Journal of Microbiology Immunology and Infection最新文献

{"title":"Clinical impact of Moraxella catarrhalis detection in respiratory illnesses: a comparative study of pediatric and adult populations in Taiwan.","authors":"Yen-Chieh Chin, Tai-Fen Lee, Yu-Tsung Huang, Shu-Yuan Ho, Ya-Li Hu, Ting-Yu Yen, Kuan-Ying Huang, Chun-Yi Lu, Li-Min Huang, Luan-Yin Chang","doi":"10.1016/j.jmii.2026.08.006","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.08.006","url":null,"abstract":"<p><strong>Background: </strong>Moraxella catarrhalis is a prevalent respiratory pathogen in children and adults. While its roles in acute otitis media and chronic obstructive pulmonary disease exacerbations are well-established, its clinical significance in respiratory specimens-especially concerning co-pathogens and disease severity-remains unclear in the post-pneumococcal conjugate vaccine and post-COVID-19 era.</p><p><strong>Methods: </strong>We retrospectively analyzed all patients with M. catarrhalis-positive clinical specimens collected at a tertiary medical center in Taiwan from January 2015 to December 2023. We compared demographics, comorbidities, clinical features, and outcomes between pediatric (<18 years) and adult patients. Seasonal patterns were assessed using χ² tests and a negative binomial regression model for secular trends. Age-specific multivariable logistic regression identified factors associated with respiratory failure.</p><p><strong>Results: </strong>Among 731 patients, 515 were children and 216 were adults. Pediatric cases often involved viral co-detection, while adults showed more polymicrobial bacterial detection. Prematurity, asthma, and allergic diseases were common in children, whereas chronic kidney disease, cardiovascular disease, and malignancy prevailed in adults. Children typically presented with upper or non-pneumonic lower respiratory tract illness, while adults had higher pneumonia rates. Monthly case counts peaked in late autumn and winter, with this pattern less pronounced after calendar year adjustments. Prematurity (aOR, 3.97), rhinovirus co-detection (aOR, 4.23) and Gram-negative bacilli detection (aOR 4.90) were linked to respiratory failure in children, while chronic kidney disease (aOR, 3.60) and viral co-detection (aOR, 8.31) were significant in adults.</p><p><strong>Conclusion: </strong>The clinical implications of M. catarrhalis detection differ by age, highlighting distinct vulnerabilities and microbial interactions.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148876762","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":"Degree of major histocompatibility complex mismatching may be detrimental to B cell functional reconstitution after hematopoietic stem cell transplantation in infants with severe combined immunodeficiency.","authors":"Chih-An Chen, Ching-Wei Lin, Yuan-Ning Yang, Chao-Neng Cheng, Jiann-Shiuh Chen, Yu-Chien Wang, Mei-Tsz Su, Chiu-Ching Kao, Chu-Han Hsieh, Hsin-Ying Hsieh, Hsiu-Hao Chang, Hsin-Hui Yu, Yin-Hsiu Chien, Chi-Chang Shieh","doi":"10.1016/j.jmii.2026.08.005","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.08.005","url":null,"abstract":"<p><strong>Background: </strong>In addition to the main goal of T cell engraftment, the functional reconstitution of B cell function is an important indicator of successful hematopoietic stem cell transplantation (HSCT) for severe combined immunodeficiency (SCID) patients.</p><p><strong>Objective: </strong>Poor functional reconstitution of B cell function may relate to lower degree of Major Histocompatibility Complex (MHC) compatibility in children with SCID after HSCT.</p><p><strong>Study design: </strong>We aimed to analyze the outcomes of HSCT in children with SCID in a referral tertiary center in southern Taiwan. We collected data retrospectively from all seven infants with SCID who received HSCT and were followed-up at the center during 2005-2025.</p><p><strong>Results: </strong>All patients survived with reconstituted T cells during the follow-up period. One hundred percent T cell engraftment of donor cells are noted in all patients while variable degrees of chimerism were noted in other leukocytes. However, the extent of B cell chimerism does not appear to determine the outcome of B cell functional recovery. Two haploidentical-transplant patients required regular immunoglobulin supplement to prevent frequent infections.