Development Of Antibiotic Resistance Research Articles

Adaptive evolution of extensive drug resistance and persistence in epidemic ST11 KPC-producing Klebsiella pneumoniae during antimicrobial chemotherapy.

The global rise of carbapenem-resistant Klebsiella pneumoniae, including strains producing K. pneumoniae carbapenemase (KPC) types, poses a significant public health challenge due to their resistance to critical antibiotics. Treatment options for infections caused by KPC-producing K. pneumoniae (KPC-KP) are increasingly limited, particularly as these strains develop resistance to last-line antibiotics such as ceftazidime/avibactam and colistin. This study investigates the evolution of antibiotic resistance and persistence in a series of clonally related ST11 KPC-KP strains isolated from a single patient undergoing extended antimicrobial treatment. The patient, a 47-year-old male with a history of kidney transplantation, developed multiple KPC-KP lung infections during his hospital stay. Resistance to colistin and ceftazidime/avibactam emerged during treatment with these antibiotics. Key resistance mechanisms identified included the integration of ISKpn26 into mgrB gene, leading to mgrB inactivation and colistin resistance, and the emergence of novel blaKPC-2 variants (blaKPC-71 and blaKPC-179) that confer resistance to ceftazidime/avibactam. Despite the development of colistin resistance in a ceftazidime/avibactam-resistant KPC-KP strain following combination therapy, the patient's clinical condition significantly improved. Phenotypic assays showed that mgrB disruption in KPC-KP resulted in increased biofilm formation and higher susceptibility to phagocytosis. In mouse models, KPC-KP strains with mgrB disruption showed reduced virulence, increased lung colonization and persistence, and a lower inflammatory response, suggesting that mgrB disruption facilitates the transition from acute infection to colonization. This study highlights the complex interplay between antibiotic resistance and bacterial fitness, offering insights into why some patients experience clinical improvement despite severe drug resistance and incomplete bacterial clearance.

The impact of zinc pre-exposure on ciprofloxacin resistance development in E. coli

IntroductionAntimicrobial resistance (AMR) is a global health crisis that is predicted to worsen in the coming years. While improper antibiotic usage is an established driver, less is known about the impact of other endogenous and exogeneous environmental factors, such as metals, on AMR. One metal of interest is zinc as it is often used as a supplement for diarrhea treatment prior to antibiotics.Materials and methodsHere, we probed the impact of zinc on ciprofloxacin resistance in E. coli via altering zinc exposure time and order. We found that the order of exposure to zinc impacted resistance development. These impacted samples then underwent whole genome and RNA sequencing analysis.ResultsZinc pre-exposure led to a subsequent acceleration of ciprofloxacin resistance. Specifically, we saw that 5 days of zinc pre-exposure led samples to have nearly a 4× and 3× higher MIC after 2 and 3 days of subinhibitory antibiotics, respectively, compared to samples not pre-exposed to zinc, but only if ciprofloxacin exposure happened in the absence of zinc. Additionally, for samples that underwent the same pre-exposure treatment, those exposed to a combination of zinc and ciprofloxacin saw delayed ciprofloxacin resistance compared to those exposed to only ciprofloxacin resulting in up to a 5× lower MIC within the first 2 days of antibiotic exposure. We did not observe any genetic changes or changes in antibiotic tolerance in cells after zinc pre-exposure, suggesting changes in gene expression may underlie these phenotypes.DiscussionThese results highlight the need to reexamine the role of zinc, and supplements more broadly, on antibiotic resistance evolution.

