The burden of hospital acquired infections and antimicrobial resistance

Antimicrobial Resistance and Hospital- and Community-Associated Infections

Antimicrobial resistance (AMR) poses a significant global threat to human health, and was estimated to be associated with almost one million deaths in 2019 [...].

Photobleaching of Light-Activated Porphyrin-Functionalized Plastic Coupons for Potential Antimicrobial Applications

Developing greener alternatives for harmful conventional cleaning agents is an important focus for preventing negative impacts on both the environment and human health. One potential alternative of interest is photodynamic inactivation (PDI), where a photosensitizing molecule is used to generate singlet oxygen (1O2) and other reactive oxygen species (ROS). ROS, 1O2 in particular, are known to react with cellular membranes of bacteria, resulting in cellular death. Porphyrinoids are one of these known light sensitizing species. In this work, zinc(II) 5,10,15,20-tetrakis((N-4-[3-(trifluoromethyl)-3H-diazirin-3-yl]benzyl)-4-pyridyl)-21H,23H-porphine tetrabromide is covalently attached to polyethylene terephthalate (PET) via thermal activation of a diazirine to initiate a C-H insertion. With the porphyrin now covalently bonded to the PET, the functionalized PET was assessed at a range of light intensities on its ability to generate 1O2 and for antimicrobial activity against Escherichia coli; the results were found to be correlated. Because photobleaching and resultant loss of activity are one of the weaknesses of PDI, the material was further assessed for its ability to withstand various photobleaching conditions. The photobleaching conditions assessed were high intensity light in dry and underwater conditions and ambient light, along with a set of dark controls. Results indicate that after 2 weeks of high intensity irradiation, the material still mediates singlet oxygen generation, albeit less efficiently. This shows promise for the use of this approach as an alternative to conventional cleaning agents.

Inherent variation in surface roughness of Selective Laser Melting (SLM) printed titanium caused by build angle changes the mechanomicrobiocidal effectiveness of nanostructures

Additively manufactured titanium implant materials are rapidly advancing prosthetics and orthopaedic devices by making them more cost-effective and customisable. However, the surface finish of materials printed via Selective Laser Melting (SLM) currently limits their integration into the medical device field. Printing parameters, such as build angle inclination, can cause variations in the surface roughness of a part, often exceeding what is suitable for implant materials. Excessive roughness can promote microbial attachment and proliferation, potentially leading to implant rejection. Nanostructuring titanium has previously demonstrated success in mitigating bacteria and fungi via a mechanomicrobiocial mechanism on traditionally flat titanium and complex SLM-made parts but its effectiveness on the inherent roughness of three-dimensional (3D) printed titanium remains unexplored. This study examines the surface roughness of 3D-Ti at three build angles (0, 40 and 90 degrees), before and after nanostructuring. Surfaces were assessed against methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans, representative antimicrobial resistant pathogens. Results showed the nanostructures were more effective against MRSA, but microbial attachment increase with steeper angles, regardless of the presence of nanostructures. This study investigates how surface roughness of 3D printed titanium substrates impacts bacterial and fungal adhesion and the resulting nanomorphology of the surface post-hydrothermal modification.

Novel silver(I) complexes with fenamates: Insights into synthesis, spectral characterization, and bioactivity

Six new Ag(I) ions complexes with N-phenylanthranilic, mefenamic, and niflumic acids have been synthesized. Three of them are binary complexes with the [Ag(L)] formula (where L represents N-phenylanthranilate (nfa), mefenamate (mfa), or niflumate (nif) ions), and the other three complexes are ternary with the formula [Ag(L)(phen)2]⋅nH2O (where phen - 1,10-phenanthroline). The complexes were characterized by elemental analysis, differential scanning calorimetry (DSC), X-ray fluorescence, powder X-ray diffraction, and single-crystal X-ray structure analysis. Additionally, techniques such as ESI-MS spectrometry, 1H NMR, UV-Vis, and FTIR spectroscopy were employed. The X-ray crystallography showed that in the solid [Ag(nif)] complex, the cation showed an unusual structure with coordination number 5, i.e. AgO3NC. The silver cation interacts with three niflumate anions, forming a two-dimensional coordination polymer. Complexes have potential antibacterial efficacy with varied minimum inhibitory concentration values (MIC) between 45.96 and 800 μM against multidrug-resistant Pseudomonas aeruginosa. Antibacterial combination therapy of Ag(I) complexes with chloramphenicol (CHL) and kanamycin (KAN) showed a very strong synergistic impact against P. aeruginosa with no cytotoxic effect on normal human fibroblasts. Complexes [Ag(nif)] and [Ag(nfa)] inhibit protein denaturation, bind to BSA via static quenching (kq = 0.65-1.08 × 1013 M-1 s-1). Furthermore, the formation of these complexes enhances the penetration of the drug across human membrane monolayers, which could improve bioavailability and therapeutic potential. The [Ag(nif)] complex demonstrates significant potential for topical dermal application due to its antimicrobial and anti-inflammatory properties. Notably, among all complexes evaluated, it displays the lowest BA/AB ratio (5.41), facilitating the most efficient transdermal permeation.

