MICs of 32 antimicrobial agents for Rhodococcus equi isolates of animal origin.
Abstract: The aim of this study was to determine the MICs of 32 antimicrobial agents for 200 isolates of Rhodococcus equi of animal origin by applying a recently described broth microdilution protocol, and to investigate isolates with distinctly elevated rifampicin MICs for the genetic basis of rifampicin resistance. Methods: The study included 200 R. equi isolates, including 160 isolates from horses and 40 isolates from other animal sources, from the USA and Europe. MIC testing of 32 antimicrobial agents or combinations thereof followed a recently published protocol. A novel PCR protocol for the joint amplification of the three rpoB regions in which rifampicin resistance-mediating mutations have been reported was applied to isolates with elevated rifampicin MICs. The amplicons were sequenced and screened for mutations. Results: Susceptibility testing revealed a rather uniform distribution of MICs for most of the antimicrobial agents tested. The lowest MICs were seen for clarithromycin, rifampicin and imipenem. Six isolates (3%) exhibited distinctly higher MICs of rifampicin than the remaining 194 isolates. In five of these six isolates, single bp exchanges, which resulted in the amino acid exchanges Gln513Leu, Asp516Val, His526Asp or Ser531Leu, were detected in the rifampicin resistance-determining region 1 of the rpoB gene, with Gln513Leu representing a novel substitution for R. equi. Conclusions: This study shows the MIC distribution of 32 antimicrobial agents for a large collection of R. equi isolates of animal origin from two continents. Isolates that exhibited distinctly elevated MICs of rifampicin were only rarely detected.
Publication Date: 2013-11-24 PubMed ID: 24275117DOI: 10.1093/jac/dkt460Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research aimed to identify the minimum inhibitory concentrations (MICs) of 32 antimicrobials for 200 strains of the Rhodococcus equi bacteria, specifically those of animal origin. It also investigated antibiotic-resistance in these strains, focusing on resistance to Rifampicin.
About the Study
- The study included 200 Rhodococcus equi (R. equi) bacteria isolates, of which 160 were from horses and the remaining 40 from other animal sources. These samples were collected from locations in the USA and Europe.
- The aim was to determine the minimum inhibitory concentrations (MICs) of 32 different antimicrobial agents toward these bacteria—an index that indicates how much of an antimicrobial agent is needed to inhibit the growth of the bacteria. This was achieved by using a broth microdilution process.
- Another objective was to explore any isolates that had extreme rifampicin MICs and to investigate the genetic reasons driving rifampicin resistance. For this, they used a novel PCR (polymerase chain reaction) protocol to amplify three rpoB regions—the regions known to have the mutations mediating rifampicin resistance. This yielded amplicons (section of DNA made via PCR), the sequences of which were analyzed for mutations.
Results
- The MIC testing offered a rather even distribution of MICs for many of the tested antimicrobial agents. The lowest MICs belonged to clarithromycin, rifampicin, and imipenem.
- Out of the 200 strains, six (or 3%) displayed noticeably higher MICs for rifampicin, suggesting potential rifampicin resistance. Five of these six strains carried single base pair changes in the rifampicin resistance-determining region 1 of the rpoB gene. These changes caused amino acid substitutions Gln513Leu, Asp516Val, His526Asp, or Ser531Leu, and the Gln513Leu substitution was novel for R. equi.
Conclusion
- The investigation demonstrated the MIC distribution of 32 antimicrobial agents for a large set of R. equi bacterial isolates of animal origin from two continents.
- Importantly, the occurrence of isolates with considerably raised rifampicin MICs was uncommon, suggesting rifampicin resistance is relatively rare amongst these strains.
Cite This Article
APA
Riesenberg A, Feßler AT, Erol E, Prenger-Berninghoff E, Stamm I, Böse R, Heusinger A, Klarmann D, Werckenthin C, Schwarz S.
(2013).
MICs of 32 antimicrobial agents for Rhodococcus equi isolates of animal origin.
J Antimicrob Chemother, 69(4), 1045-1049.
https://doi.org/10.1093/jac/dkt460 Publication
Researcher Affiliations
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany.
MeSH Terms
- Actinomycetales Infections / microbiology
- Actinomycetales Infections / veterinary
- Animals
- Anti-Infective Agents / pharmacology
- DNA-Directed RNA Polymerases / genetics
- Europe
- Microbial Sensitivity Tests
- Mutation, Missense
- Polymerase Chain Reaction
- Rhodococcus equi / drug effects
- Rhodococcus equi / genetics
- Rhodococcus equi / isolation & purification
- Sequence Analysis, DNA
- United States
Citations
This article has been cited 16 times.- Zúñiga MP, Badillo E, Abalos P, Valencia ED, Marín P, Escudero E, Galecio JS. Antimicrobial susceptibility of Rhodococcus equi strains isolated from foals in Chile.. World J Microbiol Biotechnol 2023 Jun 22;39(9):231.
