Micellar Electrokinetic Chromatography of Aminoglycosides.

The components of the aminoglycosides, e.g., gentamicin, sisomicin, netilmicin, kanamycin, amikacin, and tobramycin, and related impurities of these antibiotics can be separated by means of micellar electrokinetic chromatography (MEKC). Derivatization with o-phthaldialdehyde and thioglycolic acid is found to be appropriate for these antibiotics. The background electrolyte was composed of sodium tetraborate (100 mM), sodium deoxycholate (20 mM), and ß-cyclodextrin (15 mM) having a pH value of 10.0. This method is valid for evaluation of gentamicin, kanamycin, and tobramycin. It has to be adopted for amikacin, paromomycin, neomycin, and netilmicin.

Effect of sub-minimum inhibitory concentrations of ciprofloxacin, amikacin and colistin on biofilm formation and virulence factors of Escherichia coli planktonic and biofilm forms isolated from human urine

The aim of this study was to determine the effect of subinhibitory concentrations (sub-MICs) of ciprofloxacin, amikacin and colistin on biofilm formation, motility, curli fimbriae formation by planktonic and biofilm cells of E. coli strains isolated from the urine of patients with various urinary system infections. Quantification of biofilm formation was carried out using a microtiter plate assay and a spectrophotometric method. Bacterial enumeration was used to assess the viability of bacteria in the biofilm. Curli expression was determined by using YESCA agar supplemented with congo red. Using motility agar the ability to move was examined. All the antibiotics used at sub-MICs reduced biofilm formation in vitro, decreased the survival of bacteria, but had no effect on the motility of planktonic as well as biofilm cells. The inhibitory effect of sub-MICs of antimicrobial agents on curli fimbriae formation was dependent on the form in which the bacteria occurred, incubation time and antibiotic used. Our results clearly show that all the three antibiotics tested reduce biofilm production, interfere with curli expression but do not influence motility. This study suggests that ciprofloxacin, amikacin and colistin may be useful in the treatment of biofilm-associated infections caused by E. coli strains

Rapid and selective micellar electrokinetic chromatography for simultaneous determination of amikacin, kanamycin A, and tobramycin with UV detection and application in drug formulations.

A simple and selective micellar electrokinetic chromatography (MEKC) with UV detection is described for simultaneous determination of amikacin, tobramycin, and kanamycin A, performed in Tris buffer (180 mM; pH 9.1) with 300 mM sodium pentanesulfonate (SPS) as an anionic surfactant. Under this condition, good separation with high efficiency and the required short analysis time is achieved. The linear ranges of the method for the determination of amikacin, tobramycin, and kanamycin A were 0.1-0.5 mg / mL, 0.4-2.0 mg / mL, and 0.4-2.0 mg / mL, respectively; the detection limits (signal-to-noise ratio = 3; injection, 0.5 psi 5 s) were 0.08, 0.2, and 0.2 mg / mL, respectively. The small amount of sample required and the expeditiousness of the procedure allow content uniformity to be determined in individual commercial products.

Estudio comparativo de la sensibilidad in vitro a aminoglucósidos / A comparative study of sensitivity in vitro of aminoglycoside

Se analizó la susceptibilidad in vitro de 6200 cepas bacterianas de gérmenes gramnegativos, aislados de diversos procesos infecciosos en pacientes atendidos en dos Hospitales del Centro Médico ®La Raza¼, con una técnica automatizada y computarizada, hacia diversos antibióticos. Los antibióticos del grupo de los Aminoglucósidos mostraron una mayor actividad antibacteriana que la observada con otros grupos de antimicrobianos estudiados. Los Aminoglucósidos continúan representando una buena alternativa terapéutica particularmente contra los gérmenes gramnegativos adquiridos intrahospitalariamente

Improved procedure for extracting aminoglycosides from renal cortical tissue.

An efficient and reproducible procedure was developed for extracting aminoglycosides from renal cortical tissue. It involves a double homogenization and two rinsings with trichloroacetic acid. A higher recovery is obtained compared with that of other previously reported methods.

Determinación de la sensibilildad Bacteriana de Uropatogenos. Estudio comparativo de Aminocacina y Gentamicina / Bacterian sensibility determination of uropathogens. Comparative study of amicacin and gentamicin

Se han realizado un estudio comparativo de sensibilidad bacteriana entre amicacina y gentaminina, en 100 cepas de uropatógeos Gram negativos aislados de pacientes con infección urinaria recurrente, debido en algunos casos , a litiasis renal. La determinación de la sensibilidad se realizo por el método de Kirby Baves y de difusión en medio sólido incorporado, utilizandose las concentraciones de 30 mcg/ml y 10 mcg/ml de amicacina y gentamicina respectivamente. Se aislan 62 cepas de E. coli (62 por ciento), 18 cepas de proteus mirabilis (18 por ciento), 9 cepas de Klebsiella sp (9 por ciento), 8 cepas de entebacter sp (8 por ciento) y 3 cepas de Pseudomonas sp (3 por ciento). El mayor porcentaje de sensibilidad fue para Amicacina en comparación con gentamicina, llamando la atención el alto grado de resistencia observada con esta último antibiótico.