Acta microbiologica et immunologica Hungarica最新文献

{"title":"Impact of antimicrobial stewardship maturity on resistance and pediatric clinical outcomes: A multicenter cohort study.","authors":"María Eugenia Gallosa Palacios, Israel Barrutia Barreto","doi":"10.1556/030.2026.02825","DOIUrl":"10.1556/030.2026.02825","url":null,"abstract":"<p><p>Antimicrobial resistance (AMR) poses a critical threat to pediatric health, particularly in resource-limited settings. This study aimed to evaluate the association between the maturity of antimicrobial stewardship programs (ASPs) and clinical outcomes in Peruvian hospitals. A multicenter, retrospective cohort study was conducted in three pediatric referral hospitals in Peru, including 1,250 patients hospitalized for bloodstream or urinary tract infections between 2020 and 2023. Multilevel logistic regression models and propensity score matching (PSM) analysis were used to assess risk factors for infections caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and the impact of ASP intervention. The prevalence of ESBL-producing Enterobacteriaceae infection was 32.9% in the three pediatric hospitals of this study. Prior antibiotic use (adjusted Odds Ratio, aOR 5.82) and the presence of a central venous catheter (aOR 2.10) were the main patient-level risk factors. Higher ASP maturity at the hospital level was associated with a lower likelihood of ESBL infection (aOR 0.85). PSM analysis revealed that direct ASP intervention was associated with a significant reduction in hospital length of stay (median of 3 days), 30-day mortality (4.2% difference), and time to appropriate therapy. In conclusion, pediatric AMR in Peru is a severe problem, but investment in and strengthening of ASPs constitute an evidence-based, highly effective strategy with a measurable impact on improving clinical outcomes and hospital efficiency.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"78-85"},"PeriodicalIF":1.5,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146177416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of montelukast combined with inhaled corticosteroids on the airway-gut microbiome and immune regulation in children with asthma.","authors":"DianBiao Fan, YueJin Wu, YuLi Bao, HanYing Xie","doi":"10.1556/030.2026.02777","DOIUrl":"10.1556/030.2026.02777","url":null,"abstract":"<p><p>To evaluate the effect of montelukast combined with inhaled corticosteroids (ICS) on the microbiome-metabolism-immunity axis in children with asthma and to quantify the mediating role of short-chain fatty acids, this single-center, randomized controlled trial enrolled 100 asthmatic children (aged 6-11) who received inhaled corticosteroids with or without montelukast for 12 weeks (n = 50 in the combination group and n = 50 in the ICS-alone group). Microbiome profiles from nasal and fecal samples were assessed via 16S sequencing, and short-chain fatty acids (SCFAs) were quantified by LC-MS/MS. Immune markers (Tregs, cytokines) were measured by flow cytometry and Bio-Plex. Efficacy analyses employed linear mixed-effects models, and SCFA mediation was tested using bootstrap analysis. The combination group demonstrated significantly greater improvements in clinical outcomes including fractional exhaled nitric oxide (FeNO) (β_int = -10.24 ppb, 95% CI -16.37 to -4.11, P = 0.001), Childhood Asthma Control Test (C-ACT) score (β_int = +1.83, P < 0.05) and FEV1% (β_int = +1.87, P < 0.05) compared to ICS alone. Microbiome analysis revealed enhanced α-diversity in both nasal and fecal samples (interaction P < 0.01) with significant community structure changes (PERMANOVA interaction P_perm < 0.01). Specific genus-level alterations included reduced nasal Moraxella and Haemophilus (logFC < 0, q < 0.10) and increased fecal SCFA-producing taxa including Faecalibacterium, Roseburia, Subdoligranulum, Agathobacter, and Eubacterium hallii group (logFC > 0, q < 0.10). The combination therapy also led to elevated fecal and serum SCFA levels (β_int > 0, P < 0.01), enhanced regulatory T cell (Treg) and IL-10 responses, and suppressed Th2 cytokines (IL-4/IL-5/IL-13). Mediation analysis confirmed SCFAs partially mediated FeNO improvement, with proportions of 30.0% for total SCFAs and 37.5% for butyrate (ACME and ADE both negative, P < 0.01). The combination of montelukast and inhaled corticosteroids was superior to inhaled corticosteroids alone, providing clinical benefits that were linked to favorable remodeling of the airway-gut microbiome and enhanced Treg/IL-10 immunity. This improvement was partially mediated by short-chain fatty acids, with a comparable safety profile.