International Journal of Medical Microbiology最新文献

{"title":"In silico analysis and functional characterization of a leucine-rich repeat protein of Leptospira interrogans","authors":"","doi":"10.1016/j.ijmm.2024.151633","DOIUrl":"10.1016/j.ijmm.2024.151633","url":null,"abstract":"<div><p>Pathogenic spirochetes of the genus <em>Leptospira</em> are the causative agent of leptospirosis, a widely disseminated zoonosis that affects humans and animals. The ability of leptospires to quickly cross host barriers causing infection is not yet fully understood. Thus, understanding the mechanisms of pathogenicity is important to combat leptospiral infection. Outer membrane proteins are interesting targets to study as they are able to interact with host molecules. Proteins containing leucine-rich repeat (LRR) domains are characterized by the presence of multiple regions containing leucine residues and they have putative functions related to host-pathogen interactions. Hence, the present study aimed to clone and express the recombinant protein encoded by the LIC11098 gene, an LRR protein of <em>L. interrogans</em> serovar Copenhageni. <em>In silico</em> analyses predicted that the target protein is conserved among pathogenic strains of <em>Leptospira</em>, having a signal peptide and multiple LRR domains. The DNA sequence encoding the LRR protein was cloned in frame into the pAE vector, expressed without mutations in <em>Escherichia coli</em> and purified by His-tag chromatography. Circular dichroism (CD) spectrum showed that the recombinant protein was predominantly composed of β-sheets. A dose-dependent interaction was observed with cellular and plasma fibronectins, laminin and the complement system component C9, suggesting a possible role of the protein encoded by LIC11098 gene at the initial stages of infection.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000377/pdfft?md5=a4c205321a10694d63ab91a1343a9a98&pid=1-s2.0-S1438422124000377-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142129008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional profiling of CHAP domain-containing peptidoglycan hydrolases of Staphylococcus aureus USA300 uncovers potential targets for anti-staphylococcal therapies","authors":"","doi":"10.1016/j.ijmm.2024.151632","DOIUrl":"10.1016/j.ijmm.2024.151632","url":null,"abstract":"<div><p>The bacterial pathogen <em>Staphylococcus aureus</em> employs a thick cell wall for protection against physical and chemical insults. This wall requires continuous maintenance to ensure strength and barrier integrity, but also to permit bacterial growth and division. The main cell wall component is peptidoglycan. Accordingly, the bacteria produce so-called peptidoglycan hydrolases (PGHs) that cleave glycan strands to facilitate growth, cell wall remodelling, separation of divided cells and release of exported proteins into the extracellular milieu. A special class of PGHs contains so-called ‘cysteine, histidine-dependent amidohydrolase/peptidase’ (CHAP) domains. In the present study, we profiled the roles of 11 CHAP PGHs encoded by the core genome of <em>S. aureus</em> USA300 LAC. Mutant strains lacking individual CHAP PGHs were analysed for growth, cell morphology, autolysis, and invasion and replication inside human lung epithelial cells. The results show that several investigated CHAP PGHs contribute to different extents to extracellular and intracellular growth and replication of <em>S. aureus</em>, septation of dividing cells, daughter cell separation once the division process is completed, autolysis and biofilm formation. In particular, the CHAP PGHs Sle1 and SAUSA300_2253 control intracellular staphylococcal replication and the resistance to β-lactam antibiotics like oxacillin. This makes the <em>S. aureus</em> PGHs in general, and the Sle1 and SAUSA300_2253 proteins in particular, attractive targets for future prophylactic or therapeutic anti-staphylococcal interventions. Alternatively, these cell surface-exposed enzymes, or particular domains of these enzymes, could be applied in innovative anti-staphylococcal therapies.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000365/pdfft?md5=262fbb700c3027a2b0c8467a74f603f3&pid=1-s2.0-S1438422124000365-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141979142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical characteristics of community-onset Clostridioides difficile infections at a tertiary hospital in mainland China: A fourteen-year (2010–2023) retrospective study","authors":"","doi":"10.1016/j.ijmm.2024.151631","DOIUrl":"10.1016/j.ijmm.2024.151631","url":null,"abstract":"<div><h3>Background</h3><p><em>Clostridioides difficile</em> infection (CDI) is an increasingly common disease in healthcare facilities and community settings. However, there are limited reports of community-onset CDI (CO-CDI) in China.