Development of co-doped ZnS-CdS quantum dots based composite sensor for the detection of cefixime (CXM) and tetracycline (TET), and application in real samples from local dairies

The excessive use of antibiotics, particularly Cefixime (CXM) and tetracycline (TET), poses serious risks to human health and the environment. This study presents a novel detection method utilizing zinc sulfide-cadmium sulfide/cobalt (ZnS-CdS/Co) quantum dots, characterized through scanning electron microscopy (SEM), photoluminescence (PL), energy dispersive X-ray (EDX), mapping, Line scan, Fourier-transform infrared spectroscopy (FT-IR) techniques, and X-ray diffraction (XRD). Aqueous solutions of varied TET and CXM concentrations were prepared and analyzed using these synthesized quantum dots. The analysis revealed a significant decrease in fluorescence intensity with increasing antibiotic concentrations, demonstrating the method's high specificity and sensitivity. Recovery experiments with spiked milk samples yielded high accuracy, with CXM recovery rates ranging from 96.0 to 100.77% for Bistoon milk and 100.5-100.33% for Kalleh milk; TET recovery rates ranged from 97.2 to 106.0% for Bistoon milk and 93.16-102.5% for Kalleh milk. The optimized ZnS-CdS/Co nanoparticles showed low detection limits of 4.5 nM for CXM and 5.2 nM for TET. These findings underscore the potential of this rapid detection system as an effective tool for monitoring antibiotic residues in food products, significantly contributing to food safety and environmental sustainability. Future research could focus on enhancing the selectivity of these quantum dots for broader applications in complex matrices, promoting more sustainable antibiotic monitoring practices.

The binding modes of brazilin and hematein from Caesalpinia sappan L. to Cutibacterium acnes lipase: Simulation studies

The growing concern over antimicrobial resistance in Cutibacterium acnes (C. acnes) has spurred interest in alternative acne treatments, particularly herbal medicines. This study evaluates the binding affinities of established anti-acne agents-ketoconazole (KET) and tetracycline (TET)-alongside natural compounds, brazilin (BRA) and hematein (HEM), derived from Caesalpinia sappan L. (C. sappan), to C. acnes lipase. Through molecular docking and dynamics simulations, we demonstrate that the asymmetric lipase dimer operates independently. Bulky compounds such as KET and TET inhibit lipase activity via π-π interactions, primarily targeting the lid domain. In contrast, smaller ligands BRA and HEM exhibit unique binding modes: BRA mirrors TET by localizing near the lid domain, while HEM shows dual interactions with both the lid and catalytic sites. These results underscore the potential of BRA and HEM as promising anti-acne agents, indicating that C. sappan could be an effective herbal remedy for acne. This study provides a foundation for further exploration of natural products in combating acne and mitigating antimicrobial resistance.

Prevalence of antibiotic-resistant Cutibacterium acnes (formerly Propionibacterium acnes) isolates, a systematic review and meta-analysis

OBJECTIVE

This study aimed to assess the overall antibiotic susceptibility of Cutibacterium acnes (C. acnes), a bacterium implicated in acne vulgaris, with a particular focus on clindamycin and fluoroquinolones, which are commonly used in inflammatory acne treatment.

METHODS

A systematic search of Scopus, PubMed, Web of Science and EMBASE databases was conducted to identify relevant studies. Pooled prevalence estimates were calculated using a random-effects model, and additional analyses included quality assessment, evaluation of publication bias, meta-regression and subgroup analyses based on antimicrobial susceptibility methods and year of publication.

RESULTS

The analysis incorporated a total of 39 studies. The random-effects model revealed that the proportion of clindamycin-resistant isolates was 0.031 (95% CI: 0.014-0.071). Additionally, macrolides, including erythromycin (0.366; 95% CI: 0.302-0.434) and azithromycin (0.149; 95% CI: 0.061-0.322), exhibited distinct prevalence rates. Tetracyclines, including doxycycline (0.079; 95% CI: 0.014-0.071), tetracycline (0.062; 95% CI: 0.036-0.107) and minocycline (0.025; 95% CI: 0.012-0.051), displayed varying prevalence estimates. Fluoroquinolones, including ciprofloxacin (0.050; 95% CI: 0.017-0.140) and levofloxacin (0.061; 95% CI: 0.015-0.217), demonstrated unique prevalence rates. Additionally, the prevalence of the combination antibiotic trimethoprim/sulfamethoxazole (SXT) was estimated to be 0.087 (95% CI: 0.033-0.208).

