ASM case reports最新文献

{"title":"Severe chronic UTI sustained by clinically undetected intracellular <i>Escherichia coli</i> in a pediatric patient.","authors":"Arthika Manoharan, Naveen Wijekoon, Greg Whiteley, Theerthankar Das Ashishkumar, Neftali Flores-Rodriguez, Slade O Jensen, Bill Söderström, Kate H Moore, Jim Manos, Ben J Marais, Aniruddh Deshpande","doi":"10.1128/asmcr.00077-25","DOIUrl":"10.1128/asmcr.00077-25","url":null,"abstract":"<p><strong>Background: </strong>The presence of intracellular bacterial communities (IBCs) in the urothelium has been well documented in adults with chronic urinary tract infections (UTIs), but its long-term persistence going undetected in a severely symptomatic adolescent has not been reported.</p><p><strong>Case summary: </strong>We present the case of a 14-year-old girl suffering from debilitating chronic UTI symptoms and associated urinary incontinence for many years. Multiple antibiotic courses provided only temporary relief, with positive <i>Escherichia coli</i> cultures recurring promptly after each treatment cycle. A recently conducted cystoscopy (after >6 years of persistent symptoms) revealed widespread squamous metaplasia of the bladder wall, and enhanced urinary analysis identified extensive intracellular bacterial (<i>E. coli</i>) communities in exfoliated urothelial cells. These intracellular bacterial communities persisted even when the urine became transiently culture negative on antibiotic treatment. Evidence from confocal microscopy demonstrated extensive intracellular <i>E. coli</i>, which may serve as a bacterial reservoir that seeds urinary reinfection when antibiotics are ceased. Persistent intracellular bacteria were not detected by routine urine microscopy and culture. Analysis of urinary cytokines suggested chronic inflammation of the bladder wall, driven by persistent bacterial infection, as the potential cause for the unrelenting symptoms.</p><p><strong>Conclusion: </strong>This is the first report demonstrating long-term undetected IBC in a severely symptomatic child with chronic UTI. It underscores the need to learn more about intracellular bacteria and urinary tract biofilms that are protected from antibiotics and host immunity. IBC reservoirs seem to drive bladder wall inflammation, exacerbating clinical symptoms and increasing the risk of long-term adverse sequelae.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12772279/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145919581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Mycobacterium wolinskyi</i> as an emerging cause of pacemaker pocket infection and lead endocarditis: a case report and genomic characterization.","authors":"Julie Dom, Reinoud Cartuyvels, Anne Bruggemans, Timo Froyen, Petra Hilkens, Koen Magerman, Steven Martens, Britta Van Meensel, Jozef Dingemans","doi":"10.1128/asmcr.00146-25","DOIUrl":"10.1128/asmcr.00146-25","url":null,"abstract":"<p><strong>Background: </strong>Rapidly growing non-tuberculous mycobacteria (NTM) are increasingly recognized as causative agents in healthcare-associated infections. <i>Mycobacterium wolinskyi</i>, first described in 1999, has been associated with post-traumatic and post-operative wound infections.</p><p><strong>Case summary: </strong>We report a case of <i>M. wolinskyi</i> pacemaker pocket infection and lead endocarditis in a 73-year-old man, 3 weeks after implantable cardioverter-defibrillator (ICD) implantation. Initial culture from a superficial pocket swab yielded slow-growing, white colonies on chocolate agar, and the strain was identified by MALDI-TOF as <i>M. wolinskyi</i>. However, the 16S rRNA, <i>hsp65</i>, <i>rpoB,</i> and <i>recA</i> sequences were identical to those of the unofficially described <i>M. jacuzzi</i> species but different from the corresponding sequences of the <i>M. wolinskyi</i> ATCC 700010 reference strain, which showed an average nucleotide identity (ANI) of 97.49% upon whole genome comparison. Therapy consisted of ICD removal, surgical debridement of the pocket, and prolonged combination therapy with oral moxifloxacin and co-trimoxazole, with favorable clinical outcome.