</p><p><strong>Conclusion: </strong>Newborn screening for SCID may successfully identified patients with SCID and early HSCT helped them to survive the previously fatal disease. However, poor immunoglobulin recovery requiring lifelong immunoglobulin replacement was observed in the two patients who underwent haploidentical HSCT. Haploidentical transplantation as a potential cause of compromised B cell recovery in SCID treatment should be further investigated.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148814235","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":"Contrasting the impact of fluoroquinolone exposure on aortic aneurysm and dissection risk: Insights from a US multicenter database study.","authors":"Renin Chang, Thomas Yen-Ting Chen, Shiow-Ing Wang, Yao-Shen Chen, Yao-Min Hung, James Cheng-Chung Wei","doi":"10.1016/j.jmii.2026.08.004","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.08.004","url":null,"abstract":"<p><strong>Aims: </strong>To evaluate the association between fluoroquinolone (FQ) use and incident aortic aneurysm (AA), aortic dissection (AD), aneurysm-related surgery, and all-cause mortality in a large U.S. multicenter database and to explore the influence of comparator selection and infection-related confounding.</p><p><strong>Methods and results: </strong>A retrospective cohort of 180,936 patients prescribed FQs was compared with 180,936 propensity score-matched patients who received comparator antibiotics. Matching was conducted 1:1 based on demographics, socioeconomic status, lifestyle factors, comorbidities, and medication use. The primary outcome was the 90-day incidence of AA/AD, evaluated using adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs). The FQ cohort was not found with an elevated risk of AA (aHR:0.95; 95%CI:0.83-1.08) but with elevated risk of AD (aHR:1.38; 95%CI:1.01-1.89), aneurysm-related surgery (aHR:2.32; 95%CI:1.75-3.08) and mortality (aHR:2.75, 95%CI:2.62-2.89). Exploratory sensitivity analyses using alternative comparator groups yielded substantially different estimates, including lower observed risks of AA/AD when last-line antibiotics were used as comparators (AA: aHR, 0.53 [95%CI:0.47-0.60]; AD: aHR, 0.31 [95%CI:0.23-0.43]). These findings suggest important residual confounding related to comparator selection, infection indication, and infection severity.</p><p><strong>Conclusion: </strong>In the primary analysis, FQ use was not associated with overall AA but was associated with increased risks of AD, aneurysm-related surgery, and mortality. Estimates varied substantially across comparator-based sensitivity analyses, suggesting potential residual confounding by indication and infection severity. These findings should not be interpreted as establishing the absence of AA/AD risk associated with FQ use.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148868222","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":"The clinical significance of positive acid-fast bacilli smear in respiratory specimens from patients completing anti-tuberculosis treatment.","authors":"Ping-Huai Wang, Wan-Lun Wu, Hsin-Ni Huang, Yao-Wen Kuo, Yu-Tsung Huang, Chin-Chung Shu","doi":"10.1016/j.jmii.2026.08.003","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.08.003","url":null,"abstract":"<p><strong>Purpose: </strong>The clinical significance of positive acid-fast bacilli (AFB) by microscopy smear in respiratory specimens remains poorly understood in patients with a history of successfully treated pulmonary tuberculosis (PTB).</p><p><strong>Methods: </strong>A retrospective study was conducted to screen patients with PTB between 2009 and 2020. They were enrolled if microscopic smears of AFB were positive after they completed successful treatments. The first date of a positive AFB smear after treatment completion was denoted as the index date. According to whether culture results indicated Mycobacterium tuberculosis (Mtb), subjects were categorized into Mtb and non-Mtb groups.</p><p><strong>Results: </strong>A total of 84 patients were included, with 27 (32.1%) patients in the Mtb group. The Mtb group had a higher proportion of active smokers and strong positive smears of AFB than the non-Mtb group. Radiologically, the rate of cavitation on the index date was significantly higher in the Mtb group than in the non-Mtb group (77.8 vs. 22.8%, p < 0.001, respectively). By multivariable logistic regression analysis, cavitation on the index date [adjusted odds ratio (aOR): 6.80, p = 0.003] and active smoker (aOR: 7.14, p = 0.044, vs. non-smoker) were independent risk factors of the Mtb group. There were 52 patients (61.9%) having polymerase chain reaction (PCR) tests. While the sensitivity of PCR was 94.1%, the specificity was only 60.0%.