CONCLUSION

The study findings highlight a concerning increase in antimicrobial-resistant C. acnes with the use of antibiotics in acne treatment. The strategic utilization of appropriate antimicrobials has emerged as a crucial measure to mitigate the emergence of antimicrobial-resistant skin bacteria in acne management.

Clinical Care of Acne Vulgaris for Transgender and Gender Diverse Youth

Primary care providers have reported feeling ill-equipped to care for transgender and gender diverse (TGD) patients because of lack of training, and their treatment of acne has been shown to be variable and not standardized. This is an important practice gap, as TGD youth represent a historically underserved population in medicine, despite data suggesting that up to 9.2% of high school-age adolescents identify as TGD. Although needs and expectations for quality health-care in TGD youth do not necessarily differ from their cisgender peers, TGD adolescents have unique considerations in their care and are at risk for negative social and emotional outcomes secondary to minority stress, discrimination, and rejection by peers and family. Acne is estimated to affect approximately 85% of adolescents and is associated with negative mental health outcomes, including suicidal ideation, low self-esteem, and depression. As such, knowledgeable and culturally informed care of acne in TGD adolescents has important implications for quality of life for patients who desire effective treatment. This review article addresses these practice gaps by summarizing an approach to acne evaluation and management with an emphasis on appropriate regimens for TGD youth, and the unique psychosocial and medical considerations for this population.

Tetracyclines Revisited: Tetracyclines in the Field of Dermatology

BACKGROUND

Tetracyclines are a class of broad-spectrum antibiotics favored by dermatologists. Over the last decade, the clinical efficacy of tetracyclines has expanded into various dermatoses.

SUMMARY

This review tries to encompass the possible indications of tetracycline in the field of dermatology and possible mechanisms of action. This comprehensive review encompasses all possible indications of tetracyclines besides acne vulgaris and rosacea: hidradenitis suppurativa, autoimmune bullous dermatoses, vitiligo, alopecia, prurigo pigmentosa, granulomatous dermatoses, Kaposi's sarcoma, cold urticaria, atopic dermatitis, scrub typhus, scarring, and miscellaneous dermatoses. We also focus on the recently approved sarecycline, a third-generation narrow-spectrum tetracycline, and its clinical efficacy and potential impact on the microbiome. Our review provides a better understanding of this extremely familiar drug class and encourages its use in a wider spectrum of dermatologic diseases and symptoms.

KEY MESSAGES

This study comprehensively reviewed the current literature on potential indications of tetracyclines in the field of dermatology.

Effect of oral doxycycline, azithromycin and isotretinoin on haematological inflammatory markers and interleukin-17A levels in acne vulgaris: a single blinded randomised interventional study

Amidst the existing literature on the effect of isotretinoin on serum interleukin-17 levels in acne patients, the effects of oral antibiotics azithromycin and doxycycline on serum interleukin-17 is scarce. We conducted an investigator blinded randomized interventional study to compare the effect of doxycycline, azithromycin and isotretinoin on inflammatory markers and Interleukin-17A (IL-17A) levels in acne. Patients were randomized and received the treatment according to treatment arm till 12 weeks. At baseline and 12 weeks/treatment completion, clinical improvement and Red-cell-distribution width (RDW),Neutrophil-lymphocyte ratio(NLR),Platelet-lymphocyte ratio(PLR), Mean-Platelet volume(MPV), Platelet-distribution width(PDW) and Interleukin-17A levels were analysed. P-value < 0.05 was considered statistically significant. Out of 120 patients, 110 patients completed the study. Baseline Global acne grading scale (GAGS) in doxycycline, azithromycin or isotretinoin group was 24.32  ± 3.119, 24.12 ± 2.804 and 25.10 ± 3.985 respectively and post-treatment was 5.216  ± 1.88, 7.265 ± 2.17 and 2.769 ± 1.08. All the drugs caused a statistically significant decrease in RDW and IL-17 A levels. Baseline levels of IL-17 A were significantly higher in patients with higher GAGS and post-acne scarring. One of the limitations of our study was that we excluded severe nodulocystic acne patients thereby these results have to be carefully extrapolated.

