Severe problem of macrolides resistance to common pathogens in China

Risk factors and prescription patterns analysis for macrolide-resistant Mycoplasma pneumoniae pneumonia in children

First-line macrolide therapy is encountering challenges due to the escalating incidence of macrolide-resistant Mycoplasma pneumoniae pneumonia (MRMPP). This study aimed to illustrate prescription patterns among children diagnosed with either macrolide-sensitive Mycoplasma pneumoniae pneumonia (MSMPP) or MRMPP and to further analyze the risk factors associated with MRMPP. This research encompassed 825 children who were diagnosed with Mycoplasma pneumoniae pneumonia (MPP) at a tertiary hospital located in central China in 2023. Notably, the MRMPP group had a longer fever duration compared to the MSMPP group. A combination of doxycycline and piperacillin-tazobactam was the most frequently used treatment for hospitalized MRMPP children, whereas azithromycin was the primary choice for the MSMPP group. More children in the MRMPP group required discharge medications, primarily doxycycline, whereas the MSMPP group primarily received azithromycin. Furthermore, a history of allergy emerged as an increased risk factor for MRMPP, alongside age, fever, pulmonary imaging changes, and co-detections of bacteria or fungi.

Clinically important interactions of macrolides and tetracyclines with dietary interventions-a systematic review with meta-analyses

BACKGROUND

Effective management of drug-food interactions is crucial for enhancing antibiotics' efficacy/safety. Adhering to PRISMA guidelines, we conducted a systematic review to assess the impact of dietary interventions on the bioavailability of 15 macrolides and 10 tetracyclines.

METHODS

We included studies examining the influence of food, beverages, antacids, and mineral supplements on the pharmacokinetic parameters of orally administered macrolides and tetracyclines. We searched Medline (via PubMed), Embase and Cochrane Library databases up to December 2022. Risk of bias was assessed using Cochrane and NIH tools. Quantitative analyses were conducted if two or more comparable food-effect studies were available; otherwise, a qualitative summary was provided.

RESULTS

We included 120 studies from 97 reports. Meta-analyses were conducted for 8 macrolides and 4 tetracyclines, with qualitative synthesis for 10 and 9, respectively. About 64% of the studies were open-label, crossover designs. Our assessment found that 37% of the studies had a high risk of bias, while only 6% had low risk. Food significantly affected 10 of 13 macrolides (77%) and 6 of 7 tetracyclines (86%). High positive effects on bioavailability were seen with extended-release azithromycin and clarithromycin, and erythromycin estolate. High negative impacts were observed with erythromycin propionate and stearate, azithromycin capsules, demeclocycline and omadacycline. Antacids and mineral supplements significantly decreased tetracyclines absorption. Milk and grapefruit juice showed variable impacts on absorption.

DISCUSSION

Interactions depend on antibiotics' physicochemical characteristics, intervention type, drug formulation and potential patient factors. The quality of evidence was rated low due to outdated studies, methodological diversity and unequal data availability.

Macrolide resistance is pervasive in oral streptococci in the Belgian general population: a cross-sectional survey

Background. Commensal streptococci are common inhabitants of the oral microbiome and regulate its structure and function in beneficial ways for human health. They can, however, also be opportunistic pathogens and act as a reservoir of resistance genes that can be passed on to other bacteria, including pathogens. Little is known about the prevalence of these commensals in parents and their children and their antimicrobial susceptibilities in the Belgian general population.Gap Statement. The macrolide susceptibility of commensal oral Streptococci in Belgium is unknown.Methods. We assessed the prevalence and azithromycin susceptibility of commensal streptococcal species in the parents (n=38) and children (n=50) of 35 families in Belgium.Results. The most frequently detected taxonomic grouping was Streptococcus mitis/oralis, which was detected in 78/181 (43.1%) of the children's isolates and 66/128 (51.6%) of the parents' isolates. Of the 311 isolates collected in this study, 282 isolates (90.7%) had an azithromycin MIC value greater than the breakpoint of 0.25 mg l-1 and 146 isolates (46.9%) had azithromycin MICs greater than 2 mg l-1. There was no difference in the azithromycin MIC distribution of all streptococcal isolates between children and parents. All individuals were colonized by streptococci with azithromycin MICs greater than 0.25 mg l-1, and 87.5% of individuals had streptococci with MICs greater than 2 mg l-1.Interpretation. The most prevalent species identified in both age groups was S. mitis/oralis. All individuals harboured streptococci with macrolide resistance. This highlights the need for additional antimicrobial stewardship initiatives to reduce the consumption of macrolides in the general population.

