Susceptibility to Telithromycin in 1,011 Streptococcus pyogenes Isolates from 10 Central and Eastern European Countries

In 540 beta-hemolytic streptococci, the rates of resistance to tetracycline, chloramphenicol, erythromycin, and clindamycin were 80.0, 22.8, 20.2, and 19.1%, respectively. Of the erythromycin-resistant isolates, 63.3% had the constitutive macrolide-lincosamide-streptogramin B (MLS B ) resistance phenotype, 23.9% had the M phenotype, and 12.8% had the inducible MLS B resistance phenotype. The constitutive MLS B resistance phenotype with the erm(B) gene was dominant in Korea.Current practice guidelines for the management of pharyngitis caused by Streptococcus pyogenes include the use of erythromycin as an alternative to penicillin when indicated and clindamycin for persons with multiple recurrent episodes (5). Macrolide or lincosamide therapy is also a recommended treatment option for S. agalactiae infection or for prophylaxis when streptococcal colonization among pregnant women is suspected (16). However, recent studies have shown that changes in the susceptibility of beta-hemolytic streptococci (BHS) to erythromycin and clindamycin have been substantial, although differences in rates of resistance to these agents have existed according to geographical location and investigators. The objectives of the present study were to investigate the incidence and possible trends in susceptibility among the BHS isolated from clinical specimens in a Korean hospital and to clarify the phenotypes and genotypes of erythromycin-resistant isolates.A total of 540 strains of BHS were collected from clinical specimens between January 1990 and December 2000 at Wonju Christian Hospital, a 1,000-bed teaching hospital in South Korea. Multiple isolates from the same patient were avoided. The isolates were identified by standard methods. Beta-hemolytic strains with group F antigens were excluded. Susceptibility to penicillin G, erythromycin, clindamycin, tetracycline, ceftriaxone (Sigma Chemical Co., St. Louis, Mo.), vancomycin (Daewoong Lilly, Seoul, Korea), and chloramphenicol (Chongkundang, Seoul, Korea) was tested by the agar dilution method (14). The resistance phenotypes of erythromycin-resistant (intermediate and resistant) isolates were determined by the double-disk test with erythromycin (15 g) and clindamycin (2 g) disks (17). The presence of erm and mef class genes was determined by PCR amplification with previously described primers (11,18) specific for erm(A) subclasses erm(TR), erm(B), erm(C), and mef(A).The overall resistance rates of BHS were found to be 80.0% for tetracycline, 22.8% for chloramphenicol, 20.2% for erythromycin, and 19.1% for clindamycin, whereas all isolates were susceptible to penicillin G, ceftriaxone, and vancomycin (Table 1). The rates of resistance to erythromycin found in this study were as follows, in order of decreasing rank: S. agalactiae, 25.3%; S. pyogenes, 16.1%; group C streptococci, 9.1%; group G streptococci, 9.0%. S. agalactiae had the highest rate of clindamycin resistance (28.2%), followed by S. pyogenes (9.8%), group C streptococci (4.5%), and group G streptococci (1.5%

Section: Specific For Erm(a) Subclasses Erm(tr) Erm(b) Erm(c) and mentioning

confidence: 99%

Antimicrobial Susceptibility Patterns and Macrolide Resistance Genes of β-Hemolytic Streptococci in Korea

Uh¹,

Jang²,

Hwang³

et al. 2004

“…In Portugal, where penicillin V is not available, macrolides and lincosamides have the additional advantage of being a therapeutic option with an oral route of administration. High macrolide resistance in GAS was previously identified in Portugal (13) in line with other European countries (1,4,6) but in contrast to others (14,16). The aims of this study were to determine the prevalence of macrolide resistance phenotypes and its temporal trends and to evaluate the correlation with T and emm-types.…”

mentioning

confidence: 99%

Rapid Inversion of the Prevalences of Macrolide Resistance Phenotypes Paralleled by a Diversification of T and emm Types among Streptococcus pyogenes in Portugal