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"223-234"},"PeriodicalIF":1.5,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146103580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gut microbiota dysbiosis and bone mineral density in hemodialysis patients: The mediating role of immune-metabolic pathways and clinical implications for nursing care.","authors":"Xunan Cheng, Shutong Pu, Zhiying Wang, Xiaoyan Zhang, Manqi Zuo, Qiangguo Ao, Zhen Wu","doi":"10.1556/030.2026.02826","DOIUrl":"10.1556/030.2026.02826","url":null,"abstract":"<p><p>The relationship between gut microbiota dysbiosis and bone mineral density (BMD) in hemodialysis patients, mediated through immune-metabolic pathways, remains to be fully elucidated. In this single-center prospective cross-sectional study, 165 maintenance hemodialysis patients were included to evaluate the independent association between gut microbiota composition and BMD, quantify the mediating roles of immune markers and gut-derived metabolites, and assess the effect modification by nursing-modifiable factors. Fecal samples underwent 16S rRNA sequencing and functional prediction. Inflammatory cytokines (IL-6, TNF-α), gut-derived metabolites (indoxyl sulfate, butyrate), and BMD via dual-energy X-ray absorptiometry (DXA) were measured. Gut microbiota community structure significantly differed across BMD tertiles (R2 = 0.033, P = 0.003). After full adjustment, principal coordinate 1 (PCoA-PC1, beta-diversity) was negatively associated with femoral neck BMD, while the Shannon diversity index showed a positive association (both P < 0.05). We identified 15 differentially abundant genera between high and low BMD groups. Functional prediction revealed short-chain fatty acid pathways were positively associated with BMD, while indole/p-cresol pathways showed negative associations. Mediation analysis demonstrated that immune markers and gut-derived metabolites collectively explained 45.71% of the microbiota-BMD relationship. Nursing factors significantly modified this association, with the negative relationship strengthened by low fiber intake, severe constipation, proton pump inhibitor use, and inadequate dialysis (Kt/V < 1.4). In conclusion, gut microbiota dysbiosis is independently associated with lower BMD in hemodialysis patients, partially mediated through immune-inflammatory pathways and gut-derived metabolites. Dietary fiber optimization, constipation management, prudent proton pump inhibitor prescribing, and dialysis adequacy represent actionable nursing targets to mitigate gut-mediated bone loss in this vulnerable population.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"20-32"},"PeriodicalIF":1.5,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146103547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of fungaemia caused by Trichosporon species in South-Eastern Europe.","authors":"Sotirios Varlamis, Ilias Pessach, Maria-Anna Kyriazidi, Eleni Gavriilaki, Maria Mavridou, Stella Mitka, Maria Chatzidimitriou, Timoleon-Achilleas Vyzantiadis","doi":"10.1556/030.2026.02852","DOIUrl":"10.1556/030.2026.02852","url":null,"abstract":"<p><p>The incidence of fungaemia caused by rare yeasts, particularly Trichosporon species, is rising globally, posing diagnostic and therapeutic challenges-especially in immunocompromised patients. This systematic review aims to analyse the epidemiology, diagnostic approaches, antifungal susceptibility, and clinical outcomes of Trichosporon fungaemia (TF) in South-Eastern Europe, including Turkey. A comprehensive search was conducted in PubMed and Scopus in August 2025. A total of 59 cases from 12 studies were identified, with Trichosporon asahii being the most prevalent species (86.4%). Cases originated from Turkey (79.7%), Greece (18.6%), and Croatia (1.7%). Diagnostic techniques varied, with phenotypic methods still widely used. MALDI-TOF MS and DNA sequencing were mainly applied as confirmatory methods. Haematologic disorders were the most frequently reported underlying conditions among the patients. Sixteen breakthrough fungaemia cases-occurring despite empirical or prophylactic antifungal therapy-were identified. Although rare, TF represents a severe infection with significant mortality in South-Eastern Europe. Early and accurate species identification-facilitated by advanced diagnostic tools-is crucial for effective management. In addition to diagnostic difficulties, treatment is also challenging. Voriconazole appears to be the preferred antifungal agent, even in breakthrough fungaemia cases. Enhanced awareness, routine use of molecular diagnostics, and ongoing epidemiological monitoring are essential to improve patient outcomes.