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International Journal of Biological... Jun 2024Human serum albumin (HSA) effectively binds to compounds having different molecular weight and thus facilitates their distribution in the living organisms. Thus, the...
Human serum albumin (HSA) effectively binds to compounds having different molecular weight and thus facilitates their distribution in the living organisms. Thus, the binding interactions between a potential antibacterial drug (levofloxacin) and synthesized choline based levofloxacinate conjugates with HSA have been explored. The binding efficacy and mechanism were explored by utilizing different spectroscopic techniques; UV-Visible, steady state fluorescence, time resolved fluorescence and esterase-like activity. The interactions between the ligands and protein were electrostatic as well as hydrophobic in nature. The influence of different ligands having different alkyl chain shows quenching of the fluorescence emission of HSA. The spontaneous binding/quenching of HSA with ligands was static in nature, validated by steady state and time resolved fluorescence spectroscopy. Also, the impact of these ligands on the conformation of the native HSA structure was evaluated by using circular dichroism spectroscopy. In combination to the structural change study, the native protein functionality was observed (in terms of 'esterase-like activity') which has been found to be on lower side due to ligand binding. Further, we have performed the reverse study to check the impact of HSA on the fluorescent fluoroquinolone drug. The current study may prove helpful in elucidating the chemico-biological interactions which may prove useful in the pharmaceuticals, pharmacology, and different biochemistry fields.
PubMed: 38852730
DOI: 10.1016/j.ijbiomac.2024.133011 -
International Journal of Antimicrobial... Jun 2024Nemonoxacin malate is a novel non-fluorinated quinolone for oral and intravenous (IV) administration. This phase 3 multicentre, randomised, double-blind, double-dummy,...
A multicentre, randomised, double-blind, double-dummy, parallel-controlled, phase 3 clinical trial assessing the efficacy and safety of intravenous nemonoxacin malate versus levofloxacin for community-acquired pneumonia in adult patients.
BACKGROUND
Nemonoxacin malate is a novel non-fluorinated quinolone for oral and intravenous (IV) administration. This phase 3 multicentre, randomised, double-blind, double-dummy, parallel-controlled clinical trial (NCT02205112) evaluated the efficacy and safety of IV nemonoxacin versus levofloxacin for treatment of community-acquired pneumonia (CAP) in adult patients.
METHODS
The eligible patients were randomised to receive 500 mg nemonoxacin or levofloxacin via IV infusion, once daily for 7-14 days. The primary endpoint was the clinical cure rate at test of cure (TOC) visit in the modified intent-to-treat (mITT) population. The efficacy and safety were also compared between nemonoxacin and levofloxacin in terms of secondary efficacy and safety endpoints.
RESULTS
Overall, 525 patients were randomised and treated with nemonoxacin (n=349) or levofloxacin (n=176). The clinical cure rate was 91.8% (279/304) for nemonoxacin and 85.7% (138/161) for levofloxacin in the mITT population (P> 0.05). The clinical efficacy of nemonoxacin was noninferior to levofloxacin in treatment of CAP. Nemonoxacin achieved microbiological success rate of 88.8% (95/107), while levofloxacin achieved 87.8% (43/49) (P > 0.05) at TOC visit in the bacteriological mITT population. The incidence of drug-related adverse events (AEs) was 37.1% in nemonoxacin group and 22.2% in levofloxacin group, mostly local reactions at the infusion site, nausea, elevated ALT/AST, and QT interval prolongation. The nemonoxacin-related AEs were mostly mild and resolved after discontinuation of nemonoxacin.
CONCLUSIONS
Nemonoxacin 500 mg IV once daily for 7-14 days is effective and safe and noninferior to levofloxacin for treating CAP in adult patients.
PubMed: 38851462
DOI: 10.1016/j.ijantimicag.2024.107235 -
European Journal of Pharmaceutics and... Jun 2024Immune rejection remains the major cause of corneal graft failure. Immunosuppressants (such as rapamycin; RAPA) adjunctive to antibiotics (such as levofloxacin...
