Similarities and differences between doxycycline and minocycline: clinical and antimicrobial stewardship considerations

Comparing the clinical effects of local administration of minocycline ointment and doxycycline solution in the treatment of acute periodontal abscesses: a retrospective clinical study

PURPOSE

The objective of this retrospective clinical study was to provide evidence supporting the adjunctive local application of doxycycline solution or minocycline ointment, in conjunction with drainage, for the treatment of acute periodontal abscesses.

METHODS

The study included 63 patients who had received treatment for acute periodontal abscesses through drainage supplemented with 1 of 3 types of adjunctive medications during their initial visit (visit 1; baseline): 1) saline irrigation (the control group), 2) 2% minocycline ointment (the TM group), or 3) 300 mg/mL doxycycline irrigation (the TD group). The same adjunctive medication was administered at visit 2, which took place 1 week after visit 1. Probing depth (PD), bleeding on probing (BOP), plaque index, gingival recession, clinical attachment level, and tooth mobility were clinically evaluated at visits 1, 2, and a third visit (visit 3; 4 weeks after visit 1). Statistical significance was considered to be indicated by P values <0.05.

RESULTS

By visit 3, all clinical indices and tooth mobility had significantly decreased in each group. At this visit, PD and BOP on the abscess side were significantly lower in the TM and TD groups compared to the control group. The TD group showed a significantly greater improvement than the TM group, with mean PD reductions of 1.09 mm in the control group, 1.88 mm in the TM group, and 2.88 mm in the TD group. Similarly, mean BOP reductions were 45% in the control group, 73.02% in the TM group, and 95.45% in the TD group.

CONCLUSIONS

Local and adjunctive administration of doxycycline and minocycline in combination with drainage exhibited clinical advantages over drainage alone in improving PD and BOP. Notably, a doxycycline solution of 300 mg/mL was more effective than a 2% minocycline ointment.

Oral doxycycline to carbapenem-resistant Acinetobacter baumannii infection as a polymyxin-sparing strategy: results from a retrospective cohort

Acinetobacter baumannii infection presents a high mortality rate and few therapeutic options. This study aimed to evaluate clinical-microbiological characteristics and prognosis factors of patients diagnosed with A. baumanni. infections treated with oral doxycycline. A retrospective cohort of hospitalized patients with confirmed Acinetobacter spp. infection between 2018 and 2020 receives at least 3 days of oral doxycycline. Clinical and microbiological data were evaluated, including the outcome and molecular characterization of A. baumannii. Doxycycline minimal inhibitory concentrations were evaluated by the broth dilution method. One hundred patients were included with a median age of 51 years. The leading site of infection was pulmonary (n = 62), followed by the soft tissues and skin (n = 28). A. baumannii resistant to carbapenem was found on 94%. The gene blaOXA-23 and blaOXA-51 were amplified in all recovered isolates of A. baumannii (n = 44). Doxycycline MIC50 and MIC90 were 1 µg/mL and 2 µg/mL, respectively. Death rate at 14 days and 28 days of follow-up was 9% and 14%, respectively. The prognostic factors related to death at end of follow-up were age > 49 years [85.7% vs. 46%, CI 95% 6.9 (1.4-32.6), P = 0.015] and hemodialysis [28.6% vs. 7%, CI 95% 5.33 (1.2-22.1), P = 0.021]. Patients treated with doxycycline to A. baumannii presented a relatively low death rate, and risk factors related to death were age and hemodialysis. Further and larger studies should compare polymyxin to doxycycline to better understand the differences between these therapeutic options.

Acute bacterial skin and skin structure infections in pediatric patients: potential role of dalbavancin

INTRODUCTION

Acute bacterial skin and skin structure infections (ABSSSIs) are a subtype of skin and soft tissue infections (SSTI), usually sustained by Gram-positive bacteria, whose incidence is high among children. ABSSSIs are responsible for a considerable number of hospitalizations. Moreover, as multidrug resistant (MDR) pathogens become widespread, the pediatric category seems burdened with an increased risk of resistance and treatment failure.

