International Journal of Medical Microbiology最新文献

{"title":"Validation of ML-algorithms for the prediction of positive urine cultures from flow cytometry routine data in patients with suspected bacteriuria","authors":"Alexander Brenner ,&nbsp;Jutta Esser ,&nbsp;Franziska Schuler ,&nbsp;Julian Varghese ,&nbsp;Frieder Schaumburg","doi":"10.1016/j.ijmm.2025.151652","DOIUrl":"10.1016/j.ijmm.2025.151652","url":null,"abstract":"<div><div>Urine samples are frequently analyzed in microbiology laboratories, but a large proportion of them are culture-negative. The aim of this study was to test whether positive urine cultures can be predicted from routine flow cytometric data. Urine samples (n = 1325) were used for a train dataset (n = 1032) and three independent test datasets (n = 93–100 samples) that were collected three months apart. Predictors from flow cytometry were total counts per µl of bacteria, erythrocytes, yeast-like cells, hyaline casts, crystals, leukocytes, squamous epithelial cells, non-hyaline casts and non-squamous epithelial cells in addition to age, sex and type of urine sample. Labels were positive culture and detection of clinically relevant uropathogens. Three classifiers (decision tree, random forest classifier, CatBoost) were 5-fold cross-validated on the train dataset to select an optimized model with ≥ 95 % sensitivity. The optimized model was trained on the complete train dataset and evaluated on the three independent test sets. In total, 72.5 % (960/1325) samples were culture positive with a predominance of <em>Escherichia coli</em> (n = 295). CatBoost outperformed the other classifiers in terms of balanced accuracy (train data) and was selected as the classifier for predictions. With optimised hyperparameters, the balanced accuracy was 62–74 % for the prediction of a positive culture (test data) and had a sensitivity that was stable over a period of six months (94–96 %, negative predictive value [NPV]: 67–77 %, positive predictive value [PPV]: 78–81 %). For the prediction of uropathogens, the balanced accuracy was 57–63 % with a stable sensitivity (95–100 %, NPV: 83–100 %, PPV: 48–59 %). In conclusion, the ML algorithms showed high sensitivity for detecting positive urine cultures.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151652"},"PeriodicalIF":4.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549155","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":"Comparison of clinical metagenomics with 16S rDNA Sanger sequencing for the bacteriological diagnosis of culture-negative samples","authors":"Camille d’Humières ,&nbsp;Skerdi Haviari ,&nbsp;Marie Petitjean ,&nbsp;Laurène Deconinck ,&nbsp;Signara Gueye ,&nbsp;Nathan Peiffer-Smadja ,&nbsp;Lynda Chalal ,&nbsp;Naima Beldjoudi ,&nbsp;Geoffrey Rossi ,&nbsp;Yann Nguyen ,&nbsp;Charles Burdet ,&nbsp;Ségolène Perrineau ,&nbsp;Diane Le Pluart ,&nbsp;Roza Rahli ,&nbsp;Michael Thy ,&nbsp;Piotr Szychowiak ,&nbsp;Xavier Lescure ,&nbsp;Véronique Leflon-Guibout ,&nbsp;Victoire de Lastours ,&nbsp;Etienne Ruppé","doi":"10.1016/j.ijmm.2025.151650","DOIUrl":"10.1016/j.ijmm.2025.151650","url":null,"abstract":"<div><h3>Background</h3><div>Currently, diagnosis of bacterial infections is based on culture, possibly followed by the amplification and sequencing (Sanger method) of the 16S rDNA - encoding gene when cultures are negative. Clinical metagenomics (CMg), i.e. the sequencing of a sample’s entire nucleic acids, may allow for the identification of bacteria not detected by conventional methods. Here, we tested the performance of CMg compared to 16S rDNA sequencing (Sanger) in 50 patients with suspected bacterial infection but negative cultures.</div></div><div><h3>Methods</h3><div>This is a prospective cohort study. Fifty patients (73 samples) with negative culture and a 16S rDNA sequencing demand (Sanger) were recruited from two sites. On the same samples, CMg (Illumina NextSeq) was also performed and compared to 16S rDNA Sanger sequencing. Bacteria were identified using MetaPhlAn4.