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"143-156"},"PeriodicalIF":1.5,"publicationDate":"2026-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146049911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gut microbiota-based prediction of clinical response to sublingual immunotherapy in Artemisia pollen-induced allergic rhinitis: A prospective cohort study.","authors":"Fei Wang, Jinjin Yang, Liming Bao, Bat Jin","doi":"10.1556/030.2026.02831","DOIUrl":"10.1556/030.2026.02831","url":null,"abstract":"<p><p>The gut microbiota plays a crucial role in modulating mucosal immunity and allergic responses, yet its predictive value for sublingual immunotherapy (SLIT) outcomes remains underexplored in Artemisia pollen-induced allergic rhinitis (AR). In this single-center prospective cohort study, 204 adults with Artemisia pollen-induced AR underwent baseline stool collection before initiating standardized SLIT. Gut microbiota was analyzed using 16S rRNA sequencing of the V3-V4 region, with prespecified features including Shannon diversity index, composite abundance of butyrate-producing bacteria (Faecalibacterium, Roseburia, Eubacterium rectale group), and Prevotella-to-Bacteroides (P/B) ratio. Clinical response was defined as ≥30% reduction in combined symptom-medication score (CSMS) during the peak pollen season. We developed three prediction models: Model A (clinical variables only), Model B (clinical variables plus microbiota features), and Model C (parsimonious model via L1 regularization). The response rate was 54.41% (111/204). In multivariable analysis, all three microbiota features independently predicted treatment response: butyrate-producing bacteria (OR = 1.59, q = 0.006), P/B ratio (OR = 1.43, q = 0.020), and Shannon diversity (OR = 1.33, q = 0.046). Model B demonstrated superior discrimination compared to Model A (AUC 0.79 vs 0.71, ΔAUC = 0.08, P = 0.021), with improved calibration (intercept α = -0.03, slope β = 0.98) and significant net reclassification improvement (NRI = 0.36, P = 0.002). Decision curve analysis confirmed greater net benefit across clinically relevant threshold probabilities. The parsimonious Model C maintained good performance (optimism-corrected AUC = 0.78) with 77.48% sensitivity and 72.04% specificity. Baseline gut microbiota characteristics, particularly butyrate-producing bacterial abundance, microbial diversity, and Prevotella/Bacteroides community structure, significantly predict SLIT response in Artemisia pollen-induced AR and provide substantial incremental value over conventional clinical parameters. These findings support the integration of gut microbiota assessment into pretreatment stratification algorithms for allergen immunotherapy.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"33-44"},"PeriodicalIF":1.5,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Public health challenges of tuberculosis in urban slums: Prevalence and drug resistance in Punjab, Pakistan.","authors":"Muhammad Nauman, Muhammad Shafique, Bilal Aslam, Mohsin Khurshid","doi":"10.1556/030.2026.02776","DOIUrl":"10.1556/030.2026.02776","url":null,"abstract":"<p><p>Tuberculosis (TB) control remains severely challenged in Pakistan, with urban slum populations bearing a disproportionate burden due to pronounced socioeconomic disparities. The emergence of multidrug-resistant TB (MDR-TB) poses a critical public health threat; however, community-level data from these high-transmission settings remain limited, obscuring the true scale of the epidemic. A cross-sectional study involving 3,317 individuals was conducted across the urban slum of six districts in Punjab, Pakistan between June 2024 and May 2025. Sputum samples were analyzed using smear microscopy, GeneXpert MTB/RIF, and comprehensive drug susceptibility testing (DST). Sociodemographic and clinical data were collected to assess potential risk factors. The prevalence of Mycobacterium tuberculosis (MTB) infection confirmed by GeneXpert was 17.0% (564/3,317), significantly higher than the 12.8% detected by smear microscopy. Initial molecular testing identified rifampicin resistance in 40.2% (227/564) of MTB-positive cases, with 39.0% (220/564) fulfilling the criteria for MDR-TB. The MDR-TB burden was markedly higher among retreatment cases (68.1%) compared with new cases (29.8%) and exhibited significant geographic clustering, with prevalence exceeding 53% in Lahore and Kasur. Smoking emerged as the most significant risk factor, observed in 73.8% of MTB-positive individuals (P < 0.001). Among rifampicin-resistant isolates subjected to extended DST, resistance rates were 96.9% for isoniazid, 100% for rifampicin, 46.3% for ofloxacin, 4.4% for amikacin, 22.9% for kanamycin, and 8.4% for capreomycin. The prevalence of MDR-TB in the urban slums of Punjab was alarmingly higher than national and global estimates. These findings necessitate an urgent need for expanded molecular diagnostics, active case-finding, and targeted public health interventions in these marginalized communities. Without immediate and coordinated action, urban slums risk becoming focal points for the accelerated emergence of untreatable TB.