</p><p><strong>Conclusions: </strong>The detection of AFB by microscopic smears and positive PCR might not be sufficient for diagnosing recurrent PTB. Integrating the clinical factors, including active smoking and cavitation, might enhance the diagnostic power.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148802109","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":"Microbial profiles in non-leptospirosis acute undifferentiated febrile illness: Associations with clinical parameters and implications for diagnosis.","authors":"Pavaret Sivapornnukul, Umaporn Limothai, Sasipha Tachaboon, Janejira Dinhuzen, Rungrat Jitvaropas, Chanatip Thanasarnthungcharoen, Suwalak Chitcharoen, Vorthon Sawaswong, Prangwalai Chanchaem, Sunchai Payungporn, Nattachai Srisawat","doi":"10.1016/j.jmii.2026.08.001","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.08.001","url":null,"abstract":"<p><strong>Background: </strong>Acute undifferentiated febrile illness (AUF) remains a challenge in medical diagnosis. This study aimed to investigate the microbial profiles of non-leptospirosis AUF patients from Sisaket province, an endemic region for leptospirosis, and to elucidate their associations with clinical parameters.</p><p><strong>Methods: </strong>Blood samples from 78 non-leptospirosis AUF patients were confirmed negative for leptospirosis by bacterial culture, lipL32-qPCR, and the microscopic agglutination test. 16S rDNA and ITS sequencing were used to identify bacterial and fungal communities. Patients were categorized into Only Bacteria (OB), Only Fungi (OF), and Both Bacteria and Fungi (BBF) groups. Microbial differences were assessed using Principal Coordinate Analysis (PCoA) and associations with clinical variables analyzed using Generalized Linear Models (GLM).</p><p><strong>Results: </strong>Stenotrophomonas emerged as the predominant bacterial genus in both OB and BBF groups, while Aspergillus and Candida dominated the fungal profiles in OF and BBF groups. Bacterial compositions differed significantly between OB and BBF groups (P = 0.002), indicating that concurrent bacterial-fungal presence alters bacterial community structure, whereas fungal profiles remained stable. GLM analysis revealed significant associations between specific microbial taxa and clinical parameters, including blood pressure, temperature, hematological indices, and liver function tests.</p><p><strong>Conclusion: </strong>Our study sheds light on the microbial landscape in non-leptospirosis AUF patients, establishing connections with clinical parameters. This holistic approach enriches our understanding of AUF's etiology, presenting avenues for targeted diagnostic and therapeutic strategies in systemic infections.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148802006","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":"Extracellular vesicles of Mucor lusitanicus reveal virulence-associated protein cargo.","authors":"Sándor Kiss-Vetráb, Áron Péter, Kitti Bauer, Bernadett Vágó, Naomi Varghese, Tamás Ferenc Polgár, Zoltán Kele, Gábor Kecskeméti, Csaba Vágvölgyi, Tamás Papp, Gábor Nagy","doi":"10.1016/j.jmii.2026.08.002","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.08.002","url":null,"abstract":"<p><p>In this study, we report the first proteomic characterization of extracellular vesicles (EVs) in a Mucorales species. EV cargo of Mucor lusitanicus contains multiple virulence-associated and biomarker-relevant proteins, supporting a potential role for EVs in host-pathogen interaction and providing a basis for future diagnostic and functional studies.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148714703","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":"Clinical outcomes in patients hospitalized for COVID-19 in the periods of non-Omicron and Omicron variant dominance.","authors":"Yi-Jhen Hsieh, Bing-Chen Wu, Shih-Wei Huang, Chen-Chuan Hsu, Hsin-I Cheng, Ko-Wei Chang, Allen Chung-Cheng Huang, Chang-Wei Lin, Ting-Yu Lin, Horng-Chyuan Lin, Cheng-Hsun Chiu, Shu-Min Lin","doi":"10.1016/j.jmii.2026.07.010","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.07.010","url":null,"abstract":"<p><strong>Background: </strong>Omicron is known for its higher transmissibility and milder respiratory symptoms than those of other SARS-CoV-2 variants. How comorbidities contribute to mortality outcomes in Omicron-related COVID-19 remains unclear. This study compared clinical features and outcomes between Omicron and non-Omicron variants and identified risk factors for in-hospital mortality.