Enhanced adsorption-photodegradation of tetracycline using Ce-N-co-doped AC/TiO2 photocatalyst: isotherms, kinetics, mechanism, and thermodynamic insight

Excessive use of tetracycline (TC) is alarming owing to its increased detection in water systems. In this study, a photocatalyst was developed to degrade TC using a Ce-N-co-doped AC/TiO2 photocatalyst, denoted as Ce/N-AC/TiO2, prepared using the sol-gel method assisted by microwave radiation, speeding up the synthesis process. Ce/N-AC/TiO2 achieved maximum TC degradation of 93.1% under UV light with optimum sorption system conditions of an initial concentration of 10 mg L-1, pH 7, and 30 ℃, under 120 min. Scavenger experiments revealed that holes and superoxide radicals were the active species influencing the photodegradation process. The TC degradation was appropriately fitted with Langmuir isotherms and a pseudo-second-order (PSO) kinetic model. The change in enthalpy (ΔH) (2.43 kJ mol-1), entropy (ΔS) (0.024 kJ mol-1), and Gibbs free energy (ΔG) (- 4.941 to - 5.802 kJ mol-1) suggested that the adsorption process was spontaneous, favourable, and endothermic. Electrostatic interaction, hydrogen bonding, pore-filling, cationic-π, n-π, and π-π interaction were among the interactions involved between TC and Ce/N-AC/TiO2. Furthermore, Ce/N-AC/TiO2 stability was confirmed through 80% removal efficiency even after the fifth reuse cycle. Notably, this work provides new insight into the production of efficient, reusable, and enhanced photocatalysts using a rapid and cost-effective microwave-assisted synthesis process for pollutant remediation.

Transdermal Delivery System of Doxycycline-Loaded Niosomal Gels: Toward Enhancing Doxycycline Stability

Doxycycline (DOX) is an antimicrobial agent that is susceptible to photosensitivity and thermal degradation. It addition, it causes gastrointestinal side effects when taken orally. Therefore, the development of alternative formulations is necessary to improve drug stability and promote patient compliance. The aim of the present study was to encapsulate DOX in niosomes as a nanocarrier to deliver DOX transdermally and enhance its stability in the formulation. DOX niosomes were prepared using nonionic surfactants, cholesterol, and dihexadecyl phosphate (DCP). After that, niosomes were characterized in terms of practical size (PS), zeta potential (ZP), morphology, and entrapment efficacy (EE%). DOX niosomal gels were then prepared using Carbopol and penetration enhancers (poly(ethylene glycol) 400 (PEG 400) and propylene glycol (PG)). The flux of DOX from the optimized formula was 322.86 μg/cm2/h over 5 h, which equates to 71.2% of DOX. Furthermore, neither the DOX niosomal gel (D3) nor the comparable blank niosomal gel had a negative influence on human dermal fibroblast (HDF) cells. The findings of the antimicrobial effectiveness of DOX niosomes indicated that the niosomal formulation improved the antibacterial activity of DOX against E. coli. Permeation studies demonstrated significantly higher DOX permeation when the niosomal gel was applied to rat skin, compared to the conventional gel. Permeability parameters such as flux and the permeability coefficient increased more than 10-fold using the niosomal gels compared with those of conventional gels. In conclusion, a new niosomal gel formulation could serve as an effective alternative for the commercially available form of DOX.

