The resistance mechanisms of bacteria against ciprofloxacin and new approaches for enhancing the efficacy of this antibiotic

Research on NiTi instruments combined with ultrasonic irrigation and multiantibiotic paste in root canal therapy of periapical inflammation in deciduous teeth

Pain often occurs after root canal treatment due to unavoidable mechanical or chemical damage. The purpose of the present study was to investigate the efficacy of a nickel-titanium (NiTi) device combined with ultrasonic irrigation and multiple antibiotic creams in the treatment of periapical inflammation of deciduous teeth, so as to improve the understanding of root canal treatment and optimize clinical practice. Evaluation of efficacy was conducted using X-rays and the Visual Analog Scale. This treatment significantly reduced pain and also improved patient compliance and treatment outcomes. The findings of the present study may have scientific and clinical significance for optimizing root canal treatment in pediatric dentistry and requires further in-depth research in clinical practice. These outcomes may provide potential new ideas and directions for improving patients' quality of life and the efficacy of clinical treatment and have further impacts on future related research and medical practice.

Enhanced binding interaction and antibacterial inhibition for nanometal oxide particles activated with Aloe Vulgarize through one-pot ultrasonication techniques

The interaction of green zinc oxide nanoparticles (ZnO NPs) with bacterial strains are still scarcely reported. This work was conducted to study the green-one-pot-synthesized ZnO NPs from the Aloe Vulgarize (AV) leaf peel extract assisted with different sonication techniques followed by the physicochemical, biological activities and molecular docking studies. The NPs structure was analyzed using FTIR, UV-vis and EDX. The morphology, particle size and crystallinity of ZnO NPs were identified using FESEM and XRD. It was found that the formed flower-like structure with sharp edge and fine size of particulates in ZnO NPs/AV could enhance the bacterial inhibition. The minimum inhibitory concentration (MIC) for all the tested bacterial strains is at 3.125 µg/ml and the bacterial growth curve are dependent on the ZnO NPs dosage. The results of disc diffusion revealed that the ZnO NPs/AV possess better antibacterial effect with bigger ZOI due to the presence of AV active ingredient. The molecular docking between active ingredients of AV in the NPs with the protein of IFCM and 1MWU revealed that low binding energy (Ebind = -6.56 kcal/mol and -8.99 kcal/mol, respectively) attributes to the excessive hydrogen bond from AV that highly influenced their interaction with the amino acid of the selected proteins. Finally, the cytotoxicity test on the biosynthesized ZnO NPs with concentration below 20 µg/ml are found nontoxic on the HDF cell. Overall, ZnO NPs/20 % AV (probe sonication) is considered as the best synthesis option due to its efficient one-pot method, short sonication time but own the best antibacterial effect.

Recent efforts in the development of glycoconjugate vaccine and available treatment for tuberculosis

Tuberculosis (TB) continues to pose a grave threat to global health, despite relentless eradication efforts. In 1882, Robert Koch discovered that Mycobacterium tuberculosis (Mtb) is the bacterium responsible for causing tuberculosis. It is a fact that tuberculosis has claimed the lives of more than one billion people in the last few decades. It is imperative that we must take immediate and effective action to increase resources for TB research and treatment. Effective TB treatments demand an extensive investment of both time and finances, often requiring 6-9 months of rigorous antibiotic therapy. The most efficient way to control tuberculosis is by receiving a childhood Bacillus Calmette-Guérin (BCG) vaccination. Despite years of research on vaccine development, we still do not have any new approved vaccine for tuberculosis, except BCG, which is partially effective in young children. This review discusses briefly the available treatment for tuberculosis and remarkable advancements in glycoconjugate-based TB vaccine developments in recent years (2013-2024) and offers valuable direction for future research priorities.

Synthesis and characterisation of antimicrobial metal-organic frameworks as multi-drug carriers

Antibiotic resistance is a significant global concern, necessitating the development of either new antibiotics or advanced delivery methods. With this in mind, we report on the synthesis and characterisation of a new family of Metal-Organic Frameworks (MOFs), OnG6 MOFs, designed to act as multi-drug carriers for bacterial infection treatment. OnG6 is based on the pro-drug 4,4'-azodisalicylic acid (AZDH4), which in vivo produces two equivalents of para-aminosalicylic acid (ASA), a crucial drug for M. tuberculosis treatment. X-ray and computational studies revealed that OnG6 MOFs are mesoporous MOFs with etb topology and an [M2(AZD)] formula (M = Zn, OnG6-Zn; Mg, OnG6-Mg; Cu, OnG6-Cu; and Co, OnG6-Co), featuring 1-dimensional channel type pores of 25 Å diameter. OnG6 MOFs are the first reported MOFs bearing the ligand AZDH4, joining the family of mesoporous MOFs arranged in a honeycomb pattern. They absorb isoniazid (INH) and ciprofloxacin (CIPRO) with the former being a specific antibiotic for M. tuberculosis, and the latter being a broader-spectrum antibiotic. The stability of the MOFs and their capacity for antibiotic uptake depend on the nature of the metal ion, with OnG6-Mg demonstrating the highest drug absorption. The antimicrobial activity of these species was assessed against S. aureus and E. coli, revealing that the carriers containing CIPRO displayed optimal efficacy.

The effects of submicron-textured surface topography on antibiotic efficacy against biofilms

Submicron-textured surfaces have been a promising approach to mitigate biofilm development and control microbial infection. However, the use of the single surface texturing approach is still far from ideal for achieving complete control of microbial infections on implanted biomedical devices. The use of a surface topographic modification that might improve the utility of standard antibiotic therapy could alleviate the complications of biofilms on devices. In this study, we characterized the biofilms of Staphylococcus aureus and Pseudomonas aeruginosa on smooth and submicron-textured polyurethane surfaces after 1, 2, 3, and 7 days, and measured the efficacy of common antibiotics against these biofilms. Results show that the submicron-textured surfaces significantly reduced biofilm formation and growth, and that the efficacy of antibiotics against biofilms grown on textured surfaces was improved compared with smooth surfaces. The antibiotic efficacy appears to be related to the degree of biofilm development. At early time points in biofilm formation, antibiotic treatment reveals reasonably good antibiotic efficacy against biofilms on both smooth and textured surfaces, but as biofilms mature, the efficacy of antibiotics drops dramatically on smooth surfaces, with lesser decreases seen for the textured surfaces. The results demonstrate that surface texturing with submicron patterns is able to improve the use of standard antibiotic therapy to treat device-centered biofilms by slowing the development of the biofilm, thereby offering less resistance to antibiotic delivery to the bacteria within the biofilm community.

