Publications by authors named "Tridia van der Laan"

Species belonging to the complex (MKC) are frequently isolated from humans and the environment and can cause serious diseases. The most common MKC infections are caused by the species (), leading to tuberculosis-like disease. However, a broad spectrum of virulence, antimicrobial resistance and pathogenicity of these non-tuberculous mycobacteria (NTM) are observed across the MKC.

View Article and Find Full Text PDF

In the present manuscript, we describe how we successfully used ligand-based virtual screening (LBVS) to identify two small-molecule, drug-like hit classes with excellent ADMET profiles against the difficult to address microbial enzyme 1-deoxy-d-xylulose-5-phosphate synthase (DXPS). In the fight against antimicrobial resistance (AMR), it has become increasingly important to address novel targets such as DXPS, the first enzyme of the 2--methyl-d-erythritol-4-phosphate (MEP) pathway, which affords the universal isoprenoid precursors. This pathway is absent in humans but essential for pathogens such as , making it a rich source of drug targets for the development of novel anti-infectives.

View Article and Find Full Text PDF

Background: Drug-susceptibility testing (DST) of Mycobacterium tuberculosis complex (MTBC) isolates by the Mycobacteria Growth Indicator Tube (MGIT) approach is the most widely applied reference standard. However, the use of WGS is increasing in many developed countries to detect resistance and predict susceptibility. We investigated the reliability of WGS in predicting drug susceptibility, and analysed the discrepancies between WGS and MGIT against the first-line drugs rifampicin, isoniazid, ethambutol and pyrazinamide.

View Article and Find Full Text PDF

Pharmacodynamics are especially important in the treatment of multidrug- and extensively drug-resistant tuberculosis (M/XDR-TB). The free area under the concentration time curve in relation to MIC (AUC/MIC) is the most relevant pharmacokinetic (PK)-pharmacodynamic (PD) parameter for predicting the efficacy of levofloxacin (LFX). The objective of our study was to assess LFX PK variability in M/XDR-TB patients and its potential consequence for AUC/MIC ratios.

View Article and Find Full Text PDF

Introduction: Tuberculosis remains a global health problem and pharmacokinetic variability has been postulated as one of the causes of treatment failure and acquired drug resistance. New developments enable implementation of therapeutic drug monitoring, a strategy to evaluate drug exposure in order to tailor the dose to the individual patient, in tuberculosis treatment.

Areas Covered: Literature on pharmacokinetics and pharmacodynamics of anti-tuberculosis drugs was explored to evaluate the effect of drug exposure in relation to drug susceptibility, toxicity and efficacy.

View Article and Find Full Text PDF

Treatment of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) is becoming more challenging because of increased levels of drug resistance against second-line TB drugs. One promising group of antimicrobial drugs is carbapenems. Ertapenem is an attractive carbapenem for the treatment of MDR- and XDR-TB because its relatively long half-life enables once-daily dosing.

View Article and Find Full Text PDF

Mycobacterium species, including Mycobacterium tuberculosis and Mycobacterium leprae, are among the most potent human bacterial pathogens. The discovery of cytosolic mycobacteria challenged the paradigm that these pathogens exclusively localize within the phagosome of host cells. As yet the biological relevance of mycobacterial translocation to the cytosol remained unclear.

View Article and Find Full Text PDF

Pyrazinamide is important in the treatment of tuberculosis. Unfortunately, the diagnosis of pyrazinamide resistance is hampered by technical difficulties. We hypothesized that mutation analysis combined with the mycobacterial growth indicator tube (MGIT) phenotypic method would be a good predictor of pyrazinamide resistance.

View Article and Find Full Text PDF

Objectives: Fluoroquinolones are used in second-line treatment of tuberculosis (TB) and have a potential role in shortening TB treatment duration. The wide use of fluoroquinolones in the treatment of other infections, including respiratory tract infections in patients with (undiagnosed) active TB, could result in fluoroquinolone-resistant Mycobacterium tuberculosis. We determined the rate of fluoroquinolone resistance in M.

View Article and Find Full Text PDF

The mycobacterium growth indicator tube (MGIT960) automated liquid medium testing method is becoming the international gold standard for second-line drug susceptibility testing of multidrug- and extensively drug-resistant Mycobacterium tuberculosis complex isolates. We performed a comparative study of the current gold standard in the Netherlands, the Middlebrook 7H10 agar dilution method, the MGIT960 system, and the GenoType MTBDRsl genotypic method for rapid screening of aminoglycoside and fluoroquinolone resistance. We selected 28 clinical multidrug- and extensively drug-resistant M.

View Article and Find Full Text PDF

In this study, 2275 clinical isolates of 49 species of non-tuberculous mycobacteria isolated in The Netherlands were subjected to standardised drug susceptibility testing using the Middlebrook 7H10 agar dilution method. Clarithromycin and rifabutin were most active, with 87% and 83% of all isolates, respectively, being susceptible. Susceptibility to ciprofloxacin (44%) and amikacin (32%) was limited and was mostly restricted to Mycobacterium kansasii, Mycobacterium xenopi, Mycobacterium fortuitum and phylogenetically related species.

View Article and Find Full Text PDF

Accurate drug susceptibility testing (DST) for Mycobacterium tuberculosis is highly important for both therapy guidance and surveillance of drug resistance. Although liquid medium DST methods are used increasingly and seem most efficient and fast, the high costs hamper widespread implementation. In addition, an inability to check the colony morphology of the growing bacteria is a disadvantage of these methods.

View Article and Find Full Text PDF

Various new tuberculosis (TB) vaccine candidates in combination with new delivery systems, including subunit vaccines, are currently being evaluated by a number of laboratories. One vaccine candidate that has shown promising protective capacity in mice and guinea pigs is a fusion of Ag85B and ESAT-6. In this study, we have investigated the efficacy of this Ag85B-ESAT-6 fusion protein vaccine in a non-human primate model for TB.

View Article and Find Full Text PDF

In general non-human primates are highly susceptible to infections with Mycobacterium tuberculosis which therefore presents an explosive health threat to colonies. To screen for M. tuberculosis infections in non-human primates, the skin test is routinely used.

View Article and Find Full Text PDF

In an attempt to clarify the taxonomy of the Mycobacterium avium complex, the relationship between IS1245 RFLP, growth temperature, 16S rDNA signature sequences and the 16S-23S rDNA internally transcribed spacer (ITS) of 160 M. avium-complex isolates from different sources was investigated. All 70 isolates identified as M.

View Article and Find Full Text PDF