International Journal of Antimicrobial Agents最新文献

{"title":"Access to phage therapy at Hospices Civils de Lyon in 2022: Implementation of the PHAGEinLYON Clinic programme.","authors":"Tristan Ferry, Myrtille Le Bouar, Thomas Briot, Tiphaine Roussel-Gaillard, Thomas Perpoint, Sandrine Roux, Florence Ader, Florent Valour, Behrouz Kassai, Inesse Boussaha, Marietou Ndiaye, Fabien Craighero, Clément Javaux, Sébastien Lustig, Cécile Batailler","doi":"10.1016/j.ijantimicag.2024.107372","DOIUrl":"10.1016/j.ijantimicag.2024.107372","url":null,"abstract":"<p><strong>Objectives: </strong>To describe the PHAGEinLYON Clinic programme, set up in 2022 to improve access to phage therapy in France using pharmaceutical-grade phages.</p><p><strong>Methods: </strong>All phage therapy requests received during 2022 were collected prospectively, and reviewed retrospectively to analyse the decision and the patient care pathway (NCT05883995).</p><p><strong>Results: </strong>Of 143 requests for phage therapy, the indication was confirmed at a multidisciplinary team meeting for 57 (40%) patients. Forty-four patients were infected with bacteria that could be targeted easily by phages in France. Finally, 33 patients were treated, including 26 at the study institution, through a compassionate access programme or in a clinical trial. The main indication were complex bone and joint infections, endovascular infection and lung infection. In order to manage these patients, 172 pharmaceutical phage cocktails targeting Staphylococcus aureus and/or Pseudomonas aeruginosa were prepared: 57 for local injection and 99 for intravenous injection. During follow-up, 18 (69%) patients showed a favourable clinical evolution, and six (23%) patients required subsequent phage therapy, either with the same phage with greater exposure, or with a different phage from elsewhere.</p><p><strong>Conclusions: </strong>Implementation of the PHAGEinLYON Clinic programme in 2022 was associated with groundbreaking access to phage therapy in France.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107372"},"PeriodicalIF":4.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142567496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic and growth fitness study of extended-spectrum β-lactamase-producing Escherichia coli from bloodstream infections after introduction of a national 4C antimicrobial stewardship policy in Scotland.","authors":"Istifanus Nkene, Susanth Alapati, Antonio Ribeiro, Ijeoma Okoliegbe, Sreedevi Unnikrishnan, Corinne Ironside, Becky Wilson, Karolin Hijazi","doi":"10.1016/j.ijantimicag.2024.107380","DOIUrl":"10.1016/j.ijantimicag.2024.107380","url":null,"abstract":"<p><strong>Background: </strong>Extended-spectrum β-lactamase-producing Escherichia coli remains a major cause of hospital-acquired bloodstream infections in countries with high antimicrobial stewardship compliance.</p><p><strong>Methods: </strong>Isolates from bloodstream infections that occurred between 2010 and 2020 in a tertiary-level hospital in North-East Scotland soon after introduction of the '4C' antimicrobial stewardship policy were analysed for phylogenetic structure, antimicrobial resistance, plasmid, and virulence gene carriage. Growth fitness was measured in kinetic assays. Non-metric-multidimensional-scaling was used to evaluate clonal relationships, antimicrobial resistance, and virulence profiles in early and later years after the 4C policy introduction. Clonal and fitness trends over the study period were determined by generalised additive modelling. The relationship between clonal type, antimicrobial resistance, and fitness was evaluated by linear regression.</p><p><strong>Results: </strong>Three hierarchical phylogenetic clusters were identified, with the most dominant cluster (O25:H4/fimH30) including all, and nearly exclusively, Clade C ST131 isolates as well as minor non-ST131 sequence types. The prevalence of ST131 was largely stable over the study period. Resistance to aminoglycosides and aztreonam in ST131 was lower (P = 0.019 and P = 0.004, respectively) during later years (2016-2020) by 28% on average compared to early years soon after 4C policy implementation (2010-2014). Carriage of virulence factors involved in bacterial adaptation was higher in ST131 compared to non-ST131 but mostly stable in early vs. later years. Growth fitness of ST131 was lower than non-ST131 and declined steadily in later years (P < 0.0001).