International Journal of Medical Microbiology最新文献

{"title":"Emergence of novel sublineages of Mycobacterium tuberculosis in Pakistan","authors":"Muhammad Tahir Khan ,&nbsp;Chendi Zhu ,&nbsp;Arwa Omar Al Khatib ,&nbsp;Dalal Sulaiman Alshaya ,&nbsp;Ahmed A. Al-Qahtani ,&nbsp;Irfan Ahmad ,&nbsp;Taane G. Clark","doi":"10.1016/j.ijmm.2025.151684","DOIUrl":"10.1016/j.ijmm.2025.151684","url":null,"abstract":"<div><h3>Introduction</h3><div>Understanding the distribution and prevalence of different <em>M. tuberculosis</em> lineages can help public health authorities and researchers track the spread of tuberculosis (TB). Some lineages are thought to be more virulent, transmissible, and prone to drug resistance. Here, we sought to find the major lineages and sublineages of <em>M. tuberculosis</em> circulating in Pakistan. Methods: A total of 396 whole-genome sequencing datasets were retrieved from NCBI and TB research centers. Results: In the current study, only four lineages and 21 sublineages have been detected in 396 genomic isolates in which lineages 3 (n = 274/396, 69.19 %) was the predominant, followed by lineage 4 (77/396, 19.4 %), lineage 2 (31/396, 7.8 %), and lineage 1 (14/396, 3.5 %). Lineage 3 was the most common, in which sublineage 3.1.1 (n = 254/274, 93.79 %) was dominant, followed by sublineage 3.1.2.1 (n = 11/274, 4 %) and 3.1.2 (n = 8/274, 2.9 %). 8 sublineages are likely reported for the first time in Pakistan based on current genomic surveillance including sublineage 3.1.2.1 (n = 11/274, 4 %). There were 14 sublineages in lineage 4, of which sublineage L4.5 (23/77, 29.8 %) was the most common, followed by sublineage 4.9 (22/77, 28.5 %). Conclusion: Collectively, these observations highlight Lineage 3’s ability to acquire first-line drug resistance continued transmission. Its predominance in the current study highlights the urgent need for lineage-specific diagnostics, enhanced drug susceptibility testing and tailored therapeutic regimens. The detection of diverse Mtb sublineages, including L3.1.2.1 and various sublineages of L4 (e.g., 4.1.1.1, 4.1.2.1, 4.3.4.2, and 4.6.2.2), signifies advancement in understanding the genetic landscape of TB in the region.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151684"},"PeriodicalIF":3.6,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145551654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Virulome and genome-wide association study of vancomycin-resistant Enterococcus faecium from bloodstream infections versus colonization isolates","authors":"Christian W. Böing ,&nbsp;Julia S. Schneider ,&nbsp;Neele J. Froböse ,&nbsp;Annette Jurke ,&nbsp;Stefanie Kampmeier ,&nbsp;Alexander Mellmann","doi":"10.1016/j.ijmm.2025.151683","DOIUrl":"10.1016/j.ijmm.2025.151683","url":null,"abstract":"<div><h3>Introduction</h3><div>Vancomycin-resistant <em>Enterococcus faecium</em> (VREfm) are multidrug-resistant pathogens that cause severe nosocomial infections. The knowledge of virulence profiles of VREfm for the development of invasive infections is still limited. The aim of this study was to analyse gene profiles and genetic variants of VREfm and their association with the development of VREfm bloodstream infections (VRE-BSI).</div></div><div><h3>Methods</h3><div>One-hundred twenty randomly selected VRE-BSI isolates from a state-wide surveillance study in the German state of North Rhine-Westphalia were included in the analysis and matched with one-hundred twenty VREfm colonization (VRE-COL) isolates from a tertiary hospital in North Rhine-Westphalia. All isolates were subjected to whole genome sequencing (WGS) and analysed for the presence or absence of known or putative virulence genes of <em>E. faecium</em>. A genome-wide association study (GWAS) approach was conducted to identify potential associations of genes and genetic variants with the development of VRE-BSI.