Antibiotic-resistant Bacteria Research Articles

Crouching bacteria, hidden tetA genes in natural waters: intracellular damage via double persulfate activation (UVA/Fe2+/PDS) effectively alleviates the spread of antibiotic resistance

In this study, we elucidated the chemical and biological inactivation mechanisms of peroxydisulfate (PDS) activated by UVA and Fe2+ (UVA/Fe2+/PDS) in wild-type antibiotic-resistant bacteria (ARB) isolated from a river in Inner Mongolia. Among the screened wild-type ARB, the relative abundance of unidentified Enterobacteriaceae, Stenotrophomonas, and Ralstonia was high. A ratio of 1:1 for Fe2+ and PDS under 18W·m-2 UVA radiation (sunny days) completely inactivated the environmental ARB isolates. In the macro view of the inactivation process, Fe2+ first activates PDS rapidly, and later the UVA energy accumulated starts to activate PDS; HO• then becomes the main active species at a rate-limiting step. From a micro perspective, damage to the cell wall, intracellular proteins, inactivation of antioxidant enzymes, and genetic material degradation are the inactivation series of events by UVA/Fe2+/PDS, contributing to the 97.8% inactivation of ARB at the initial stage. No regrowth of sublethal ARBs was observed. The transfer of tetracycline resistance genes from ARB to lab E. coli was evaluated by horizontal gene transfer (HGT), in which no HGT occurred when ARB was eliminated by UVA/Fe2+/PDS. Moreover, the sulfate and iron residuals in the effluents of treated water were lower than the drinking water standards. In summary, PDS, UVA, and Fe2+ activation effectively inactivated wild ARB with a low concentration of reagents, while inhibiting their regrowth and spread of resistance due to the contribution of intracellular inactivation pathways. Environmental ImplicationAntibiotic resistance bacteria (ARB) were isolated from the feces and river of Inner Mongolian Plateau, which indicated that the grassland system and surface water had been polluted by the antibiotic resistance. In our previous survey, most people living in remote pasture lands, are using surface water for drinking.Hence, we applied UVA/Fe2+/PDS to control the antibiotic resistance, which has great oxidative ability and lower input requires. ARB and antibiotic resistance genes (ARGs) were well eliminated, and the chemicals of effluent were under the drinking water requires. UVA/Fe2+/PDS is an environmental-friendly disinfection method, which effectively protect the ecological and human health.

Fate of fluoroquinolones associated with antimicrobial resistance in circular periurban agriculture

Animal antibiotic use contributes to antimicrobial resistance (AMR) in humans. While animal manure benefits soil fertility, it also acts as hotspot for antibiotic residues, antibiotic-resistant bacteria, and their genes. Amending soils with poultry litter is recognized as “magic” among horticulture farmers and it remains a common practice globally. However, this poses a risk especially in countries where prophylactic use of antibiotics is allowed. In Argentina, fluoroquinolones are used in this way besides being listed as essential medicines and classified as “watch” by the World Health Organization. Antibiotics selective pressure can favour AMR in the environment but the fate of antibiotic residues and AMR dissemination from these practices remains poorly understood. Our research addresses this gap with a biological model tracing fluoroquinolones from poultry to soil to lettuce and tracking anthropogenic AMR with the proposed biomarker genes sul1 and intI1. Fresh poultry litter was stored for six months before application in a horticulture field experiment. The experiment included control and manured plots where lettuce was cultivated till harvest. Enrofloxacin concentration was 7.3 μg/kg in fresh poultry litter, while its metabolite ciprofloxacin was 39.22 μg/kg after storage. Although no fluoroquinolones were detected in soils, lettuce from manured plots contained enrofloxacin and ciprofloxacin at 14.97 and 9.77 μg/kg, respectively, providing evidence of fluoroquinolone bioaccumulation in plants. Abundance of sul1 and intI1 in poultry litter was not affected by storage. Manured soils showed better soil quality than controls, but sul1 gene abundance was 1.6 times higher, reaching 7.61 Log sul1/g soil. A less sensitive, but significant effect was registered for intI1. These findings show that static storage is insufficient to stop the transmission of antibiotics and AMR biomarkers from poultry to horticulture. Amending soil with industrial poultry litter contributes to pollution with these emergent contaminants and risks human antibiotic exposure through fresh vegetables.

