Efficacy of enrofloxacin against transmissible resistance gene (qnrS and aac (6’)-Ib-cr) - containing Escherichia coli isolates and clones

Öz

Aim of this study was to investigate the effects of qnrS1 and aac (6’)-Ib-cr on susceptibility, some pharmacodynamics of enrofloxacin against molecularly constructed and natural isolates of E. coli from animals. The MPCs and mutation frequencies of the drug were determined using the agar dilution method. Time-kill assays were used to determine the antimicrobial activity of the drug against E. coli strains. MPCs of enrofloxacin for qnrS1- and aac(6´)-Ib-cr-containing transformants increased from 0.128 µg/ml to 2 and 4 µg/ml. MPC:MIC ratio of enrofloxacin for transformants and E. coli isolates were 4 and 8, respectively. Mutation frequencies were markedly higher for transformants and isolates compared to control strain. Mutation frequencies diminished up to 6.2x10^-18 by increasing the concentrations used in the assay. The results of this study showed that enrofloxacin is less active against E. coli strains in case of additional mutations in QRDR. The concentration-dependent bactericidal effect of enrofloxacin is only observable by the eight times the MIC and increasing concentrations did not alter the bactericidal activity. The combination therapy can be considered to fight with resistant E. coli instead of monotherapy and artificially constructed E. coli strains, which exhibit similar reactions against ENR with natural E. coli isolates, can be used to test the pharmacological efficacy of the combinations.

Anahtar Kelimeler

• : E. coli,qnrS,aac(6´)-Ib-cr,mutant prevention concentration

Efficacy of enrofloxacin against transmissible resistance gene (qnrS and aac (6’)-Ib-cr) - containing Escherichia coli isolates and clones

Öz

Aim of this study was to investigate the effects of qnrS1 and aac (6’)-Ib-cr on susceptibility, some pharmacodynamics of enrofloxacin against molecularly constructed and natural isolates of E. coli from animals. The MPCs and mutation frequencies of the drug were determined using the agar dilution method. Time-kill assays were used to determine the antimicrobial activity of the drug against E. coli strains. MPCs of enrofloxacin for qnrS1- and aac(6´)-Ib-cr-containing transformants increased from 0.128 µg/ml to 2 and 4 µg/ml. MPC:MIC ratio of enrofloxacin for transformants and E. coli isolates were 4 and 8, respectively. Mutation frequencies were markedly higher for transformants and isolates compared to control strain. Mutation frequencies diminished up to 6.2x10^-18 by increasing the concentrations used in the assay. The results of this study showed that enrofloxacin is less active against E. coli strains in case of additional mutations in QRDR. The concentration-dependent bactericidal effect of enrofloxacin is only observable by the eight times the MIC and increasing concentrations did not alter the bactericidal activity. The combination therapy can be considered to fight with resistant E. coli instead of monotherapy and artificially constructed E. coli strains, which exhibit similar reactions against ENR with natural E. coli isolates, can be used to test the pharmacological efficacy of the combinations.

Kaynakça

1. European Medicines Agency (EMA) Committee for Veterinary Medicinal Products. Enrofloxacin (modifications for bovine, porcine and poultry) Summary Report (2), EMEA/MRL/388/98a, 1998a.
2. European Medicines Agency (EMA) Committee for Veterinary Medicinal Products. Enrofloxacin (extension to sheep, rabbits and lactating cows) Summary Report (3), EMEA/MRL/389/98b, 1998b.
3. Ferreira S, Toleman M, Ramalheira E, Da Silva GJ, Walsh T, Mendo S. First description of Klebsiella pneumoniae clinical isolates carrying both qnrA and qnrB genes in Portugal. Int J Antimicrob Agents, 35:584-586, 2010.
4. Fortini D, Fashae K, Garcia-Fernandez A, Villa L, Carattoli A. Plasmid-mediated quinolone resistance and β-lactamases in Escherichia coli from healthy animals from Nigeria. J Antimicrob Chemother, 66:1269-1272, 2011.
5. Jacobsen L, Cattoir V, Jensen KS, Hammerum AM, Nordman P, Frimondt-Moller N. Impact of low-level fluoroquinolone resistance genes qnrA1, qnrB19 and qnrS1 on ciprofloxacin treatment of isogenic Escherichia coli strains in a murine urinary track infection model. J Antimicrob Chemother, 67:2438-2444, 2012.
6. Kim MJ, Yun HJ, Kang JW, Kim S, Kwak JH, Choi EC. In vitro development of resistance to a novel fluoroquinolone, DW286, in methicillin-resistant Staphylococcus aureus clinical isolates. J Antimicrob Chemother, 51:1011-1016, 2003.
7. Martinez-Martinez L, Pascual A, Jacoby G. Quinolone resistance from a transferable plasmid. Lancet, 351:797-799, 1998.
8. Oloffson SK, Marcusson LL, Stormback A, Hughes D, Cars O. Dose-related selection of fluoroquinolone-resistant Escherichia coli. J Antimicrob Chemother, 60:795-801, 2007.