</p><p><strong>Conclusion: </strong>This case demonstrates that our strain of <i>M. wolinskyi</i> could be an emerging pathogen in device-associated infections. The case highlights the diagnostic limitations of routine methods and emphasizes the role of 16S sequencing and whole genome sequencing in accurate taxonomic classification of NTM species. Broader genomic surveillance is warranted to understand the epidemiology and taxonomy of this rapidly growing NTM.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12772322/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145919756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unusual fungemia caused by non-<i>marneffei Talaromyces</i> in an immunocompetent host.","authors":"Eun Jeong Won, Jina Lee, Jae Suk Baek, Seunghwan Seol, Sookja Park, Hyang Burm Lee, Heungsup Sung, Mi-Na Kim","doi":"10.1128/asmcr.00096-25","DOIUrl":"10.1128/asmcr.00096-25","url":null,"abstract":"<p><strong>Background: </strong><i>Talaromyces</i>, a genus phylogenetically related to <i>Penicillium</i>, is saprophytic except for <i>Talaromyces marneffei</i>. Herein, we describe the first documented case of fungemia caused by <i>Talaromyces tumuli</i>.</p><p><strong>Case summary: </strong>A case without overt predisposing conditions had suffered from recurrent bacteremia of various causes over the past 3 years and was admitted due to prolonged fever despite antimicrobial therapy this time. Three sets of blood cultures were negative at admission. On hospitalization day (HD) 5, two sets of blood cultures obtained via a subclavian venous catheter (SVC) became positive for hyphae in aerobic vials only with detection time of 67 h, respectively. Subculture of positive blood culture vial to Sabouraud dextrose agar yielded blue-green colonies without production of red pigments. Microscopic examination showed biverticillate <i>Penicillium</i>-like conidiophores and species identification using the MALDI Biotyper sirius System (Bruker) resulted in a first-rank match to <i>Talaromyces funiculosus</i> with non-reliable identification score of 1.63. Sequencing of the regions of <i>ITS, BenA, CaM</i>, and <i>RPB2</i> genes identified it as <i>T. tumuli</i>. Subsequent blood cultures remained positive for it on six episodes until removal of the SVC on HD 18, despite voriconazole treatment.</p><p><strong>Conclusion: </strong>This case was the first case of a central venous catheter-associated bloodstream infection caused by <i>T. tumuli</i>.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584170/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145545000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bad to the bone: <i>Candida (Candidozyma) auris</i> vertebral osteomyelitis treated with combination antifungal therapy followed by a novel long-acting echinocandin.","authors":"Lauryn B Jenkins, Robbie L Christian, Boris A Karaman, Mahmoud A Ghannoum, Khalid M Dousa","doi":"10.1128/asmcr.00114-25","DOIUrl":"10.1128/asmcr.00114-25","url":null,"abstract":"<p><strong>Background: </strong><i>Candida auris</i> is an emerging multidrug-resistant yeast associated with healthcare-associated infections and high mortality. Vertebral osteomyelitis due to <i>Candida auris</i> is rare and challenging to treat due to limited data on antifungal bone penetration, prolonged treatment duration, and resistance to multiple antifungal classes. Long-acting agents such as rezafungin may offer promising outpatient options, though clinical experience remains limited.</p><p><strong>Case summary: </strong>A 70-year-old male developed vertebral osteomyelitis/discitis at T3-T4 due to <i>Candida auris</i>, following multiple catheter-related bloodstream infections and <i>C. auris</i> candidemia. Initial treatment included dual antifungal therapy with liposomal amphotericin B and micafungin, selected based on <i>in vitro</i> susceptibility and preclinical synergy data. Therapy was complicated by severe electrolyte disturbances, requiring early discontinuation of amphotericin B. He transitioned to rezafungin and completed nearly 3 months of treatment at home, contributing to a total of 6 months of antifungal therapy in alignment with IDSA guidelines. Rezafungin was generally well tolerated, with only mild hypokalemia and episodic migraine-like symptoms. The patient achieved complete clinical recovery with the resolution of symptoms and normalization of inflammatory markers. No relapse was reported at the 6-month follow-up.