</div></div><div><h3>Results</h3><div>The multilocus sequence typing (MLST) sequence types (ST) ST80 and ST117 were the most prevalent STs among VRE-BSI and VRE-COL isolates (ST80: 133 [55 %]; ST117: 98 [41 %]). ST80 was significantly more prevalent in VRE-BSI isolates compared to VRE-COL isolates (75 [63 %] vs. 58 [48 %], p = 0.027). Only <em>fms21</em> (<em>pilA</em>), a gene of pili gene cluster 1 (PCG-1), coding for a cell-wall-anchored protein involved in adhesive processes, was significantly more prevalent in the VRE-BSI group. GWAS identified no associations of genes or variants with VRE-BSI.</div></div><div><h3>Conclusion</h3><div>Using comparative genomics and GWAS, we could not identify a distinct virulence profile for the development of VRE-BSI.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151683"},"PeriodicalIF":3.6,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145558397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A large outbreak investigation of Legionnaires’ disease associated with a public bath facility in Hiroshima, Japan, using PFGE, SBT, MLVA, and whole-genome sequencing","authors":"Takahiro Hiratsuka ,&nbsp;Noriko Nakanishi ,&nbsp;Hiroko Akita ,&nbsp;Kanako Masuda ,&nbsp;Shoko Komatsu ,&nbsp;Ryohei Nomoto ,&nbsp;Junko Amemura-Maekawa","doi":"10.1016/j.ijmm.2025.151680","DOIUrl":"10.1016/j.ijmm.2025.151680","url":null,"abstract":"<div><div>In 2017, a large outbreak of Legionnaires' disease, involving 58 patients, occurred in a public bath facility in Hiroshima Prefecture, Japan. We analyzed 94 <em>Legionella pneumophila</em> strains isolated from patients and the public bath facility using molecular typing methods, including Pulsed-Field Gel Electrophoresis, sequence-based typing, multi-locus variable number tandem repeat analysis, and Whole-Genome Sequencing (WGS). Genotypes obtained using these molecular epidemiological typing methods were highly correlated with each other. <em>L. pneumophila</em> strains of various genotypes were isolated from the public bath facility, of which only ST2398 and ST2399 were isolated from patients. ST2398 and ST2399, isolated from patients, bath water, and swabs, derived from one common circulating system at the bath facility out of seven were found to be novel genotypes and a highly clonal genetic lineage by single nucleotide variant (SNV) analysis based on WGS. The result of haplotype network analysis based on SNVs showed that ST2398 and ST2399 differed only approximately 30–42 SNVs, and some environmental strains that differed by only 0–3 SNVs from patient strains were isolated. These results demonstrated that this outbreak was caused by <em>L. pneumophila</em> assigned to the ST2398 and ST2399 clades. We found that at least three patients were co-infected with different clusters of <em>L. pneumophila</em> serogroup 1. Our results show that several strains must be isolated from a single sample to consider the accumulation of mutations in water and co-infection when investigating outbreaks.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151680"},"PeriodicalIF":3.6,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential expression profile of streptolysin S in the covR and covS mutants of group A Streptococcus is a mediator of keratinocyte death and aggressive local infection","authors":"Yong-An Shi ,&nbsp;Hang Kim Nguyen ,&nbsp;Pei-Jane Tsai ,&nbsp;Cheng-Hsun Chiu ,&nbsp;Chuan Chiang-Ni","doi":"10.1016/j.ijmm.2025.151682","DOIUrl":"10.1016/j.ijmm.2025.151682","url":null,"abstract":"<div><div>Group A <em>Streptococcus</em> (GAS) isolates with spontaneous mutations in <em>covR</em> and <em>covS</em> are frequently identified in patients with necrotizing fasciitis and toxic shock syndrome. CovR/CovS is a two-component regulator system, and the phosphorylation of CovR is solely modulated by CovS. Nonetheless, the phenotype of the ∆<em>covS</em> mutant and the ∆<em>covR</em> mutant is not entirely identical. It has been shown that the expression of SpeB protease is only detected in the ∆<em>covR</em> mutant, and the ∆<em>covR</em> mutant causes more severe local lesions than the ∆<em>covS</em> mutant in the mouse infection model. SpeB-mediated gasdermin A cleavage triggers keratinocyte death, resulting