A Study of Resistome in Mexican Chili Powder as a Public Health Risk Factor

Chili powder is an important condiment around the world. However, according to various reports, the presence of pathogenic microorganisms could present a public health risk factor during its consumption. Therefore, microbiological quality assessment is required to understand key microbial functional traits, such as antibiotic resistance genes (ARGs). In this study, metagenomic next-generation sequencing (mNGS) and bioinformatics analysis were used to characterize the comprehensive profiles of the bacterial community and antibiotic resistance genes (ARGs) in 15 chili powder samples from different regions of Mexico. The initial bacterial load showed aerobic mesophilic bacteria (AMB) ranging between 6 × 103 and 7 × 108 CFU/g, sporulated mesophilic bacteria (SMB) from 4.3 × 103 to 2 × 109 CFU/g, and enterobacteria (En) from <100 to 2.3 × 106 CFU/g. The most representative families in the samples were Bacillaceae and Enterobacteriaceae, in which 18 potential pathogen-associated species were detected. In total, the resistome profile in the chili powder contained 68 unique genes, which conferred antibiotic resistance distributed in 13 different classes. Among the main classes of antibiotic resistance genes with a high abundance in almost all the samples were those related to multidrug, tetracycline, beta-lactam, aminoglycoside, and phenicol resistance. Our findings reveal the utility of mNGS in elucidating microbiological quality in chili powder to reduce the public health risks and the spread of potential pathogens with antibiotic resistance mechanisms.

[Efficacy and Mechanism of Tetracycline Adsorption by Boron-doped Mesoporous Carbon]

Using coconut shell and boric acid as raw materials， a new boron-doped coconut shell mesoporous carbon material （B-CSC） was prepared using a simple one-step pyrolysis method for efficient adsorption and removal of tetracycline pollutants in water. The effects of pyrolysis temperature and boron-carbon mass ratio on the adsorption performance under key preparation conditions were systematically studied， and their microstructure and physicochemical properties were characterized using a specific surface area and pore size analyzer （BET）， field emission scanning electron microscopy （SEM）， X-ray photon spectroscopy （XPS）， Raman spectrometer （Raman）， and Zeta potentiometer （Zeta）. The effects of initial pH， different metal cations， and different background water quality conditions on the adsorption effect were systematically investigated. Combined with material characterization and correlation analysis， the enhanced adsorption mechanism was discussed and analyzed in depth. The results showed that one-step pyrolysis could incorporate boron into the surface and crystal lattice of coconut shell charcoal， resulting in a larger specific surface area and pore volume， and the main forms of boron introduced were H3BO3， B2O3， B， and B4C. The adsorption capacity of B-CSC to tetracycline reached 297.65 mg·g-1， which was 8.9 times that of the original coconut shell mesoporous carbon （CSC）. At the same time， the adsorption capacity of B-CSC for rhodamine B （RhB）， bisphenol A（BPA）， and methylene blue （MB）， common pollutants in aquatic environments， was as high as 372.65， 255.24， and 147.82 mg·g-1， respectively. The adsorption process of B-CSC to tetracycline was dominated by physicochemical interaction， mainly involving liquid film diffusion， surface adsorption， mesoporous and microporous diffusion， and active site adsorption， and H3BO3 was the main adsorption site. The adsorption strengthening mechanism mainly reduced the chemical inertness of the carbon network and enhanced its π-π interaction and hydrogen bonding with tetracycline molecules.

Omadacycline pharmacokinetics/pharmacodynamics and efficacy against multidrug-resistant Mycobacterium tuberculosis in the hollow fiber system model

Seventy-five years ago, first-generation tetracyclines demonstrated limited efficacy in the treatment of tuberculosis but were more toxic than efficacious. We performed a series of pharmacokinetic/pharmacodynamic (PK/PD) experiments with a potentially safer third-generation tetracycline, omadacycline, for the treatment of multidrug-resistant tuberculosis (MDR-TB). Mycobacterium tuberculosis (Mtb) H37Rv and an MDR-TB clinical strain (16D) were used in the minimum inhibitory concentration (MIC) and static concentration-response studies in test tubes, followed by a PK/PD study using the hollow fiber system model of TB (HFS-TB) that examined six human-like omadacycline doses. The inhibitory sigmoid maximal effect (Emax) model and Monte Carlo experiments (MCEs) were used for data analysis and clinical dose-finding, respectively. The omadacycline MIC for both Mtb H37Rv and MDR-TB clinical strain was 16 mg/L but dropped to 4 mg/L with daily drug supplementation to account for omadacycline degradation. The Mycobacteria Growth Indicator Tube MIC was 2 mg/L. In the test tubes, omadacycline killed 4.39 log10 CFU/mL in 7 days. On Day 28 of the HFS-TB study, the Emax was 4.64 log10 CFU/mL, while exposure mediating 50% of Emax (EC50) was an area under the concentration-time curve to MIC (AUC0-24/MIC) ratio of 22.86. This translates to PK/PD optimal exposure or EC80 as AUC0-24/MIC of 26.93. The target attainment probability of the 300-mg daily oral dose was 90% but fell at MIC ≧4 mg/L. Omadacycline demonstrated efficacy and potency against both drug-susceptible and MDR-TB. Further studies are needed to identify the omadacycline effect in combination therapy for the treatment of both drug-susceptible and MDR-TB.

