Biofilm reactors filled with Stick-bed Biofix and Swim-bed Biofringe biomass carriers in treating chitin production wastewater containing high salinity.

The production of chitin generates wastewater containing high content of organic compounds, nutrients, and salinity, thus a biofilm system including anaerobic-anoxic-aerobic bioreactors was employed. This study aims to evaluate the performance of Stick-bed Biofix and Swim-bed Biofringe added to bioreactors as a biomass carrier in order to enhance biomass concentration. The results indicated that the organic removal has been insignificantly affected by high salinity, the removal efficiency was obtained at 95 ± 2% corresponding to a rate of 5.78 ± 1.10 kg COD/m3/d. Otherwise, the nitrogen removal rate was achieved at around 0.45 ± 0.17 kg N/m3/d and strongly decreased to 0.24 ± 0.10 kg N/m3/d under high salinity of 18,000 mg/L and a high loading rate of 1.03 ± 0.10 kg N/m3/d. Phosphorus removal was obtained at 0.032-0.057 kg P/m3/d and decreased by 1.5 times when the salinity is over 10,000 mg/L although the influent load was strongly reduced by pre-treatment. Besides, the biofilm system can also remove around 50% of calcium ions which causes high salinity in chitin production wastewater.

Genomic alterations involved in fluoroquinolone resistance development in Staphylococcus aureus.

AIM: Fluoroquinolone (FQ) is a potent antibiotic class. However, resistance to this class emerges quickly which hinders its application. In this study, mechanisms leading to the emergence of multidrug-resistant (MDR) Staphylococcus aureus (S. aureus) strains under FQ exposure were investigated. METHODOLOGY: S. aureus ATCC 29213 was serially exposed to ciprofloxacin (CIP), ofloxacin (OFL), or levofloxacin (LEV) at sub-minimum inhibitory concentrations (sub-MICs) for 12 days to obtain S. aureus -1 strains and antibiotic-free cultured for another 10 days to obtain S. aureus-2 strains. The whole genome (WGS) and target sequencing were applied to analyze genomic alterations; and RT-qPCR was used to access the expressions of efflux-related genes, alternative sigma factors, and genes involved in FQ resistance. RESULTS: A strong and irreversible increase of MICs was observed in all applied FQs (32 to 128 times) in all S. aureus-1 and remained 16 to 32 times in all S. aureus-2. WGS indicated 10 noticeable mutations occurring in all FQ-exposed S. aureus including 2 insdel mutations in SACOL0573 and rimI; a synonymous mutation in hslO; and 7 missense mutations located in an untranslated region. GrlA, was found mutated (R570H) in all S. aureus-1 and -2. Genes encoding for efflux pumps and their regulator (norA, norB, norC, and mgrA); alternative sigma factors (sigB and sigS); acetyltransferase (rimI); methicillin resistance (fmtB); and hypothetical protein BJI72_0645 were overexpressed in FQ-exposed strains. CONCLUSION: The emergence of MDR S. aureus was associated with the mutations in the FQ-target sequences and the overexpression of efflux pump systems and their regulators.

Novel Synergies and Isolate Specificities in the Drug Interaction Landscape of Mycobacterium abscessus.

Mycobacterium abscessus infections are difficult to treat and are often considered untreatable without tissue resection. Due to the intrinsic drug-resistant nature of the bacteria, combination therapy of three or more antibiotics is recommended. A major challenge in treating M. abscessus infections is the absence of a universal combination therapy with satisfying clinical success rates, leaving clinicians to treat infections using antibiotics lacking efficacy data. We systematically measured drug combinations in M. abscessus to establish a resource of drug interaction data and identify patterns of synergy to help design optimized combination therapies. We measured 191 pairwise drug combination effects among 22 antibacterials and identified 71 synergistic pairs, 54 antagonistic pairs, and 66 potentiator-antibiotic pairs. We found that commonly used drug combinations in the clinic, such as azithromycin and amikacin, are antagonistic in the lab reference strain ATCC 19977, whereas novel combinations, such as azithromycin and rifampicin, are synergistic. Another challenge in developing universally effective multidrug therapies for M. abscessus is the significant variation in drug response between isolates. We measured drug interactions in a focused set of 36 drug pairs across a small panel of clinical isolates with rough and smooth morphotypes. We observed strain-dependent drug interactions that cannot be predicted from single-drug susceptibility profiles or known drug mechanisms of action. Our study demonstrates the immense potential to identify synergistic drug combinations in the vast drug combination space and emphasizes the importance of strain-specific combination measurements for designing improved therapeutic interventions.

