In vitro and in vivo local tolerability of a synergistic anti-tuberculosis drug combination intended for pulmonary delivery.

A drug combination, vancomycin (VAN) plus tetrahydrolipstatin (THL), has demonstrated an effective synergistic action in vitro against Mycobacterium tuberculosis (Mtb). The poor oral bioavailability of VAN and THL and the predominant tropism of Mtb infection to the lungs make their pulmonary administration very attractive. To evaluate their local tolerability, bronchial cells, alveolar cells and monocytes were exposed to concentrations around and above their minimal inhibitory concentration (MIC). The VAN had no inhibitory activity on the tested human cell lines, even at a concentration 125 times higher than its MIC, whereas the THL, alone or in combination with VAN, presented a cytostatic action. Monolayer epithelium showed no significant irreversible damage at concentrations up to 100 times the combination MIC. BALB/cAnNRj mice exposed to concentration of 50 times the combination MIC delivered endotracheally 3 times a week for 3 weeks showed no clinical signs or significant weight loss. The increase of proinflammatory biomarkers (i.e., IL-1, IL-6, TNF-α and proportion of inflammatory cells) and cytotoxicity in bronchoalveolar lavage fluid (BALF) were non-significant. Lung histopathology did not show significant tissue damage. The VAN/THL combination at doses up to 50 times the combination MIC is found to be thus well tolerated by pulmonary route. This study is a promising result and encouraging further investigations of pulmonary administration of VAN/THL combination as dry powder for anti-tuberculosis treatment.

Pyrrovobasine, hybrid alkylated pyrraline monoterpene indole alkaloid pseudodimer discovered using a combination of mass spectral and NMR-based machine learning annotations.

A new vobasine-tryptamine-based monoterpene indole alkaloid pseudodimer was isolated from the stem bark of Voacanga africana. As a minor constituent occurring in a thoroughly investigated plant, this molecule was targeted based on a molecular networking strategy and a rational MS2-guided phytochemical investigation led to its isolation. Its structure was formally established based on HRMS, 1D/2D NMR data, and the application of the tool Small Molecule Accurate Recognition Technology (SMART 2.0). Its absolute configuration was assigned by the exciton chirality method and TD-DFT ECD calculations. Besides featuring an unprecedented intermonomeric linkage in the small group of vobasine/tryptamine hybrids, pyrrovobasine also represents the first pyrraline-containing representative in the whole monoterpene indole alkaloids group. Biosynthetic hypotheses possibly underpinning these structural oddities are proposed here.

Voatriafricanines A and B, Trimeric Vobasine-Aspidosperma-Aspidosperma Alkaloids from Voacanga africana.

Voatriafricanines A and B (1 and 2), the first examples of vobasine-aspidosperma-aspidosperma monoterpene trisindole alkaloids, were isolated from the stem barks of Voacanga africana, guided by a molecular networking strategy. Their structures, including absolute configurations, were elucidated by spectroscopic methods and ECD calculations. Compounds 1 and 2 possess intramolecular hydrogen bonding, sufficiently robust to transfer homonuclear and heteronuclear magnetizations. Compound 1 exhibited potent antimycobacterial activity with no discernible cytotoxic activity.

Genome-wide association study identifies favorable SNP alleles and candidate genes for frost tolerance in pea.