in sizeable lesion size but preventing invasive skin infection by GAS. This study, therefore, elucidated whether SpeB is a key factor related to trigger keratinocyte death after the ∆<em>covR</em> mutant infection. Although the ∆<em>covR</em> mutant caused more keratinocyte deaths than the ∆<em>covS</em> mutant, this difference was not contributed by SpeB but mediated by streptolysin S (SLS). Moreover, SLS in the ∆<em>covR</em> mutant contributed to increased macrophage cell death and elevated IL-1β levels. Similar to the SpeB expression profile, SLS was upregulated in the ∆<em>covR</em> mutant but repressed in the ∆<em>covS</em> mutant. In a mouse subcutaneous infection model, the SLS-deficient ∆<em>covR</em> mutant exhibited reduced lesion size and mortality compared to the ∆<em>covR</em> mutant, suggesting that SLS repression does not contribute to GAS immune evasion or invasive skin infection. This finding may help explain the differential presentations after ∆<em>covR</em> mutant and ∆<em>covS</em> mutant infection and why clinical GAS isolates more frequently harbor spontaneous mutations in <em>covS</em> rather than in <em>covR</em>.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151682"},"PeriodicalIF":3.6,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Complete genome and comparative genomic analysis of cefpodoxime resistant Pantoea septica strain GABEPS69 isolated from saliva of a patient diagnosed with treatment resistant schizophrenia","authors":"Francesca McDonagh ,&nbsp;Aneta Kovarova ,&nbsp;Anna Tumeo ,&nbsp;Andy O’Connor ,&nbsp;Niamh McEvoy ,&nbsp;Aneesa Mangalam Lonappan ,&nbsp;Kasthuri Venkateswaran ,&nbsp;Elaine K. Murray ,&nbsp;Brian Hallahan ,&nbsp;Georgios Miliotis","doi":"10.1016/j.ijmm.2025.151681","DOIUrl":"10.1016/j.ijmm.2025.151681","url":null,"abstract":"<div><h3>Objectives</h3><div>This study aims to generate the first complete genome of <em>Pantoea septica</em> and provide a thorough genomic characterisation of this under-documented species. The study seeks to enhance understanding of <em>P. septica,</em> clarifying features relevant to opportunistic infection in vulnerable cohorts<em>.</em></div></div><div><h3>Methods</h3><div><em>P. septica</em> GABEPS69 was an opportunistic coloniser isolated from the saliva of a patient prescribed the antipsychotic clozapine, leading to a dysbiotic oral microbiome. A hybrid sequencing approach yielded a closed genome comprising a 4.1 Mb chromosome and six plasmids. Phenotypic susceptibility was determined by disk-diffusion and minimum inhibitory concentration (MIC) assays. Its chromosomal and plasmidic content was bioinformatically analysed alongside all canonical GenBank available <em>P. septica</em> genomes and the type strains of taxonomic neighbours <em>Pantoea piersonii</em> and \"<em>Pantoea latae</em>\", with focus on virulence-factors (VFs), antimicrobial-resistance-genes (ARGs), metal-resistance-genes (MRGs) and biosynthetic gene clusters.</div></div><div><h3>Results</h3><div>GABEPS69 exhibited a narrow resistance spectrum, displaying resistance to the third-generation cephalosporin cefpodoxime. Plasmid pGABEPS69_1 harboured an aerobactin pathogenicity island homologue; a locus implicated in enhanced virulence, that was also identified across most other <em>P. septica</em> genomes and in the closely related human-pathogen <em>Pantoea piersonii</em>. A conserved chromosomal class-A β-lactamase homologue was also identified. Additionally, a universal presence of bioactive thiopeptide biosynthetic-gene-clusters was observed in <em>P. septica</em> genomes, suggesting a potential role in microbiome modulation.</div></div><div><h3>Conclusion</h3><div>This study presents a first complete genome of <em>P. septica</em>, revealing its genomic architecture, resistance, and virulence potential. Detailed plasmid analysis and comparative genomics enhance our understanding of the species clinical relevance and microbiome-modulating capacity. These findings motivate surveillance of transient oral microbiota in at-risk populations, including patients receiving clozapine.