Characterization of the Binding Properties of Ten Aptamers Using the Intrinsic Fluorescence of Oxytetracycline

Tetracyclines are a class of commonly used four-ringed antibiotics. A series of DNA aptamers were recently obtained using the capture-SELEX (systematic evolution of ligands by exponential enrichment) method to bind to oxytetracycline, and one of the aptamers can bind to a few other tetracycline antibiotics as well. Upon binding to the aptamers, the intrinsic fluorescence of tetracycline antibiotics can be enhanced. At least 10 different DNA aptamers were isolated from the previous selection experiment. In this work, a systematic characterization of these ten aptamers was performed. Each of these aptamers shows a different degree of fluorescence enhancement ranging from around 1-fold to over 20-fold. Fluorescence enhancement was boosted in the presence of Mg2+ . Isothermal titration calorimetry (ITC) studies were done and showed a great variety in dissociation constant (Kd ) from 62 nM to 1.6 μM. Steady-state fluorescence spectroscopy and fluorescence lifetime studies showed a correlation between fluorescence lifetime and degree of fluorescence enhancement. A few aptamers showed slow binding kinetics, although no correlation was found between the kinetics of fluorescence change and degree of fluorescence enhancement. This is the first study of ten different aptamers for the same target, providing fundamental insights into aptamer binding and bioanalytical applications.

Tetracycline inhibits tick host reproduction by modulating bacterial microbiota, gene expression and metabolism levels

BACKGROUND

Ticks are disease vectors that are a matter of worldwide concern. Antibiotic treatments have been used to explore the interactions between ticks and their symbiotic microorganisms. In addition to altering the host microbial community, antibiotics can have toxic effects on the host.

RESULTS

In the tick Haemaphysalis longicornis, engorged females showed reproductive disruption after microinjection of tetracycline. Multi-omics approaches were implemented to unravel the mechanisms of tick reproductive inhibition in this study. There were no significant changes in bacterial density in the whole ticks on Day (D)2 or D4 after tetracycline treatment, whereas the bacterial microbial community was significantly altered, especially on D4. The relative abundances of the bacteria Staphylococcus, Bacillus and Pseudomonas decreased after tetracycline treatment, whereas the relative abundances of Coxiella and Rhodococcus increased. Ovarian transcriptional analysis revealed a cumulative effect of tetracycline treatment, as there was a significant increase in the number of differentially expressed genes with treatment time and a higher number of downregulated genes. The tick physiological pathways including lysosome, extracellular matrix (ECM)-receptor interaction, biosynthesis of ubiquinone and other terpenoids-quinones, insect hormone biosynthesis, and focal adhesion were significantly inhibited after 4 days of tetracycline treatment. Metabolite levels were altered after tetracycline treatment and the differences increased with treatment time. The differential metabolites were involved in a variety of physiological pathways; the downregulated metabolites were significantly enriched in the nicotinate and nicotinamide metabolism, galactose metabolism, and ether lipid metabolism pathways.

CONCLUSIONS

These findings indicate that tetracycline inhibits tick reproduction through the regulation of tick bacterial communities, gene expression and metabolic levels. The results may provide new strategies for tick control. © 2023 Society of Chemical Industry.

Role of proton pump inhibitors dosage and duration in Helicobacter pylori eradication treatment: Results from the European Registry on H. pylori management

BACKGROUND

Management of Helicobacter pylori (H. pylori) infection requires co-treatment with proton pump inhibitors (PPIs) and the use of antibiotics to achieve successful eradication.

AIM

To evaluate the role of dosage of PPIs and the duration of therapy in the effectiveness of H. pylori eradication treatments based on the 'European Registry on Helicobacter pylori management' (Hp-EuReg).

METHODS

Hp-EuReg is a multicentre, prospective, non-interventionist, international registry on the routine clinical practice of H. pylori management by European gastroenterologists. All infected adult patients were systematically registered from 2013 to 2022.

RESULTS

Overall, 36,579 patients from five countries with more than 1000 patients were analysed. Optimal (≥90%) first-line-modified intention-to-treat effectiveness was achieved with the following treatments: (1) 14-day therapies with clarithromycin-amoxicillin-bismuth and metronidazole-tetracycline-bismuth, both independently of the PPI dose prescribed; (2) All 10-day (except 10-day standard triple therapy) and 14-day therapies with high-dose PPIs; and (3) 10-day quadruple therapies with clarithromycin-amoxicillin-bismuth, metronidazole-tetracycline-bismuth, and clarithromycin-amoxicillin-metronidazole (sequential), all with standard-dose PPIs. In first-line treatment, optimal effectiveness was obtained with high-dose PPIs in all 14-day treatments, in 10- and 14-day bismuth quadruple therapies and in 10-day sequential with standard-dose PPIs. Optimal second-line effectiveness was achieved with (1) metronidazole-tetracycline-bismuth quadruple therapy for 14- and 10 days with standard and high-dose PPIs, respectively; and (2) levofloxacin-amoxicillin triple therapy for 14 days with high-dose PPIs. None of the 7-day therapies in both treatment lines achieved optimal effectiveness.