A metabolomics pipeline highlights microbial metabolism in bloodstream infections

The growth of antimicrobial resistance (AMR) highlights an urgent need to identify bacterial pathogenic functions that may be targets for clinical intervention. Although severe infections profoundly alter host metabolism, prior studies have largely ignored microbial metabolism in this context. Here, we describe an iterative, comparative metabolomics pipeline to uncover microbial metabolic features in the complex setting of a host and apply it to investigate gram-negative bloodstream infection (BSI) in patients. We find elevated levels of bacterially derived acetylated polyamines during BSI and discover the enzyme responsible for their production (SpeG). Blocking SpeG activity reduces bacterial proliferation and slows pathogenesis. Reduction of SpeG activity also enhances bacterial membrane permeability and increases intracellular antibiotic accumulation, allowing us to overcome AMR in culture and in vivo. This study highlights how tools to study pathogen metabolism in the natural context of infection can reveal and prioritize therapeutic strategies for addressing challenging infections.

Site-Specific Antimicrobial Activity of a Dual-Responsive Ciprofloxacin Prodrug

Bacterial infections create distinctive microenvironments with a unique mix of metabolites and enzymes compared with healthy tissues that can be used to trigger the activation of antibiotic prodrugs. Here, a single and dual prodrug masking the C3 carboxylate and C7 piperazine of the fluoroquinolone, ciprofloxacin, responsive to nitroreductase (NTR) and/or hydrogen sulfide (H2S), was developed. Masking both functional groups reduced the activity of the prodrug against Staphylococcus aureus and Escherichia coli, increasing its minimum inhibitory concentration (MIC) by ∼512-fold (S. aureus) and ∼8000-fold (E. coli strains), while masking a single group only increased the MIC by ∼128-fold. Bacteria subjected to prolonged prodrug exposure did not show any increase in resistance. Triggering assays demonstrated the conversion of prodrugs to ciprofloxacin, and in a murine infection model, responsive prodrugs showed antibacterial activity comparable to that of ciprofloxacin, suggesting in vivo activation of prodrugs. Thus, the potential for site-specific antibiotic treatment with reduced threat of resistance is demonstrated.

Repression of resistance mechanisms of Pseudomonas aeruginosa: implications of the combination of antibiotics and phytoconstituents

Antimicrobial resistance is a prevalent problem witnessed globally and creating an alarming situation for the treatment of infections caused by resistant pathogens. Available armaments such as antibiotics often fail to exhibit the intended action against resistant pathogens, leading to failure in the treatments that are causing mortality. New antibiotics or a new treatment approach is necessary to combat this situation. P. aeruginosa is an opportunistic drug resistant pathogen and is the sixth most common cause of nosocomial infections. P. aeruginosa due to its genome organization and other factors are exhibiting resistance against drugs. Bacterial biofilm formation, low permeability of outer membrane, the production of the beta-lactamase, and the production of several efflux systems limits the antibacterial potential of several classes of antibiotics. Combination of phytoconstituents with antibiotics is a promising strategy to combat multidrug resistant P. aeruginosa. Phytoconstituents such as flavonoids, terpenoids, alkaloids, polypeptides, phenolics, and essential oils are well known antibacterial agents. In this review, the activity of combination of the phytoconstituents and antibiotics, and their corresponding mechanism of action was discussed elaborately. The combination of antibiotics and plant-derived compounds exhibited better efficacy compared to antibiotics alone against the antibiotic resistance P. aeruginosa infections.

Polymeric nanoparticles delivery circumvents bacterial resistance to ciprofloxacin

OBJECTIVE

The efficient inhibition of bacteria and their by-products from infected root canals is hampered by the limitations of traditional root canal disinfection strategies, bacterial resistance to antibiotic drugs, and regenerative endodontics. Polymeric nanoparticles nanocarrier for controlling antibiotic drug delivery were used to overcome the limitations encountered in endodontics treatment.

BACKGROUND

Several polymeric nanoparticles have been used for the delivery of ciprofloxacin drug. The application of poly (ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) (PEG-PLGA) nanoparticles has highlighted the clean and safe delivery of ciprofloxacin (CIP) hydrophilic drug for endodontics treatment. PEG/PLGA was prepared using the solid/oil/water method and the CIP was loaded into polymeric nanoparticles via an ion pairing agent.

RESULTS

The CIP-loaded PEG-PLGA nanoparticles have a spherical shape with a 120 ± 0.43 nm size, the CIP encapsulating efficiency was 63.26 ± 9.24% with a loading content of 7.75 ± 1.13%, and sustained release was achieved over 168 h which followed Higuchi model with a non-Fickian mechanism. Moreover, CIP-loaded PEG-PLGA had low cytotoxicity to the stem cells of the apical papilla.

CONCLUSION

The results conclude invigorating future perspectives of polymeric nanoparticles for a wide range of drug delivery for various disease treatments. It's anticipated that these polymeric nanoparticles may divert new expectations in the future for topical antibiotic drug delivery with discrete intracellular medicament, and a safe and clean environment.

Molecular characterization of Staphylococcus aureus isolated from hospital-acquired infections in Ilam, Iran

OBJECTIVE

This research study was undertaken to investigate antimicrobial resistance patterns and the prevalence of hospital-acquired infections (HAIs). The study focuses on common microorganisms responsible for HAIs and explores emerging challenges posed by antimicrobial drug-resistant isolates.

METHODS

A comprehensive analysis of 123 patients with HAIs, hospitalized in surgical department and intensive care unit (ICU) at Imam Khomeini Hospital, Ilam, Iran, was conducted over a six-month period. Pathogenic bacterial isolates, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Staphylococcus aureus (VRSA), were isolated and subjected to antibiotic susceptibility testing.

RESULTS

The study findings revealed a significant prevalence of multidrug-resistant (MDR) isolates, of which 73.3% were MRSA. Notably, 6.7% of S. aureus isolates exhibited resistance to vancomycin, indicating the emergence of VRSA. Respiratory infections were identified as the most prevalent HAI, constituting 34.67% of cases, often arising from extended ICU stays and invasive surgical procedures. Furthermore, patients aged 60 and above, particularly those associated with MDR, exhibited higher vulnerability to HAI.

CONCLUSIONS

This research sheds light on the intricate interplay between drug resistance and HAI, highlighting the imperative role of rational antibiotic use and infection control in addressing this critical healthcare challenge.

