Tigecycline-Induced Tooth Discoloration in Children Younger than Eight Years

Anti-bacteria, anti-biofilm, and anti-virulence activity of the synthetic compound MTEBT-3 against carbapenem-resistant Klebsiella pneumoniae strains ST3984

PURPOSE

The rise of carbapenem-resistant Klebsiella pneumoniae (CRKP) has led to increased morbidity and mortality in clinical patients, highlighting the urgent need for effective antibacterial agents.

METHODS

We obtained a synthetic compound, MTEBT-3, using hydrophobic triphenylamine as the skeleton and hydrophilic ammonium salts. We determined the MIC of MTEBT-3 using the macro-broth susceptibility testing method. We isolated a clinical CRKP strain ST3984 and performed synergistic antibiotic sensitivity tests, time-kill assays, and resistance evolution studies. Biofilm formation under sub-MIC conditions was evaluated using crystal violet staining and CLSM. Additionally, biofilm proteins and polysaccharides were quantified. We assessed the bactericidal mechanism of MTEBT-3 by examining the integrity of CRKP bacterial cell membranes and analyzing the transcription of virulence-regulating genes via quantitative real-time PCR.

RESULTS

MTEBT-3 exhibited broad-spectrum antibacterial activity with a low resistance rate, achieving an MIC of 8 μg/mL. The compound displayed additive effects with meropenem and imipenem and synergistic effects with tigecycline. It maintained its efficacy over multiple bacterial generations, with no significant increase in resistance observed. Under sub-MIC conditions, the biomass of biofilms was significantly reduced, and the levels of proteins and polysaccharides within the biofilms were markedly lowered in a concentration-dependent manner. The bactericidal mechanism of MTEBT-3 involved disrupting the integrity of CRKP bacterial cell membranes, leading to increased permeability. Quantitative real-time PCR results showed that MTEBT-3 effectively suppressed the expression of key virulence genes, including fimH, wbbM, rmpA, and rmpA2, which are associated with biofilm formation and bacterial adhesion.

CONCLUSION

The significant antimicrobial activity of MTEBT-3 against clinically isolated CRKP, along with its synergistic or additive effects with commonly used antibiotics, positions it as a promising candidate for treatment. Its ability to disrupt biofilm formation and reduce virulence factor expression further underscores its potential in managing CRKP infections.

Safety profiles of tetracycline-class drugs: a pharmacovigilance analysis of the FAERS database

BACKGROUND

As synthesis technology advances, novel and efficient derivatives of tetracyclines are found. Three new antibiotics were approved within the past 18 years, and represent a new era in the use of tetracyclines. To gain further insight into adverse events linked to tetracyclines and better protect pediatric patients, ongoing monitoring of safety data is crucial.

METHODS

The FAERS data from the first quarter of 2004 to the third quarter of 2023 in the AERSMine were extracted to conduct disproportionality analysis. The association between five tetracyclines and adverse events was evaluated using reporting odds ratio, and their risk factors were explored by multivariate logistic regression analysis.

RESULTS

Our study showed that thyroid gland disorders had the strongest signal in children. Patients aged 12-18 and treatment with minocycline are risk factors for thyroid adverse events (12-18: OR = 10.727 [7.113-16.177], p < 0.0001; minocycline: OR = 17.025 [10.475-27.678], p < 0.0001). Second-generation tetracycline and third-generation tetracycline ADR patterns differed. Blood fibrinogen decreased and hypofibrinogenaemia was primarily reported with tigecycline and eravacycline.

CONCLUSION

This study provided basic evidence for further research on tetracyclines-related adverse events. However, the safety of third-generation tetracycline in children requires additional validation through a large-scale prospective study.

Safety profiles of doxycycline, minocycline, and tigecycline in pediatric patients: a real-world pharmacovigilance analysis based on the FAERS database

Introduction

Recently, the rise of antibiotic resistance has prompted a reconsideration of tetracyclines. However, existing studies are inadequate in assessing the pediatric safety of this class of antibiotics. To address the gap, our study aims to comprehensively assess the safety of tetracyclines in children.