CONCLUSIONS

We recommend, in first-line treatment, the use of high-dose PPIs in 14-day triple therapy and in 10-or 14-day quadruple concomitant therapy in first-line treatment, while standard-dose PPIs would be sufficient in 10-day bismuth quadruple therapies. On the other hand, in second-line treatment, high-dose PPIs would be more beneficial in 14-day triple therapy with levofloxacin and amoxicillin or in 10-day bismuth quadruple therapy either as a three-in-one single capsule or in the traditional scheme.

Enhanced Biofilm Formation by Tetracycline in a Staphylococcus aureus Naturally Lacking ica Operon and atl

Staphylococcus aureus is a major, widespread pathogen, and its biofilm-forming characteristics make it even more difficult to eliminate by biocides. Tetracycline (TCY) is a major broad-spectrum antibiotic, the residues of which can cause deleterious health impacts, and subinhibitory concentrations of TCY have the potential to increase biofilm formation in S. aureus. In this study, we showed how the biofilm formation of S. aureus 123786 is enhanced in the presence of TCY at specific subinhibitory concentrations. S. aureus 123786 used in this study was identified as Staphylococcal Cassette Chromosome mec III, sequence type239 and naturally lacking ica operon and atl gene. Two assays were performed to quantify the formation of S. aureus biofilm. In the crystal violet (CV) assay, the absorbance values of biofilm stained with CV at optical density (OD)540 nm increased after 8 and 16 hr of incubation when the concentration of TCY was 1/2 minimum inhibitory concentration (MIC), whereas at the concentration of 1/16 MIC, the absorbance values increased after 16 and 24 hr of incubation. In tetrazolium salt reduction assay, the absorbance value at OD490 nm of S. aureus 123786 biofilms mixed with 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium solution increased after 8 hr when the concentration of TCY was 1/4 MIC, which may be correlated with the higher proliferation and maturation of biofilm. In conclusion, the biofilm formation of S. aureus 123786 could be enhanced in the presence of TCY at specific subinhibitory concentrations.

Effectiveness of Conventional Periodontal Treatment With Tetracycline Fiber Versus Minocycline Gel Application Subgingivally in Periodontitis Patients

BACKGROUND

Locally delivered antibiotics are adjunctive therapies for the selective removal or inhibition of pathogenic microbes in combination with scaling and root planing (SRP) for the management of periodontitis.

OBJECTIVE

The primary objective of this study was to evaluate the effectiveness of tetracycline fibers against minocycline gel when used as local drug delivery in conjunction with SRP for treating periodontitis.

METHODS AND MATERIALS

This is a pilot randomized open single, blinded trial study comparing three treatment modalities: SRP with topical tetracycline fibers (SRP+T), SRP with topical minocycline HCL 2% gel (SRP+M), and SRP only as a control group. Probing pocket depth (PPD), clinical attachment loss (CAL), and bleeding on probing (BOP) percentages were recorded at baseline, one month, and at the end of three months. The data were subjected to analysis using IBM Corp. Released 2019. IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY: IBM Corp. Repeated measures ANOVA was used to compare the clinical outcomes between the three treatment groups, accounting for the repeated measurements at baseline, one month, and three months. A p-value less than 0.05 at a 95% confidence interval was deemed statistically significant.

RESULTS

There were statistically significant changes within the groups in all the clinical parameters, including pocket depth, clinical attachment loss, and bleeding on probing score, at different time intervals, with the greatest mean pocket depth changes seen in the tetracycline group after one month (mean changes = 1.4 mm, P < 0.001) and over three months (mean changes = 1.79 mm, p < 0.001). For clinical attachment loss, after one month, the highest improvement in clinical level was seen in the minocycline group (mean changes = 0.7mm, p < 0.05), and the overall improvement was seen in the control group (mean changes = 1.1mm, p < 0.05). The minocycline group showed greater mean changes in bleeding on probing percentage, with the greatest changes after one month (mean changes = 19.34%, p < 0.001) and over three months (mean changes = 26.42%, p <0.001). However, there was no significant difference between the groups.

CONCLUSION

Locally delivered tetracycline and minocycline gel are effective as adjuncts to SRP and may improve the healing outcome in the management of periodontitis.