Immune rejection remains the major cause of corneal graft failure. Immunosuppressants (such as rapamycin; RAPA) adjunctive to antibiotics (such as levofloxacin hydrochloride; Lev) are a clinical mainstay after corneal grafts but suffer from poor ocular bioavailability associated with severe side effects. In this study, we fabricated a Lev@RAPA micelle loaded cationic peptide-based hydrogel (NapFFKK) as a dual-drug delivery system by integrating RAPA micelles with Lev into a cationic NapFFKK hydrogel to potentially reduced the risk of corneal graft rejection. The properties of the resulting hydrogels were characterized using transmission electronmicroscopy and rheometer. Lev@RAPA micelles loaded NapFFKK hydrogel provided sustained in vitro drug release without compromising their inherent pharmacological activities. Topical instillation of Lev@RAPA micelles loaded NapFFKK hydrogel resulted in the great ocular tolerance and extended precorneal retention over 60min, thus significantly enhancing the ocular bioavailability of both Lev and RAPA. Overall, such dual-drug delivery system might be a promising formulation for the suppression of corneal graft failure.
PubMed: 38851460
DOI: 10.1016/j.ejpb.2024.114351 -
Journal of Global Antimicrobial... Jun 2024Hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKp) poses a significant threat to public health. This study reports an infection related to hv-CRKp in a...
OBJECTIVES
Hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKp) poses a significant threat to public health. This study reports an infection related to hv-CRKp in a premature infant and reveals its colistin resistance and evolutionary mechanisms within the host.
METHODS
Three KPC-producing CRKp strains were isolated from a patient with sepsis and CRKp osteoarthritis who had been receiving colistin antimicrobial therapy. The minimum inhibitory concentrations (MICs) of Ceftazidime,Ceftazidime-Avibactam(CAZ-AVI),Meropenem,Imipenem,Tigecycline,Amikacin,Minocycline,Sulfamethoxazole/Trimethoprim,Ciprofloxacin,Levofloxacin,Aztreonam,Cefepime,Cefoperazone/Sulbactam,Piperacillin/Tazobactam and colistin were determined using the microbroth dilution method.The whole-genome sequencing analysis was conducted to determine the STs, virulence genes, and antibiotic resistance genes of three CRKp strains.
RESULTS
Whole-genome sequencing revealed that all three CRKp strains belonged to the sequence type (ST) 11 clone and carried a plasmid encoding blaKPC-2. The three strains all possessed the iucABCDiutA virulence cluster, peg-344 gene, and rmpA/rmpA2 genes, defining them as hv-CRKp. Further experiments and whole-genome analysis revealed that a strain of Kp has developed resistance to colistin. The mechanism found to be responsible for the colistin resistance was a deletion mutation of approximately 9000 bp including mgrB gene.
CONCLUSION
This study characterizes the colistin resistance of ST11 clone hv-CRKp during colistin treatment and its rapid evolution within the host.
PubMed: 38849114
DOI: 10.1016/j.jgar.2024.05.021 -
International Journal of Pharmaceutics Jun 2024Delivering novel antimycobacterial agents through the pulmonary route using nanoparticle-based systems shows promise for treating diseases like tuberculosis. However,...