</p><p><strong>Conclusion: </strong>This case highlights the complexity of managing invasive <i>Candida auris</i> osteomyelitis and underscores the utility of dual antifungal combination therapy to enhance efficacy and potentially prevent the development of resistance during the intensive phase of treatment. It also demonstrates the feasibility of using rezafungin as an option for long-term outpatient management. Given the limited clinical experience with combination therapy and rezafungin use, further data are needed to inform standardized treatment approaches.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584175/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Bartonella</i>-associated glomerulonephritis without endocarditis in a renal transplant recipient.","authors":"Grace A Schaack, Rene Bulnes, Deborah Jebakumar, Allen R Hendricks, Andrew E Clark","doi":"10.1128/asmcr.00092-25","DOIUrl":"10.1128/asmcr.00092-25","url":null,"abstract":"<p><strong>Background: </strong><i>Bartonella henselae</i> is a fastidious gram-negative rod that can cause systemic disease in immunocompromised patients. Infection may be complicated by glomerulonephritis, often in the setting of culture-negative infective endocarditis. The histologic pattern of <i>Bartonella</i>-associated glomerulonephritis is variable and often difficult to distinguish from non-infectious causes of glomerulonephritis by histopathology. Prompt, accurate diagnosis is further complicated by the poor sensitivity of routine culture methods for the detection of <i>B. henselae</i>, and serology or adjunctive molecular testing is typically required for microbiologic diagnosis.</p><p><strong>Case summary: </strong>A middle-aged male renal transplant recipient was admitted to our hospital with fever, nausea, vomiting, diarrhea, and laboratory evidence of acute kidney injury. A thorough infectious disease work-up revealed markedly elevated <i>B. henselae</i> immunoglobulin G and immunoglobulin M titers and significant exposures to cats and fleas. A biopsy of the renal allograft revealed crescentic glomerulonephritis with immune complex deposition. No definitive evidence of infective endocarditis was found. The patient was started on renal replacement therapy and treated for disseminated bartonellosis with doxycycline and rifabutin.</p><p><strong>Conclusion: </strong>The diagnosis of <i>Bartonella</i>-associated glomerulonephritis in immunocompromised patients can be challenging from both the clinical and histopathologic perspectives. A high degree of clinical suspicion in patients with relevant risk factors is important for prompt diagnosis and treatment. Regardless of the presence or absence of typical signs and symptoms of cat scratch disease and/or infective endocarditis, <i>Bartonella</i> spp. should be included in the differential diagnosis of glomerulonephritis in solid-organ transplant recipients and other immunocompromised patients with cats or other relevant exposures.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584172/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Tropheryma whipplei</i> native valve endocarditis diagnosed by sequencing of microbial cell-free DNA in plasma.","authors":"Peter M Rabinowitz, Ritika Walia, Paul Pottinger, Joshua A Lieberman","doi":"10.1128/asmcr.00070-25","DOIUrl":"10.1128/asmcr.00070-25","url":null,"abstract":"<p><strong>Background: </strong>Endocarditis is an important manifestation of extra-intestinal Whipple's disease. The etiologic agent, the bacterium <i>Tropheryma whipplei</i>, cannot be cultivated in clinical laboratories, making the diagnosis of this culture-negative infection challenging. Molecular methods have emerged as useful adjuncts for the diagnosis of culture-negative endocarditis.</p><p><strong>Case summary: </strong>A 67-year-old male was seen in an infectious disease clinic for evaluation of a possible infectious etiology of chronic musculoskeletal pain with exercise intolerance. He had a history of an embolic stroke 2 years earlier, echocardiographic evidence of aortic valve thickening, and multiple negative blood cultures. Following an evaluation that included serology and extended incubation blood culture, plasma was sent for metagenomic sequencing of microbial cell-free DNA, which was positive for <i>Tropheryma whipplei</i>.