Inactivation of antibiotic-resistant bacteria Escherichia coli by electroporation

Introduction

In modern times, bacterial infections have become a growing problem in the medical community due to the emergence of antibiotic-resistant bacteria. In fact, the overuse and improper disposal of antibiotics have led to bacterial resistance and the presence of such bacteria in wastewater. Therefore, it is critical to develop effective strategies for dealing with antibiotic-resistant bacteria in wastewater. Electroporation has been found to be one of the most promising complementary techniques for bacterial inactivation because it is effective against a wide range of bacteria, is non-chemical and is highly optimizable. Many studies have demonstrated electroporation-assisted inactivation of bacteria, but rarely have clinical antibiotics or bacteria resistant to these antibiotics been used in the study. Therefore, the motivation for our study was to use a treatment regimen that combines antibiotics and electroporation to inactivate antibiotic-resistant bacteria.

Methods

We separately combined two antibiotics (tetracycline and chloramphenicol) to which the bacteria are resistant (with a different resistance mode) and electric pulses. We used three different concentrations of antibiotics (40, 80 and 150 µg/ml for tetracycline and 100, 500 and 2000 µg/ml for chloramphenicol, respectively) and four different electric field strengths (5, 10, 15 and 20 kV/cm) for electroporation.

Results and discussion

Our results show that electroporation effectively enhances the effect of antibiotics and inactivates antibiotic-resistant bacteria. The inactivation rate for tetracycline or chloramphenicol was found to be different and to increase with the strength of the pulsed electric field and/or the concentration of the antibiotic. In addition, we show that electroporation has a longer lasting effect (up to 24 hours), making bacteria vulnerable for a considerable time. The present work provides new insights into the use of electroporation to inactivate antibiotic-resistant bacteria in the aquatic environment.

Transmission of antimicrobial resistance in the gut microbiome of gregarious cockroaches: the importance of interaction between antibiotic exposed and non-exposed populations

Antimicrobial resistance (AMR) is a major global health concern, further complicated by its spread via the microbiome bacterial members. While mathematical models discuss AMR transmission through the symbiotic microbiome, experimental studies are scarce. Herein, we used a gregarious cockroach, Pycnoscelus surinamensis, as an in vivo animal model for AMR transmission investigations. We explored whether the effect of antimicrobial treatment is detectable with metagenomic sequencing, and whether AMR genes can be spread and established in unchallenged (not treated with antibiotics) individuals following contact with treated donors, and under various frequencies of interaction. Gut and soil substrate microbiomes were investigated by metagenomic sequencing for bacterial community composition and resistome profiling. We found that tetracycline treatment altered the treated gut microbiome by decreasing bacterial diversity and increasing the abundance of tetracycline resistance genes. Untreated cockroaches that interacted with treated donors also had elevated tetracycline resistance. The levels of resistance differed depending on the magnitude and frequency of donor transfer. Additionally, treated donors showed signs of microbiome recovery due to their interaction with the untreated ones. Similar patterns were also recorded in the soil substrate microbiomes. Our results shed light on how interacting microbiomes facilitate AMR gene transmission to previously unchallenged hosts, a dynamic influenced by the interaction frequencies, using an in vivo model to validate theoretical AMR transmission models.IMPORTANCEAntimicrobial resistance is a rising threat to human and animal health. The spread of resistance through the transmission of the symbiotic gut microbiome is of concern and has been explored in theoretical modeling studies. In this study, we employ gregarious insect populations to examine the emergence and transmission of antimicrobial resistance in vivo and validate modeling hypotheses. We find that antimicrobial treatment increases the levels of resistance in treated populations. Most importantly, we show that resistance increased in untreated populations after interacting with the treated ones. The level of resistance transmission was affected by the magnitude and frequency of population mixing. Our results highlight the importance of microbial transmission in the spread of antimicrobial resistance.

Promising photocatalytic activity of Ag2SO4-modified BiOCl/BFO heterostructures under visible light

In this work, a simple co-precipitation method for the preparation of Ag2SO4@BiOCl@Bi25FeO40 (BFO) was developed. Ultraviolet-visible spectrophotometric analysis, X-ray diffraction patterns, Fourier transform infrared spectroscopy (FT-IR), and scanning field emission electron microscopy (FESEM) were performed to characterize the newly synthesized nanocomposite. In addition, the EDX method was used to determine the actual material quantities. The synthesized samples of Bi25FeO40 and Ag2SO4 Bi25FeO40 showed high absorption in the visible region. Furthermore, the photocatalytic activity was significantly improved by the addition of Ag2SO4. The results showed photcatalytic efficiency was reached to about 99% with 0.01 g of Ag2SO4@BiOCl@Bi25FeO40 in pH 4 under visible light. The isoelectric pH of the photocatalayst was obtained 5. Also, kinetic study showed a first order mechanism for photodegradation. Moreover, a mechanistic study was proposed for the newly synthesized heterostructures.

Pharmacokinetic and pharmacodynamic evaluation of the atypical tetracyclines chelocardin and amidochelocardin in murine infection models

IMPORTANCE

There is a strong need to find novel treatment options against urinary tract infections associated with antimicrobial resistance. This study evaluates two atypical tetracyclines, namely chelocardin (CHD) and amidochelocardin (CDCHD), with respect to their pharmacokinetics and pharmacodynamics. We show CHD and CDCHD are cleared at high concentrations in mouse urine. Especially, CDCHD is highly effective in an ascending urinary tract infection model, suggesting further preclinical evaluation.