BACKGROUND: Frost is a limiting abiotic stress for the winter pea crop (Pisum sativum L.) and identifying the genetic determinants of frost tolerance is a major issue to breed varieties for cold northern areas. Quantitative trait loci (QTLs) have previously been detected from bi-parental mapping populations, giving an overview of the genome regions governing this trait. The recent development of high-throughput genotyping tools for pea brings the opportunity to undertake genetic association studies in order to capture a higher allelic diversity within large collections of genetic resources as well as to refine the localization of the causal polymorphisms thanks to the high marker density. In this study, a genome-wide association study (GWAS) was performed using a set of 365 pea accessions. Phenotyping was carried out by scoring frost damages in the field and in controlled conditions. The association mapping collection was also genotyped using an Illumina Infinium® BeadChip, which allowed to collect data for 11,366 single nucleotide polymorphism (SNP) markers. RESULTS: GWAS identified 62 SNPs significantly associated with frost tolerance and distributed over six of the seven pea linkage groups (LGs). These results confirmed 3 QTLs that were already mapped in multiple environments on LG III, V and VI with bi-parental populations. They also allowed to identify one locus, on LG II, which has not been detected yet and two loci, on LGs I and VII, which have formerly been detected in only one environment. Fifty candidate genes corresponding to annotated significant SNPs, or SNPs in strong linkage disequilibrium with the formers, were found to underlie the frost damage (FD)-related loci detected by GWAS. Additionally, the analyses allowed to define favorable haplotypes of markers for the FD-related loci and their corresponding accessions within the association mapping collection. CONCLUSIONS: This study led to identify FD-related loci as well as corresponding favorable haplotypes of markers and representative pea accessions that might to be used in winter pea breeding programs. Among the candidate genes highlighted at the identified FD-related loci, the results also encourage further attention to the presence of C-repeat Binding Factors (CBF) as potential genetic determinants of the frost tolerance locus on LG VI.

Evaluation of the effectiveness of high-risk human papilloma self-sampling test for cervical cancer screening in Bolivia.

BACKGROUND: In Bolivia the incidence and mortality rates of uterine cervix cancer are the highest in America. The main factor contributing to this situation is the difficulty of establishing and maintaining quality prevention programs based on cytology. We aimed to evaluate the effectiveness of HR-HPV testing on self-collected samples to detect cervical intra-epithelial neoplasia and identify the best combination of screening tests. METHODS: A total of 469 women, divided in two groups, were included in this study. The first group included 362 women that underwent three consecutively primary screening tests: self-collected sampling for HR-HPV detection, conventional cervical cytology and visual inspection under acetic acid (VIA). The second group included 107 women referred with a positive HR-HPV test that underwent conventional cervical cytology and VIA. The presence of high grade intraepithelial lesion (CIN 2+) or invasive cancer was verified by colposcopy and biopsy. RESULT: In the screening group the sensitivity to detect high grade intraepithelial lesion (CIN 2+) or invasive cancer were 100, 76, 44% for the VIA, HR-HPV test and cytology, respectively. In the referred group, the sensitivity to detect high grade intraepithelial lesion (CIN 2+) or invasive cancer by VIA and cytology were 100 and 81%, respectively. CONCLUSIONS: VIA and HR-HPV self-sampling were the best combination to detect CIN2+ lesions. Cytology analysis gave the poorest performance.

Isoniazid Bactericidal Activity Involves Electron Transport Chain Perturbation.

Accumulating evidence suggests that the bactericidal activity of some antibiotics may not be directly initiated by target inhibition. The activity of isoniazid (INH), a key first-line bactericidal antituberculosis drug currently known to inhibit mycolic acid synthesis, becomes extremely poor under stress conditions, such as hypoxia and starvation. This suggests that the target inhibition may not fully explain the bactericidal activity of the drug. Here, we report that INH rapidly increased Mycobacterium bovis BCG cellular ATP levels and enhanced oxygen consumption. The INH-triggered ATP increase and bactericidal activity were strongly compromised by Q203 and bedaquiline, which inhibit mycobacterial cytochrome bc1 and FoF1 ATP synthase, respectively. Moreover, the antioxidant N-acetylcysteine (NAC) but not 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL) abrogated the INH-triggered ATP increase and killing. These results reveal a link between the energetic (ATP) perturbation and INH's killing. Furthermore, the INH-induced energetic perturbation and killing were also abrogated by chemical inhibition of NADH dehydrogenases (NDHs) and succinate dehydrogenases (SDHs), linking INH's bactericidal activity further to the electron transport chain (ETC) perturbation. This notion was also supported by the observation that INH dissipated mycobacterial membrane potential. Importantly, inhibition of cytochrome bd oxidase significantly reduced cell recovery during INH challenge in a culture settling model, suggesting that the respiratory reprogramming to the cytochrome bd oxidase contributes to the escape of INH killing. This study implicates mycobacterial ETC perturbation through NDHs, SDHs, cytochrome bc1, and FoF1 ATP synthase in INH's bactericidal activity and pinpoints the participation of the cytochrome bd oxidase in protection against this drug under stress conditions.