Role and mechanism of the outer membrane porin LamB in T-2 mycotoxin-mediated extensive drug resistance in Escherichia coli

The influence of mycotoxins in ecological niches shared with antibiotic-resistant bacteria (ARB) remains underexplored. This study examined the impact of T-2 mycotoxin on the evolution of antibiotic resistance in Escherichia coli, highlighting the role of specific porins. Our findings revealed that exposure to 10ng/mL of T-2 toxin induced multi-drug resistant (MDR) phenotypes in three E. coli. At 10-5ng/mL, T-2 toxin caused E. coli ATCC 25922 to develop stable resistance to 13 critical antibiotics, with minimum inhibitory concentrations (MICs) increasing 16- to several thousand-fold. This resistance was linked to the downregulation of the mal gene cluster. Notably, T-2 toxin reduced membrane permeability by downregulating lamB, facilitating its own entry and reducing the intracellular accumulation of both the toxin and antibiotics, thereby enhancing resistance development. LamB mediated the XDR phenotypes in E. coli, particularly by blocking last-resort antibiotics such as cephalosporins, carbapenems, tigecycline, and colistin, complicating treatment strategies. LamB demonstrated high binding affinities for T-2 toxin and various antibiotics, with specific binding sites identified for meropenem (Arg134), imipenem (Ser148, Arg170, Lys129), ceftazidime (Phe106, Lys129), and cefepime (Tyr66, Gln267, Lys269), exhibiting binding energies of -2.93, -2.58, -2.53, and -4.3, respectively. These findings suggest that even low levels of T-2 mycotoxin pose a substantial public health risk. They underscore the urgent need to address these contaminants and open new avenues for antibiotic resistance research.

Changes in antibiotic resistance patterns of Gram-negative bacilli across three different wastewater treatment plants in northwest Algeria; first comparative study.

Changes in antibiotic resistance of bacteria in three different wastewater treatment plants (WTP) were investigated to determine their role they play in the dissemination of multidrug resistant bacteria (MDR). Water samples were collected from downstream of three (WTP) from where pollution parameters were detected and high-performance Liquid chromatography (HPLC) coupled with an ultraviolet (UV) detector was used to measure antibiotic residues. In addition, 88 bacilli Gram-negative (BGN) were collected; activated sludge, aerated lagoons and natural lagoons, and tested for resistance against 18 βeta-lactam antibiotics. We evaluated the production of Extended-spectrum ß-lactamases (ESBLs) in isolates that were further confirmed by applying the automated VITEK-2 system. Among the 88 isolates, Klebsiella pneumoniae (60%),Escherichia coli (23,33%) and Serratia marcescens(32,14%) were the most isolated species. The abundance of the CTX ESBL-producers strains was significantly higher in natural lagoons that may have a greater influence on the occurrence and prevalence of MDR, with the MAR index being the lowest for Serratia marcescens (0,27) and the highest for Citrobacter koseri (0,88), serving as a hotspot environment for the evolution of Antibiotic resistance. Controlling or avoiding this kind of treatment can reduce the chance of MDRs entrance to the environment.

Antibiotic Resistance in humans due to Microbes

Background Antibiotics are now facing a crisis of resistance. Overuse and misuse have led to bacteria developing resistance, making infections harder to treat. This is exacerbated by the availability of antibiotics without prescriptions and their presence in the environment. The spread of resistant bacteria poses a significant threat to global health, requiring urgent action. Governments and international organizations are working to combat this issue, but the problem persists. Addressing antibiotic resistance requires responsible use and the development of new antibiotics. Objective This study aimed to review antibiotic resistance in humans due to microbes. Discussion Antimicrobial resistance (AMR) is a natural process where microorganisms stop responding to antibiotics, making infections harder to treat and increasing the risk of spreading serious diseases. The overuse of antibiotics accelerates this process, promoting AMR spread through distinct mechanisms like natural and acquired resistance. Genetic mechanisms involve inherent and acquired resistance in bacteria, impacting antibiotic effectiveness. Biological resistance mechanisms include enzymatic inhibition, reduced penetration, enhanced extrusion, and target changes. Strategies against antimicrobial agents involve restricting drug entry, modifying targets, rendering drugs inactive, and actively removing drugs from cells. Gram-negative and gram-positive bacteria exhibit variations in resistance mechanisms due to structural differences. Conclusion The development of antibiotic resistance in bacteria is a multifaceted issue, involving both inherent and acquired mechanisms. Inherent resistance stems from genetic mutations that occur spontaneously within bacterial populations. On the other hand, acquired resistance can occur through the transfer of genetic material between bacteria, enabling the spread of resistance traits. It is imperative to grasp these genetic, biological, and strategic mechanisms to effectively tackle the escalating challenge of antibiotic resistance and devise successful strategies to mitigate its impact.