AREAS COVERED

To obtain a view on the status of the field, we describe the clinical, epidemiological, and microbiological aspects of ABSSSI in children. Old and new treatment options were critically revised with a focus on the pharmacological characteristics of dalbavancin. Evidence on the use of dalbavancin in children was collected, analyzed, and summarized.

EXPERT OPINION

Many of the therapeutic options available at the moment are characterized by the need for hospitalization or repeated intravenous infusions, safety issues, possible drug-drug interactions, and reduced efficacy on MDRs. Dalbavancin, the first long-acting molecule with strong activity against methicillin-resistant and also many vancomycin-resistant pathogens represents a game changer for adult ABSSSI. In pediatric settings, the available literature is still limited, but a growing body of evidence supports dalbavancin use in children with ABSSSI, demonstrating this drug to be safe and highly efficacious.

A Recent Update on Pathophysiology and Therapeutic Interventions of Alzheimer's Disease

AIM

Alzheimer's disease (AD) has been identified as a progressive brain disorder associated with memory dysfunction and the accumulation of β-amyloid plaques and neurofibrillary tangles of τ protein. Mitochondria is crucial in maintaining cell survival, cell death, calcium regulation, and ATP synthesis. Mitochondrial dysfunction and linked calcium overload have been involved in the pathogenesis of AD. CRM2 (Collapsin response mediator protein-2) is involved in endosomal lysosomal trafficking as well as autophagy, and their reduced level is also a primary culprit in the progression of AD. In addition, Cholinergic neurotransmission and neuroinflammation are two other mechanisms implicated in AD onset and might be protective targets to attenuate disease progression. The microbiota-gut-brain axis (MGBA) is another crucial target for AD treatment. Crosstalk between gut microbiota and brain mutually benefitted each other, dysbiosis in gut microbiota affects the brain functions and leads to AD progression with increased AD-causing biomarkers. Despite the complexity of AD, treatment is only limited to symptomatic management. Therefore, there is an urgent demand for novel therapeutics that target associated pathways responsible for AD pathology. This review explores the role of different mechanisms involved in AD and possible therapeutic targets to protect against disease progression.

BACKGROUND

Amidst various age-related diseases, AD is the most deleterious neurodegenerative disorder that affects more than 24 million people globally. Every year, approximately 7.7 million new cases of dementia have been reported. However, to date, no novel disease-modifying therapies are available to treat AD.

OBJECTIVE

The aim of writing this review is to highlight the role of key biomarker proteins and possible therapeutic interventions that could play a crucial role in mitigating the ongoing prognosis of Alzheimer's disease.

MATERIALS AND METHODS

The available information about the disease was collected through multiple search engines, including PubMed, Science Direct, Clinical Trials, and Google Scholar.

RESULTS

Accumulated pieces of evidence reveal that extracellular aggregation of β-amyloid plaques and intracellular tangles of τ protein are peculiar features of perpetuated Alzheimer's disease (AD). Further, the significant role of mitochondria, calcium, and cholinergic pathways in the pathogenesis of AD makes the respiratory cell organelle a crucial therapeutic target in this neurodegenerative disease. All currently available drugs either delay the clinical damage to cells or temporarily attenuate some symptoms of Alzheimer's disease.

CONCLUSION

The pathological features of AD are extracellular deposition of β-amyloid, acetylcholinesterase deregulation, and intracellular tangles of τ protein. The multifactorial heterogeneity of disease demands more research work in this field to find new therapeutic biological targets.

Omadacycline Is Highly Active In Vitro against Mycoplasma genitalium

Here, we performed in vitro susceptibility testing on 10 Mycoplasma genitalium isolates against omadacycline, minocycline, tetracycline, doxycycline, moxifloxacin, levofloxacin, and azithromycin. Omadacycline was the most potent agent, with all MICs of ≤0.5 μg/mL. MICs were not affected by resistance to other agents, including resistance to other tetracycline class drugs. Omadacycline may be a potential treatment option for M. genitalium infection. IMPORTANCE There are very few clinical isolates of Mycoplasma genitalium available for in vitro susceptibility testing. We studied 10 isolates and determined that the new semisynthetic aminomethylcycline omadacycline is active against isolates that are resistant to tetracyclines, macrolides, and quinolones. These data suggest that clinical studies should be performed in order to see if omadacycline may be useful to treat urogenital infections caused by M. genitalium.

