SmaI typeability and tetracycline susceptibility/resistance in Streptococcus pyogenes isolates with efflux-mediated erythromycin resistance.
Anno: 2007
Rivista: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
Autori/autrici: Bacciaglia, Alessandro; Brenciani, Andrea; Varaldo, Pietro; Giovanetti, Eleonora
Lingua: ENG
Classificazione IRIS: 1.1 Articolo in rivista
Scheda completa IRIS: https://iris.univpm.it/handle/11566/50844
Citazioni:
SmaI typeability and tetracycline susceptibility/resistance in Streptococcus pyogenes isolates with efflux-mediated erythromycin resistance / Bacciaglia, A., Brenciani, A., Varaldo, P., Giovanetti, E.. - In: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY. - ISSN 0066-4804. - 51:(2007), pp. 3042-3043. [10.1128/AAC.00249-07]
Abstract:
These findings contribute to conclusively clarifying why, among S. pyogenes isolates with the M phenotype, the tetracycline- resistant ones are, as a rule, SmaI typeable, while the tetracycline-susceptible ones are not. Previous studies have shown that, while the two related genetic elements (Tn...1207.3 and 10394.4) typical of tetracycline-susceptible isolates are inserted into the same prophage, the tet(O)-mef(A) element typical of tetracycline-resistant isolates is inserted into a different prophage (6). The present results show that the R-M cassette encoding, in Tn1207.3-10394.4, the methyltransferase responsible for DNA resistance to cleavage by SmaI is absent in the tet(O)-mef(A) element where, together with an adjacent ORF, it is replaced by three new ORFs flanked, both upstream and downstream, by homologous regions.
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An Unexpressed tet(M) gene is present in the vast majority of tetracycline-susceptible streptococci carrying erm(B).
Anno: 2006
Autori/autrici: Montanari, M. P.; Giovanetti, Eleonora; Cochetti, I.; Brenciani, Andrea; Tili, E.; Baccaglia, A.; Vecchi, M.; Varaldo, P. E.
Lingua: ENG
Classificazione IRIS: 4.2 Abstract in Atti di convegno
Scheda completa IRIS: https://iris.univpm.it/handle/11566/82949
Citazioni:
An Unexpressed tet(M) gene is present in the vast majority of tetracycline-susceptible streptococci carrying erm(B) / Montanari, M.P., Giovanetti, E., Cochetti, I., Brenciani, A., Tili, E., Baccaglia, A., Vecchi, M., Varaldo, P.E.. - (2006), p. Abstract C2-1290.

Analisi della regione tet(O)-mef(A) in un elemento orf3-negativo di Streptococcus pyogenes.
Anno: 2005
Autori/autrici: Giovanetti, Eleonora; Brenciani, Andrea; Vecchi, M.; Menzo, Stefano; Varaldo, P. E.
Lingua: ITA
Classificazione IRIS: 4.3 Poster
Scheda completa IRIS: https://iris.univpm.it/handle/11566/82954
Citazioni:
Analisi della regione tet(O)-mef(A) in un elemento orf3-negativo di Streptococcus pyogenes / Giovanetti, E., Brenciani, A., Vecchi, M., Menzo, S., Varaldo, P.E.. - (2005).