</p></div><div><h3>Methods</h3><p>We collected diarrheal stool samples from 3885 patients who went to outpatient department or emergency department in a tertiary hospital in China during 2010–2023, analyzed the correlation between patients’ basic information and the detection rate of CDI. Besides, all stool samples from 3885 outpatients included were tested by culturing. Moreover, we randomly selected 89 patients’ stools during the 14 years and isolated 126 <em>C. difficile</em> strains from them. The presence of toxin genes (<em>tcdA</em>, <em>tcdB</em>, <em>cdtA</em>, and <em>cdtB</em>) were confirmed by PCR. Toxigenic strains were typed using multilocus sequence typing (MLST). Susceptibility to 9 antimicrobials was evaluated using the E-test.</p></div><div><h3>Results</h3><p>528 of 3885 patients (13.6 %) with diarrhea were finally diagnosed as CDI. The median age of patients included was 51 years (6 months-95 years), while the median of patients with CDI was older than patients with negative results [55.5 years (6 months-93 years) <em>vs.</em> 50 years (9 months −95 years), <em>p</em> &lt; 0.001]. In winter, patients with diarrhea might be more likely to have CDI. The detection rate of CDI of patients in emergency department was much higher than those in other outpatients (20.7 % <em>vs.</em> 12.4 %, <em>p</em> &lt; 0.001), and did differ from each outpatient departments (<em>p</em> &lt; 0.05). There were 95 isolated strains detected as toxigenic <em>C. difficile</em>. Among these strains, 82 (86.3 %) had the <em>tcdA</em> and <em>tcdB</em> genes (A+B+) and 5 of these 82 strains were positive for the binary toxin genes (<em>cdtA</em> and <em>cdtB</em>) (A+B+CDT+). There were 15 different sequence types (STs) by multilocus sequence typing (MLST), while the most ST was ST-54 (23.2 %). ST types composition was relatively stable over the time span of this study. Some strains had high resistance to ciprofloxacin, clindamycin, and erythromycin. Twenty-three isolates (24.2 %) were multidrug-resistant.</p></div><div><h3>Conclusions</h3><p>Outpatients with CDI were common among patients having diarrhea during this period in our hospital. Elderly patients and patients went to emergency department may be susceptible to CDI. Based on MLST, the result revealed that the <em>C. difficile</em> isolates had high genetic diversity and maintained stability in this period. All isolates were susceptible to metronidazole and vancomycin, and nearly one quarter of all isolates had multidrug resistance.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000353/pdfft?md5=3cae71e5cd569816143cb38e32858684&pid=1-s2.0-S1438422124000353-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and characterization of Staphylococcus argenteus from Indonesia","authors":"","doi":"10.1016/j.ijmm.2024.151629","DOIUrl":"10.1016/j.ijmm.2024.151629","url":null,"abstract":"<div><h3>Background</h3><p>In 2015, <em>Staphylococcus argenteus</em> was reported for the first time as a novel species of the <em>Staphylococcus aureus</em> complex. While <em>S. argenteus</em> has been found in many countries, its presence in Indonesia has not been reported yet. Our aim is to confirm <em>S. argenteus</em> presence in Indonesia, describe its characteristics and analyze its genomic diversity.</p></div><div><h3>Methods</h3><p>The <em>S. aureus</em> isolates used in this study were collected from patients with skin and soft tissue infections in Indonesia, between July 2009 to February 2010. Randomly selected isolates were recultured from −80 C° stocks and analyzed using matrix-assisted laser desorption/ionization – time of flight (MALDI-TOF). Isolates identified as <em>S. argenteus</em>, <em>S. roterodami</em>, or <em>S. schweitzeri</em> and <em>S. aureus</em> with a low score in the MALDI-TOF analysis were analyzed by a real-time PCR targeting the <em>nucA</em> gene able to identify true <em>S. argenteus</em>. Isolates identified as <em>S. argenteus</em> were further characterized by whole genome sequencing. Vitek®2 (bioMérieux) was used for antimicrobial susceptibility testing.</p></div><div><h3>Results</h3><p>Fifteen isolates were identified as <em>S. argenteus</em>, with the majority belonging to ST2250. Two pairs of isolates proved to be identical by core genome multilocus sequence typing analysis. Most isolates were susceptible to all antibiotics tested, except for seven isolates (46.7 %) that were resistant to benzylpenicillin, and one isolate was resistant to tetracycline (6.7 %). The presence of resistance genes <em>blaZ</em> and <em>tet(45)</em> correlated with these findings. Notably, the <em>sey</em> enterotoxin gene was prevalent in 80 % of the isolates. Other virulence factor genes were less prevalent. Plasmid replicon types in <em>S. argenteus</em> were also known to <em>S. aureus</em>.