scholarly journals Genetic Elements Carrying erm(B) in Streptococcus pyogenes and Association with tet(M) Tetracycline Resistance Gene

2007 ◽  
Vol 51 (4) ◽  
pp. 1209-1216 ◽  
Author(s):  
Andrea Brenciani ◽  
Alessandro Bacciaglia ◽  
Manuela Vecchi ◽  
Luca A. Vitali ◽  
Pietro E. Varaldo ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Tetracycline Resistance ◽  
Complete Sequence ◽  
M Gene ◽  
Genetic Elements ◽  
Conjugative Transposons ◽  
Dna Insertion ◽  
Methylase Gene ◽  
Genotypic Characteristics ◽  
M Sequences

ABSTRACT This study was directed at characterizing the genetic elements carrying the methylase gene erm(B), encoding ribosome modification-mediated resistance to macrolide, lincosamide, and streptogramin B (MLS) antibiotics, in Streptococcus pyogenes. In this species, erm(B) is responsible for MLS resistance in constitutively resistant isolates (cMLS phenotype) and in a subset (iMLS-A) of inducibly resistant isolates. A total of 125 erm(B)-positive strains were investigated, 81 iMLS-A (uniformly tetracycline susceptible) and 44 cMLS (29 tetracycline resistant and 15 tetracycline susceptible). Whereas all tetracycline-resistant isolates carried the tet(M) gene, tet(M) sequences were also detected in most tetracycline-susceptible isolates (81/81 iMLS-A and 7/15 cMLS). In 2 of the 8 tet(M)-negative cMLS isolates, erm(B) was carried by a plasmid-located Tn917-like transposon. erm(B)- and tet(M)-positive isolates were tested by PCR for the presence of genes int (integrase), xis (excisase), and tndX (resolvase), associated with conjugative transposons of the Tn916 family. In mating experiments using representatives of different combinations of phenotypic and genotypic characteristics as donors, erm(B) and tet(M) were consistently cotransferred, suggesting their linkage in individual genetic elements. The linkage was confirmed by pulsed-field gel electrophoresis and hybridization studies, and different elements, variably associated with the different phenotypes/genotypes, were detected and characterized by amplification and sequencing experiments. A previously unreported genetic organization, observed in all iMLS-A and some cMLS isolates, featured an erm(B)-containing DNA insertion into the tet(M) gene of a defective Tn5397, a Tn916-related transposon. This new element was designated Tn1116. Genetic elements not previously described in S. pyogenes also included Tn6002, an unpublished transposon whose complete sequence is available in GenBank, and Tn3872, a composite element resulting from the insertion of the Tn917 transposon into Tn916 [associated with a tet(M) gene expressed in some cMLS isolates and silent in others]. The high frequency of association between a tetracycline-susceptible phenotype and tet(M) genes suggests that transposons of the Tn916 family, so far typically associated solely with a tetracycline-resistant phenotype, may be more widespread in S. pyogenes than currently believed.

scholarly journals 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

2003 ◽  
Vol 47 (9) ◽  
pp. 2844-2849 ◽  
Author(s):  
Eleonora Giovanetti ◽  
Andrea Brenciani ◽  
Remo Lupidi ◽  
Marilyn C. Roberts ◽  
Pietro E. Varaldo
Keyword(s):  
Streptococcus Pyogenes ◽  
Resistance Genes ◽  
Gel Electrophoresis ◽  
Tetracycline Resistance ◽  
Pulsed Field Gel Electrophoresis ◽  
M Gene ◽  
Pulsed Field ◽  
Conjugative Transposons ◽  
Tetracycline Resistance Genes ◽  
Resistant Strains