</div></div><div><h3>Results</h3><div>Among the 73 samples, 20 (27 %, 17 patients) had a clinically relevant 16S rDNA Sanger sequencing result (used for patient management) while 11 (15 %, 9 patients) were considered contaminants. At the patient level, the sensitivity of CMg was 70 % (12/17) compared to 16S rDNA. In samples negative for 16S rDNA Sanger sequencing (n = 53), CMg identified clinically-relevant bacteria in 10 samples (19 %, 10 patients) with 14 additional bacteria.</div></div><div><h3>Conclusions</h3><div>CMg was not 100 % sensitive when compared to 16S, supporting that it may not be a suitable replacement. However, CMg did find additional bacteria in samples negative for 16S rDNA Sanger. CMg could therefore be positioned as a complementary to 16S rDNA Sanger sequencing.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151650"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379409","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":"The MgaSpn global transcriptional regulator mediates the biosynthesis of capsular polysaccharides and affects virulence via the uracil synthesis pathway in Streptococcus pneumoniae","authors":"Shuhui Wang ,&nbsp;Xinlin Guo ,&nbsp;Ye Tao ,&nbsp;Xuemei Zhang ,&nbsp;Weicai Suo ,&nbsp;Yapeng Zhang ,&nbsp;Li Lei ,&nbsp;Yibing Yin ,&nbsp;Yuqiang Zheng","doi":"10.1016/j.ijmm.2025.151648","DOIUrl":"10.1016/j.ijmm.2025.151648","url":null,"abstract":"<div><div>Uracil metabolism is an important step in the growth and metabolism of <em>Streptococcus pneumoniae</em>, and pyrimidine nucleotides play an important role in the expression and production of <em>S. pneumoniae</em> capsules. Mga<em>Spn</em>(<em>spd_1587</em>),as a transcriptional ragulator of host environment adaptation, regulates the biosynthesis of the capsules and phosphorylcholine. However, the underlying regulation mechanism between uracil metabolism and biosynthesis of capsules remains incompletely understood. Here, we first described the relationship between uracil metabolism and capsule expression via the <em>pyrR</em> gene(<em>spd_1134</em>) in <em>S. pneumoniae</em>. Electrophoretic mobility-shift assays (EMSAs) and DNase I footprinting assays showed a direct interaction between Mga<em>Spn</em> and the <em>pyrR</em> promoter (P_{<em>pyrR</em>}) at two specific binding sites. MgaSpn negatively regulated capsule production through <em>pyrR</em> as confirmed by complementing <em>pyrR</em> expression in D39Δ<em>mgaSpn</em>Δ<em>pyrR</em> (<em>mgaSpn</em> and <em>pyrR</em> double-defective strain). Virulence experiments showed that the Mga<em>Spn</em>-<em>pyrR</em> interaction was necessary for both pneumococcal colonization and invasive infection. For the first time, the present study demonstrated that the de novo synthesis gene <em>pyrR</em> of S. pneumoniae is regulated by the Mga<em>Spn</em> transcriptional regulator.Taken together,these results provide an insight into the regulation of capsule production mediated by uracil metabolism and its important roles in pneumococcal pathogenesis.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151648"},"PeriodicalIF":4.5,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420407","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":"PCR-detection rates of T. pallidum ssp. pallidum in swab samples from the Czech Republic (2004–2022): Combined RPR, IgM, and PCR tests efficiently detect active syphilis","authors":"Eliška Vrbová ,&nbsp;Petra Pospíšilová ,&nbsp;Eliška Dastychová ,&nbsp;Martina Kojanová ,&nbsp;Miluše Kreidlová ,&nbsp;Daniela Vaňousová ,&nbsp;Filip Rob ,&nbsp;Přemysl Procházka ,&nbsp;Alena Krchňáková ,&nbsp;Vladimír Vašků ,&nbsp;Radim Strnadel ,&nbsp;Olga Faustmannová ,&nbsp;Monika Dvořáková Heroldová ,&nbsp;Ivana Kuklová ,&nbsp;Hana Zákoucká ,&nbsp;David Šmajs","doi":"10.1016/j.ijmm.2025.151647","DOIUrl":"10.1016/j.ijmm.2025.151647","url":null,"abstract":"<div><div>Syphilis is a multistage sexually transmitted disease caused by <em>Treponema pallidum</em> ssp. <em>pallidum</em> (TPA). This study analyzed clinical samples collected from patients with a diagnosed syphilis infection from 2004–2022, isolated in the Czech Republic. Mucocutaneous swab samples (n = 543) from 543 patients were analyzed, and from these