</p><p><strong>Conclusions: </strong>Despite stable virulence factor carriage, population structure, and resistance to cephalosporins, we show increased susceptibility of ST131 to aminoglycosides and aztreonam and concurrent fitness decline years after the introduction of the 4C policy.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107380"},"PeriodicalIF":4.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HIV-1 viral decay in blood and semen in antiretroviral-naïve adults initiating dolutegravir/lamivudine vs. bictegravir/emtricitabine/tenofovir alafenamide.","authors":"Yongjian Liu, Ran Wang, Lijun Sun, Aixin Li, Zhengyang Li, Qian Kang, Yuxin Feng, Shiyun Lv, Yuanyi Zhai, Rui Li, Wei Hua, Xi Wang, Yue Gao, Zhangli Wang, Yuguang Feng, Jingwan Han, Lei Jia, Xiaolin Wang, Bohan Zhang, Hanping Li, Jingyun Li, Tong Zhang, Hao Wu, Lin Li, Lili Dai","doi":"10.1016/j.ijantimicag.2024.107396","DOIUrl":"10.1016/j.ijantimicag.2024.107396","url":null,"abstract":"<p><strong>Background: </strong>Co-formulated dolutegravir and lamivudine (DTG/3TC) is recommended as the first-line antiretroviral therapy (ART); however, the data on the viral decay in seminal plasma (SP) and blood plasma (BP), as well as changes in inflammatory biomarkers in BP, remain limited among antiretroviral-naïve people with HIV (PWH) receiving DTG/3TC. A prospective observational cohort study was conducted to compare the impact of DTG/3TC vs. bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) on viral decay kinetics and changes in inflammatory biomarkers in antiretroviral-naïve PWH.</p><p><strong>Methods: </strong>Newly diagnosed PWH who initiated BIC/FTC/TAF (n=57) or DTG/3TC (n=43) were enrolled. BP and SP were collected at 0, 4, 12, 24, and 48 weeks after ART initiation. The primary endpoint was viral suppression of HIV-1 in BP and SP at week 48. Secondary endpoints included changes in HIV-1 DNA levels and inflammatory biomarkers over the 48-week follow-up.</p><p><strong>Results: </strong>Overall, 96 (96.0%) PWH completed the 48-week follow-up (DTG/3TC, n=40; BIC/FTC/TAF, n=56). Viral suppression rates in BP and SP were comparable in the BIC/FTC/TAF and DTG/3TC groups in the per-protocol analyses at week 48 (BP, 96.4% vs. 100%, P=0.519; SP, 100% vs. 100%, P>0.999). Both regimens demonstrated similar effectiveness in reducing HIV-1 RNA levels in BP (3.0 vs. 3.1 log₁₀ copies/mL) and SP (0.9 vs. 1.2 log₁₀ copies/mL). There were no statistically significant differences in the reductions in HIV-1 DNA levels and changes in inflammatory biomarkers over the 48-week follow-up.</p><p><strong>Conclusion: </strong>These findings indicated comparable effectiveness of DTG/3TC vs. BIC/FTC/TAF in achieving viral suppression in BP and SP, and similar changes in inflammatory biomarkers in BP.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107396"},"PeriodicalIF":4.9,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142755101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the antibacterial activity of engineered phage ФEcSw endolysin against multi-drug-resistant Escherichia coli strain Sw1.","authors":"Maheswaran Easwaran, Rajiv Gandhi Govindaraj, Misagh Naderi, Michal Brylinski, Mahanama De Zoysa, Hyun-Jin Shin","doi":"10.1016/j.ijantimicag.2024.107395","DOIUrl":"10.1016/j.ijantimicag.2024.107395","url":null,"abstract":"<p><strong>Objective: </strong>The emergence of bacteriophage-encoded endolysins hold significant promise as novel antibacterial agents, particularly against the growing threat of antibiotic-resistant bacteria. Therefore, we investigated the phage ФEcSw endolysin to enhance the lytic activity against multi-drug-resistant Escherichia coli Sw1 through site-directed mutagenesis (SDM) guided by in silico identification of critical residues.</p><p><strong>Methods: </strong>A computational analysis was conducted to elucidate the protein folding pattern, identify the active domains, and recognize critical residues of ФEcSw endolysin. Structural similarity-based docking simulations were employed to identify residues potentially involved in both recognition and cleavage of the bacterial peptidoglycan. Phage endolysin was amplified, cloned, expressed, and purified from phage ФEcSw. Pure endolysin (EL) activity was subsequently validated through SDM.