Prophage association of mef(A) elements encoding efflux-mediated erythromycin resistance in Streptococcus pyogenes.
Anno: 2005
Rivista: JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
Autori/autrici: Giovanetti, Eleonora; Brenciani, Andrea; Vecchi, M; Manzin, A; Varaldo, Pietro
Lingua: ENG
Classificazione IRIS: 1.1 Articolo in rivista
Scheda completa IRIS: https://iris.univpm.it/handle/11566/51235
Citazioni:
Prophage association of mef(A) elements encoding efflux-mediated erythromycin resistance in Streptococcus pyogenes / Giovanetti, E., Brenciani, A., Vecchi, M., Manzin, A., Varaldo, P.. - In: JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY. - ISSN 0305-7453. - 55:(2005), pp. 445-451. [10.1093/jac/dki049]
Abstract:
OBJECTIVES: To compare different mef(A) elements of Streptococcus pyogenes for a possible chimeric genetic nature, i.e. a transposon inserted into a prophage. METHODS: Eleven S. pyogenes isolates with efflux-mediated erythromycin resistance were used. The isolates were typed using several... genotypic approaches. Gene detection was performed by PCR using specific primer pairs. The mef(A) elements of the test strains were induced with mitomycin C and phage DNA was extracted. Induction was monitored by PCR using primers targeting mef(A). RESULTS: Six tetracycline-susceptible isolates had PCR evidence of all of the eight open reading frames (ORFs) of the Tn1207.1 element; their mef(A) element was consistent with the Tn1207.3 element in four isolates and with the 58.8 kb chimeric element in two. Five tetracycline-resistant isolates had no PCR evidence of orf1 and orf2 and showed variable patterns as to orf3, orf7, and orf8. Three ORFs placed along the conserved region downstream of Tn1207.1 in the 58.8 kb mef(A) chimeric element were detected in the six tetracycline-susceptible, but not in the five tetracycline-resistant isolates. Induction assays with mitomycin C demonstrated that the mef(A) elements of all strains tested were present in culture supernatants in a DNAse-resistant form, such as a phage capsid. CONCLUSIONS: All recognized mef(A) elements of S. pyogenes appear to be prophage-associated. Whereas the two elements detected in tetracycline-susceptible isolates (Tn1207.3 and the 58.8 kb one) were apparently inserted into the same prophage, the tet(O)-mef(A) element was inserted into a different prophage. Phage transfer is likely to play a critical role in the dissemination of erythromycin resistance in S. pyogenes populations.
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Eritromicino-resistenza da efflusso in ceppi tetraciclino-sensibili (Tcs) e tetraciclino-resistenti (Tcr) di Streptococcus pyogenes.
Anno: 2004
Autori/autrici: Brenciani, Andrea; Kayode, K. O.; Monachetti, A.; Menzo, Stefano; Roberts, M. C.; Varaldo, P. E.; Giovanetti, Eleonora
Lingua: ITA
Classificazione IRIS: 4.3 Poster
Scheda completa IRIS: https://iris.univpm.it/handle/11566/82955
Citazioni:
Eritromicino-resistenza da efflusso in ceppi tetraciclino-sensibili (Tcs) e tetraciclino-resistenti (Tcr) di Streptococcus pyogenes / Brenciani, A., Kayode, K.O., Monachetti, A., Menzo, S., Roberts, M.C., Varaldo, P.E., Giovanetti, E.. - (2004).

Distribution and molecular analysis of mef(A)-containing elements in tetracycline-susceptible and -resistant Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance.
Anno: 2004
Rivista: JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
Autori/autrici: Brenciani, Andrea; OJO K. K., MONACHETTI A; Menzo, Stefano; Roberts, M. C.; Varaldo, Pietro; Giovanetti, Eleonora
Lingua: ENG
Classificazione IRIS: 1.1 Articolo in rivista
Scheda completa IRIS: https://iris.univpm.it/handle/11566/51133
Citazioni:
Distribution and molecular analysis of mef(A)-containing elements in tetracycline-susceptible and -resistant Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance / Brenciani, A., OJO K. K., M.A., Menzo, S., Roberts, M.C., Varaldo, P., Giovanetti, E.. - In: JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY. - ISSN 0305-7453. - 54:(2004), pp. 991-998. [10.1093/jac/dkh481]
Abstract:
OBJECTIVES: To analyse the distribution and molecular features of mef(A)-containing elements in a large collection of different Streptococcus pyogenes clinical isolates with efflux-mediated erythromycin resistance. To further characterize a tet(O)-mef(A) element. METHODS: Gene detection w...as carried out by PCR using primers designed from established sequences or from sequences in this study. From a tet(O)-mef(A) element (approximately 60 kb), an 11 972 bp region including the tet(O) and mef(A) genes was sequenced. RESULTS: In the tetracycline-susceptible isolates (n =28), the mef(A) gene was contained in a regular Tn1207.1 transposon (7.2 kb), which was inserted into one of two previously described elements, Tn1207.3 (approximately 52 kb) or a 58.8 kb chimeric element, both flanked by the comEC gene. In the tetracycline-resistant isolates (n =61), all of which carried the tet(O) gene, the mef(A) gene was part of a variable Tn1207.1-related transposon inserted into unique elements which contained the tet(O) gene approximately 2.3 to 5.5 kb upstream of the mef(A) gene and were not flanked by the comEC gene. In the Tn1207.1-like transposon of these tet(O)-mef(A) elements, only msr(D) (orf5) and a modified orf6, in addition to mef(A), were detected by PCR in all isolates tested; while orf1 and orf2 were always undetectable, orf3, orf7 and orf8 were found in variable percentages. In an orf3-positive element, sequencing identified four new open reading frames downstream of the tet(O) gene, followed by three short sequences with homology to sequences of the pneumococcal mega element. CONCLUSIONS: The mef(A) gene is carried on different chromosomal genetic elements depending on whether the isolates are susceptible or resistant to tetracycline.
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Presence of the tet(O) gene in erythromycin- and tetracycline-resistant strains of Streptococcus pyogenes and linkage with either the mef(A) or the erm(A) gene.
Anno: 2003
Rivista: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
Autori/autrici: Giovanetti, Eleonora; Brenciani, Andrea; Lupidi, R; Roberts, M. C.; Varaldo, Pietro
Classificazione IRIS: 1.1 Articolo in rivista
Scheda completa IRIS: https://iris.univpm.it/handle/11566/51171
Citazioni:
Presence of the tet(O) gene in erythromycin- and tetracycline-resistant strains of Streptococcus pyogenes and linkage with either the mef(A) or the erm(A) gene / Giovanetti, E., Brenciani, A., Lupidi, R., Roberts, M.C., Varaldo, P.. - In: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY. - ISSN 0066-4804. - 47:(2003), pp. 2844-2849.
Abstract:
Sep;(9):-9.