Design principles to assemble drug combinations for effective tuberculosis therapy using interpretable pairwise drug response measurements.

A challenge in tuberculosis treatment regimen design is the necessity to combine three or more antibiotics. We narrow the prohibitively large search space by breaking down high-order drug combinations into drug pair units. Using pairwise in vitro measurements, we train machine learning models to predict higher-order combination treatment outcomes in the relapsing BALB/c mouse model. Classifiers perform well and predict many of the >500 possible combinations among 12 antibiotics to be improved over bedaquiline + pretomanid + linezolid, a treatment-shortening regimen compared with the standard of care in mice. We reformulate classifiers as simple rulesets to reveal guiding principles of constructing combination therapies for both preclinical and clinical outcomes. One example ruleset combines a drug pair that is synergistic in a dormancy model with a pair that is potent in a cholesterol-rich growth environment. These rulesets are predictive, intuitive, and practical, thus enabling rational construction of drug combinations.

C25-modified rifamycin derivatives with improved activity against Mycobacterium abscessus.

Infections caused by Mycobacterium abscessus are difficult to treat due to its intrinsic resistance to most antibiotics. Formation of biofilms and the capacity of M. abscessus to survive inside host phagocytes further complicate eradication. Herein, we explored whether addition of a carbamate-linked group at the C25 position of rifamycin SV blocks enzymatic inactivation by ArrMab, an ADP-ribosyltransferase conferring resistance to rifampicin (RMP). Unlike RMP, 5j, a benzyl piperidine rifamycin derivative with a morpholino substituted C3 position and a naphthoquinone core, is not modified by purified ArrMab. Additionally, we show that the ArrMab D82 residue is essential for catalytic activity. Thermal profiling of ArrMab in the presence of 5j, RMP, or rifabutin shows that 5j does not bind to ArrMab. We found that the activity of 5j is comparable to amikacin against M. abscessus planktonic cultures and pellicles. Critically, 5j also exerts potent antimicrobial activity against M. abscessus in human macrophages and shows synergistic activity with amikacin and azithromycin.

Factors influencing adverse events following immunization with AZD1222 in Vietnamese adults during first half of 2021.

BACKGROUND: COVID-19 vaccines have been speedily developed and deployed. The more vaccine doses are delivered to users, the more common adverse events following immunization (AEFI) are reported. This study aimed to identify factors affecting AEFI in Vietnamese people receiving the COVID-19 vaccine AZD1222 developed by AstraZeneca and Oxford University. METHODS: In July 2021, an online cross-sectional survey was conducted among Vietnamese who have been vaccinated with COVID-19 vaccines. The questionnaire collected demographic characteristics, medical history, types of injected vaccines, common AEFI, and post-vaccination activities from respondents. The effects of host-related factors on AEFI including 24 specific symptoms were also explored. RESULTS: After screening, 1028 participants who were Vietnamese, over 18 years old and received at least one dose of AZD1222, were included in the study. Only 40/1028 (3.9%) participants reported not having any AEFI, whereas 25/1028 (2.4%) reported to have severe symptoms. The most common AEFI were moderate fever (69.4%), muscle aches (68.6%), followed by fatigue/ sleepiness (62.5%), body aches (59.4%), headache (58.5%), pain at injection site (58.3%) and chills (45.7%). Data analysis showed that females complained about AEFI particularly gastrointestinal symptoms more frequently than males. Age of participants and number of doses were also important factors affecting AEFI as the increase of age or number of vaccine doses was associated with the decrease of self-reported AEFI frequency. CONCLUSIONS: This study provides a detailed assessment of risk factors associated with AEFI in Vietnamese people vaccinated with AZD1222. It seems that gender, age and vaccine doses are important factors affecting AEFI.

Systematic measurement of combination-drug landscapes to predict in vivo treatment outcomes for tuberculosis.

