Analysis of Serial Multidrug-Resistant Tuberculosis Strains Causing Treatment Failure and Within-Host Evolution by Whole-Genome Sequencing

The cure rate of multidrug-resistant tuberculosis (MDR-TB) is relatively low in China. The reasons for the treatment failure and within-host evolution during treatment have not been sufficiently studied. All MDR-TB patients receiving standard treatment from January 2014 to September 2016 at a designated TB Hospital in Zhejiang Province were retrospectively included and grouped according to their known treatment outcome. Clinical information was collected. Baseline strains of all patients and serial strains of treatment-failure patients were revived. Drug susceptibility tests (DSTs) of 14 drugs and single nucleotide polymorphism (SNP) analysis based on whole-genome sequencing (WGS) were performed. The genetic distance and within-host evolution were investigated based on SNPs. In total, 20 treatment failure patients and 74 patients who succeeded in treatment were included. The number of effective drugs for patients who failed treatment was no more than three. Eighteen (90.0%) treatment-failure patients were characterized by a continuous infection of the primary strain, of which 14 patients (77.8%) developed phenotypic or genotypic acquired drug resistance under ineffective treatment. Acquired resistance to amikacin and moxifloxacin (2.0 mg/ml) was detected most frequently, in 5 and 4 patients, respectively. The insufficient number of effective drugs in the combined treatment regimen was the main reason for MDR-TB treatment failure. The study emphasizes the importance of DST for second-line drugs when implementing the second-line drug regimen in MDR-TB patients. For patients with risk factors for MDR-TB, DST of second-line antituberculosis drugs should be performed at initiation of treatment. Second-line drugs should be selected based on the results of DST to avoid acquired resistance. WGS detects low-frequency resistance mutations and heterogeneous resistance with high sensitivity, which is of great significance for guiding clinical treatment and preventing acquired resistance.IMPORTANCE Few studies have focused on the reasons for the low cure rate of multidrug-resistant tuberculosis in China and within-host evolution during treatment, which is of great significance for improving clinical treatment regimens. Acquired resistance events were common during the ineffective treatment, among which resistance to amikacin and high-level moxifloxacin were the most common. The main reason for the treatment failure of MDR-TB patients was insufficient effective drugs, which may lead to higher levels of drug resistance in MDR-TB strains. Therefore, the study emphasizes the importance of DST in the development of second-line treatment regimen when there is a risk of MDR. By performing whole-genome sequencing of serial strains from patients with treatment failure, we found that WGS can detect low-frequency resistance mutations and heterogeneous resistance with high sensitivity. It is thus recommended to conduct drug susceptibility tests at the beginning of treatment and repeat the DST when the sputum bacteria remain positive.

Molecular and Biochemical Basis of Fluoroquinolones-Induced Phototoxicity-The Study of Antioxidant System in Human Melanocytes Exposed to UV-A Radiation

Phototoxicity of fluoroquinolones is connected with oxidative stress induction. Lomefloxacin (8-halogenated derivative) is considered the most phototoxic fluoroquinolone and moxifloxacin (8-methoxy derivative) the least. Melanin pigment may protect cells from oxidative damage. On the other hand, fluoroquinolone–melanin binding may lead to accumulation of drugs and increase their toxicity to skin. The study aimed to examine the antioxidant defense system status in normal melanocytes treated with lomefloxacin and moxifloxacin and exposed to UV-A radiation. The obtained results demonstrated that UV-A radiation enhanced only the lomefloxacin-induced cytotoxic effect in tested cells. It was found that fluoroquinolones alone and with UV-A radiation decreased superoxide dismutase (SOD) activity and SOD1 expression. UV-A radiation enhanced the impact of moxifloxacin on hydrogen peroxide-scavenging enzymes. In turn, lomefloxacin alone increased the activity and the expression of catalase (CAT) and glutathione peroxidase (GPx), whereas UV-A radiation significantly modified the effects of drugs on these enzymes. Taken together, both analyzed fluoroquinolones induced oxidative stress in melanocytes, however, the molecular and biochemical studies indicated the miscellaneous mechanisms for the tested drugs. The variability in phototoxic potential between lomefloxacin and moxifloxacin may result from different effects on the antioxidant enzymes.