samples, 80.11 % (n = 435) were PCR positive, and 19.89 % (n = 108) were PCR negative for TPA DNA. Swabs were more often positive when collected from syphilis patients in the primary and secondary stages, compared to the latent or unknown stage. There was no significant difference in PCR positivity between the primary and secondary stages (p = 0.099). In IgM-positive patients, a statistically significant association with PCR-positivity was found in samples from seropositive (p = 0.033) and serodiscrepant (RPR negative) patients (p = 0.0006). When assessing our laboratory-defined cases of syphilis, the RPR, IgM, and PCR tests were similarly effective (within the range of 80.1–86.1 %). However, parallel testing with these methods was even more effective, i.e., RPR + PCR was 96.1 % effective and RPR + IgM + PCR was 97.8 % effective. A combination of RPR + PCR, or a combination of all three tests (RPR, IgM, and PCR) can therefore be used to reliably detect active syphilis cases, including reinfections. Our findings show that the reverse algorithm for detecting syphilis could be substantially improved by adding IgM and PCR testing.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151647"},"PeriodicalIF":4.5,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349635","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":"Pre-exposure to phage particles reduces their antibacterial therapeutic efficacy both in vitro and in vivo","authors":"Liwen Zhong ,&nbsp;Danjun Xu ,&nbsp;Jingyi He ,&nbsp;Lianhui Sun ,&nbsp;Guangjian Fan ,&nbsp;Ting Zhu ,&nbsp;Yufeng Yao ,&nbsp;Tingting Feng ,&nbsp;Zelin Cui","doi":"10.1016/j.ijmm.2025.151649","DOIUrl":"10.1016/j.ijmm.2025.151649","url":null,"abstract":"<div><h3>Objectives</h3><div>phage therapy is a promising approach for infections caused by drug-resistant bacteria; this study evaluated the impact of pre-exposure to phage particles on subsequent therapy. Mice were exposed intradermally (i.d.) to <em>Staphylococcus aureus</em> wide-host-range phage JD007, a member of the <em>Myoviridae</em> family.</div></div><div><h3>Methods</h3><div>phage-specific antibodies were detected using ELISA. Mice were infected with <em>S. aureus</em> in the same way to establish a dermal abscess model, and then the efficacy of phage therapy for the mice pre-exposed to JD007 was evaluated.</div></div><div><h3>Results</h3><div>JD007 could induce their specific IgM and IgG. IgM levels peaked on the 7th day following exposure, and IgG levels peaked on the 30th day after final immunization. Neutralization assays demonstrated that specific antibodies could reduce JD007’s infectivity to <em>S. aureus</em> in vitro. Furthermore, mice previously exposed to JD007 three times showed decreased phage therapeutic efficacies, leading to delayed recovery and even exacerbating abscesses. White blood cells and lymphocytes also increased. Despite pre-exposing the mice to JD007 once, the abscess areas following phage treatment did not differ from those of the infection group with naive mice. The western blot results showed that anti-phage antibodies could recognize the predicted major capsid protein and phage tail protein.</div></div><div><h3>Conclusions</h3><div>pre-exposure to phage particles may induce phage-neutralization antibodies and inhibit their therapeutic efficacies, delaying recovery or even exacerbating <em>S. aureus-</em>associated dermal abscesses for later treatment.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151649"},"PeriodicalIF":4.5,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420505","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":"Mycoplasma pneumoniae drives macrophage lipid uptake via GlpD-mediated oxidation, facilitating foam cell formation","authors":"Takeshi Yamamoto,&nbsp;Miki Okuno,&nbsp;Koichi Kuwano,&nbsp;Yoshitoshi Ogura","doi":"10.1016/j.ijmm.2025.151646","DOIUrl":"10.1016/j.ijmm.2025.151646","url":null,"abstract":"<div><div>Cardiovascular diseases, primarily caused by atherosclerosis, are a major public health concern worldwide. Atherosclerosis is characterized by chronic inflammation and lipid accumulation in