Delivering novel antimycobacterial agents through the pulmonary route using nanoparticle-based systems shows promise for treating diseases like tuberculosis. However, creating dry powder inhaler (DPI) with suitable aerodynamic characteristics while preserving nanostructure integrity and maintaining bioactivity until the active ingredient travels deeply into the lungs is a difficult challenge. We developed DPI formulations containing levofloxacin-loaded solid lipid nanoparticles (SLNs) via spray-drying technique with tailored aerosolization characteristics for effective inhalation therapy. A range of biophysical techniques, including transmission electron microscopy, confocal microscopy, and scanning electron microscopy were used to measure the morphologies and sizes of the spray-dried microparticles that explored both the geometric and aerodynamic properties. Spray drying substantially reduced the particle sizes of the SLNs while preserving their nanostructural integrity and enhancing aerosol dispersion with efficient mucus penetration. Despite a slower uptake rate compared to plain SLNs, the polyethylene glycol modified formulations exhibited enhanced cellular uptake in both A549 and NR8383 cell lines. The percent viability of Mycobacterium bovis had dropped to nearly 0 % by day 5 for both types of SLNs. Interestingly, the levofloxacin-loaded SLNs demonstrated a lower minimum bactericidal concentration (0.25 µg/mL) compared with pure levofloxacin (1 µg/mL), which indicated the formulations have potential as effective treatments for tuberculosis.
PubMed: 38848797
DOI: 10.1016/j.ijpharm.2024.124309 -
The Journal of Antimicrobial... Jun 2024Stenotrophomonas maltophilia is a carbapenem-resistant Gram-negative pathogen increasingly responsible for difficult-to-treat nosocomial infections.
BACKGROUND
Stenotrophomonas maltophilia is a carbapenem-resistant Gram-negative pathogen increasingly responsible for difficult-to-treat nosocomial infections.
OBJECTIVES
To describe the contemporary clinical characteristics and genome epidemiology of patients colonized or infected by S. maltophilia in a multicentre, prospective cohort.
METHODS
All patients with a clinical culture growing S. maltophilia were enrolled at six tertiary hospitals across Japan between April 2019 and March 2022. The clinical characteristics, outcomes, antimicrobial susceptibility and genomic epidemiology of cases with S. maltophilia were investigated.
RESULTS
In total, 78 patients were included representing 34 infection and 44 colonization cases. The median age was 72.5 years (IQR, 61-78), and males accounted for 53 cases (68%). The most common comorbidity was localized solid malignancy (39%). Nearly half of the patients (44%) were immunosuppressed, with antineoplastic chemotherapy accounting for 31%. The respiratory tract was the most common site of colonization (86%), whereas bacteraemia accounted for most infection cases (56%). The 30 day all-cause mortality rate was 21%, which was significantly higher in infection cases than colonization cases (35% versus 9%; adjusted HR, 3.81; 95% CI, 1.22-11.96). Susceptibility rates to ceftazidime, levofloxacin, minocycline and sulfamethoxazole/trimethoprim were 14%, 65%, 87% and 100%, respectively. The percentage of infection ranged from 13% in the unclassified group to 86% in genomic group 6A. The percentage of non-susceptibility to ceftazidime ranged from 33% in genomic group C to 100% in genomic groups 6 and 7 and genomic group geniculate.
CONCLUSIONS
In this contemporary multicentre cohort, S. maltophilia primarily colonized the respiratory tract, whereas patients with bacteraemia had the highest the mortality from this pathogen. Sulfamethoxazole/trimethoprim remained consistently active, but susceptibility to levofloxacin was relatively low. The proportions of cases representing infection and susceptibility to ceftazidime differed significantly based on genomic groups.
PubMed: 38842502
DOI: 10.1093/jac/dkae168 -
Journal of the Canadian Association of... Jun 2024Updated 2016 consensus guidelines recommend treatment for 14 days with concomitant therapy (proton-pump inhibitor (PPI)-amoxicillin-metronidazole-clarithromycin (PAMC)...
BACKGROUND
Updated 2016 consensus guidelines recommend treatment for 14 days with concomitant therapy (proton-pump inhibitor (PPI)-amoxicillin-metronidazole-clarithromycin (PAMC) or bismuth-based quadruple therapy (PPI-bismuth-metronidazole-tetracycline, PBMT)) as first line, PBMT or PPI-amoxicillin-levofloxacin (PAL) as second or third line, and PPI-amoxicillin-rifabutin (PAR) as fourth line for 10 days.
