Search

Background: Negative (vacuum) pressure therapy promotes wound healing. However, commercially available devices are unaffordable to most potential users in low- and middle-income countries (LMICs), limiting access to many patients who could benefit from this treatment. This study aimed to design and test a cheap and easy-to-build negative pressure device and provide its detailed open-source description, thereby enabling free replication. Methods: the negative pressure device was built using off-the-shelf materials available via e-commerce and was based on a small pump, a pressure transducer, and the simplest Arduino controller with a digital display (total retail cost ≤ 75 US$). The device allows the user to set any therapeutic range of intermittent negative pressure and has two independent safety mechanisms. The performance of the low-cost device was carefully tested on the bench using a phantom wound, producing a realistic exudate flow rate. Results: the device generates the pressure patterns set by the user (25–175 mmHg of vacuum pressure, 0–60 min periods) and can drain exudate flows within the clinical range (up to 1 L/h). Conclusions: a novel, low-cost, easy-to-build negative pressure device for wound healing displays excellent technical performance. The open-source hardware description provided here, which allows for free replication and use in LMICs, will facilitate the application and wider utilization of this therapy to patients.

Nontuberculous mycobacteria include 198 mycobacterial species. Among these, Mycobacteroides abscessus is a rapidly growing mycobacteria that causes lung and skin infections. M. abscessus lung infections are difficult to treat due to the high levels of resistance to several classes of antibiotics. The current treatment is based on combining at least two or three antibiotics. However, treatment outcomes remain very poor. The objective was to compare the in vitro activity of amikacin, tigecycline, imipenem, and clarithromycin, alone and in two different three-drug combinations (amikacin/tigecycline/imipenem and amikacin/tigecycline/clarithromycin) against seven M. abscessus subsp. abscessus clinical isolates using the time-kill assay. The two combinations showed greater activity than the antibiotics tested individually. Even though both combinations showed similar activity as well as no antagonistic activity, the combination including imipenem could not be an alternative treatment against M. abscessus subsp. abscessus lung infections caused by clarithromycin susceptible isolates. However, this combination could be considered against clarithromycin resistant isolates. Future studies are necessary to confirm this hypothesis This work was supported by the Ministerio de Economía y Competitividad, Instituto de Salud Carlos III, co-financed by the European Regional Development Fund (ERDF) ‘A way to achieve Europe’, the Spanish Ministry of Health (grant no. PI16/01047), Planes Nacionales de I+D+i 2008–2011/2013–2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía y Competitividad, Spanish Network for Research in Infectious Diseases (REIPI) (RD16/ 0016/0010) co‐financed by European Development Regional Fund (ERDF) “A way to achieve Europe” and operative program Intelligent Growth 2014–2020. This study was also supported by grant 2017SGR0809 from the Departament d’Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya and by a grant from Fundació La Marató de TV3 (grant no. 201816-10). EP-B received a grant from the Universitat de Barcelona (UB), Ajut de Personal Investigador en Formació (APIF-UB)

The main objective of this study was to compare in vitro activities of a novel fluoroquinolone (FQ), UB-8902, with ofloxacin (OFX), levofloxacin (LFX), and moxifloxacin (MOX) against Mycobacterium ...

The 2-(quinolin-4-yloxy)acetamides (QOAs) have been reported to be promising molecules for tuberculosis treatment. Recent studies demonstrated their potent antimycobacterial activity, biological stability and synergism with rifampicin. The identification of the molecular target is an essential step towards the development of a novel drug candidate. Here, we report the target identification of the QOAs. We found that these compounds are active against Mycobacterium tuberculosis clinical isolates resistant to isoniazid, rifampicin, ethambutol, streptomycin and ethionamide. The initial evidence that DNA gyrase might be the target of QOAs, based on high minimum inhibitory concentration (MIC) values against ofloxacin-resistant clinical isolates and structural similarities with fluoroquinolones, was discarded by experiments performed with M. tuberculosis GyrA point mutant, DNA gyrase supercoiling inhibition assay and overexpression of DNA gyrase. We selected spontaneous mutants for our lead compound 21 and observed that these strains were also resistant to all QOA derivatives. The genomes of the spontaneous mutants were sequenced, and the results revealed a single mutation in qcrB gene (T313A), which indicates that the QOAs target the cytochrome bc1 complex. The protein-compound interaction was further investigated by molecular docking. These findings reinforce the relevance of these compounds as promising candidates for the treatment of multidrug-resistant tuberculosis.

