Antibiotics-Basel最新文献

{"title":"Infective Endocarditis by Biofilm-Producing Methicillin-Resistant <i>Staphylococcus aureus</i>-Pathogenesis, Diagnosis, and Management.","authors":"Ashlesha Kaushik, Helen Kest, Mangla Sood, Corey Thieman, Bryan W Steussy, Michael Padomek, Sandeep Gupta","doi":"10.3390/antibiotics13121132","DOIUrl":"https://doi.org/10.3390/antibiotics13121132","url":null,"abstract":"<p><p>Infective endocarditis (IE) is a life-threatening condition with increasing global incidence, primarily caused by <i>Staphylococcus aureus</i>, especially methicillin-resistant strains (MRSA). Biofilm formation by <i>S. aureus</i> is a critical factor in pathogenesis, contributing to antimicrobial resistance and complicating the treatment of infections involving prosthetic valves and cardiovascular devices. Biofilms provide a protective matrix for MRSA, shielding it from antibiotics and host immune defenses, leading to persistent infections and increased complications, particularly in cases involving prosthetic materials. Clinical manifestations range from acute to chronic presentations, with complications such as heart failure, embolic events, and neurological deficits. Diagnosis relies on the Modified Duke Criteria, which have been updated to incorporate modern cardiovascular interventions and advanced imaging techniques, such as PET/CT (positron emission tomography, computed tomography), to improve the detection of biofilm-associated infections. Management of MRSA-associated IE requires prolonged antimicrobial therapy, often with vancomycin or daptomycin, needing a combination of antimicrobials in the setting of prosthetic materials and frequently necessitates surgical intervention to remove infected prosthetic material or repair damaged heart valves. Anticoagulation remains controversial, with novel therapies like dabigatran showing potential benefits in reducing thrombus formation. Despite progress in treatment, biofilm-associated resistance poses ongoing challenges. Emerging therapeutic strategies, including combination antimicrobial regimens, bacteriophage therapy, antimicrobial peptides (AMPs), quorum sensing inhibitors (QSIs), hyperbaric oxygen therapy, and nanoparticle-based drug delivery systems, offer promising approaches to overcoming biofilm-related resistance and improving patient outcomes. This review provides an overview of the pathogenesis, current management guidelines, and future directions for treating biofilm-related MRSA IE.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672591/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Therapeutic Monitoring of Vancomycin Implemented by Eremomycin ELISA.","authors":"Inna A Galvidis, Yury A Surovoy, Vitaly R Sharipov, Pavel D Sobolev, Maksim A Burkin","doi":"10.3390/antibiotics13121133","DOIUrl":"https://doi.org/10.3390/antibiotics13121133","url":null,"abstract":"<p><strong>Background/objectives: </strong>Due to a narrow therapeutic window, side-effects, toxicities, and individual pharmacokinetics (PK) variability, WHO classifies vancomycin (VCM) as a \"watch antibiotic\" whose use should be monitored to improve clinical effectiveness. Availability and ease of use have made the immunoassay technique the basic tool for the therapeutic drug monitoring (TDM) of VCM concentrations.</p><p><strong>Methods: </strong>The present study describes the development of a TDM tool for VCM based on anti-eremomycin (ERM) antibody enzyme-linked immunosorbent assay (ELISA).</p><p><strong>Results: </strong>The optimized assay format based on coating a BSA-VCM conjugate allowed for the equal recognition of both VCM and ERM (100 and 104%) and was not influenced by concomitant antibiotics. Among the sample pretreatments studied, acetonitrile deproteinization was preferred to effectively remove the most likely matrix interferences and to provide 75-96% VCM recovery in the range of 3-30 mg/L, ensuring reliable determination of the key PK parameter, Ctrough. Higher peak concentrations were measured in more diluted samples. Several inflammatory indices, biochemical markers, and key proteins significantly different from normal in critically ill patients were investigated as assay interferers and were found not to interfere with VCM analysis. Serum samples (n = 108) from patients (n = 4) with extensive burn injuries treated with combined antibiotic therapy were analyzed for VCM using the developed assay and confirmed by LC-MS/MS, demonstrating good agreement.</p><p><strong>Conclusions: </strong>The approach used shows that the same analytical instrument is suitable for measuring structurally related analytes and is fully adequate for their therapeutic monitoring. Suboptimal exposure based on Ctrough values obtained with standard dosing regimens supports the use of TDM in these patients.