Methods

Adverse event (AE) reports from January 2005 to September 2023 were obtained from the U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database, and reporting odds ratio (ROR) was performed to identify potential risk signals in children under 18 years old who were administered any of the three tetracyclines: doxycycline, minocycline, and tigecycline.

Results

A total of 1903 AE cases were included in our study: 782 for doxycycline, 981 for minocycline, and 140 for tigecycline. Doxycycline and tigecycline were predominantly associated with "general disorders and administration site conditions" and "gastrointestinal disorders," while minocycline was more frequently linked to "skin and subcutaneous tissue disorders" and "gastrointestinal disorders." Psychiatric risks predominantly included depression, suicidal ideation, and suicide attempt. In the category of skin and subcutaneous tissues, 30.88% of the minocycline-induced drug reaction with eosinophilia and systemic symptoms (DRESS) cases resulted in death, alongside a high occurrence of co-occurring AEs such as multiple organ dysfunction syndrome, Type 1 Diabetes Mellitus (T1DM), and autoimmune thyroiditis. As for the endocrine system, both doxycycline and minocycline were found to potentially increase the risk of thyroid dysfunction. For children under the age of 8, doxycycline was associated with tooth discoloration (N = 7, ROR = 20.11%, 95% CI: 9.48-42.67), although it remained unclear whether the discoloration was permanent.

Conclusion

Our findings indicated that for pediatric patients, the majority of results were in line with the prescribing information and previous studies, and minocycline tended to cause more frequent and severe AEs than doxycycline. However, it is noteworthy that exceptions were found for psychiatric disorders and thyroid dysfunction associated with doxycycline, which are not mentioned in its FDA prescribing information. Additionally, further safety studies on tigecycline are still needed for children. When prescribing tetracyclines to pediatric patients, a careful risk-benefit assessment is crucial.

Real-world safety profile of tetracyclines in children younger than 8 years old: an analysis of FAERS database and review of case report

BACKGROUND

The study aims to obtain the real-world safety profile of tetracyclines in children younger than 8 years old and provide reference for clinical drug applications.

RESEARCH DESIGN AND METHODS

We made a disproportionality analysis of the FDA Adverse Event Reporting System (FAERS) database through OpenVigil 2 and conducted a review of case reports regarding adverse drug reactions (ADRs) of tetracyclines in children younger than 8-year-old.

RESULTS

FAERS analysis identified 32 ADRs of tetracyclines in children younger than 8-year-old. Respiratory, thoracic, and mediastinal disorders contained the most frequent ADRs among all system organ classes (SOCs). The top three positive signals with the highest proportional reporting ratio (PRR) were laryngeal injury, Horner's syndrome and methaemoglobinaemia. Sixteen published tetracyclines-associated cases in children younger than 8-year-old were identified in the literature, concentrating in three SOCs. Gastrointestinal disorders were the most commonly reported cases (n = 12).

CONCLUSIONS

Several ADRs were newly reported only in children younger than 8-year-old in our research, including Horner's syndrome and methemoglobinemia. We recommended that the clinical practitioners should pay attention to the ADRs both in instruction and beyond the label. Take close care of children and timely intervene when the treatment is inevitable.

Emergence of ceftazidime-avibactam resistance in blaKPC-33-harbouring ST11 Klebsiella pneumoniae in a paediatric patient