Thermochromic Hydrogel-Functionalized Textiles for Synchronous Visual Monitoring of On-Demand In Vitro Drug Release

In vitro drug release systems have recently received tremendous attention because they allow noninvasive, convenient, and prolonged administration of pharmacological agents. On-demand epidermal drug release systems can improve treatment efficiency, prevent multidrug resistance, and minimize drug toxicity to healthy cells. In addition, real-time monitoring of drug content is also essential for guiding the determination of drug dosage and replacing drug carriers in time. Therefore, it is important to integrate the above properties in one ideal epidermal patch. Herein, photonic crystals (PCs) based on Fe₃O₄@C nanoparticles were introduced into drug-loaded poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-AAc)) hydrogel-functionalized textiles. Drug loading and release depended on the expansion and contraction of the hydrogels. The lower critical solution temperature (LCST) of the hydrogels was adjusted to 40 °C, which is higher than the skin temperature, by varying the content of hydrophilic comonomer acrylic acid (AAc) to store the drug at room temperature, and on-demand release was achieved by mild thermal stimulation. Moreover, the lattice spacing (d) of PCs varied with the expansion and contraction of the hydrogels, which can cause the color of P(NIPAM-AAc) hydrogel-functionalized textiles to change. These synchronous thermoresponsive chromic drug uptake and release behaviors provided an effective method for visual and real-time monitoring of drug content. Furthermore, in view of the poor mechanical properties of hydrogel wound dressings, textile matrices were composited to prevent holistic breaking during the stretching process. Biological experiments proved that the drug-loaded P(NIPAM-AAc) hydrogel-functionalized textiles had good antibacterial properties and wound-healing effects.

Antibacterial activity of a DNA topoisomerase I inhibitor versus fluoroquinolones in Streptococcus pneumoniae

The DNA topoisomerase complement of Streptococcus pneumoniae is constituted by two type II enzymes (topoisomerase IV and gyrase), and a single type I enzyme (topoisomerase I). These enzymes maintain the DNA topology, which is essential for replication and transcription. While fluoroquinolones target the type II enzymes, seconeolitsine, a new antimicrobial agent, targets topoisomerase I. We compared for the first time the in vitro effect of inhibition of topoisomerase I by seconeolitsine and of the type II topoisomerases by the fluoroquinolones levofloxacin and moxifloxacin. We used three isogenic non-encapsulated strains and five non-vaccine serotypes isolates belonging to two circulating pneumococcal clones, ST63⁸ (2 strains) and ST156^9V (3 strains). Each group contained strains with diverse susceptibility to fluoroquinolones. Minimal inhibitory concentrations, killing curves and postantibiotic effects were determined. Seconeolitsine demonstrated the fastest and highest bactericidal activity against planktonic bacteria and biofilms. When fluoroquinolone-susceptible planktonic bacteria were considered, seconeolitsine induced postantibiotic effects (1.00−1.87 h) similar than levofloxacin (1.00−2.22 h), but longer than moxifloxacin (0.39−1.71 h). The same effect was observed in sessile bacteria forming biofilms. Seconeolitsine induced postantibiotic effects (0.84−2.31 h) that were similar to those of levofloxacin (0.99−3.32 h) but longer than those of moxifloxacin (0.89−1.91 h). The greatest effect was observed in the viability and adherence of bacteria in the postantibiotic phase. Seconeolitsine greatly reduced the thickness of the biofilms formed in comparison with fluoroquinolones: 2.91 ± 0.43 μm (seconeolitsine), 7.18 ± 0.58 μm (levofloxacin), 17.08 ± 1.02 μm (moxifloxacin). When fluoroquinolone-resistant bacteria were considered, postantibiotic effects induced by levofloxacin and moxifloxacin, but not by seconeolitsine, were shorter, decreasing up to 5-fold (levofloxacin) or 2-fold (moxifloxacin) in planktonic cells, and up to 1.7 (levofloxacin) or 1.4-fold (moxifloxacin) during biofilm formation. Therefore, topoisomerase I inhibitors could be an alternative for the treatment of pneumococcal diseases, including those caused by fluoroquinolone-resistant isolates.