ABSTRACT Sixty-three recent Italian clinical isolates of Streptococcus pyogenes resistant to both erythromycin (MICs ≥ 1 μg/ml) and tetracycline (MICs ≥ 8 μg/ml) were genotyped for macrolide and tetracycline resistance genes. We found 19 isolates carrying the mef(A) and the tet(O) genes; 25 isolates carrying the erm(A) and tet(O) genes; and 2 isolates carrying the erm(A), tet(M), and tet(O) genes. The resistance of all erm(A)-containing isolates was inducible, but the isolates could be divided into two groups on the basis of erythromycin MICs of either >128 or 1 to 4 μg/ml. The remaining 17 isolates included 15 isolates carrying the erm(B) gene and 2 isolates carrying both the erm(B) and the mef(A) genes, with all 17 carrying the tet(M) gene. Of these, 12 carried Tn916-Tn1545-like conjugative transposons. Conjugal transfer experiments demonstrated that the tet(O) gene moved with and without the erm(A) gene and with the mef(A) gene. These studies, together with the results of pulsed-field gel electrophoresis experiments and hybridization assays with DNA probes specific for the tet(O), erm(A), and mef(A) genes, suggested a linkage of tet(O) with either erm(A) or mef(A) in erythromycin- and tetracycline-resistant S. pyogenes isolates. By amplification and sequencing experiments, we detected the tet(O) gene ca. 5.5 kb upstream from the mef(A) gene. This is the first report demonstrating the presence of the tet(O) gene in S. pyogenes and showing that it may be linked with another gene and can be moved by conjugation from one chromosome to another.

scholarly journals Clonal Diversity and Resistance Mechanisms in Tetracycline-Nonsusceptible Streptococcus pneumoniae Isolates in Poland

2007 ◽  
Vol 51 (4) ◽  
pp. 1155-1163 ◽  
Author(s):  
Radosław Izdebski ◽  
Ewa Sadowy ◽  
Janusz Fiett ◽  
Paweł Grzesiowski ◽  
Marek Gniadkowski ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Tetracycline Resistance ◽  
Clonal Diversity ◽  
Resistance Mechanisms ◽  
Pfge Type ◽  
Cross Resistance ◽  
M Gene ◽  
Conjugative Transposons ◽  
Tetracycline Resistance Genes ◽  
Resistance Determinants

ABSTRACT The frequency of tetracycline resistance in Streptococcus pneumoniae isolates in Poland is one of the highest in Europe. The aim of this study was to analyze the clonal diversity and resistance determinants of tetracycline-nonsusceptible S. pneumoniae isolates identified in Poland and to investigate the effect of tetracycline resistance on their susceptibilities to tigecycline, doxycycline, and minocycline. We have analyzed 866 pneumococcal isolates collected from 1998 to 2003 from patients with respiratory tract diseases, and 242 of these (27.9%) were found to be resistant to tetracycline. All of the resistant isolates were characterized by testing of their susceptibilities to other antimicrobials, serotyping, pulsed-field gel electrophoresis (PFGE), and identification of tetracycline resistance genes and transposons. Selected isolates representing the main PFGE types were analyzed by multilocus sequence typing. Among the isolates investigated, 27 serotypes and 146 various PFGE patterns, grouped into 90 types, were discerned. The most common PFGE type, corresponding to serotype 19F and sequence type 423, was represented by 22.3% of all of the tetracycline-resistant isolates. The tet(M) gene was the sole resistance gene in the group of isolates studied, and in over 96% of the isolates, the Tn916 family of tet(M)-containing conjugative transposons was detected. Several isolates contained specific variants of the transposons, the Tn1545-like, Tn3872-like, or Tn2009-like element. The correlation between the MICs of tetracycline, doxycycline, and minocycline was revealed, whereas no cross-resistance to tetracycline and tigecycline was observed.

scholarly journals Heterogeneity of Tn5253-Like Composite Elements in ClinicalStreptococcus pneumoniaeIsolates

2011 ◽  
Vol 55 (4) ◽  
pp. 1453-1459 ◽  
Author(s):  
Marina Mingoia ◽  
Emily Tili ◽  
Esther Manso ◽  
Pietro E. Varaldo ◽  
Maria Pia Montanari
Keyword(s):  
Tetracycline Resistance ◽  
Erythromycin Resistance ◽  
Integrase Gene ◽  
Chloramphenicol Resistance ◽  
Site Specific ◽  
Considerable Heterogeneity ◽  
Genetic Elements ◽  
Conjugative Transposons ◽  
Composite Element ◽  
Cell Genome