</p><p><strong>Methods: </strong>This retrospective cohort study was conducted from April 2020 to September 2022. Patients with COVID-19 infection were divided into Omicron and non-Omicron groups. Demographic data, laboratory results, and treatment information were collected and analyzed. Clinical outcomes for different variants were analyzed.</p><p><strong>Results: </strong>The Omicron group had a greater burden of comorbidities but exhibited lower COVID-19 disease severity and fewer complications than did the non-Omicron group. Overall mortality was relatively high in the Omicron group, primarily due to non-COVID-related causes. In multivariate analysis, a Charlson comorbidity index score of ≥3 (odds ratio [OR] = 4.60, 95% confidence interval [CI] = 1.94-10.91, p < 0.001), severe or critical COVID-19 (OR = 1.60, 95% CI = 1.24-2.07, p < 0.001), a high white blood cell count (OR = 1.00, 95% CI = 1.00-1.00, p = 0.021), and a high C-reactive protein level (OR = 1.01, 95% CI = 1.00-1.01, p = 0.003) emerged as positive predictors of COVID-19-related mortality.</p><p><strong>Conclusion: </strong>Severe or critical COVID-19 and a Charlson comorbidity index score of ≥3 were independently associated with high in-hospital mortality. Intensive monitoring and early intervention should be prioritized for high-risk groups to improve clinical outcomes.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148698428","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":"Doxycycline versus azithromycin as combination therapy in the empirical treatment of community-acquired pneumonia in an intensive care unit - A retrospective propensity score-matched cohort study.","authors":"Sin Man Lam, Hoi Ping Shum","doi":"10.1016/j.jmii.2026.07.012","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.07.012","url":null,"abstract":"<p><strong>Introduction: </strong>Community-acquired pneumonia constitutes a significant burden to healthcare systems. While international guidelines recommend beta-lactam plus macrolide in treating severe community-acquired pneumonia, doxycycline instead of macrolide provides antimicrobial activity to macrolide-resistant organisms that are highly prevalent in East Asia and avoids its side effects. Yet, doxycycline's immunomodulatory effect is not as well studied. We investigated the comparative efficacy of doxycycline with azithromycin in the treatment of severe community-acquired pneumonia.</p><p><strong>Methods: </strong>From 1 January 2014 to 31 December 2023, consecutive adult patients with pneumonia or pulmonary sepsis requiring intensive care within 48 h of hospital admission, who received a beta-lactam in combination with either azithromycin or doxycycline were retrospectively reviewed. The two groups were matched by propensity scores and compared for all-cause mortality at day 30.</p><p><strong>Results: </strong>A total of 670 patients were analysed. Streptococcus pneumoniae was the dominant bacteria identified in one fourth of all patients with a bacterial cause. 75% of those cultured were macrolide resistant. Mycoplasma pneumoniae was detected in 0.9% of all patients, while detection of Legionella pneumoniae was 2.8 times higher. Propensity score matching resulted in 250 pairs of patients with balanced covariates. Thirty-day mortality did not differ between groups (21.1% in beta-lactam/azithromycin vs 19.2% in beta-lactam/doxycycline, p = 0.649). A longer duration of azithromycin more than or equal to 3 days did not alter this outcome.</p><p><strong>Conclusions: </strong>Beta-lactam/azithromycin or beta-lactam/doxycycline are viable empirical treatments for severe community-acquired pneumonia despite local resistance patterns. Our result did not support a longer duration of azithromycin over doxycycline.