Assessment of a new low-cost, PCR-based strategy for high-risk human papillomavirus DNA detection for cervical cancer prevention.

BACKGROUND: HPV test implementation as a primary screening tool has the potential to decrease cervical cancer incidence as shown by several studies around the world. However, in many low-resource settings, the HPV test introduction has been backed down mainly due to its price. In this study, we present a novel low-cost strategy involving simple devices and techniques for high-risk human papillomavirus (HR-HPV) detection. The analytical performance to detect HR-HPV infections of this novel strategy was assessed by comparing it with the Hybrid Capture 2 system (HC2), which is used as gold standard. METHODS: Paired-cervical samples were collected from 541 women assisting to gynecological services in an outpatient clinic. One sample was transported in the Hybrid Capture Standard Transport Medium for HR-HPV detection by the HC2. The second sample was transported on glass slide for detection by PCR-based techniques (GP-EIA, BSGP-EIA and pU 1 M-L/2R). RESULTS: The level of agreement between the PCR-based techniques and HC2 system was determined with the Cohen's kappa value. The kappa values between HC2 and GP-EIA, BSGP-EIA and pU 1 M-L/2R were 0.71 (CI 95% 0.63-0.78), 0.78 (CI 95% 0.71-0.84) and 0.63 (CI 95% 0.55-0.72), respectively. However, when the results from both BSGP-EIA and pU 1 M-L/2R were combined, the level of agreement with HC2 was increased to 0.82 (CI 95% 0.76-0.88), reflecting a very good agreement between the two HR-HPV detection strategies. Furthermore, the sensitivity of both techniques combined was also increased compared to the BSGP-EIA (88.7% vs 77.4%) and the pU (88.7 vs 60.9%) without penalizing the specificity obtained with the BSGP-EIA (95.1% vs 96.9%) and the pU (95.1% vs 96.5%). CONCLUSIONS: This novel strategy, combining two PCR-based techniques for HR-HPV detection, could be useful for cervical cancer screening in self-collected samples in low-income countries.

Evaluation of the self-sampling for cervical cancer screening in Bolivia.

BACKGROUND: Incidence and mortality rates of cervical cancer in Bolivia are the highest in Latin America. Vaginal cell self-sampling can improve screening coverage. Information on common reasons for low screening coverage and preferences for future screening are essential to reduce cervical cancer incidence. We aimed to evaluate the knowledge about human papillomavirus (HPV) and cervical cancer of Bolivian women from urban, peri-urban and rural areas of Cochabamba and to determine their degree of acceptability and confidence towards vaginal HPV self-sampling. In addition, we assessed the impact of self-sampling on cervical cancer screening coverage in a selected peri-urban area. METHODS: We gathered information from women living in urban, peri-urban and rural areas of Cochabamba province in Bolivia using two different structured questionnaires. In Survey1, we collected information from 222 women about their knowledge on HPV and cervical cancer. In Survey 2, the acceptance and confidence towards vaginal HPV self-sampling compared to the physician-sampling was assessed in 221 women. A non-probabilistic stratified sampling by areas was carried out for the two questionnaires. In the third phase of the study, we determined the impact of HPV self-sampling collection on screening coverage in a peri-urban area of Cochabamba. RESULTS: Bolivian women knew little or nothing about cervical cancer and HPV infection in all areas. They all found self-sampling collection easier to perform (86.9 to 93.2%) and more comfortable (79.4 to 83.3%) compared to physician sampling. Sampling accuracy to detect cervical cancer was probably higher in their point of view when it was taken by physician (35.1 to 63.5%). However in rural areas women preferred self-sampling. Accordingly, the campaign of vaginal HPV self-sampling in this peri-urban area increased screening coverage, reaching in three months the annual rate average. CONCLUSIONS: The knowledge about cervical cancer and HPV infection is poor in Bolivia. Despite greater acceptance of the vaginal HPV self-sampling in all areas, women kept greater confidence in the screening performed by the gynecologist although HPV self-sampling improved coverage rate.