Culture-based and molecular investigation of antibiotic and metal resistance in a semi-arid agricultural soil repeatedly amended with urban sewage sludge

Unsustainable agricultural intensification and climate change effects have caused chronic soil depletion in most arid and semi-arid croplands. As such, the land application of urban sewage sludge (USS) has been regulated in several countries as an alternative soil conditioner with recycling benefits. However, the risks of multi-contamination have made its agricultural reuse debatable. Accordingly, this study explored the long-term the impact of repetitive USS applications with increasing rates (0, 40, 80, and 120 t ha-1 year-1) on a sandy soil properties. A special focus was on the spread of antibiotic-resistant bacteria, metal-resistant bacteria and corresponding resistance genes in soil (ARB, MRB, ARGs and MRGs, respectively). The outcomes showed a dose-dependent variation of different soil parameters including the increase of heavy metal content and total heterotrophic bacteria (THB) up to the highest sludge application rate. Besides, the two last sludge lots applied in fall 2019 and 2020 contained cultivable ARB for all addressed antibiotics at much higher counts than in corresponding treated soils. Interestingly, the average index of antibiotic resistance (ARB/THB) increased in the USS used in fall 2020 compared to 2019 (from 6.2% to 9.4%). This indicates that factors such as fluctuations in wastewater quality, treatments operations, and extensive antibiotic use following the outbreak of the COVID-19 pandemic in early 2020 could have caused this variation. The molecular assessment of bacterial resistance resulted in the identification of three ARGs (mefA, sul1 and sul2), one MRG (czcA) and one integron (intI1). This might have implications on resistance co-selection, which can pose a threat to human health via contaminated crops.

Combined impact of antibiotics and Cr(VI) on antibiotic resistance, ARGs, and growth of Bacillussp. SH-1: A functionl analysis from gene to protease

The simultaneous selection of antibiotic resistance genes (ARGs) induced by heavy metals and antibiotics has emerged as a growing environmental problem. This study investigated the combined effects of chromium (Cr(VI)) and antibiotics on the ARGs of Bacillus cereus SH-1. As Cr(VI) concentration increased, it triggered reactive oxygen species oxidative stress in SH-1, increased antioxidant enzyme activity, enhanced plasmid conjugative transfer, and reduced the efficiency of Cr(VI) removal by SH-1. Antibiotic resistance varied with increasing tetracycline and amoxicillin minimum inhibitory concentrations (MICs), whereas azithromycin and chloramphenicol MICs decreased with Cr(VI) induction. The overexpression of eight genes of the HAE-1 family of efflux pumps was detected using metagenomics and proteomics. Co-contamination with Cr(VI) and antibiotics has led to the emergence and spread of antibiotic-resistant bacteria. Therefore, resistance gene contamination resulting from Cr(VI)-polluted environments cannot be overlooked.

Microalgae-Assisted Treatment of Wastewater Originating from Varied Sources, Particularly in the Context of Heavy Metals and Antibiotic-Resistant Bacteria

The increasing prevalence of heavy metals and antibiotic-resistant bacteria in wastewater (WW) raises serious environmental and public health concerns. This study investigates the efficiency of the microalgal strain Chlorella vulgaris EV-465 in treating wastewater and evaluates the antibiotic resistance profile of bacterial strains obtained from WW samples. Chlorella vulgaris EV-465 was used to treat four types of wastewater—domestic, municipal, hospital, and industrial wastewater—through 21 days of incubation. The findings demonstrated pH stabilization and significant decreases in nutrients (total nitrogen—TN, total phosphorus—TP), biological oxygen demand (BOD), chemical oxygen demand (COD), heavy metal (HM) concentrations, and bacterial count. Copper (Cu) showed the highest reduction, decreasing by 80% in industrial wastewater within 14 days, while lead (Pb) proved more resistant to removal, with only a 50% decrease by day 21. Additionally, the algae decreased bacterial counts, lowering colony-forming units (Log CFU/mL) from 9.04 to 4.65 in municipal wastewater over the 21-day period. Antibiotic susceptibility tests for isolated bacterial strains revealed high levels of resistance, with seven out of nine bacterial strains exhibiting multidrug resistance. Notably, Enterococcus faecium (PBI08), Acinetobacter baumannii (YBH19), and Pseudomonas aeruginosa (NBH16) displayed resistance to all nine antibiotics tested. Among the tested antibiotics, Ciprofloxacin showed the highest efficacy, with 66% susceptibility of tested bacterial strains. Cluster and phylogenetic analyses showed that the majority of the isolated bacterial strains belonged to the genera Pseudomonas and Escherichia, highlighting their genetic diversity and varied resistance mechanisms.