</p><p><strong>Results: </strong>Our studies revealed both open and closed conformations of ФEcSw endolysin within specific residue ranges (51-60 and 128-141). Notably, the active site was identified and contains the crucial catalytic residues, Glu19 and Asp34. A time-kill assay demonstrated that the holin (HL) - EL effectively reduced E. coli Sw1 growth by 46% within 12 h. Furthermore, treatment with HL, EL, and HL-EL significantly increased bacterial membrane permeability (11%, 74%, and 85%, respectively) within just 1 h. Importantly, SDM identified a double mutant (K19/H34) of the endolysin exhibiting the highest lytic activity compared to the wild-type and other mutants (E19D, E19K, D34E, and D34H) due to increase net charge from +3.23 to +6.29.</p><p><strong>Conclusions: </strong>Our findings demonstrate that phage endolysins and HLs or engineered endolysin hold significant potential as therapeutic agents to combat multidrug-resistant bacterial infections.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107395"},"PeriodicalIF":4.9,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142755100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toxicokinetic Profiling of VRP-034: Evaluating its Potential in Mitigating Polymyxin B-Associated Nephrotoxicity.","authors":"Kamlesh Vishwakarma, Anmol Bisht, Parveen Kumar, Satish Kumar, Jawed Akhter, Anurag Payasi, Saransh Chaudhary, Anmol Aggarwal","doi":"10.1016/j.ijantimicag.2024.107393","DOIUrl":"https://doi.org/10.1016/j.ijantimicag.2024.107393","url":null,"abstract":"<p><p>This study assessed the nephrotoxicity and toxicokinetic profile of VRP-034 (novel formulation of polymyxin B [PMB]) compared to marketed PMB over a seven-day repeat-dose regimen. Three objectives were pursued: evaluating PMB pharmacokinetics in both groups, alongside assessing VRP-034's impact on mitigating PMB-associated kidney injury; analyzing kidney injury reversibility; and validating novel kidney injury biomarkers against traditional markers using histopathology scoring. 68 Sprague-Dawley rats were divided into three groups: 30 each for marketed PMB and VRP-034 groups, and 8 for control. Animals received drugs at 6 mg/kg subcutaneously every 8 hours (HED ∼3 mg/kg/day). Toxicokinetic evaluations were conducted on selected animals on days 1, 2, 4 and 7 (after 3rd, 6th, 12th and 21st dose), while remaining animals were observed for an additional 7-days of treatment-free period. Samples were collected up to 12h post-administration, followed by necropsy and histopathological examinations. Plasma PMB concentrations were quantified; and kidney injury biomarkers, oxidative stress and anti-inflammatory markers were evaluated. Receiver operator characteristic curve analysis was performed to validate kidney injury biomarkers against histopathological grading. Results showed similar plasma PMB concentrations and pharmacokinetics parameters between both treatment groups. However, VRP-034 group exhibited significantly lower nephrotoxicity, with reduced kidney injury biomarkers levels, and diminished oxidative stress, and inflammation levels compared to marketed PMB group. Histopathological examination confirmed reduced renal damage in the VRP-034 group. Novel kidney injury biomarkers demonstrated superior sensitivity, specificity, and early detection capability over traditional markers. In conclusion, VRP-034 demonstrated reduced nephrotoxicity compared to marketed PMB, suggesting its potential as a safer alternative.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107393"},"PeriodicalIF":4.9,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ceftazidime-avibactam (CAZ-AVI) pharmacokinetics in critically ill patients undergoing continuous venovenous hemodiafiltration (CVVHDF).","authors":"Amaury O'Jeanson, Konstantinos Ioannidis, Elisabet I Nielsen, Lamprini Galani, Aghavni Ginosyan, Harry Paskalis, Irena Loryan, Helen Giamarellou, Lena E Friberg, Ilias Karaiskos","doi":"10.1016/j.ijantimicag.2024.107394","DOIUrl":"10.1016/j.ijantimicag.2024.107394","url":null,"abstract":"<p><strong>Purpose: </strong>To investigate the pharmacokinetics (PK) of ceftazidime-avibactam (CAZ-AVI) in critically ill patients undergoing continuous venovenous hemodiafiltration (CVVHDF), and compare with a general phase III trial population.</p><p><strong>Methods: </strong>A prospective PK study was conducted in critically ill patients who received CVVHDF for acute kidney injury, treated with CAZ-AVI (1000/250 mg or 2000/500 mg q8h). Plasma and CVVHDF-circuit samples were collected to determine CAZ-AVI concentrations. Individual PK parameters at steady-state were estimated using non-compartmental analysis. For visual comparison, plasma concentrations from CVVHDF patients were overlaid with simulated data from patients not receiving CVVHDF based on previously developed population PK models.