Beta-lactam Antibiotics Research Articles

A metagenomics-based approach to decipher the resistome and mobilome of two seahorse species, Hippocampus barbouri and Hippocampus comes

ObjectiveThis study aimed to explore the abundance and diversity of antibiotic resistance genes (ARGs) in seahorses (Hippocampus barbouri and Hippocampus comes) and their surrounding environment. MethodsA combination of shotgun metagenomics and bioinformatics was used to investigate the resistome of both seahorse species. ResultsThe analyses demonstrated a higher abundance of ARGs in seahorse-associated microbiomes, particularly in skin and gut samples, compared to those from water and sediment. Interestingly, genes conferring multidrug resistance (e.g., acrB, acrF, cpxA, msbA, and oqxB) were highly prevalent in all samples, especially in skin and gut samples. High levels of genes conferring resistance to fluoroquinolones (e.g., mfd and emrB), β-lactam (e.g., blaCMY-71, blaOXA-55, and penA), aminocoumarin (e.g., mdtB and mdtC), and peptide antibiotics (arnA, pmrE, and rosA) were also observed in skin and gut samples. An enrichment of mobile genetic elements (MGEs) was also observed in the analysed samples, highlighting their potential role in facilitating the acquisition and spread of ARGs. In fact, the abundance of mobilisation (MOB) relaxases (e.g., MOBF, MOBP, MOBT, and MOBV) in gut and skin samples suggests a high potential for conjugation events. ConclusionsThe occurrence of ARGs and MGEs in seahorses and the surrounding environment raises concerns about their transmission to humans, either through direct contact or the consumption of contaminated seafood. To the best of our knowledge, this study represents the first comprehensive analysis of ARGs in seahorse-associated microbiomes, and its results emphasise the need for monitoring and controlling the spread of ARGs in environmental settings.

An engineered prodrug selectively suppresses β-lactam resistant bacteria in a mixed microbial setting.

The rise of β-lactam resistance necessitates new strategies to combat bacterial infections. We purposefully engineered the β-lactam prodrug AcephPT to exploit β-lactamase activity to selectively suppress resistant bacteria producing extended-spectrum-β-lactamases (ESBLs). Selective targeting of resistant bacteria requires avoiding interaction with penicillin-binding proteins, the conventional targets of β-lactam antibiotics, while maintaining recognition by ESBLs to activate AcephPT only in resistant cells. Computational approaches provide a rationale for structural modifications to the prodrug to achieve this biased activity. We show AcephPT selectively suppresses gram-negative ESBL-producing bacteria in clonal populations and in mixed microbial cultures, with effective selectivity for both lab strains and clinical isolates expressing ESBLs. Time-course NMR experiments confirm hydrolytic activation of AcephPT exclusively by ESBL-producing bacteria. In mixed microbial cultures, AcephPT suppresses proliferation of ESBL-producing strains while sustaining growth of β-lactamase-non-producing bacteria, highlighting its potential to combat β-lactam resistance while promoting antimicrobial stewardship.

A pharmacokinetic framework describing antibiotic adsorption to cardiopulmonary bypass devices.

Cardiopulmonary bypass (CPB) can alter pharmacokinetic (PK) parameters and the drug may adsorb to the CPB device, altering exposure. Cefazolin is a beta-lactam antibiotic used for antimicrobial prophylaxis during cardiac surgery supported by CPB. Adsorption of cefazolin could result in therapeutic failure. An exvivo study was undertaken using CPB devices primed and then dosed with cefazolin and samples were obtained over 1 hour of recirculation. Twelve experimental runs were conducted using different CPB device sizes (neonate, infant, child, and adult), device coatings (Xcoating™, Rheoparin®, PH.I.S.I.O), and priming solutions. The time course of saturable binding, using Bmax (binding capacity), Kd (dissociation constant), and T2off (half-time of dissociation), described cefazolin adsorption. Bmax estimates for the device sizes were neonate 40.0 mg (95% CI 24.3, 67.4), infant 48.6 mg (95% CI 5.97, 80.2), child 77.8 mg (95% CI 54.9, 103), and adult 196 mg (95% CI 191, 199). The Xcoating™ Kd estimate was 139 mg/L (95% CI 27.0, 283) and the T2off estimate was 98.4 min (95% CI 66.8, 129). The Rheoparin® and PH.I.S.I.O coatings had similar binding parameters with Kd and T2off estimates of 0.169 mg/L (95% CI 0.01, 1.99) and 4.94 min (95% CI 0.17, 59.4). The Bmax was small (< 10%) relative to a typical total patient dose during cardiac surgery supported by CPB. A dose adjustment for cefazolin based solely on drug adsorption is not required. This framework could be extended to other PK studies involving CPB.