Editorial for the Special Issue "Healthcare-Associated Infections and Antimicrobial Therapy"

Hospital-acquired infections occur frequently among hospitalized patients and are associated with a significant increase in morbidity and mortality [...].

Clonal Dissemination of NDM-Producing Proteus mirabilis in a Teaching Hospital in Sousse, Tunisia

Proteus mirabilis (P. mirabilis) is an opportunistic pathogen involved in urinary tract infections as well as various nosocomial infections. Emerging resistances to beta-lactams in this species complicates potential treatment since it is intrinsically resistant to colistin. Eleven isolates of carbapenem-non-susceptible P. mirabilis were identified in Sousse Hospital, Tunisia, from January 2018 to December 2022. MICs were determined and isolates were sequenced to determine their resistomes, sequence types, virulence factors, and their clonal relationships. Susceptibility testing showed that all isolates were resistant to carbapenems, aminoglycosides, fluoroquinolones, chloramphenicol, and the trimethoprim/sulfamethoxazole combination. They remained susceptible to the aztreonam/avibactam combination. All isolates produced NDM-1 carbapenemase and ArmA 16S rRNA methylase. In addition, one isolate co-produced the blaVEB-6 gene. All isolates belonged to ST135, and phylogenetic analysis revealed that they were closely related. This study described the first outbreak of NDM-1-producing P. mirabilis in Tunisia.

Prevalence, antimicrobial resistance profiles, and determinants of Acinetobacter baumannii and Pseudomonas aeruginosa isolates among nosocomial infection--suspected patients in the northwestern region of Ethiopia

BACKGROUND

Pseudomonas aeruginosa and Acinetobacter baumannii are common causes of nosocomial infections. Furthermore, antimicrobial resistance is frequently observed in these pathogens, posing significant challenges to treatment.

OBJECTIVE

This study aimed to determine the prevalence, antimicrobial resistance profiles, and determinants of A baumannii and P aeruginosa isolates among nosocomial infection--suspected patients at Debre Markos Comprehensive Specialized Hospital.

METHODS

An institutional-based cross-sectional study was conducted from March 01, 2021 to May 30, 2021. A consecutive convenient sampling technique was applied to select 200 nosocomial infection--suspected patients. Clinical samples were collected and inoculated on MacConkey agar, blood agar, and Tryptic Soy broth. Testing for antibiotic susceptibility was done on Mueller Hinton agar.

RESULTS

The overall prevalence of A baumannii and P aeruginosa isolates among nosocomial infection--suspected patients was 11.5%. All isolates of P aeruginosa and A baumannii were 100% resistant to cefepime and piperacillin. Prolonged hospitalization and antibiotics use were significant determinants of P aeruginosa and A baumannii--induced nosocomial infection (adjusted odds ratio: 5.691, 95% CI: 1.069-7.296, P<.050 and adjusted odds ratio: 4.199, 95% CI: 0.997-6.675, P<.042, respectively).

CONCLUSIONS

The prevalence of A baumannii and P aeruginosa isolates was high in the study area. Therefore, there should be serious attention to control the spread of drug-resistant nosocomial infections in the study area.

Observed Prevalence and Characterization of Fluoroquinolone-Resistant and Multidrug-Resistant Bacteria in Loggerhead Sea Turtles (Caretta caretta) from the Adriatic Sea