Lefamulin vs moxifloxacin for community-acquired bacterial pneumonia

Lefamulin is a novel pleuromutilin antibiotic with potent in vitro activity against key community-acquired bacterial pneumonia (CABP) pathogens. However, the clinical efficacy and safety of lefamulin for treating CABP remains unclear.An integrated analysis of 2 phase III trials investigating the clinical efficacy and safety of lefamulin vs moxifloxacin in the treatment of CABP was conducted.A total of 1289 patients (lefamulin group: 646 and moxifloxacin group: 643) were included in this analysis. The early clinical response rate was 89.3% and 90.5% among lefamulin and moxifloxacin group, respectively. Lefamulin was noninferior to moxifloxacin (89.3% vs 90.5%, RR: 0.99, 95% CI: 0.95-1.02, I = 0%). In terms of clinical response at test of cure, no significant difference was observed between the lefamulin and moxifloxacin groups (for modified intention to treat population, RR: 0.98, 95% CI: 0.94-1.02, I = 0%; for clinically evaluable population, RR: 0.96, 95% CI: 0.93-1.00, I = 0%). In the subgroup analysis, the early clinical response rate at early clinical assessment and clinical response rate at test of cure of lefamulin was similar to that of moxifloxacin across different subgpopulations and all baseline CABP pathogens. Lefamulin was associated with a similar risk of adverse events as moxifloxacin.Clinical efficacy and tolerability for lefamulin in the treatment of CABP were similar to those for moxifloxacin.

Efficacy of Moxifloxacin against Mycobacterium abscessus in Zebrafish Model in vivo

OBJECTIVE

Moxifloxacin (MFX) shows good in vitro activity against Mycobacterium abscessus and can be a possible antibiotic therapy to treat M. abscessus infection; however, other studies have shown a lower or no activity. We aimed to evaluate MFX activity against M. abscessus using zebrafish (ZF) model in vivo.

METHODS

A formulation of M. abscessus labeled with CM-Dil was micro-injected into ZF. Survival curves were determined by recording dead ZF every day. ZF were lysed, and colony-forming units (CFUs) were enumerated. Bacteria dissemination and fluorescence intensity in ZF were analyzed. Inhibition rates of MFX and azithromycin (AZM, positive control) were determined and compared.

RESULTS

Significantly increased survival rate was observed with different AZM concentrations. However, increasing MFX concentration did not result in a significant decrease in ZF survival curve. No significant differences in bacterial burdens by CFU loads were observed between AZM and MFX groups at various concentrations. Bacterial fluorescence intensity in ZF was significantly correlated with AZM concentration. However, with increasing MFX concentration, fluorescence intensity decreased slightly when observed under fluorescence microscope. Transferring rates at various concentrations were comparable between the MFX and AZM groups, with no significant difference.

CONCLUSION

MFX showed limited efficacy against M . abscessus in vivo using ZF model. Its activity in vivo needs to be confirmed.

Moxifloxacin interacts with lipid bilayer, causing dramatic changes in its structure and phase transitions

Most drugs besides their intended activity, express undesired side effects, including those with the engagement of cell membrane. Previously, such undesired nonspecific effects on the membrane have been shown for a number of widely used nonsteroidal anti-inflammatory drugs. In this paper, we study the mechanism of interaction between moxifloxacin (Mox), antibacterial drug of broad specificity, with lipid bilayer of the liposomes of various compositions as a model of cell membrane using a combination of spectroscopy methods, including ATR-FTIR spectroscopy, circular dichroism, UV and fluorescence spectroscopy. The fine structure of the moxifloxacin-liposome complex, localization of the drug in bilayer and the main sites of Mox interaction with lipid membrane were determined. Lipid composition of the liposome plays a key role in the interaction with moxifloxacin, drastically affecting the loading efficiency, strength and character of drug binding, lipid phase segregation and phase transition parameters. In case of anionic liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and cardiolipin (CL^2-) the electrostatic interaction of negatively charged nitrogen in heterocycle moiety of moxifloxacin with cardiolipin phosphate groups is a crucial factor for stable complex formation. The study of moxifloxacin-liposome complex behavior at phase transition in bilayer by DSC method revealed that in DPPC/CL^2- liposomes system two microphases with different content of CL^2- coexist and Mox interacts with both of these microphases resulting in the formation of two types of complexes with different structure and phase transition temperature. This binding stabilized the gel-state of the lipid bilayer with increasing the phase transition temperature Tm up to 3-5 °C. A different situation is observed for neutral DPPC liposomes: drug interaction with bilayer results in defects formation and a fluidization effect in lipid bilayer, resulted to decrease the Tm value by 2-4 °C. Moxifloxacin is not firmly binding in the membrane of DPPC and drug releases rapidly.

