Indian Journal of Medical Microbiology最新文献

{"title":"Twice isolated, not twice ignored: Bacillus cereus catheter-related bloodstream infection in a haemodialysis patient.","authors":"Atish Mohapatra, Shirsha Mondal, A S Girish, Neelam Devi Maravi, Pragya Agarwala","doi":"10.1016/j.ijmmb.2026.101321","DOIUrl":"https://doi.org/10.1016/j.ijmmb.2026.101321","url":null,"abstract":"<p><p>A 53-year-old man with chronic kidney disease on maintenance haemodialysis via a right internal jugular tunnelled catheter (permcath) presented with recurrent fever during dialysis sessions. Paired blood cultures from the catheter and peripheral vein yielded Bacillus cereus. As the organism is frequently regarded as a contaminant, repeat paired cultures were obtained, which again grew B. cereus susceptible to vancomycin and gentamicin. Catheter-drawn cultures flagged positive earlier than peripheral cultures in both sets (differential time to positivity approximately 6.2 h and 5.5 h). Echocardiography excluded infective endocarditis. The patient improved following catheter removal and antimicrobial therapy. This case highlights the importance of distinguishing contamination from true bloodstream infection.</p>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":" ","pages":"101321"},"PeriodicalIF":1.5,"publicationDate":"2026-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149223878","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":"The diagnostic gap in hepatitis C confirmation and the predictive value of the anti-HCV signal-to-cutoff ratio: a real-world study.","authors":"Mehmet Ceylan, Cansel Dağdelen, Biray Doğanay, Güneş Şenol","doi":"10.1016/j.ijmmb.2026.101320","DOIUrl":"10.1016/j.ijmmb.2026.101320","url":null,"abstract":"<p><strong>Purpose: </strong>Guidance requires HCV-RNA confirmation for every anti-HCV-reactive individual, yet many are never tested. We quantified this diagnostic gap and examined whether the anti-HCV signal-to-cutoff (S/CO) ratio can help prioritise which untested patients to recall first.</p><p><strong>Methods: </strong>In this retrospective study (STARD 2015) at a tertiary hospital, anti-HCV-positive adults were identified from the laboratory information system. Four immunoassay platforms were used over the record period; because S/CO values are not standardised across assays, the accuracy analysis was restricted to the platform covering most of the cohort, while the diagnostic gap was described for the whole cohort. Performance was assessed by ROC analysis, threshold metrics with 95% confidence intervals (CIs), and logistic regression.</p><p><strong>Results: </strong>Of 773 anti-HCV-positive patients, HCV-RNA was requested in only 354 (45.8%). Untested patients had lower S/CO ratios (median 2.02 vs 3.50; p < 0.001), yet 108 of 419 (25.8%) exceeded 6.5. Ninety-one had died before review; of 268 telephoned, 66 attended and two previously undiagnosed viremic patients began treatment. In the single-platform accuracy set (290 patients, 48 [16.6%] viremic), S/CO ratios were higher in viremic patients (median 13.84 vs 2.46) and predicted viremia with an area under the curve of 0.945 (95% CI 0.919-0.968). The Youden-optimal cut-off was 7.78 (sensitivity 100%, 95% CI 92.6-100; specificity 85.5%). On the preceding platform at the same centre the optimal threshold was 6.50 (area under the curve 0.841).</p><p><strong>Conclusions: </strong>More than half of anti-HCV-positive patients never completed confirmatory testing, and many could no longer be reached. The S/CO ratio discriminated viremia well, but the optimal threshold shifted between successive platforms at a single centre, so no locally derived cut-off can safely govern who is tested. These data support universal reflex HCV-RNA testing on every reactive sample, with the S/CO ratio best used to prioritise the recall of patients already missed.</p>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":" ","pages":"101320"},"PeriodicalIF":1.5,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149193280","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":"Cerebrospinal Fluid Cytokine Signatures in Real-Time PCR-Confirmed Acute Bacterial Meningitis: Diagnostic Insights from TNF-α and IL-1β.","authors":"Shahid Raza, Arti Kapil, Vinay Goyal, Rakesh Lodha, Rama Chaudhry, Deepthi Nair, Seema Sood, Bimal K Das","doi":"10.1016/j.ijmmb.2026.101317","DOIUrl":"https://doi.org/10.1016/j.ijmmb.2026.101317","url":null,"abstract":"<p><strong>Background: </strong>Acute bacterial meningitis (ABM) is a rapidly progressive central nervous system infection where excessive neuroinflammation contributes significantly to morbidity and mortality. Cerebrospinal fluid (CSF) cytokines are key mediators of host immune responses; however, their association with molecular pathogen detection and host inflammatory responses remains incompletely understood OBJECTIVE: To evaluate CSF cytokine responses and their association with molecularly confirmed acute bacterial meningitis METHODS: A total of 246 CSF samples from patients with suspected meningitis, submitted to the department (February 2015 to January 2021) were evaluated. CSF supernatants were used for cytokine quantification, while sediments underwent bacterial culture and Real-time PCR. Cytokines (IL-1β, TNF-α, IL-12p70, IL-6 and IL-10) were measured using cytometric bead array. Receiver Operating Characteristic (ROC) curve analysis evaluated diagnostic accuracy.