A novel efflux mechanism in Streptococcus pyogenes strains inducicbly resistant to erythromycin.
Anno: 2002
Autori/autrici: Giovanetti, Eleonora; Brenciani, Andrea; Burioni, R.; Montanari, M. P.; Varaldo, P. E.
Lingua: ENG
Classificazione IRIS: 4.2 Abstract in Atti di convegno
Scheda completa IRIS: https://iris.univpm.it/handle/11566/82947
Citazioni:
A novel efflux mechanism in Streptococcus pyogenes strains inducicbly resistant to erythromycin / Giovanetti, E., Brenciani, A., Burioni, R., Montanari, M.P., Varaldo, P.E.. - (2002).

Close association of erm(B) with tet(M) and erm(A) and mef(A) with tet(O) in erythromycin- and tetracycline-resistant isolates of Streptococcus pyogenes.
Anno: 2002
Autori/autrici: Giovanetti, Eleonora; Brenciani, Andrea; Lupidi, R.; Roberts, M. C.; Varaldo, P. E.
Lingua: ENG
Classificazione IRIS: 4.2 Abstract in Atti di convegno
Scheda completa IRIS: https://iris.univpm.it/handle/11566/82948
Citazioni:
Close association of erm(B) with tet(M) and erm(A) and mef(A) with tet(O) in erythromycin- and tetracycline-resistant isolates of Streptococcus pyogenes / Giovanetti, E., Brenciani, A., Lupidi, R., Roberts, M.C., Varaldo, P.E.. - (2002), p. Abstract n. 472.

A novel efflux system in inducibly erythromycin-resistant strains of Streptococcus pyogenes
Anno: 2002
Rivista: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
Autori/autrici: Giovanetti, Eleonora; Brenciani, Andrea; Burioni, R; Varaldo, Pietro
Lingua: ENG
Classificazione IRIS: 1.1 Articolo in rivista
Scheda completa IRIS: https://iris.univpm.it/handle/11566/52181
Citazioni:
A novel efflux system in inducibly erythromycin-resistant strains of Streptococcus pyogenes / Giovanetti, E., Brenciani, A., Burioni, R., Varaldo, P.. - In: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY. - ISSN 0066-4804. - 46:(2002), pp. 3750-3755.

Conjugative transfer of the erm(A) gene from erythromycin-resistant Streptococcus pyogenes to macrolide-susceptible S. pyogenes, Enterococcus faecalis and Listeria innocua
Anno: 2002
Rivista: JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
Autori/autrici: Giovanetti, Eleonora; Magi, G.; Brenciani, Andrea; Spinaci, C.; Lupidi, R.; Facinelli, Bruna; Varaldo, Pietro
Classificazione IRIS: 1.1 Articolo in rivista
Scheda completa IRIS: https://iris.univpm.it/handle/11566/50260
Citazioni:
Conjugative transfer of the erm(A) gene from erythromycin-resistant Streptococcus pyogenes to macrolide-susceptible S. pyogenes, Enterococcus faecalis and Listeria innocua / Giovanetti, E., Magi, G., Brenciani, A., Spinaci, C., Lupidi, R., Facinelli, B., Varaldo, P.. - In: JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY. - ISSN 0305-7453. - 50:(2002), pp. 249-252.