Distribution and molecular analysis of mef(A)-containing elements in tetracycline-susceptible and -resistant Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance

Brenciani, Andrea; Ojo, Kayode K.; Monachetti, Alessia; Menzo, Stefano; Roberts, Marilyn C.; Varaldo, Pietro E.; Giovanetti, Eleonora

doi:10.1093/jac/dkh481

Cited by 54 publications

(47 citation statements)

References 25 publications

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“…The detection of the orf9 and orf56 genes of the 5Ј-and 3Ј-end regions of transposon Tn1207.3 in this mef(A)-containing strain indicated that Tn1207.1 was integrated into the conjugative transposon Tn1207.3. In addition, the detection of the tet(M) gene and not of tet(O) in this erythromycin-and tetracycline-resistant strain ruled out the carriage of Tn1207.1 into the recently described tet(O)-mef(A) element (7).…”

Section: Discussionmentioning

confidence: 64%

“…In S. pneumoniae, mega can be inserted at different sites in the chromosome or into a transposon Tn916-like genetic element, forming a new composite named Tn2009, which also contains the tetracycline resistance tet(M) gene (12,26). Tn1207.1 has been found in S. pneumoniae inserted within the competence celB gene (11,28), and in S. pyogenes, Tn1207.1 has been described as integrated into the conjugative transposon Tn1207.3 and into a conjugative tet(O)-mef(A) element (4,7,9,26).…”

Section: Streptococcus Agalactiae (Lancefield Group B Streptococcus)mentioning

confidence: 99%

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Erythromycin Resistance and Genetic Elements Carrying Macrolide Efflux Genes in Streptococcus agalactiae

Marimón

Valiente

Ercibengoa

et al. 2005

Antimicrob Agents Chemother

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The macrolide resistance determinants and genetic elements carrying the mef(A) and mef(E) subclasses of the mef gene were studied with Streptococcus agalactiae isolated in 2003 and 2004 from 7,084 vaginorectal cultures performed to detect carrier pregnant women. The prevalence of carriage was 18% (1,276 isolates), and that of erythromycin resistance 11.0% (129 of the 1,171 isolates studied). erm(B), erm(A) subclass erm(TR), and the mef gene, either subclass mef(A) or mef(E), were found in 72 (55.8%), 41 (31.8%), and 12 (9.3%) erythromycin-resistant isolates, while 4 isolates had more than 1 erythromycin resistance gene. Of the 13 M-phenotype mef-containing erythromycin-resistant S. agalactiae isolates, 11 had the mef(E) subclass gene alone, one had both the mef(E) and the erm(TR) subclass genes, and one had the mef(A) subclass gene. mef(E) subclass genes were associated with the carrying element mega in 10 of the 12 mef(E)-containing strains, while the single mef(A) subclass gene found was associated with the genetic element Tn1207.3. The nonconjugative nature of the mega element and the clonal diversity of mef(E)-containing strains determined by pulsed-field gel electrophoresis suggest that transformation is the main mechanism through which this resistance gene is acquired.

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Section: Discussionmentioning

confidence: 64%

Section: Streptococcus Agalactiae (Lancefield Group B Streptococcus)mentioning

confidence: 99%

Erythromycin Resistance and Genetic Elements Carrying Macrolide Efflux Genes in Streptococcus agalactiae

Marimón

Valiente

Ercibengoa

et al. 2005

Antimicrob Agents Chemother

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“…Y07780) (45) and of 98.5% with the same gene from S. pyogenes recently described in Italy (GenBank accession no. AJ715499) (4,14). No apparent linkage between mef(E) and tet(O) was detected in this strain in cross-PCR assays with primers specific for the two genes.…”

Section: Tet(l) Tet(m) and Tet(o)mentioning

confidence: 83%

“…The failure to find it in Europe had been attributed to the requirement for acquisition of the gene and the absence of selective pressure (18). However, the tet(O) gene has recently been found to be the customary tetracycline resistance determinant in the erythromycin-resistant S. pyogenes strains carrying gene mef(A) (4,14) or erm(A) (14).…”