</p></div><div><h3>Conclusion</h3><p>Our study reveals the occurrence of <em>S. argenteus</em> in Indonesia. The diversity within Indonesian <em>S. argenteus</em> matches the global diversity of <em>S. argenteus.</em> Identical isolates between patients indicate potential transmission events. A lower prevalence of a broad panel of virulence factors suggests that <em>S. argenteus</em> is less virulent than <em>S. aureus.</em></p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S143842212400033X/pdfft?md5=0e23551bcad6c03be6d39eb0b78ca47a&pid=1-s2.0-S143842212400033X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141762321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time application of ITS and D1-D3 nanopore amplicon metagenomic sequencing in fungal infections: Enhancing fungal infection diagnostics","authors":"","doi":"10.1016/j.ijmm.2024.151630","DOIUrl":"10.1016/j.ijmm.2024.151630","url":null,"abstract":"<div><p>While fungal infections cause considerable morbidity and mortality, the performance of the current diagnostic tests for fungal infection is low. Even though fungal metagenomics or targeted next-generation sequencing have been investigated for various clinical samples, the real-time clinical utility of these methods still needs to be elucidated. In this study, we used <em>internal transcribed spacer</em> (<em>ITS</em>) and <em>D1-D3</em> ribosomal DNA nanopore amplicon metagenomic sequencing to assess its utility in patients with fungal infections. Eighty-four samples from seventy-three patients were included and categorized into ‘Fungal infection,’ ‘Fungal colonization,’ and ‘Fungal contamination’ groups based on the judgement of infectious disease specialists. In the ‘Fungal infection’ group, forty-seven initial samples were obtained from forty-seven patients. Three fungal cases detected not by the sequencing but by conventional fungal assays were excluded from the analysis. In the remaining cases, the conventional fungal assay-negative/sequencing-positive group (n=11) and conventional fungal assay-positive/sequencing-positive group (n=33) were compared. Non-<em>Candida</em> and non-<em>Aspergillus</em> fungi infections were more frequent in the conventional-negative/sequencing-positive group (p-value = 0.031). We demonstrated the presence of rare human pathogens, such as <em>Trichosporon asahii</em> and <em>Phycomyces blakesleeanus</em>. In the ‘Fungal infection’ group and ‘Fungal colonization’ group, sequencing was faster than culturing (mean difference = 4.92 days, p-value &lt; 0.001/ mean difference = 4.67, p-value &lt;0.001). Compared to the conventional diagnostic methods including culture, nanopore amplicon sequencing showed a shorter turnaround time and a higher detection rate for uncommon fungal pathogens.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000341/pdfft?md5=c8f82b8db17e2d758359b6a89455570a&pid=1-s2.0-S1438422124000341-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enteroaggregative Escherichia coli: Frequent, yet underdiagnosed pathotype among E. coli O111 strains isolated from children with gastrointestinal disorders in the Czech Republic","authors":"Klára Schlosserová ,&nbsp;Ondřej Daniel ,&nbsp;Klára Labská ,&nbsp;Vladislav Jakubů ,&nbsp;Tereza Stárková ,&nbsp;Jan Bílý ,&nbsp;Jiří Dresler ,&nbsp;Christina Lang ,&nbsp;Angelika Fruth ,&nbsp;Antje Flieger ,&nbsp;Helena Žemličková ,&nbsp;Martina Bielaszewska ,&nbsp;Monika Havlíčková","doi":"10.1016/j.ijmm.2024.151628","DOIUrl":"10.1016/j.ijmm.2024.151628","url":null,"abstract":"<div><p>Enteroaggregative <em>Escherichia coli</em> (EAEC) strains including those of serogroup O111 are important causes of diarrhea in children. In the Czech Republic, no information is available on the etiological role of EAEC in pediatric diarrhea due to the lack of their targeted surveillance. To fill this gap, we determined the proportion of EAEC among <em>E. coli</em> O111 isolates from children with gastrointestinal disorders ≤ 2 years of age submitted to the National Reference Laboratory for <em>E. coli</em> and Shigella during 2013–2022. EAEC accounted for 177 of 384 (46.1 %) <em>E. coli</em> O111 isolates, being the second most frequent <em>E. coli</em> O111 pathotype. Most of them (75.7 %) were typical EAEC that carried <em>aggR</em>, usually with <em>aaiC</em> and <em>aatA</em> marker genes; the remaining 24.3 % were atypical EAEC that lacked <em>aggR</em> but carried <em>aaiC</em> and/or <em>aatA</em>. Whole genome sequencing of 11 typical and two atypical EAEC O111 strains demonstrated differences in serotypes, sequence types (ST), virulence gene profiles, and the core genomes between these two