Fluoroquinolones suppress gluconeogenesis by inhibiting fructose 1,6-bisphosphatase in primary monkey hepatocytes

Dysglycemia is one of the most serious adverse events associated with the clinical use of certain fluoroquinolones. The purpose of this study was to investigate the effects of the representative fluoroquinolones moxifloxacin and gatifloxacin on hepatic gluconeogenesis using primary monkey hepatocytes. Glucose production was induced after the cells were incubated for 4 h with 10 mM sodium lactate and 1 mM sodium pyruvate as gluconeogenic substrates. Under these conditions, moxifloxacin and gatifloxacin dose-dependently suppressed gluconeogenesis at concentrations of 100 μM or higher. Transcriptome analysis of rate-limiting enzymes involved in hepatic gluconeogenesis revealed that moxifloxacin and gatifloxacin at a concentration of 1000 μM did not affect the expression of key gluconeogenic enzymes such as phosphoenolpyruvate carboxykinase, glucose 6-phosphatase, and fructose 1,6-bisphosphatase. Furthermore, metabolome analysis, in vitro glucose production assay using additional gluconeogenic substrates, and fructose 1,6-bisphosphatase assay using the cell extracts showed that fluoroquinolones enzymatically suppressed hepatic gluconeogenesis by inhibiting fructose 1,6-bisphosphatase. These inhibitory effects may involve in the clinically relevant dysglycemia associated with fluoroquinolones in human.

The emergence of Clostridium difficile ribotypes 027 and 176 with a predominance of the Clostridium difficile ribotype 001 recognized in Slovakia following the European standardized Clostridium difficile infection surveillance of 2016

AIM

To obtain standardized epidemiological data for Clostridium difficile infection (CDI) in Slovakia.

METHODS

Between October and December 2016, 36 hospitals in Slovakia used the European Centre for Disease Prevention and Control (ECDC) Clostridium difficile infection (CDI) surveillance protocol.

RESULTS

The overall mean CDI incidence density was 2.8 (95% confidence interval 1.9-3.9) cases per 10 000 patient-days. Of 332 CDI cases, 273 (84.9%) were healthcare-associated, 45 (15.1%) were community-associated, and 14 (4.2%) were cases of recurrent CDI. A complicated course of CDI was reported in 14.8% of cases (n=51). CDI outcome data were available for 95.5% of cases (n=317). Of the 35 patients (11.1%) who died, 34 did so within 30 days after their CDI diagnosis. Of the 78 isolates obtained from 12 hospitals, 46 belonged to PCR ribotype 001 (59.0%; 11 hospitals) and 23 belonged to ribotype 176 (29.5%; six hospitals). A total of 73 isolates (93.6%) showed reduced susceptibility to moxifloxacin (ribotypes 001 and 176; p< 0.01). A reduced susceptibility to metronidazole was observed in 13 isolates that subsequently proved to be metronidazole-susceptible when, after thawing, they were retested using the agar dilution method. No reduced susceptibility to vancomycin was found.

CONCLUSIONS

These results show the emergence of C. difficile ribotypes 027 and 176 with a predominance of ribotype 001 in Slovakia in 2016. Given that an almost homogeneous reduced susceptibility to moxifloxacin was detected in C. difficile isolates, this stresses the importance of reducing fluoroquinolone prescriptions in Slovak healthcare settings.

Antibiotic Resistance, Biofilm Formation, and Intracellular Survival As Possible Determinants of Persistent or Recurrent Infections by Staphylococcus aureus in a Vietnamese Tertiary Hospital: Focus on Bacterial Response to Moxifloxacin