Targeting histidinol-phosphate aminotransferase in Acinetobacter baumannii with salvianolic acid B: A structure-based approach to novel antibacterial strategies

Undoubtedly, Acinetobacter baumannii is a major ESKAPE pathogen that poses a significant threat to public health, causing severe nosocomial infections with high mortality rates in healthcare settings. Due to the rapid development of antibiotic resistance, only a limited number of antibiotics remain effective against infections caused by multidrug-resistant (MDR) Acinetobacter baumannii. The discovery of new class of antibiotic molecules still lags behind the rate of growing worldwide burden of antimicrobial resistance (AMR). To expedite the discovery of new therapeutic molecules, we have focused on HisC from A. baumannii (AbHisC), a crucial enzyme involved in the seventh step of histidine biosynthesis. This pathway is absent in humans. We have employed the advanced computational techniques to target this promising drug target. AbHisC was cloned, overexpressed, and purified. Three distinct sets of libraries containing ∼60,000 natural compounds from ZINC database were screened against AbHisC using Schrödinger's glide module software. Based on the docking score and glide energy, top 25 hits were further subjected to induced fit (IF) docking. Top four out of the twenty five compounds from IF docking were subjected to 100ns molecular dynamics simulations, and it was observed that salvianolic acid B (SA-B) (a naturally occurring compound) complex with AbHisC, was found to be extremely stable. The glide energy and docking score of SA-B were −88.59 kcal/mol and −10.4 kcal/mol. SA-B was also found to quench the intrinsic fluorescence of tyrosine indicating its binding to the target. The dissociation constant calculated using Surface Plasmon Resonance was found to be 3.4x10−9 M. Based on these results we can conclude that SA-B can serve as the potential inhibitor of AbHisC that can further form the basis of structure based drug design against this deadly pathogen.

Preparation and Characterization of Tiamulin-Loaded Niosomes for Oral Bioavailability Enhancement in Mycoplasma-Infected Broilers

Mycoplasma infections pose significant challenges in the poultry industry, necessitating effective therapeutic interventions. Tiamulin, a veterinary antibiotic, has demonstrated efficacy against Mycoplasma species. However, the emergence of resistant Mycoplasma species could dramatically reduce the therapeutic potential, contributing to economic losses. Optimizing the tiamulin’s pharmacokinetic profile via nanocarrier incorporation could enhance its therapeutic potential and reduce the administration frequency, ultimately reducing the resistant strain emergence. Niosomes, a type of self-assembled non-ionic surfactant-based nanocarrier, have emerged as a promising drug delivery system, offering improved drug stability, sustained release, and enhanced bioavailability. In this study, niosomal nanocarriers encapsulating tiamulin were prepared, characterized and assessed in Mycoplasma-inoculated broilers following oral administration. Differential scanning colorimetry (DSC) confirmed the alterations in the crystalline state following components integration into the self-assembled structures formed during the formulation procedure. Transmission electron microscopy (TEM) showed the spherical nanostructure of the formed niosomes. The formulated nanocarriers exhibited a zeta potential and average hydrodynamic diameter of −10.65 ± 1.37 mV and 339.67 ± 30.88 nm, respectively. Assessment of the pharmacokinetic parameters following oral administration to Mycoplasma gallisepticum-infected broilers revealed the ability of the niosomal nanocarriers to increase the tiamulin’s bioavailability and systemic exposure, marked by significantly higher area under the curve (AUC) (p < 0.01) and prolonged elimination half-life (T1/2) (p < 0.05). Enhanced bioavailability and prolonged residence time are crucial factors in maintaining therapeutic concentrations at reduced doses and administration frequencies. This approach provides a viable strategy to decrease the risk of subtherapeutic levels, thereby mitigating the development of antibiotic resistance. The findings presented herein offer a sustainable approach for the efficient use of antibiotics in veterinary medicine.

Effects of glyphosate on antibiotic resistance in soil bacteria and its potential significance: A review.