Background/Objectives: Antimicrobial resistance (AMR) is a major global health concern with profound implications for human, animal, and environmental health. Marine ecosystems are emerging as reservoirs of resistant bacteria due to contamination from anthropogenic activities. This study aimed to investigate fluoroquinolone-resistant and multidrug-resistant bacteria in loggerhead sea turtles (Caretta caretta). Methods: Cloacal swabs were collected from 28 loggerhead sea turtles at a rescue center in southern Italy. Swabs were cultured in nutrient media supplemented with enrofloxacin. Bacterial isolates underwent identification by MALDI-TOF, antimicrobial susceptibility testing, and assessment for multidrug resistance. Conjugation experiments evaluated the transferability of enrofloxacin resistance. Results: Thirty-six enrofloxacin-resistant bacterial strains were isolated from 22 turtles. The identified species included Vagococcus fluvialis (13 strains), Citrobacter freundii (5), Escherichia coli (6), and Pseudomonas mendocina (4). Thirty-five isolates exhibited multidrug resistance, with resistance to critically important antibiotics such as imipenem observed in C. freundii and Enterobacter faecium. Conjugation experiments showed no transfer of resistance genes. Conclusions: The study highlights the prevalence of fluoroquinolone-resistant and multidrug-resistant bacteria in C. caretta, implicating marine environments as reservoirs of AMR. The findings underscore the need for stricter regulation of antimicrobial use and monitoring of resistance dissemination in marine ecosystems. These results contribute to understanding AMR dynamics within the One Health framework, emphasizing the interconnectedness of environmental, animal, and human health.

Synthesis, Antimicrobial Activities, and Model of Action of Indolyl Derivatives Containing Amino-Guanidinium Moieties

The objectives of the study were to design, synthesize, and evaluate the antibacterial activity of a series of novel aminoguanidine-indole derivatives. Thirty-seven new compounds were effectively synthesized through nucleophilic substitution reaction and guanidinylation reaction. Chemical structures of all the desired compounds were identified by NMR and HR-MS spectroscopy. Most of the synthesized compounds showed significant antibacterial activity against ESKAPE pathogens and clinical resistant Klebsiella pneumoniae (K. pneumoniae) isolates. K. pneumoniae is an important opportunistic pathogen that often threatens the health of immunocompromised people such as the elderly, children, and ICU patients. The most active compound 4P showed rapid bactericidal activity against resistant K. pneumoniae 2108 with MIC and MBC values that were 4 and 8 µg/mL, respectively. The hemolytic activity of 4P was low, with an HC50 value of 123.6 µg/mL. Compound 4P induced the depolarization of the bacterial membrane and disrupted bacterial membrane integrity and was not prone to antibiotic resistance. The dihydrofolate reductase (DHFR) activity was also notably inhibited by 4P in vitro. Molecular docking revealed that the aminoguanidine moiety and indole structure of 4P played an important role in binding to the target site of the K. pneumoniae dihydrofolate reductase (DHFR) receptor. In the mouse pneumonia model caused by K. pneumoniae, 4P improved the survival rate of mice, reduced bacterial loads, and alleviated tissues' pathological injuries at a dosage of 4 mg/kg. Therefore, compound 4P may be a promising lead compound or drug candidate for antibacterial purposes against K. pneumoniae.

Comprehensive analysis of antimicrobial resistance dynamics among broiler and duck intensive production systems

Antimicrobial resistance (AMR) is a global health challenge requiring cross-sector action, with research largely focused on chickens, leaving ducks underexplored. This study examines AMR dynamics in Ross 308 broilers and Cherry Valley ducks over 15 months and 15 stocking periods under consistent rearing conditions. A total of 96 pooled samples were collected: 50 from broiler farms (26 biological, 24 environmental) and 46 from duck farms (24 biological, 22 environmental). Using next-generation shotgun sequencing, 3,665 distinct AMR types were identified: 1,918 in broilers and 1,747 in ducks. Host-specific AMRs comprised 25.3% in broilers and 18% in ducks, while 56.7% were shared. AMR diversity declined across production phases, with broilers losing 641 types and ducks losing 308, yet AMR frequencies increased significantly by the finisher phase (p < 0.0001). Based on in silico data, prophylactic antibiotic use significantly reduced the prevalence of multidrug-resistant bacteria in both poultry species (p < 0.05). Hospital-acquired infection-associated AMRs were higher in broilers than in ducks at the start of production but declined significantly by the end of the rearing period (p < 0.0001). Above-average resistance markers accounted for approximately 10% of all detected resistance determinants. Tetracycline and phenicol resistances emerged as the most prevalent. 13 high-resistance carrier (HRC) species were shared between both hosts. Broiler-specific HRCs exhibited significantly higher abundances (relative frequency: 0.08) than duck-specific HRCs (relative frequency: 0.003, p = 0.035). The grower phase emerged as a critical intervention point. In farm environments 15 broiler-specific and 9 duck-specific biomarker species were identified, each strongly correlated with poultry-core HRCs (correlation coefficient > 0.7). Broiler exhibited higher abundances of key resistance genes, with tetracycline resistance predominantly associated with Bacteroides coprosuis, Pasteurella multocida, and Acinetobacter baumannii. Despite its limitations, this research provides key insights into AMR trends in two major poultry types, guiding targeted interventions and sustainable management strategies.