Resistance is notoriously high in Asia but may not entirely explain therapeutic failures. Specific modes of bacterial life, such as biofilm or intracellular survival, may also contribute to the persistent and/or recurrent character of infections. Most Staphylococcus aureus isolates form biofilm and many survive and even thrive intracellularly. We collected 36 nonduplicate S. aureus isolates (including 18 methicillin-resistant S. aureus) from patients with clinical evidence of persistent or recurrent infections in a large tertiary Vietnamese hospital. We examined their antibiotic resistance profile (minimal inhibitory concentration determination) and clonal relatedness (spa and agr typing, pulsed field gel electrophoresis profiles). We then assessed the activity of moxifloxacin in both biofilms and infected phagocytes (moxifloxacin previously proved to be one of the most active antibiotics against reference strains in these models). spa-types t189 and t437 and agr group I were the most frequent. Among the 36 isolates, 30 were multidrug resistant but 30 were recovered from patients having received an active drug. All tested isolates produced biofilm and survived inside phagocytes. At its human C_max, moxifloxacin was inactive on biofilms made by moxifloxacin-susceptible as well as moxifloxacin-resistant isolates. It caused only a modest intracellular colony-forming unit decrease against moxifloxacin-susceptible isolates and was inactive against those resistant to moxifloxacin. While our data confirm for this collection the high resistance levels and prevalence of endemic spa- or agr- types in Asia, they show that tolerance in both biofilm and phagocytes are correlated and markedly limit moxifloxacin activity, which goes in line with the suggested role of these modes of life in persistence or recurrence of infections.

Effect of Cefiderocol, a Siderophore Cephalosporin, on QT/QTc Interval in Healthy Adult Subjects

PURPOSE

Cefiderocol is a novel siderophore cephalosporin with potent activity against gram-negative bacteria, including multidrug-resistant strains. This Phase I study was conducted to assess the tolerability of single-ascending doses of cefiderocol (part 1) and the effect of cefiderocol on cardiac repolarization, assessed using the electrocardiographic corrected QT interval (QTcF) and other ECG parameters (part 2), in healthy adult subjects.

METHODS

Part 1 was a randomized, double-blind, placebo-controlled, single-ascending dose study in healthy adult male and female subjects. Part 2 was a 4-period crossover study in which subjects received a single 2-g dose of cefiderocol (therapeutic dose), a single 4-g dose of cefiderocol (supratherapeutic dose), or saline (placebo), each infused over 3 hours, and a single oral 400-mg dose of moxifloxacin. In each treatment period, continuous cardiac monitoring was used to assess the effects of cefiderocol on ECG parameters. The QT interval corrected using the Fridericia formula (QTcF) was the primary ECG parameter; the time-matched placebo- and baseline-adjusted (dd)-QTcF interval was the primary end point. The plasma pharmacokinetic properties of cefiderocol were calculated on the basis of concentration-time profiles in all evaluable subjects.

FINDINGS

All point estimates for the ddQTcF interval were <5 ms and the upper bound of the 90% CIs were <10 ms at each timepoint after the initiation of the cefiderocol 3-hour infusion. Concentration-effect modeling showed a slightly negative slope and predicted modestly negative values of the ddQTcF interval at the Cmax of cefiderocol. Both doses of cefiderocol were well tolerated. All adverse events were mild in severity, with no deaths or serious adverse events reported.

IMPLICATIONS

Overall, therapeutic and supratherapeutic doses of cefiderocol had no apparent clinically significant effect on the QTcF.

Using Mycobacterium tuberculosis Single-Nucleotide Polymorphisms To Predict Fluoroquinolone Treatment Response

Clinical phenotypic fluoroquinolone susceptibility testing of Mycobacterium tuberculosis is currently based on M. tuberculosis growth at a single critical concentration, which provides limited information for a nuanced clinical response. We propose using specific resistance-conferring M. tuberculosis mutations in gyrA together with population pharmacokinetic and pharmacodynamic modeling as a novel tool to better inform fluoroquinolone treatment decisions. We sequenced the gyrA resistance-determining region of 138 clinical M. tuberculosis isolates collected from India, Moldova, Philippines, and South Africa and then determined each strain's MIC against ofloxacin, moxifloxacin, levofloxacin, and gatifloxacin. Strains with specific gyrA single-nucleotide polymorphisms (SNPs) were grouped into high or low drug-specific resistance categories based on their empirically measured MICs. Published population pharmacokinetic models were then used to explore the pharmacokinetics and pharmacodynamics of each fluoroquinolone relative to the empirical MIC distribution for each resistance category to make predictions about the likelihood of patients achieving defined therapeutic targets. In patients infected with M. tuberculosis isolates containing SNPs associated with a fluoroquinolone-specific low-level increase in MIC, models suggest increased fluoroquinolone dosing improved the probability of achieving therapeutic targets for gatifloxacin and moxifloxacin but not for levofloxacin and ofloxacin. In contrast, among patients with isolates harboring SNPs associated with a high-level increase in MIC, increased dosing of levofloxacin, moxifloxacin, gatifloxacin, or ofloxacin did not meaningfully improve the probability of therapeutic target attainment. We demonstrated that quantifiable fluoroquinolone drug resistance phenotypes could be predicted from rapidly detectable gyrA SNPs and used to support dosing decisions based on the likelihood of patients reaching therapeutic targets. Our findings provide further supporting evidence for the moxifloxacin clinical breakpoint recently established by the World Health Organization.