The evolution and spread of antibiotic resistance are problems with important consequences for bacterial disease treatment. Antibiotic use in animal production and the subsequent export of antibiotic resistance elements in animal manure to soil is a concern. Recent reports suggest that exposure of pathogenic bacteria to glyphosate increases antibiotic resistance. We review these reports and identify soil processes likely to affect the persistence of glyphosate, antibiotic resistance elements, and their interactions. The herbicide molecular target of glyphosate is not shared by antibiotics, indicating that target-site cross-resistance cannot account for increased antibiotic resistance. The mechanisms of bacterial resistance to glyphosate and antibiotics differ, and bacterial tolerance or resistance to glyphosate does not coincide with increased resistance to antibiotics. Glyphosate in the presence of antibiotics can increase the activity of efflux pumps, which confer tolerance to glyphosate, allowing for an increased frequency of mutation for antibiotic resistance. Such effects are not unique to glyphosate, as other herbicides and chemical pollutants can have the same effect, although glyphosate is used in much larger quantities on agricultural soils than most other chemicals. Most evidence indicates that glyphosate is not mutagenic in bacteria. Some studies suggest that glyphosate enhances genetic exchange of antibiotic-resistance elements through effects on membrane permeability. Glyphosate and antibiotics are often present together in manure-treated soil for at least part of the crop-growing season, and initial studies indicate that glyphosate may increase abundance of antibiotic resistance genes in soil, but longer term investigations under realistic field conditions are needed. Although there are demonstratable interactions among glyphosate, bacteria, and antibiotic resistance, there is limited evidence that normal use of glyphosate poses a substantial risk for increased occurrence of antibiotic-resistant, bacterial pathogens. Longer term field studies using environmentally relevant concentrations of glyphosate and antibiotics are needed.

Membrane lipid homeostasis dually regulates conformational transition of phosphoethanolamine transferase EptA

The phosphoethanolamine transferase EptA utilizes phosphatidylethanolamine (PE) in the bacterial cell membrane to modify the structure of lipopolysaccharide, thereby conferring antimicrobial resistance on Gram-negative pathogens. Previous studies have indicated that excessive consumption of PE can disrupt the cell membrane, leading to cell death. This implies the presence of a regulatory mechanism for EptA catalysis to maintain a balance between antimicrobial resistance and bacterial growth. Through microsecond-scale all-atom molecular dynamics simulations, we demonstrate that membrane lipid homeostasis modulates the conformational transition and catalytic activation of EptA. The conformation of EptA oscillates between closed and open states, ensuring the precise spatiotemporal sequence of substrates binding. Interestingly, the conformation of EptA is significantly influenced by its surrounding lipid microenvironment, particularly the PE proportion in the membrane. PE-rich membrane conditions initiate and stabilize the open conformation of EptA through both orthosteric and allosteric effects. Importantly, the reaction mediated by EptA gradually depletes PE in the membrane, ultimately hindering its conformational transition and catalytic activation. These findings collectively establish a self-promoted model, illustrating the regulatory mechanism of EptA during the development of antibiotic resistance.

Insights into an indolicidin-derived low-toxic anti-microbial peptide's efficacy against bacterial cells while preserving eukaryotic cell viability.

Antimicrobial peptides (AMPs) are a current solution to combat antibiotic resistance, but they have limitations, including their expensive production process and the induction of cytotoxic effects. We have developed novel AMP candidate (peptide 3.1) based on indolicidin, among the shortest naturally occurring AMP. The antimicrobial activity of this peptide is demonstrated by the minimum inhibitory concentration, while the hemolysis tests and MTT assay indicate its low cytotoxicity. In optical diffraction tomography, red blood cells treated with peptide 3.1 showed no discernible effects, in contrast to indolicidin. However, peptide 3.1 did induce cell lysis in E. coli, leading to a reduced potential for the development of antibiotic resistance. To investigate the mechanism underlying membrane selectivity, the structure of peptide 3.1 was analyzed using nuclear magnetic resonance spectroscopy and molecular dynamics simulations. Peptide 3.1 is structured with an increased distinction between hydrophobic and charged residues and remained in close proximity to the eukaryotic membrane. On the other hand, peptide 3.1 exhibited a disordered conformation when approaching the prokaryotic membrane, similar to indolicidin, leading to its penetration into the membrane. Consequently, it appears that the amphipathicity and structural rigidity of peptide 3.1 contribute to its membrane selectivity. In conclusion, this study may lead to the development of Peptide 3.1, a promising commercial candidate based on its low cost to produce and low cytotoxicity. We have also shed light on the mechanism of action of AMP, which exhibits selective toxicity to bacteria while not damaging eukaryotic cells.