Beta-lactam-associated hypokalemia.

The aim of this narrative review was to discuss the literature on β-lactam antibiotic-associated hypokalemia, a potentially life-threatening electrolyte disorder. The PubMed, Web of Science, Cochrane Library, and Scopus databases were searched for articles published between 1965 and 2023, using the following terms: 'hypokalemia' OR 'potassium loss' OR 'potassium deficiency' AND 'beta-lactams' OR 'penicillin' OR 'penicillin G' OR 'cephalosporins' OR 'ceftazidime' OR 'ceftriaxone' OR 'flucloxacillin' OR 'carbapenems' OR 'meropenem' OR 'imipenem' OR 'cefiderocol' OR 'azlocillin' OR 'ticarcillin'. Additional search terms were 'hypokalemia' AND 'epidemiology' AND 'ICU' OR 'intensive care unit' OR 'ER' OR 'emergency department' OR 'ambulatory' OR 'old' OR 'ageing population', and experimental (animal-based) studies were excluded. A total of eight studies were selected and discussed, in addition to nine case reports and case series. Both older and currently used β-lactam antibiotics (e.g., ticarcillin and flucloxacillin, respectively) have been associated with therapy-related hypokalemia. The incidence of β-lactam antibiotic-associated hypokalemia may be as high as 40%, thus, the issue of β-lactam-associated hypokalemia remains clinically relevant. Although other causes of hypokalemia are likely to be diagnosed more frequently (e.g., due to diuretic therapy or diarrhea), the possibility of β-lactam-induced renal potassium loss should always be considered in individuals with so-called 'unexplained hypokalemia'.

Antibacterial action of penicillin against Mycobacterium avium complex.

β-lactam antibiotics are promising treatments for Mycobacterium avium complex (MAC) lung disease. We hypothesized that benzylpenicillin has efficacy against MAC. Benzylpenicillin lung concentration-time profiles of seven doses in three dosing schedules were administered for 28 days using the hollow fiber system model of intracellular MAC (HFS-MAC). Data were analyzed using the inhibitory sigmoid maximal effect (Emax) model for each sampling day, while two ordinary differential equations (ODEs) were used for the wild-type and penicillin-resistant mutants. Benzylpenicillin killed >2.1 log10 colony-forming unit (CFU)/mL below Day 0, better than azithromycin, ethambutol, and rifabutin. Efficacy was terminated by acquired resistance. Sigmoid Emax parameter estimates significantly differed between sampling days and were a poor fit. However, ODE model parameter estimates vs. exposure were a better fit. The exposure mediating Emax was 84.6% (95% CI 76.91-82.98) of time concentration exceeded the minimum inhibitory concentration (MIC). In Monte Carlo experiments, 24 million international units of benzylpenicillin continuous infusion achieved the target exposure in lungs of >90% of 10,000 subjects until an MIC of 64 mg/L, designated the susceptibility breakpoint. Benzylpenicillin demonstrated a better bactericidal effect against MAC than guideline-recommended drugs before the development of resistance. Its role in combination therapy with other drugs with better efficacy than guideline-recommended drugs should be explored.

Novel Penicillin Derivatives Against Selected Multiple-drug Resistant Bacterial Strains: Design, Synthesis, Structural Analysis, In Silico and In Vitro Studies.