Section: Tet(l) Tet(m) and Tet(o)mentioning

confidence: 99%

Molecular Characterization of Pneumococci with Efflux-Mediated Erythromycin Resistance and Identification of a Novel mef Gene Subclass, mef (I)

Cochetti

Vecchi

Mingoia

et al. 2005

Antimicrob Agents Chemother

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The molecular genetics of macrolide resistance were analyzed in 49 clinical pneumococci (including an "atypical" bile-insoluble strain currently assigned to the new species Streptococcus pseudopneumoniae) with efflux-mediated erythromycin resistance (M phenotype). All test strains had the mef gene, identified as mef(A) in 30 isolates and mef(E) in 19 isolates (including the S. pseudopneumoniae strain) on the basis of PCRrestriction fragment length polymorphism analysis. Twenty-eight of the 30 mef(A) isolates shared a pulsed-field gel electrophoresis (PFGE) type corresponding to the England 14 -9 clone. Of those isolates, 27 (20 belonging to serotype 14) yielded multilocus sequence type ST9, and one isolate yielded a new sequence type. The remaining two mef(A) isolates had different PFGE types and yielded an ST9 type and a new sequence type. Far greater heterogeneity was displayed by the 19 mef(E) isolates, which fell into 11 PFGE types, 12 serotypes (though not serotype 14), and 12 sequence types (including two new ones and an undetermined type for the S. pseudopneumoniae strain). In all mef(A) pneumococci, the mef element was a regular Tn1207.1 transposon, whereas of the mef(E) isolates, 17 carried the mega element and 2 exhibited a previously unreported organization, with no PCR evidence of the other open reading frames of mega. The mef gene of these two isolates, which did not match with the mef(E) gene of the mega element (93.6% homology) and which exhibited comparable homology (91.4%) to the mef(A) gene of the Tn1207.1 transposon, was identified as a novel mef gene variant and was designated mef(I). While penicillin-nonsusceptible isolates (three resistant isolates and one intermediate isolate) were all mef(E) strains, tetracycline resistance was also detected in three mef(A) isolates, due to the tet(M) gene carried by a Tn916-like transposon. A similar mechanism accounted for resistance in four of the five tetracyclineresistant isolates carrying mef(E), in three of which mega was inserted in the Tn916-like transposon, giving rise to the composite element Tn2009. In the fifth mef(E)-positive tetracycline-resistant isolate (the S. pseudopneumoniae strain), tetracycline resistance was due to the presence of the tet(O) gene, apparently unlinked to mef(E).

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“…Lately, a third chimeric element containing mefA and tetO, a tetracycline resistance gene, was described as having both conjugative-transposon and bacteriophage characteristics (21). These tetO-mefA chimeric elements are different from the other two elements, as they are composed of a varying number of genes similar to those of Tn1207.1 that have combined with a different set of bacteriophage genes, resulting in elements of various sizes (52 to 60 kb), which are integrated into chromosomal locations outside of the comEC gene (9,21,22).…”

mentioning

confidence: 99%

M.SpyI, a DNA Methyltransferase Encoded on a mefA Chimeric Element, Modifies the Genome of Streptococcus pyogenes

et al. 2007

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Distribution and molecular analysis of mef(A)-containing elements in tetracycline-susceptible and -resistant Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance

Abstract: The mef(A) gene is carried on different chromosomal genetic elements depending on whether the isolates are susceptible or resistant to tetracycline.

Cited by 54 publications

References 25 publications

Erythromycin Resistance and Genetic Elements Carrying Macrolide Efflux Genes in Streptococcus agalactiae

Erythromycin Resistance and Genetic Elements Carrying Macrolide Efflux Genes in Streptococcus agalactiae

Molecular Characterization of Pneumococci with Efflux-Mediated Erythromycin Resistance and Identification of a Novel mef Gene Subclass, mef (I)

M.SpyI, a DNA Methyltransferase Encoded on a mefA Chimeric Element, Modifies the Genome of Streptococcus pyogenes

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