Lengthy multidrug chemotherapy is required to achieve a durable cure in tuberculosis. However, we lack well-validated, high-throughput in vitro models that predict animal outcomes. Here, we provide an extensible approach to rationally prioritize combination therapies for testing in in vivo mouse models of tuberculosis. We systematically measured Mycobacterium tuberculosis response to all two- and three-drug combinations among ten antibiotics in eight conditions that reproduce lesion microenvironments, resulting in >500,000 measurements. Using these in vitro data, we developed classifiers predictive of multidrug treatment outcome in a mouse model of disease relapse and identified ensembles of in vitro models that best describe in vivo treatment outcomes. We identified signatures of potencies and drug interactions in specific in vitro models that distinguish whether drug combinations are better than the standard of care in two important preclinical mouse models. Our framework is generalizable to other difficult-to-treat diseases requiring combination therapies. A record of this paper's transparent peer review process is included in the supplemental information.

Efficient Measurement of Drug Interactions with DiaMOND (Diagonal Measurement of N-Way Drug Interactions).

Treatment of tuberculosis necessitates combination therapy. Therefore, development of new tuberculosis therapies should consider multidrug effects because specific combinations may improve or reduce treatment efficacy through synergistic or antagonistic drug interactions, respectively. The standard assay of drug interactions is a checkerboard assay, wherein the drug-dose combinations are well-sampled across broad dose ranges. However, measuring three or more drugs in combination with a checkerboard assay is impractical due to the high number of measurements. We describe a protocol for efficient and quantitative measurement of drug interactions called diagonal measurement of n-way drug interactions (DiaMOND). DiaMOND is a geometric optimization of the checkerboard assay, using only the diagonal and axes of the checkerboard. This protocol describes how to perform DiaMOND experiments and analysis for Mycobacterium tuberculosis growth inhibition in standard growth conditions. As a guide on how to customize the DiaMOND assay, this protocol includes notes to modify the procedures for other growth conditions and outcome measures.

Pharmacokinetics and Target Attainment of SQ109 in Plasma and Human-Like Tuberculosis Lesions in Rabbits.

SQ109 is a novel well-tolerated drug candidate in clinical development for the treatment of drug-resistant tuberculosis (TB). It is the only inhibitor of the MmpL3 mycolic acid transporter in clinical development. No SQ109-resistant mutant has been directly isolated thus far in vitro, in mice, or in patients, which is tentatively attributed to its multiple targets. It is considered a potential replacement for poorly tolerated components of multidrug-resistant TB regimens. To prioritize SQ109-containing combinations with the best potential for cure and treatment shortening, one must understand its contribution against different bacterial populations in pulmonary lesions. Here, we have characterized the pharmacokinetics of SQ109 in the rabbit model of active TB and its penetration at the sites of disease-lung tissue, cellular and necrotic lesions, and caseum. A two-compartment model with first-order absorption and elimination described the plasma pharmacokinetics. At the human-equivalent dose, parameter estimates fell within the ranges published for preclinical species. Tissue concentrations were modeled using an "effect" compartment, showing high accumulation in lung and cellular lesion areas with penetration coefficients in excess of 1,000 and lower passive diffusion in caseum after 7 daily doses. These results, together with the hydrophobic nature and high nonspecific caseum binding of SQ109, suggest that multiweek dosing would be required to reach steady state in caseum and poorly vascularized compartments, similar to bedaquiline. Linking lesion pharmacokinetics to SQ109 potency in assays against replicating, nonreplicating, and intracellular M. tuberculosis showed SQ109 concentrations markedly above pharmacokinetic-pharmacodynamic targets in lung and cellular lesions throughout the dosing interval.

Impairment of chloroplast movement reduces growth and delays reproduction of Arabidopsis thaliana in natural and controlled conditions.