The rising numbers of multiple drug-resistant (MDR) pathogens and the consequent antibacterial therapy failure that resulted in severe medical conditions push to illustrate new molecules with extended activity against the resistant strains. In this manner, chemical derivatization of known antibiotics is proposed to save efforts in drug discovery, and penicillins serve as an ideal in this regard. Seven synthesized 6-aminopenicillanic acid-imine derivatives (2a-g) were structure elucidated using FT-IR, 1H NMR, 13C NMR, and MS spectroscopy. In silico molecular docking and ADMET studies were made. The analyzed compounds obeyed Lipinski's rule of five and showed promising in vitro bactericidal potential when assayed against E. coli, E. cloacae, P. aeruginosa, S. aureus, and A. baumannii. MDR strains using disc diffusion and microplate dilution techniques. The MIC values were 8 to 32 μg/mL with more potency than ampicillin, explained by better membrane penetration and more ligand-protein binding capacity. The 2g entity was active against E. coli. This study was designed to find new active penicillin derivatives against MDR pathogens. The products showed antibacterial activity against selected MDR species and good PHK, PHD properties, and low predicted toxicity, offering them as future candidates that require further preclinical assays.

Comparing Graph Sample and Aggregation (SAGE) and Graph Attention Networks in the Prediction of Drug-Gene Associations of Extended-Spectrum Beta-Lactamases in Periodontal Infections and Resistance.

Gram-negative bacteria exhibit more antibiotic resistance than gram-positive bacteria due to their cell wall structure and composition differences. Porins, or protein channels in these bacteria, can allow small, hydrophilic antibiotics to diffuse, affecting their susceptibility. Mutations in porin protein genes can also impair antibiotic entry. Predicting drug-gene associations of extended-spectrum beta-lactamases (ESBLs) is crucial as they confer resistance to beta-lactam antibiotics, challenging the treatment of infections. This aids clinicians in selecting suitable treatments, optimizing drug usage, enhancing patient outcomes, and controlling antibiotic resistance in healthcare settings. Graph-based neural networks can predict drug-gene associations in periodontal infections and resistance. The aim of the study was to predict drug-gene associations of ESBLs in periodontal infections and resistance. The study focuses on analyzing drug-gene associations using probes and drugs. The data was converted into graph language, assigning nodes and edges for drugs and genes. Graph neural networks (GNNs) and similar algorithms were implemented using Google Colab and Python. Cytoscape and CytoHubba are open-source software platforms used for network analysis and visualization. GNNswere used for tasks like node classification, link prediction, and graph-level prediction. Three graph-based models were used: graph convolutional network (GCN), Graph SAGE, and graph attention network (GAT). Each model was trained for 200 epochs using the Adam optimizer with a learning rate of 0.01 and a weight decay of 5e-4. The drug-gene association network has 57 nodes, 79 edges, and a 2.730 characteristic path length. Its structure, organization, and connectivity are analyzed using the GCN and Graph SAGE, which show high accuracy, precision, recall, and an F1-score of 0.94. GAT's performance metrics are lower, with an accuracy of 0.68, precision of 0.47, recall of 0.68, and F1-score of 0.56, suggesting that it may not be as effective in capturing drug-gene relationships. Compared to ESBLs, both GCN and Graph SAGE demonstrate excellent performance with accuracy, precision, recall, and an F1-score of 0.94. These results indicate that GCN and Graph SAGE are highly effective in predicting drug-gene associations related to ESBLs. GCN and Graph SAGE outperform GAT in predicting drug-gene associations for ESBLs. Improvements include data augmentation, regularization, and cross-validation. Ethical considerations, fairness, and open-source implementations are crucial for future research in precision periodontal treatment.

Characterization and transmission of plasmid-mediated multidrug resistance in foodborne Vibrio parahaemolyticus.