the arterial wall, leading to plaque formation. In this process, macrophages play a crucial role by ingesting lipids and transforming into foam cells, which contribute to plaque instability and cardiovascular events. Recent studies have suggested that various pathogens are involved in the development of atherosclerosis, with <em>Mycoplasma pneumoniae</em> considered one of the potential candidates. Therefore, this study investigated whether this bacterium induces lipid accumulation in macrophages, which play a crucial role in the development of atherosclerosis, using the Raw264.7 model. Our findings revealed that <em>M. pneumoniae</em> infection promotes lipid droplet formation in macrophages. Glycerol 3-phosphate oxidase, GlpD, in the bacterium is involved in this process by producing reactive oxygen species, which in turn causes the oxidation of low-density lipoprotein. Furthermore, the significant increase in the expression of oxidized lipid receptors involved in the uptake of this oxidized lipid indicates that the bacteria promote lipid uptake in infected macrophages. These results suggest that <em>M. pneumoniae</em> has a direct pro-atherogenic effect, promoting the formation of atherosclerotic lesions through foam cell formation. Understanding the mechanisms by which <em>M. pneumoniae</em> influences atherosclerosis provides valuable insights for devising new therapeutic strategies for the prevention and management of cardiovascular diseases.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151646"},"PeriodicalIF":4.5,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143042877","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":"Characterization of carbapenem-resistant Klebsiella pneumoniae from blood cultures in Gaza Strip hospitals, Palestine","authors":"Nahed Al Laham ,&nbsp;Ahmed Al Afifi ,&nbsp;Alexander Mellmann ,&nbsp;Frieder Schaumburg","doi":"10.1016/j.ijmm.2025.151645","DOIUrl":"10.1016/j.ijmm.2025.151645","url":null,"abstract":"<div><h3>Background</h3><div>Carbapenem-resistant <em>Klebsiella pneumoniae</em> (CRKP) is a difficult to treat organism owing to limited therapeutic options. So far, little is known about the molecular characteristics of CRKP in Palestine.</div></div><div><h3>Objectives</h3><div>The aim of this study was to investigate the antimicrobial resistance patterns, multilocus sequence types (ST) and resistance genes among clinical <em>K. pneumoniae</em> isolates from hospitalized patients in Gaza Strip, Palestine.</div></div><div><h3>Methods</h3><div><em>K. pneumoniae</em> from blood cultures (n = 55) were collected at two hospitals in Gaza Strip (2023) and identified by MALDI-TOF-MS. Antimicrobial susceptibility testing was done using VITEK-2 automated systems. Carbapenemases were phenotypically detected. Whole genome sequencing (WGS) of all CRKP isolates was performed to assess determinants for carbapenem resistance and genotypes.</div></div><div><h3>Results</h3><div>Of all <em>K. pneumoniae</em> isolates, 40 % (n = 22/55) were CRKP. Among CRKP, cefiderocol showed the least resistance (46 %, n = 10/22) while ceftazidime/avibactam showed a synergistic effect with aztreonam (36 %, n = 8/22). The majority (86 %, n = 19/22) of CRKP carried metallo-β-lactamases, and only 9 % (n = 2/22) encoded OXA-48 carbapenemase. WGS of CRKP revealed that the predominant genotype is multilocus sequence type ST147 harboring <em>bla</em>_NDM-5 and <em>bla</em>_CTX-M-15.</div></div><div><h3>Conclusion</h3><div>The proportion of CRKP among all <em>K. pneumoniae</em> from bloodstream infection in Gaza Strip is high (40 %) and mainly associated with the <em>bla</em>_NDM-5-positive high-risk clone ST147.