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.

Cold Agglutinins and Cryoglobulins Associate With Clinical and Laboratory Parameters of Cold Urticaria

Mast cell-activating signals in cold urticaria are not yet well defined and are likely to be heterogeneous. Cold agglutinins and cryoglobulins have been described as factors possibly associated with cold urticaria, but their relevance has not been explained. We performed a single-center prospective cohort study of 35 cold urticaria patients. Cold agglutinin and cryoglobulin test results, demographics, detailed history data, cold stimulation test results, complete blood count values, C-reactive protein, total immunoglobulin E levels, and basal serum tryptase levels were analyzed. Forty six percent (n = 16) of 35 tested patients had a positive cold agglutinin test and 27% (n = 9) of 33 tested patients had a positive cryoglobulin test. Cold agglutinin positive patients, when compared to cold agglutinin negative ones, were mainly female (P = 0.030). No gender-association was found for cryoglobulins. A positive cold agglutinin test, but not a positive cryoglobulin test, was associated with a higher rate of reactions triggered by cold ambient air (P = 0.009) or immersion in cold water (P = 0.041), and aggravated by increased summer humidity (P = 0.007). Additionally, patients with a positive cold agglutinin test had a higher frequency of angioedema triggered by ingestion of cold foods or drinks (P = 0.043), and lower disease control based on Urticaria Control Test (P = 0.023). Cold agglutinin levels correlated with erythrocyte counts (r = −0.372, P = 0.028) and monocyte counts (r = −0.425, P = 0.011). Cryoglobulin concentrations correlated with basal serum tryptase levels (r = 0.733, P = 0.025) and cold urticaria duration (r = 0.683, P = 0.042). Results of our study suggest that cold agglutinins and cryoglobulins, in a subpopulation of cold urticaria patients, are linked to the course and possibly the pathogenesis of their disease.

Antibacterial Collagen Composite Membranes Containing Minocycline

Collagen membranes have been used as bioresorbable barrier membranes in guided tissue/bone regeneration. However, the collagen membranes currently used in clinics lack an active antibacterial function, although infection at surgical sites presents a realistic challenge for guided tissue/bone regeneration. In this study, we successfully prepared novel and advanced collagen composite membranes from collagen and complexes of heparin and chelates of minocycline and Ca²⁺ ions. These membranes were characterized for chemical structures, morphology, elemental compositions and tensile strength. In vitro release studies were conducted to evaluate the release kinetics of minocycline from these membranes. Agar disk diffusion assays were used to assess their sustained antibacterial capability against model pathogenic bacteria Staphylococcus aureus. The chemical and physical characterization confirmed the successful synthesis of minocycline-loaded collagen composite membranes, namely NCCM-1 and NCCM-2. Both membranes had weaker tensile strength as compared with commercial collagen membranes. They achieved sustained release of minocycline for at least 4 weeks in simulated body fluid (pH 7.4) at 37°C. Moreover, both membranes demonstrated potent sustained antibacterial effects against Staphylococcus aureus. These results suggested that the advanced collagen composite membranes containing minocycline can be exploited as novel guided tissue regeneration membranes or wound dressing by providing additional antibacterial functions.