Rifampicin heteroresistance – where rifampicin-resistant and -susceptible tuberculosis (TB) bacilli co-exist – may result in failed standard TB treatment and potential spread of rifampicin-resistant strains. Detection of rifampicin heteroresistance in routine rapid diagnostic tests (RDTs) allows for patients to receive prompt and effective multidrug-resistant-TB treatment, and may improve rifampicin-resistant TB control.The limit of detection (LOD) of rifampicin heteroresistance for phenotypic drug susceptibility testing by the proportion method is 1%, yet is insufficiently documented for RDTs. We therefore aimed to determine, for the four RDTs (XpertMTB/RIF, XpertMTB/RIF Ultra, GenoTypeMTBDRplusv2.0, and GenoscholarNTM+MDRTBII), the LOD per probe and mutation, validated by colony-forming-unit-counting and targeted deep sequencing (Deeplex-MycTB).We selected one rifampicin-susceptible and four rifampicin-resistant strains, with mutation D435V, H445D, H445Y, and S450L respectively, mixed them in various proportions in triplicate, tested them with each RDT, and determined the LODs per mutation type. Deeplex-MycTB revealed concordant proportions of the minority resistant variants in the mixtures. The Deeplex-MycTB-validated-LODs ranged from 20-80% for XpertMTB/RIF, 20-70% for Xpert Ultra, 5-10% for GenoTypeMTBDRplusv2.0, and 1-10% for GenoscholarNTM+MTBII for the different mutations.Deeplex-MycTB, GenoTypeMTBDRplusv2.0, and GenoscholarNTM+MDRTBII, provide explicit information on rifampicin heteroresistance for the most frequently detected mutations. Classic Xpert and Ultra report rifampicin heteroresistance as rifampicin resistance, while Ultra may denote rifampicin heteroresistance through ‘mixed patterns’ of wild-type and mutant melt probe melt peak temperatures.Overall, our findings inform end-users that the threshold for reporting resistance in case of rifampicin heteroresistance is the highest for Classic Xpert and Ultra, to resolve phenotypic and genotypic discordant rifampicin-resistant TB results.

Tuberculosis (TB) remains a major threat to human health worldwide. The increasing incidence of non-tuberculous mycobacterial infections and particularly those produced by Mycobacterium avium has emphasized the need to develop new drugs. Additionally, high levels of natural drug resistance in non-tuberculous mycobacteria (NTM) and the emergence of multidrug-resistant (MDR) TB is of great concern. Antimicrobial peptides (AMPs) are antibiotics with broad-spectrum antimicrobial activity. The objective was to assess the activity of AMPs against Mycobacterium tuberculosis and M. avium clinical isolates. MICs were determined using microtitre plates and the resazurin assay. Mastoparan and melittin showed the greatest activity against M. tuberculosis, while indolicidin had the lowest MIC against M. avium. In conclusion, AMPs could be alternatives for the treatment of mycobacterial infections. Further investigation of AMPs' activity in combination and associated with conventional antibiotics and their loading into drug-delivery systems could lead to their use in clinical practice.

Purpose: To investigate bacillus Calmette–Guerin (BCG) infective capability and cytotoxicity in ARPE-19 cells.Methods: BCG inoculum was dispensed at a MOI 100:1 for 3 h in 90% confluent ARPE-19 cells. Infection rates at different time points were determined by colony forming units (CFU) count and, in parallel, by the number of microscopically infected cells. WST-1 reagent was used for cytotoxicity assays.Results: A 67-year-old man previously treated with intravesical BCG for bladder carcinoma presented with chronic, refractory, bilateral uveitis with macular edema. Quiescence was achieved only after commencing antituberculous treatment. BCG infection rate by two methods peaked at 48 h (16 ± 5.7% by CFU count and 40 ± 7.7% by microscopy; p = 0.058). BCG adhesion, phagocytosis, intracellular proliferation and cytolysis was observed. Cytotoxicity was minimal and did not differ from uninfected cells.Conclusions: BCG can infect at low rates and proliferate in ARPE-19 cells without toxicity in the surro...