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672653/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Survival Strategies of <i>Staphylococcus aureus</i>: Adaptive Regulation of the Anti-Restriction Gene <i>ardA</i>-H1 Under Stress Conditions.","authors":"Flavia Costa Carvalho de Andrade, Mariana Fernandes Carvalho, Agnes Marie Sá Figueiredo","doi":"10.3390/antibiotics13121131","DOIUrl":"https://doi.org/10.3390/antibiotics13121131","url":null,"abstract":"<p><p><b>Background/Objective</b>: The anti-restriction protein ArdA-H1, found in multiresistant <i>Staphylococcus aureus</i> (MRSA) strains from the ST239-SCC<i>mec</i>III lineage, inhibits restriction-modification systems, fostering horizontal gene transfer (HGT) and supporting genetic adaptability and resistance. This study investigates the regulatory mechanisms controlling <i>ardA-</i>H1 expression in <i>S. aureus</i> under various stress conditions, including acidic pH, iron limitation, and vancomycin exposure, and explores the roles of the Agr quorum sensing system. <b>Methods</b>: The expression of <i>ardA-</i>H1 was analyzed in <i>S. aureus</i> strains exposed to environmental stressors using real-time quantitative reverse transcription PCR. Comparisons were made between Agr-functional and Agr-deficient strains. In addition, Agr inhibition was achieved using a heterologous Agr autoinducing peptide. <b>Results</b>: The Agr system upregulated <i>ardA-</i>H1 expression in acidic and iron-limited conditions. However, vancomycin induced <i>ardA-</i>H1 activation specifically in the Agr-deficient strain GV69, indicating that an alternative regulatory pathway controls <i>ardA-</i>H1 expression in the absence of <i>a</i>gr. The vancomycin response in GV69 suggests that diminished quorum sensing may offer a survival advantage by promoting persistence and HGT-related adaptability. <b>Conclusion</b>: Overall, our findings provide new insights into the intricate relationships between quorum-sensing, stress responses, bacterial virulence, and genetic plasticity, enhancing our understanding of <i>S</i>. <i>aureus</i> adaptability in challenging environments.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672565/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diversity and Resistance Profiles of ESBL-Producing Gram-Negative Bacteria from Dairy Farms in Southern Türkiye.","authors":"Cemil Kürekci, Murat Yüksel, Büşra Gülay Celil Ozaslan, Sait Tan, Claudia Jäckel, Mirjam Grobbel, Jens Andre Hammerl","doi":"10.3390/antibiotics13121134","DOIUrl":"https://doi.org/10.3390/antibiotics13121134","url":null,"abstract":"<p><p><b>Background/Objectives:</b> The increasing occurrence of extended-spectrum β-lactamase (ESBL)-producing <i>Enterobacterales</i>, most commonly <i>Escherichia coli</i>, has become a serious problem. The aim of this study was to determine the presence of ESBL-producing Gram-negative bacteria in dairy cattle, goat and sheep farms located in southern Türkiye. <b>Methods:</b> Samples (409 quarter milk samples and 110 fresh faecal samples from cattle, 75 bulk tank milk samples and 225 rectal swab samples from goats and sheep) were subjected to selective isolation on MacConkey agar with ceftazidime (2 µg/mL). Isolates were identified by MALDI-ToF MS. The antimicrobial susceptibility profile of the isolates was determined by the broth microdilution method. To obtain a deeper insight into the genetic diversity of isolates substantially contributing to an efficient spread of their ESBL-determinants (23-MO00001: an <i>E. coli</i> from mastitis and 23-MO00002 <i>Citrobacter freundii</i>), the transmission potential and the genetic background of the plasmid carrying the <i>bla</i>_CTX-M determinant was studied with whole genome analysis using Illumina sequencing. <b>Results:</b> Of the samples tested, 47 from the bovine faecal samples, 1 from the subclinical mastitis milk sample, 9 from the goat/sheep rectal swab samples and 5 from the goat/sheep bulk tank milk samples had ceftazidime-resistant Gram-negative strains with the ESBL phenotype. Of the 33 ESBL-producing <i>E. coli</i> isolates, 66.6% were resistant to tetracycline, 57.6% to sulfamethoxazole, 48.9% to nalidixic acid, 42.4% to ciprofloxacin and 33.3% to trimethoprim. Pulsed field gel electrophoresis (PFGE) results showed that the majority of <i>E. coli</i> isolates (16/33) and all <i>Enterobacter</i> spp. isolates (n = 5) were not clonally related (80% similarity cut value). The sequenced strains were observed to efficiently transfer their ceftazidime resistance to the recipient strain <i>E. coli</i> J53 at 37 °C (transfer rates: 10¹-10² transconjugants per donor cell). S1-PFGE showed that the transconjugants J53(p23MO01-T1) and J53(p23MO02-T1) had acquired plasmids of about 82 kb and 55 kb plasmids, respectively. According to WGS results, the <i>E. coli</i> isolate was assigned to ST162, while the <i>C. freundii</i> isolate was assigned to ST95. <b>Conclusions:</b> This study demonstrates that dairy animals are reservoirs of ESBL-producing bacteria.