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"101-109"},"PeriodicalIF":1.5,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146008812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mutations related to rifampicin and isoniazid resistance in Mycobacterium tuberculosis strains in Ankara, Turkey.","authors":"Oguz Ari, Riza Durmaz, Ahmet Arslanturk, Sedat Vezir","doi":"10.1556/030.2026.02818","DOIUrl":"10.1556/030.2026.02818","url":null,"abstract":"<p><p>The identification of mutations associated with drug resistance is of paramount importance for the rapid detection of drug-resistant Mycobacterium tuberculosis strains. The objective of this study was to identify the mutations responsible for conferring resistance to rifampicin (RIF) and isoniazid (INH) in M. tuberculosis. A total of 84 drug-resistant M. tuberculosis strains including 41 multidrug-resistant (MDR) strains, 37 INH-resistant, RIF-susceptible strains, and 6 RIF-resistant, INH-susceptible strains were analyzed. The 86 M. tuberculosis strains were isolated from clinical samples, between 2022 and 2023 in Ankara, Turkey. PCR amplification and sequencing of rpoB, katG and inhA genes were performed to detect mutations. In the 47 RIF-resistant strains, the predominant mutation in rpoB was S450L observed in 40 of 47 strains (85%), followed by H445Y detected in two strains (4.3%). The Q432K/P, M434I, D435Y, T444I, H445G, S450W, and S450F mutations were identified in one strain each. The S315T mutation in the katG gene was identified in 60 of the 78 INH-resistant strains (76.9%). The rate of mutation -15C>T in inhA was 29.5% (23/78). Both S315Y and -15C>T mutations were detected in six strains (7.7%). This study provided comprehensive information regarding the genetic background of drug-resistant tuberculosis in terms of prevalent mutations responsible for RIF and INH resistance. These findings contribute to develop more sensitive qPCR tests that target mutations for the rapid detection of drug-resistant TB.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"95-100"},"PeriodicalIF":1.5,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145996938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative analysis of two lateral flow immunoassays for carbapenemase detection in Klebsiella pneumoniae and Pseudomonas aeruginosa.","authors":"Serap Süzük Yıldız, Özge Nur Arıcasoy, Zekiye Bakkaloğlu, Özlem Ünaldı, Can Hüseyin Hekimoğlu, Ayşe Semra Güreser, İpek Mumcuoğlu, Tuba Dal","doi":"10.1556/030.2026.02859","DOIUrl":"10.1556/030.2026.02859","url":null,"abstract":"<p><p>Accurate and rapid identification of carbapenemase-producing Gram-negative bacteria is essential for appropriate antimicrobial therapy and infection control. This study compared the diagnostic performance of two multiplex lateral flow immunoassays, the NG-Test CARBA 5 (NG) and a Colloidal Gold Immunoassay (CGI), for the detection of major carbapenemases in clinical isolates of Klebsiella pneumoniae and Pseudomonas aeruginosa. A total of 100 non-duplicate carbapenem-resistant isolates collected in 2024 were included. An in-house polymerase chain reaction assay targeting blaKPC, blaNDM, blaVIM, blaIMP, and blaOXA-48-like genes served as the reference standard.Overall, the NG assay demonstrated higher sensitivity than the CGI assay, while both tests showed excellent specificity. For OXA-48-like enzymes, both assays exhibited 100% specificity and 89.6% sensitivity. Detection of NDM was more sensitive with NG (96.9%) than with CGI (87.7%), whereas both maintained 100% specificity. For KPC detection, NG achieved 100% sensitivity, while CGI showed a markedly lower sensitivity (73.7%). Diagnostic performance was generally superior in K. pneumoniae compared with P. aeruginosa, and both assays showed reduced sensitivity in isolates co-harboring multiple carbapenemase genes.These findings indicate that although both lateral flow assays are rapid and practical tools for routine laboratory use, their performance may vary depending on the carbapenemase type and local epidemiology. Molecular confirmation remains essential, particularly in settings with a high prevalence of multiple carbapenemase-producing isolates.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"54-58"},"PeriodicalIF":1.