The purpose of this study was to determine the structural features and transferability of the multidrug-resistance (MDR) plasmid, and resistance phenotypes for the tested antimicrobials in foodborne Vibrio parahaemolyticus. Plasmids were isolated from a V. parahaemolyticus strain of seafood origin, then sequenced using the Illumina NovaSeq 6000 and PacBio Sequel II sequencing platforms to obtain the complete genome data. Characterization of the MDR plasmid pVP52-1, including determination of antimicrobial resistance genes (ARGs), plasmid incompatibility groups, and transferability, was carried out. V. parahaemolyticus strain NJIFDCVp52 contained two circular chromosomes and two circular plasmids (pVP52-1 and pVP52-2). Plasmid typing indicated that pVP52-1 belonged to the incompatibility group IncA/C2 and the sequence type pST3. pVP52-1 carried 12 different ARGs, an IS110-composite transposon consisting of aac(6')-Ib-cr, qnrVC1, aac(6')-Ib, dfrA14, and the IS26-mphA-IS6100 unit flanked by inverted sequences of IS5075 and IS4321. pVP52-2 carried no ARGs. A plasmid elimination assay showed that only pVP52-1 and its ARGs were lost, the loss of resistance to several antimicrobials, causing a change from the ampicillin-ampicillin/sulbactam-cefazolin-cefoxitin-ceftazidime-cefotaxime-imipenem-trimethoprim/sulfamethoxazole resistance pattern to the ampicillin resistance pattern. In accordance, a conjugation transfer assay showed that only pVP52-1 and its ARGs were horizontally transferred, leading to increased antimicrobial resistance in Escherichia coli strain EC600, causing a change from the ampicillin-nalidixic acid resistance pattern to the ampicillin-ampicillin/sulbactam-cefazolin-cefoxitin-ceftazidime-cefotaxime-imipenem-nalidixic acid-chloramphenicol-tetracycline-trimethoprim/sulfamethoxazole-azithromycin resistance pattern. Further transferability experiments revealed that pVP52-1 could be transferred to other enterobacterial strains of E. coli and Salmonella. This study emphasizes the urgent need for continued surveillance of resistance plasmids and changes in antimicrobial resistance profiles among the V. parahaemolyticus population.

Prevalence of Extended-Spectrum ß-Lactamases (ESBLs) and AmpC ß-Lactamases in Clinical Isolates of Multiple Drug-Resistant Escherichia coli

The current study aims to investigate the prevalence of extended-spectrum ß-lactamases (ESBLs) and AmpC β-lactamases in multiple-drug-resistant Escherichia coli (e.g., multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR)) collected from hospitalized patients in Baghdad. The results showed that the prevalence of ESBLs among E.coli isolates was high. From the total 113 E.coli isolates, 75 (66.37%) were ESBL-producing, while 38 (33.63%) were non-ESBL-producing. Out of 75 ESBL-positive isolates, 39 (52%) were obtained from females and 36 (48%) from males. Additionally, 43 (57.33%) isolates were collected from urine samples, and the highest production of ESBLs was obtained from the age group 41–60 years (29.33%). Moreover, out of 111 MDR E.coli, 64 (57.66%) exhibited a positive ESBL test, while 47 (42.34%) did not. Out of 24 XDR E.coli isolates, 11 (45.83%) demonstrated positive ESBLs, while 13 (54.17%) showed negative ESBLs. The antimicrobial susceptibility test results showed that positive ESBL E.coli isolates were more drug-resistant than negative ESBL isolates. The positive ESBLs of E.coli exhibited a higher resistance rate to the β-lactam antibiotics and showed a co-resistance to non-β-lactam antibiotics. Phenotypic detection of AmpC β-lactamase by the screening of cefoxitin-resistant isolates revealed that 43 (38.05%) isolates were considered positive for AmpC β-lactamase production. However, the PCR technique gives different results. In conclusion, the prevalence of ESBL and AmpC β-lactamase producing E. coli is rapidly increasing among clinical isolates of MDR, XDR, and possibly PDR E.coli.

Synergistic Interactions between Selected β-Lactam Antibiotics and Cinnamic Acid and Its Chosen Derivatives.