Antimicrobial Peptides: The Game-Changer in the Epic Battle Against Multidrug-Resistant Bacteria.

The rapid progress of antibiotic resistance among bacteria has prompted serious medical concerns regarding how to manage multidrug-resistant (MDR) bacterial infections. One emerging strategy to combat antibiotic resistance is the use of antimicrobial peptides (AMPs), which are amino acid chains that act as broad-spectrum antimicrobial molecules and are essential parts of the innate immune system in mammals, fungi, and plants. AMPs have unique antibacterial mechanisms that offer benefits over conventional antibiotics in combating drug-resistant bacterial infections. Currently, scientists have conducted multiple studies on AMPs for combating drug-resistant bacterial infections and found that AMPs are a promising alternative to conventional antibiotics. On the other hand, bacteria can develop several tactics to resist and bypass the effect of AMPs. Therefore, it is like a battle between the bacterial community and the AMPs, but who will win? This review provides thorough insights into the development of antibiotic resistance as well as detailed information about AMPs in terms of their history and classification. Furthermore, it addresses the unique antibacterial mechanisms of action of AMPs, how bacteria resist these mechanisms, and how to ensure AMPs win this battle. Finally, it provides updated information about FDA-approved AMPs and those that were still in clinical trials. This review provides vital information for researchers for the development and therapeutic application of novel AMPs for drug-resistant bacterial infections.

Genetic stability of Mycobacterium smegmatis under the stress of first-line antitubercular agents

The sustained success of Mycobacterium tuberculosis as a pathogen arises from its ability to persist within macrophages for extended periods and its limited responsiveness to antibiotics. Furthermore, the high incidence of resistance to the few available antituberculosis drugs is a significant concern, especially since the driving forces of the emergence of drug resistance are not clear. Drug-resistant strains of Mycobacterium tuberculosis can emerge through de novo mutations, however, mycobacterial mutation rates are low. To unravel the effects of antibiotic pressure on genome stability, we determined the genetic variability, phenotypic tolerance, DNA repair system activation, and dNTP pool upon treatment with current antibiotics using Mycobacterium smegmatis. Whole-genome sequencing revealed no significant increase in mutation rates after prolonged exposure to first-line antibiotics. However, the phenotypic fluctuation assay indicated rapid adaptation to antibiotics mediated by non-genetic factors. The upregulation of DNA repair genes, measured using qPCR, suggests that genomic integrity may be maintained through the activation of specific DNA repair pathways. Our results, indicating that antibiotic exposure does not result in de novo adaptive mutagenesis under laboratory conditions, do not lend support to the model suggesting antibiotic resistance development through drug pressure-induced microevolution.

Genetic stability of Mycobacterium smegmatis under the stress of first-line antitubercular agents.

The sustained success of Mycobacterium tuberculosis as a pathogen arises from its ability to persist within macrophages for extended periods and its limited responsiveness to antibiotics. Furthermore, the high incidence of resistance to the few available antituberculosis drugs is a significant concern, especially since the driving forces of the emergence of drug resistance are not clear. Drug-resistant strains of Mycobacterium tuberculosis can emerge through de novo mutations, however, mycobacterial mutation rates are low. To unravel the effects of antibiotic pressure on genome stability, we determined the genetic variability, phenotypic tolerance, DNA repair system activation, and dNTP pool upon treatment with current antibiotics using Mycobacterium smegmatis. Whole-genome sequencing revealed no significant increase in mutation rates after prolonged exposure to first-line antibiotics. However, the phenotypic fluctuation assay indicated rapid adaptation to antibiotics mediated by non-genetic factors. The upregulation of DNA repair genes, measured using qPCR, suggests that genomic integrity may be maintained through the activation of specific DNA repair pathways. Our results, indicating that antibiotic exposure does not result in de novo adaptive mutagenesis under laboratory conditions, do not lend support to the model suggesting antibiotic resistance development through drug pressure-induced microevolution.