Use of Oral Tetracyclines in the Treatment of Adult Patients with Community-Acquired Bacterial Pneumonia: A Literature Review on the Often-Overlooked Antibiotic Class

Oral tetracyclines have been used in clinical practice for over 60 years. Overall, one of the most common indications for use of oral tetracyclines is for treatment of adult outpatients with lower respiratory tract infections, including community-acquired pneumonia (CAP). Despite the longstanding use of oral tetracyclines, practice patterns indicate that they are often considered after other guideline-concordant oral CAP treatment options (namely macrolides, fluoroquinolones, and β-lactams). However, there are growing resistance or safety concerns with the available oral agents listed for outpatients with CAP in the updated American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) CAP guidelines, especially among patients with comorbidities or notable risk factors for resistant pathogens. Given the need for alternative oral agents to macrolides, fluoroquinolones, and beta-lactams for adult outpatients with CAP, this review summarizes the literature on the use of oral tetracyclines (i.e., doxycycline, minocycline, and omadacycline) for this indication. As part of this review, we described their mechanism of action, common mechanisms of resistance, susceptibility profiles against common CAP pathogens, pharmacokinetics, pharmacodynamics, clinical data, and safety. The intent of the review is to highlight the important considerations when deciding between doxycycline, minocycline, and omadacycline for an adult outpatient with CAP in situations in which use of an oral tetracycline is warranted.

Azithromycin combined with doxycycline in non-gonococcal urethritis

Non-gonococcal urethritis (NGU) is one of the most common sexually transmitted diseases caused by chlamydia or mycoplasma. The present study aimed to explore the clinical efficacy of azithromycin combined with doxycycline in patients with NGU and its effect on serum levels of inflammatory cytokine interleukin-6 (IL-6). A total of 98 patients with non-gonococcal urethritis were prospectively selected, of which 46 patients were assigned to an azithromycin group (treated with azithromycin alone), while the rest were assigned to a combination group (treated with azithromycin and doxycycline). The conditions of the patients were evaluated and compared between the two groups. The treatment efficacy in patients in the combination group was significantly better than that in the azithromycin group, and the time to symptom relief, period of medication, recurrence rate within 1 year of withdrawal and level of serum IL-6 in the combination group were significantly lower than those in the azithromycin group. The quality of life of patients in the combination group was significantly improved compared to those in the azithromycin group. However, there was no significant difference in the incidence of adverse reactions between the two groups. Azithromycin combined with doxycycline was revealed to be more effective than azithromycin monotherapy for NGU.

Sarecycline: A Review of Preclinical and Clinical Evidence

Sarecycline is a tetracycline-derived oral antibiotic, specifically designed for acne, and is approved by the Food and Drug Administration (FDA) in 2018 for the treatment of inflammatory lesions of non-nodular moderate to severe acne vulgaris (AV) in patients 9 years of age and older. It has been decades since a novel systemic antibiotic was approved to treat AV, a disease that affects up to 90% of teenagers and young adults worldwide and lasts well into adulthood. Sarecycline holds promise to yield fewer side effects than other commonly used broad-spectrum tetracyclines, including minocycline and doxycycline. The narrower spectrum of antibacterial activity of sarecycline, which specifically targets C. acnes and some Gram-positive bacteria with little or no activity against Gram-negative bacteria, suggests not only the potential for reduced emergence of antibiotic-resistant bacterial strains but also less disruption of the human gut microflora. Here, we review the key preclinical and clinical evidence on sarecycline.

Differential effects of minocycline on microvascular complications in murine models of type 1 and type 2 diabetes

Diabetes is a global healthcare problem associated with enormous healthcare and personal costs. Despite glucose lowering agents that control glycaemia, both type 1 (T1D) and type (T2D) diabetes patients often develop microvascular complications that increase morbidity and mortality. Current interventions rely on careful glycemic control and healthy lifestyle choices, but these are ineffective at reversing or completely preventing the major microvascular complications, diabetic peripheral neuropathy (DPN), diabetic retinopathy (DR), and diabetic kidney disease (DKD). Minocycline, a tetracycline antibiotic with anti-inflammatory and anti-apoptotic properties, has been proposed as a protective agent in diabetes. However, there are no reported studies evaluating the therapeutic efficacy of minocycline in T1D and T2D models for all microvascular complications (DPN, DR, and DKD). Therefore, we performed metabolic profiling in streptozotocin-induced T1D and db/db T2D models and compared the efficacy of minocycline in preventing complications to that of insulin and pioglitazone in both models. Minocycline partially ameliorated DR and DKD in T1D and T2D animals, but was less effective than insulin or pioglitazone, and failed to improve DPN in either model. These results suggest that minocycline is unlikely to improve outcomes beyond that achieved with current available therapies in patients with T1D or T2D associated microvascular complications.