The combination therapy using tyrosine kinase receptors inhibitors and repurposed drugs to target patient-derived glioblastoma stem cells

The lesson from many studies investigating the efficacy of targeted therapy in glioblastoma (GBM) showed that a future perspective should be focused on combining multiple target treatments. Our research aimed to assess the efficacy of drug combinations against glioblastoma stem cells (GSCs). Patient-derived cells U3042, U3009, and U3039 were obtained from the Human Glioblastoma Cell Culture resource. Additionally, the study was conducted on a GBM commercial U251 cell line. Gene expression analysis related to receptor tyrosine kinases (RTKs), stem cell markers and genes associated with significant molecular targets was performed, and selected proteins encoded by these genes were assessed using the immunofluorescence and flow cytometry methods. The cytotoxicity studies were preceded by analyzing the expression of specific proteins that serve as targets for selected drugs. The cytotoxicity study using the MTS assay was conducted to evaluate the effects of selected drugs/candidates in monotherapy and combinations. The most cytotoxic compounds for U3042 cells were Disulfiram combined with Copper gluconate (DSF/Cu), Dacomitinib, and Foretinib with IC50 values of 52.37 nM, 4.38 µM, and 4.54 µM after 24 h incubation, respectively. Interactions were assessed using SynergyFinder Plus software. The analysis enabled the identification of the most effective drug combinations against patient-derived GSCs. Our findings indicate that the most promising drug combinations are Dacomitinib and Foretinib, Dacomitinib and DSF/Cu, and Foretinib and AZD3759. Since most tested combinations have not been previously examined against glioblastoma stem-like cells, these results can shed new light on designing the therapeutic approach to target the GSC population.

Antimicrobial and anti-inflammatory effects of BenTooth: A natural product blend of burdock root, persimmon leaf extracts, and quercetin on periodontal disease

Periodontal disease represents a condition that exhibits substantial global morbidity, and is characterized by the infection and inflammation of the periodontal tissue effectuated by bacterial pathogens. The present study aimed at evaluating the therapeutic efficacy of BenTooth, an edible natural product mixture comprising burdock root extract, persimmon leaf extract and quercetin, against periodontitis both in vitro and in vivo. BenTooth was examined for antimicrobial properties and its impact on cellular responses related to inflammation and bone resorption. Its effects were also assessed in a rat model of ligature-induced periodontitis. BenTooth demonstrated potent antimicrobial activity against P. gingivalis and S. mutans. In RAW264.7 cells, it notably diminished the expression of inducible nitric oxide synthase and cyclooxygenase-2, as well as reduced interleukin-6 and tumor necrosis factor-α levels triggered by P. gingivalis-derived lipopolysaccharide. Furthermore, BenTooth inhibited osteoclastogenesis mediated by the receptor activator of nuclear factor κB ligand. In the rat model, BenTooth consumption mitigated the ligature-induced expansion in distance between the cementoenamel junction and the alveolar bone crest and bolstered the bone volume fraction. These results present BenTooth as a potential therapeutic candidate for the prevention and remediation of periodontal diseases.

Triple Combination Clindamycin Phosphate 1.2%/Adapalene 0.15%/Benzoyl Peroxide 3.1% for Acne: Efficacy and Safety from a Pooled Phase 3 Analysis

INTRODUCTION

A three-pronged approach to acne treatment combining an antibiotic, antimicrobial, and retinoid may be more efficacious than single/double treatments while potentially reducing antibiotic resistance. This study evaluated the efficacy and safety of the first fixed-dose, triple-combination topical acne product, clindamycin 1.2%/adapalene 0.15%/benzoyl peroxide (BPO) 3.1% gel (CAB) using pooled phase 3 data.

METHODS

In two identical phase 3 (N = 183; N = 180), double-blind, 12-week studies, participants aged ≥ 9 years with moderate-to-severe acne were randomized 2:1 to receive once-daily CAB or vehicle gel. Endpoints included ≥ 2-grade reduction from baseline in Evaluator's Global Severity Score and clear/almost clear skin (treatment success) and least-squares mean percent change from baseline in acne lesion counts. Treatment-emergent adverse events (TEAEs) and cutaneous safety/tolerability were evaluated.