Ciprofloxacin-Loaded Inhalable Formulations against Lower Respiratory Tract Infections: Challenges, Recent Advances, and Future Perspectives

Inhaled ciprofloxacin (CFX) has been investigated as a treatment for lower respiratory tract infections (LRTIs) associated with cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), and bronchiectasis. The challenges in CFX effectiveness for LRTI treatment include poor aqueous solubility and therapy resistance. CFX dry powder for inhalation (DPI) formulations were well-tolerated, showing a remarkable decline in overall bacterial burden compared to a placebo in bronchiectasis patients. Recent research using an inhalable powder combining Pseudomonas phage PEV20 with CFX exhibited a substantial reduction in bacterial density in mouse lungs infected with clinical P. aeruginosa strains and reduced inflammation. Currently, studies suggest that elevated biosynthesis of fatty acids could serve as a potential biomarker for detecting CFX resistance in LRTIs. Furthermore, inhaled CFX has successfully addressed various challenges associated with traditional CFX, including the incapacity to eliminate the pathogen, the recurrence of colonization, and the development of resistance. However, further exploration is needed to address three key unresolved issues: identifying the right patient group, determining the optimal treatment duration, and accurately assessing the risk of antibiotic resistance, with additional multicenter randomized controlled trials suggested to tackle these challenges. Importantly, future investigations will focus on the effectiveness of CFX DPI in bronchiectasis and COPD, aiming to differentiate prognoses between these two conditions. This review underscores the importance of CFX inhalable formulations against LRTIs in preclinical and clinical sectors, their challenges, recent advancements, and future perspectives.

Novel fibrous Ag(NP) decorated clay-polymer composite: Implications in water purification contaminated with predominant micro-pollutants and bacteria

Due to the potential harm caused by emerging micro-pollutants to living organisms, contaminating water supplies by micro-pollutants like EDCs, pharmaceuticals, and microorganisms has become a concern in many countries. Considering both microbiological and micro-pollutant exposure risks associated with water use for agricultural/or household purposes, it is imperative to create a strategy for improving pollutant removal from treated wastewater that is both effective and affordable. Natural clay minerals efficiently remove contaminants from wastewater, though the pristine clay has less affinity to several organic pollutants. Hydrophilic polymers, viz., poly(ethylene glycol) (PEG), improve the dispersion of particles, flocculation processes, and surface properties. In this study, PEG grafted with attapulgite, thereby providing a high-specific surface-area, mesoporous materials for the adsorption of micro-pollutants like ciprofloxacin (CIP) and 17α-ethinylestradiol (EE2) at high rates. A gentle washing process regenerates the clay-polymer material several times with no performance loss, and the natural water implications show fair applicability of solid in decontaminating the CIP and EE2 in an aqueous medium. Further, greenly synthesized silver nanoparticles in situ disperse with the clay polymer efficiently remove the gram-positive and gram-negative bacterium viz., Bacillus subtilis, and Pseudomonas aeruginosa, which are commonly persistent in aquatic environments. The clay polymer outperformed a modified clay composite to eliminate microorganisms and organic micro-pollutants in significant quantities quickly. These results clearly show the importance of fibrous clay-polymer composite for water purification technologies.

Veterinary antibiotics differ in phytotoxicity on oilseed rape grown over a wide range of concentrations

Residues of veterinary antibiotics are a worldwide problem of increasing concern due to their persistence and diverse negative effects on organisms, including crops, and limited understanding of their phytotoxicity. Therefore, this study aimed to compare the phytotoxic effects of veterinary antibiotics tetracycline (TC) and ciprofloxacin (CIP) applied in a wide range of concentrations on model plant oilseed rape (Brassica napus). Overall phytotoxicity of 1-500 mg kg-1 of TC and CIP was investigated based on morphological, biochemical, and physiological plant response. Photosystem II (PSII) performance was suppressed by TC even under environmentally relevant concentration (1 mg kg-1), with an increasing effect proportionally to TC concentration in soil. In contrast, CIP was found to be more phytotoxic than TC when applied at high concentrations, inducing a powerful oxidative burst, impairment of photosynthetic performance, collapse of antioxidative protection and sugar metabolism, and in turn, complete growth retardation at 250 and 500 mg kg-1 CIP treatments. Results of our study suggest that TC and CIP pollution do not pose a significant risk to oilseed rapes in many little anthropogenically affected agro-environments where TC or CIP concentrations do not exceed 1 mg kg-1; however, intensive application of manure with high CIP concentrations (more than 50 mg kg-1) might be detrimental to plants and, in turn, lead to diminished agricultural production and a potential risk to human health.

Evaluation of drug release efficiency and antibacterial property of a pH-responsive dextran-based silver nanocomposite hydrogel

The bioavailability of curcumin (CUR), a highly lipophilic and commonly used anticancer drug, is mainly affected by its poor solubility in aqueous environment and quick metabolism. These challenges can be met by employing delivery systems. Nanocomposite materials have been used as delivery systems to enhance the solubility and dissolution rate of the drug. This study aims to develop dextran-graft-poly(4-acryloylmorpholine) silver nanocomposite using a microwave-assisted method to evaluate its drug-release efficiency and antimicrobial activity. The materials were characterized by FT-IR, FE-SEM, EDS, XRD, HR-TEM, TGA, and BET techniques. Drug loading and release efficiency were evaluated using CUR as the model drug. The swelling and drug release studies were conducted in buffer solutions of pH 1.2 and 7.4. Staphylococcus aureus and Escherichia coli were employed to evaluate the antibacterial activity. The cytotoxicity was assessed by MTT assay against the breast MCF-10. Higher swelling and drug release were observed at pH 1.2 than 7.4. Nanocomposite hydrogel exhibited antibacterial activity against the tested bacterial strains. Cytotoxicity study proved the safety of the developed matrix. The results suggest the developed nanocomposite hydrogel to be a promising polymer matrix for the sustained release of CUR for cancer treatment that requires infectious control.

Pharmacokinetics of Enrofloxacin in Plasma, Urine, and Feces of Donkey (Equus asinus) after a Single Intragastric Administration

Enrofloxacin is a broad-spectrum antimicrobial agent, but the study of its pharmacokinetics/pharmacodynamics (PKs/PDs) in donkeys is rarely reported. The present study aimed to investigate the pharmacokinetics of enrofloxacin administered intragastrically, and to study the pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin in plasma, urine, and feces, and the PK/PD parameters were investigated to provide a rationale for enrofloxacin treatment in donkeys. A total of five healthy donkeys were selected for intragastric administration of 7.5 mg·kg-1 BW of enrofloxacin by gavage, and blood, urine, and fecal samples were collected. The results showed that the elimination half-life of plasma enrofloxacin was 11.40 ± 6.40 h, Tmax was 0.55 ± 0.12 h, Cmax was 2.46 ± 0.14 mg·L-1, AUC0-∞ was 10.30 ± 3.37 mg·L-1·h, and mean residence time (MRT) was 7.88 ± 1.26 h. The Tmax of plasma ciprofloxacin was 0.52 ± 0.08 h, Cmax was 0.14 ± 0.03 mg·L-1, and AUC0-∞ was 0.24 ± 0.16 mg·L-1·h. Urinary Cmax was 38.18 ± 8.56 mg·L-1 for enrofloxacin and 15.94 ± 4.15 mg·L-1 for ciprofloxacin. The total enrofloxacin and ciprofloxacin recovered amount in urine was 7.09 ± 2.55% of the dose for 144 h after dosing. The total enrofloxacin and ciprofloxacin recovered amount in feces was 25.73 ± 10.34% of the dose for 144 h after dosing. PK/PD parameters were also examined in this study, based on published MICs. In conclusion, 7.5 mg/kg BW of enrofloxacin administered intragastrically to donkeys was rapidly absorbed, widely distributed, and slowly eliminated in their bodies, and was predicted to be effective against bacteria with MICs < 0.25 mg·L-1.