Staphylococcus epidermidis, a component of human microbiota, may also cause life-threatening opportunistic infections. These are becoming increasingly common infections associated with the implantation of various implants. Due to the exhaustion of antibiotic resources, new substances with antimicrobial activity are being sought. The present study examined the antibacterial effect of cinnamic acid and its derivatives and their combinations with β-lactam antibiotics on the growth of Staphylococcus epidermidis strains isolated from vascular infections. The data obtained during the research indicated that cinnamic acid and its derivatives, sinapic acid, ferulic acid, and p-coumaric acid, have weak antibacterial activity (MIC values at the level of 2048 and 4096 mg/L). The combination of cinnamic acid and its derivatives with β-lactam antibiotics increases the effectiveness of their action and may demonstrate various pharmacological effects depending on the established cutoff.

Highly Specific Voltammetric Detection of Cephalexin in Tablet Formulations and Human Urine Samples Using a Poly(2,4,6-2',4',6'-hexanitrodiphenylamine)-Modified Glassy Carbon Electrode.

β-Lactam antibiotics are employed to treat bacterial illnesses. Despite a high level of clinical success, they have encountered serious resistance that demands a high-dose regimen and a new pharmacokinetic combination. This requires continuous monitoring of their levels in pharmaceutical and biological samples. In this study, an electrochemical sensor was developed for the determination of cephalexin (CLN) in pharmaceutical formulations and biological fluid samples. The sensors were developed by modifying a glassy carbon electrode (GCE) using a conducting polymer (dipicrylamine) by potentiodynamic electropolymerization. Characterization (using cyclic voltammetry and electron impedance spectroscopy) results revealed modification of the electrode surface, leading to an enhanced effective electrode surface area and their conductivity. The appearance of an irreversible oxidative peak at much-reduced potential with 5-fold current enhancement at a poly(dipicrylamine)-modified glassy carbon electrode (poly(DPA)/GCE) verified the electrocatalytic role toward CLN. Under optimized conditions, a wider linear concentration range (5 × 10-8 to 3.0 × 10-4 M), lowest limit of detection (LoD) (2.5 nM), detected amount of each tablet brand above 97.00% of the labeled value (showing excellent agreement between the detected amount and company label), and excellent % recovery results in pharmaceutical and biological samples were obtained with an excellent interference recovery error of less than 4.05%. Its excellent accuracy, selectivity, reproducibility, and stabilities and only requiring a simple electrode modification step combined with its readily available and nontoxic modifier, which sets it apart from most previously reported methods, have validated the present method's potential applicability for determining CLN in biological and pharmaceutical samples.

Les infections urinaires chez les insuffisants rénaux chroniques hospitalisés en Néphrologie, Centre Hospitalier Universitaire Befelatanana, Antananarivo

Urinary tract infection is the leading cause of nosocomial infection worldwide. It is a factor in the progression of chronic kidney disease. To determine the epidemiological, clinical, microbiological, therapeutic and evolving profile of patients with chronic kidney disease and urinary tract infection. This was a retrospective, descriptive study lasting 5 years, from January 2014 to december 2018 in chronic kidney disease with urinary tract infection. Fifty-one patients (7.15%) were retained with a mean age of 53.03 years and a sex ratio of 0.55. Chronic kidney disease was in end-stage in 45.1% (n=23). Cystitis was found in 49.02% (n=25) and gram-negative bacilli were found in 74.50% (n=38), predominantly Escherichia coli (54.90%). Third generation of cephalosporins and fluoroquinolones were frequently prescribed as probabilistic antibiotics. Resistance to beta-lactam antibiotics was 50% for Escherichia coli. Factors influencing severe infection were: advanced age, male gender, urinary lithiasis, multiple antibiotic resistance and non-enterobacterial germs. Urinary tract infection in chronic kidney disease were frequent and particularly severe.