Graveyard effects of antimicrobial nanostructured titanium over prolonged exposure to drug resistant bacteria and fungi

Innovations in nanostructured surfaces have found a practical place in the medical area with use in implant materials for post-operative infection prevention. These textured surfaces should be dual purpose: (1) bactericidal on contact and (2) resistant to biofilm formation over prolonged periods. Here, hydrothermally etched titanium surfaces were tested against two highly antimicrobial resistant microbial species, methicillin-resistant Staphylococcus aureus and Candida albicans. Two surface types - unmodified titanium and nanostructured titanium - were incubated in a suspension of each microbial strain for 1 day and 7 days. Surface topography and cross-sectional information of the microbial cells adhered to the surfaces, along with biomass volume and live/dead rate, showed that while nanostructured titanium was able to kill microbes after 1 day of exposure, after 7 days, the rate of death becomes negligible when compared to the unmodified titanium. This suggests that as biofilms mature on a nanostructured surface, the cells that have lysed conceal the nanostructures and prime the surface for planktonic cells to adhere, decreasing the possibility of structure-induced lysis. Synchrotron macro-attenuated total reflection Fourier transform infrared (macro ATR-FTIR) micro-spectroscopy was used to elucidate the biochemical changes occurring following exposure to differing surface texture and incubation duration, providing further understanding into the effects of surface morphology on the biochemical molecules (lipids, proteins and polysaccharides) in an evolving and growing microbial colony.

Improvement in antibacterial use in intensive care units from Argentina: A quality improvement collaborative process evaluation using Normalization Process Theory

BACKGROUND

Healthcare-associated infections and antibiotic resistance worsen globally. Antibiotic stewardship programs (ASP) aim to optimise infection treatment and curb resistance, yet implementation hurdles persist. This study examined ASP challenges in ICUs.

METHODS

This study employed a qualitative methodological design to evaluate the implementation process of an antibiotic stewardship program (ASP) in eight intensive care units (ICUs) across Argentina. Thirty-four semi-structured interviews with healthcare workers (HCWs) were conducted. Interviews were analysed guided by Normalisation Process Theory, examining coherence, cognitive participation, collective action, and reflexive monitoring constructs.

RESULTS

Key challenges included insufficient human resources, lack of institutional support, and resistance to change, particularly among staff not initially involved in the study. Despite these challenges, the program saw partial success in improving ICU practices, particularly in antibiotic use and communication across departments. The main strategy implemented in this quality improvement collaborative was the use of improvement cycles, which served as the central component for driving change. However, participation in improvement cycles was inconsistent, and sustainability post-intervention remains uncertain due to workload pressures and the need for continuous education. Concerns about workload and communication barriers persisted. Many participants did not perceive training as a separate component, which led to low engagement. Resistance to change became evident during modifications to clinical guidelines. The intervention had a positive impact on various processes, including communication and record keeping.

CONCLUSION

This study underscores the persistent challenges in implementing ASPs in healthcare, emphasising the need for enhanced collaboration, workforce capacity building, and evidence-based practices to overcome barriers and optimize antimicrobial use to improve patient outcomes.

Tracheal tube infections in critical care: A narrative review of influencing factors, microbial agents, and mitigation strategies in intensive care unit settings

Tracheal tube infections pose significant challenges in the management of mechanically ventilated patients in intensive care units. These infections contribute to prolonged intensive care unit stays, increased healthcare costs, the spread of antibiotic resistance, and poor patient outcomes. This study aims to elucidate the complex relationship between environmental factors, hospital practices, and the incidence of tracheal tube infections. Our comprehensive review explores the impact of factors such as air quality, water sources, equipment contamination, ventilation strategies, infection control protocols, and microbial reservoirs within hospital settings on tracheal tube infection rates. Additionally, it investigates global variations in tracheal tube infection prevalence, which are influenced by differences in healthcare infrastructure, infection control adherence, antibiotic resistance profiles, and patient demographics. Our findings highlight the importance of targeted interventions and collaborative approaches to reduce the burden of tracheal tube infections and improve patient care in intensive care units. By fully understanding the interplay between environmental conditions and hospital practices, effective prevention and management strategies can be developed to reduce the impact of tracheal tube infections on patient outcomes and healthcare resources, ultimately enhancing the quality of care in critical care settings.

Delayed reconstruction of the combat-related mandibular defects with non-vascularized iliac crest grafts: Defining the optimal conditions for a positive outcome in the retrospective study

BACKGROUND

Reconstruction of mandibular defects caused by combat injuries is challenging for clinicians due to soft tissue defects and high complication risk. This study evaluated the outcomes of mandibular continuous defects reconstruction with non-vascularized iliac crest graft (NVICG) in patients with combat injuries.