Research Progress on the Combination of Quorum-Sensing Inhibitors and Antibiotics against Bacterial Resistance

Bacterial virulence factors and biofilm development can be controlled by the quorum-sensing (QS) system, which is also intimately linked to antibiotic resistance in bacteria. In previous studies, many researchers found that quorum-sensing inhibitors (QSIs) can affect the development of bacterial biofilms and prevent the synthesis of many virulence factors. However, QSIs alone have a limited ability to suppress bacteria. Fortunately, when QSIs are combined with antibiotics, they have a better therapeutic effect, and it has even been demonstrated that the two together have a synergistic antibacterial effect, which not only ensures bactericidal efficiency but also avoids the resistance caused by excessive use of antibiotics. In addition, some progress has been made through in vivo studies on the combination of QSIs and antibiotics. This article mainly expounds on the specific effect of QSIs combined with antibiotics on bacteria and the combined antibacterial mechanism of some QSIs and antibiotics. These studies will provide new strategies and means for the clinical treatment of bacterial infections in the future.

Antibacterial, Fatigue-Resistant, and Self-Healing Dressing from Natural-Based Composite Hydrogels for Infected Wound Healing

The treatment of infected wounds faces substantial challenges due to the high incidence and serious infection-related complications. Natural-based hydrogel dressings with favorable antibacterial properties and strong applicability are urgently needed. Herein, we developed a composite hydrogel by constructing multiple networks and loading ciprofloxacin for infected wound healing. The hydrogel was synthesized via a Schiff base reaction between carboxymethyl chitosan and oxidized sodium alginate, followed by the polymerization of the acrylamide monomer. The resultant hydrogel dressing possessed a good self-healing ability, considerable compression strength, and reliable compression fatigue resistance. In vitro assessment showed that the composite hydrogel effectively eliminated bacteria and exhibited an excellent biocompatibility. In a model of Staphylococcus aureus-infected full-thickness wounds, wound healing was significantly accelerated without scars through the composite hydrogel by reducing wound inflammation. Overall, this study opens up a new way for developing multifunctional hydrogel wound dressings to treat wound infections.

Evolution of Resistance against Ciprofloxacin, Tobramycin, and Trimethoprim/Sulfamethoxazole in the Environmental Opportunistic Pathogen Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an opportunistic pathogen that produces respiratory infections in immunosuppressed and cystic fibrosis patients. The therapeutic options to treat S. maltophilia infections are limited since it exhibits resistance to a wide variety of antibiotics such as β-lactams, aminoglycosides, tetracyclines, cephalosporins, macrolides, fluoroquinolones, or carbapenems. The antibiotic combination trimethoprim/sulfamethoxazole (SXT) is the treatment of choice to combat infections caused by S. maltophilia, while ceftazidime, ciprofloxacin, or tobramycin are used in most SXT-resistant infections. In the current study, experimental evolution and whole-genome sequencing (WGS) were used to examine the evolutionary trajectories of S. maltophilia towards resistance against tobramycin, ciprofloxacin, and SXT. The genetic changes underlying antibiotic resistance, as well as the evolutionary trajectories toward that resistance, were determined. Our results determine that genomic changes in the efflux pump regulatory genes smeT and soxR are essential to confer resistance to ciprofloxacin, and the mutation in the rplA gene is significant in the resistance to tobramycin. We identified mutations in folP and the efflux pump regulator smeRV as the basis of SXT resistance. Detailed and reliable knowledge of ciprofloxacin, tobramycin, and SXT resistance is essential for safe and effective use in clinical settings. Herein, we were able to prove once again the extraordinary ability that S. maltophilia has to acquire resistance and the importance of looking for alternatives to combat this resistance.

A review of the mechanisms that confer antibiotic resistance in pathotypes of E. coli

The dissemination of antibiotic resistance in Escherichia coli poses a significant threat to public health worldwide. This review provides a comprehensive update on the diverse mechanisms employed by E. coli in developing resistance to antibiotics. We primarily focus on pathotypes of E. coli (e.g., uropathogenic E. coli) and investigate the genetic determinants and molecular pathways that confer resistance, shedding light on both well-characterized and recently discovered mechanisms. The most prevalent mechanism continues to be the acquisition of resistance genes through horizontal gene transfer, facilitated by mobile genetic elements such as plasmids and transposons. We discuss the role of extended-spectrum β-lactamases (ESBLs) and carbapenemases in conferring resistance to β-lactam antibiotics, which remain vital in clinical practice. The review covers the key resistant mechanisms, including: 1) Efflux pumps and porin mutations that mediate resistance to a broad spectrum of antibiotics, including fluoroquinolones and aminoglycosides; 2) adaptive strategies employed by E. coli, including biofilm formation, persister cell formation, and the activation of stress response systems, to withstand antibiotic pressure; and 3) the role of regulatory systems in coordinating resistance mechanisms, providing insights into potential targets for therapeutic interventions. Understanding the intricate network of antibiotic resistance mechanisms in E. coli is crucial for the development of effective strategies to combat this growing public health crisis. By clarifying these mechanisms, we aim to pave the way for the design of innovative therapeutic approaches and the implementation of prudent antibiotic stewardship practices to preserve the efficacy of current antibiotics and ensure a sustainable future for healthcare.

Management of the Septic Wrist: A Systematic Review of Etiology and Therapeutic Strategies

Septic arthritis of the wrist can have severe deleterious effects on cartilage and bone if not promptly addressed. Expedient diagnosis and early medical intervention are important. The most effective strategy involves immediate arthrocentesis of the infected joint, enabling precise antibiotic selection based on joint fluid analysis. Diagnostic imaging is important in excluding fractures and identifying abscesses. This review explores the etiologic factors underlying septic wrist joint, identifying risk factors, and delineating optimal diagnosis and treatment approaches. The overarching goal is to impart valuable insights and guidance in the management of septic wrist joint, ensuring the highest quality patient care and optimal clinical outcomes.