Aloe Emodin Reduces Phthiodiolone Dimycocerosate Potentiating Vancomycin Susceptibility on Mycobacteria.

Treatment of tuberculosis still represent a major public health issue. The emergence of multi-and extensively-drug resistant (MDR and XDR) Mycobacterium tuberculosis clinical strains further pinpoint the urgent need for new anti-tuberculous drugs. We previously showed that vancomycin can target mycobacteria lacking cell wall integrity, especially those lacking related phthiocerol and phthiodolone dimycocerosates, PDIM A and PDIM B, respectively. As aloe emodin was previously hypothesized to be able to target the synthesis of mycobacterial cell wall lipids, we tested its ability to potentiate glycopeptides antimycobacterial activity. The aloe emodin with the vancomycin induced a combination effect beyond simple addition, close to synergism, at a concentration lower to reported IC50 cytotoxic value, on M. bovis BCG and on H37Rv M. tuberculosis. Interestingly, out of six MDR and pre-XDR clinical strains, one showed a strong synergic susceptibility to the drug combination. Mycobacterial cell wall lipid analyses highlighted a selective reduction of PDIM B by aloe emodin.

Self-sampling for human papillomavirus DNA detection: a preliminary study of compliance and feasibility in BOLIVIA.

BACKGROUND: Cervical cancer incidence and mortality rates in Bolivia are among the highest in Latin America. This investigation aims to evaluate the possibility of using simple devices, e.g. a cotton swab and a glass slide, for self-sampling in order to detect human papillomavirus (HPV) DNA by PCR in cervico-vaginal cells. METHODS: In the first phase of our study we evaluated the use of a glass slide as a transport medium for cervical cells. A physician took paired-cervical samples from 235 women. One sample was transported in Easyfix® solution and the other sample was smeared over a glass slide. Both were further analyzed and compared for human DNA recovery and HPV detection. A kappa value was determined to evaluate the agreement between the HPV DNA detection rates. In the second phase of the study, 222 women from the urban, peri-urban and rural regions of Cochabamba were requested to perform self-sampling using the following devices: a cotton swab combined with a glass slide, and a vaginal tampon. Women gave their opinion about the self-sampling technique. Finally, the agreement for high risk-HPV detection between self- and physician-collected samples was performed in 201 samples in order to evaluate the self-sampling technique. RESULTS: Firstly, the comparison between Easyfix® solution and the glass slide to transport clinical samples gave a good agreement for HPV DNA detection (κ = 0.71, 95% CI 0.60-0.81). Secondly, self-sampling, especially with cotton swab combined with glass slide, would generally be preferred over clinician sampling for a screening program based on HPV detection. Finally, we showed a good agreement between self- and physician collected samples for high risk-HPV detection (κ = 0.71, 95% CI 0.55-0.88). CONCLUSIONS: Simple devices such as a cotton swab and a glass slide can be used to perform self-sampling and HPV DNA detection. Furthermore, most Bolivian women preferred self-sampling over clinician-sampling for cervical cancer screening.

In vitro Study of Five Herbs Used Against Microbial Infections in Burundi.

