2255[Abstract]. |
| 19. | Vartian, C., P. I. Lerner, D. M. Shlaes, and K. V. Gopalakrishna. 1985. Infections due to Lancefield group G streptococci. Medicine 64:75-88[Medline]. |
| 20. | Wu, J.-J., K.-Y. Lin, P.-R. Hsueh, J.-W. Liu, H.-I. Pan, and S.-M. Sheu. 1997. High incidence of erythromycin-resistant streptococci in Taiwan. Antimicrob. Agents Chemother. 41:844-846[Abstract]. |
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