- Lord J, Carter C, Smith J, Locke S, Phillips E, Odoi A. Antimicrobial resistance among Streptococcus equi subspecies zooepidemicus and Rhodococcus equi isolated from equine specimens submitted to a diagnostic laboratory in Kentucky, USA.. PeerJ 2022;10:e13682.
- Sting R, Schwabe I, Kieferle M, Münch M, Rau J. Fatal Infection in an Alpaca (Vicugna pacos) Caused by Pathogenic Rhodococcus equi.. Animals (Basel) 2022 May 19;12(10).
- Erol E, Scortti M, Fortner J, Patel M, Vázquez-Boland JA. Antimicrobial Resistance Spectrum Conferred by pRErm46 of Emerging Macrolide (Multidrug)-Resistant Rhodococcus equi.. J Clin Microbiol 2021 Sep 20;59(10):e0114921.
- Álvarez-Narváez S, Huber L, Giguère S, Hart KA, Berghaus RD, Sanchez S, Cohen ND. Epidemiology and Molecular Basis of Multidrug Resistance in Rhodococcus equi.. Microbiol Mol Biol Rev 2021 May 19;85(2).
- Rosa B. Equine Drug Transporters: A Mini-Review and Veterinary Perspective.. Pharmaceutics 2020 Nov 8;12(11).
- Mourenza Á, Gil JA, Mateos LM, Letek M. A Novel Screening Strategy Reveals ROS-Generating Antimicrobials That Act Synergistically against the Intracellular Veterinary Pathogen Rhodococcus equi.. Antioxidants (Basel) 2020 Jan 28;9(2).
- Chamroensakchai T, Manuprasert W, Leelahavanichkul A, Takkavatakarn K, Thongbor N, Jaroenpattrawut B, Kanjanabuch T. Rhodococcus induced false-positive galactomannan (GM), a biomarker of fungal presentation, in patients with peritoneal dialysis: case reports.. BMC Nephrol 2019 Dec 2;20(1):445.
- Álvarez-Narváez S, Giguère S, Anastasi E, Hearn J, Scortti M, Vázquez-Boland JA. Clonal Confinement of a Highly Mobile Resistance Element Driven by Combination Therapy in Rhodococcus equi.. mBio 2019 Oct 15;10(5).
- Willingham-Lane JM, Berghaus LJ, Berghaus RD, Hart KA, Giguère S. Effect of Macrolide and Rifampin Resistance on Fitness of Rhodococcus equi during Intramacrophage Replication and In Vivo.. Infect Immun 2019 Oct;87(10).
- Willingham-Lane JM, Berghaus LJ, Berghaus RD, Hart KA, Giguère S. Effect of Macrolide and Rifampin Resistance on the Fitness of Rhodococcus equi.. Appl Environ Microbiol 2019 Apr 1;85(7).
- Huber L, Giguère S, Slovis NM, Carter CN, Barr BS, Cohen ND, Elam J, Erol E, Locke SJ, Phillips ED, Smith JL. Emergence of Resistance to Macrolides and Rifampin in Clinical Isolates of Rhodococcus equi from Foals in Central Kentucky, 1995 to 2017.. Antimicrob Agents Chemother 2019 Jan;63(1).
- Rutenberg D, Venner M, Giguère S. Efficacy of Tulathromycin for the Treatment of Foals with Mild to Moderate Bronchopneumonia.. J Vet Intern Med 2017 May;31(3):901-906.
- Burton AJ, Giguère S, Berghaus LJ, Hondalus MK. Activity of clarithromycin or rifampin alone or in combination against experimental Rhodococcus equi infection in mice.. Antimicrob Agents Chemother 2015;59(6):3633-6.
- Berghaus LJ, Giguère S, Guldbech K, Warner E, Ugorji U, Berghaus RD. Comparison of Etest, disk diffusion, and broth macrodilution for in vitro susceptibility testing of Rhodococcus equi.. J Clin Microbiol 2015 Jan;53(1):314-8.
- de Carvalho CC, Costa SS, Fernandes P, Couto I, Viveiros M. Membrane transport systems and the biodegradation potential and pathogenicity of genus Rhodococcus.. Front Physiol 2014;5:133.
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