Evidence of horizontal gene transfer and environmental selection impacting antibiotic resistance evolution in soil-dwelling Listeria

Soil is an important reservoir of antibiotic resistance genes (ARGs) and understanding how corresponding environmental changes influence their emergence, evolution, and spread is crucial. The soil-dwelling bacterial genus Listeria, including L. monocytogenes, the causative agent of listeriosis, serves as a key model for establishing this understanding. Here, we characterize ARGs in 594 genomes representing 19 Listeria species that we previously isolated from soils in natural environments across the United States. Among the five putatively functional ARGs identified, lin, which confers resistance to lincomycin, is the most prevalent, followed by mprF, sul, fosX, and norB. ARGs are predominantly found in Listeria sensu stricto species, with those more closely related to L. monocytogenes tending to harbor more ARGs. Notably, phylogenetic and recombination analyses provide evidence of recent horizontal gene transfer (HGT) in all five ARGs within and/or across species, likely mediated by transformation rather than conjugation and transduction. In addition, the richness and genetic divergence of ARGs are associated with environmental conditions, particularly soil properties (e.g., aluminum and magnesium) and surrounding land use patterns (e.g., forest coverage). Collectively, our data suggest that recent HGT and environmental selection play a vital role in the acquisition and diversification of bacterial ARGs in natural environments.

The impact of the virus on Salmonella pathogenicity islands' development of antibiotic resistance

The impact of the virus on Salmonella pathogenicity islands' development of antibiotic resistance

Identifying how drug efflux mechanisms impact Acinetobacter baumannii evolutionary paths to ciprofloxacin resistance

Acinetobacter baumannii is a multi-drug resistant pathogen commonly found in clinical settings. This pathogen frequently uses efflux pumps to mitigate antibiotic treatment stress and eliminate the drug. When A. baumannii is exposed to antibiotics, it often develops mutations in the efflux pump regulator genes, causing an increase in efflux pump production. We hypothesize that efflux is a key pathway that leads to treatment failure in A. baumannii infections. The extent to which increasing drug efflux impacts other cellular functions remains unknown. To identify how efflux pump mutations impact growth, resistance, and evolvability, wildtype A. baumannii laboratory strain 17978UN, along with four mutants of this strain, each with a single nucleotide polymorphism (SNP) in an efflux pump regulator (adeL L341R, adeN I49N, adeR D23Y, and adeS R152S), were propagated in the presence of antibiotic and an efflux pump inhibitor to place selective pressure on the isolates. SNPs increase the production of efflux pumps; inhibiting efflux ability will determine if the effect of each SNP is nullified. All evolved populations demonstrated differences in fitness and antibiotic resistance in comparison to their respective ancestors; the extent of adaptation affecting each phenotype was highly dependent on the regulator that was mutated. Counterintuitively, efflux inhibitors also placed stress on wild-type A. baumannii which leads to antibiotic resistance. These results demonstrate that efflux regulator mutations can influence population adaptability and cause treatment failure. Understanding the role that different efflux systems play in treatment failure and drug resistance evolution will be instrumental in developing treatment strategies that hinder the development of antibiotic resistance.

Antibiotic Residues in Milk and Milk-Based Products Served in Kuwait Hospitals: Multi-Hazard Risk Assessment.