The emergence of antimicrobial resistant infectious diseases remains a major threat to worldwide public health, in developed and in developing countries. Therefore, new antimicrobial agents acting by new mechanisms of action are urgently needed. As plants used in traditional medicine may help to overcome these problems, Justicia subsessilis, Platostoma rotundifolium, Pavetta ternifolia, Stomatanthes africanus, and Virectaria major (plants highly cited to be used against microbial infections in traditional Burundian medicine) were studied to assess their traditional use efficacy. We conducted a preliminary phytochemical screening of the extracts, as well as their direct and indirect (effect on antibiotic resistance) antibacterial activity on four bacterial strains (Staphylococcus sp. and Escherichia coli) by broth microdilution methods. All five medicinal plants investigated in this work were found to have direct antibacterial activity against all tested bacterial strains (minimum inhibitory concentration = 62.5-1000 µg/mL) that may support the use of these species in traditional Burundian medicine. Extracts (with no direct antibacterial activity), tested at 200 µg/mL, decreased the MIC values of ß-lactams and aminoglycoside antibiotics by a factor of 2 to 64-fold. These interactions between plant extracts and antibiotics could open an avenue of research against antibiotic resistance. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of Lipid-Lowering Drugs on Vancomycin Susceptibility of Mycobacteria.

Tuberculosis is still a cause of major concern, partly due to the emergence of multidrug-resistant strains. New drugs are therefore needed. Vancomycin can target mycobacteria with cell envelope deficiency. In this study, we used a vancomycin susceptibility assay to detect drugs hampering lipid synthesis in Mycobacterium bovis BCG and in Mycobacterium tuberculosis We tested three drugs already used to treat human obesity: tetrahydrolipstatin (THL), simvastatin, and fenofibrate. Only vancomycin and THL were able to synergize on M. bovis BCG and on M. tuberculosis, although mycobacteria could also be inhibited by simvastatin alone. Lipid analysis allowed us to identify several lipid modifications in M. tuberculosis H37Rv treated with those drugs. THL treatment mainly reduced the phthiocerol dimycocerosate (PDIM) content in the mycobacterial cell wall, providing an explanation for the synergy, since PDIM deficiency has been related to vancomycin susceptibility. Proteomic analysis suggested that bacteria treated with THL, in contrast to bacteria treated with simvastatin, tried to recover, inducing, among other reactions, lipid synthesis. The combination of THL and vancomycin should be considered a promising solution in developing new strategies to treat multidrug-resistant tuberculosis.

Increased Vancomycin Susceptibility in Mycobacteria: a New Approach To Identify Synergistic Activity against Multidrug-Resistant Mycobacteria.

Mycobacterium tuberculosis is wrapped in complex waxes, impermeable to most antibiotics. Comparing Mycobacterium bovis BCG and M. tuberculosis mutants that lack phthiocerol dimycocerosates (PDIM) and/or phenolic glycolipids with wild-type strains, we observed that glycopeptides strongly inhibited PDIM-deprived mycobacteria. Vancomycin together with a drug targeting lipid synthesis inhibited multidrug-resistant (MDR) and extensively drug-resistant (XDR) clinical isolates. Our study puts glycopeptides in the pipeline of potential antituberculosis (TB) agents and might provide a new antimycobacterial drug-screening strategy.

Genetic variability and QTL mapping of freezing tolerance and related traits in Medicago truncatula.