RESULTS

At week 12, 50.0% of participants achieved treatment success with CAB versus 22.6% with vehicle gel (P < 0.001). CAB resulted in > 70% reductions in inflammatory and noninflammatory lesions at week 12 (77.9% and 73.0%, respectively), which were significantly greater than vehicle (57.9% and 48.2%; P < 0.001, both). Most TEAEs were of mild-moderate severity, and < 3% of CAB-treated participants discontinued study/treatment because of AEs. Transient increases from baseline in scaling, erythema, itching, burning, and stinging were observed with CAB, but resolved back to or near baseline values by week 12.

CONCLUSIONS

The innovative fixed-dose, triple-combination clindamycin phosphate 1.2%/adapalene 0.15%/BPO 3.1% gel was efficacious and well tolerated in children, adolescents, and adults with moderate-to-severe acne. Half of participants achieved clear/almost clear skin by 12 weeks, rates not previously seen in clinical studies of other topical acne products.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT04214639 and NCT04214652.

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.

Oral Tetracycline-Class Drugs in Dermatology: Impact of Food Intake on Absorption and Efficacy

Tetracycline-class drugs are frequently used in dermatology for their anti-inflammatory properties to treat skin diseases such as acne, rosacea, and hidradenitis suppurativa (HS). The American Academy of Dermatology (AAD) clinical guidelines do not offer guidance regarding the co-administration of food with tetracycline-class drugs. The objectives of this study were to review the available evidence regarding whether taking tetracycline-class drugs with food decreases systemic absorption and is associated with an impact on clinical efficacy. A literature search was conducted using the PubMed database between February to May 2023 using the keywords "tetracycline-class drugs", "pharmacokinetics", "absorption", and "dermatology". Inclusion criteria included articles written in English and relevant to the absorption and efficacy of tetracycline-class drugs. This search yielded 131 articles written between 1977 to 2022, of which 29 met the criteria for review. United States Food and Drug Administration (FDA)-approved prescribing information for oral formulations of tetracycline, doxycycline, minocycline, and sarecycline were reviewed. Systemic absorption of tetracycline decreased when co-administered with food. Systemic absorption of oral doxycycline and minocycline was variable with food co-administration. The impact on bioavailability varied with the drug formulation and dosage. The absorption of oral sarecycline decreased when administered with food. Sarecycline is the only oral antibiotic where population pharmacokinetic studies demonstrated limited or no impact of food intake on clinical efficacy. There are no available data for other tetracycline-class drugs in dermatology. If patients find it more tolerable to take doxycycline, minocycline, and sarecycline with food to avoid gastrointestinal distress, this may merit consideration to encourage patient adherence. Since the impact of food intake on absorption varied with the dosage form of doxycycline and minocycline, consulting the appropriate package insert may give clinicians additional insight into differences in the various formulations.

Ultrasonic Transformation of Antibiotic Molecules into a Selective Chemotherapeutic Nanodrug

Ultrasound-based engineering of carrier-free nanodrugs by supramolecular self-assembly has recently emerged as an innovative and environmentally friendly synthetic approach. By applying high-frequency sound waves (490 kHz) in aqueous solutions, the transformation of small chemotherapeutic and antibiotic drug molecules into carrier-free nanodrugs with anticancer and antimicrobial activities was recently achieved. The transformation of the antibiotic drug molecules, i.e., doxycycline, into stable nanodrugs (~130 nm) with selective anticancer activity was achieved without requiring organic solvents, chemical agents, or surfactants. The obtained nanodrug exhibited reactive oxygen species (ROS)-mediated cytotoxicity on human breast cancer (MDA-MB 231 cells) but a negligible antiproliferative effect on healthy fibroblast cells. Imaging by super-resolution microscopy (STORM) provided insights into the intracellular trafficking and endosomal escape of the nanodrugs. Overall, these findings suggest that small antibiotic drugs can be transformed into chemotherapeutic nanodrugs with high selectivity against cancer cells.

Reduced blood-brain barrier penetration of acne vulgaris antibiotic sarecycline compared to minocycline corresponds with lower lipophilicity

Background

Vestibular side effects such as dizziness and vertigo can be a limitation for some antibiotics commonly used to treat acne, rosacea, and other dermatology indications.

