International Journal of Infectious Diseases最新文献

{"title":"Risk factors for brucellosis relapse and focal complications: A nine-year multicenter study in an endemic region.","authors":"Maryam Dadar, Niloofar Sadooghi, Fereshteh Ansari, Seyyed Ahmad Hashemi, Hamed Ghasemzadeh Moghaddam, Yaser Panahi, Afshin Delshad, Jorge C Wallach","doi":"10.1016/j.ijid.2025.108047","DOIUrl":"10.1016/j.ijid.2025.108047","url":null,"abstract":"<p><strong>Objectives: </strong>Brucellosis remains a significant zoonotic disease in endemic regions, with relapse and focal complications posing significant clinical challenges. This study aimed to identify risk factors associated with brucellosis relapse and focal disease in North Khorasan, Iran, over a nine-year period.</p><p><strong>Methods: </strong>A retrospective analysis was conducted on 2568 confirmed brucellosis cases from 2015 to 2024, using data from multiple centers. Patients were diagnosed based on serological tests and categorized into relapse or focal brucellosis groups. Univariate and multivariate logistic regression models were used to analyze the demographic, clinical, and epidemiological variables.</p><p><strong>Results: </strong>Relapse rates varied significantly by region. Of these, the relapse rate was 12.2% among patients with complications, compared to 9.5% in those without, not statistically significant, indicating that complications do not predict relapse. Predictors of relapse included older age, female sex, agricultural occupation, and specific Coombs-Wright titers (1/40 and 1/80). Focal complications (4.6%) most commonly involved arthritis (1.3%) and spondylitis (1%). Predictors of focal brucellosis included autumn onset, delayed diagnosis ≥3 months, hospitalization, and streptomycin use for 8-14 days.</p><p><strong>Conclusions: </strong>Brucellosis relapse and focal disease are influenced by demographic, occupational, geographic, and treatment-related factors. These findings underscore the importance of early diagnosis and optimized antibiotic regimens in preventing complications.</p>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":" ","pages":"108047"},"PeriodicalIF":4.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145015119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prototheca wickerhamii causing toe infection presenting initially as gouty arthritis: A rare case report","authors":"Rong Wang ,&nbsp;Yuyuan Xue ,&nbsp;Zirong Wu ,&nbsp;Mingjing Wei ,&nbsp;Nongxin Wu ,&nbsp;Jian Guo","doi":"10.1016/j.ijid.2025.108049","DOIUrl":"10.1016/j.ijid.2025.108049","url":null,"abstract":"<div><div><em>Prototheca</em>, a genus of opportunistic pathogenic microalgae, can cause protothecosis in humans and animals, manifesting as cutaneous lesions or disseminated/systemic infections. This report describes a rare case of <em>Prototheca wickerhamii</em> toe infection in a 78-year-old Chinese male, presenting initially as gouty arthritis. The patient, who worked in fish farming with frequent water exposure, had a history of herpes zoster and hypertension. For 3 years, he experienced recurrent episodes of erythema, swelling, and pain in the bilateral first metatarsophalangeal joints without identifiable triggers. Symptoms worsened over the past month, leading to hospital admission with suspected gout. Physical examination revealed a 1 cm ulcer on the right foot with a dark red granulation tissue base, extending 4 cm deep. The surrounding skin was erythematous, swollen, exudative, and markedly tender. Laboratory findings showed normal serum uric acid (354 µmol/L) but elevated neutrophil percentage (82.1%). Magnetic resonance imaging (MRI) suggested possible gouty arthritis in the right foot, but no urate crystal deposition was evident. Five days later, re-evaluation revealed significantly elevated interleukin levels (IL-6 &gt; 2500 pg/mL, IL-8 157.29 pg/mL), indicating a robust new inflammatory response, with no significant improvement in local symptoms. Concurrently, deep tissue sampling and microbiological investigations (including histopathology, blood agar culture, fluorescent staining, Matrix-Assisted Laser Desorption/Ionization - Time Of Flight (MALDI-TOF) mass spectrometry) and Internal Transcribed Spacer (ITS) sequencing confirmed <em>P. wickerhamii</em> infection. Antifungal therapy was switched to itraconazole, resulting in symptom improvement within 5 days, and the patient was discharged. This case highlights the variable, masquerading, and potentially severe clinical presentations of <em>P. wickerhamii</em> infection. It underscores the importance of heightened awareness for microbiological screening in cases of suspected “gout” with persistent deep ulcers, particularly in individuals with relevant occupational or environmental exposure histories, especially with normal serum uric acid. Deep tissue sampling for definitive diagnosis is crucial to avoid empiric corticosteroid therapy, which may exacerbate opportunistic infections.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108049"},"PeriodicalIF":4.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145008295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rising tide of Vector-Borne Diseases in Europe - Surveillance, Clinical Awareness, and Public Health Preparedness","authors":"Eskild Petersen ,&nbsp;Giuseppe Ippolito ,&nbsp;Alimuddin Zumla","doi":"10.1016/j.ijid.2025.108038","DOIUrl":"10.1016/j.ijid.2025.108038","url":null,"abstract":"","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"159 ","pages":"Article 108038"},"PeriodicalIF":4.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Why do echinocandins fail? Identifying key predictors to improve clinical outcomes of candida bloodstream infections: a retrospective multicenter cohort study","authors":"Davide Fiore Bavaro ,&nbsp;Lucia Diella ,&nbsp;Alessandro De Angelis ,&nbsp;Massimo Vanoni ,&nbsp;Alessandra Belati ,&nbsp;Laura De Santis ,&nbsp;Linda Bussini ,&nbsp;Laura Montemurro ,&nbsp;Roberto Papale ,&nbsp;Luigi Ronga ,&nbsp;Maria Calabrò ,&nbsp;Erminia Casari ,&nbsp;Monica Stufano ,&nbsp;Lidia Dalfino ,&nbsp;Federica Tordato ,&nbsp;Paola Morelli ,&nbsp;Nadia Fusilli ,&nbsp;Gianluca Castellani ,&nbsp;Elena Costantini ,&nbsp;Francesco Di Gennaro ,&nbsp;Michele Bartoletti","doi":"10.1016/j.ijid.2025.108046","DOIUrl":"10.1016/j.ijid.2025.108046","url":null,"abstract":"<div><h3>Background</h3><div>Echinocandins represent first-line therapy for Candida Bloodstream Infections (C-BSIs). Incidence of treatment failure (TF) remains high with unclear risk factors. Aim: to evaluate predictors of echinocandin TF for C-BSIs.</div></div><div><h3>Methods</h3><div>Retrospective observational multicenter study, enrolling all patients with C-BSI treated with echinocandin from 01/06/2020 to 30/06/2023 in four Italian Hospitals.</div></div><div><h3>Primary outcome</h3><div>to evaluate predictors of TF defined as a composite of: i)transfer to ICU or any worsening in organ dysfunction at day 5 of therapy; ii)Persistent C-BSI; iii)Echinocandin discontinuation for any reason; iv)Onset of a new infection site by <em>Candida spp.</em> during treatment.</div></div><div><h3>Secondary outcome</h3><div>90-day all-cause mortality. Cox regression and treatment-effect were used, along with inverse-probability of treatment-weighting (IPTW) to adjust cohort treatment-assignment bias.</div></div><div><h3>Results</h3><div>Overall, 218 patients were enrolled. Median (q1-q3) age was 72 (56-78), 55% male. In 33% and 63% of cases, septic shock at presentation and C-BSIs by non-albicans strains were reported. Importantly, 68 (31%) patients received high dosage echinocandin (“HDE”: increase of 30-50% of standard dosage), according to clinical judgement. Eighty-two (38%) experienced TF; 90-day all-cause mortality was 30%, significantly higher in TF-group (<em>P &lt; 0.</em>001). At multivariable Cox-regression analysis, obesity, septic shock, and increased MIC to echinocandins were predictors of TF; presence of removable intravascular devices and HDE resulted protective. After adjustment by inverse-probability of treatment-weighting, HDE still reduced TF risk in patients admitted to the ICU, with SOFA score&lt;6, BMI&gt;30, or with serum albumin concentration ≤2,5gr/dL.</div></div><div><h3>Conclusion</h3><div>Several clinical and microbiological factors could influence the echinocandin TF. Interestingly, in patients at risk for echinocandin TF, HDE may be protective.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108046"},"PeriodicalIF":4.