OBJECTIVES
This was a retrospective cohort study to describe and compare the efficacy of anti- treatment regimens over the periods 2007-2015 and 2016-2021 as well as antibiotic resistance.
METHODS
A modified intention-to-treat (mITT) analysis was used to analyze the success rate of therapies. mITT includes all patients who were prescribed treatment and had at least one follow-up test-of-cure. This included patients who could not complete treatment or were non-adherent with treatment. Risk factors for treatment failures were analyzed by univariate and multivariate logistic regression. Resistance testing was done in a small subset of patients.
RESULTS
-positive patients who received treatment in Edmonton, Alberta were included in a mITT analysis: 334/387(86%) from 2007 to 2015 and 193/199 (97%) from 2016 to 2021. During 2016-2021, 78% (150/193) of patients underwent cumulative guideline-based treatment with a successful cure in 80% (120/150) of patients. In those who were newly diagnosed, the cure rate was 88% (52/59) versus those with previous treatment failure 75% (68/91) ( < 0.05, risk difference [RD] 14%, 95% confidence interval [CI] 1.7-26.3%). The most effective first-line regimens were PAMC for 14 days (87% [45/52]) in 2016-2021 and sequential therapy in 2007-2015 (83% [66/80]) ( = 0.535, RD 4%, 95% CI -8.5-16.5%). When other treatments failed, success with PAR was 50% (2/4) from 2007 to 2015 and 57% (21/37) from 2016 to 2021. Recent (2016-2021) resistance rates to clarithromycin and metronidazole are high at 78% (50/64) and 56% (29/52), respectively. From 2007 to 2015, clarithromycin and metronidazole resistance rates were 80% (36/45) and 83% (38/46), respectively. Levofloxacin resistance increased significantly from 2007-2015 to 2016-2021 (28% [13/46] to 61% [35/57], < 0.05, RD 33%, 95% CI 11.6-54.4%).
CONCLUSIONS
Algorithmic treatment with PAMC first line followed by PBMT, PAL, and PAR cures in 88% of newly diagnosed patients. PAR therapy shows suboptimal cure rates (50-57% success) but can be considered as third instead of fourth line given increasing levofloxacin resistance rates. Antibiotic resistance in is common to clarithromycin, metronidazole, and levofloxacin and frequently accounts for treatment failures.
PubMed: 38841147
DOI: 10.1093/jcag/gwad051 -
Journal of Colloid and Interface Science May 2024This study reports the development of a photocatalytic electrochemical aptasensor for the purpose of detecting chloramphenicol (CAP) antibiotic residues in water by...
This study reports the development of a photocatalytic electrochemical aptasensor for the purpose of detecting chloramphenicol (CAP) antibiotic residues in water by utilizing SYBR Green I (SG) and chemically exfoliated MoS (ce-MoS) as synergistically signal-amplification platforms. The Au nanoparticles (AuNPs) were electrodeposited onto the surface of an indium tin oxide (ITO) electrode. After that, the thiolate-modified cDNA, also known as capture DNA, was combined with the aptamer. Subsequently, photosensitized SG molecules and ce-MoS nanomaterial were inserted into the groove of the resultant double-stranded DNA (dsDNA). The activation of the photocatalytic process upon exposure to light resulted in the generation of singlet oxygen. The singlet oxygen effectively split the dsDNA, resulting in significant enhancement in the current of [Fe(CN)]. When the CAP was present, both SG molecules and ce-MoS broke away from the dsDNA, which turned off the photosensitization response, leading to significant reduction in the current of [Fe(CN)]. Under the optimal conditions, the aptasensor exhibited a linear relationship between the current of [Fe(CN)] with logarithmic concentrations of CAP from 20 to 1000 nM, with a detection of limit (3σ) of 3.391 nM. The aptasensor also demonstrated good selectivity towards CAP in the presence of interfering antibiotics, such as tetracycline, streptomycin, levofloxacin, ciprofloxacin, and sulfadimethoxine. Additionally, the results obtained from the analysis of natural water samples using the proposed aptasensor were consistent with the findings acquired through the use of a liquid chromatograph-mass spectrometer. Therefore, with its simplicity and high selectivity, this aptasensor can potentially detect alternative antibiotics in environmental water samples by replacing the aptamers based on photosensitization.