PREMISE: The importance of chloroplast movement for plant growth in constant, controlled light and of nonphotochemical quenching (NPQ) in variable, natural light are known. Here we concurrently investigated growth and reproduction of several Arabidopsis thaliana mutants to assess the relative importance of photoprotection via chloroplast movement and NPQ. METHODS: Plants were grown outdoors (natural conditions) or in a growth chamber with variable light and chilling temperatures (controlled conditions). Phenotypic growth and reproductive variables were determined at set times before maturity in wild-type (WT) and phot1, phot2, phot1phot2 (e.g., impaired chloroplast movement, stomatal conductance, leaf flattening), chup1 (impaired chloroplast movement), and npq1 (reduced NPQ) plants. RESULTS: Mutants were most adversely affected in natural conditions, with phot1phot2 and chup1 most severely impacted. These mutants bolted later and produced fewer leaves and siliques, less leaf biomass, and fewer secondary inflorescences than WT. In controlled conditions, leaf traits of these mutants were unaffected, but phot1phot2 bolted later and produced fewer secondary inflorescences and siliques than WT. For most variables, there were significant interactions between growth conditions and plant genotype. Many variables were correlated, but those relationships changed with growth conditions and genotype. CONCLUSIONS: Phenotypic variables at the time of the harvest were strongly affected by growth conditions and genotype. In natural conditions, phot1phot2 and chup1 mutants were most adversely affected, demonstrating the importance of chloroplast movement. In controlled conditions, only phot1phot2 was consistently affected, also emphasizing the important, pleiotropic effects of phototropins. In both conditions, NPQ was less important.

Coagulation of Chitin Production Wastewater from Shrimp Scraps with By-Product Chitosan and Chemical Coagulants.

Chitin production wastewater contains nutrient-rich organic and mineral contents. Coagulation of the wastewater with a natural coagulant such as by-product chitosan would be an economical and environmentally friendly method of treatment. This study investigated the treatment efficiencies of a preliminary sedimentation process followed by coagulation. The removal efficiencies for wastewater parameters were evaluated and compared for coagulants including by-product chitosan, polyaluminum chloride, and polyacryamide. The evaluation was based on the removal of wastewater turbidity and other criteria, including tCOD, sCOD, TKN, NH4+-N, TP, TSS, calcium, and crude protein. The results showed that the preliminary sedimentation (before coagulation) can remove over 80% of turbidity and more than 93% of TSS at pH 4 in 30 min. At optimal conditions, when the ratio of crude protein and calcium was 4.95, by-product chitosan dose of 77.5 mg·L-1 and pH = 8.3, the wastewater characteristics changes were tCOD 23%, sCOD 32%, TKN and ammonium 25%, TP 90%, TSS 84%, Ca2+ 29%, and crude protein 25%. The residue recovered through coagulation consists of up to 55 mg·g-1 crude protein, which is used for animal feed or crop fertilizer.

UV and NIR-Responsive Layer-by-Layer Films Containing 6-Bromo-7-hydroxycoumarin Photolabile Groups.

This paper describes polyelectrolyte multilayer films prepared by the layer-by-layer (LbL) technique capable of undergoing dissolution upon exposure to either ultraviolet or near-infrared light. Film dissolution is driven by photochemical deprotection of a random methacrylic copolymer with two types of side chains: (i) 6-bromo-7-hydroxycoumarinyl esters, photocleavable groups that are known to have substantial two-photon photolysis cross sections, and (ii) cationic residues from the commercially available monomer N,N-dimethylaminoethyl methacrylate (DMAEMA). In addition, the dependence of stability of both unirradiated and irradiated films on pH provides experimental evidence for the necessity of disrupting both ion-pairing and hydrophobic interactions between polyelectrolytes to realize film dissolution. This work therefore provides both new fundamental insight regarding photolabile LbL films and expands their applied capabilities to nonlinear photochemical processes.

Physiological versatility of the genus Rhodocista.

A new purple bacterium (strain T4), capable of heterotrophic aerobic and phototrophic anaerobic growth, was isolated from waste water of a noodle factory near Hanoi, Vietnam. A comparison of 16S rDNA sequences revealed its association with the genus Rhodocista. The isolate, tentatively named "Rhodocista hanoiensis", forms cysts after growth on butyrate-containing plates at 42 degrees C. The vegetative cells form short (under aerobic conditions) or long curve-shaped rods. In contrast to other species of this genus T4 does not need any supplines (growth factors, not synthesized by the organisms). Comparative studies of T4 with Rhodocista centenaria (Rhodospirillum centenum) and Rhodocista pekingensis revealed a remarkable physiological versatility regarding nutrient spectra and survival properties of this genus.