Hydroxyapatite: An antibiotic recruiting moiety for local treatment and prevention of bone infections

Treatment of chronic osteomyelitis by radical debridement and filling of the dead space with antibiotic containing calcium sulfate/hydroxyapatite (CaS/HA) bone substitute has shown excellent long-term outcomes. However, in extensive infections, sessile bacteria may remain in bone cells or soft tissues protected by biofilm leading to recurrences. The primary aim of this study was to evaluate if systemically administrated tetracycline (TET) could bind to pre-implanted HA particles and impart an antibacterial effect locally. In vitro studies indicated that the binding of TET to nano- and micro-sized HA particles was rapid and plateaued already at 1 h. Since protein passivation of HA after in-vivo implantation could affect HA-TET interaction, we investigated the effect of serum exposure on HA-TET binding in an antibacterial assay. Although, serum exposure reduced the zone of inhibition (ZOI) of Staphylococcus aureus, a significant ZOI could still be observed after pre-incubation of HA with serum. We could in addition show that zoledronic acid (ZA) competes for the same binding sites as TET and that exposure to high doses of ZA led to reduced TET-HA binding. In an in-vivo setting, we then confirmed that systemically administered TET seeks HA particles that were pre-implanted in muscle and subcutaneous pouches in rats and mice respectively, preventing HA particles from being colonized by S. aureus. Clinical Significance: This study describes a new drug delivery method that could prevent bacterial colonization of a HA biomaterial and reduce recurrences in bone infection.

Simultaneous removal of tetracycline and copper ions from wastewater by flow-electrode capacitive deionization

ABSTRACTTo effectively solve the problem of tetracycline (TC) and Cu2+ contamination in wastewater, this study innovatively proposed a low-energy flow-electrode capacitive deionization (FCDI) technology to simultaneously remove TC and Cu2+ from wastewater. The removal efficiencies of TC and Cu2+ using FCDI was investigated under various voltages, electrode flow rates, influent flow rates, and electrode liquid concentrations. The results showed that the removal efficiency of TC and Cu2+ was 60.78% and 84.43%, respectively. The energy consumption for TC and Cu2+ removal was only 1.76 and 1.10 kWh kg-1, which was lower than other electrochemical systems. The ion removal performance of the FCDI system remained stable after six cycles of continuous operation. These findings demonstrated the promising potential of FCDI as an innovative technology for the simultaneous removal of TC and Cu2+, presenting a significant prospects for application in the water treatment field.

Engineering U1-Based Tetracycline-Inducible Riboswitches to Control Gene Expression in Mammals

Synthetic riboswitches are promising regulatory devices due to their small size, lack of immunogenicity, and ability to fine-tune gene expression in the absence of exogenous trans-acting factors. Based on a gene inhibitory system developed at our lab, termed U1snRNP interference (U1i), we developed tetracycline (TC)-inducible riboswitches that modulate mRNA polyadenylation through selective U1 snRNP recruitment. First, we engineered different TC-U1i riboswitches, which repress gene expression unless TC is added, leading to inductions of gene expression of 3-to-4-fold. Second, we developed a technique called Systematic Evolution of Riboswitches by Exponential Enrichment (SEREX), to isolate riboswitches with enhanced U1 snRNP binding capacity and activity, achieving inducibilities of up to 8-fold. Interestingly, by multiplexing riboswitches we increased inductions up to 37-fold. Finally, we demonstrated that U1i-based riboswitches are dose-dependent and reversible and can regulate the expression of reporter and endogenous genes in culture cells and mouse models, resulting in attractive systems for gene therapy applications. Our work probes SEREX as a much-needed technology for the in vitro identification of riboswitches capable of regulating gene expression in vivo.

Review of Teratogenic Effects of Leflunomide, Accutane, Thalidomide, Warfarin, Tetracycline, and Angiotensin-Converting Enzyme Inhibitors

Teratogenic agents have been shown to have drastic and detrimental effects on fetuses if exposed to the agent during uterine life. The most sensitive time for a developing fetus is during the first trimester, and teratogenic exposure during this time can lead to severe deformities in the fetus. The Food and Drug Administration has categorized teratogenic agents based on the severity of their effect on the fetus; these categories include A, B, C, D, and X. Category A is the safest, with the most dangerous, and highly contraindicated in pregnant patients being Category X. This review article will discuss the teratogenic agents leflunomide, isotretinoin, thalidomide, warfarin, tetracycline, and angiotensinogen-converting enzyme inhibitors. Leflunomide can cause cranioschisis, exencephaly, and vertebral, head, and limb malformations. Isotretinoin's main teratogenic effects include central nervous system malformations, hydrocephalus, eye abnormalities, cardiac septal defects, thymus abnormalities, spontaneous abortions, and external ear abnormalities. Thalidomide has been shown to cause limb deformities, bowel atresia, and heart defects when the embryo is exposed to the agent during development. Warfarin can lead to spontaneous abortion and intrauterine death, as well as nasal hypoplasia, hypoplasia of extremities, cardiac defects, scoliosis, and mental retardation when exposed in utero. Tetracycline's teratogenic effects include gastrointestinal distress, esophageal ulceration and strictures, teeth discoloration, hepatotoxicity, and calcifications. Angiotensinogen-converting enzyme inhibitors can cause skull hyperplasia, anuria, hypotension, renal failure, lung hypoplasia, skeletal deformation, oligohydramnios, and fetal death. Teratogenic effects can be avoided if the pregnant patient is educated on the teratogenic effects of these agents.