</p><p><strong>Conclusion: </strong>The patient's musculoskeletal complaints and his exercise intolerance resolved after treatment with ceftriaxone and trimethoprim-sulfamethoxazole. To our knowledge, this is the first report of <i>T. whipplei</i> native valve endocarditis diagnosed by metagenomic sequencing.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584185/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic analysis of a <i>Neisseria meningitidis</i> patient isolate causing a false-positive result in the Abbott Alinity m STI, Sweden: a case report.","authors":"Björn Herrmann, Andreas Sälléber, Rene Kaden","doi":"10.1128/asmcr.00143-25","DOIUrl":"10.1128/asmcr.00143-25","url":null,"abstract":"<p><strong>Background: </strong>Diagnostics of sexually transmitted infections, such as <i>Neisseria gonorrhoeae</i> (NG), are often performed using high-volume test systems, often in combination with other targets. This report examines the occurrence of two false-positive NG results from pharyngeal samples in the Abbott Alinity m STI assay, cleared by the Food and Drug Administration.</p><p><strong>Case summary: </strong>Analysis of pharyngeal samples from two men who have sex with men was positive for NG in the Abbott Alinity m STI assay, but negative upon confirmation testing with the Cepheid Xpert CT/NG assay. A pharyngeal culture isolate was obtained from one of the two men. The isolate tested negative for being NG in four different commercial nucleic acid amplification tests. A laboratory-developed PCR based on two targets gave inconclusive results, with positive detection for the <i>opa</i> gene but no detection for the <i>porA</i> gene. The isolate was identified as <i>Neisseria meningitidis</i> (NM) in MALDI-TOF analysis. Whole-genome sequencing revealed 322 diverse virulence genes, of which 314 were typical for NM and 8 for NG. Phylogenetic analysis showed a taxonomic delineation for NM.</p><p><strong>Conclusion: </strong>Confirmatory tests with alternative targets are essential for accurate analysis of NG, especially in low-prevalence settings. Evaluation of diagnostic tools to ensure accurate detection of NG is also needed.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584176/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Disseminated <i>Lomentospora prolificans</i> infection in a neutropenic patient with acute monocytic leukemia: a clinical and diagnostic challenge.","authors":"Sierra Amaya, Giancarlo Giovannini-Sanguineti, Corina Lopez, Carolyn D Alonso, Stefan Riedel","doi":"10.1128/asmcr.00093-25","DOIUrl":"10.1128/asmcr.00093-25","url":null,"abstract":"<p><strong>Background: </strong><i>Lomentospora prolificans</i> is an opportunistic fungal pathogen associated with significant morbidity and mortality in immunocompromised individuals. Its intrinsic resistance to most antifungal agents poses challenges in clinical management, particularly in patients with hematological malignancies.</p><p><strong>Case summary: </strong>Herein, we report the case of a 60-year-old male with recently diagnosed acute monocytic leukemia who developed a disseminated <i>L. prolificans</i> infection during induction chemotherapy. Despite standard prophylactic antimicrobials, the patient experienced febrile neutropenia, progressive pulmonary findings, and neurological complications, culminating in disseminated fungal infection. Blood cultures confirmed the diagnosis, and antifungal therapy was promptly expanded. However, the infection progressed rapidly, and the patient died despite aggressive therapeutic interventions.</p><p><strong>Conclusion: </strong>This case highlights the complexities of diagnosing and treating <i>L. prolificans</i> infections in profoundly immunosuppressed patients. It underscores the importance of heightened clinical suspicion, early recognition, aggressive management, and the need for continued development of novel antifungal agents and diagnostic techniques.