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses immense threats to the health of infected patients worldwide, especially children. This study reports the infection caused by CRKP in a paediatric intensive care unit (PICU) child and its drug-resistant mutation during the treatment. Twelve Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae strains were isolated from the child. Broth microdilution method, plasmid transformation assay, and whole genome sequencing (WGS) were performed to investigate the antimicrobial susceptibility, resistance mechanisms, and genetic structural features of CRKPs. The results showed that 12 strains were highly resistant to most available antimicrobial agents. Among them, K. pneumoniae FD11 and K. pneumoniae FD12 were resistant to ceftazidime-avibactam (CZA, MIC >64 mg/L) and restored the carbapenem susceptibility (Imipenem, MIC =0.25 mg/L; Meropenem, MIC =2 mg/L). The patient improved after treatment with CZA in combination with aztreonam. Plasmid transformation assay demonstrated that the blaKPC-33-positive transformant increased MICs of CZA by at least 33-fold and 8-fold compared with the recipient Escherichia coli DH5α and blaKPC-2-positive transformants. WGS analysis revealed that all strains belonged to the ST11-KL64 type and showed highly homologous (3-26 single nucleotide polymorphisms [SNPs]). A single base mutation (G532T) of blaKPC-2 resulted in a tyrosine to aspartic acid substitution at Ambler amino acid position 179 (D179Y), which conferred CZA resistance in K. pneumoniae. This is the first report of a drug-resistant mutation evolving into blaKPC-33 during the treatment of blaKPC-2-positive CRKP in paediatric-infected patients. It advises clinicians that routine sequential antimicrobial susceptibility testing and KPC genotyping are critical during CZA therapy in children infected with CRKP.

Citric acid-modified pH-sensitive bone-targeted delivery of estrogen for the treatment of postmenopausal osteoporosis

Bone targeted delivery of estrogen offers great promise for the clinical application of estrogen in the treatment of postmenopausal osteoporosis (PMOP). However, the current bone-targeted drug delivery system still has several issues that need to be solved, such as the side effects of bone-targeted modifier molecules and the failure of the delivery system to release rapidly in the bone tissue. It is important to aggressively search for new bone-targeted modifier molecules and bone microenvironment-responsive delivery vehicles. Inspired by the distribution of citric acid (CA) mainly in bone tissue and the acidic bone resorption microenvironment, we constructed a CA-modified diblock copolymer poly(2-ethyl-2-oxazoline)-poly(ε-caprolactone) (CA-PEOz) drug delivery system. In our study, we found that the CA modification significantly increased the bone targeting of this drug delivery system, and the delivery system was able to achieve rapid drug release under bone acidic conditions. The delivery system significantly reduced bone loss in postmenopausal osteoporotic mice with a significant reduction in estrogenic side effects on the uterus. In summary, our study shows that CA can act as an effective bone targeting modifier molecule and provides a new option for bone targeting modifications. Our study also provides a new approach for bone-targeted delivery of estrogen for the treatment of PMOP.

Use of Newer and Repurposed Antibiotics against Gram-Negative Bacteria in Neonates

Antimicrobial resistance has become a significant public health problem globally with multidrug resistant Gram negative (MDR-GN) bacteria being the main representatives. The emergence of these pathogens in neonatal settings threatens the well-being of the vulnerable neonatal population given the dearth of safe and effective therapeutic options. Evidence from studies mainly in adults is now available for several novel antimicrobial compounds, such as new β-lactam/β-lactamase inhibitors (e.g., ceftazidime-avibactam, meropenem-vaborbactam, imipenem/cilastatin-relebactam), although old antibiotics such as colistin, tigecycline, and fosfomycin are also encompassed in the fight against MDR-GN infections that remain challenging. Data in the neonatal population are scarce, with few clinical trials enrolling neonates for the evaluation of the efficacy, safety, and dosing of new antibiotics, while the majority of old antibiotics are used off-label. In this article we review data about some novel and old antibiotics that are active against MDR-GN bacteria causing sepsis and are of interest to be used in the neonatal population.

Engineered Plant Virus Complexes with a RANK Motif Modulator and Bone Targeting for Osteoporosis Treatment