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672566/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial Resistance Surveillance in Post-Soviet Countries: A Systematic Review.","authors":"Dariga Zhazykhbayeva, Dinagul Bayesheva, Zhanar Kosherova, Yuliya Semenova","doi":"10.3390/antibiotics13121129","DOIUrl":"https://doi.org/10.3390/antibiotics13121129","url":null,"abstract":"<p><strong>Background: </strong>Antimicrobial resistance (AMR) is a global health threat. AMR surveillance is crucial for understanding and controlling the spread of AMR. Surveillance systems can inform clinicians, guide health policymakers, and support effective AMR interventions. AMR surveillance data from former Soviet region countries are often limited, resulting in gaps in up-to-date knowledge.</p><p><strong>Methods: </strong>This systematic review was registered under the PROSPERO protocol CRD42024537799 and followed the PRISMA guidelines. Data from five databases (PubMed, MEDLINE, Embase, CINAHL, and CyberLeninka) and official sources were searched according to the inclusion criteria.</p><p><strong>Results: </strong>In total, 30 publications describing AMR surveillance and National Action Plans (NAPs) were included. Among the 15 countries, 14 (93.3%) have either developed a NAP or are in the process of implementing one; and 7 (46.7%) countries have a standardized AMR surveillance system. Almost all countries have reference laboratory centers, but nine (60%) countries have established standard testing methods in all sites. Only three (20%) countries have fully implemented quality assessment. There is an increasing tendency to involve and report AMR data to international networks, and countries will strengthen their AMR systems by adhering to international standards. The subgroup analysis revealed that Central and Western Asian countries are less developed in terms of AMR surveillance, which may encourage proactive engagement in AMR governance in these regions.</p><p><strong>Conclusions: </strong>This review is crucial for understanding the current efforts and improving AMR surveillance in former Soviet countries. The findings are promising and indicate that AMR surveillance is established in all reviewed countries, although at different levels.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672431/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the Dynamics of Antimicrobial Resistance: A Year-Long Surveillance (2023) at the Largest Infectious Disease Profile Hospital in Western Romania.","authors":"Sorina Maria Denisa Laitin, Luminita Mirela Baditoiu, Ruxandra Laza, Irina-Maria Stefan, Razvan Sebastian Besliu, Septimiu Radu Susa, Cristian Oancea, Emil Robert Stoicescu, Diana Manolescu, Corneluta Fira-Mladinescu","doi":"10.3390/antibiotics13121130","DOIUrl":"https://doi.org/10.3390/antibiotics13121130","url":null,"abstract":"<p><p><b>Background/Objectives</b><i>:</i> Antimicrobial resistance (AMR) is a critical global health threat, leading to increased morbidity, mortality, and healthcare costs. This study aimed to identify the most common bacterial pathogens and their resistance profiles from 2179 positive clinical cultures from inpatients at \"Victor Babes\" Hospital of Infectious Disease and Pneumoftiziology Timisoara in 2023. <b>Methods</b><i>:</i> Samples were collected from sputum, bronchial aspiration, hemoculture, urine, wound secretions, catheter samples, and other clinical specimens. <b>Results</b><i>:</i> Key pathogens identified included <i>Klebsiella pneumoniae</i>, <i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, and <i>Acinetobacter baumannii</i>, with notable resistance patterns, observed <i>K. pneumoniae</i> exhibited high resistance rates, notably 41.41% in Quarter 1, while <i>E. coli</i> showed 35.93% resistance in the same period. <i>S. aureus</i>, particularly MRSA, remained a persistent challenge, with 169 cases recorded over the year. <i>A. baumannii</i> and <i>P. aeruginosa</i> displayed alarming levels of multi-drug resistance, especially in Quarter 3 (88.24% and 22.02%, respectively). Although there was a general decline in resistance rates by Quarter 4, critical pathogens such as <i>S. aureus</i> and <i>K. pneumoniae</i> continued to exhibit significant resistance (81.25% and 21.74%, respectively). <b>Conclusions</b><i>:</i> The study's findings align with the broader antimicrobial resistance trends observed in Romania, where high resistance rates in <i>K. pneumoniae</i>, <i>E. coli</i>, <i>S. aureus</i> (MRSA), <i>Acinetobacter</i>, and <i>Pseudomonas</i> species have been widely reported, reflecting the country's ongoing struggle with multi-drug-resistant infections. Despite some reductions in resistance rates across quarters, the persistent presence of these resistant strains underscores the critical need for strengthened antimicrobial stewardship, infection control measures, and continuous surveillance to combat the growing threat of AMR in Romania and similar healthcare settings.