Exploring the Antibacterial Properties and Chemical Profiles of Essential Oils from Syzygium aromaticum and Nigella sativa Against MDR Bacteria

For centuries, plants have been studied for their healing properties. Recently, the rise of antibiotic resistance in bacteria has prompted scientists to explore herbal remedies. Syzygium aromaticum, from the Myrtaceae family, has been utilized as a histological clearing agent. In contrast, Nigella sativa (black cumin), a member of the Ranunculaceae family, has long been utilized in traditional medicine dating back to ancient times. The current study investigates the chemical composition and antibacterial activity of essential oils from Syzygium aromaticum (clove) and Nigella sativa (black cumin) against multidrug-resistant (MDR) bacteria. Using the agar well diffusion method, Syzygium aromaticum exhibited significant antibacterial activity, particularly against Salmonella typhi (30.66 mm inhibition zone), while Nigella sativa was effective only against Staphylococcus aureus (19 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for Syzygium aromaticum ranged from 3.53 to 7.06 mg/mL, indicating stronger antibacterial properties than Nigella sativa (MIC: 12.7 mg/mL, MBC: 22.5 mg/mL). GC-MS analysis revealed that Syzygium aromaticum contained bioactive compounds like Diglycolic acid (76.59%) and Eugenol (2.06%), while Nigella sativa was dominated by Heptasiloxane (80.83%) and Thymoquinone (2.66%). These findings suggest that Syzygium aromaticum essential oil could serve as a potent natural antimicrobial agent against MDR pathogens.

Clonal and horizontal transmission of carbapenem-resistant Enterobacterales strains and genes via flies.

Antimicrobial resistance (AMR) is one of the most pressing global public health challenges; in particular, the rapid dissemination of carbapenem-resistant Enterobacterales (CRE) is emerging as a significant concern worldwide. Flies, serving as carriers of pathogens, pose a potential threat in the transmission of antibiotic-resistant bacteria (ARB) between animals and humans. The aim of this study was to evaluate and reveal the potential risk of AMR spread by flies. A total of 450 flies were collected from four farms, four rural areas, and four urban areas in Dengfeng, Henan, China. To select CRE strains on the surface of flies, three flies sampled from the same geographical location were arbitrarily selected and placed into one tube of brain heart infusion broth (BHI), and the supernatant was screened using CHROMagar™ mSuperCARBA culture medium. Different colors and shapes of colonies were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA sequencing. Antimicrobial susceptibility testing for CRE strains was performed using broth microdilution. All CRE strains were whole-genome sequenced. Short-read sequencing was performed using MGISEQ-2000 and long-read sequencing was conducted using GridION. Totally, 150 BHI tubes were screened for CRE strains, and 33 strains were identified as CRE positive. In 24 mSuperCARBA plates, only one species of CRE strain was isolated from each plate. In three plates, two different species of CRE strains were identified in each plate. In one plate, three different species of CRE strains were simultaneously isolated. Carbapenem resistance genes were detected in 81.8% of CRE strains, and blaNDM-1 was predominant (66.7%). No significant correlations between carbapenem-resistant phenotypes and carbapenem resistance genes were observed. The complete genomes of all 33 strains were obtained. Genome analysis revealed that clonal transmission events may have occurred among different farms and rural areas. Phylogenetic analysis revealed that blaNDM-1 IncFII plasmids could break bacterial species barrier for cross-host transmission in diverse areas. To understand and control the transmission of AMR from the perspective of One Health, it is imperative to enhance surveillance of ARB, antibiotic resistance genes, and antibiotic-resistant plasmids in flies.