9. Ozawa M, Asai T. Relationships between mutant prevention concentrations and mutation frequencies against enrofloxacin for avian pathogenic Escherichia coli isolates. J Vet Med Sci, 75(6):709-713, 2013.
10. Randall LP, Cooles SW, Piddock LJV, Woodward MJ. Mutant prevention concentrations of ciprofloxacin and enrofloxacin for Salmonella enterica. J Antimicrob Chemother, 54:688-691, 2004.
11. Akiyama T, Khan AA. Molecular characterization of strains of fluoroquinolone resistant Salmonella entericaserovar Schwarzengrund carrying multidrug resistance isolated from imported foods. J Antimicrob Chemother, 67:101-110, 2012.
12. Ricci V, Tzakas P, Buckley A, Piddock LJ. Ciprofloxacin-resistant Salmonella enterica serovar Typhimurium strains are difficult to select in the absence of AcrB and TolC. Antimicrob Agents Chemother, 50(1):38-42, 2006.
13. Robicsek A, Jacoby GA, Hooper DC. The worldwide emergence of plasmid-mediated quinolone resistance. Lancet Infect Dis, 6:629-640, 2006.
14. Sahinturk P, Arslan E, Buyukcangaz E, Sonal S, Sen A, Ersoy F, Piddock LJV, Webber M, Cengiz M. High level fluoroquinolone resistance in Escherichia coli isolated from animals in Turkey is due to multiple mechanisms. Turk J Vet Anim Sci, 40:214-218, 2016.
15. Strahilevitz J, Jacoby GA, Hooper DC, Robicsek A. Plasmid-mediated quinolone resistance: a multifaceted threat. Clin Microbiol Rev, 22(4):664-689, 2009.
16. Sukul P, Spiteller M. Fluoroquinolone antibiotics in the environment. Rev Environ Contam Toxicol, 191:131-162, 2007.
17. Wang M, Sham DF, Jacoby GA, Hooper DC. Emerging plasmid-mediated quinolone resistance associated with the qnr gene in Klebsiella pneumoniae clinical isolates in the United States. Antimicrob Agents Chemother, 48(4):295-1299, 2004.
18. Wang M, Tran JH, Jacoby GA, Zhang Y, Wang F, Hooper DC. Plasmid-mediated quinolone resistance in clinical isolates of Escherichia coli from Shanghai, China. Antimicrob Agents Chemother, 47(7):2242-2248, 2003.
19. Wetzein HG. Comparative mutant prevention concentrations of pradofloxacin and other veterinary fluoroquinolones indicate differing potentials in preventing selection of resistance. Antimicrob Agents Chemother, 49(10):4166-41, 2005.
20. Begic D, Von Eiff C, Tsuji BT. Daptomycin pharmacodynamics against Staphylococcus aureus hemB mutants displaying the small colony variant phenotype. J Antimicrob Chemother, 63:977-981, 2009.
21. Blondeau JM. New concepts in antimicrobial susceptibility testing: the mutant prevention concentration and mutant selection window approach. Vet Dermatol, 20:383-396, 2009.
22. Briales A, Rodriguez-Martinez JM, Velasco C, Diaz De Alba P, Dominquez-Herrera J, Pachon J, Pascual A. In vitro effect of qnrA1, qnrB1, and qnrS1 genes on fluoroquinolone activity against isogenic Escherichia coli isolates with mutations gyrA and parC. Antimicrob Agents Chemother, 55:1266-1269, 2011.
23. Cengiz M, Sahinturk P, Sonal S, Buyukcangaz E, Sen A, Arslan E. In vitro bactericidal activity of enrofloxacin against gyrA mutant and qnr-containing Escherichia coli isolates from animals. Vet Rec, 172(18):474, 2013.
24. Chodhury G, Pazhani GP, Nair GB, Ghosh A, Rammurthy T. Transferable plasmid-mediated quinolone resistance in association with extended spectrum β-lactamases and fluoroquinolone-acetylating aminoglycoside-6-N acetyltransferase in clinical isolates of Vibrio fluvialis. Int J Antimicrob Agents, 38:169-173, 2011.
25. Dalhoff A, Schimitz FJ. In vitro antibacterial activity and pharmacodynamics of new quinolones. Eur J Clin Microbiol Infect Dis, 22:203-221, 2003.
26. Drago L, Nicola L, Mattina R, De Vecchi E. In vitro selection of resistance in Escherichia coli and Klebsiellaspp. at in vivo fluoroquinolone concentrations. BMC Microbiol, 10:119, 2010.
27. Emrich NC, Heisig A, Stubbings W, Labischinski H, Heisig P. Antibacterial activity of finafloxacin under different pH conditions against isogenic strains of Escherichia coli expressing combinations of defined mechanisms of fluoroquinolone resistance. J Antimicrob Chemother, 65:2530-2533, 2010.