Doxycycline-Induced Intracranial Hypertension Presenting as Unilateral Pulsatile Tinnitus

Background

Pulsatile tinnitus (PT) is increasingly recognized as a cardinal symptom of idiopathic intracranial hypertension (IIH). However, clinicians should remain aware of other causes of nonidiopathic or secondary intracranial hypertension manifesting as PT. We present 2 patients with isolated PT (without accompanying headache, blurred vision, and papilledema) thought to be secondary to tetracycline-induced intracranial hypertension. To our knowledge, these are the first cases of PT as the presenting symptom of this condition.

Cases

A 41-year-old female (body mass index [BMI] 29 kg/m2) with ocular rosacea was initially treated with minocycline. Shortly after transitioning to oral doxycycline and erythromycin eye ointment, she noted left-sided PT. Her PT resolved after discontinuing doxycycline. In a second case, a 39-year-old female (BMI 19 kg/m2) with acne presented with a three-year history of left-sided PT while on long-term oral doxycycline for many years. She denied visual or auditory changes and atypical headaches. MRI findings were concerning for intracranial hypertension. Three months later, the patient was seen by neuro-ophthalmology, with findings suggesting prior papilledema. The patient reported PT improvement after discontinuing doxycycline.

Conclusions

This case series highlights 2 cases of isolated PT as the sole symptom of intracranial hypertension that resolved with tetracycline cessation. The presentation and unexpected improvement following tetracycline discontinuation are atypical compared with previous reports of tetracycline-induced intracranial hypertension. Clinicians should maintain a high index of suspicion for all types of intracranial hypertension (idiopathic and secondary), even in patients with a lower BMI. Current and prior medications should be reviewed when considering the etiology of intracranial hypertension.

Determination of Tetracycline Antibiotics in Milk by Solid-Phase Extraction Using a Coordination Polymer Based on Cobalt Trimesinate as a Sorbent

The coordination polymer was obtained based on cobalt trimesinate. It was characterized by elemental analysis, IR spectroscopy, X-ray diffraction analysis and scanning electron microscopy. The polymer was studied as a sorbent for solid-phase extraction of tetracycline antibiotics. Cobalt trimesinate had a high adsorption capacity (400 mg/g). Antibiotic adsorption followed the pseudo-second-order kinetic model and the Freundlich isotherm model. The process proceeded spontaneously, as indicated by the calculated thermodynamic parameters. The resulting coordination polymer has good stability and recyclability. The possibility of using cobalt trimesinate for the determination of tetracycline in various milk samples was investigated. This work holds great promise for the development and application of a cobalt trimesinate-based coordination polymer for use in sample preparation to replace the time-consuming vacuum evaporation procedure with a relatively simple solid-phase extraction procedure.

Highly Stable Fluorescent-Traffic-Light Sensor for Point-of-Care Detection of Tetracycline

Fluorescent point-of-care (POC) sensors have found great utility in fields like clinical diagnosis, food testing, and environmental monitoring. Herein, we developed a highly stable POC sensor that enabled the visual detection of tetracycline (TC) in a distinct fluorescent-traffic-light manner. In the sensor, a composite material of copper nanoclusters and metal-organic framework (CuNCs@MOF-5) prepared with a facile one-pot synthetic strategy was employed as the core element for target recognition and signal transduction. As evidenced by experiments, the as-prepared CuNCs@MOF-5 exhibited significantly improved fluorescence properties in terms of emission enhancement (about 28-fold) and stability improvement (over 110 days) compared to the CuNCs without confining and protection by MOF-5. More importantly, it was found that TC could uniquely interact with Zn(II) to trigger the disassembly of CuNCs@MOF-5, resulting in green fluorescence emission from the TC-Zn(II) complex and red fluorescence weakening of CuNCs. On the basis of this finding, a simple and stable sensor was proposed for POC detection of TC, which demonstrated high sensitivity, selectivity, and reproducibility. In addition to homogeneous visual detection in a 96-well plate, a CuNCs@MOF-5-contained agarose gel array was easily fabricated to achieve direct detection of TC in milk without any pretreatment, thanks to the size-sieving effect of the gel. Moreover, a test paper array was also put forward for low-cost TC detection, which indicates the extensibility and practicability of this sensing strategy.