Freezing is a major environmental limitation to crop productivity for a number of species including legumes. We investigated the genetic determinism of freezing tolerance in the model legume Medicago truncatula Gaertn (M. truncatula). After having observed a large variation for freezing tolerance among 15 M. truncatula accessions, the progeny of a F6 recombinant inbred line population, derived from a cross between two accessions, was acclimated to low above-freezing temperatures and assessed for: (a) number of leaves (NOL), leaf area (LA), chlorophyll content index (CCI), shoot and root dry weights (SDW and RDW) at the end of the acclimation period and (b) visual freezing damage (FD) during the freezing treatment and 2 weeks after regrowth and foliar electrolyte leakage (EL) 2 weeks after regrowth. Consistent QTL positions with additive effects for FD were found on LG1, LG4 and LG6, the latter being the most explanatory (R (2) ≈ 40 %). QTL for NOL, QTL for EL, NOL and RDW, and QTL for EL and CCI colocalized with FD QTL on LG1, LG4 and LG6, respectively. Favorable alleles for these additive effects were brought by the same parent suggesting that this accession contributes to superior freezing tolerance by affecting plants' capacity to maintain growth at low above-freezing temperatures. No epistatic effects were found between FD QTL, but for each of the studied traits, 3-6 epistatic effects were detected between loci not detected directly as QTL. These results open the way to the assessment of syntenic relationships between QTL for frost tolerance in M. truncatula and cultivated legume species.

The Mycobacterium bovis BCG GroEL1 Contributes to Isoniazid Tolerance in a Dormant-Like State Model.

Due to the Mycobacterium tuberculosis complex, including M. tuberculosis and M. bovis, tuberculosis still causes 1.6 million deaths per year. Therefore, efforts to improve tuberculosis treatment are necessary. We previously showed that the GroEL1 protein is involved in antibiotic intrinsic resistance. Indeed, the M. bovis BCG cpn60.1 gene (encoding GroEL1)-disrupted strain (Δcpn60.1) exhibits higher rifampicin and vancomycin susceptibility due to defective cell wall integrity. Here, we show that during hypoxia-triggered growth stasis, in the Wayne dormancy model, the mutant exhibited comparable rifampicin and ethionamide susceptibility but higher isoniazid susceptibility compared to the wild-type strain. Although the Δcpn60.1 strain showed compromised induction of the DosR regulon, growth stasis was achieved, but an ATP burst and a higher reactive oxygen species (ROS) production were observed in the isoniazid-treated Δcpn60.1 strain. GroEL1 could contribute to INH tolerance by reducing ROS.

Clarifying the Configuration of Pandamine by an Extensive Spectroscopic Reinvestigation of the Authentic 1964 Sample.

Since its partial configurational assignment in 1964, pandamine has not been isolated or obtained by total synthesis. For decades, different works representing the structure of pandamine for illustrative purposes have lent different configurations to this molecule, causing tenacious confusion about the structure of this ansapeptide. A comprehensive spectroscopic analysis of the authentic pandamine sample led to the complete and unambiguous assignment of its configuration, 59 years after its isolation. In addition to ascertaining and completing the initial structural deductions by a state-of-the-art set of analytical techniques, the purpose of this study is also to clarify the literature in a context in which various erroneous structures have been attributed to pandamine for half a century. While fully in agreement with Goutarel's conclusions, the specific example of pandamine should serve as a cautionary tale to any chemist interested in natural products, encouraging access to initial structural assignments rather than relying solely on subsequent, possibly erroneous, structure depictions of a natural product.

Telacebec Interferes with Virulence Lipid Biosynthesis Protein Expression and Sensitizes to Other Antibiotics.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a public health issue, particularly due to multi-drug-resistant Mtb. The bacillus is wrapped in a waxy envelope containing lipids acting as essential virulence factors, accounting for the natural antibiotic resistance of mycobacteria. Telacebec (previously known as Q203) is a promising new anti-TB agent inhibiting the cytochrome bc1 complex of a mycobacterial electron transport chain (ETC). Here, we show that the telacebec-challenged M. bovis BCG exhibited a reduced expression of proteins involved in the synthesis of phthiocerol dimycocerosates (PDIMs)/phenolic glycolipids (PGLs), lipid virulence factors associated with cell envelope impermeability. Consistently, telacebec, at concentrations lower than its MIC, downregulated the transcription of a PDIM/PGL-synthesizing operon, suggesting a metabolic vulnerability triggered by the drug. The drug was able to synergize on BCG with rifampicin or vancomycin, the latter being a drug exerting a marginal effect on PDIM-bearing bacilli. Telacebec at a concentration higher than its MIC had no detectable effect on cell wall PDIMs, as shown by TLC analysis, a finding potentially explained by the retaining of previously synthesized PDIMs due to the inhibition of growth. The study extends the potential of telacebec, demonstrating an effect on mycobacterial virulence lipids, allowing for the development of new anti-TB strategies.