groups. Typical EAEC O111:H21/ST40 strains resembled by their virulence profiles including the presence of the aggregative adherence fimbriae V (AAF/V)-encoding cluster to such strains from other countries and clustered with them in the core genome multilocus sequence typing (cgMLST). Atypical EAEC O111:H12/ST10 strains lacked virulence genes of typical EAEC and differed from them in cgMLST. All tested EAEC O111 strains displayed stacked-brick aggregative adherence to human intestinal epithelial cells. The AAF/V-encoding cluster was located on a plasmid of 95,749 bp or 93,286 bp (pAA_O111) which also carried <em>aggR</em>, <em>aap</em>, <em>aar</em>, <em>sepA</em>, and <em>aat</em> cluster. EAEC O111 strains were resistant to antibiotics, in particular to aminopenicillins and cephalosporins; 88.3 % produced AmpC β-lactamase, and 4.1 % extended spectrum β-lactamase. We conclude that EAEC are frequent among <em>E. coli</em> O111 strains isolated from children with gastrointestinal disorders in the Czech Republic. To reliably assess the etiological role of EAEC in pediatric diarrhea, a serotype-independent, PCR-based pathotype surveillance system needs to be implemented in the future.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000328/pdfft?md5=bba7af0e324afe171ce3ff34b4303305&pid=1-s2.0-S1438422124000328-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141472120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncovering the mechanisms of host mitochondrial cardiolipin release in syphilis: Insights from human microvascular endothelial cells","authors":"Xi Luo ,&nbsp;Xiaoyuan Xie ,&nbsp;Litian Zhang ,&nbsp;Yanqiang Shi ,&nbsp;Bo Fu ,&nbsp;Liyan Yuan ,&nbsp;Yan Zhang ,&nbsp;Yinbo Jiang ,&nbsp;Wujian Ke ,&nbsp;Bin Yang","doi":"10.1016/j.ijmm.2024.151627","DOIUrl":"https://doi.org/10.1016/j.ijmm.2024.151627","url":null,"abstract":"<div><p>The release of host mitochondrial cardiolipin is believed to be the main factor that contributes to the production of anti-cardiolipin antibodies in syphilis. However, the precise mechanism by which mitochondria release cardiolipin in this context remains elusive. This study aimed to elucidate the mechanisms underlying mitochondrial cardiolipin release in syphilis. We conducted a cardiolipin quantitative assay and immunofluorescence analysis to detect mitochondrial cardiolipin release in human microvascular endothelial cells (HMEC-1), with and without <em>Treponema pallidum</em> (<em>Tp</em>) infection. Furthermore, we explored apoptosis, a key mechanism for mitochondrial cardiolipin release. The potential mediator molecules were then analyzed through RNA-sequence and subsequently validated using <em>in vitro</em> knockout techniques mediated by CRISPR-Cas9 and pathway-specific inhibitors. Our findings confirm that live-<em>Tp</em> is capable of initiating the release of mitochondrial cardiolipin, whereas inactivated-<em>Tp</em> does not exhibit this capability. Additionally, apoptosis detection further supports the notion that the release of mitochondrial cardiolipin occurs independently of apoptosis. The RNA-sequencing results indicated that microtubule-associated protein2 (MAP2), an axonogenesis and dendrite development gene, was up-regulated in HMEC-1 treated with <em>Tp,</em> which was further confirmed in syphilitic lesions by immunofluorescence. Notably, genetic knockout of MAP2 inhibited <em>Tp</em>-induced mitochondrial cardiolipin release in HMEC-1. Mechanically, <em>Tp</em>-infection regulated MAP2 expression via the MEK-ERK-HES1 pathway, and MEK/ERK phosphorylation inhibitors effectively block <em>Tp</em>-induced mitochondrial cardiolipin release. This study demonstrated that the infection of live-<em>Tp</em> enhanced the expression of MAP2 via the MEK-ERK-HES1 pathway, thereby contributing to our understanding of the role of anti-cardiolipin antibodies in the diagnosis of syphilis.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000316/pdfft?md5=a8a3f0c394c310f7a36841decd3ec00a&pid=1-s2.0-S1438422124000316-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141439091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of mutations in the ftsI gene leading to amino acid substitutions in PBP3 in Haemophilus influenzae strains under the selective pressure of ampicillin and cefuroxime","authors":"Vladislav Jakubu ,&nbsp;Iveta Vrbova ,&nbsp;Ibrahim Bitar ,&nbsp;Marketa Cechova ,&nbsp;Lucia Malisova ,&nbsp;Helena Zemlickova","doi":"10.1016/j.ijmm.2024.151626","DOIUrl":"https://doi.org/10.1016/j.ijmm.2024.151626","url":null,"abstract":"<div><h3>Background</h3><p>Aminopenicillins are recommended agents for non-invasive <em>Haemophilus influenzae</em> infections. One of the mechanisms of resistance to β-lactams is the alteration of the transpeptidase region of penicillin binding protein 3 (PBP3) which is caused by mutations in the <em>ftsI</em> gene. It was shown that exposure to beta-lactams has a stimulating effect on increase of prevalence of <em>H. influenzae</em> strains with the non-enzymatic mechanism of resistance.