Objective

Unlike minocycline, which is a second-generation tetracycline, sarecycline, a narrow-spectrum third-generation tetracycline-class agent approved to treat acne vulgaris, has demonstrated low rates of vestibular-related adverse events in clinical trials. In this work, we evaluate the brain-penetrative and lipophilic attributes of sarecycline in 2 non-clinical studies and discuss potential associations with vestibular adverse events.

Methods

Rats received either intravenous sarecycline or minocycline (1.0 mg/kg). Blood-brain penetrance was measured at 1, 3, and 6 h postdosing. In another analysis, the lipophilicity of sarecycline, minocycline, and doxycycline was measured via octanol/water and chloroform/water distribution coefficients (logD) at pH 3.5, 5.5, and 7.4.

Results

Unlike minocycline, sarecycline was not detected in brain samples postdosing. In the octanol/water solvent system, sarecycline had a numerically lower lipophilicity profile than minocycline and doxycycline at pH 5.5 and 7.4.

Conclusion

The reduced blood-brain penetrance and lipophilicity of sarecycline compared with other tetracyclines may explain low rates of vestibular-related adverse events seen in clinical trials.

Novel application of a Co-Fermented postbiotics of TYCA06/AP-32/CP-9/collagen in the improvement of acne vulgaris-A randomized clinical study of efficacy evaluation

BACKGROUND

Acne vulgaris is a chronic inflammatory skin disease. If skin lesions are not treated well in time, they can leave a permanent impact on the appearance and a negative influence on personal confidence. The common therapy for acne symptom includes antibiotics, benzoyl peroxide, and azeleic acid. However, those medications have side effects, and the long-term use should be cautious. Therefore, it is necessary to develop a safe and effective material, which is more suitable for daily use.

OBJECTIVE

Collagen was selected to co-ferment with three probiotic strains TYCA06/AP-32/CP-9 (TAC) due to its excellent feature on wound healing. The fermented material was added into cosmetic gel and applied on subjects' acne lesions. The antimicrobial activity against Propionibacterium acnes and anti-inflammation effect around lesion area were investigated in a 4-week clinical study.

MATERIAL AND METHODS

An anti-P. acnes assay, a keratinocytes HaCaT cell-based wound healing assay, and a cytokine assay on thymic stromal lymphopoietin (TSLP) and interleukin (IL)-33 were used to evaluate the function of the fermented material in vitro. The TAC/Collagen formula was further incorporated into a cosmetic gel, and the human clinical trial was carried out by applying this gel on 20 volunteers' face with acne vulgaris. The moisture score, sebum content, inflammation, porphyrins numbers, and brown spot number of whole face were observed and recorded.

RESULTS

The postbiotics of the TAC/Collagen displayed a good growth inhibition against P. acnes and reduced TSLP and IL-33 inflammation in vitro. This TAC/Collagen formula enhanced the wound healing in HaCaT cell culture. The result of the clinical trial showed the TAC/Collagen gel improved the moisture score and inflammation index of the skin in vivo. In addition, this TAC/Collagen gel also improved the wound healing of acne symptom in volunteers with acne vulgaris. Moreover, this TAC/Collagen gel reduced the number of the porphyrins and brown spots on facial skin.

CONCLUSION

These postbiotics of TAC/Collagen have beneficial effects on skin health and are able to ameliorate the redness, inflammation, and acne symptom in acne vulgaris patients.