PubMed: 38838631
DOI: 10.1016/j.jcis.2024.05.109 -
Scientific Reports Jun 2024This study investigates quercetin complexes as potential synergistic agents against the important respiratory pathogen Streptococcus pneumoniae. Six quercetin complexes...
This study investigates quercetin complexes as potential synergistic agents against the important respiratory pathogen Streptococcus pneumoniae. Six quercetin complexes (QCX1-6) were synthesized by reacting quercetin with various metal salts and boronic acids and characterized using FTIR spectroscopy. Their antibacterial activity alone and in synergism with antibiotics was evaluated against S. pneumoniae ATCC 49619 using disc diffusion screening, broth microdilution MIC determination, and checkerboard assays. Complexes QCX-3 and QCX-4 demonstrated synergy when combined with levofloxacin via fractional inhibitory concentration indices ≤ 0.5 as confirmed by time-kill kinetics. Molecular docking elucidated interactions of these combinations with virulence enzymes sortase A and sialidase. A biofilm inhibition assay found the synergistic combinations more potently reduced biofilm formation versus monotherapy. Additionally, gene-gene interaction networks, biological activity predictions and in-silico toxicity profiling provided insights into potential mechanisms of action and safety.
Topics: Streptococcus pneumoniae; Quercetin; Anti-Bacterial Agents; Biofilms; Molecular Docking Simulation; Microbial Sensitivity Tests; Drug Synergism; Bacterial Proteins; Cysteine Endopeptidases; Aminoacyltransferases; Neuraminidase
PubMed: 38834612
DOI: 10.1038/s41598-024-62782-w -
Clinical Infectious Diseases : An... Jun 2024In 2019, WHO called for operational research on all-oral shortened regimens for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We report safety and...
BACKGROUND
In 2019, WHO called for operational research on all-oral shortened regimens for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We report safety and effectiveness of three nine-month all-oral regimens containing bedaquiline (Bdq), linezolid (Lzd), and levofloxacin (Lfx) and reinforced with cycloserine (Cs) and clofazimine (Cfz), delamanid (Dlm) and pyrazinamide (Z), or Dlm and Cfz.
METHODS
We conducted a prospective cohort study of patients initiating treatment for pulmonary MDR/RR-TB under operational research conditions at public health facilities in Kazakhstan. Participants were screened monthly for adverse events. Participants with baseline resistance were excluded from the study and treated with a longer regimen. We analyzed clinically relevant adverse events of special interest in all participants and sputum culture conversion and end-of-treatment outcomes among individuals who were not excluded.
RESULTS
Of 510 participants, 41% were women, median age was 37 years (interquartile range: 28-49), 18% had a body mass index <18·5 kg/m2, and 51% had cavitary disease. Three hundred and ninety-nine (78%) initiated Bdq-Lzd-Lfx-Cs-Cfz, 83 (16%) started Bdq-Lzd-Lfx-Dlm-Z, and 28 (5%) initiated Bdq-Lzd-Lfx-Dlm-Cfz. Fifty-eight individuals (11%) were excluded from the study, most commonly due to identification of baseline drug resistance (n = 52; 90%). Among the remaining 452 participants, treatment success frequencies were 92% (95% confidence interval [CI]: 89 to 95), 89% (95%CI: 80 to 94), and 100% (95%CI: 86 to 100) for regimens with Cs/Cfz, Dlm/Z, and Dlm/Cfz respectively. Clinically-relevant adverse events of special interest were uncommon.
CONCLUSION
All regimens demonstrated excellent safety and effectiveness, expanding the potential treatment options for patients, providers, and programs.
PubMed: 38833593
DOI: 10.1093/cid/ciae305