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Managing life-threatening complications of dengue fever in two sickle cell disease patients: A case series","authors":"Narcisse Elenga","doi":"10.1016/j.ijid.2025.108048","DOIUrl":"10.1016/j.ijid.2025.108048","url":null,"abstract":"<div><div>Patients with sickle cell disease (SCD) infected with dengue virus are at high risk of developing severe complications. However, the optimal management approach for this patient population remains unclear. We report two cases of dengue-associated multiorgan failure in adolescents with hemoglobin SC (HbSC) disease, both of whom recovered following structured symptomatic management. Drawing upon the pathophysiological insights from existing literature, we propose an algorithm to guide clinical management in such complex cases.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108048"},"PeriodicalIF":4.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145006140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic accuracy of a host response test in suspected community-Acquired pneumonia during the COVID-19 era","authors":"Christina S. Saghaug ,&nbsp;Dagfinn L. Markussen ,&nbsp;Siri T. Knoop ,&nbsp;Benedicte C. Holvik ,&nbsp;Sondre Serigstad ,&nbsp;Elling Ulvestad ,&nbsp;Christian Ritz ,&nbsp;Synne Jenum ,&nbsp;Harleen M.S. Grewal","doi":"10.1016/j.ijid.2025.108045","DOIUrl":"10.1016/j.ijid.2025.108045","url":null,"abstract":"<div><div>Community-acquired pneumonia [CAP] is a leading cause of morbidity and mortality, often complicated by diagnostic uncertainty and antibiotic overuse. This study evaluated the MeMed BV® host-response test in adults with suspected CAP, using clinical management and molecular detection as reference standards.</div><div>Among 744 patients presenting with suspected CAP at Haukeland University Hospital, Bergen, Norway (2019-2023), across three prospective studies, 453 were included in the present study. Patients were classified using: [<span><span>1</span></span>] clinical management [antibiotic timing/duration], and [<span><span>2</span></span>] molecular detection via BioFire® FilmArray Pneumonia Plus panel on lower respiratory tract samples. MeMed BV® testing was performed retrospectively on stored serum/plasma, categorising results as bacterial, viral, or equivocal. Healthy controls [<em>n</em> = 20] were also tested.</div><div>Among 442 patients classified by clinical management, the MeMed BV® test demonstrated a positive percent agreement [PPA] of 90.0% (95% CI: 86.4-92.7) and a negative percent agreement [NPA] was 44.1% (95% CI: 34.4-54.2). In 370 patients classified by molecular testing, PPA was 88.2% (95% CI: 83.6-91.7) and NPA was 30.1% (95% CI: 20.8-41.4. Equivocal results occurred in 7.5%. The test agreed with clinical management in 96.1% of cases with no detected pathogen. None of the healthy controls had bacterial scores.</div></div><div><h3>Conclusion</h3><div>MeMed BV® demonstrated high sensitivity in identifying bacterial infections but limited specificity in viral infections, notably SARS-CoV-2. It may aid early triage when combined with clinical and microbiological data.</div></div><div><h3>Trial registration</h3><div>ClinicalTrials.gov NCT04660084</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108045"},"PeriodicalIF":4.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends in the healthcare burden of hepatitis C after the introduction of direct-acting antivirals in Japan, 2013-2022: A national claims database study in Japan","authors":"Shimpei Yamashita ,&nbsp;Naoki Kanda ,&nbsp;Hideki Hashimoto ,&nbsp;Hiromasa Yoshimoto ,&nbsp;Kazuo Goda ,&nbsp;Naohiro Mitsutake ,&nbsp;Shuji Hatakeyama","doi":"10.1016/j.ijid.2025.108043","DOIUrl":"10.1016/j.ijid.2025.108043","url":null,"abstract":"<div><h3>Objectives</h3><div>To describe trends in the incidences of chronic hepatitis C, hepatocellular carcinoma (HCC), and related healthcare burden after the introduction of interferon-free direct-acting antivirals (DAAs).</div></div><div><h3>Methods</h3><div>This repeated cross-sectional study (time trend analysis) examined chronic hepatitis C and related healthcare, including HCC, using national claims data covering &gt;98% of healthcare services in Japan between fiscal years 2013 and 2022.