Nanopore Sequencing Assessment of Bacterial Pathogens and Associated Antibiotic Resistance Genes in Environmental Samples

As seen in earlier and present pandemics, monitoring pathogens in the environment can offer multiple insights on their spread, evolution, and even future outbreaks. The present paper assesses the opportunity to detect microbial pathogens and associated antibiotic resistance genes, in relation to specific pathogen sources, by using nanopore sequencing in municipal waters and wastewaters in Romania. The main results indicated that waters collecting effluents from a meat processing facility exhibit altered communities' diversity and abundance, with reduced values (101-108 and 0.86-0.91) of Chao1 and, respectively, Simpson diversity indices and Campylobacterales as main order, compared with other types of municipal waters where the same diversity index had much higher values of 172-214 and 0.97-0.98, and Burkholderiaceae and Pseudomonadaceae were the most abundant families. Moreover, the incidence and type of antibiotic resistance genes were significantly influenced by the proximity of antibiotic sources, with either tetracycline (up to 45% of total reads) or neomycin, streptomycin and tobramycin (up to 3.8% total reads) resistance incidence being shaped by the sampling site. As such, nanopore sequencing proves to be an easy-to-use, accessible molecular technique for environmental pathogen surveillance and associated antibiotic resistance genes.

Removal of tetracycline by natural and iron-modified orange peel from aqueous solutions: processes in batch, column, and mechanism

Natural (OP) and iron modified orange peel (Fe-OP) were used for the removal of tetracycline from aqueous solutions in batch and fixed bed column systems. The adsorbents were characterized by infrared spectroscopy (IR) and the morphologies of the surfaces before and after tetracycline removal were determined by scanning electron microscope and the elemental analysis was performed by X-ray dispersive spectroscopy (EDS). The kinetic behaviour showed that the equilibrium was reached in 24 and 10 h for OP and Fe-OP respectively, the data were adjusted to both the pseudo second order and intraparticle diffusion models which indicate a chemisorption mechanism and the adsorption process is controlled by the intraparticle diffusion process. The isotherms showed that the adsorption capacity was eight times higher for Fe-OP than OP and the data were best fitted to the Freundlich model indicating that the materials are heterogeneous. The effect of flow rate, influent concentration and adsorbent mass were determined in the column system. The data were adjusted to the Thomas, Adams-Bohart and Yoon-Nelson models, and the best adjustment of data was with the first one. The adsorption capacities in the column system were about half of those obtained in the batch system. These adsorbents show good properties for the removal of tetracycline from water.

Determination of Antimicrobial Resistance and the Impact of Imipenem + Cilastatin Synergy with Tetracycline in Pseudomonas aeruginosa Isolates from Sepsis

Pseudomonas aeruginosa is among the most ubiquitous bacteria in the natural world, exhibiting metabolic and physiological versatility, which makes it highly adaptable. Imipenem + cilastatin and tetracycline are antibiotic combinations commonly used to treat infections caused by P. aeruginosa, including serious infections such as sepsis. In the context of bacterial infections, biofilm, formed by bacterial cells surrounded by extracellular substances forming a matrix, plays a pivotal role in the resistance of P. aeruginosa to antibiotics. This study aimed to characterize a representative panel of P. aeruginosa isolates from septicemias, assessing their susceptibility to various antibiotics, specifically, imipenem + cilastatin and tetracycline, and the impact of these treatments on biofilm formation. Results from antibiotic susceptibility tests revealed sensitivity in most isolates to six antibiotics, with four showing near or equal to 100% sensitivity. However, resistance was observed in some antibiotics, albeit at minimal levels. Notably, tetracycline showed a 100% resistance phenotype, while imipenem + cilastatin predominantly displayed an intermediate phenotype (85.72%), with some resistance (38.1%). Microdilution susceptibility testing identified effective combinations against different isolates. Regarding biofilm formation, P. aeruginosa demonstrated the ability to produce biofilms. The staining of microtiter plates confirmed that specific concentrations of imipenem + cilastatin and tetracycline could inhibit biofilm production. A significant proportion of isolates exhibited resistance to aminoglycoside antibiotics because of the presence of modifying genes (aac(3)-II and aac(3)-III), reducing their effectiveness. This study also explored various resistance genes, unveiling diverse resistance mechanisms among P. aeruginosa isolates. Several virulence genes were detected, including the las quorum-sensing system genes (lasI and lasR) in a significant proportion of isolates, contributing to virulence factor activation. However, genes related to the type IV pili (T4P) system (pilB and pilA) were found in limited isolates. In conclusion, this comprehensive study sheds light on the intricate dynamics of P. aeruginosa, a remarkably adaptable bacterium with a widespread presence in the natural world. Our findings provide valuable insights into the ongoing battle against P. aeruginosa infections, highlighting the need for tailored antibiotic therapies and innovative approaches to combat biofilm-related resistance.

Tetracycline residues in fresh dairy milk from three districts in Indonesia: Occurrence and dietary exposure assessment

Background and Aim

Milk can introduce antibiotics into the human diet which poses a public health risk. Therefore, a study to determine the tetracycline residue in dairy milk and its health risk assessment is needed. A cross-sectional study was performed to detect tetracycline residues in fresh dairy milk samples collected from the districts of Malang, Boyolali, and Padang Panjang, Indonesia, and to evaluate dietary exposure to tetracycline residues through milk consumption in 10-12-year-old children and adults.