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584181/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From detection to decision: how laboratory testing and reporting strategies can shape management of carbapenemase-producing <i>Enterobacterales</i> infections.","authors":"Shannon G Murphy, Patricia J Simner","doi":"10.1128/asmcr.00139-25","DOIUrl":"10.1128/asmcr.00139-25","url":null,"abstract":"<p><p>Antimicrobial resistance mediated by carbapenemases significantly complicates treatment options. A case report by Morelan et al. (ASM Case Reports 1:e00094-25, 2025, https://doi.org/10.1128/asmcr.00094-25) illustrates how delayed recognition of <i>Klebsiella pneumoniae</i> carbapenemase (KPC) production in an <i>Escherichia coli</i> urinary tract infection resulted in suboptimal cefepime therapy, despite <i>in vitro</i> susceptibility. This case underscores the urgent need for clinical laboratories to implement on-site carbapenemase testing, as recommended by the Infectious Diseases Society of America and the Clinical and Laboratory Standards Institute (CLSI). Timely detection of KPC, coupled with reporting strategies for cefepime susceptibility results (suppression or editing results as resistant) in carbapenemase producers, may have facilitated earlier administration of a more appropriate antimicrobial and prevented recurrent infections and readmissions. In this commentary, we highlight recent updates to CLSI guidance for carbapenemase testing and antimicrobial susceptibility reporting strategies. Using this case report as an example, we outline the potential impact of these strategies on patient management and outcomes, further emphasizing the role of the clinical microbiology laboratory in antimicrobial stewardship.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584174/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly pathogenic avian influenza A H5N1 virus infection in an immunocompromised domestic cat.","authors":"Chi Chen, Akhila Naru, Vineetha Reddy Mareddy, Saraswathi Lanka, Colleen Olmstead, Vanessa Revindran-Stam, Megan Sherman, Heather Yee, Natara Loose, Martha A Delaney, Miranda D Vieson, Ying Fang","doi":"10.1128/asmcr.00134-25","DOIUrl":"10.1128/asmcr.00134-25","url":null,"abstract":"<p><strong>Background: </strong>Highly pathogenic avian influenza (HPAI) H5N1 viruses of clade 2.3.4.4b have recently caused widespread outbreaks in mammals, including domestic cats that live closely with humans and other animals. In-depth molecular and pathological characterizations of naturally infected cats are urgently needed for developing better strategies to prevent interspecies transmission and further spreading of these viruses.</p><p><strong>Case summary: </strong>In this case report, we characterized a unique case of HPAI H5N1 virus infection in an immunocompromised domestic cat. The pet animal was a diabetic cat with a history of feline infectious peritonitis (FIP). In early 2025, the cat developed acute fever and rapidly worsening respiratory distress and liver dysfunction despite antibiotic treatment. Due to severe clinical deterioration, the cat was euthanized. Postmortem examination revealed severe bronchointerstitial pneumonia, hepatic and lymphoid necrosis, bone marrow degeneration, and mild lymphohistiocytic meningitis. H5N1 viral RNA/antigens were specifically detected in the lung, brain, urine, or lymphoid tissues. Whole-genome sequencing and phylogeny analysis identified that the virus belongs to influenza clade 2.3.4.4b (B3.13 subgroup), closely related to HPAI H5N1 strains that are currently circulating in domestic cats and cattle. The source of infection for this particular cat might be linked to a fomite/environmental transmission route.</p><p><strong>Conclusion: </strong>The lethal HPAI H5N1 virus infection in an immunocompromised cat highlights the need for developing an improved prevention plan for pet animals. Clinicians should consider the possibility of H5N1 virus infection in cats with similar acute respiratory or neurologic signs, particularly in animals with chronic illness.</p>","PeriodicalId":521101,"journal":{"name":"ASM case reports","volume":"1 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12584193/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145544995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}