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151645"},"PeriodicalIF":4.5,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958167","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":"Prevalence of Borrelia burgdorferi sensu lato infection in the Czech Republic","authors":"Roman Chlibek ,&nbsp;Jan Smetana ,&nbsp;Kateřina Kybicová ,&nbsp;Martina Malikova ,&nbsp;Frederick J. Angulo ,&nbsp;Alexandra Loew-Baselli ,&nbsp;Ye Tan ,&nbsp;Aleš Ondřejíček ,&nbsp;Gordon Brestrich ,&nbsp;Andreas Pilz ,&nbsp;Jennifer C. Moïsi ,&nbsp;James H. Stark","doi":"10.1016/j.ijmm.2024.151644","DOIUrl":"10.1016/j.ijmm.2024.151644","url":null,"abstract":"<div><h3>Introduction</h3><div>Lyme borreliosis (LB), an infection caused by <em>Borrelia burgdorferi</em> sensu lato (Bbsl), is the most common tick-borne disease in Europe. To further characterize the LB burden in the Czech Republic, we conducted a seroprevalence study and estimated the incidence of symptomatic Bbsl infections.</div></div><div><h3>Methods</h3><div>Anti-Bbsl IgM and IgG antibodies were detected in sera collected from the adult population in 2011 −2012 by enzyme-linked immunosorbent assay and immunoblot tests at the National Reference Laboratory. The incidence of symptomatic Bbsl infections was estimated from the seroprevalence results and the symptomatic proportion and duration of persistence of anti-Bbsl IgG antibodies in Bbsl-infected individuals. Surveillance under-detection of symptomatic Bbsl infections was estimated by comparing surveillance-reported and seroprevalence-based incidence.</div></div><div><h3>Results</h3><div>Samples from 1996 adults were tested; the median age (range) was 45 (18 −87) years; 1037 (52.0 %) were female. The prevalence (with 95 % confidence interval) of anti-Bbsl IgG, and IgM and/or IgG (IgM/IgG) antibodies was 6.3 % (5.3 −7.5 %), and 9.5 % (8.3 −10.9 %), respectively. The IgM/IgG prevalence was 7.8 % (6.5 −9.2 %) in Bohemia and 15.3 % (12.2 −19.0 %) in Moravia. There were an estimated 30,563 (26,550 −34,962) symptomatic incident Bbsl infections in adults in the Czech Republic in 2012, for an incidence of 352.2 (306.0 −402.9) symptomatic Bbsl infections per 100,000 adults per year. There were an estimated 11 (10 −13) symptomatic Bbsl infections for each surveillance-reported LB case in the Czech Republic in 2012.</div></div><div><h3>Conclusions</h3><div>There is high incidence of symptomatic Bbsl infections in the Czech Republic, particularly in Moravia. Interventions are needed to address the substantial burden of LB in the Czech Republic.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151644"},"PeriodicalIF":4.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142958168","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":"Nasopharyngeal carriage of Staphylococcus aureus in a rural population, Sierra Leone","authors":"Lisa Maria Kleine ,&nbsp;Emmanuel Marx Kanu ,&nbsp;Tobias Grebe ,&nbsp;Desmond Mohamed Sesay ,&nbsp;Henning Loismann ,&nbsp;Maxwell Sesay ,&nbsp;Tom Theiler ,&nbsp;Viktoria Rudolf ,&nbsp;Alexander Mellmann ,&nbsp;Laura C. Kalkman ,&nbsp;Martin P. Grobusch ,&nbsp;Frieder Schaumburg","doi":"10.1016/j.ijmm.2024.151643","DOIUrl":"10.1016/j.ijmm.2024.151643","url":null,"abstract":"<div><h3>Background</h3><div>Nasopharyngeal colonization with <em>Staphylococcus aureus</em> is a risk factor for subsequent infection. Isolates from colonization can therefore provide important information on virulence factors and antimicrobial resistance when data from clinical isolates are lacking. The aim of this study was to assess colonization rates, resistance patterns and selected virulence factors of <em>S. aureus</em> from rural Sierra Leone.</div></div><div><h3>Methods</h3><div>Residents of randomly selected houses in Masanga, Sierra Leone were included in a cross-sectional study (8–11/2023). Participants were tested for nasopharyngeal <em>S. aureus</em> colonization using selective culture media. Risk factors for colonization were documented in a standardized questionnaire. Isolates were genotyped and tested for antimicrobial susceptibility and selected virulence factors (e.g. Panton-Valentine leukocidin, capsular types).