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151681"},"PeriodicalIF":3.6,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145453578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The development of an Actinomadura madurae grain model in Galleria mellonella larvae","authors":"Shereen O. Abd Algaffar ,&nbsp;Annelies Verbon ,&nbsp;Kimberly Eadie ,&nbsp;Deborah Horst-Kreft ,&nbsp;Sami A. Khalid ,&nbsp;Wendy W.J. van de Sande","doi":"10.1016/j.ijmm.2025.151679","DOIUrl":"10.1016/j.ijmm.2025.151679","url":null,"abstract":"<div><div>Mycetoma is a neglected tropical disease characterized by large tumorous lesions. It can be caused by fungi (eumycetoma) or bacteria (actinomycetoma). The hallmark of mycetoma is the formation of grains by the causative agent. Grains can only be formed <em>in vivo;</em> therefore, <em>in vivo</em> models are crucial to studying mycetoma<em>. In vivo,</em> grain models have been developed in the invertebrate <em>Galleria mellonella</em> for eumycetoma, but not for actinomycetoma. Here, we aimed to develop the first actinomycetoma grain model in <em>G. mellonella</em> larvae. <em>Actinomadura madurae</em> strains DSM43236 and DSM44005 were used to infect <em>G. mellonella</em> larvae. Larval survival was monitored over 10 days. Grain formation was studied histologically and compared to grains in human tissues. The efficacy of trimethoprim-sulfamethoxazole and amikacin, the current standard treatment for actinomycetoma, was determined. <em>A. madurae</em> infection decreased the survival of <em>G. mellonella</em> larvae in a concentration-dependent manner. Grains were formed within 24 h post-infection. After 72 h these grains became melanised. No significantly enhanced survival was noted with trimethoprim-sulfamethoxazole, amikacin, or a combination thereof. In this model, the melanised <em>A. madurae</em> grains did differ from human grains, most likely due to the immune system of <em>G. mellonella</em>. The lack of therapeutic efficacy could be caused by this melanin or the fact that <em>A. madurae</em> grains, in general, are less susceptible to these drugs. More research will be needed to address this question.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151679"},"PeriodicalIF":3.6,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145318953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Culture-positive COVID-19-associated pulmonary aspergillosis (CAPA) in Germany","authors":"Leonie H. Aldejohann ,&nbsp;Joerg Steinmann ,&nbsp;Tamara Ruegamer ,&nbsp;Ronny Martin ,&nbsp;Nadja Thielemann ,&nbsp;Grit Walther ,&nbsp;Oliver Kurzai ,&nbsp;Alexander M. Aldejohann","doi":"10.1016/j.ijmm.2025.151676","DOIUrl":"10.1016/j.ijmm.2025.151676","url":null,"abstract":"<div><h3>Background</h3><div>COVID-19-associated-pulmonary-aspergillosis (CAPA) is a severe superinfection mostly affecting critically ill COVID-19 patients. Early diagnosis and clinical management of CAPA remain major clinical challenges.</div><div>Here, we evaluated different approaches to classify culture-positive CAPA at its peak season, assessed incidence and mortality, identified risk factors and analysed clinical and laboratory CAPA-management of three German tertiary care hospitals.</div></div><div><h3>Methods</h3><div>A retrospective multi-center analysis was performed. Inclusion criteria were SARS-CoV-2-positivity, <em>Aspergillus</em>-culture-positivity of lower respiratory tract specimen and ARDS. Cases were primarily classified according to ECMM/ISHAM-criteria. Species-ID was confirmed by each center. Susceptibility was assessed by EUCAST-microdilution or VIPcheck-screening. Statistical analysis revealed mortality affecting factors.