MATERIAL AND METHODS

Patients with continuous mandibular defects acquired by high-velocity agents, who received NVICG reconstruction with or without microvascular-free soft tissue or regional flaps, were included in the study. The outcome variable was graft loss due to postoperative complications or full (more than 90 %) resorption. The primary predictor variable was soft tissue defect in the recipient area. The secondary predictor variable was the length of the defect. Variables related to patients, defect site, surgery, and other complications were also evaluated. Statistical analysis was performed with the usage of independent sample t-test, Pearson's chi-squared and Fisher's exact tests with a significance level of P < 0.05 RESULTS: The study included 24 patients with 27 mandibular defects. Overall, the general success rate of reconstructions was 59.3 %. Soft tissue defects were significantly associated with graft failure and other complications (p < 0.05), which were mostly related to soft tissue defects. The graft success rate was only 14.3 % even in minor soft tissue defects. In turn, in reconstructions with sufficient soft tissue coverage, the graft survived in 75.0 % of the cases. In addition, patients with more delayed reconstruction had significantly fewer graft failures than those with earlier surgery (p < 0.05). No associations were found between defect size and complications.

CONCLUSION

The sufficient soft tissue coverage is essential in the reconstruction of mandibular defects caused by combat injuries. Also, minor soft tissue defects should be covered with soft tissue flaps to avoid complications and graft loss in these specific injuries. Even large defects can be reconstructed with NIVICG if the soft tissue coverage is sufficient.

Effect of amikacin-humic acid combination on Acinetobacter baumannii biofilm: an in vitro and in silico study

Aim: Acinetobacter baumannii (AB) is a clinically important bacterial pathogen responsible for nosocomial infections. The biofilm-forming capability of these pathogens reduces the antibiotic penetration and its efficacy, thereby complicating the treatment. The current work aims to isolate the most potent biofilm-forming Acinetobacter species from clinical isolates of the patient samples and to evaluate the efficacy of the amikacin-humic acid combination against it.Methods: The combination effect of Amikacin-Humic (AMK-HUM) acid against the highest biofilm-producing A. baumannii SLMK001 was studied via in-vitro (microscopic analysis) and in-silico (Network Pharmacology) analysis.Results: The amikacin-humic acid combination significantly inhibited both the biofilm formation and cell viability of A. baumannii SLMK001. The images observed via Scanning Electron Microscope (SEM) showed a significant decrease in the biofilm matrix. Confocal Laser Scanning Microscope (CLSM) confirmed a reduction of the Z value of its three-dimensional structure. Further, the Network Pharmacology approach supported these experimental findings by identifying the key targets of the amikacin-humic acid combination against the biofilm pathways of A. baumannii.Conclusion: The in-vitro results aligned with the in-silico findings, indicating that the AMK-HUM combination is a promising treatment that significantly activates the key proteins against A. baumannii biofilm formation and pathogenesis.

Perspectives on the Regional Strategy for Implementation of National Action Plans on Antimicrobial Resistance in the WHO African Region

Background: The WHO Regional Office for Africa developed a Member States (MS)-endorsed regional strategy to fast-track the implementation of MS' national action plans (NAP) on Antimicrobial resistance (AMR). This study explored the perspectives of AMR's national focal points in MS on the implementation of the priority interventions of the regional strategy in their countries. Methods: An online survey consisting of ratings and discussions covering the implementation of the six priority interventions was conducted. Sums of the scores per priority intervention were obtained, and their percentage to the total possible scores were calculated to categorize the implementation as inadequate (0-25%), basic (26-50%), intermediate (51-75%), or advanced (76-100%). Results: Thirty-six of the forty-seven national AMR focal points responded to the survey between 12 November 2023 and 8 January 2024. The implementations were rated as 37-62% (basic-to-intermediate), with the multisectoral coordination and collaboration committee receiving the highest overall rating (62%, 421/684), while the promotion of sustainable investment for the NAP on AMR received the least overall rating (37%, 257/700). The focal points mainly recommended awareness campaigns, capacity building, and regulations and guidelines to improve the implementation of the AMR strategy. Conclusions: The survey revealed a need to enhance awareness campaigns, support the establishment and functioning of AMR evaluation and monitoring systems, and build the capacity of AMR staff with cost-benefit analysis and budgeting skills. It also showed the necessity to improve awareness and conduct education on AMR, streamline evidence generation through One Health Surveillance systems, integrate initiatives to reduce hospital-acquired infections in the antimicrobial stewardship programs, and enhance regulations and guidelines to optimize the use of antimicrobials.