Profiling the Effects of Systemic Antibiotics for Acne, Including the Narrow-Spectrum Antibiotic Sarecycline, on the Human Gut Microbiota

Treatment for moderate-to-severe acne vulgaris relies on prolonged use of oral tetracycline-class antibiotics; however, these broad-spectrum antibiotics are often associated with off-target effects and negative gastrointestinal sequelae. Sarecycline is a narrow-spectrum antibiotic treatment option. Here, we investigated the effect of prolonged sarecycline exposure, compared with broad-spectrum tetracyclines (doxycycline and minocycline) upon the colonic microbiota. Three in vitro models of the human colon were instilled with either minocycline, doxycycline or sarecycline, and we measured microbiota abundance and diversity changes during and after antibiotic exposure. Significant reductions in microbial diversity were observed following minocycline and doxycycline exposure, which failed to recover post antibiotic withdrawal. Specifically, minocycline caused a ~10% decline in Lactobacillaceae and Bifidobacteriaceae abundances, while doxycycline caused a ~7% decline in Lactobacillaceae and Bacteroidaceae abundances. Both minocycline and doxycycline were associated with a large expansion (>10%) of Enterobacteriaceae. Sarecycline caused a slight decline in bacterial diversity at the start of treatment, but abundances of most families remained stable during treatment. Ruminococcaceae and Desulfovibrionaceae decreased 9% and 4%, respectively, and a transient increased in Enterobacteriaceae abundance was observed during sarecycline administration. All populations recovered to pre-antibiotic levels after sarecycline exposure. Overall, sarecycline had minimal and transient impact on the gut microbiota composition and diversity, when compared to minocycline and doxycycline.

Part I Antimicrobial resistance: Bacterial pathogens of dermatologic significance and implications of rising resistance

Although the COVID-19 pandemic has been the defining global health crisis of our time, public health officials have been sounding the alarm of another ominous threat for years: an impending antimicrobial resistance crisis. In dermatology, antibiotics are often used for prolonged courses in the treatment of skin and soft tissue infections and common inflammatory skin conditions, increasing the risk of microbiome alteration and antibiotic-related adverse effects, all while exerting consequential selective pressures on both pathogenic and bystander bacteria. In this review, we hope to raise awareness of the crisis of antimicrobial resistance and review resistance concerns related to dermatology-relevant bacterial pathogens.

Sarecycline Demonstrates Clinical Effectiveness against Staphylococcal Infections and Inflammatory Dermatoses: Evidence for Improving Antibiotic Stewardship in Dermatology

Tetracycline class antibiotics are widely used for multiple skin diseases, including acne vulgaris, acne rosacea, cutaneous infections, inflammatory dermatoses, and autoimmune blistering disorders. Concerns about antibiotic resistance and protecting the human/host microbiome beg the question whether broad-spectrum tetracyclines such as doxycycline and minocycline should be prescribed at such a high rate by dermatologists when a narrow-spectrum tetracycline derivative, sarecycline, exists. We evaluated the clinical effectiveness of oral sarecycline against cutaneous staphylococcal infections, eyelid stye, and mucous membrane pemphigoid to determine whether sarecycline is a viable option for clinicians to practice improved antibiotic stewardship. We observed significant improvement in staphylococcal infections and inflammatory dermatoses with courses of oral sarecycline as short as 9 days, with no reported adverse events. These clinical findings are consistent with in vitro microbiological data and anti-inflammatory properties of sarecycline. Our data provides a strong rationale for clinicians to use narrow-spectrum sarecycline rather than broad-spectrum tetracyclines as a first-line agent in treating staphylococcal skin infections and inflammatory skin diseases for which tetracyclines are currently commonly employed. Such advancement in the practice paradigm in dermatology will enhance antibiotic stewardship, reduce risk of antibiotic resistance, protect the human microbiome, and provide patients with precision medicine care.

Sonosynthesis of nanobiotics with antimicrobial and antioxidant properties

Transforming small-molecule antibiotics into carrier-free nanoantibiotics represents an opportunity for developing new multifunctional therapeutic agents. In this study, we demonstrate that acoustic cavitation produced by high-frequency ultrasound transforms the antibiotic doxycycline into carrier-free nanobiotics. Upon sonication for 1 h at 10-15 W cm^-3, doxycycline molecules underwent hydroxylation and dimerization processes to ultimately self-assemble into nanoparticles of ∼100-200 nm in size. Micrometer sized particles can be also obtained by increasing the acoustic power to 20 W cm^-3. The nanodrugs exhibited antioxidant properties, along with antimicrobial activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacterial strains. Our results highlight the feasibility of the ultrasound-based approach for engineering drug molecules into a nanosized formulation with controlled and multiple bio-functionalities.