</div></div><div><h3>Results</h3><div>During the study period, 357,877 patients were treated with DAAs. The prevalence of individuals receiving care for chronic hepatitis C decreased by 40% (95% confidence interval [CI]: 40-40%), from 0.54% in 2013 to 0.33% in 2022. Among individuals with HIV, the reduction was smaller, at 16% (95% CI: 10-20%), with a prevalence of 3.82% in 2022. The annual incidence of newly diagnosed HCC decreased by 69% (95% CI: 68-70%), accompanied by a reduction in HCC treatments. Annual healthcare costs for individuals with chronic hepatitis C peaked in 2015 and decreased to 65% of 2013 levels by 2022.</div></div><div><h3>Conclusion</h3><div>During the 10-y DAA era, the healthcare burden of hepatitis C declined substantially in Japan. Enhanced efforts in prevention, screening, and treatment are critical for the eradication of hepatitis C, particularly among high-risk populations, such as individuals with HIV.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108043"},"PeriodicalIF":4.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delayed CD4 cell recovery in HIV-associated disseminated nontuberculous mycobacterial disease: A case-control study","authors":"Kai Katzschner ,&nbsp;Thomas Wichelhaus ,&nbsp;Timo Wolf ,&nbsp;Benjamin Marx ,&nbsp;Iulia Dahmer ,&nbsp;Michael Paulitsch ,&nbsp;Annette Haberl ,&nbsp;Gundolf Schüttfort ,&nbsp;Pavel Khaykin ,&nbsp;Markus Bickel ,&nbsp;Gerrit Burger ,&nbsp;Christoph Stephan","doi":"10.1016/j.ijid.2025.108037","DOIUrl":"10.1016/j.ijid.2025.108037","url":null,"abstract":"<div><h3>Objectives</h3><div>Disseminated nontuberculous mycobacterial disease (dNTMd) remains a rare but serious complication in people living with HIV (PLWH). This study aimed to assess whether dNTMd independently contributes to delayed clusters of differentiation 4 (CD4) cell recovery after antiretroviral therapy (ART) initiation.</div></div><div><h3>Methods</h3><div>This retrospective 1:3 single center case-control study analyzed patient data from 2004 to 2023. PLWH and dNTMd (cases, n = 20) were matched to PLWH without evidence for mycobacterial infection (controls, n = 60) according to sex, age (±3 years), ART start date (±3 years), and baseline CD4 cell count (±100/μl). CD4 cell counts were evaluated at 10 time spans over 2 years after ART initiation using mixed median regression. Logistic regression models explored clinical and laboratory predictors of dNTMd.</div></div><div><h3>Results</h3><div>CD4 cell count recovery was significantly delayed in the dNTMd group (<em>P</em> = 0.006), although viral suppression rates were similar. Five variables were associated with dNTMd: low body mass index, high alkaline phosphatase, low hemoglobin, elevated C-reactive protein, and higher number of hospitalizations.</div></div><div><h3>Conclusions</h3><div>We demonstrated a link between dNTMd and significantly impaired CD4 cell count recovery in PLWH after ART initiation, independent of baseline results and viral suppression. A composite of five clinical and laboratory parameters may help identify patients at risk. Close clinical monitoring and personalized treatment approaches in PLWH with dNTMd is essential.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108037"},"PeriodicalIF":4.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A disease suppression strategy in action: The impact of non-pharmaceutical interventions in the COVID-19 pandemic in Denmark","authors":"Lone Simonsen ,&nbsp;Rasmus Kristoffer Pedersen ,&nbsp;Viggo Andreasen ,&nbsp;Tyra Grove Krause ,&nbsp;Eskild Petersen","doi":"10.1016/j.ijid.2025.108039","DOIUrl":"10.1016/j.ijid.2025.108039","url":null,"abstract":"<div><div>When a new pandemic virus emerges in a naive population, the only control options are non-pharmaceutical interventions (NPIs) until vaccines or effective treatments become available. Here, we report on the Danish suppression strategy and use of a combination of NPIs with a notable absence of extremely strict measures (such as stay-at-home orders). Only 7% of Danes were infected (serological evidence) in the first year of the pandemic, compared with 50% in Lombardy in the first wave alone. This low attack rate was accomplished by initial rapid intervention with a free-of-charge mass testing