Novel Efficient Selenium-Based D-π-A NIR Polymer Dots Anodic Electrochemiluminescence Emitter and Its Application in Simultaneous Detection of Two Pneumonia Pathogens with CdS Quantum Dots

Community-acquired pneumonia (CAP) is a major cause of death in children under 5 years old globally. With Streptococcus pneumoniae (S. pneumoniae) and Mycoplasma pneumoniae (M. pneumoniae) being the main pathogens linked to CAP that requires hospitalization, there is an urgent need for a straightforward, cost-efficient, and highly accurate diagnostic method for immediate and early detection of CAP. In this work, benzo[1,2-c;4,5-c']bis([1,2,5]thiadiazole) (BBT) as π-bridge spacer with the donor unit of poly(9,9-dioctylfluorene) (PF) and the acceptor unit of dithienylbenzoselenadiazole (DBS) has been successfully copolymerized to unprecedentedly prepare novel D-π-A selenium-based polymer dots with efficient NIR electrochemiluminescence (named as Se-Pdots in this work). Se-Pdots exclusively generated excellent anodic ECL in the two-component coreaction system comprising TPrA and K2S2O8. Moreover, a potential-resolved ECL biosensor to simultaneously detect S. pneumoniae and M. pneumoniae has also been successfully constructed based on this novel Se-based NIR Pdots as an anodic emitter with CdS QDs as a cathodic emitter. Under optimal conditions, the biosensor has a wide linear range for S. pneumoniae (10-15 to 10-9 M) and M. pneumoniae (10-15 to 10-9 M), with low detection limits for S. pneumoniae (0.56 fM) and M. pneumoniae (0.96 fM). The proposed ECL biosensor provides a simple, sensitive, and reliable method for the simultaneous detection of CAP pathogens in clinical applications.

Applications of β-defensins against infectious pathogenic microorganisms

INTRODUCTION

Antimicrobial peptides (AMPs) are polypeptides with potent antimicrobial activity against a broad range of pathogenic microorganisms. Unlike conventional antibiotics, AMPs have rapid bactericidal activity, a low capacity for inducing resistance, and compatibility with the host immune system. A large body of data supports the antimicrobial activities of a large body of data supports the antimicrobial activities of the class of AMPs known as β-defensins. This review provides a comprehensive analysis of the effects of β-defensins against various pathogenic microorganism: bacteria, fungi, viruses, Mycoplasmas and Chlamydiae. The primary mechanisms of β-defensins against pathogenic microorganisms include inhibition of biofilms formations, dissolution of membranes, disruption of cell walls, and inhibition of adhesion and receptor binding. Although further study and structural modifications are needed, β-defensins are promising candidates for antimicrobial therapy.

AREAS COVERED

This review describes the inhibitory effects of β-defensins on various pathogenic microorganisms. Additionally, we focus on elucidating the mechanisms underlying their actions to provide, providing valuable references for the further study of β-defensins.

EXPERT OPINION

The biological activities and modes of action of β-defensins provide powerful resources for clinical microbial infection management. Addressing the salt sensitivity and toxicity of β-defensins may further enhance their potential applications.

Contaminants of Emerging Concern: Antibiotics Research in Mussels from the Coasts of the Tyrrhenian Sea (Sardinia, Italy)

Contaminants of emerging concern (CECs) are compounds found in several environmental compartments whose ubiquitous presence can cause toxicity for the entire ecosystem. Several personal care products, including antibiotics, have entered this group of compounds, constituting a major global threat. It is essential to develop simple and reliable methods by which to quantify these contaminants in several matrices. In this work, mussels were chosen as sentinel organisms to assess environmental pollution and the safety of bivalve mollusk consumption according to the "One Health perspective". A liquid chromatographic tandem mass spectrometry method (LC-MS/MS) was developed for the quantification of two macrolides, erythromycin (ERY) and azithromycin (AZI), in mussels. This new method was validated according to international guidelines, showing high selectivity, good recoveries (>60% for both of them), sensitivity, and precision. The method was successfully applied for ERY and AZI research in mussels farmed along the Sardinian coasts (Italy), demonstrating itself to be useful for routine analysis by competent authorities. The tested macrolides were not determined in the analyzed sites at concentrations above the limits of detection (LODs). These results demonstrate the food safety of mussels (as concerns the studied antibiotics) and a negligible amount of pollution derived from these drugs in the studied area.