Materials and Methods

A total of 203 fresh dairy milk samples were collected from local and smallholder dairy cows in Malang, Boyolali, and Padang Panjang in April and August 2018. High-performance liquid chromatography equipped with a photodiode array at 355 and 368 nm was used to detect tetracycline residues. Data were evaluated for dietary exposure assessment.

Results

The results showed that the most common residue found was chlortetracycline (8.37%), followed by tetracycline (7.88%) and oxytetracycline (5.91%) in the concentration range of 14.8-498.4, 11.7-49.4, and 11.6-85.6 ng/g, respectively. Seven (3.45%) samples exceeded the maximum residue limit (MRL) for chlortetracycline. However, neither oxytetracycline nor tetracycline residues exceeded the MRL. The mean concentration of the tetracycline residues was 21.76-137.05 ng/g, resulting in an estimated daily intake of 16.46-172.83 ng/kg body weight/day.

Conclusion

Tetracycline residues were found in almost all milk sampling locations. The highest prevalence and residue concentration were obtained from chlortetracycline. Estimated daily intake of tetracycline through milk by 10-12-year-old children and adult consumers was low and the risk to consumers was negligible.

The antimicrobial peptide Esc(1-21)-1c increases susceptibility of Pseudomonas aeruginosa to conventional antibiotics by decreasing the expression of the MexAB-OprM efflux pump

Introduction: The increase in bacterial strains resistant to conventional antibiotics is an alarming problem for human health and could lead to pandemics in the future. Among bacterial pathogens responsible for a large variety of severe infections there is Pseudomonas aeruginosa. Therefore, there is an urgent need for new molecules with antimicrobial activity or that can act as adjuvants of antibiotics already in use. In this scenario, antimicrobial peptides (AMPs) hold great promise. Recently, we characterized a frog-skin AMP derived from esculentin-1a, namely Esc(1-21)-1c, endowed with antipseudomonal activity without being cytotoxic to human cells. Methods: The combinatorial effect of the peptide and antibiotics was investigated through the checkerboard assay, differential proteomic and transcriptional analysis. Results: Here, we found that Esc(1-21)-1c can synergistically inhibit the growth of P. aeruginosa cells with three different antibiotics, including tetracycline. We therefore investigated the underlying mechanism implemented by the peptide using a differential proteomic approach. The data revealed a significant decrease in the production of three proteins belonging to the MexAB-OprM efflux pump upon treatment with sub-inhibitory concentration of Esc(1-21)-1c. Down-regulation of these proteins was confirmed by transcriptional analysis and direct measurement of their relative levels in bacterial cells by tandem mass spectrometry analysis in multiple reaction monitoring scan mode. Conclusion: These evidences suggest that treatment with Esc(1-21)-1c in combination with antibiotics would increase the intracellular drug content making bacteria more susceptible to the antibiotic. Overall, these results highlight the importance of characterizing new molecules able to synergize with conventional antibiotics, paving the way for the development of alternative therapeutic strategies based on AMP/antibiotic formulations to counteract the emergence of resistant bacterial strains and increase the use of "old" antibiotics in medical practice.

Investigation of enhanced degradation of the antibiotic under visible in novel B/ZnO/TiO2nanocomposite and its electrical energy consumption

Both ZnO and TiO2are common semiconducting metal oxides with high mechanical and chemical durability. However, they only have good photocatalytic ability in the UV region, besides the rapid recombination between electrons and holes reduces the efficiency of the decomposition of organic substances. To improve their catalytic efficiency, in this study, ZnO and TiO2were doped with B to produce the novel B/ZnO/TiO2nanocomposites for degrading tetracycline hydrochloride (TCH) in the aqueous solution. The characteristics of samples were analyzed by the diffuse reflectance ultraviolet-visible (DR/UV-vis), scanning electron microscope (SEM), energy-dispersive (EDS), Fourier transform infrared spectroscopy (FT-IR), and x-ray diffraction (XRD) techniques. The 3B/ZnO/TiO2sample had a band gap energy (Eg) of 3.21 eV. Although the B/ZnO/TiO2sample had a tightly aggregated morphology composed of many nanoparticles in 33-137 nm, it still exhibited a higher uniformly and photocatalytic efficiency than ZnO and ZnO/TiO2. At the optimal doped B of 3 wt%, the degradation efficiency (DE) was achieved at 96.33% with a rate constant of 0.067 min-1. The factors that affect the photocatalytic process such as the initial TCH concentration, the catalyst content, and the pH solution were comprehensively investigated. In addition, the stability of 3B/ZnO/TiO2nanocomposite was evaluated via three consecutive cycles and the DE was 69.75% in 3rd cycle. The Z-scheme mechanism was proposed for the photocatalytic mechanism of TCH in the B/ZnO/TiO2catalyst. In addition, electrical energy consumption was estimated that the electrical energy per order only was 29.05 kW.h.l-1.