Osteoporosis is a systemic skeletal disorder characterized by excessive osteoclastic bone resorption and impaired osteoblastic bone formation. Traditional delivery of antiresorptive drugs lacks a specific biodistribution in the body and may cause adverse effects to the patients. In this study, the peptide BTRM is first synthesized consisting of the bone-targeting peptide Asp8 (BT) and the peptide derived from the amino acid sequences of RANK Motif2/3 (RM), two cytoplasmic RANK motifs (PVQEET^560-565 and PVQEQG^604-609) that have been reported to play an important role in osteoclastogenesis. Then, BTRM is conjugated on the plant virus-like nanoparticles (VNPs) obtained from cowpea chlorotic mottle viruses (CCMVs), forming the engineered plant viruses BTRM-VNPs. In vitro experiments demonstrate that BTRM-VNPs can effectively and safely inhibit osteoclast differentiation and function. Moreover, after injection into ovariectomized mice, BTRM-VNPs show excellent capability to target bone tissue and improve osteoporotic bone loss. Collectively, the findings may provide a novel and promising strategy in the treatment of osteoporotic defects via targeting bone tissue and regulating the function of RANK Motif2/3.

Drug-induced tooth discoloration: An analysis of the US food and drug administration adverse event reporting system

Background: Certain drugs can cause intrinsic or extrinsic tooth discoloration, which is not only a clinical issue but also an esthetic problem. However, limited investigations have focused on drug-induced tooth discoloration. The present work aimed to determine the drugs causing tooth discoloration and to estimate their risks of causing tooth discoloration. Methods: An observational, retrospective, and pharmacovigilance analysis was conducted, in which we extracted adverse event (AE) reports involving tooth discoloration by using the data of the US Food and Drug Administration's Adverse Event Reporting System (FAERS) from the first quarter (Q1) of 2004 to the third quarter (Q3) of 2021. Disproportionality analyses were performed to examine risk signals for tooth discoloration and determine the drugs inducing tooth discoloration. Results: Based on predefined inclusion criteria, 1188 AE reports involving 302 suspected drugs were identified. After data mining, 25 drugs generated positive risk signals for tooth discoloration, of which 10 were anti-infectives for systemic use. The top reported drug was tetracycline (n = 106), followed by salmeterol and fluticasone (n = 68), amoxicillin (n = 60), chlorhexidine (n = 54), and nicotine (n = 52). Cetylpyridinium (PRR = 472.2, ROR = 502.5), tetracycline (PRR = 220.4, ROR = 277), stannous fluoride (PRR = 254.3, ROR = 262.8), hydrogen peroxide (PRR = 240.0, ROR = 247.6), and chlorhexidine (PRR = 107.0, ROR = 108.4) showed stronger associations with tooth discoloration than the remaining drugs. Of 625 AE reports involving 25 drugs with positive risk signals, tooth discoloration was mostly reported in patients aged 45-64 (n = 110) and ≤18 (n = 95), and 29.4% (192/652) of the reports recorded serious outcomes. Conclusion: This study revealed that certain drugs are significantly associated with tooth discoloration. Caution should be exercised when using these drugs, especially during pregnancy and early childhood.

Risk of Dental Discoloration and Enamel Dysplasia in Children Exposed to Tetracycline and Its Derivatives

PURPOSE

To examine the risk of dental abnormalities after exposure to tetracycline and its derivatives (TCs) in Korean children.

MATERIALS AND METHODS

Children aged 0-17 years with a claim for prescriptions of TCs between 2002 and 2015 were identified from the Sample Research Database 2.0 of the National Health Insurance Service. Children not exposed to TCs were selected as the control group by matching sex and age (1:4). Cumulative incidence rate and relative risk of dental abnormalities after TCs exposure were investigated.

RESULTS

The 10-year cumulative incidence rate in the 0-12 years group was 3.1% [95% confidence interval (CI), 2.3-3.9]. The 10-year cumulative incidence rates were 7.0%, 1.9%, and 1.6% in the 0-7, 8-12, and 13-17 years age groups (95% CI: 4.7-9.3, 1.2-2.6, and 1.3-1.9, respectively). There was no significant difference in the risk of dental abnormalities according to TC exposure among the age groups of 0-7 years [adjusted hazard ratio (aHR)=1.0], 8-12 years (aHR=1.1), and 13-17 years (aHR=1.2).

CONCLUSION

Short-term exposure to TCs does not appear to increase the risk of dental abnormalities in children aged 0-7 and 0-12 years. Restrictions on the use of TCs in children aged 8-12 years, in some countries, may warrant consideration.