PASS-ASSISTED PREDICTION OF NOVEL TETRACYCLINE HYBRIDS

Objective: The study aimed to determine the biological activity of various novel tetracycline hybrids using way 2 drug platform's online pass software. Methods: Novel structures were designed computationally by hybridization of 9-amino tetracycline with various phyotchemicals using various covalent linkers and prediction of biological activity was done using online pass software. Results: The study investigated showed the antibacterial activity of almost all hybridized tetracycline compounds. The PASS predictions suggested that modifications at the 9th position of tetracycline with various phytochemicals enhanced the antibacterial activity or retained the antibacterial activity for several of the designed structures when compared with standard tetracycline. Conclusion: With an alarming increase of antibiotic resistance, we must identify ways to combat these diseases. This work implies that combining antimicrobials with phytochemicals can create new antimicrobial-photochemical conjugates, potentially addressing antimicrobial resistance in bacteria. Tetracycline hybrids can be used in the future to produce many more hybrids, potentially embarking in a new era of medicine research.

Synthesis and Antimicrobial Activity of 3-Alkylidene-2-Indolone Derivatives

The escalating threat of antibiotic-resistant bacteria and fungi underscores an urgent need for new antimicrobial agents. This study aimed to synthesize and evaluate the antimicrobial activities of two series of 3-alkylidene-2-indolone derivatives. We synthesized 32 target compounds, among which 25 exhibited moderate to high antibacterial or antifungal activities. Notably, compounds 10f, 10g, and 10h demonstrated the highest antibacterial activity with a minimum inhibitory concentration (MIC) of 0.5 μg/mL, matching the activity of the positive control gatifloxacin against three Gram-positive bacterial strains: Staphylococcus aureus ATCC 6538, 4220, and Methicillin-resistant Staphylococcus aureus ATCC 43300. Moreover, the three most active compounds 10f, 10g, and 10h were evaluated for their in vitro cytotoxicity in the HepG2 cancer cell line and L-02; only compound 10h was found to exert some level of cytotoxicity. These findings suggest that the synthesized 3-alkylidene-2-indolone derivatives hold potential for further development as antibacterial agents.

Metal-phenolic nanoparticles enhance low temperature photothermal therapy for bacterial biofilm in superficial infections.

Bacterial infections, especially induced by multidrug-resistant pathogens, have become a significant global health concern. In the infected tissues, biofilms not only serve as a source of nutrients but also act as protective barriers that impede antibiotic penetration. Herein, we developed tea polyphenols epigallocatechin gallate (EGCG) Au nanoparticles (E-Au NPs) through direct one-step self-assembly methods by EGCG chelating with Au ions to eradicate antibiotic-resistant bacteria methicillin-resistant Staphylococcus aureus (MRSA) and prevent the formation of biofilm under near-infrared (NIR) irradiation. The outstanding antibacterial effect involved in mild photothermal therapy, reactive oxygen species production, pathogenicity-related genes regulation, and quinoprotein formation that were specific to the polyphenol-based NPs. The excellent antibacterial and anti-inflammatory therapeutic efficacy of E-Au NPs was validated and topically applied in murine MRSA-infected skin wounds and keratitis model in vivo to kill bacteria, reduce the inflammation response and promote wound healing. Furthermore, the ophthalmic and systemic biosafety profiles were thoroughly evaluated while no significant side effects were revealed achieving a balance between high-efficiency antibacterial properties and biocompatibility. This study provides an effective therapeutic agent of metal-phenolic materials for superficial tissue infection with favorable prognosis and potential in clinical translation.