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672838/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre- and Post-COVID-19 Antibiotic Consumption and Stewardship Program in a Southern Italian Hospital.","authors":"Maria Costantino, Valentina Giudice, Federica Campana, Alessandra Anna Iannelli, Pasqualina Scala, Walter Longanella, Francesco Marongiu, Emilia Anna Vozzella, Maria Giovanna Elberti, Maria Alfieri, Giovanni Boccia, Valeria Conti, Francesco De Caro, Amelia Filippelli","doi":"10.3390/antibiotics13121128","DOIUrl":"https://doi.org/10.3390/antibiotics13121128","url":null,"abstract":"<p><strong>Background/objectives: </strong>Antibiotic resistance is a growing global threat that significantly impacts public health and healthcare costs. The Italian National Action Plan on Antimicrobial Resistance (PNCAR) was introduced in 2017 to address this issue by improving antibiotic stewardship. This study aimed to evaluate the effectiveness of the PNCAR in enhancing antibiotic management practices in a hospital in southern Italy before and after its implementation.</p><p><strong>Methods: </strong>We conducted an observational monocentric study to analyze antibiotic consumption in a hospital setting before and after the COVID-19 pandemic (2019 and 2023) and to examine prescription appropriateness and the types of used antibiotics.</p><p><strong>Results: </strong>After PNCAR introduction, we recorded a significant increase in antibiotic prescription appropriateness and in Access antibiotic and targeted therapy usage, while Reserve antibiotics were prescribed in ~10% of the cases, with an increasing trend in 2023.</p><p><strong>Conclusions: </strong>Our study supports the importance of targeted stewardship initiatives, including continuous monitoring and education, to sustain antibiotic prescription appropriateness and to reduce antimicrobial resistance.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672782/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cloning and Functional Analysis of Skin Host Defense Peptides from Yakushima Tago's Brown Frog (<i>Rana tagoi yakushimensis</i>) and Development of Serum Endotoxin Detection System.","authors":"Taichi Aono, Saki Tamura, Yua Suzuki, Taichi Imanara, Ryosei Niwa, Yoshie Yamane, Tetsuya Kobayashi, Sakae Kikuyama, Itaru Hasunuma, Shawichi Iwamuro","doi":"10.3390/antibiotics13121127","DOIUrl":"https://doi.org/10.3390/antibiotics13121127","url":null,"abstract":"<p><p><b>Background/Objective:</b> Amphibian skin is a valuable source of host defense peptides (HDPs). This study aimed to identify HDPs with novel amino acid sequences from the skin of <i>Rana tagoi yakushimensis</i> and analyze their functions. <b>Methods:</b> cDNAs encoding HDP precursors were cloned and sequenced using RT-PCR and 3'-RACE. The novel HDPs were synthesized to evaluate their antimicrobial activity, antioxidant activity, and cytotoxicity. Antimicrobial activity was evaluated by way of broth microdilution and endotoxin- and β-glucan-binding capacity using an enzyme-linked endotoxin binding assay (ELEBA) and a modified ELEBA, respectively. <b>Results:</b> Nine cDNAs encoding precursors for various HDP families, including temporin, ranatuerin-2, brevinin-1, amurin-9, and a novel yakushimin peptide, were identified. Brevinin-1TYa exhibited antibacterial activity against <i>Staphylococcus aureus</i>, and brevinin-1TYa and amurin-9TYa induced morphological changes in <i>Escherichia coli</i> and <i>S. aureus</i>. Yakushimin-TYa, amurin-9TYa, and brevinin-1TYa showed concentration-dependent antibacterial effects against the plant pathogens <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> and <i>Clavibacter michiganensis</i> subsp. <i>michiganensis</i>. Amurin-9TYa demonstrated strong binding affinity to lipopolysaccharide, lipoteichoic acid, and β-glucan, exhibited antioxidant activity, and lacked cytotoxicity, making it a promising therapeutic candidate. Moreover, brevinin-1TYa showed strong cytotoxicity, whereas yakushimin-TYa exhibited weak cytotoxicity. <b>Conclusions:</b> These findings highlight the potential of these peptides, particularly amurin-9TYa, for future applications as antimicrobial and therapeutic agents.