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148702963","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":"Therapeutic strategies for and clinical outcomes in iliopsoas muscle abscess: A systematic review and meta-analysis.","authors":"Wan-Ling Cheng, Chuan-Ju Lin, Shu-Ting Huang, Kuei Chen","doi":"10.1016/j.jmii.2026.07.011","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.07.011","url":null,"abstract":"<p><p>This systematic review and meta-analysis evaluated therapeutic strategies for iliopsoas muscle abscess (IPA). Overall treatment success and mortality rates were 80.4% and 8.3%, respectively, with mortality escalating in complex cases. Modality-specific descriptive estimates showed mortality rates of 4.2% for percutaneous catheter drainage (PCD), 6.2% for open surgical drainage (OSD), and 12.7% for antibiotic monotherapy, with corresponding treatment success rates of 71.4%, 92.0%, and 64.6%, respectively. Length of hospital stay and recurrence were summarized descriptively because of inconsistent definitions and reporting across studies. Staphylococcus species were the most frequently identified pathogens among evaluable pus cultures (38.1%), with S. aureus predominating in primary IPA. In contrast, IPA of gastrointestinal or genitourinary origin was more frequently associated with Enterobacteriaceae. These findings support prompt risk stratification and individualized management based on abscess etiology, morphology, and local microbiology.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148708598","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":"Emerging imipenem resistance in Nocardia infections in Taiwan: a retrospective cohort study at a tertiary teaching hospital.","authors":"Da-Wei Jhou, Chian-Ya Yang, Chong Kei Lao, Nan-Yu Chen, Po-Yen Huang, Shian-Sen Shie, Chih-Hung Chen, Shih-Hong Li, Kuo-Rue Huang, An-Jing Kuo, Wen-Hung Chung, Chih-Jung Chen, Ting-Shu Wu","doi":"10.1016/j.jmii.2026.07.008","DOIUrl":"https://doi.org/10.1016/j.jmii.2026.07.008","url":null,"abstract":"<p><strong>Background: </strong>Nocardia species are emerging pathogens of increasing significance, particularly in immunocompromised hosts. Due to diverse clinical manifestations and resistance patterns, accurate identification is critical. This study characterized species distribution in Taiwan, evaluated identification methodologies, and identified mortality risk factors.</p><p><strong>Methods: </strong>We analyzed 99 Nocardia isolates from 76 patients at a Taiwanese tertiary center (2011-2025). Identification via MALDI-TOF MS and concatenated gene sequencing (16S rRNA, secA1, hsp65) was compared against whole-genome sequencing (WGS). Susceptibility was tested using broth microdilution. Potential mortality-associated variables were first evaluated in univariate analyses, and the final multivariable model was constructed using Firth's penalized logistic regression.</p><p><strong>Results: </strong>N. brasiliensis was most prevalent (27/76; 35.5%), primarily causing cutaneous infections, while N. farcinica (25/76; 32.9%) was linked to pulmonary cases and higher mortality. Firth's penalized logistic regression identified immunosuppressant use (OR 18.44; 95% CI, 3.62-93.89) and higher Charlson Comorbidity Index (CCI) (OR 1.70; 95% CI, 1.23-2.35) as independent predictors of mortality. High rates of imipenem non-susceptibility were observed in N. farcinica (85.7%) and N. cyriacigeorgica (83.3%). In addition, the proportion of imipenem non-susceptible isolates increased significantly during 2020-2025 compared with 2011-2019 (94.1% vs. 67.1%, p = 0.024). Regarding species identification, MALDI-TOF MS demonstrated acceptable performance (PPA = 0.89), whereas concatenated gene sequencing achieved perfect agreement with WGS (PPA = 1.00).</p><p><strong>Conclusions: </strong>Accurate species-level identification is crucial for guiding antimicrobial therapy, especially given the emerging burden of imipenem non-susceptibility in clinically important Nocardia species. Immunosuppressant use and a higher CCI were independently associated with mortality, highlighting the importance of early recognition and appropriate management in high-risk patients. Concatenated multilocus sequence analysis based on 16S rRNA, secA1, and hsp65 provides a practical and accurate alternative to WGS for routine species identification in clinical microbiology laboratories.</p>","PeriodicalId":56117,"journal":{"name":"Journal of Microbiology Immunology and Infection","volume":" ","pages":""},"PeriodicalIF":3.8,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148681187","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}