In Vivo Efficacy of a Nanoconjugated Glycopeptide Antibiotic in Silkworm Larvae Infected by Staphylococcus aureus

To contrast the rapid spread of antibiotic resistance in bacteria, new alternative therapeutic options are urgently needed. The use of nanoparticles as carriers for clinically relevant antibiotics represents a promising solution to potentiate their efficacy. In this study, we used Bombyx mori larvae for the first time as an animal model for testing a nanoconjugated glycopeptide antibiotic (teicoplanin) against Staphylococcus aureus infection. B. mori larvae might thus replace the use of mammalian models for preclinical tests, in agreement with the European Parliament Directive 2010/63/EU. The curative effect of teicoplanin (a last resort antibiotic against Gram-positive bacterial pathogens) conjugated to iron oxide nanoparticles was assessed by monitoring the survival rate of the larvae and some immunological markers (i.e., hemocyte viability, phenoloxidase system activation, and lysozyme activity). Human physiological conditions of infection were reproduced by performing the experiments at 37 °C. In this condition, nanoconjugated teicoplanin cured the bacterial infection at the same antibiotic concentration of the free counterpart, blocking the insect immune response without causing mortality of silkworm larvae. These results demonstrate the value and robustness of the silkworm as an infection model for testing the in vivo efficacy of nanoconjugated antimicrobial molecules.

Investigation of Antibiotic Resistance of E. coli Associated with Farm Animal Feces with Participation of Citizen Scientists

This paper presents the findings of a large-scale study on antibiotic resistance in bacteria found in farm animal feces across Russia. The study included 6578 samples of farm animal manure from 13 regions in Russia, with the help of citizen scientists. Molecular and microbiological methods were used to analyze 1111 samples of E. coli. The microbiological analysis focused on culturing the microorganisms present in the fecal samples on selective media for E. coli and evaluating the sensitivity of the bacteria to different antibiotics, including ampicillin, tetracycline, chloramphenicol, cefotaxime, and ciprofloxacin. The molecular analysis involved isolating the genomic DNA of the bacteria and conducting PCR assays to detect the vanA, vanB, and mcr-1 antibiotic resistance genes. The results demonstrated significant differences in antibiotic sensitivity of the samples that are morphologically identical to E. coli from different regions. For example, 98.0% and 82.5% of E. coli and other fecal bacterial isolates from the Omsk and Vologda regions lacked antibiotic resistance genes, while 97.7% of samples from the Voronezh region possessed three resistance genes simultaneously. The phenotypic antibiotic sensitivity test also revealed regional differences. For instance, 98.1% of fecal bacterial samples from cattle in the Udmurt Republic were sensitive to all five antibiotics tested, whereas 92.8% of samples from the Voronezh region showed resistance to all five antibiotics. The high level of antibiotic resistance observed may be attributed to their use in farming practices. The distinctive feature of our research is that comprehensive geographical coverage was achieved by using a citizen science platform. Citizen scientists, specifically students from colleges and universities, were responsible for the collection and initial analysis of samples. The project attracted 3096 student participants, enabling the collection and analysis of a significant number of samples from various locations in Russia.

Assessment of Antibiotic Resistance in Groundwater Bacterial Strains: A Community-based Study

Background: The microbial quality of private and community water supply from groundwater is mostly not monitored nor assessed by any established government agencies in Nigeria. Contamination by pathogenic and antimicrobial resistant microbial agent, and the potential of resistant genes transfer from environmental bacteria to human pathogens is a major risk for public health in these water systems. Aim: This study was aimed at evaluating the microbiological quality and safety in terms of antibiotic resistance bacterial profile of groundwater sources in a typical peri-urban settlement in Nigeria. Methodology: Bacterial contaminants were isolated by membrane filtration technique, characterized and analyzed using standard microbiological approach. Results: A total of 22 and 8 Gram negative and positive bacteria respectively were isolated. The isolates comprised 7 bacterial genera with Klebsiella and Enterobacter species having the highest incidence of 20% respectively, followed by Bacillus (17%) and least being Shigella with 7% incidence. All the isolates were 100% resistant to cefotaxime, followed by 76.7% and 73.3% resistant to vancomycin and meropenem respectively. The least resistance of 3.3% was against ciprofloxacin. Resistance in borehole storage tank water was highest (80%) against vancomycin followed by 70% for meropenem, while 75% resistance was against vancomycin and meropenem respectively in the well water, Seventy-three percent (73%) of the isolates showed multidrug resistance (MDR) pattern, and a multiple antibiotic resistant index (MARI) ≥ 0.3. Conclusion: The results of this study suggest that groundwater source in the studied community is contaminated with antibiotic resistant bacteria and underscores the public health implication and concern for monitoring of groundwater supply in Nigerian communities.