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672578/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic Analysis of Carbapenem-Resistant <i>Acinetobacter baumannii</i> Isolated from Bloodstream Infections in South Korea.","authors":"Wook Jong Jeon, Yoo Jung Kim, Ju Hui Seo, Jung Sik Yoo, Dong Chan Moon","doi":"10.3390/antibiotics13121124","DOIUrl":"https://doi.org/10.3390/antibiotics13121124","url":null,"abstract":"<p><strong>Background/objectives: </strong>Bloodstream infection by carbapenem-resistant <i>Acinetobacter baumannii</i> (CRAB) is a serious clinical problem worldwide. To study its clonal relationship and genetic features, we report the draft genome sequence of CRAB strains isolated from human blood in South Korea.</p><p><strong>Methods: </strong>Among <i>A. baumannii</i> strains isolated from patients at nine general hospitals in 2020, 12 CRAB strains of different genotypes were selected. Genomic DNA was sequenced using a combination of Illumina MiSeq and Oxford Nanopore MinION platforms. Antimicrobial susceptibility testing was performed using the disk diffusion method. Antimicrobial resistance and virulence genes were investigated in silico using the Center for Genomic Epidemiology server and the Virulence Factors Database.</p><p><strong>Results: </strong>The multilocus sequence types of isolates included ST191, ST195, ST357, ST369, ST451, ST469, ST491, ST784, ST862, ST1933, ST2929, and a novel type, ST3326. The predominant sequence type, ST191, demonstrated close genetic relationships with several isolates, including ST469, ST369, ST195, ST784, ST491, and ST3326, with ST3326 classified as a subgroup of ST191. We found 18 antimicrobial resistance genes and one quaternary ammonium compound resistance gene. All examined strains harbored <i>bla</i>_OXA-23, which is associated with carbapenem resistance. While variations in antibiotic and disinfectant resistance genes were observed, all isolates exhibited similar virulence factors, with the exception of the biofilm and capsule production genes.</p><p><strong>Conclusions: </strong>This nationwide report of the draft genome sequence of patient-derived strains provides valuable insights into the genomic features associated with clonal relationships and antimicrobial resistance of CRAB in bloodstream infections.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672490/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial Resistance Genes in <i>Legionella</i> from Artificial Water Systems: Findings from a Two-Year Study.","authors":"Bernardo Beirão Pereira, Mário Marrafa, Carolina Cruz, Lúcia Rodrigues, Filipa Nunes, Silvia Monteiro, Ricardo Santos, Rui Neves Carneiro, Célia Neto, Joana Aguilar, Nuno Rafael Ferreiro, Margarida Passanha, Gonçalo Candeias, Aida Fernandes, Paulo Paixão, Maria Jesus Chasqueira","doi":"10.3390/antibiotics13121121","DOIUrl":"https://doi.org/10.3390/antibiotics13121121","url":null,"abstract":"<p><strong>Background: </strong><i>Legionella</i> species are the causative agent of Legionnaires' disease and, as ubiquitous waterborne bacteria, are prone to antimicrobial resistance gene (ARG) acquisition and dissemination due to the antimicrobial contamination of natural environments. Given the potential health risks associated with ARGs, it is crucial to assess their presence in the <i>Legionella</i> population.</p><p><strong>Methods: </strong>The ARGs <i>lpeAB</i> and <i>tet56</i> were detected in 348 samples, isolates, and DNA extracts using conventional PCR. In a subset of <i>lpeAB</i>-positive isolates, azithromycin (AZT) MIC values were obtained using the EUCAST protocol and LpeAB activity was evaluated through an efflux pump inhibition assay.</p><p><strong>Results: </strong>The <i>lpeAB</i> gene was found in 19% (66/348) of samples, with higher detection rates in the <i>L. pneumophila</i> and <i>L. pneumophila</i> sg1 subgroups, at 30% and 41%, respectively. A positive association between <i>lpeAB</i> and <i>L. pneumophila</i> sg1 was found. The MIC values of the <i>lpeAB</i>-positive isolates ranged from 0.064 to 2 mg/L. LpeAB inhibition resulted in 2- and 4-fold MIC reductions in 10 of the 13 isolates analyzed. One sample each of <i>L. longbeacheae</i> and <i>L. bozemanae</i> was found to possess the <i>tet56</i> gene.</p><p><strong>Conclusions: </strong>The <i>lpeAB</i> gene is predominant in <i>L. pneumophila</i> sg1. A few isolates with the <i>lpeAB</i> gene exhibited MIC values below the EUCAST tentative highest MIC values for wild-type isolates. Expanding ARG monitoring in <i>Legionella</i> is essential to assess the public health risk of Legionnaires' disease.</p>","PeriodicalId":54246,"journal":{"name":"Antibiotics-Basel","volume":"13 12","pages":""},"PeriodicalIF":4.3,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11672855/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}