Epidemiological Characteristics and Drug Resistance Analysis of 187 Strains of Carbapenem-Resistant Enterobacteriaceae in a General Hospital

Background: Carbapenem antibiotics are currently the most broad-spectrum and potent β-lactam antibiotics. Without effective intervention measures, Carbapenem-Resistant Enterobacteriaceae (CRE) may become widespread in all healthcare institutions within ten years, potentially developing into an endemic issue. Objectives: To understand the epidemiological characteristics and multilocus sequence typing (MLST) of CRE infections in hospitals, and to explore critical strategies for preventing and controlling CRE hospital infections. Methods: The study focused on hospitalized patients with CRE strains isolated by the Laboratory Department of the First Affiliated Hospital of Guizhou University of Traditional Chinese Medicine from 2020 to 2022. Patient data, bacterial isolation, culture, and drug sensitivity results were collected and analyzed to determine the epidemiological characteristics of CRE infections. Preserved Carbapenem-Resistant Klebsiella pneumoniae (CRKP) strains were reviewed, and the CRKP sequence type (ST) was obtained through MLST typing. Results: Over the past three years, 187 CRE strains were isolated in the hospital, with infections predominantly occurring in males and individuals over 60 years old. The departments with the highest detection rates were the ICU (35.29%), geriatric department (11.23%), and rehabilitation department (8.02%). The top three specimen sources were sputum (43.85%), clean midstream urine (32.09%), and secretions (13.90%). carbapenem-resistant Klebsiella pneumoniae accounted for the majority of CRE isolates (80.21%), followed by carbapenem-resistant Escherichia coli (14.44%). Carbapenem-resistant Enterobacteriaceae strains exhibited a high resistance rate to most commonly used antibiotics but were sensitive to tigecycline. Multilocus sequence typing results from 11 CRKP strains showed that 90.91% were of the ST11 type, while 9.09% were of the ST15 type. Conclusions: From 2020 to 2022, CRE infections at the hospital primarily affected elderly male patients over 60, with CRKP as the predominant pathogen and ST11 as the main sequence type. Carbapenem-resistant Enterobacteriaceae strains were highly resistant to most commonly used antimicrobial drugs. Hospitals should prioritize the prevention and control of CRE infections, emphasizing the management of antimicrobial drugs, patient identification, environmental hygiene, and infection control measures to prevent outbreaks caused by CRE.

Restoring susceptibility to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus.

Infections by Staphylococcus aureus have been treated historically with β-lactam antibiotics. However, these antibiotics have become obsolete in methicillin-resistant S. aureus by acquisition of the bla and mec operons. The presence of the β-lactam antibiotic is detected by the sensor domains of BlaR and/or MecR, and the information is transmitted to the cytoplasm, resulting in derepression of the antibiotic-resistance genes. We hypothesized that inhibition of the sensor domain would shut down this response system, and β-lactam susceptibility would be restored. An in silico search of 11 million compounds led to a benzimidazole-based hit and, ultimately, to the boronate 4. The X-ray structure of 4 is covalently engaged with the active-site serine of BlaR. Compound 4 potentiates by 16- to 4,096-fold the activities of oxacillin and of meropenem against methicillin-resistant S. aureus strains. The combination of 4 with oxacillin or meropenem shows efficacy in infected mice, validating the strategy.

Biofilm Formation and Antibiotic Resistance Profiles in Carbapenemase-Producing Gram-Negative Rods-A Comparative Analysis between Screening and Pathological Isolates.

(1) Background: Carbapenem-resistant (CR) bacteria pose a significant global public health challenge due to their ability to evade treatment with beta-lactam antibiotics, including carbapenems. This study investigates the biofilm-forming capabilities of CR clinical bacterial isolates and examines the impact of serum on biofilm formation. Additionally, the study evaluates the resistance profiles and genetic markers for carbapenemase production. (2) Methods: Bacterial isolates were collected from the microbiology laboratory of Mures County Clinical Hospital between October 2022 and September 2023. Pharyngeal and rectal swabs were screened for carbapenem-resistant bacteria using selective media. Lower respiratory tract samples were also analyzed for CR Gram-negative bacteria. The isolates were tested for their ability to form biofilms in the presence and absence of fetal bovine serum at 24 and 48 h. Carbapenemase production was detected phenotypically and confirmed via PCR for relevant genes. (3) Results: Out of 846 screened samples, 4.25% from pharyngeal swabs and 6.38% from rectal swabs tested positive for CR bacteria. Acinetobacter baumannii and Klebsiella pneumoniae were the most common species isolated. Biofilm formation varied significantly between clinical isolates and standard strains, with clinical isolates generally showing higher biofilm production. The presence of serum had no significant effect on biofilm formation in Klebsiella spp., but stimulated biofilm formation for Acinetobacter spp. Carbapenemase genes blaKPC, blaOXA-48-like, and blaNDM were detected in various isolates, predominantly in Klebsiella spp., but were not the main determinants of carbapenem resistance, at least in screening isolates. (4) Conclusions: This study highlights the variability in biofilm formation among CR clinical isolates and underscores the differences between the bacteria found as carriage versus infection. Both bacterial species and environmental factors variably influence biofilm formation. These insights are crucial for the development of effective treatment and infection control strategies in clinical settings.