</div></div><div><h3>Results</h3><div>95 culture-positive CAPA cases were classified as possible (36/95) or probable (59/95) by ECMM/ISHAM; 54 probable cases matched 2 or 3 additional classifications. Incidence rates were higher in ICU (2020/21: 1.56 %/2.13 % non-ICU vs. 5.14 %/6.77 % ICU). <em>A. fumigatus</em> was the most abundant species (93 %; (88/95)). Most patients received steroids to treat COVID-19-ARDS and required respiratory support (steroids: 71 % (67/95); intubated patients 52 % (49/95); ECMO (48 % (46/95)). Retrospective evaluation showed adherence to ECMM/ISHAM antifungal therapy guideline in 71 % (67/95). Case fatality rate was 60 % (57/95). A significant association between GM indices &gt; 3 in respiratory fluid or nicotine abuse (p = 0.035 FE, OR=0.252, 95 % CI=0.066–0.986) and mortality was observed in univariate analysis. Convalescent plasma therapy was significantly associated with mortality reduction in uni- and multivariate analysis (p = 0.020).</div></div><div><h3>Conclusion</h3><div>Our data reveal regional differences in prevalence, diagnosis, and treatment of culture-positive CAPA in Germany. We could identify new factors affecting survival or mortality.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151676"},"PeriodicalIF":3.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of HBV infection on gut microbiota using Chinese woodchuck model with woodchuck hepatitis virus (WHV) infection","authors":"Deng Hui ,&nbsp;Zhu Bin ,&nbsp;Zhang Shiyu ,&nbsp;Zhang Bin ,&nbsp;Dilihumar Zaire ,&nbsp;Gao Ruihan ,&nbsp;Liu Shuting ,&nbsp;Zhou Xin ,&nbsp;Zhou Shunchang ,&nbsp;Xiong Jian ,&nbsp;Yang Xuecheng ,&nbsp;Feng Xuemei ,&nbsp;Lu Yinping ,&nbsp;Zheng Xin ,&nbsp;Wang Baoju","doi":"10.1016/j.ijmm.2025.151675","DOIUrl":"10.1016/j.ijmm.2025.151675","url":null,"abstract":"<div><div>Hepatitis B virus (HBV) infection seems to be related to gut microbiota. This study aims to explore the effects of HBV infection on gut microbiota and possible immunological mechanisms using the Chinese woodchuck model. Nine adult woodchucks were randomly divided into Cyclosporine A (CsA) or Control group. Animals were orally treated with CsA and saline for 2 weeks before WHV inoculation, and continued until 8 weeks after that. Blood CsA concentrations were tested at 2 weeks after administration and before discontinuation. Quantitative PCR was used to detect serum WHV DNA. Flow cytometry was used to detect T cell immune response. Feces were collected for 16S rRNA sequencing. The result shows CsA oral administration can reach effective blood drug concentration in woodchucks and successfully prolong WHV replication. After 2 weeks of oral treatment, there was no significant difference in the gut microbiota between the two groups. At the clearance period of serum WHV, the relative abundance of Prevotella and Prevotella genera in the phylum Bacteroidetes significantly increased, while the relative abundance of Firmicutes significantly decreased. Meanwhile, the CD107a degranulation of CD4-T cells in peripheral blood showed a decreasing trend, while there was no significant difference in the frequency of PD-1+ CD4-T cells. In Conclusion, oral administration of CsA can significantly prolong the replication time of WHV in Chinese woodchucks. The gut microbiota of Chinese woodchuck undergoes significant changes during serum WHV clearance, which implies the Chinese woodchuck model can be used to study the interaction between HBV infection and gut microbiota.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151675"},"PeriodicalIF":3.6,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization and spectrum characterization of the antibacterial activity of lugdunin","authors":"Cheng-Yen Kao ,&nbsp;Nevia Longjam ,&nbsp;Jazon Harl Hidrosollo ,&nbsp;Lee-Chung Lin ,&nbsp;Jang-Jih Lu","doi":"10.1016/j.ijmm.2025.151678","DOIUrl":"10.1016/j.ijmm.2025.151678","url":null,"abstract":"<div><div><em>Staphylococcus lugdunensis</em>, an emerging coagulase-negative <em>Staphylococcus</em> (CoNS) pathogen, has garnered increasing interest due to its production of lugdunin, a thiazolidine-containing antimicrobial peptide. However, standardized protocols for directly assessing lugdunin activity produced by <em>S. lugdunensis</em> remain lacking. In this study, we examined the effects of pH and incubation duration on lugdunin activity