Minocycline, focus on mechanisms of resistance, antibacterial activity, and clinical effectiveness: Back to the future

OBJECTIVES

The increasing crisis regarding multidrug-resistant (MDR) and extensively drug-resistant microorganisms leads to appealing therapeutic options.

METHODS

During the last 30 years, minocycline, a wide-spectrum antimicrobial agent, has been effective against MDR Gram-positive and Gram-negative bacterial infections. As with other tetracyclines, the mechanism of action of minocycline involves attaching to the bacterial 30S ribosomal subunit and preventing protein synthesis.

RESULTS

This antimicrobial agent has been approved for the treatment of acne vulgaris, some sexually transmitted diseases and rheumatoid arthritis. Although many reports have been published, there remains limited information regarding the prevalence, mechanism of resistance and clinical effectiveness of minocycline.

CONCLUSION

Thus, we summarize here the currently available data concerning pharmacokinetics and pharmacodynamics, mechanism of action and resistance, antibacterial activity and clinical effectiveness of minocycline.

Cytotoxic and proapoptotic effect of doxycycline - An in vitro study on the human skin melanoma cells

Doxycycline is a semisynthetic, second generation tetracycline. Currently, it is used, among others, in the treatment of acne and skin infections. Moreover, doxycycline has many valuable nonantibiotic properties, including anti-inflammatory, immunosuppressive and anticancer effects. Recent studies showed that the drug had the ability to inhibit the adhesion and migration of cancer cells, as well as affected their growth and proliferation and induced apoptosis. The purpose of this study was to examine the antimelanoma effect of doxycycline. The obtained results demonstrated that doxycycline decreased the viability and inhibited the proliferation of human melanoma cells, proportionally to the drug concentration and the treatment time. It was stated that doxycycline disturbed the homeostasis of the cells by lowering intracellular level of reduced thiols. In addition, the treatment changed the cell cycle profile and triggered the DNA fragmentation. Mitochondria of melanoma cells exposed to the drug had lowered membrane potential, which indicated cells apoptosis. Finally, doxycycline induced the externalization phosphatidylserine - a well-known hallmark of apoptosis, confirmed by results of annexin V test. The presented study contributes to the increase of knowledge about nonantibacterial action of doxycycline, including the influence on human cancer cells and indicates new potential possibility of effective treatment of malignant melanoma.

Antibiotic Stewardship Program Perspective: Oral Antibiotic Therapy for Common Infectious Diseases

Traditionally, initial antibiotic therapy was administered intravenously (IV). Over the past 3 decades, there has been increased understanding, appreciation, and application of pharmacokinetic (PK) and pharmacodynamic (PD) principles in antibiotic therapy. The utilization of PK/PD parameters as applied to antimicrobial therapy has led to optimizing dosage regimens as well as increased awareness and experience with oral versus antibiotic therapy. When an oral antibiotic, given at the same dose as its IV formulation, results in the same serum/tissue levels, then oral antibiotics should be used whenever possible. When chosen carefully, oral therapy provides many benefits over IV therapy.

Induction of Different Sensitization Patterns of MRSA to Antibiotics Using Electroporation

Treatment of bacteria-associated infections is complicated and antibiotic treatment alone is often inadequate to overcome biofilm infections. Physical methods allow overcoming this problem and propose solutions that are non-dependent on drug resistance. In this work, we investigated the feasibility of pulsed electric fields for sensitization of MRSA to common antibiotics. We analyzed the efficacy of inactivation of methicillin-resistant Staphylococcus aureus in 5–20 kV/cm electric field separately and in combination with gentamicin, doxycycline, ciprofloxacin, sulfamethoxazole, and vancomycin. Combined treatment allowed using up to 1000-fold smaller concentrations of antibiotics to induce the same inactivation of S. aureus.