Immunoassay Analysis of Kanamycin in Serum Using the Tobramycin Kit

Abstract

bKanamycin is one of the aminoglycosides used in the treatment of multidrug-resistant tuberculosis. Blood concentrations of kanamycin are predictive for the treatment efficacy and the occurrence of side effects, and dose adjustments can be needed to optimize therapy. However, an immunoassay method for the quantification of kanamycin is not commercially available. We modified the existing tobramycin immunoassay to analyze kanamycin. This modified method was tested in a concentration range of 0.3 to 80.0 mg/liter for inaccuracy and imprecision. In addition, the analytical results of the immunoassay method were compared to those obtained by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method using Passing and Bablok regression. Within-day imprecision varied from 2.3 to 13.3%, and between-day imprecision ranged from 0.0 to 11.3%. The inaccuracy ranged from ؊5.2 to 7.6%. No significant cross-reactivity with other antimicrobials and antiviral agents was observed. The results of the modified immunoassay method were comparable with the LC-MS/MS analytical outcome. This new immunoassay method enables laboratories to perform therapeutic drug monitoring of kanamycin without the need for complex and expensive LC-MS/MS equipment.T uberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Unfortunately, resistance to the two firstline drugs in TB treatment, isoniazid and rifampin, is emerging (1). Treatment regimens for multidrug-resistant TB (MDR-TB) include a quinolone and an injectable: amikacin, kanamycin, or capreomycin (2). Unfortunately, the use of aminoglycosides comes with toxic effects, such as renal failure and irreversible hearing loss (3).Recently, a study with MDR-TB patients showed that the toxicity of aminoglycosides was correlated with the cumulative area under the curve (4). For efficacy, it is well recognized that the top serum concentration (C max ) is related to the efficacy of aminoglycosides (5). In addition, pharmacokinetic (PK) guided dosing reduced the daily dose of aminoglycosides, with excellent treatment outcome (6). This indicates that serum concentration monitoring may be of added value in the treatment of tuberculosis. The targeted peak concentration for kanamycin in MDR-TB is 20 to 30 mg/liter (7), while the trough concentration should be as low as reasonably achievable in order to prevent toxicity.Although analytical methods to quantify the serum or plasma concentrations of amikacin and kanamycin using liquid chromatography-tandem mass spectrometry (LC-MS/MS) (8-11) have been described, this technique is commonly not available in most developing countries (12). However, in contrast to the case for amikacin, no analytical immunoassay kit to analyze kanamycin is commercially available.Kanamycin is more structurally related to tobramycin than to amikacin (Fig. 1). The product insert of the tobramycin immunoassay kit, based on the enzyme multiplied immunoassay technique (EMIT), indicates cross-reactivity for kanamycin (13). We therefore explored the...

Determination and Identification of Antibiotic Drugs and Bacterial Strains in Biological Samples

“…Dijkstra and co-workers [45] also demonstrated the use of the tobramycin immunoassay kit for the detection of the kanamycin concentration in the serum. The results of the immunoassay method were compared with the LC-MS/MS analysis.…”

“…The results of the immunoassay method were compared with the LC-MS/MS analysis. This method is able to quantify a large range of kanamycin concentrations in a reliable and reproducible manner [45].…”

Personalized Medicine for Antibiotics: The Role of Nanobiosensors in Therapeutic Drug Monitoring

“…For an AB like colistin, pAb have been used for quantification, mainly in food [ 238 , 239 ]. In addition, tobramycin and kanamycin have been determined with a lower limit of quantification of 0.30 mg/L, verified in human plasma [ 240 ]. Due to the precision, selectivity, reliability, and low cost based on this technique there are several commercial kits and reagents on the market that allow the determination of some AB requiring TDM.…”

In Vitro Susceptibility of Mycobacterium tuberculosis to Amikacin, Kanamycin, and Capreomycin

“…More recently, it was noted that the chance of developing hearing loss is lower with reduced aminoglycoside dosing based on peak and trough levels (21). Therapeutic drug monitoring of aminoglycosides seems promising (10) and feasible, as bioanalytical immunoassays and mass spectrometric methods have been made available for amikacin and kanamycin (11,12). Obviously, to reach the same C max /MIC ratio for amikacin and kanamycin, which have different MIC values, a difference in dosing should be employed.…”