program beginning in October 2020, a strong digital data infrastructure, timely contact tracing and voluntary home isolation, real-time reporting of surveillance data, and a high degree of public trust. The individual contribution of each NPI to the pandemic control is difficult to assess; yet, evidence points to the mass testing program as being particularly effective in removing infected individuals from the pool. In January 2021, vaccines became available, and 96% of Danes over 50 years of age were vaccinated twice with an mRNA vaccine by summer. On February 1, 2022, while facing the Omicron variant and with the older adult newly boosted, Denmark became the first country to drop all NPIs. A few months later, 70% of the population had been infected with the Omicron variant, showing the SARS-CoV-2 transmission potential when unmitigated. Denmark was only close to intensive care unit capacity during the second wave in winter 2020-2021, when 5% of the population was infected. In conclusion, the effectiveness of the combined NPIs is evident due to the low (&lt;10%) attack rate in the first two waves before vaccines became available, far from the experience of unmitigated COVID-19 in Lombardy in spring 2020, with a 50% attack rate and catastropic levels of severe morbidity and mortality.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108039"},"PeriodicalIF":4.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145000584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential application of MALDI-TOF MS to identify Streptococcus parapneumoniae, an emerging pathogen previously misidentified as Streptococcus pneumoniae","authors":"Yan Zhao ,&nbsp;Yuanchao Ma ,&nbsp;Hwei Huih Lee ,&nbsp;Wing Ho Li ,&nbsp;Antonio Hung-Yee Ngan ,&nbsp;Jonathan Hon-Kwan Chen ,&nbsp;Simon Yung-Chun So ,&nbsp;Vincent Chi-Chung Cheng ,&nbsp;Kwok-Yung Yuen ,&nbsp;Man Lung Yeung ,&nbsp;Jade Lee-Lee Teng","doi":"10.1016/j.ijid.2025.108042","DOIUrl":"10.1016/j.ijid.2025.108042","url":null,"abstract":"<div><h3>Objectives</h3><div>Accurate identification of <em>Streptococcus</em> species is critical for clinical management and epidemiology. Misidentification of <em>Streptococcus parapneumoniae</em> as <em>Streptococcus pneumoniae</em> can hinder diagnosis and affect treatment outcomes.</div></div><div><h3>Methods</h3><div>From 385 archived <em>S. pneumoniae</em> isolates, species-specific polymerase chain reaction (PCR) was used to identify potential <em>S. parapneumoniae</em>. Confirmatory species determination, virulence, and antimicrobial resistance profile analyses were performed through whole-genome sequencing (WGS), phylogenomic, and comparative genomic analyses. Matrix-associated laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) spectral analysis aimed to identify biomarkers for <em>S. parapneumoniae</em>.</div></div><div><h3>Results</h3><div>Three <em>S. parapneumoniae</em> strains, representing a novel species first identified in Japan in 2024, were isolated from patients with respiratory infections in Hong Kong. WGS showed &gt;99% average nucleotide identity (ANI) with <em>S. parapneumoniae</em> SP4011^T, distinct from <em>S. pneumoniae</em> (&lt;94%). These strains possessed virulence factors similar to <em>S. pneumoniae</em>, suggesting pathogenic potential. All isolates exhibited multidrug and levofloxacin resistance, unlike local <em>S. pneumoniae</em> strains. MALDI-TOF MS identified two peaks (<em>m/z</em> 6,399 and <em>m/z</em> 6,960) unique to <em>S. parapneumoniae.</em></div></div><div><h3>Conclusions</h3><div>The multidrug resistance of <em>S. parapneumoniae</em> complicates antimicrobial resistance surveillance data and empirical treatment accuracy for <em>S. pneumoniae</em>. The identified discriminatory peaks offer promising tools for accurate species identification. The prevalence of <em>S. parapneumoniae</em> is likely underestimated; expanded surveillance is warranted to determine its true distribution and clinical significance.</div></div>","PeriodicalId":14006,"journal":{"name":"International Journal of Infectious Diseases","volume":"160 ","pages":"Article 108042"},"PeriodicalIF":4.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144992461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}