A clinical trial evaluation of handwashing products and educational resources to improve hand hygiene in paediatric patients and school children

Introduction

It is widely acknowledged that good hand hygiene (HH) is an important non-pharmaceutical method for reducing the transmission of infectious diseases. Children are at high risk of infection due to their immature immune systems. Hospital transmitted infections are a cause for concern worldwide, with poor HH suggested to be responsible for up to 20% of cases. Patients, in particular paediatric patients, are often overlooked when it comes to the promotion of hand hygiene compliance (HHC) in hospitals. This report describes the clinical evaluation of the 'Soaper Stars'; a collection of child-friendly HH products with linked educational resource, developed using the COM-B approach to behaviour change, and designed to encourage correct HH in paediatric patients and in schools.

Method

The Soaper Star products were distributed on paediatric wards in five UK hospitals, and the use of the products around mealtimes was evaluated. Workshops teaching the 'why when and how' of handwashing were run in four UK primary schools with pre and post evaluations conducted to establish impact on knowledge. Over 300 children were involved.

Results

The Soaper Stars products stimulated a 38% increase in HHC compared to when only hospital-issued products were available, and verbal feedback from families indicated that having the Soaper Star products encouraged improved HHC by all visitors, not just the patient. Workshops in four schools (283 pupils) showed an increase in knowledge around the transmission of infection and the need for good HH that was sustained for at least 4 weeks.

Conclusion

The results of this study demonstrate that providing children with the age-appropriate knowledge about why HH is necessary, and the child-friendly means to maintain their HH, will lead to greater HHC, not just by individual children, but also their families.

Modeling the transmission of antibiotic-resistant Enterobacterales in the community: A systematic review

BACKGROUND

Antibiotic-resistant Enterobacterales (ARE) are a public health threat worldwide. Dissemination of these opportunistic pathogens has been largely studied in hospitals. Despite high prevalence of asymptomatic colonization in the community in some regions of the world, less is known about ARE acquisition and spread in this setting. As explaining the community ARE dynamics has not been straightforward, mathematical models can be key to explore underlying phenomena and further evaluate the impact of interventions to curb ARE circulation outside of hospitals.

METHODS

We conducted a systematic review of mathematical modeling studies focusing on the transmission of AR-E in the community, excluding models only specific to hospitals. We extracted model features (population, setting), formalism (compartmental, individual-based), biological hypotheses (transmission, infection, antibiotic impact, resistant strain specificities) and main findings. We discussed additional mechanisms to be considered, open scientific questions, and most pressing data needs.

RESULTS

We identified 18 modeling studies focusing on the human transmission of ARE in the community (n=11) or in both community and hospital (n=7). Models aimed at (i) understanding mechanisms driving resistance dynamics; (ii) identifying and quantifying transmission routes; or (iii) evaluating public health interventions to reduce resistance. To overcome the difficulty of reproducing observed ARE dynamics in the community using the classical two-strains competition model, studies proposed to include mechanisms such as within-host strain competition or a strong host population structure. Studies inferring model parameters from longitudinal carriage data were mostly based on models considering the ARE strain only. They showed differences in ARE carriage duration depending on the acquisition mode: returning travelers have a significantly shorter carriage duration than discharged hospitalized patient or healthy individuals. Interestingly, predictions across models regarding the success of public health interventions to reduce ARE rates depended on pathogens, settings, and antibiotic resistance mechanisms. For E. coli, reducing person-to-person transmission in the community had a stronger effect than reducing antibiotic use in the community. For Klebsiella pneumoniae, reducing antibiotic use in hospitals was more efficient than reducing community use.

CONCLUSIONS

This study raises the limited number of modeling studies specifically addressing the transmission of ARE in the community. It highlights the need for model development and community-based data collection especially in low- and middle-income countries to better understand acquisition routes and their relative contribution to observed ARE levels. Such modeling will be critical to correctly design and evaluate public health interventions to control ARE transmission in the community and further reduce the associated infection burden.

Determinants of Healthcare-Associated Infections in King Abdulaziz Specialized Hospital in Taif, Saudi Arabia

BACKGROUND

Healthcare-associated infections (HAIs) represent a significant challenge in hospital settings, contributing to increased morbidity, mortality, and healthcare costs. This study aimed to estimate the prevalence and socio-demographic and clinical determinants of HAIs at the King Abdulaziz Specialized Hospital (KAASH) in Taif, Saudi Arabia.