Discovery and Development of Antibacterial Agents: Fortuitous and Designed

Today, antibacterial drug resistance has turned into a significant public health issue. Repeated intake, suboptimal and/or unnecessary use of antibiotics, and, additionally, the transfer of resistance genes are the critical elements that make microorganisms resistant to conventional antibiotics. A substantial number of antibacterials that were successfully utilized earlier for prophylaxis and therapeutic purposes have been rendered inadequate due to this phenomenon. Therefore, the exploration of new molecules has become a continuous endeavour. Many such molecules are at various stages of investigation. A surprisingly high number of new molecules are currently in the stage of phase 3 clinical trials. A few new agents have been commercialized in the last decade. These include solithromycin, plazomicin, lefamulin, omadacycline, eravacycline, delafloxacin, zabofloxacin, finafloxacin, nemonoxacin, gepotidacin, zoliflodacin, cefiderocol, BAL30072, avycaz, zerbaxa, vabomere, relebactam, tedizolid, cadazolid, sutezolid, triclosan and afabiacin. This article aims to review the investigational and recently approved antibacterials with a focus on their structure, mechanisms of action/resistance, and spectrum of activity. Delving deep, their success or otherwise in various phases of clinical trials is also discussed while attributing the same to various causal factors.

The Development of Third-Generation Tetracycline Antibiotics and New Perspectives

The tetracycline antibiotic class has acquired new valuable members due to the optimisation of the chemical structure. The first modern tetracycline introduced into therapy was tigecycline, followed by omadacycline, eravacycline, and sarecycline (the third generation). Structural and physicochemical key elements which led to the discovery of modern tetracyclines are approached. Thus, several chemical subgroups are distinguished, such as glycylcyclines, aminomethylcyclines, and fluorocyclines, which have excellent development potential. The antibacterial spectrum comprises several resistant bacteria, including those resistant to old tetracyclines. Sarecycline, a narrow-spectrum tetracycline, is notable for being very effective against Cutinebacterium acnes. The mechanism of antibacterial action from the perspective of the new compound is approached. Several severe bacterial infections are treated with tigecycline, omadacycline, and eravacycline (with parenteral or oral formulations). In addition, sarecycline is very useful in treating acne vulgaris. Tetracyclines also have other non-antibiotic properties that require in-depth studies, such as the anti-inflammatory effect effect of sarecycline. The main side effects of modern tetracyclines are described in accordance with published clinical studies. Undoubtedly, this class of antibiotics continues to arouse the interest of researchers. As a result, new derivatives are developed and studied primarily for the antibiotic effect and other biological effects.

A Review of Systemic Minocycline Side Effects and Topical Minocycline as a Safer Alternative for Treating Acne and Rosacea

Resistance of Cutibacterium acnes to topical antibiotics historically used to treat acne (topical erythromycin and clindamycin and, more recently, topical azithromycin and clarithromycin) has been steadily increasing and new topical antibiotics are needed. Minocycline is a semisynthetic tetracycline-derived antibiotic currently used systemically to treat a wide range of infections caused by Gram-negative and Gram-positive bacteria. In addition to its antibiotic activity, minocycline possesses anti-inflammatory properties, such as the downregulation of proinflammatory cytokine production, suppression of neutrophil chemotaxis, activation of superoxide dismutase, and inhibition of phagocytosis, among others. These characteristics make minocycline a valuable agent for treatment of dermatological diseases such as acne vulgaris and papulopustular rosacea. However, more frequent or serious adverse effects have been observed upon the systemic administration of minocycline than with other tetracyclines. Examples of serious adverse effects include hypersensitivity syndrome reaction, drug-induced lupus, idiopathic intracranial hypertension, and other autoimmune syndromes that may cause death. Here, we review adverse effects and drug–drug interactions observed with oral administration of minocycline and contrast this with topical minocycline formulations recently approved or under development for effectively treating dermatological disorders with fewer adverse effects and less drug interaction.