Repurposing of drugs to treat tuberculosis (TB) has been considered an alternative to overcome the global TB epidemic, especially to combat drug-resistant forms of the disease. Mefloquine has been reported as a potent drug to kill drug-resistant strains of Mycobacterium tuberculosis. In addition, mefloquine-derived molecules have been synthesised and their effectiveness against mycobacteria has been assessed. In this work, we demonstrate for the first time the activities of mefloquine and its oxazolidine derivative compound 1E in a murine model of TB infection following administration of both drugs by the oral route. The effects of associations between mefloquine or 1E with the clinically used antituberculosis drugs isoniazid, rifampicin, ethambutol, moxifloxacin and streptomycin were also investigated. Importantly, combination of mefloquine with isoniazid and of 1E with streptomycin showed a two-fold decrease in their minimum inhibitory concentrations (MICs). Moreover, no tested combinations demonstrated antagonist interactions. Here we describe novel evidence on the activity of mefloquine and 1E against a series of quinolone-resistant M. tuberculosis strains. These data show MICs against quinolone-resistant strains (0.5–8 µg/mL) similar to or lower than those previously reported for multidrug-resistant strains. Taking these results together, we can suggest the use of mefloquine or 1E in combination with clinically available drugs, especially in the case of resistant forms of TB.

The objective of this study was to examine the in vitro synergism of three-drug combinations against Mycobacterium tuberculosis (levofloxacin/linezolid/ethambutol, levofloxacin/amikacin/ethambutol and levofloxacin/linezolid/amikacin) using the time-kill curves method. In total, 8 multidrug-resistant and 12 drug-susceptible M. tuberculosis isolates were used. Minimum inhibitory concentrations (MICs) of the isolates for each drug were determined by the proportions method. Time-kill curves were studied for the three combinations proposed over 14 days using two different protocols. In protocol 1, 0.5× MIC for each drug was used. In protocol 2, 0.5× MIC for levofloxacin and linezolid and 0.25× MIC for amikacin and ethambutol were used. The MICs for all of the isolates studied were 0.5 mg/L for levofloxacin and linezolid and 2.5 mg/L for ethambutol and amikacin. All of the combinations displayed an additive activity compared with the most active individual drug. In conclusion, these results demonstrate that the three combinations tested were equally effective against M. tuberculosis isolates. The study of antituberculous combinations using in vitro methods is an excellent first step to predict their effect in clinical development phases as well as to test new regimens of the antituberculous drugs currently available.

Multidrug resistance has become a problem in the management of tuberculosis, with an urgent need for research into new drugs as well as the development of efficacious drug combinations and regimens. The main objective of this study was to assess and compare the efficacy of three antituberculous combinations (clofazimine/pretomanid/levofloxacin, clofazimine/pretomanid/moxifloxacin and clofazimine/pretomanid/UB-8902) against multidrug-resistant (MDR) and drug-susceptible clinical isolates of Mycobacterium tuberculosis using an in vitro adaptation of the chequerboard assay. A total of 7 MDR and 11 drug-susceptible clinical isolates were studied. The fractional inhibitory concentration index (FICI) was interpreted as synergism when the value was0.75, antagonism when it was4 and additive activity between these two values. The FICI of all of the combinations ranged from 1.2 to 2.3, showing additive activity against all of the isolates. No differences were found between MDR and drug-susceptible isolates. In conclusion, the three combinations are effective against M. tuberculosis with equal effects. Moreover, in vitro testing of drug combinations could be useful to predict their clinical use.

A total of 243 clinical isolates of the Mycobacterium genus were studied, 143 and 100 using two protocols (Protocol v2 and Protocol v3, respectively) provided by the manufacturer. The overall correlation of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with the standard identification methods was 63.8 %. The rate of misidentification was 3.2 %, mainly affecting very close species. In Protocol v2, the correlation was 57.3 %, being greater in solid than in liquid media (71.7 % vs. 44.7 %, p