Post-COVID-19 Pandemic Rebound of Macrolide-Resistant Mycoplasma pneumoniae Infection: A Descriptive Study

The rebound characteristics of respiratory infections after lifting pandemic control measures were uncertain. From January to November 2023, patients presenting at a teaching hospital were tested for common respiratory viruses and Mycoplasma pneumoniae using a combination of antigen, nucleic acid amplification, and targeted next-generation sequencing (tNGS) tests. The number and rate of positive tests per month, clinical and microbiological characteristics were analyzed. A rapid rebound of SARS-CoV-2 was followed by a slower rebound of M. pneumoniae, with an interval of 5 months between their peaks. The hospitalization rate was higher, with infections caused by respiratory viruses compared to M. pneumoniae. Though the pediatric hospitalization rate of respiratory viruses (66.1%) was higher than that of M. pneumoniae (34.0%), the 4094 cases of M. pneumoniae within 6 months posed a huge burden on healthcare services. Multivariate analysis revealed that M. pneumoniae-infected adults had more fatigue, comorbidities, and higher serum C-reactive protein, whereas children had a higher incidence of other respiratory pathogens detected by tNGS or pathogen-specific PCR, fever, and were more likely to be female. A total of 85% of M. pneumoniae-positive specimens had mutations detected at the 23rRNA gene, with 99.7% showing A2063G mutation. Days to defervescence were longer in those not treated by effective antibiotics and those requiring a change in antibiotic treatment. A delayed but significant rebound of M. pneumoniae was observed after the complete relaxation of pandemic control measures. No unusual, unexplained, or unresponsive cases of respiratory infections which warrant further investigation were identified.

Correlation between microbial characteristics and reproductive status of the yak uterus based on macrogenomic analysis

INTRODUCTION

This study aimed to investigate the microbial characteristics of yak uteri collected using intrauterine cotton swabs (CS) during different reproductive stages and the correlation of these microbial characteristics with reproductive status.

METHODS

We used a macrogenomic approach to analyze the functional aspects of different microorganisms in samples collected during the pre-estrus, estrus, late estrus, and diestrus stages.

RESULTS

The results revealed the presence of 1293 microbial genera and 3401 microbial species in the uteri of yaks at different reproductive stages. The dominant bacterial species varied across the different periods, with Micrococcus and Proteus being dominant during pre-estrus; Pseudomonas, Clostridium, Flavobacterium, Bacillus, and Staphylococcus during estrus; Acinetobacter, Bacillus and Proteus during late estrus; and Pseudomonas, Escherichia coli, and Proteus during diestrus.

DISCUSSION

The primary functions of these bacteria are enriched in various metabolic pathways, including carbohydrate and amino acid metabolism, intracellular transport and secretion, post-translational protein modification, and drug resistance. These findings suggest that the microbial diversity in the uterus of yaks plays a crucial role in reproductive regulation and can help prevent reproductive tract-related diseases.

Ciprofloxacin enhances the biofilm formation of Staphylococcus aureus via an agrC-dependent mechanism

Staphylococcus aureus readily forms biofilms on host tissues and medical devices, enabling its persistence in chronic infections and resistance to antibiotic therapy. The accessory gene regulator (Agr) quorum sensing system plays a key role in regulating S. aureus biofilm formation. This study reveals the widely used fluoroquinolone antibiotic, ciprofloxacin, strongly stimulates biofilm formation in methicillin-resistant S. aureus, methicillin-sensitive S. aureus, and clinical isolates with diverse genetic backgrounds. Crystal violet staining indicated that ciprofloxacin induced a remarkable 12.46- to 15.19-fold increase in biofilm biomass. Confocal laser scanning microscopy revealed that ciprofloxacin induced denser biofilms. Phenotypic assays suggest that ciprofloxacin may enhance polysaccharide intercellular adhesin production, inhibit autolysis, and reduce proteolysis during the biofilm development, thus promoting initial adhesion and enhancing biofilm stability. Mechanistically, ciprofloxacin significantly alters the expression of various biofilm-related genes (icaA, icaD, fnbA, fnbB, eap, emp) and regulators (agrA, saeR). Gene knockout experiments revealed that deletion of agrC, rather than saeRS, abolishes the ciprofloxacin-induced enhancement of biofilm formation, underscoring the key role of agrC. Thermal shift assays showed ciprofloxacin binds purified AgrC protein, thereby inhibiting the Agr system. Molecular docking results further support the potential interaction between ciprofloxacin and AgrC. In summary, subinhibitory concentrations of ciprofloxacin stimulate S. aureus biofilm formation via an agrC-dependent pathway. This inductive effect may facilitate local infection establishment and bacterial persistence, ultimately leading to therapeutic failure.