Moxifloxacin resistance and genotyping of Mycobacterium avium and Mycobacterium intracellulare isolates in Japan

BACKGROUND

Although fluoroquinolones are considered as alternative therapies of pulmonary Mycobacterium avium complex (MAC) disease, the association between fluoroquinolone resistance and MAC genotypes in clinical isolates from individuals not previously treated for MAC infection is not fully clear.

METHODS

Totals of 154 M. avium isolates and 35 Mycobacterium intracellulare isolates were obtained from treatment-naïve patients with pulmonary MAC disease at the diagnosis of MAC infection at 8 hospitals in Japan. Their susceptibilities of moxifloxacin were determined by broth microdilution methods. Moxifloxacin-resistant isolates were examined for mutations of gyrA and gyrB. Variable numbers of tandem repeats (VNTR) assay was performed using 15 M. avium VNTR loci and 16 M. intracellulare VNTR loci.

RESULTS

Moxifloxacin susceptibility was categorized as resistant and intermediate for 6.5% and 16.9%, respectively, of M. avium isolates and 8.6% and 17.1% of M. intracellulare isolates. Although the isolates of both species had amino acid substitutions of Thr 96 and Thr 522 at the sites corresponding to Ser 95 in the M. tuberculosis GyrA and Gly 520 in the M. tuberculosis GyrB, respectively, these substitutions were observed irrespective of susceptibility and did not confer resistance. The VNTR assays showed revealed three clusters among M. avium isolates and two clusters among M. intracellulare isolates. No significant differences in moxifloxacin resistance were observed among these clusters.

CONCLUSIONS

Although resistance or intermediate resistance to moxifloxacin was observed in approximately one-fourth of M. avium and M. intracellulare isolates, this resistance was not associated with mutations in gyrA and gyrB or with VNTR genotypes.

Moxifloxacin-Ester derivatives: Synthesis, characterization and pharmacological evaluation

It is known that resistance of bacteria is one of the major issues in drug treatment. To cope this issue, it is required to synthesize new analogues which contest against mutated bacteria. This research study included synthesis of several derivatives of moxifloxacin by adding different phenol and alkyl halide at third position of carboxylic group with esterification reaction and the structures of synthesized derivatives were characterized by spectroscopic techniques i.e. ¹H NMR, FT-IR and mass-spectrometry. In continuation, antimicrobial activities of the analogues were also evaluated against number of Gram-positive, Gram-negative bacteria and fungi. The experimental results of novel derivatives exhibit significant antibacterial and antifungal profile in which so many synthesized derivatives influenced a similar and enhanced activity against selected microbes that were S. typhi, P. mirabilis, P. aeruginosa, S. flexneri, B. subtilis as compared to the moxifloxacin. Moreover, few innovative derivatives were also produced better anti-fungal activity against F. solani and T. rubrum. Furthermore, the enzymatic activity of all analogues has been analyzed against urease and carbonic anhydrase and concluded that C2 was selected inhibitor of urease enzyme.

Synthesis, characterization, antimicrobial and enzyme inhibitory studies of moxifloxacin with aromatic carboxylic acids

A series of carboxamide derivatives of moxifloxacin has been synthesized. The synthesized derivatives has been characterization by using spectroscopic techniques such as UV-Vis, IR, H1NMR and Mass spectra, which suggested that incoming group has occupied azabicylo groups of selected moxifloxacin at 7th position. Antimicrobial screening has been systematically carried out against various gram-positive, Gram-negatives and fungi in comparison with parent drug. Enzymatic assay were also performed. The results obtained were statistically analyzed by one way ANOVA. The antimicrobial results reveals that the synthesized derivative of moxifloxacin possess good activities against B. subtilis, F. solani, T. rubrum and P. aeruginosa concluding that derivatives are more potent antimicrobial agents as compared to parent drug. While compound B1 solely possess mild enzymatic activity against urease whereas, no other compounds is active against both urease and carbonic anhydrase.