METHODOLOGY

A hospital-based cross-sectional study was conducted from March 2023 to January 2024 targeting inpatients aged 18 and above in all units and wards. Data were collected using the National Healthcare Safety Network (NHSN) criteria for definitions of surveillance. A structured questionnaire gathered socio-demographic and clinical data from patients or next of kin if the patient was not fully oriented. Descriptive statistics were performed, and analytical methods used included Pearson chi-square test, Pearson correlation, independent t-test, and one-way analysis of variance.

RESULTS

Among 318 participants included in this study, the mean age of participants was 56.44 years, with a slight female predominance (n=164, 51.6%). Hypertension (n=162, 50.9%) and diabetes (n=126, 39.6%) were the most prevalent comorbidities. Pneumonia (n=60, 26.8%) and trauma (n=55, 17.4%) were the leading causes of admission. The two most common HAIs included catheter-associated urinary tract infections (CAUTI) (n=124, 39%) and central line-associated bloodstream infections (CLABSI) (n=74, 23.3%). The primary causative organisms were Klebsiella pneumoniae (n=96, 30.2%) and Acinetobacter baumannii (n=32, 10.1%). The most significant predictors of HAIs were as follows: For CLABSI, risk factors include having three or more comorbidities, fever above 37.8°C, chills or rigors, hypotension, and positive blood culture. For CAUTI, key predictors were urinary tract infection (UTI), positive urine culture, acute pain or swelling of the testes, suprapubic tenderness, visible hematuria, and leukocytosis. Significant predictors of bloodstream infections (BSI) include having a BSI, positive blood culture, chills or rigors, and hypotension. Fever and hypotension increased CLABSI and BSI risk but reduced the CAUTI risk.

CONCLUSION

The study highlights a significant burden of HAIs at the KAASH, with multiple predictors. The findings underscore the need for robust infection control measures and targeted interventions to reduce HAI incidence and improve patient outcomes.

Horizontal plasmid transfer promotes antibiotic resistance in selected bacteria in Chinese frog farms

The emergence and dissemination of antibiotic resistance genes (ARGs) in the ecosystem are global public health concerns. One Health emphasizes the interconnectivity between different habitats and seeks to optimize animal, human, and environmental health. However, information on the dissemination of antibiotic resistance genes (ARGs) within complex microbiomes in natural habitats is scarce. We investigated the prevalence of antibiotic resistant bacteria (ARB) and the spread of ARGs in intensive bullfrog (Rana catesbeiana) farms in the Shantou area of China. Antibiotic susceptibilities of 361 strains, combined with microbiome analyses, revealed Escherichia coli, Edwardsiella tarda, Citrobacter and Klebsiella sp. as prevalent multidrug resistant bacteria on these farms. Whole genome sequencing of 95 ARB identified 250 large plasmids that harbored a wide range of ARGs. Plasmid sequences and sediment metagenomes revealed an abundance of tetA, sul1, and aph(3″)-Ib ARGs. Notably, antibiotic resistance (against 15 antibiotics) highly correlated with plasmid-borne rather than chromosome-borne ARGs. Based on sequence similarities, most plasmids (62%) fell into 32 distinct groups, indicating a potential for horizontal plasmid transfer (HPT) within the frog farm microbiome. HPT was confirmed in inter- and intra-species conjugation experiments. Furthermore, identical mobile ARGs, flanked by mobile genetic elements (MGEs), were found in different locations on the same plasmid, or on different plasmids residing in the same or different hosts. Our results suggest a synergy between MGEs and HPT to facilitate ARGs dissemination in frog farms. Mining public databases retrieved similar plasmids from different bacterial species found in other environmental niches globally. Our findings underscore the importance of HPT in mediating the spread of ARGs in frog farms and other microbiomes of the ecosystem.

Metal Nanoparticle-Based Biosensors for the Early Diagnosis of Infectious Diseases Caused by ESKAPE Pathogens in the Fight against the Antimicrobial-Resistance Crisis

The species included in the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and the genus Enterobacter) have a high capacity to develop antimicrobial resistance (AMR), a health problem that is already among the leading causes of death and could kill 10 million people a year by 2050. The generation of new potentially therapeutic molecules has been insufficient to combat the AMR "crisis", and the World Health Organization (WHO) has stated that it will seek to promote the development of rapid diagnostic strategies. The physicochemical properties of metallic nanoparticles (MNPs) have made it possible to design biosensors capable of identifying low concentrations of ESKAPE bacteria in the short term; other systems identify antimicrobial susceptibility, and some have been designed with dual activity in situ (bacterial detection and antimicrobial activity), which suggests that, in the near future, multifunctional biosensors could exist based on MNPs capable of quickly identifying bacterial pathogens in clinical niches might become commercially available. This review focuses on the use of MNP-based systems for the rapid and accurate identification of clinically important bacterial pathogens, exhibiting the necessity for exhaustive research to achieve these objectives. This review focuses on the use of metal nanoparticle-based systems for the rapid and accurate identification of clinically important bacterial pathogens.