</p></div><div><h3>Objectives</h3><p>The aim of our study was to compare the mutational potential of ampicillin and cefuroxime in <em>H. influenzae</em> strains, determination of minimum inhibitory concentration and the evolution of mutations over time, focusing on amino acid substitutions in PBP3.</p></div><div><h3>Methods</h3><p>30 days of serial passaging of strains in liquid broth containing increasing concentrations of ampicillin or cefuroxime was followed by whole-genome sequencing.</p></div><div><h3>Results</h3><p>On average, cefuroxime increased the minimum inhibitory concentration more than ampicillin. The minimum inhibitory concentration was increased by a maximum of 32 fold. Substitutions in the PBP3 started to appear after 15 days of passaging. In PBP3, cefuroxime caused different substitutions than ampicillin.</p></div><div><h3>Conclusions</h3><p>Our experiment observed differences in mutation selection by ampicillin and cefuroxime. Selection pressure of antibiotics in vitro generated substitutions that do not occur in clinical strains in the Czech Republic.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000304/pdfft?md5=86397ef66bdbd21e557fa9a191521b10&pid=1-s2.0-S1438422124000304-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141484439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Past and present seroprevalence and disease burden estimates of Toxoplasma gondii infections in Germany: An appreciation of the role of serodiagnostics” [Int. J. Med. Microbiol. 313 (2023) 151592]","authors":"Frank Seeber","doi":"10.1016/j.ijmm.2024.151618","DOIUrl":"10.1016/j.ijmm.2024.151618","url":null,"abstract":"","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000225/pdfft?md5=07fd91261f1c7344ee30e89ead1044ca&pid=1-s2.0-S1438422124000225-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140764894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An induced mutation of ABC-transporter component VraF(K84E) contributes to vancomycin resistance and virulence in Staphylococcus aureus strain MW2","authors":"Ruobing Cao ,&nbsp;Huimin Su ,&nbsp;Zichun Wei ,&nbsp;Zhien He ,&nbsp;Ting Pan ,&nbsp;Yujie Li ,&nbsp;Baolin Sun","doi":"10.1016/j.ijmm.2024.151624","DOIUrl":"https://doi.org/10.1016/j.ijmm.2024.151624","url":null,"abstract":"<div><p><em>Staphylococcus aureus</em> is a notorious pathogen responsible for various severe diseases. Due to the emergence of drug-resistant strains, the prevention and treatment of <em>S. aureus</em> infections have become increasingly challenging. Vancomycin is considered to be one of the last-resort drugs for treating most methicillin-resistant <em>S. aureus</em> (MRSA), so it is of great significance to further reveal the mechanism of vancomycin resistance. VraFG is one of the few important ABC (ATP-binding cassette) transporters in <em>S. aureus</em> that can form TCS (two-component systems)/ABC transporter modules. ABC transporters can couple the energy released from ATP hydrolysis to translocate solutes across the cell membrane. In this study, we obtained a strain with decreased vancomycin susceptibility after serial passaging and selection. Subsequently, whole-genome sequencing was performed on this laboratory-derived strain MWA2 and a novel single point mutation was discovered in <em>vraF</em> gene, leading to decreased sensitivity to vancomycin and daptomycin. Furthermore, the mutation reduces autolysis of <em>S. aureus</em> and downregulates the expression of <em>lytM</em>, <em>isaA</em>, and <em>atlA</em>. Additionally, we observed that the mutant has a less net negative surface charge than wild-type strain. We also noted an increase in the expression of the <em>dlt</em> operon and <em>mprF</em> gene, which are associated with cell surface charge and serve to hinder the binding of cationic peptides by promoting electrostatic repulsion. Moreover, this mutation has been shown to enhance hemolytic activity, expand subcutaneous abscesses, reflecting an increased virulence. This study confirms the impact of a point mutation of VraF on <em>S. aureus</em> antibiotic resistance and virulence, contributing to a broader understanding of ABC transporter function and providing new targets for treating <em>S. aureus</em> infections.</p></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1438422124000286/pdfft?md5=e052303279a99f3f97dbf815ad0bceeb&pid=1-s2.0-S1438422124000286-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141249384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}