Antimicrobial resistance (AMR) poses a significant global health challenge affecting food safety and development. Residues of antibiotics in food from animal sources, particularly milk, contribute to the development and spread of AMR, alter intestinal microbiota, and potentially lead to allergies, serious health conditions, and environmental and technological problems within the dairy industry. Therefore, this study investigated the residue levels of veterinary drugs from β-lactam antibiotics and tetracyclines in milk and milk products and assessed human health risks. Two hundred milk and milk product samples (pasteurized milk, sterile milk, soft white cheese, and processed cheese, 50 each) were collected from different hospitals in the State of Kuwait and screened for antibiotic residues using a microbial inhibition assay (Delvotest SP-NT) and high-performance liquid chromatography (HPLC). Delvotest SP-NT and HPLC analyses showed that 30, 28, 26, and 24% of the pasteurized milk, sterilized milk, white soft cheese, and processed cheese samples tested positive for antibiotic residues. Forty-eight milk and cheese samples were confirmed as positive by both methods, and six samples initially found to be negative by Delvotest SP-NT were confirmed as positive by HPLC. Multi-antibiotic residues were detected in five samples by using HPLC. The kappa coefficient (0.921; p < 0.0001) revealed complete concordance between the HPLC and Delvotest SP-NT results. Ampicillin was the most abundant residue in the positive samples (31.48%), ranging from 2.44 to 3.89 μg/L, with an overall mean concentration of 3.492 ± 0.094 μg/L, followed by tetracycline and oxytetracycline (27.78% each), ranging from 54.13 to 220.3 μg/L and from 41.55 to 160.7 μg/L, with mean concentrations of 129.477 ± 14.22 and 91.86 ± 9.92 μg/L, respectively. The amoxicillin levels in the samples (12/54; 22.22%) ranged from 3.11 to 5.5 μg/L, with an overall mean concentration of 3.685 ± 0.186 μg/L. The maximum concentrations of ampicillin, amoxicillin, and tetracycline were detected in processed cheese with mean concentrations of 3.89 ± 0.28 µg/L, 3.95 ± 0.15 µg/L, and 170.3 ± 0.27 µg/L, respectively. Pasteurized milk contained the maximum concentrations of oxytetracycline, with a mean concentration of 120.45 ± 0.25 µg/L. The tetracycline residues exceeded the standard maximum residue limits (MRLs; 100 µg/L) in 6% of both pasteurized and sterilized milk samples, and in 4% of processed cheese. Additionally, the oxytetracycline levels in pasteurized milk (6%) and amoxicillin levels in processed cheese (2%) were higher than the permitted MRLs (100 µg/L and 4 µg/L, respectively). Furthermore, the antibiotic residues detected in 12.5% (25/200) of the samples were close to standard permissible MRL limits for ampicillin (5%), amoxicillin and oxytetracycline (3% each), and tetracycline (1.5%). Hazard quotients, which compare the standard acceptable daily intake (ADI) to the estimated daily exposure (EDI), indicated that the overall risk associated with antibiotic residues in these dairy products is low. The EDI was lower than the ADI for the tested antibiotics, indicating an elevated safety margin. While the overall hazard quotients are low, the potential for the development of antibiotic resistance due to long-term exposure to low levels of antibiotics should be considered. Hence, strict regulations and enforcement are necessary to prevent excessive residue levels and to promote responsible antibiotic use in dairy production. Regular monitoring of antibiotic residues in dairy products is essential for ensuring consumer safety.

A possible alternative to antibacterial therapy in the treatment of acute rhinosinusitis