Fabrication of Ciprofloxacin-Loaded Sodium Alginate Nanobeads Coated with Thiol-Anchored Chitosan Using B-390 Encapsulator Following Optimization by DoE

Most infectious diseases of the gastrointestinal tract can easily be treated by exploiting the already available antibiotics with the change in administration approach and delivery system. Ciprofloxacin (CIP) is used as a drug of choice for many bacterial infections; however, long-term therapy and off-site drug accumulation lead to an increased risk of tendinitis and peripheral neuropathy. To overcome this issue, nanotechnology is being exploited to encapsulate antibiotics within polymeric structures, which not only facilitates dose maintenance at the infection site but also limits off-site side effects. Here, sodium alginate (SA) and thiol-anchored chitosan (TC) were used to encapsulate CIP via a calcium chloride (CaCl2) cross-linker. For this purpose, the B-390 encapsulator was employed in the preparation of nanobeads using a simple technique. The hydrogel-like sample was then freeze-dried, using trehalose or mannitol as a lyoprotectant, to obtain a fine dry powder. Design of Experiment (DoE) was utilized to optimize the nanobead production, in which the influence of different independent variables was studied for their outcome on the polydispersity index (PDI), particle size, zeta potential, and percentage encapsulation efficiency (% EE). In vitro dissolution studies were performed in simulated saliva fluid, simulated gastric fluid, and simulated intestinal fluid. Antibacterial and anti-inflammatory studies were also performed along with cytotoxicity profiling. By and large, the study presented positive outcomes, proving the advantage of using nanotechnology in fabricating new delivery approaches using already available antibiotics.

Engineered endolysin of Klebsiella pneumoniae phage is a potent and broad-spectrum bactericidal agent against "ESKAPEE" pathogens

The rise of antimicrobial resistance in ESKAPEE pathogens poses significant clinical challenges, especially in polymicrobial infections. Bacteriophage-derived endolysins offer promise in combating this crisis, but face practical hurdles. Our study focuses on engineering endolysins from a Klebsiella pneumoniae phage, fusing them with ApoE23 and COG133 peptides. We assessed the resulting chimeric proteins' bactericidal activity against ESKAPEE pathogens in vitro. ApoE23-Kp84B (CHU-1) reduced over 3 log units of CFU for A. baumannii, E. faecalis, K. pneumoniae within 1 h, while COG133-Kp84B (CHU-2) showed significant efficacy against S. aureus. COG133-L1-Kp84B, with a GS linker insertion in CHU-2, exhibited outstanding bactericidal activity against E. cloacae and P. aeruginosa. Scanning electron microscopy revealed alterations in bacterial morphology after treatment with engineered endolysins. Notably, CHU-1 demonstrated promising anti-biofilm and anti-persister cell activity against A. baumannii and E. faecalis but had limited efficacy in a bacteremia mouse model of their coinfection. Our findings advance the field of endolysin engineering, facilitating the customization of these proteins to target specific bacterial pathogens. This approach holds promise for the development of personalized therapies tailored to combat ESKAPEE infections effectively.

Bacterial Infections: Surveillance, Prevention and Control

Bacteria play a vital role in maintaining human health, but they may also be responsible for many different serious infections and diseases [...].

Aptamers: A Cutting-Edge Approach for Gram-Negative Bacterial Pathogen Identification

Early and accurate diagnoses of pathogenic microorganisms is essential to correctly identify diseases, treating infections, and tracking disease outbreaks associated with microbial infections, to develop precautionary measures that allow a fast and effective response in epidemics and pandemics, thus improving public health. Aptamers are a class of synthetic nucleic acid molecules with the potential to be used for medical purposes, since they can be directed towards any target molecule. Currently, the use of aptamers has increased because they are a useful tool in the detection of specific targets. We present a brief review of the use of aptamers to detect and identify bacteria or even some toxins with clinical importance. This work describes the advances in the technology of aptamers, with the purpose of providing knowledge to develop new aptamers for diagnoses and treatment of different diseases caused by infectious microorganisms.

Advancements in nanosensors for detecting pathogens in healthcare environments

ESKAPEE pathogens: where we can find them in hospital environments and how to detect them through nanotechnologies devices.