HPB SO02 - Cutting surgical site infection rates in perihilar cholangiocarcinoma with informed changes to perioperative antibiotic prophylaxis: A quality improvement project in a UK hepatopancreatobiliary tertiary centre

Abstract Background Perihilar cholangiocarcinoma (pCCA) is the most common cancer of biliary epithelia. While potentially curative, surgical resection is associated with high morbidity and mortality. Surgical site infections (SSIs) are common and pernicious. Preoperative biliary instrumentation is universal: to confirm histological diagnosis and deploy stents to relieve jaundice. Patients receive multiple antibiotic courses as periprocedural prophylaxis and to treat cholangitis. They are at high risk of harbouring bacteria not quelled by perioperative prophylactic antibiotics given for other general surgical procedures. Studying the biliary microbiome, this quality improvement project sought to reduce SSIs through informed changes to local guidelines on perioperative antibiotic prophylaxis. Method Health records of all patients undergoing resection for pCCA in a UK hepatopancreatobiliary centre from February 2009 to January 2024 were analysed retrospectively (n=118). For all patients, we routinely sent intraoperative bile swabs for culture and sensitivity. Informed by these microbiology results, multidisciplinary discussion led to changes to local guidelines in March 2019. Formerly, cefuroxime and metronidazole were given on anaesthetic induction, with subsequent antibiotic choice and duration according to surgeon preference. New guidance stipulated teicoplanin and piperacillin/tazobactam be given on induction and for 72 hours postoperatively. We studied the impact of these changes on SSIs within 30 days. Results 75 patients received cefuroxime and metronidazole; 43 patients were given teicoplanin and piperacillin/tazobactam after the policy change. Proportions of patients who developed any SSI substantially fell following the guideline change (55% v 28%; p=0.0049), primarily owing to reductions in intraperitoneal collections (39% v 21%; p=0.047). Rates of deep (8% v 2%; p=0.21) and superficial incisional infections (8% v 5%; p=0.49) were not significantly affected. Associated secondary outcomes were drops in post-hepatectomy liver failure (17% v 5%; p=0.047), and 90-day mortality (16% v 5%; p=0.067), albeit the latter was not statistically significant. Conclusion Invasive investigative work-up, disease complications and exposure to multiple courses of antibiotics prior to resection of pCCA subject patients’ biliary systems to colonisation with antimicrobial-resistant bacteria. We urge centres that undertake these operations to introduce intraoperative bile cultures as a part of routine practice to inform local guidance on perioperative antimicrobial prophylaxis. We demonstrated effective antibiotics in the perioperative period can have enormous benefits to patient outcomes.

Detection and molecular characterization of carbapenem-resistant gram-negative bacterial isolates.

Antimicrobial-resistant bacteria (ARB) are responsible for increased mortality and morbidity. Therefore, this study focuses on evaluating traditional and molecular diagnostic tools of carbapenem-resistant gram-negative bacteria (CRGNB). In order to achieve this, 94 samples, from different patients' specimens, and surrounding environment, were collected from intensive care units (ICUs) at Ain Shams University Specialized Hospital and the National Cancer Institute, Cairo, Egypt. The swabs were cultured on appropriate media, including Chromogenic medium (HiCrome KPC Agar Base "HIMEDI AM1831"), and MacConkey-10µg imipenem disc resulting in 136 isolates with different culture characteristics. Next, the selected isolates were subjected to VITEK 2 machine and 16SrRNA (16S ribosomal RNA) sequencing. The sensitivity of HiCROME KPC agar for CRGNB detection was 99.3% and 94.7%, in reference to the MacConkey-disc and VITEK-2 methods, respectively. The HiCrome KPC agar assumptions for bacterial identification were not as consistent as those of VITEK 2 (with only 47.4% agreement) and 16SrRNA gene sequencing analysis. The approaches discussed in this study facilitate providing rapid diagnosis and treatment of CRGNB, which helps increase survival rates. HiCrome KPC agar is considered a relatively accurate and easy method that can be used in any laboratory. In addition, the selected strains were deposited in the gene bank with the accession numbers OR553657, OR553658, and OR553659. It is noteworthy that Genus Acinetobacter is the major CRGNB isolated from the patients and environmental surfaces in the hospitals. This highlights the importance of proper environmental and terminal cleaning procedures in healthcare facilities and applying control measures to ensure infection prevention.