ABSTRACTSeveral drug resistances inStreptococcus pneumoniaeare associated with mobile genetic elements, which are loosely subdivided into a group of smaller (18- to 27-kb) and a group of larger (>50-kb) elements. While the elements of the former group, which typically carry the tetracycline resistance determinanttet(M) and whose prototype is Tn916(18 kb), have been studied extensively, the larger elements, whose prototype is Tn5253(∼65.5 kb), are not as well explored. Tn5253is a composite structure consisting of two independent conjugative transposons, Tn5251(which is virtually identical to Tn916) and Tn5252(∼47.5 kb), with the former inserted into the latter. Tn5252, which so far has only partially been sequenced, carries an integrase gene, driving its site-specific insertion into the host cell genome, and the chloramphenicol resistancecatpC194determinant. This study investigated 20 clinical isolates ofS. pneumoniae, which were selected on the basis ofcatpC194-mediated chloramphenicol resistance. All 20 isolates harbored a Tn5253-like element. The composite elements (some of which have been completely sequenced) demonstrated considerable heterogeneity that stemmed from a dual variability: in the Tn5252-like element, due primarily to differences in the integrase gene but also to differences in cargo genes and in the overall genetic organization, and in the Tn916-like element, with the possible involvement, besides Tn916, of a number of Tn916family pneumococcal elements carrying different erythromycin resistance genes. In mating experiments, only one composite element, containing a less typical Tn916family element, appeared to be nonmobile. Being part of a Tn5253-like composite element may confer on some Tn916-like transposons, which are apparently nontransferable as independent genetic elements, the ability to be mobilized.

scholarly journals Phenotypes and Genotypes of Erythromycin-ResistantStreptococcus pyogenes Strains in Italy and Heterogeneity of Inducibly Resistant Strains

1999 ◽  
Vol 43 (8) ◽  
pp. 1935-1940 ◽  
Author(s):  
Eleonora Giovanetti ◽  
Maria Pia Montanari ◽  
Marina Mingoia ◽  
Pietro Emanuele Varaldo
Keyword(s):  
Streptococcus Pyogenes ◽  
Tetracycline Resistance ◽  
Erythromycin Resistance ◽  
Testing Conditions ◽  
Resistant Strains ◽  
Methylase Gene ◽  
Set Up ◽  
Susceptibility Patterns ◽  
Disk Test ◽  
Level Resistance