Chronic toxicity of pharmaceuticals to the benthic green alga Closterium ehrenbergii

Pharmaceuticals in the environment have emerged to a topic of global concern. Since these substances are designed to be biologically active, hazardous effects on non-target organisms are frequently reported. Here, the effects of five pharmaceuticals, one radiocontrast agent, and one degradation product on the freshwater green alga Closterium ehrenbergii were evaluated after chronic exposure of 168 h. Growth and maximum quantum yield (FV/FM) were used as endpoints and complemented by the assessment of morphology and chlorophyll fluorescence. We found that the tested antibiotics Ciprofloxacin and Ofloxacin impaired chloroplast integrity, resulting in a reduction of FV/FM from 0.1 mg/L. The disintegration of chloroplasts at higher concentrations (c = 0.3 and 0.8 mg/L, respectively) was visualized by brightfield and fluorescence microscopy. In contrast, Sulfamethoxazole interfered with cell division, leading to malformation of cells from 0.8 mg/L. Furthermore, the antibiotics exhibited a latency period of 72 h after which they started to reveal their true effects. Therefore, the importance of long-term toxicity testing is outlined in order to avoid underestimation of toxic effects of pharmaceuticals. Based on the EC10 values obtained, the antibiotics were considered to meet the criteria for classification as toxic to aquatic life with long lasting effects. The other test substances were found to exert no effects on C. ehrenbergii or only at very high concentrations and were classified as nontoxic.

Synthesis and Trace-Level Quantification of Mutagenic and Cohort-of-Concern Ciprofloxacin Nitroso Drug Substance-Related Impurities (NDSRIs) and Other Nitroso Impurities Using UPLC-ESI-MS/MS-Method Optimization Using I-Optimal Mixture Design

Globally, the pharmaceutical industry has been facing challenges from nitroso drug substance-related impurities (NDSRIs). In the current study, we synthesized and developed a rapid new UPLC-MS/MS method for the trace-level quantification of ciprofloxacin NDSRIs and a couple of N-nitroso impurities simultaneously. (Q)-SAR methodology was employed to assess and categorize the genotoxicity of all ciprofloxacin N-nitroso impurities. The projected results were positive, and the cohort of concern (CoC) for all three N-nitroso impurities indicates potential genotoxicity. AQbD-driven I-optimal mixture design was used to optimize the mixture of solvents in the method. The chromatographic resolution was accomplished using an Agilent Poroshell 120 Aq-C18 column (150 mm × 4.6 mm, 2.7 μm) in isocratic elution mode with 0.1% formic acid in a mixture of water, acetonitrile, and methanol in the ratio of 475:500:25 v/v/v at a flow rate of 0.5 mL/min. Quantification was carried out using triple quadrupole mass detection with electrospray ionization (ESI) in a multiple reaction monitoring technique. The finalized method was validated successfully, affording ICH guidelines. All N-nitroso impurities revealed excellent linearity over the concentration range of 0.00125-0.0250 ppm. The Pearson correlation coefficient of each N-nitroso impurity was >0.999. The method accuracy recoveries ranged from 93.98 to 108.08% for the aforementioned N-nitrosamine impurities. Furthermore, the method was effectively applied to quantify N-nitrosamine impurities simultaneously in commercially available formulated samples, with its efficiency recurring at trace levels. Thus, the current method is capable of determining the trace levels of three N-nitroso ciprofloxacin impurities simultaneously from the marketed tablet dosage forms for commercial release and stability testing.

Combating antimicrobial resistance: the silent war

Once hailed as miraculous solutions, antibiotics no longer hold that status. The excessive use of antibiotics across human healthcare, agriculture, and animal husbandry has given rise to a broad array of multidrug-resistant (MDR) pathogens, posing formidable treatment challenges. Antimicrobial resistance (AMR) has evolved into a pressing global health crisis, linked to elevated mortality rates in the modern medical era. Additionally, the absence of effective antibiotics introduces substantial risks to medical and surgical procedures. The dwindling interest of pharmaceutical industries in developing new antibiotics against MDR pathogens has aggravated the scarcity issue, resulting in an exceedingly limited pipeline of new antibiotics. Given these circumstances, the imperative to devise novel strategies to combat perilous MDR pathogens has become paramount. Contemporary research has unveiled several promising avenues for addressing this challenge. The article provides a comprehensive overview of these innovative therapeutic approaches, highlighting their mechanisms of action, benefits, and drawbacks.

Co-Delivery of Naringin and Ciprofloxacin by Oleic Acid Lipid Core Encapsulated in Carboxymethyl Chitosan/Alginate Nanoparticle Composite for Enhanced Antimicrobial Activity

A novel combination of antibiotic, ciprofloxacin (CIP) with herbal counterpart naringin (NAR) was encapsulated by an oleic acid lipid core and carboxymethyl chitosan (CM-CS)/Alginate (AG) nanoparticle composite (CIP + NAR-CM-CS/AG-NPs) for improved antimicrobial efficacy of antibiotic. Herein, this study explored the design and preparation of a composite system that enables to deliver both CIP and NAR from the oleic acid lipid core of CM-CS/AG nanoparticles using a nonsolvent ionic gelation technique. The nanoparticles (NPs) were fabricated with improved long-acting antimicrobial activity against E. coli and S. aureus. The optimized composition was investigated for physicochemical properties particle size, particle distribution, and ζ-potential. A diverse array of analytical tools was employed to characterize the optimized formulation including DSC, XRD, Malvern Zetasizer for particle size, ζ-potential, TEM, and SEM. Further, the preparation was investigated for % drug release, flux determination, antioxidant, and antimicrobial activity. The formulation stability was tested for 90 days and also evaluated formulation stability in fetal bovine serum to inspect the modification in physicochemical characteristics. NPs size was determined at 85 nm, PDI, and ζ-potential was recorded at 0.318, and 0.7 ± 0.4 mV. The % CIP and NAR entrapment efficiency and % loading were incurred as 91 ± 1.9, and 89.5 ± 1.2; 11.5 ± 0.6, and 10.8 ± 0.5%, respectively. The drug release erupted in the beginning phase followed by sustained and prolonged release for 48 h. The analytical experiments by DSC ensured the noninteracting and safe use of excipients in combination. X-ray studies demonstrated the amorphous state of the drug in the formulation. The insignificant alteration of formulation characteristics in FBS suggested stable and robust preparation. Storage stability of the developed formulation ensured consistent and uniform stability for three months. The DPPH assays demonstrated that NAR had good antioxidant capacity and supported improving antimicrobial activity of CIP. The hemolytic test suggested the developed formulation was compatible and caused insignificant RBC destruction. The in-house built formulation CIP + NAR-CM-CS/AG-NPs significantly improved the antimicrobial activity compared to CIP alone, offering a novel choice in antimicrobial application.

Defying the odds: Determinants of the antimicrobial response of Salmonella Typhi and their interplay

Salmonella Typhi, the invasive serovar of S. enterica subspecies enterica, causes typhoid fever in healthy human hosts. The emergence of antibiotic-resistant strains has consistently challenged the successful treatment of typhoid fever with conventional antibiotics. Antimicrobial resistance (AMR) in Salmonella is acquired either by mutations in the genomic DNA or by acquiring extrachromosomal DNA via horizontal gene transfer. In addition, Salmonella can form a subpopulation of antibiotic persistent (AP) cells that can survive at high concentrations of antibiotics. These have reduced the effectiveness of the first and second lines of antibiotics used to treat Salmonella infection. The recurrent and chronic carriage of S. Typhi in human hosts further complicates the treatment process, as a remarkable shift in the immune response from pro-inflammatory Th1 to anti-inflammatory Th2 is observed. Recent studies have also highlighted the overlap between AP, persistent infection (PI) and AMR. These incidents have revealed several areas of research. In this review, we have put forward a timeline for the evolution of antibiotic resistance in Salmonella and discussed the different mechanisms of the same availed by the pathogen at the genotypic and phenotypic levels. Further, we have presented a detailed discussion on Salmonella antibiotic persistence (AP), PI, the host and bacterial virulence factors that can influence PI, and how both AP and PI can lead to AMR.

