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 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 International Clone of Neisseriameningitidis Serogroup A with Tetracycline Resistance Due to tet(B)

2005 ◽  
Vol 49 (3) ◽  
pp. 1198-1200 ◽  
Author(s):  
Sharon A. Crawford ◽  
Kristin R. Fiebelkorn ◽  
Jan E. Patterson ◽  
James H. Jorgensen
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Gel Electrophoresis ◽  
Tetracycline Resistance ◽  
The United States ◽  
Pulsed Field Gel Electrophoresis ◽  
Clinical Isolates ◽  
Drug Efflux ◽  
Pulsed Field ◽  
Efflux Mechanism

ABSTRACT Thirteen Neisseria meningitidis clinical isolates from Africa, Asia, and the United States for which the tetracycline MICs were elevated (≥8 μg/ml) were examined for 14 recognized resistance genes. Only the drug efflux mechanism encoded by tet(B) was detected. All isolates were in serogroup A, belonged to complex ST-5, and were closely related by pulsed-field gel electrophoresis analysis.

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 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 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 Comparative Analysis of Sequences Flanking tet(W) Resistance Genes in Multiple Species of Gut Bacteria

2006 ◽  
Vol 50 (8) ◽  
pp. 2632-2639 ◽  
Author(s):  
Katarzyna A. Kazimierczak ◽  
Harry J. Flint ◽  
Karen P. Scott
Keyword(s):  
Resistance Genes ◽  
Bifidobacterium Longum ◽  
Tetracycline Resistance ◽  
Direct Repeats ◽  
Low Frequencies ◽  
Butyrivibrio Fibrisolvens ◽  
Reading Frame ◽  
Conjugative Transposons ◽  
Tetracycline Resistance Genes ◽  
Multiple Species

ABSTRACT tet(W) is one of the most abundant tetracycline resistance genes found in bacteria from the mammalian gut and was first identified in the rumen anaerobe Butyrivibrio fibrisolvens 1.230, where it is highly mobile and its transfer is associated with the transposable chromosomal element TnB1230. In order to compare the genetic basis for tet(W) carriage in different bacteria, we studied sequences flanking tet(W) in representatives of seven bacterial genera originating in diverse gut environments. The sequences 657 bp upstream and 43 bp downstream of tet(W) were 96 to 100% similar in all strains examined. A common open reading frame (ORF) was identified downstream of tet(W) in five different bacteria, while another conserved ORF that flanked tet(W) in B. fibrisolvens 1.230 was also present upstream of tet(W) in a human colonic Roseburia isolate and in another rumen B. fibrisolvens isolate. In one species, Bifidobacterium longum (strain F8), a novel transposase was located within the conserved 657-bp region upstream of tet(W) and was flanked by imperfect direct repeats. Additional direct repeats 6 bp long were identified on each end of a chromosomal ORF interrupted by the insertion of the putative transposase and the tet(W) gene. This tet(W) gene was transferable at low frequencies between Bifidobacterium strains. A putative minielement carrying a copy of tet(W) was identified in B. fibrisolvens transconjugants that had acquired the tet(W) gene on TnB1230. Several different mechanisms, including mechanisms involving plasmids and conjugative transposons, appear to be involved in the horizontal transfer of tet(W) genes, but small core regions that may function as minielements are conserved.

Characterization and Antimicrobial Resistance of Salmonella Typhimurium Isolates from Clinically Diseased Pigs in Korea

2016 ◽  
Vol 79 (11) ◽  
pp. 1884-1890 ◽  
Author(s):  
SANG-IK OH ◽  
JONG WAN KIM ◽  
MYEONGJU CHAE ◽  
JI-A JUNG ◽  
BYUNGJAE SO ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Salmonella Typhimurium ◽  
Resistance Genes ◽  
Gel Electrophoresis ◽  
Salmonella Enteritidis ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Pulsed Field Gel Electrophoresis ◽  
Pulsed Field ◽  
Antimicrobial Resistance Genes