Detection and genetic characterization of multidrug-resistant staphylococci isolated from public areas in an international airport.

The environmental realm has been acknowledged as a pivotal arena for the emergence and propagation of antimicrobial resistance. To further explore insight into antimicrobial resistance dynamics beyond clinical and veterinary settings, we embarked on an environmental surveillance initiative targeting the prevalence of antibiotic-resistant bacteria within the bustling confines of an international airport in Japan. Our findings illuminate a high prevalence of methicillin-resistant staphylococci (46.3%) on frequently contacted surfaces in the public domain. Notably, Staphylococcus haemolyticus and S. epidermidis emerged as the preeminent carriers of the mecA gene. Intriguingly, we encountered a virulent strain of livestock-associated MRSA harboring a PVL-positive ST1232 clone, CC398 lineage. Further scrutiny unveiled a repertoire of resistance mechanisms, the methicillin-resistant isolates exhibited two or more resistance genes conferring resistance against different types of antibiotics, including beta-lactams, macrolides, lincosamides, aminoglycosides, chloramphenicol, and fosfomycin. Revealing multidrug-resistant CoNS and a LA-MRSA across various surfaces in urban public areas unearths a looming public health hazard. Thus, implementation of molecular surveillance is imperative, augmenting our capacity for early detection and mitigation of the insidious spread and potential transfer of antibiotic resistance genes and virulence factors amidst urban settings, notably within pivotal nodes such as airports.

Visible-Light-Induced Rapid Elimination of Antibiotic Resistance Contaminations Using Graphitic Carbon Nitride Tailored with Carrier Confinement Domains.

Solar water disinfection facilitated by photocatalyst has been considered a viable point-of-use (POU) method for mitigating antibiotic resistance contaminations at the household or community levels. Here, density functional theory calculations are used to guide the fabrication of a carrier confinement domains (CCD)-decorated graphitic carbon nitride (CN) photocatalyst. The CCD integration effectively disrupts the electron distribution symmetry of CN, amplifies its local electron density, and facilitates the formation of long-range ordered structure, thereby enhancing charge separation efficiency. Importantly, the CCD directs the migration of photogenerated carriers to specific regions upon light illumination, effectively minimizing their spatial proximity. As a result, the overall reactive oxygen species level of the photocatalytic system is markedly elevated, with a twelvefold increase in H2O2 concentration, alongside a nearly two-order-of-magnitude rise in •O2 - and •OH steady-state concentrations. Remarkably, a record-high disinfection efficiency is attained, successfully inactivating 7 log of antibiotic-resistant bacteria within 30min. Additionally, the photocatalyst can be integrated into a continuous-flow fixed-bed reactor, facilitating clean water production for up to 60h at a rate of 121Lm-2day-1, highlighting its significant potential for POU applications.

Comprehensive Study of Antibiotic Resistance in Enterococcus spp.: Comparison of Influents and Effluents of Wastewater Treatment Plants

Background/Objectives: The spread of antibiotic resistance, particularly through Enterococcus spp., in wastewater treatment plants (WWTPs) poses significant public health risks. Given that research on antibiotic-resistant enterococci and their antibiotic-resistance genes in aquatic environments is limited, we evaluated the role of Enterococcus spp. in WWTPs by comparing the antibiotic resistance rates, gene prevalence, biofilm formation, and residual antibiotics in the influent and effluent using culture-based methods. Methods: In 2022, influent and effluent samples were collected from 11 WWTPs in South Korea. Overall, 804 Enterococcus strains were isolated, and their resistance to 16 antibiotics was assessed using the microdilution method. Results: High resistance to tetracycline, ciprofloxacin, kanamycin, and erythromycin was observed. However, no significant differences in the overall resistance rates and biofilm formation were observed between the influent and effluent. Rates of resistance to ampicillin, ciprofloxacin, and gentamicin, as well as the prevalence of the tetM and qnrS genes, increased in the effluent, whereas resistance rates to chloramphenicol, florfenicol, erythromycin, and tylosin tartrate, along with the prevalence of the optrA gene, decreased. E. faecium, E. hirae, and E. faecalis were the dominant species, with E. faecalis exhibiting the highest resistance. Conclusions: Our results suggest that WWTPs do not effectively reduce the rates of resistant Enterococcus spp., indicating the need for continuous monitoring and improvement of the treatment process to mitigate the environmental release of antibiotic-resistant bacteria.