Pharmacokinetics of oral ciprofloxacin in adult patients: A scoping review

AIMS

To map the literature on oral ciprofloxacin's pharmacokinetics and its implications for dose adjustments in specific populations.

METHODS

A scoping review was performed according to the Cochrane Collaboration and JBI and reported following the PRISMA-ScR. Systematic searches on electronic databases were conducted to integrate the current evidence on ciprofloxacin's pharmacokinetics. The quality of the included studies was assessed using ClinPK's checklist.

RESULTS

The search yielded 55 relevant studies. Within the traditional pharmacokinetics studies (n = 46), 86 profiles were examined (72 involving healthy patients and 14 with various clinical conditions). Oral ciprofloxacin's pharmacokinetics were influenced by covariates such as drug interactions (ferrous ions, calcium carbonate, diclofenac and itraconazole), food interactions (calcium-rich foods), elderly populations and renal impairment. Notably, variability in pharmacokinetic parameters existed among subjects, regardless of their health status, underscoring the need for comprehensive population descriptions. Population pharmacokinetic studies (n = 9) identified significant covariates for hospitalized patients, such as creatinine clearance, plasma bicarbonate, estimated glomerular filtration rate, renal replacement therapy, age, sex, total bilirubin, fat-free mass, dietary factors in renal disease, rifampicin for clearance models and body weight for volume of distribution models. Most pharmacokinetic/pharmacodynamic assessments concluded that 1200 mg/day provides a high probability of target attainment for bacteria with minimum inhibitory concentration <0.5 mg L-1 , aiming for an area under the curve for 24 h/minimum inhibitory concentration >125 h.

CONCLUSIONS

This study offers a comprehensive overview regarding oral ciprofloxacin's pharmacokinetics across various health conditions. It highlights the complexities of ciprofloxacin's pharmacokinetics, emphasizing the importance of considering multiple factors in dose adjustments.

A bacteriophage against Citrobacter braakii and its synergistic effect with antibiotics

A bacteriophage BD49 specific for Citrobacter braakii was screened out and purified by double-layer plate method. It consists of a polyhedral head of 93.1 ± 1.2 nm long and 72.9 ± 4.2 nm wide, tail fibers, collar, sheath and baseplate. The bacteriophage was identified by morphology observed with transmission electron microscope (TEM), whole genome sequencing carried out by Illumina next generation sequencing (NGS) technique, and gene annotation based on Clusters of Orthologous Groups of proteins (COG) database. It was identified primarily as a member of Caudovirales by morphology and further determined as Caudovirales, Myoviridae, and Citrobacter bacteriophage by alignment of its whole genome sequence with the NCBI database and establishment of phylogenetic tree. The bacteriophage showed good environmental suitability with optimal multiplicity of infection (MOI) of 0.01, proliferation time of 80 min, optimum living temperature of 30-40 °C, and living pH of 5-10. In addition, it exhibited synergistic effect with ciprofloxacin against C. braakii in antibacterial tests.

An Emerging Foodborne Pathogen Spotlight: A Bibliometric Analysis and Scholarly Review of Escherichia coli O157 Research

Foodborne infections pose a substantial global threat, causing an estimated 600 million illnesses and resulting in approximately 420,000 deaths annually. Among the diverse array of pathogens implicated in these infections, Escherichia coli (E. coli), specifically the O157 strain (E. coli O157), emerges as a prominent pathogen associated with severe outbreaks. This study employs a comprehensive bibliometric analysis and scholarly review focused on E. coli O157 research. The bibliometric analysis highlights the significant role played by the United States in the E. coli O157 research domain. Further exploration underscores the noteworthy contributions of the researcher Doyle MP, whose body of work, consisting of 84 documents and an impressive H-Index of 49, reflects their substantial impact in the field. Recent research trends indicate a discernible shift towards innovative detection methods, exemplified by the adoption of CRISPR-CAS and Loop-Mediated Isothermal Amplification. Moreover, high-throughput whole-genome sequencing techniques are gaining prominence for the expeditious analysis of pathogenic E. coli strains. Scientists are increasingly exploring antimicrobial agents, including phage therapy, to address the challenges posed by antibiotic-resistant E. coli strains, thereby addressing critical concerns related to multi-drug resistance. This comprehensive analysis provides vital insights into the dynamic landscape of E. coli O157 research. It serves as a valuable resource for researchers, policymakers, and healthcare professionals dedicated to mitigating E. coli O157 outbreaks and advancing global public health strategies.

Bioengineering the Antimicrobial Activity of Yeast by Recombinant Thanatin Production

The global spread of antibiotic resistance marks the end of the era of conventional antibiotics. Mankind desires new molecular tools to fight pathogenic bacteria. In this regard, the development of new antimicrobials based on antimicrobial peptides (AMPs) is again of particular interest. AMPs have various mechanisms of action on bacterial cells. Moreover, AMPs have been reported to be efficient in preclinical studies, demonstrating a low level of resistance formation. Thanatin is a small, beta-hairpin antimicrobial peptide with a bacterial-specific mode of action, predetermining its low cytotoxicity toward eukaryotic cells. This makes thanatin an exceptional candidate for new antibiotic development. Here, a microorganism was bioengineered to produce an antimicrobial agent, providing novel opportunities in antibiotic research through the directed creation of biocontrol agents. The constitutive heterologous production of recombinant thanatin (rThan) in the yeast Pichia pastoris endows the latter with antibacterial properties. Optimized expression and purification conditions enable a high production level, yielding up to 20 mg/L of rThan from the culture medium. rThan shows a wide spectrum of activity against pathogenic bacteria, similarly to its chemically synthesized analogue. The designed approach provides new avenues for AMP engineering and creating live biocontrol agents to fight antibiotic resistance.