and evaluated the antibacterial spectrum of lugdunin produced by <em>S. lugdunensis</em> isolates against a panel of gram-positive and gram-negative bacterial strains. The optimal conditions for lugdunin antibacterial activity of isolate CGMH-SL85 were identified as pH 7.5 and a 72-h incubation period. Under the tested conditions, the lugdunin produced by CGMH-SL85 exhibited antimicrobial activity against five gram-positive strains, including <em>Staphylococcus aureus</em> ATCC29213 and <em>Staphylococcus haemolyticus</em> CGMH-SH53, followed by <em>Enterococcus faecium</em> EF029 and EF081–2 and <em>Listeria monocytogenes</em> ATCC10403S. However, no antibacterial activity was observed against any of the 11 tested gram-negative bacterial species. Furthermore, four distinct lugdunin susceptibility phenotypes were observed among 47 lugdunin-nonproducing <em>S. lugdunensis</em> strains (14 sequence type (ST)4, 27 ST27, and 6 ST29 strains), including Type A characterized by large, clear inhibition zones; Type B with smaller, clear zones; Type C displaying halo-like inhibition zones; and Type D showing no detectable activity. Moreover, 20 <em>S. lugdunensis</em> strains (42.6 %) exhibited the Type C phenotype. Notably, all six ST29 strains displayed the Type C phenotype, while the Type A phenotype was observed only among ST27 strains (3 strains). In conclusion, we developed a standardized protocol for evaluating lugdunin activity, using pH 7.5 and a 72-h incubation period, and found that different <em>S. lugdunensis</em> strains exhibited distinct lugdunin susceptibility phenotypes.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151678"},"PeriodicalIF":3.6,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic analyses of enteroinvasive Escherichia coli revealed the circulation of conjugative virulence plasmids and emergence of novel clones","authors":"Kazuhisa Okada ,&nbsp;Warawan Wongboot ,&nbsp;Amonrattana Roobthaisong ,&nbsp;Nonzee Hanchanachai ,&nbsp;Pawinee Doung-ngern ,&nbsp;Pilailuk Akkapaiboon Okada ,&nbsp;Thanee Wongchai ,&nbsp;Witaya Swaddiwudhipong ,&nbsp;Tetsuya Iida ,&nbsp;Shigeyuki Hamada","doi":"10.1016/j.ijmm.2025.151677","DOIUrl":"10.1016/j.ijmm.2025.151677","url":null,"abstract":"<div><div>Enteroinvasive <em>Escherichia coli</em> (EIEC) is a diarrhoeagenic <em>E. coli</em> pathotype that shares key virulence traits with <em>Shigella</em>, including the invasion plasmid (pINV). In Thailand, an outbreak caused by the EIEC serotype O8:H19—the first reported in the country—occurred in 2023, affecting over 150 patients. To elucidate the emergence, clinical relevance, and epidemiological distribution of EIEC in Thailand, we conducted a comprehensive investigation. We isolated and genomically characterised 63 isolates, comprising 28 EIEC (eight serotypes, including O96:H19 from a 2024 outbreak) and 35 <em>Shigella</em> (25 <em>S. sonnei</em> and 10 <em>S. flexneri</em>), along with 85 global reference strains. Comparative genomics revealed that the 2023 and 2024 EIEC outbreak isolates, along with a novel OX18:H25 EIEC lineage, harboured highly similar pINV plasmids with conserved invasion genes and complete conjugation elements. These isolates retained several biochemical traits that were more typical of commensal <em>E. coli</em> than classical EIEC. Limited chromosomal genome reduction—a hallmark of <em>Shigella</em>— was observed, which suggests that these lineages are in an early stage of adaptation toward a pathogenic lifestyle. Phylogenomic analysis showed that OX18:H25 is closely related to livestock-associated <em>E. coli</em>, supporting the hypothesis that pINV was recently acquired via horizontal gene transfer. These findings highlight the active circulation of putatively conjugative virulence plasmids among <em>E. coli</em> populations and the ongoing emergence of novel EIEC clones with epidemic-inducing potential.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"321 ","pages":"Article 151677"},"PeriodicalIF":3.6,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}