Evaluation of synergism effect of human glucose-dependent insulinotropic polypeptide (GIP) on Klebsiella pneumoniae carbapenemases (KPC) producer isolated from clinical samples

Antibiotic resistance is increasing among Gram-negative bacteria, prompting the development of new antibiotics as well as alternative treatment approaches. Klebsiella pneumoniae Carbapenemases (KPC) has become a major concern in the treatment of infections, since KPC-producing bacteria are resistant to a number of β -lactam and non β-lactam antibiotics in addition to hydrolyzing carbapenemases. The aim of this study is to examine the synergistic effect of human Glucose-dependent Insulinotropic Polypeptide (GIP) on KPC producer. The K. pneumoniae isolates were identified by using biochemical tests and PCR genotyping. The disc diffusion method was used to assess the antimicrobial susceptibility of each isolate, and the modified Hodge test (MHT) was used to find carbapenemases. Agar well diffusion and minimum inhibitory concentration (MIC) assays were used to validate the synergistic effect of GIP against Klebsiella species. MIC values of chosen antimicrobial compounds demonstrated a considerable synergism impact when combined with human GIP, particularly against KPC strains. The antibacterial activity of the antimicrobial compounds was boosted by 4–16 times due to human GIP, reducing the MIC values. The fractional inhibitory concentration (FIC) ranged from 0.032 to 0.25 for examined antibiotics. Thus, GIP can be considered an antibacterial adjuvant with the potential to supplement the current antibiotic spectrum.

Activity of Synthetic Peptide KP and Its Derivatives against Biofilm-Producing Escherichia coli Strains Resistant to Cephalosporins.

Bacterial resistance to β-lactam antibiotics, particularly new generation cephalosporins, is a major public health concern. In Escherichia coli, resistance to these antibiotics is mainly mediated by extended-spectrum β-lactamases (ESBL), which complicates a range of health-threatening infections. These infections may also be biofilm-related, making them more difficult to treat because of the higher tolerance to conventional antibiotics and the host immune response. In this study, we tested as potential new drug candidates against biofilm-forming ESBL-producing E. coli four antimicrobial peptides previously shown to have antifungal properties. The peptides proved to be active in vitro at micromolar concentrations against both sensitive and ESBL-producing E. coli strains, effectively killing planktonic cells and inhibiting biofilm formation. Quantitative fluorescence intensity analysis of three-dimensional reconstructed confocal laser scanning microscopy (CLSM) images of mature biofilm treated with the most active peptide showed significant eradication and a reduction in viable bacteria, while scanning electron microscopy (SEM) revealed gross morphological alterations in treated bacteria. The screening of the investigated peptides for antibacterial and antibiofilm activity led to the selection of a leading candidate to be further studied for developing new antimicrobial drugs as an alternative treatment against microbial infections, primarily associated with biofilms.