ACTINOBACTERIAL DIVERSITY DETERMINATION IN MALAYSIAN BRIS (BEACH RIDGES INTERSPERSED WITH SWALES) SOIL BY CULTURE-DEPENDENT APPROACH

Globally, the rapid emergence of antibiotic-resistant bacteria poses a major threat to public health, threatening the effectiveness of antibiotics. Addressing the crisis of antimicrobial resistance requires urgency in new drug discovery and the effort in finding novel compounds is dramatically evolving. However, one of the main obstacles is the rediscovery of known compounds from natural resources. To overcome this challenge, exploring underexploited location for new resource of actinomycetes, such as Beach Ridges Interspersed with Swales (BRIS) soil in Malaysia, was selected. Soil samples from Jambu Series and Rudua Series in Setiu, Terengganu were collected and analysed. A total of 87 actinomycetes strains were isolated on yeast malt agar (ISP2), Actinomyces agar and Zobell marine agar, with the highest number from the Jambu series using serial dilution and spread plate method. Antimicrobial screening revealed that 31 isolates exhibited activity against ESKAPE pathogens, with 28 and 12 isolates showing activity against Gram-positive and Gram-negative bacteria, respectively. These isolates showed strong inhibiting response towards one or more ESKAPE pathogens. This study highlights the potential of BRIS soil as an underexploited habitat for discovering actinobacterial communities which could lead to the discovery of a new potential antimicrobial producer to serve as novel drug leads.

Impact of salmon farming in the antibiotic resistance and structure of marine bacterial communities from surface seawater of a northern Patagonian area of Chile

BackgroundAquaculture and salmon farming can cause environmental problems due to the pollution of the surrounding waters with nutrients, solid wastes and chemicals, such as antibiotics, which are used for disease control in the aquaculture facilities. Increasing antibiotic resistance in human-impacted environments, such as coastal waters with aquaculture activity, is linked to the widespread use of antibiotics, even at sub-lethal concentrations. In Chile, the world's second largest producer of salmon, aquaculture is considered the primary source of antibiotics residues in the coastal waters of northern Patagonia. Here, we evaluated whether the structure and diversity of marine bacterial community, the richness of antibiotic resistance bacteria and the frequency of antibiotic resistance genes increase in communities from the surface seawater of an area with salmon farming activities, in comparison with communities from an area without major anthropogenic disturbance.ResultsThe taxonomic structure of bacterial community was significantly different between areas with and without aquaculture production. Growth of the culturable fraction under controlled laboratory conditions showed that, in comparison with the undisturbed area, the bacterial community from salmon farms displayed a higher frequency of colonies resistant to the antibiotics used by the salmon industry. A higher adaptation to antibiotics was revealed by a greater proportion of multi-resistant bacteria isolated from the surface seawater of the salmon farming area. Furthermore, metagenomics data revealed a significant higher abundance of antibiotic resistant genes conferring resistance to 11 antibiotic families in the community from salmon farms, indicating that the proportion of bacteria carrying the resistance determinants was overall higher in salmon farms than in the undisturbed site.ConclusionsOur results revealed an association between bacterial communities and antibiotic resistance from surface seawater of a coastal area of Chile. Although the total bacterial community may appear comparable between sites, the cultivation technique allowed to expose a higher prevalence of antibiotic resistant bacteria in the salmon farming area. Moreover, we demonstrated that metagenomics (culture-independent) and phenotypic (culture-dependent) methods are complementary to evaluate the bacterial communities’ risk for antibiotic resistance, and that a human—influenced environment (such as salmon farms) can potentiate bacteria to adapt to environmental stresses, such as antibiotics.