Synergistic Effect of Thymol-Ciprofloxacin Combination on Planktonic Cells and Biofilm of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic bacteria causing severe and life-threatening infections in individuals with weakened immune systems. P. aeruginosa forms antibiotic-resistant biofilms, rendering it challenging to treat; hence, alternate therapies are required to eliminate it. Treatment of infections using a combination of drugs is gaining momentum to combat drug-resistant pathogens, including P. aeruginosa. This study explores the synergistic effects of Thymol in combination with Ciprofloxacin, Amikacin and Colistin against planktonic cells and biofilm of P. aeruginosa. Thymol in combination with Ciprofloxacin yields the fractional inhibitory concentration index values 0.156 and 0.375 in P. aeruginosa strains, GC14 and ATCC 9027, respectively, highlighting a robust synergistic effect on both the planktonic and biofilm of P. aeruginosa. The results showed that Thymol (512 μg/mL) and Ciprofloxacin (0.125 μg/mL) were the most effective combination with 95 and 93.5% total biofilm inhibition in GC14 and PA27, respectively, compared to the Thymol (512 μg/mL) and Ciprofloxacin (0.125 μg/mL) alone. Our findings suggest that the combinations of Thymol and Ciprofloxacin may be a potential therapeutic strategy to address the issue of infections caused by P. aeruginosa biofilms.

Secondary Metabolites from Fungi Microsphaeropsis spp.: Chemistry and Bioactivities

Microsphaeropsis, taxonomically classified within the kingdom fungi, phylum Ascomycota, subphylum Deuteromycotina, class Coelomycetes, order Sphaeropsidales, and family Sphaeropsidaceae, exhibit a ubiquitous distribution across various geographical regions. These fungi are known for their production of secondary metabolites, characterized by both structural novelty and potent biological activity. Consequently, they represent a significant reservoir for the advancement of novel pharmaceuticals. In this paper, a systematic review was present, marking the analysis of secondary metabolites synthesized by Microsphaeropsis reported between 1980 and 2023. A total of 112 compounds, comprising polyketones, macrolides, terpenoids, and nitrogen-containing compounds, were reported from Microsphaeropsis. Remarkably, among these compounds, 49 are novel discoveries, marking a significant contribution to the field. A concise summary of their diverse biological activities was provided, including antibacterial, antitumor, and antiviral properties and other bioactivities. This analysis stands as a valuable reference, poised to guide further investigations into the active natural products derived from Microsphaeropsis and their potential contributions to the development of medicinal resources.

Bacterial production of ciprofloxacin and potential usage as a radiotracer

Infectious diseases caused by bacteria that have become resistant to antibiotics have increased in prevalence, necessitating new methods for their diagnosis and treatment. The aim of this study was to compare the efficacy of synthetic ciprofloxacin to that of organic ciprofloxacin produced by cave microorganisms, as well as to evaluate the feasibility of using organic ciprofloxacin radiolabeled with technetium-99m as an imaging agent. Organic ciprofloxacin produced by cave bacteria isolated from sediment taken from the dark zone of Antalya's "Yark Sinkhole," (Turkey's 14th deepest cave), was purified using high-performance liquid chromatography. Purified organic ciprofloxacin and standard ciprofloxacin were radiolabeled with technetium-99m (99mTc), and their uptake by pathogenic microorganisms as well as potential as an imaging agent were examined. According to thin-layer radiochromatography, radiolabeling efficiencies were 98.99 ± 0.34 (n = 7) and 91.25 ± 1.84 (n = 7) for radiolabeled organic ciprofloxacin and standard ciprofloxacin respectively. The binding efficiency of radiolabeled organic ciprofloxacin at the 240th minute was higher compared with radiolabeled standard ciprofloxacin, especially with P.aeruginosa, MRSA, VRE and E.coli. The results demonstrate that radiolabeling with 99mTc does not alter the biological behavior of organic ciprofloxacin, and radiolabeled organic ciprofloxacin has potential as an imaging agent for the detection of bacterial infection. The original value of the study is the monitoring of the antibiofilm effects of untouched cave-derived organic antibiotics by radiolabeling with a radionuclide.

Identification and targeting of microbial putrescine acetylation in bloodstream infections

The growth of antimicrobial resistance (AMR) has highlighted an urgent need to identify bacterial pathogenic functions that may be targets for clinical intervention. Although severe bacterial infections profoundly alter host metabolism, prior studies have largely ignored alterations in microbial metabolism in this context. Performing metabolomics on patient and mouse plasma samples, we identify elevated levels of bacterially-derived N-acetylputrescine during gram-negative bloodstream infections (BSI), with higher levels associated with worse clinical outcomes. We discover that SpeG is the bacterial enzyme responsible for acetylating putrescine and show that blocking its activity reduces bacterial proliferation and slows pathogenesis. Reduction of SpeG activity enhances bacterial membrane permeability and results in increased intracellular accumulation of antibiotics, allowing us to overcome AMR of clinical isolates both in culture and in vivo. This study highlights how studying pathogen metabolism in the natural context of infection can reveal new therapeutic strategies for addressing challenging infections.

Changes in the Ultrastructure of Staphylococcus aureus Cells Make It Possible to Identify and Analyze the Injuring Effects of Ciprofloxacin, Polycationic Amphiphile and Their Hybrid

The purposeful development of synthetic antibacterial compounds requires an understanding of the relationship between effects of compounds and their chemical structure. This knowledge can be obtained by studying changes in bacteria ultrastructure under the action of antibacterial compounds of a certain chemical structure. Our study was aimed at examination of ultrastructural changes in S. aureus cells caused by polycationic amphiphile based on 1,4‒diazabicyclo[2.2.2]octane (DL412), ciprofloxacin and their hybrid (DL5Cip6); the samples were incubated for 15 and 45 min. DL412 first directly interacted with bacterial cell wall, damaging it, then penetrated into the cell and disrupted cytoplasm. Ciprofloxacin penetrated into cell without visually damaging the cell wall, but altered the cell membrane and cytoplasm, and inhibited the division of bacteria. The ultrastructural characteristics of S. aureus cells damaged by the hybrid clearly differed from those under ciprofloxacin or DL412 action. Signs associated with ciprofloxacin predominated in cell damage patterns from the hybrid. We studied the effect of ciprofloxacin, DL412 and their hybrid on S. aureus biofilm morphology using paraffin sections. Clear differences in compound effects on S. aureus biofilm (45 min incubation) were observed. The results obtained allow us to recommend this simple and cheap approach for the initial assessment of antibiofilm properties of synthesized compounds.

Genomic alterations involved in fluoroquinolone resistance development in Staphylococcus aureus

AIM

Fluoroquinolone (FQ) is a potent antibiotic class. However, resistance to this class emerges quickly which hinders its application. In this study, mechanisms leading to the emergence of multidrug-resistant (MDR) Staphylococcus aureus (S. aureus) strains under FQ exposure were investigated.

METHODOLOGY

S. aureus ATCC 29213 was serially exposed to ciprofloxacin (CIP), ofloxacin (OFL), or levofloxacin (LEV) at sub-minimum inhibitory concentrations (sub-MICs) for 12 days to obtain S. aureus -1 strains and antibiotic-free cultured for another 10 days to obtain S. aureus-2 strains. The whole genome (WGS) and target sequencing were applied to analyze genomic alterations; and RT-qPCR was used to access the expressions of efflux-related genes, alternative sigma factors, and genes involved in FQ resistance.