ABSTRACT A total of 387 clinical strains of erythromycin-resistant (MIC, ≥1 μg/ml) Streptococcus pyogenes, all isolated in Italian laboratories from 1995 to 1998, were examined. By the erythromycin-clindamycin double-disk test, 203 (52.5%) strains were assigned to the recently described M phenotype, 120 (31.0%) were assigned to the inducible macrolide, lincosamide, and streptogramin B resistance (iMLS) phenotype, and 64 (16.5%) were assigned to the constitutive MLS resistance (cMLS) phenotype. The inducible character of the resistance of the iMLS strains was confirmed by comparing the clindamycin MICs determined under normal testing conditions and those determined after induction by pregrowth in 0.05 μg of erythromycin per ml. The MICs of erythromycin, clarithromycin, azithromycin, josamycin, spiramycin, and the ketolide HMR3004 were then determined and compared. Homogeneous susceptibility patterns were observed for the isolates of the cMLS phenotype (for all but one of the strains, HMR3004 MICs were 0.5 to 8 μg/ml and the MICs of the other drugs were >128 μg/ml) and those of the M phenotype (resistance only to the 14- and 15-membered macrolides was recorded, with MICs of 2 to 32 μg/ml). Conversely, heterogeneous susceptibility patterns were observed in the isolates of the iMLS phenotype, which were subdivided into three distinct subtypes designated iMLS-A, iMLS-B, and iMLS-C. The iMLS-A strains (n = 84) were highly resistant to the 14-, 15-, and 16-membered macrolides and demonstrated reduced susceptibility to low-level resistance to HMR3004. The iMLS-B strains (n = 12) were highly resistant to the 14- and 15-membered macrolides, susceptible to the 16-membered macrolides (but highly resistant to josamycin after induction), and susceptible to HMR3004 (but intermediate or resistant after induction). The iMLS-C strains (n = 24) had lower levels of resistance to the 14- and 15-membered macrolides (with erythromycin MICs increasing two to four times after induction), were susceptible to the 16-membered macrolides (but resistant to josamycin after induction), and remained susceptible to HMR3004, also after induction. The erythromycin resistance genes in 100 isolates of the different groups were investigated by PCR. All cMLS and iMLS-A isolates tested had theermAM (ermB) gene, whereas all iMLS-B and iMLS-C isolates had the ermTR gene (neither methylase gene was found in isolates of other groups). The M isolates had only the macrolide efflux (mefA) gene, which was also found in variable proportions of cMLS, iMLS-A, iMLS-B, and iMLS-C isolates. The three iMLS subtypes were easily differentiated by a triple-disk test set up by adding a josamycin disk to the erythromycin and clindamycin disks of the conventional double-disk test. Tetracycline resistance was not detected in any isolate of the iMLS-A subtype, whereas it was observed in over 90% of both iMLS-B and iMLS-C isolates.

scholarly journals Intra- and Interspecies Conjugal Transfer of Tn916-Like Elements from Lactococcus lactis In Vitro and In Vivo

2009 ◽  
Vol 75 (19) ◽  
pp. 6352-6360 ◽  
Author(s):  
Joanna Boguslawska ◽  
Joanna Zycka-Krzesinska ◽  
Andrea Wilcks ◽  
Jacek Bardowski
Keyword(s):  
Antibiotic Resistance ◽  
Lactococcus Lactis ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Raw Milk ◽  
M Gene ◽  
Transfer Resistance

ABSTRACT Tetracycline-resistant Lactococcus lactis strains originally isolated from Polish raw milk were analyzed for the ability to transfer their antibiotic resistance genes in vitro, using filter mating experiments, and in vivo, using germfree rats. Four of six analyzed L. lactis isolates were able to transfer tetracycline resistance determinants in vitro to L. lactis Bu2-60, at frequencies ranging from 10−5 to 10−7 transconjugants per recipient. Three of these four strains could also transfer resistance in vitro to Enterococcus faecalis JH2-2, whereas no transfer to Bacillus subtilis YBE01, Pseudomonas putida KT2442, Agrobacterium tumefaciens UBAPF2, or Escherichia coli JE2571 was observed. Rats were initially inoculated with the recipient E. faecalis strain JH2-2, and after a week, the L. lactis IBB477 and IBB487 donor strains were introduced. The first transconjugants were detected in fecal samples 3 days after introduction of the donors. A subtherapeutic concentration of tetracycline did not have any significant effect on the number of transconjugants, but transconjugants were observed earlier in animals dosed with this antibiotic. Molecular analysis of in vivo transconjugants containing the tet(M) gene showed that this gene was identical to tet(M) localized on the conjugative transposon Tn916. Primer-specific PCR confirmed that the Tn916 transposon was complete in all analyzed transconjugants and donors. This is the first study showing in vivo transfer of a Tn916-like antibiotic resistance transposon from L. lactis to E. faecalis. These data suggest that in certain cases food lactococci might be involved in the spread of antibiotic resistance genes to other lactic acid bacteria.

scholarly journals Diversity and Mobility of Integrative and Conjugative Elements in Bovine Isolates of Streptococcusagalactiae, S. dysgalactiae subsp. dysgalactiae, and S. uberis