</p><p><strong>Results: </strong>A total of 35 plasma samples and 16 CVVHDF-circuit samples were obtained from four patients, with two patients sampled on two separate occasions. Median total clearance and volume of distribution were 4.54 L/h and 73.2 L for CAZ and 10.5 L/h and 102 L for AVI, respectively. Median contribution of CVVHDF to total clearance was 19.8% for CAZ and 5.3% for AVI. Observed CAZ-AVI PK profiles were generally within the 90% confidence interval of model predictions, but the observed concentrations were notably lower early (0-2 h) and higher later (4-8 h) in the dosing interval, suggesting a higher volume of distribution.</p><p><strong>Conclusions: </strong>These results suggest that the CAZ-AVI dose regimens used in this study can be applicable in critically ill patients undergoing CVVHDF, despite the different shape of the PK profiles observed in this population. Further research with a larger patient cohort is warranted to validate and refine these findings.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107394"},"PeriodicalIF":4.9,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142710114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"International Society of Antimicrobial Chemotherapy (ISAC) News and Information Page","authors":"","doi":"10.1016/j.ijantimicag.2024.107391","DOIUrl":"10.1016/j.ijantimicag.2024.107391","url":null,"abstract":"","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":"64 6","pages":"Article 107391"},"PeriodicalIF":4.9,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response regulator protein CiaR regulates the transcription of ccn-microRNAs and β-lactam antibiotic resistance conversion of Streptococcus pneumoniae.","authors":"Mei-Juan Yang, Meng-Jie Li, Li-Dan Huang, Xin-Wei Zhang, Yan-Ying Huang, Xiao-Yu Gou, Sui-Ning Chen, Jie Yan, Peng Du, Ai-Hua Sun","doi":"10.1016/j.ijantimicag.2024.107387","DOIUrl":"10.1016/j.ijantimicag.2024.107387","url":null,"abstract":"<p><strong>Background: </strong>Streptococcus pneumoniae does not produce β-lactamases, and its reduced susceptibility to β-lactam antibiotics is predominantly caused by mutations of penicillin-binding proteins (PBPs). However, mechanisms of non-PBP mutation-related β-lactam antibiotic resistance in pneumococcal strains remain poorly characterized.</p><p><strong>Methods: </strong>Susceptibility of S. pneumoniae ATCC49619 and its ciaR gene knockout, complemented, or overexpression mutant (ΔciaR, CΔciaR, or ciaR^OE) to penicillin, cefotaxime, and imipenem was detected using an E-test. Levels of pneumococcal ciaR-mRNA, 5 ccn-microRNAs, and 6 pbps-mRNAs were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Recombinant CiaR (rCiaR) binding to the promoters of ccn-microRNA genes was confirmed using electrophoresis mobility shift and chromatin immunoprecipitation assays. Sequence matching between the ccn-microRNAs and pbps-mRNAs was analyzed using IntaRNA software.</p><p><strong>Results: </strong>S. pneumoniae ATCC49619 was sensitive to the 3 β-lactam antibiotics, but overexpression of CiaR, a response regulator protein in 2-component system, caused the increase of MICs against these antibiotics. The ciaR^OE mutant exhibited the significantly increased transcription of ccn-microRNAs but notably decreased transcription of pbps-mRNAs; conversely, the ΔciaR mutant displayed decreased levels of ccn-microRNAs and increasesed transcription of pbps-mRNAs. rCiaR was able to bind to the promoters of all ccn-microRNA genes in vitro and within cells. The 3 antibiotics at 1/8 minimal inhibitory concentrations caused a significant increase in the ciaR-mRNA and ccn-microRNAs. The mRNA-binding seed sequences in the 5 ccn-microRNAs matched all the promoter-containing sequences of pbps-mRNAs.</p><p><strong>Conclusions: </strong>β-Lactam antibiotics at low concentrations induce non-PBP mutation-related antibiotic resistance conversion of S. pneumoniae by decrease of PBPs through the pathway of CiaR-mediated transcriptional increase of ccn-microRNAs and ccn-microRNA-dependent degradation of pbp-mRNAs.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107387"},"PeriodicalIF":4.9,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142681685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of bla_KPC-90 in Klebsiella pneumoniae associated with ceftazidime-avibactam resistance and the translocation & truncation of resistant genes mediated by IS26.","authors":"Weiwei Yang, Heping Xu, Yuanxun Zhao, Wannan Chen, Xiaobo Ma, Fupin Hu","doi":"10.1016/j.ijantimicag.2024.107388","DOIUrl":"10.1016/j.ijantimicag.2024.107388","url":null,"abstract":"<p><strong>Objectives: </strong>In this study, we discovered bla_KPC-90 in ceftazidime-avibactam resistant clinical isolates of K. pneumoniae from a patient with multiple comorbidities and investigated the resistance & transfer mechanism of bla_KPC-90.