RESULTS

A strong and irreversible increase of MICs was observed in all applied FQs (32 to 128 times) in all S. aureus-1 and remained 16 to 32 times in all S. aureus-2. WGS indicated 10 noticeable mutations occurring in all FQ-exposed S. aureus including 2 insdel mutations in SACOL0573 and rimI; a synonymous mutation in hslO; and 7 missense mutations located in an untranslated region. GrlA, was found mutated (R570H) in all S. aureus-1 and -2. Genes encoding for efflux pumps and their regulator (norA, norB, norC, and mgrA); alternative sigma factors (sigB and sigS); acetyltransferase (rimI); methicillin resistance (fmtB); and hypothetical protein BJI72_0645 were overexpressed in FQ-exposed strains.

CONCLUSION

The emergence of MDR S. aureus was associated with the mutations in the FQ-target sequences and the overexpression of efflux pump systems and their regulators.

Bacteriophages: The promising therapeutic approach for enhancing ciprofloxacin efficacy against bacterial infection

BACKGROUND

The emergence of ciprofloxacin-resistant bacteria is a serious challenge worldwide, bringing the need to find new approaches to manage this bacterium. Bacteriophages (phages) have been shown inhibitory effects against ciprofloxacin-resistance bacteria; thus, ciprofloxacin resistance or tolerance may not affect the phage's infection ability. Additionally, researchers used phage-ciprofloxacin combination therapy for the inhibition of multidrug-resistant bacteria.

RESULTS

The sublethal concentrations of ciprofloxacin could lead to an increase in progeny production. Antibiotic treatments could enhance the release of progeny phages by shortening the lytic cycle and latent period. Thus, sublethal concentrations of antibiotics combined with phages can be used for the management of bacterial infections with high antibiotic resistance. In addition, combination therapy exerts various selection pressures that can mutually decrease phage and antibiotic resistance. Moreover, phage ciprofloxacin could significantly reduce bacterial counts in the biofilm community. Immediate usage of phages after the attachment of bacteria to the surface of the flow cells, before the development of micro-colonies, could lead to the best effect of phage therapy against bacterial biofilm. Noteworthy, phage should be used before antibiotics usage because this condition may have allowed phage replication to occur first before ciprofloxacin interrupted the bacterial DNA replication process, thereby interfering with the activity of the phages. Furthermore, the phage-ciprofloxacin combination showed a promising result for the management of Pseudomonas aeruginosa infections in mouse models. Nevertheless, low data are existing about the interaction between phages and ciprofloxacin in combination therapies, especially regarding the emergence of phage-resistant mutants. Additionally, there is a challenging and important question of how the combined ciprofloxacin with phages can increase antibacterial functions. Therefore, more examinations are required to support the clinical usage of phage-ciprofloxacin combination therapy.

The Effects of Antiperspirant Aluminum Chlorohydrate on the Development of Antibiotic Resistance in Staphylococcus epidermidis

This study investigates the effects of the antiperspirant aluminum chlorohydrate on the development of antibiotic resistance in commensal Staphylococcus epidermidis isolates. The isolates were exposed to aluminum chlorohydrate for 30 days. The bacteria that developed resistance to oxacillin and ciprofloxacin were isolated, and the expression levels of some antibiotic resistance genes were determined using quantitative reverse transcriptase PCR. Before and after exposure, the minimum inhibitory concentration (MIC) values of the bacteria were determined using the microdilution method. A time-dependent increase was observed in the number of bacteria that developed resistance and increased MIC values. Consistent with the ciprofloxacin resistance observed after exposure, an increase in norA, norB/C, gyrA, gyrB, parC, and parE gene expression was observed. In addition to aluminum chlorohydrate exposure, oxacillin resistance was observed in all test bacteria in the group only subcultured in the medium, suggesting that phenotypic resistance cannot be correlated with chemical exposure in light of these data. The increase in mecA gene expression in selected test bacteria that acquired resistance to oxacillin after exposure compared with control groups suggests that the observed resistance may have been related to aluminum chlorohydrate exposure. To our knowledge, this is the first time in the literature that the effects of aluminum chlorohydrate as an antiperspirant on the development of antibiotic resistance in Staphylococcus epidermidis have been reported.

Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus Associated with Hospitalized Newborn Infants

Multidrug resistance (MDR) is a significant challenge in healthcare management, and addressing it requires a comprehensive approach. In this study, we employed a combination of phenotypic and genotypic approaches, along with whole genome sequencing (WGS) to investigate five hospital-associated MDR methicillin-resistant Staphylococcus aureus (MRSA) strains that were isolated from newborn infants. Our analysis revealed the following for the MDR-MRSA strains: SauR31 was resistant to three antimicrobial classes; SauR12, SauR91 and SauR110 were resistant to four antimicrobial classes; and SauR23 exhibited resistance to seven classes. All the MDR-MRSA strains were capable of producing slime and biofilms, harbored SCCmec type IV, and belonged to different spa types (t022, t032, and t548), with varying profiles for microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) and virulence genes. The WGS data for the MDR SauR23 and SauR91 strains revealed that most of the antimicrobial resistance genes were present in the chromosomes, including blaZ, mecA, norA, lmrS, and sdrM, with only the ermC gene found in a small (<3 kb) plasmid. The presence of MDR-MRSA strains among neonates raises public concern, hence implementation of multifaceted interventions is recommended to address this issue. In addition, metadata is needed to improve the investigation of antimicrobial resistance genes in MDR isolates.

Evaluation of Neisseria gonorrhoeae Isolates Susceptibility to Antibiotics in Zhejiang Province Since 2007

Objective

This study aimed to assess the drug susceptibility of clinical isolates of Neisseria gonorrhoeae to spectinomycin, ceftriaxone and azithromycin. Moreover, the temporal trends in the minimum inhibitory concentration (MIC) of five antibiotics from Zhejiang, China, are also in the scope of this study.

Methods

A total of 1710 gonococcal clinical strains were collected between 2007 and 2021 from health-care institutions in Zhejiang. The MICs of ceftriaxone, azithromycin, spectinomycin, penicillin and ciprofloxacin were assessed by agar dilution method on 1710 Neisseria gonorrhoeae isolates. Count data were expressed as strains and rates, and MICs distribution was elucidated using descriptive statistics.

Results

The total resistance rates of gonococci to azithromycin, spectinomycin, penicillin and ciprofloxacin in this study were 19.3%, 0.3%, 75.4% and 99.7%, respectively.

Conclusion

The in vitro results showed a high prevalence of resistance to ciprofloxacin and penicillin. Azithromycin resistance rate has exceeded 5%, suggested a high prevalence of resistance. Ceftriaxone and spectinomycin are suggested based on this study for the treatment of Neisseria gonorrhoeae in Zhejiang.