Click chemistry-based fluorescence polarization sensor for sensitive detection of ampicillin

Ampicillin (AMP) is a β-lactam antibiotic that can inhibit bacterial wall synthesis. The overuse and misuse of AMP makes it micropollutant that commonly found in food and various environmental media. In this work, a fluorescence polarization sensor was designed to sensitive detection of trace ampicillin based on click chemistry, using graphene oxide (GO) as a fluorescence polarization (FP) signal enhancement element. First, when ampicillin binds to its aptamer (apt), the adjacent alkyne and azide groups are separated, hindering the click-linking reaction. When Carboxyfluorescein (FAM) fluorophore-labeled probe (C-FAM) is added, its protruding 3-terminal FAM is recognized and cleaved by exonuclease I (EXO I), releasing fluorophores free that could not be adsorbed on GO, resulting in a lo0wer polarization signal. If there is no AMP in the system, aptamer probe is connected to its complementary chain ends by a click reaction. After C-FAM hybridizes with apt, the apt/P duplex is opened and the prominent single-stranded ends adsorb on the GO, leading a significantly enhanced FP signal. According to the relationship between the difference in FP values and the concentrations of AMP, the limit of detection of proposed method is as low as 80 pg/mL. This assay has a wide linear range plus excellent selectivity, and has been applied to detect AMP in milk and river water samples with satisfactory results, which demonstrates that the FP sensor has great potential for practical applications in food safety and environmental protection fields.

The study of honokiol as a natural product-based antimicrobial agent and its potential interaction with FtsZ protein.

Multidrug resistant bacteria have been a global health threat currently and frontline clinical treatments for these infections are very limited. To develop potent antibacterial agents with new bactericidal mechanisms is thus needed urgently to address this critical antibiotic resistance challenge. Natural products are a treasure of small molecules with high bioactive and low toxicity. In the present study, we demonstrated that a natural compound, honokiol, showed potent antibacterial activity against a number of Gram-positive bacteria including MRSA and VRE. Moreover, honokiol in combination with clinically used β-lactam antibiotics exhibits strong synergistic antimicrobial effects against drug-resistant S. aureus strains. Biochemical studies further reveal that honokiol may disrupt the GTPase activity, FtsZ polymerization, cell division. These biological impacts induced by honokiol may ultimately cause bacterial cell death. The in vivo antibacterial activity of honokiol against S. aureus infection was also verified with a biological model of G. mellonella larvae. The in vivo results support that honokiol is low toxic against the larvae and effectively increases the survival rate of the larvae infected with S. aureus. These findings demonstrate the potential of honokiol for further structural advancement as a new class of antibacterial agents with high potency against multidrug-resistant bacteria.

Ceftriaxone and MC-100093 mitigate fentanyl-induced cardiac injury in mice: Preclinical investigation of its underlying molecular mechanisms

Drug addiction is considered a worldwide concern and one of the most prevailing causes of death globally. Opioids are highly addictive drugs, and one of the most common opioids that is frequently used clinically is fentanyl. The potential harmful effects of chronic exposure to opioids on the heart are still to be elucidated. Although β-lactam antibiotics are well recognized for their ability to fight bacteria, its protective effect in the brain and liver has been reported. In this study, we hypothesize that β-lactam antibiotic, ceftriaxone, and the novel synthetic non-antibiotic β-lactam, MC-100093, are cardioprotective against fentanyl induced-cardiac injury by upregulating xCT expression. Mice were exposed to repeated low dose (0.05 mg/kg, i.p.) of fentanyl for one week and then challenged on day 9 with higher dose of fentanyl (1 mg/kg, i.p.). This study investigated cardiac histopathology and target genes and proteins in serum and cardiac tissues in mice exposed to fentanyl overdose and β-lactams. We revealed that fentanyl treatment induced cardiac damage as evidenced by elevated cardiac enzymes (troponin I). Furthermore, fentanyl treatment caused large aggregations of inflammatory cells and elevation in the areas and volumes of myocardial fibers, indicating hypertrophy and severe cardiac damage. Ceftriaxone and MC-100093 treatment, However, induced cardioprotective effects as evidenced by marked reduction in cardiac enzymes (troponin I) and changes in histopathology. Furthermore, ceftriaxone and MC-100093 treatment decreased the levels of hypertrophic genes (α-MHC & β-MHC), apoptotic (caspase-3), and inflammatory markers (IL-6 & NF-κB). This study reports for the first time the cardioprotective effect of β-lactams against fentanyl-induced cardiac injury. Further studies are greatly encouraged to completely identify the cardioprotective properties of ceftriaxone and MC-100093.