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145987738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resistome and phylogenomic analysis of trimethoprim-sulfamethoxazole-resistant Stenotrophomonas maltophilia complex isolates obtained from Bulgarian hematopoietic stem cell transplant recipients.","authors":"Tanya Strateva, Denis Niyazi, Temenuga Stoeva, Slavil Peykov","doi":"10.1556/030.2026.02794","DOIUrl":"10.1556/030.2026.02794","url":null,"abstract":"<p><p>The present study aimed to investigate the resistome of four trimethoprim-sulfamethoxazole (SXT)-resistant Stenotrophomonas maltophilia complex (Smc) isolates from Bulgarian hematopoietic stem cell transplantation (HSCT) recipients and to subject them to phylogenomic analysis involving all sul1-positive strains of the identified species with available genomes worldwide. Preliminary identification by MALDI-TOF mass spectrometry determined all four isolates as S. maltophilia. The sources of isolation were stools (SM175, SM176, and SM179) and urine (SM178). SM176 and SM178 also showed high-level levofloxacin resistance. All isolates demonstrated in vitro susceptibility to minocycline and cefiderocol. Whole-genome sequencing (WGS) assigned SM175, SM176, and SM178 as Stenotrophomonas forensis. Two types of class 1 integrons were detected in the four isolates, namely SM175 and SM179 carried empty integrons, whereas SM176 and SM178 carried a gene cassette (3,748 bp in length) consisting of aac6'-Ib-cmlB-blaOXA-9. Alignment against public databases revealed that this cassette has not been found in Stenotrophomonas species so far, but it was present in Pseudomonas aeruginosa and Enterobacterales. Phylogenomic analysis of our assembled sequences, together with all 26 sul1-positive S. maltophilia and S. forensis genomes, indicated that S. maltophilia SM179 was not part of any S. maltophilia cluster. SM175, SM176, and SM178 were closely related (differences of 35-101 SNPs). To the best of our knowledge, this is the first report of SXT-resistant Smc isolates from post-HSCT patients with hematological malignancies in Bulgaria, which presents WGS-based resistome and phylogenomic analyses. We also report on the first sul1-containing S. forensis clinical isolates. Our findings reveal high global heterogeneity of sul1-positive S. maltophilia.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"59-70"},"PeriodicalIF":1.5,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145987814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of ceftazidime-avibactam resistant blaKPC-35-harbouring Klebsiella pneumoniae ST15 from bloodstream infection.","authors":"Yihui Gong, Lingfei Wang, Qiao Wang, Huijie Yue, Ying Wang, Tao Li, Guohua Zhou, Xuejiao Liu","doi":"10.1556/030.2026.02845","DOIUrl":"10.1556/030.2026.02845","url":null,"abstract":"<p><p>The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a significant challenge globally. This study reports on a ceftazidime-avibactam resistant KPC-35 producing K. pneumoniae strain from a patient with cerebral hemorrhage undergoing ceftazidime-avibactam (CZA) treatment. In this study, three K. pneumoniae strains were isolated from blood samples of a patient after intracerebral hemorrhage. Broth microdilution, checkerboard assays, and time-kill assays were employed to evaluate antimicrobial susceptibility and combination regimens. Whole-genome sequencing (WGS) was used to investigate the genetic characteristics of the three K. pneumoniae strains. The results showed that, K. pneumoniae KP29870 strain belonged to ST15, it was KPC-35 positive and exhibited a 16-fold higher minimum inhibitory concentration (MIC) of CZA (32 vs 1-2 mg L-1) but significantly lower MICs of imipenem (2 vs ≥ 16 mg L-1) and meropenem (1 vs ≥ 16 mg L-1), compared to the other two K. pneumoniae strains, that harboured KPC-2. CZA resistant K. pneumoniae remained highly susceptible to aztreonam-avibactam (MIC 0.03/4 mg L-1). The single base mutation (T503C) resulted in the substitution of leucine with proline at Ambler amino acid position 169 (L169P), corresponding to an evolution from blaKPC-2 to blaKPC-35. Checkerboard and time-kill assays demonstrated synergistic antibacterial effects for CZA combined with imipenem, meropenem, or with aztreonam against KPC-35 positive K. pneumoniae. This is the first report in China of a K. pneumoniae ST15 strain harboring blaKPC-35 emerging from a blaKPC-2-positive ancestor during CZA treatment. The new β-lactamase inhibitor combination such as aztreonam-avibactam monotherapy or CZA combined with carbapenems or with aztreonam represents promising treatment strategies against such KPC mutants. We recommend prompt susceptibility testing and KPC genotyping if resistance emergence is suspected during CZA therapy.</p>","PeriodicalId":7119,"journal":{"name":"Acta microbiologica et immunologica Hungarica","volume":" ","pages":"45-53"},"PeriodicalIF":1.5,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145964737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}