Silva-Costa¹,

Ramírez²,

Melo‐Cristino³

2005

In Portugal erythromycin resistance of 26.6% (n ‫؍‬ 352) remained constant during 1998 to 2003, however in 1998 the MLS B phenotype dominated (85%), whereas in 2003 the M phenotype prevailed (77%). A decline in T12/emm22 MLS B isolates could partially explain the drop in this phenotype, but the rise of the M phenotype was not due to clonal expansion.Although penicillin remains the antibiotic of choice in the treatment of Lancefield group A streptococci (GAS) infections, macrolides and lincosamides are recommended as suitable alternatives for patients allergic to penicillin (5). Newer macrolides, such as azithromycin, may be given once a day, making this an attractive option for the treatment of pharyngitis due to Streptococcus pyogenes. In Portugal, where penicillin V is not available, macrolides and lincosamides have the additional advantage of being a therapeutic option with an oral route of administration. High macrolide resistance in GAS was previously identified in Portugal (13) in line with other European countries (1, 4, 6) but in contrast to others (14,16). The aims of this study were to determine the prevalence of macrolide resistance phenotypes and its temporal trends and to evaluate the correlation with T and emm-types.A total of 1,321 GAS from clinical infections were collected from 30 laboratories, geographically distributed throughout Portugal, from January 1998 to December 2003. The isolates were distributed in the study period as follows: 153 in 1998, 240 in 1999, 213 in 2000, 216 in 2001, 270 in 2002, and 229 in 2003. The laboratories were asked to submit all nonduplicate GAS isolated from outpatients during the study period. Antimicrobial susceptibility testing, T-typing, and macrolide resistance phenotype and genotype were determined as previously described (7, 13). Strains were emm typed according to the recommendations of the Centers for Disease Control and Prevention (CDC) (http://www.cdc.gov/ncidod/biotech/strep/protocols .htm). The sequences of representatives of each restriction profile were searched against GenBank as well as the emm CDC database (http://www.cdc.gov/ncidod/biotech/strep /strepindex.htm). An isolate was considered to be of a given emm type if it had Ͼ95% identity over the 160 bases considered (3).Among this collection, 352 isolates (26.6%) were erythromycin resistant. Although there was a higher prevalence of resistant isolates recovered in 1998 (34.6%), the variation of the overall prevalence in the following years (19.6% in 1999, 27.7% in 2000, 25.5% in 2001, 23.7% in 2002, and 20.5% in 2003) was not significant ( 2 test, P ϭ 0.22) (Fig. 1). Only the 325 erythromycin-resistant isolates recovered from throat swabs associated with a diagnosis of pharyngitis were characterized further.Resistance to tetracycline was expressed by 38.7% (n ϭ 126) of the isolates (MIC 90 ϭ 96 g/ml, MIC range, 12 to 512 g/ml). The distribution of tetracycline-resistant isolates among the study years was as follows: 84.9% of the isolates recovered in 1998, 70.2% in 1999, 28.8% in 2000, 30.9...

“…Three vancomycin-resistant S. aureus (VRSA) strains carrying vanA have been reported in the literature (3,4,22), with an additional two strains reported in Michigan (J. T. Rudrick and D. M. Sievert, personal communications). Although S. pyogenes retains its original susceptibility to penicillin G, macrolide resistance is increasingly being encountered in this species (2,14,16).…”

mentioning

confidence: 99%

Activity of Retapamulin against Streptococcus pyogenes and Staphylococcus aureus Evaluated by Agar Dilution, Microdilution, E-Test, and Disk Diffusion Methodologies

Pankuch

Lin

Hoellman

et al. 2006

Self Cite

The in vitro activity of retapamulin against 106 Staphylococcus aureus isolates and 109 Streptococcus pyogenes isolates was evaluated by the agar dilution, broth microdilution, E-test, and disk diffusion methodologies. Where possible, the tests were performed by using the CLSI methodology. The results of agar dilution, broth microdilution, and E-test (all with incubation in ambient air) for S. aureus yielded similar MICs, in the range of 0.03 to 0.25 g/ml. These values corresponded to zone diameters between 25 and 33 mm by the use of a 2-g retapamulin disk. Overall, 99% of the agar dilution results and 95% of E-test results for S. aureus were within ؎1 dilution of the microdilution results. For S. pyogenes, the MICs obtained by the agar and broth microdilution methods (both after incubation in ambient air) were in the range of 0.008 to 0.03 g/ml, and E-test MICs (with incubation in ambient air) were 0.016 to 0.06 g/ml. For S. pyogenes, 100% of the agar dilution MIC results were within ؎1 dilution of the broth microdilution results. E-test MICs (after incubation in ambient air) were within ؎1 and ؎2 dilutions of the broth microdilution results for 76% and 99% of the isolates, respectively. E-test MICs for S. pyogenes strains in CO 2 were up to 4 dilutions higher than those in ambient air. Therefore, it is recommended that when retapamulin MICs are determined by E-test, incubation be done in ambient air and not in CO 2 , due to the adverse effect of CO 2 on the activity of this compound. Diffusion zones (with incubation in CO 2 ) for S. pyogenes were 18 to 24 mm. Retapamulin MICs for all strains by all methods (with incubation in ambient air) were <0.25 g/ml. These results demonstrate that S. pyogenes (including macrolide-resistant strains) and S. aureus (including methicillin-resistant and vancomycin-nonsusceptible strains) are inhibited by very low concentrations of retapamulin and that all four testing methods are satisfactory for use for susceptibility testing.