Evaluation of the contribution of gyrA mutation and efflux pumps to fluoroquinolone and multidrug resistance in pathogenic Escherichia coli isolates from dogs and cats

Abstract

ResumenSe estudió la disposición plasmática y urinaria de marbofloxacina en caninos (n = 6) tras la aplicación intramuscular de 2 mg/kg. En distintos tiempos posadministración se tomaron muestras de sangre hasta las 24 h, y de orina solo en los caninos machos (n = 4) a las 4, 8, 12 y 24 h. Se realizó una extracción líquido-líquido del analito con agua, metanol y centrifugado a 13.500 r. p. m. a 4 °C. La separación y cuantificación se realizó por HPLC mediante la elusión isocrática en fase reversa, utilizando columna C-18, detector de fluorescencia a 295 nm de excitación y 490 nm de emisión y fase móvil compuesta por agua, acetonitrilo y trietilamina. Las concentraciones plasmáticas temporales se analizaron con el software no compartimental PK Solution 2.0. Los resultados conseguidos indican pronta absorción, rápida y amplia distribución. El Cl y los valores conseguidos de t½β y TMR indican lenta depuración y prolongada permanencia. El ensayo determinó concentraciones plasmáticas perdurables hasta 24 h, y que exceden la CMI de patógenos relevantes. El cociente ABC/ CMI indica eficacia frente a microorganismos con CMI ≤ 0,15 μg/ml. Las concentraciones urinarias de marbofloxacina son más significativas que las plasmáticas. No obstante, se requieren nuevos estudios que avalen su empleo con la dosis y vía de aplicación ensayada.Palabras clave: caninos, farmacocinética, marbofloxacina, plasma, orina. Plasma and urine pharmacokinetics of intramuscular marbofloxacin in canines AbstractPlasma and urinary disposition of marbofloxacin was studied in canines (n = 6) after intramuscular administration of 2 mg/kg. At different times post-administration, blood samples were collected until 24 h, and urine samples, only from male dogs (n = 4) at 4; 8; 12, and 24 h. Liquid-liquid extraction of analyte with water, methanol, and centrifugation at 13500 rpm at 4 °C were performed. Separation and quantification were made using HPLC by reverse phase isocratic elution with a C18 column, fluorescence detector at 295 nm excitation and 490 nm emission, and a mobile phase consisting of water, acetonitrile, and triethylamine. Temporary plasma concentrations were analyzed with non-compartmental PK Solution 2.0 software.

Chromosomal and plasmid-mediated fluoroquinolone resistance mechanisms among broad-spectrum-cephalosporin-resistant Escherichia coli isolates recovered from companion animals in the USA

“…11 Previous studies have shown that the primary target of FQ in E. coli is DNA gyrase and mutations in the gyrase genes can lead to development of decreased susceptibility to FQs, thus complicating the treatment of infections. 4,5 Typically, a mutation in gyrA leading to the Ser-83 Leu substitution is the first gyrA mutation observed, which leads to a reduction in susceptibility; however, high-level FQ resistance (ciprofloxacin MIC . 4 mg/L) requires an additional mutation in gyrA at position 87 and at least one parC mutation at either position 80 or 84.…”

“…Treatment can be further complicated when FQ-resistant E. coli isolates exhibit multidrug resistance phenotypes. 2,4 Resistance to quinolones is primarily attributed to chromosomal mutations in DNA gyrase and/or topoisomerase IV genes or mutations in the regulatory genes of the acrAB efflux pump. 5,6 Changes in cell membrane permeability and overexpression of the multidrug efflux pump are complementary mechanisms that contribute to high-level FQ resistance in clinical isolates.…”

“…5,6 Changes in cell membrane permeability and overexpression of the multidrug efflux pump are complementary mechanisms that contribute to high-level FQ resistance in clinical isolates. 4,5,7 In addition, plasmid-mediated quinolone resistance (PMQR) genes, such as the target protection PMQR gene qnr, the enzymatic modification gene aac(6 ′ )-Ib-cr and the efflux pump gene qepA, have also been shown to reduce the susceptibility to quinolones. 6 Several epidemiological surveys have been conducted to identify the presence of PMQR in E. coli strains from humans and food animals.…”

Using next-generation sequencing to analyze Helicobacter pylori clones with different levofloxacin resistances from a patient with eradication failure

“…In E coli isolates, the inhibition of the efflux pump gene expression decreased the MIC of fluoroquinolone. [ 38 ] Furthermore, in this study, there were significantly more SNVs of Hp0970 (hefE) and Hp1329 (hefI) in the lower-level LVX-resistant clone than those in the higher-level LVX-resistant clones. In other words, a large number of SNVs may increase the risk of gene inactivation or activation.…”

Farmacocinética plasmática y urinaria de marbofloxacina intramuscular en caninos

“…Estas concentraciones muy superiores establecidas en experiencias realizadas con idénticas dosis por aplicación oral (16) serían suficientes para el tratamiento de infecciones urinarias no complicadas, por cuanto el éxito terapéutico depende de la dosis, el intervalo de aplicación, las concentraciones conseguidas (al menos cuatro veces la CMI), y que los microorganismos patógenos sean moderadamente susceptibles (26). Sin embargo, estos resultados son insuficientes para recomendar su aplicación a la dosis y por la vía ensayada, considerando la elevada manifestación de resistencia exhibida frente a las fluoroquinolonas (7,27), posiblemente por los valores de pH entre 5,5 y 7 dieta dependiente, de la orina de caninos (28), siendo menos eficaces las fluoroquinolonas en medio ácido (17,29,30). Por otro lado, la orina puede contener cantidades de magnesio, que reduce la actividad de las fluoroquinolonas, independientemente del pH (17,31).…”