Untargeted Metabolomics Approach Correlated Enniatin B Mycotoxin Presence in Cereals with Kashin-Beck Disease Endemic Regions of China.

Kashin-Beck disease (KBD) is a multifactorial endemic disease that only occurs in specific Asian areas. Mycotoxin contamination, especially from the Fusarium spp., has been considered as one of the environmental risk factors that could provoke chondrocyte and cartilage damage. This study aimed to investigate whether new mycotoxins could be identified in KBD-endemic regions as a potential KBD risk factor. This was investigated on 292 barley samples collected in Tibet during 2009-2016 and 19 wheat samples collected in Inner Mongolia in 2006, as control, from KBD-endemic and non-endemic areas. The LC-HRMS(/MS) data, obtained by a general mycotoxin extraction technic, were interpreted by both untargeted metabolomics and molecular networks, allowing us to identify a discriminating compound, enniatin B, a mycotoxin produced by some Fusarium spp. The presence of Fusarium spp. DNA was detected in KBD-endemic area barley samples. Further studies are required to investigate the role of this mycotoxin in KBD development in vivo.

Antimycobacterial Activities of Hydroxamic Acids and Their Iron(II/III), Nickel(II), Copper(II) and Zinc(II) Complexes.

Hydroxamic acid (HA) derivatives display antibacterial and antifungal activities. HA with various numbers of carbon atoms (C2, C6, C8, C10, C12 and C17), complexed with different metal ions, including Fe(II/III), Ni(II), Cu(II) and Zn(II), were evaluated for their antimycobacterial activities and their anti-biofilm activities. Some derivatives showed antimycobacterial activities, especially in biofilm growth conditions. For example, 20-100 µM of HA10Fe2, HA10FeCl, HA10Fe3, HA10Ni2 or HA10Cu2 inhibited Mycobacterium tuberculosis, Mycobacterium bovis BCG and Mycobacterium marinum biofilm development. HA10Fe2, HA12Fe2 and HA12FeCl could even attack pre-formed Pseudomonas aeruginosa biofilms at higher concentrations (around 300 µM). The phthiocerol dimycocerosate (PDIM)-deficient Mycobacterium tuberculosis H37Ra was more sensitive to the ion complexes of HA compared to other mycobacterial strains. Furthermore, HA10FeCl could increase the susceptibility of Mycobacterium bovis BCG to vancomycin. Proteomic profiles showed that the potential targets of HA10FeCl were mainly related to mycobacterial stress adaptation, involving cell wall lipid biosynthesis, drug resistance and tolerance and siderophore metabolism. This study provides new insights regarding the antimycobacterial activities of HA and their complexes, especially about their potential anti-biofilm activities.

Easy, Flexible and Standardizable Anti-Nascent Biofilm Activity Assay to Assess Implant Materials.

Medical implants have improved the quality of life of many patients. However, surgical intervention may eventually lead to implant microbial contamination. The aims of this research were to develop an easy, robust, quantitative assay to assess surface antimicrobial activities, especially the anti-nascent biofilm activity, and to identify control surfaces, allowing for international comparisons. Using new antimicrobial assays to assess the inhibition of nascent biofilm during persistent contact or after transient contact with bacteria, we show that the 5 cent Euro coin or other metal-based antibacterial coins can be used as positive controls, as more than 4 log reduction on bacterial survival was observed when using either S. aureus or P. aeruginosa as targets. The methods and controls described here could be useful to develop an easy, flexible and standardizable assay to assess relevant antimicrobial activities of new implant materials developed by industries and academics.