High incidence of acute rhinosinusitis in a population remains one of the topical issues in practical otolaryngology. Statistical data show an increasing trend towards transition of acute rhinosinusitis in patients into chronic rhinosinusitis. According to literary sources, the emergence of bacterial resistance to antibiotics is as a rule the major reason of protracted course of the disease. Unreasonable antibiotics prescription, irrational use and uncontrolled intake result in the rapid development of antibiotic resistance. In this context, the use of herbal medicines having not only antibacterial, but also mucolytic, fungicidal, antioxidant effects in the complex therapy is a modern solution for disease management. Respero Myrtol, a standardized myrtol-based medicine, has taken its rightful place in the therapy. This article is aimed to investigate the possibilities of the effective use of medicine containing standardized myrtol as its main ingredient in the treatment of acute rhinosinusitis (based on the review of literature). Research materials included scientific articles on aspects of acute rhinosinusitis in otorhinolaryngology practice that were published in domestic specialized periodicals of eLIBRARY and scientific databases Scopus, Web of Science, Medline from 2014 to 2024. The published literature was analysed using the cause-and-effect technique. A clinical example was dis-cussed. With regard to the analysis of scientific literature, a brief overview of the epidemiology, etiology, predisposing factors for the development, diagnosis and treatment of acute rhinosinusitis was provided. The article addresses relevant socio-economic issues related to acute rhinosinusitis, the problem of antibiotic resistance. The issues of improving acute rhinosinusitis treatments using a standardized myrtol medicine in complex therapy as an alternative to antibiotic therapy were brought to attention. As a result, the authors concluded that the use of Respero Myrtol contributes to the rapid relief of clinical symptoms of acute rhinosinusitis, improves the patient’s quality of life, and can be advised as an alternative to antibiotic therapy in uncomplicated course of the disease.

Modelling the impacts generated by reclaimed wastewater reuse in agriculture: From literature gaps to an integrated risk assessment in a One Health perspective

The reuse of reclaimed wastewater is increasingly recognized as a viable alternative water source for irrigation. Its application, whether direct or indirect, impacts several interconnected compartments, including groundwater, surface water, soil, crops, and humans. Reclaimed wastewater provides essential resources for crops, like water and nutrients. However, it also introduces pathogens, and contaminants of emerging concern (CECs), defined as chemicals that may pose risks to human health and ecosystems but are not yet fully regulated, such as pharmaceuticals and personal care products, among others. Additionally, reclaimed wastewater may contain antibiotic-resistant bacteria (ARBs) and disinfection by-products (DBPs), all of which present potential health and environmental risks. Therefore, regulatory bodies stress the need for preventive risk assessments to ensure safe reuse.This paper critically reviews available models for assessing the impacts of reclaimed wastewater reuse in agriculture. It identifies gaps in current modelling approaches and outlines future research directions. Key areas requiring further investigation include the fate and transfer of CECs, ARBs and DBPs, and the co-occurrence of multiple risks in such interconnected systems, especially in the indirect reuse. To address these gaps, we proposed a simplified approach to integrate three types of risk associated with CECs in indirect reuse, focusing on risks posed by antibiotics and other pharmaceuticals: human health risk, environmental risk and risk from antibiotic resistance development. This approach aids in identifying the most critical endpoints within the One Health approach, supporting (i) CECs prioritization in regulations based on their critical endpoints and (ii) the adoption of CEC-specific mitigation measures.

Removal of Pharmaceutically Active Compounds from Hospital Wastewater with Ozonation

Hospital wastewater includes many pharmaceutically active compounds (PhACs). Since this resulted in both PhACs distribution to the environment and antibiotic resistance development of microorganisms, on-site treatment of hospital wastewater has gained importance. In this study, the removal of 21 PhACs consisting of 12 parent compounds and 9 main metabolites from hospital wastewater was researched by ozonation. In this context, commonly used analgesics (paracetamol, diclofenac, ibuprofen, and naproxen, 4'-hydroxydiclofenac, 5-hydroxydiclofenac, 1-hydroxyibuprofen, 2-hydroxyibuprofen, carboxyibuprofen, (S)-O-desmethyl naproxen) and antibiotics (ciprofloxacin, sulfamethoxazole, trimethoprim, erythromycin, metronidazole, clarithromycin, azithromycin, clindamycin, N-acetyl-sulfamethoxazole, sulfamethoxazole-β-D-glucuronide, clindamycin sulfoxide) were selected. PhAC analyses were conducted with HPLC/MS-MS. The ozonation dose was between 0.05-5.0 mg O3/mg COD. In real hospital wastewater, many of the selected PhACs were detected and total analgesic and antibiotic were determined as 22.9 and 40.6 µg/L, respectively. The results showed that detected PhACs were completely removed at 1.5 mg O3/mg COD. Additionally, COD removal was determined as 48% in this ozone dose. The result of the study shows that pre-oxidation of hospital wastewater is an effective method in terms of on-site pretreatment of PhACs.