2010 ◽  
Vol 76 (24) ◽  
pp. 7957-7965 ◽  
Author(s):  
Marisa Haenni ◽  
Estelle Saras ◽  
Stéphane Bertin ◽  
Pierre Leblond ◽  
Jean-Yves Madec ◽  
...  
Keyword(s):  
Horizontal Gene Transfer ◽  
Gel Electrophoresis ◽  
Tetracycline Resistance ◽  
Pulsed Field Gel Electrophoresis ◽  
Human Origin ◽  
M Gene ◽  
Integrative And Conjugative Elements ◽  
Lysine Trna ◽  
Resistant Strains ◽  
Related Element

ABSTRACT Bovine isolates of S treptococcus agalactiae (n = 76), S treptococcus dysgalactiae subsp. dysgalactiae (n = 32), and S treptococcus uberis (n = 101) were analyzed for the presence of different integrative and conjugative elements (ICEs) and their association with macrolide, lincosamide, and tetracycline resistance. The diversity of the isolates included in this study was demonstrated by multilocus sequence typing for S. agalactiae and pulsed-field gel electrophoresis for S. dysgalactiae and S. uberis. Most of the erythromycin-resistant strains carry an ermB gene. Five strains of S. uberis that are resistant to lincomycin but susceptible to erythromycin carry the lin(B) gene, and one has both linB and lnuD genes. In contrast to S. uberis, most of the S. agalactiae and S. dysgalactiae tetracycline-resistant isolates carry a tet(M) gene. A tet(S) gene was also detected in the three species. A Tn916-related element was detected in 30 to 50% of the tetracycline-resistant strains in the three species. Tetracycline resistance was successfully transferred by conjugation to an S. agalactiae strain. Most of the isolates carry an ICE integrated in the rplL gene. In addition, half of the S. agalactiae isolates have an ICE integrated in a tRNA lysine (tRNALys) gene. Such an element is also present in 20% of the isolates of S. dysgalactiae and S. uberis. A circular form of these ICEs was detected in all of the isolates tested, indicating that these genetic elements are mobile. These ICEs could thus also be a vehicle for horizontal gene transfer between streptococci of animal and/or human origin.

scholarly journals In Vitro Activities of Tigecycline against Erythromycin-Resistant Streptococcus pyogenes and Streptococcus agalactiae: Mechanisms of Macrolide and Tetracycline Resistance

2004 ◽  
Vol 48 (1) ◽  
pp. 323-325 ◽  
Author(s):  
C. Betriu ◽  
E. Culebras ◽  
I. Rodríguez-Avial ◽  
M. Gómez ◽  
B. A. Sánchez ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Resistance Genes ◽  
Streptococcus Agalactiae ◽  
Tetracycline Resistance ◽  
Tetracycline Resistance Genes

ABSTRACT The activity of tigecycline was tested against erythromycin-resistant streptococci (107 Streptococcus pyogenes and 98 Streptococcus agalactiae strains). The presence of erythromycin and tetracycline resistance genes was determined by PCR. Among S. pyogenes strains the most prevalent gene was mef(A) (91.6%). The erm(B) gene was the most prevalent (65.3%) among S. agalactiae strains. Tigecycline proved to be very active against all the isolates tested (MIC at which 90% of the isolates tested were inhibited, 0.06 μg/ml), including those resistant to tetracycline.

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

2005 ◽  
Vol 49 (12) ◽  
pp. 4999-5006 ◽  
Author(s):  
Ileana Cochetti ◽  
Manuela Vecchi ◽  
Marina Mingoia ◽  
Emily Tili ◽  
Maria R. Catania ◽  
...  
Keyword(s):  
Tetracycline Resistance ◽  
Sequence Type ◽  
Open Reading Frames ◽  
Resistant Isolate ◽  
Pfge Type ◽  
Polymorphism Analysis ◽  
Erythromycin Resistance ◽  
M Gene ◽  
Sequence Types

ABSTRACT 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 PCR-restriction fragment length polymorphism analysis. Twenty-eight of the 30 mef(A) isolates shared a pulsed-field gel electrophoresis (PFGE) type corresponding to the England14-9 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 tetracycline-resistant 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).

Sign in / Sign up

Export Citation Format

Share Document