Extracellular vesicles deliver Mycobacterium RNA to promote host immunity and bacterial killing

Extracellular vesicles (EVs) have been shown to carry microbial components and function in the host defense against infections. In this study, we demonstrate that Mycobacterium tuberculosis (M.tb) RNA is delivered into macrophage-derived EVs through an M.tb SecA2-dependent pathway and that EVs released from M.tb-infected macrophages stimulate a host RIG-I/MAVS/TBK1/IRF3 RNA sensing pathway, leading to type I interferon production in recipient cells. These EVs also promote, in a RIG-I/MAVS-dependent manner, the maturation of M.tb-containing phagosomes through a noncanonical LC3 pathway, leading to increased bacterial killing. Moreover, treatment of M.tb-infected macrophages or mice with a combination of moxifloxacin and EVs, isolated from M.tb-infected macrophages, significantly lowered bacterial burden relative to either treatment alone. We hypothesize that EVs, which are preferentially removed by macrophages in vivo, can be combined with effective antibiotics as a novel approach to treat drug-resistant TB.

Core-sheath micro/nano fiber membrane with antibacterial and osteogenic dual functions as biomimetic artificial periosteum for bone regeneration applications

The traditional Chinese medicine icariin (ICA) and broad-spectrum antibacterial drug moxifloxacin hydrochloride (MOX) were introduced into a polycaprolactone core and gelatin shell, respectively, to develop osteogenic and antibacterial biomimetic periosteum by coaxial electrospinning. The physical properties, drug release, degradation, antibacterial property, in vitro and in vivo osteogenesis performances were investigated. Results demonstrated that stepwise and controlled drug release profiles were achieved based on the core-shell configuration and disparate degradation rate of PCL and gelatin. Only 20% ICA was released from this dual drug-loaded membrane after 1 month while the release of MOX was almost completed. Moreover, clear in vitro antibacterial effect and enhancement in osteogenic marker expressions including osteocalcin, type-I collagen expression, and calcium deposition were observed. Notably, the dual drug-loaded membrane displayed fascinating properties contributing to in vivo bone formation in terms of quality and quantity in a rabbit radius defect model.

Transformation Morphisms and Time-to-Extinction Analysis That Map Therapy Duration From Preclinical Models to Patients With Tuberculosis: Translating From Apples to Oranges

Background

A major challenge in medicine is translation of preclinical model findings to humans, especially therapy duration. One major example is recent shorter-duration therapy regimen failures in tuberculosis.

Methods

We used set theory mapping to develop a computational/modeling framework to map the time it takes to extinguish the Mycobacterium tuberculosis population on chemotherapy from multiple hollow fiber system model of tuberculosis (HFS-TB) experiments to that observed in patients. The predictive accuracy of the derived translation transformations was then tested using data from 108 HFS-TB Rapid Evaluation of Moxifloxacin in Tuberculosis (REMoxTB) units, including 756 colony-forming units (CFU)/mL. Derived transformations, and Latin hypercube sampling-guided simulations were used to predict cure and relapse after 4 and 6 months of therapy. Outcomes were compared to observations, in 1932 patients in the REMoxTB clinical trial.

Results

HFS-TB serial bacillary burden and serial sputum data in the derivation dataset formed a structure-preserving map. Bactericidal effect was mapped with a single step transformation, while the sterilizing effect was mapped with a 3-step transformation function. Using the HFS-TB REMoxTB data, we accurately predicted the proportion of patients cured in the 4-month REMoxTB clinical trial. Model-predicted vs clinical trial observations were (i) the ethambutol arm (77.0% [95% confidence interval {CI}, 74.4%-79.6%] vs 77.7% [95% CI, 74.3%-80.9%]) and (ii) the isoniazid arm (76.4% [95% CI, 73.9%-79.0%] vs 79.5% [95% CI, 76.1%-82.5%]).

Conclusions

We developed a method to translate duration of therapy outcomes from preclinical models to tuberculosis patients.