</p><p><strong>Methods: </strong>K. pneumoniae strains carrying bla_KPC-2 and bla_KPC-90 were isolated from the patient. Antimicrobial susceptibility tests and whole genome sequencing were performed to investigate the phenotype & genotype of strains. Conjugation assays, cloning experiment, kinetic parameters measuring, outer membrane protein SDS-PAGE and qRT-PCR were performed to explore the spread and antimicrobial resistance mechanisms.</p><p><strong>Results: </strong>KPC-90 isolates had an insertion of two amino acids (Thr180_Ser181 ins Tyr Thr) compared to the wildtype KPC-2. Antimicrobial susceptibility testing of isolates with KPC-90 vs. KPC-2 showed ceftazidime-avibactam MICs of >128 vs. 1-2 mg/L, meropenem-vaborbactam MICs of 4 vs. 1 mg/L, meropenem MICs of 4-8 vs. >128 mg/L and imipenem MICs of 0.5-1 vs. 64 mg/L. Analysis of kinetic parameters of KPC-90 compared to KPC-2 showed decreased hydrolysis of carbapenems and increased IC50 of avibactam. Genetic characterization of the plasmid revealed that IS26 could mediate the intramolecular inversion, translocation and truncation of the resistance determinant region.</p><p><strong>Conclusion: </strong>We have described the case of a patient infected with bla_KPC-90-carrying K. pneumoniae strains and investigated the mechanism of resistance to carbapenems and ceftazidime-avibactam associated with bla_KPC-2 and its variants. We have also focused on the functional diversity of IS26 in relation to antimicrobial resistance. In the future, it is crucial to pay more attention to the evolution and horizontal transmission of bla_KPC.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107388"},"PeriodicalIF":4.9,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eliminating the tigecycline resistance RND efflux pump gene cluster tmexCD-toprJ in bacteria using CRISPR/Cas9.","authors":"Lei Xu, Xiaoyu Lu, Yan Li, Patrick Butaye, Shangshang Qin, Zhiqiang Wang, Ruichao Li","doi":"10.1016/j.ijantimicag.2024.107390","DOIUrl":"10.1016/j.ijantimicag.2024.107390","url":null,"abstract":"<p><strong>Objectives: </strong>Tigecycline, a last-resort antibiotic in the tetracycline class, has been effective in treating infections caused by multidrug-resistant bacteria. However, the emergence of the tigecycline resistance gene cluster tmexCD-toprJ, which encodes a resistance-nodulation-division efflux pump, has significantly limited its therapeutic effectiveness. This study aims to explore the potential of CRISPR/Cas9-based plasmids to target and cleave tmexCD-toprJ gene cluster from bacterial plasmids and chromosomal integrative conjugative elements (ICEs), respectively.</p><p><strong>Methods: </strong>We developed two CRISPR/Cas9-based plasmids, pCas9Kill and pCas9KillTS. The pCas9Kill plasmid designed to eliminate tmexCD-toprJ from plasmids through electroporation, while the pCas9KillTS plasmid, delivered through conjugation, targeted tmexCD-toprJ within ICEs on the bacterial chromosome. The plasmid modifications were assessed using nanopore long-read sequencing.</p><p><strong>Results: </strong>Electroporation with the pCas9Kill plasmid resulted in the removal of tmexCD-toprJ from plasmids, restoring bacterial susceptibility to tigecycline. Nanopore sequencing revealed that the plasmids were repaired by insertion sequences after tmexCD-toprJ removal. In contrast, the pCas9KillTS plasmid introduced via conjugation to target tmexCD-toprJ gene cluster on ICEs within the chromosome. This approach led to chromosomal cleavage and subsequent bacterial cell death.</p><p><strong>Conclusion: </strong>Our results demonstrate that both plasmids effectively inactivated tmexCD-toprJ, with pCas9Kill restoring tigecycline susceptibility in plasmid-bearing strains and pCas9KillTS causing targeted cell death in chromosomal ICE-harbouring bacteria. This study highlights the potential of CRISPR/Cas9 systems in addressing antibiotic resistance, providing a promising strategy to combat tigecycline-resistant pathogens.</p>","PeriodicalId":13818,"journal":{"name":"International Journal of Antimicrobial Agents","volume":" ","pages":"107390"},"PeriodicalIF":4.9,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142647973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}