</div></div><div><h3>Results</h3><div>Of 300 participants (62.7 % females, median age: 16 years), 168 (56 %) were colonized with <em>S. aureus-</em>related complex<em>;</em> six participants carried two different <em>S. aureus</em> genotypes, resulting in a total number of 174 isolates. Resistance to penicillin was predominant (97.1 %, 169/174), followed by tetracycline (66.1 %, 115/174), co-trimoxazole (56.9 %, 99/174) and oxacillin (24.1 %, 42/174, all <em>mecA</em>-positive, mostly associated with ST8/PVL-negative). PVL gene was detected in 21.3 % of isolates (37/174) mainly associated with ST15 and ST152. Except for past use of antimicrobials (p = 0.019), no specific risk factors such as comorbidities including hemoglobin variants were associated with <em>S. aureus</em> nasopharyngeal colonization.</div></div><div><h3>Conclusion</h3><div>The prevalence of methicillin-resistant and PVL-positive methicillin-susceptible <em>S. aureus</em> (MRSA/MSSA) is high in a rural community of asymptomatic carriers in Sierra Leone. Measures to contain the spread of MRSA, also in the community, are needed.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151643"},"PeriodicalIF":4.5,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142933443","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":"E. coli Nissle 1917 improves gut microbiota composition and serum metabolites to counteract atherosclerosis via the homocitrulline/Caspase 1/NLRP3/GSDMD axis","authors":"Huan Liu ,&nbsp;Xiaofeng Ma ,&nbsp;Xuefeng Yang ,&nbsp;Sujun Xiao ,&nbsp;Shao Ouyang ,&nbsp;Zhihao Hu ,&nbsp;Zhixiang Zhou ,&nbsp;Zhisheng Jiang","doi":"10.1016/j.ijmm.2024.151642","DOIUrl":"10.1016/j.ijmm.2024.151642","url":null,"abstract":"<div><h3>Background</h3><div>The probiotic <em>E. coli Nissle 1917</em> (EcN) alleviates the progression of various diseases, including colitis and tumors. However, EcN has not been studied in atherosclerosis. The study investigated the effects of EcN on atherosclerosis model mice and the potential mechanisms.</div></div><div><h3>Methods</h3><div>Mice in the high-fat diet (HFD) model were given EcN (1 × 10⁹ CFU/g) or homocitrulline (150 mg/L) by oral administration for 12 weeks. The EcN + antibiotic group was set up to investigate the effects of EcN combined with antibiotics on gut microbiota. The control group was utilized as the negative control. Atherosclerosis status, pyroptosis, gut microbiota, and serum metabolites of mice were examined.</div></div><div><h3>Results</h3><div>EcN treatment alleviated HFD-caused atherosclerotic plaque and lipid droplet production. EcN treatment reversed HFD-induced increases in total cholesterol, triglycerides, and low-density lipoprotein levels and decreases in high-density lipoprotein levels. EcN inhibited the HFD-caused rise in the expression of pyroptosis-related indicators (cleaved Caspase 1, GSDMD-N, NLRP3, IL-18, and IL-1β). The antibiotics partially reversed the effects of EcN on the model mice, suggesting that EcN regulated pyroptosis in the model mice through gut microbiota. Probiotic bacteria, such as <em>Lactobacillus</em> and <em>Muribaculum</em>, were mainly enriched in the EcN and EcN + antibiotic groups, while <em>Helicobacter</em>, <em>Alistipes</em>, and <em>Rikenella</em> were depleted, suggesting that EcN and EcN + antibiotics could alleviate disorders of gut microbiota in the model mice. EcN reversed the trend of HFD-induced decrease of some metabolites, such as 2-methyl-5-nitroimidazole-1-ethanol, methionine sulfoxide, and shikimate 3-phosphate, and inhibited the increase of some metabolites, such as kynurenine, oxoadipate, and homocitrulline. In addition, homocitrulline showed the opposite effects of EcN in the model mice. Homocitrulline could bind to pyroptosis-related proteins to aggravate ox-LDL-induced endothelial cell pyroptosis.</div></div><div><h3>Conclusion</h3><div>EcN could alleviate atherosclerosis development by ameliorating HFD-induced disorders of gut microbiota and serum metabolites (such as homocitrulline) to alleviate pyroptosis, which may be associated with homocitrulline/Caspase 1/NLRP3/GSDMD axis. Our study lays the foundation for the development of promising drugs for atherosclerosis in the future.</div></div>","PeriodicalId":50312,"journal":{"name":"International Journal of Medical Microbiology","volume":"318 ","pages":"Article 151642"},"PeriodicalIF":4.5,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142916117","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}