Mutations in ParC and GyrA of moxifloxacin-resistant and susceptible Mycoplasma genitalium strains

Macrolide or fluoroquinolone-resistant Mycoplasma genitalium is spreading worldwide. We aimed to determine the influence of single nucleotide polymorphisms (SNPs) in the quinolone resistance determining regions (QRDR) of parC and gyrA in cultured M. genitalium strains. In addition, we examined the prevalence of macrolide- and fluoroquinolone resistance mediating mutations in specimens collected from Japanese male patients with urethritis in two time-periods between 2005–2009 and 2010–2017, respectively, by sequencing the QRDR of parC and gyrA and domain V of the 23S rRNA gene. The minimum inhibitory concentrations (MIC) of moxifloxacin, sitafloxacin, ciprofloxacin, levofloxacin, doxycycline, minocycline, azithromycin and clarithromycin were determined in 23 M. genitalium strains. Three cultured strains had elevated MICs for moxifloxacin at 16, 4 and 2 mg/L and had SNPs with the amino-acid change Ser83→Ile in ParC (p<0.001) and 3 kinds of SNPs with amino-acid changes Asp99→Asn, Gly93→Cys and Met95→Ile in GyrA, respectively. Among a total of 148 M. genitalium positive urine specimens, the prevalence of A2058G and A2059G SNPs in the 23S rRNA gene and any SNPs in ParC increased from 4.8% and 22.6% in 2005–2009 to 42.2% and 53.1% in 2010–2017, respectively. If M. genitalium is considered multi-drug resistant in clinical specimens carrying SNPs in the 23S rRNA gene and Ser83→Ile in ParC, the prevalence of multi-drug resistance is 12.5% in 2010–2017 in Japan. In conclusion, the SNP resulting in Ser83→Ile in ParC is closely related to moxifloxacin resistance even though other factors may also affect treatment outcomes by moxifloxacin. The prevalence of circulating multi-drug resistant M. genitalium strains with macrolide- and fluoroquinolone-resistance is dramatically increasing in Japan.

What Is Resistance? Impact of Phenotypic versus Molecular Drug Resistance Testing on Therapy for Multi- and Extensively Drug-Resistant Tuberculosis

Rapid and accurate drug susceptibility testing (DST) is essential for the treatment of multi- and extensively drug-resistant tuberculosis (M/XDR-TB). We compared the utility of genotypic DST assays with phenotypic DST (pDST) using Bactec 960 MGIT or Löwenstein-Jensen to construct M/XDR-TB treatment regimens for a cohort of 25 consecutive M/XDR-TB patients and 15 possible anti-TB drugs. Genotypic DST results from Cepheid GeneXpert MTB/RIF (Xpert) and line probe assays (LPAs; Hain GenoType MTBDRplus 2.0 and MTBDRsl 2.0) and whole-genome sequencing (WGS) were translated into individual algorithm-derived treatment regimens for each patient. We further analyzed if discrepancies between the various methods were due to flaws in the genotypic or phenotypic test using MIC results. Compared with pDST, the average agreement in the number of drugs prescribed in genotypic regimens ranged from just 49% (95% confidence interval [CI], 39 to 59%) for Xpert and 63% (95% CI, 56 to 70%) for LPAs to 93% (95% CI, 88 to 98%) for WGS. Only the WGS regimens did not contain any drugs to which pDST showed resistance. Importantly, MIC testing revealed that pDST likely underestimated the true rate of resistance for key drugs (rifampin, levofloxacin, moxifloxacin, and kanamycin) because critical concentrations (CCs) were too high. WGS can be used to rule in resistance even in M/XDR strains with complex resistance patterns, but pDST for some drugs is still needed to confirm susceptibility and construct the final regimens. Some CCs for pDST need to be reexamined to avoid systematic false-susceptible results in low-level resistant isolates.

Moxifloxacin reduces Stenotrophomonas maltophilia adhesion to mouse intestinal tract in vitro

Stenotrophomonas maltophilia is an important opportunistic pathogen that affects immunocompromised individuals. Viable bacterial count method was used to count the number of adhered bacteria. The current study showed the efficiency of S. maltophilia (Sm2) adhesion on different parts of mouse intestinal tract (IT), small intestinal tract (SIT), large intestinal tract (LIT) and rectum (P<0.05) and this ability was equal for each part of IT [ANOVA test (P > 0.05)]. Moxifloxacin (0.03 x MIC) resulted a significant decrease in adhesion of S. maltophilia to SIT (P<0.05) versus control and other sub-inhibitory moxifloxacin concentrations (0.06 x and 1.2 x MIC). It can be concluded from the current study that the S. maltophilia (Sm2) has a good ability to adhere to mouse IT and the lowest concentrations of moxifloxacin (0.03 x MIC) reduced the ability of this bacterium to infect IT by reducing the ability of this bacterium to adhere to IT.