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 Tetracycline Susceptibility Testing and Resistance Genes in Isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus Complex from a U.S. Military Hospital

2009 ◽  
Vol 53 (6) ◽  
pp. 2693-2695 ◽  
Author(s):  
Kevin S. Akers ◽  
Katrin Mende ◽  
Heather C. Yun ◽  
Duane R. Hospenthal ◽  
Miriam L. Beckius ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Susceptibility Testing ◽  
Tetracycline Resistance ◽  
Acinetobacter Calcoaceticus ◽  
Multidrug Resistant ◽  
Military Hospital ◽  
Tetracycline Resistance Genes ◽  
Testing Method

ABSTRACT Infections with multidrug-resistant Acinetobacter baumannii-Acinetobacter calcoaceticus complex bacteria complicate the care of U.S. military personnel and civilians worldwide. One hundred thirty-three isolates from 89 patients at our facility during 2006 and 2007 were tested by disk diffusion, Etest, and broth microdilution for susceptibility to tetracycline, doxycycline, minocycline, and tigecycline. Minocycline was the most active in vitro, with 90% of the isolates tested susceptible. Susceptibilities varied significantly with the testing method. The acquired tetracycline resistance genes tetA, tetB, and tetA(39) were present in the isolates.

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 Antimicrobial Use and Resistance in Swine Waste Treatment Systems

2006 ◽  
Vol 72 (12) ◽  
pp. 7813-7820 ◽  
Author(s):  
Archana Jindal ◽  
Svetlana Kocherginskaya ◽  
Asma Mehboob ◽  
Matthew Robert ◽  
Roderick I. Mackie ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Waste Treatment ◽  
Growth Promotion ◽  
Tetracycline Resistance ◽  
Land Application ◽  
Molecular Methods ◽  
23S Rrna ◽  
Organic Farm ◽  
Tetracycline Resistance Genes ◽  
Fecal Streptococci

ABSTRACT Chlortetracycline and the macrolide tylosin were identified as commonly used antimicrobials for growth promotion and prophylaxis in swine production. Resistance to these antimicrobials was measured throughout the waste treatment processes at five swine farms by culture-based and molecular methods. Conventional farm samples had the highest levels of resistance with both culture-based and molecular methods and had similar levels of resistance despite differences in antimicrobial usage. The levels of resistance in organic farm samples, where no antimicrobials were used, were very low by a culture-based method targeting fecal streptococci. However, when the same samples were analyzed with a molecular method detecting methylation of a specific nucleotide in the 23S rRNA that results in resistance to macrolides, lincosamides, and streptogramin B (MLSB), an unexpectedly high level of resistant rRNA (approximately 50%) was observed, suggesting that the fecal streptococci were not an appropriate target group to evaluate resistance in the overall microbial community and that background levels of MLSB resistance may be substantial. All of the feed samples tested, including those from the organic farm, contained tetracycline resistance genes. Generally, the same tetracycline resistance genes and frequency of detection were found in the manure and lagoon samples for each commercial farm. The levels of tetracycline and MLSB resistance remained high throughout the waste treatment systems, suggesting that the potential impact of land application of treated wastes and waste treatment by-products on environmental levels of resistance should be investigated further.

Abundances of Tetracycline Resistance Genes and Tetracycline Antibiotics during Anaerobic Digestion of Swine Waste

2019 ◽  
Vol 48 (1) ◽  
pp. 171-178 ◽  
Author(s):  
Melanie Couch ◽  
Getahun E. Agga ◽  
John Kasumba ◽  
Rohan R. Parekh ◽  
John H. Loughrin ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Resistance Genes ◽  
Tetracycline Resistance ◽  
Swine Waste ◽  
Tetracycline Antibiotics ◽  
Tetracycline Resistance Genes
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