ABSTRACT This study investigated the prevalence of Salmonella enterica serovar and antimicrobial resistance in Salmonella Typhimurium isolates from clinically diseased pigs collected from 2008 to 2014 in Korea. Isolates were also characterized according to the presence of antimicrobial resistance genes and pulsed-field gel electrophoresis patterns. Among 94 Salmonella isolates, 81 (86.2%) were identified as being of the Salmonella Typhimurium serotype, followed by Salmonella Derby (6 of 94, 6.4%), Salmonella 4,[5],12:i:− (4 of 94, 4.3%), Salmonella Enteritidis (2 of 94, 2.1%), and Salmonella Brandenburg (1 of 94, 1.1%). The majority of Salmonella Typhimurium isolates were resistant to tetracycline (92.6%), followed by streptomycin (88.9%) and ampicillin (80.2%). Overall, 96.3% of Salmonella Typhimurium isolates showed multidrug-resistant phenotypes and commonly harbored the resistance genes blaTEM (64.9%), flo (32.8%), aadA (55.3%), strA (58.5%), strB (58.5%), sulII (53.2%), and tetA (61.7%). The pulsed-field gel electrophoresis analysis of 45 Salmonella Typhimurium isolates from individual farms revealed 27 distinct patterns that formed one major and two minor clusters in the dendrogram analysis, suggesting that most of the isolates (91.1%) from diseased pigs were genetically related. These findings can assist veterinarians in the selection of appropriate antimicrobial agents to combat Salmonella Typhimurium infections in pigs. Furthermore, they highlight the importance of continuous surveillance of antimicrobial resistance and genetic status in Salmonella Typhimurium for the detection of emerging resistance trends.

Prevalence of tetracycline resistance genes and identification of tet(M) in clinical isolates of Escherichia coli from sick ducks in China

2013 ◽  
Vol 62 (6) ◽  
pp. 851-858 ◽  
Author(s):  
Gong-Zheng Hu ◽  
Yu-Shan Pan ◽  
Hua Wu ◽  
Han Hu ◽  
Rui Xu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Promoter Region ◽  
Tetracycline Resistance ◽  
Resistance Rate ◽  
Clinical Isolates ◽  
Animal Origin ◽  
Broth Microdilution ◽  
M Gene ◽  
Tetracycline Resistance Genes

Tetracycline resistance is one of the most frequently encountered resistance properties in bacteria of animal origin. The aim of the present study was to investigate the prevalence and diversity of tetracycline resistance (tet) genes among Escherichia coli clinical isolates from diseased ducks in China and to report the identification and sequencing of the tet(M) gene. The susceptibility of 85 Escherichia coli strains to tetracyclines was determined by broth microdilution, and the presence of tet genes was investigated by multiplex PCR. All of the 85 isolates were fully resistant to both oxytetracycline and tetracycline, and 76.5 % were resistant to doxycycline. Seventy-seven of the isolates (90.6 %) encoded multiple tet genes, with 17.6, 38.8 and 34.1 % encoding two, three and four tet genes, respectively, and only 7.1 % encoded a single tet(A) gene. The MICs of oxytetracycline and tetracycline for all isolates ranged from 16 to ≥128 µg ml−1 with a MIC90 of >128 µg ml−1, regardless of the type or number of tet genes encoded. Isolates containing tet(M) commonly had more than one tet gene per strain. The doxycycline resistance rate in the tet(M)-positive isolates was significantly higher than in the tet(M)-negative isolates (P<0.05). A full-length tet(M) gene, including the promoter region, was obtained by PCR in seven of the 41 tet(M)-positive isolates and was sequenced and cloned. The cloned tet(M) gene conferred resistance to tetracyclines in the recombinant Escherichia coli host strain. These results revealed that, in these isolates, the prevalence of multiple tet genes was strikingly high and that tet(M) played a role in doxycycline resistance.

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