</p><p><strong>Results: </strong>Bacterial DNA was detected in 53/246 (21.5%) samples, with Streptococcus pneumoniae being the predominant pathogen, particularly in children under five. Real-time PCR-confirmed cases showed significantly higher CSF TNF-α and IL-1β levels compared with non-confirmed cases (p = 0.013 and p = 0.033), indicating a predominant pro-inflammatory cytokine. Elevated IL-10 levels suggested concurrent anti-inflammatory regulation. ROC analysis demonstrated modest overall discrimination for TNF-α (AUC = 0.657, p = 0.013) and IL-1β (AUC = 0.605, p = 0.162). However, at an optimal threshold of 0.60 pg/ml, TNF-α achieved 100% specificity, establishing high reliability.</p><p><strong>Conclusions: </strong>Real-time PCR-confirmed acute bacterial meningitis is characterized by a distinct CSF cytokine signature reflecting coordinated pro-inflammatory activation and regulatory immune responses, highlighting CSF TNF-α as a high-specificity adjunctive to molecular assays.</p>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":" ","pages":"101317"},"PeriodicalIF":1.5,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149193193","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":"Profile and classification of invasive fungal disease in patients with haematologic malignancies using microscopy, culture, biomarkers and polymerase chain reaction.","authors":"Moumita Chakraborty, Malini R Capoor, Sheetal Sharma, Sumita Chaudhary, Rupi Jamwal","doi":"10.1016/j.ijmmb.2026.101319","DOIUrl":"https://doi.org/10.1016/j.ijmmb.2026.101319","url":null,"abstract":"<p><strong>Background: </strong>Invasive fungal diseases (IFDs) are significant causes of morbidity and mortality in patients with haematologic malignancies (HM). This study aimed to classify IFD using integrated diagnostic methods according to European Organization for Research and Treatment of Cancer/Mycoses Study Group Education and Research Consortium (EORTC/MSGERC) criteria.</p><p><strong>Methods: </strong>A prospective observational study was conducted in 100 adult HM patients not on antifungal prophylaxis. Diagnosis included microscopy, culture, galactomannan (GM) enzyme-linked immunosorbent assay (ELISA), Candida mannan immunoglobulin M (IgM) lateral flow assay (LFA), Aspergillus IgM assay, cryptococcal antigen LFA, (1,3)-β-D-glucan (BDG) assay and panfungal polymerase chain reaction (PCR), along with high-resolution computed tomography (HRCT).</p><p><strong>Results: </strong>Probable IFD was observed in 51%, possible in 24%, proven in 12% and no IFD in 13%. Acute leukaemia predominated, with invasive aspergillosis (IA) and candidiasis being the most common infections. Fever was the most frequent presentation, while respiratory symptoms were associated with invasive aspergillosis. PCR showed the highest sensitivity (88.8%), followed by BDG (87.3%). Microscopy and culture were positive in 25% cases, Aspergillus fumigatus being the most common isolate. HRCT was normal in 56%, with ground-glass opacities and consolidation as the most frequent abnormalities.</p><p><strong>Conclusion: </strong>Integrated diagnostic approaches improve classification and early detection of IFD in HM patients and support timely antifungal management.</p>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":" ","pages":"101319"},"PeriodicalIF":1.5,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149181574","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":"Hospital-Based Surveillance of Antimicrobial Resistance in Southern Brazil: Resistance Profiles and Phenotypic Carbapenemase Screening.","authors":"Matheus Sebastian da Silva, Tesie Fonseca, Ana Julia Reis, Daniela Ramos, Hélio Henrique da Silva Abreu, Ivy Ramis, Andrea Von Groll, Pedro Eduardo Almeida da Silva","doi":"10.1016/j.ijmmb.2026.101309","DOIUrl":"https://doi.org/10.1016/j.ijmmb.2026.101309","url":null,"abstract":"<p><strong>Purpose: </strong>To describe the distribution of clinically relevant bacterial pathogens and their antimicrobial resistance profiles in a tertiary university hospital in southern Brazil, with emphasis on carbapenem resistance and phenotypic carbapenemase screening.</p><p><strong>Methods: </strong>This retrospective study analysed 1,513 clinical isolates recovered during 2024 after exclusion of 1,304 surveillance or colonisation records. Identification and antimicrobial susceptibility testing were performed using the BD Phoenix M50 system and interpreted according to BrCAST/EUCAST criteria. Carbapenem-resistant Gram-negative isolates were screened phenotypically for carbapenemase activity using the Blue-Carba assay.</p><p><strong>Results: </strong>Among the clinical isolates, 1,397 were processed through the university hospital and 116 originated from external municipal healthcare services. Hospital-acquired, community-acquired, and non-classified infections accounted for 58.2%, 32.9%, and 8.9%, respectively. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequent Gram-negative pathogens. Meropenem resistance was 75.7% (28/37) among Acinetobacter baumannii and 37.8% (42/111) among P. aeruginosa. Oxacillin resistance was detected in 40.3% (27/67) of S. aureus isolates.</p><p><strong>Conclusion: </strong>Carbapenem resistance was particularly concerning among non-fermenting Gram-negative bacteria, especially A. baumannii and P. aeruginosa. The findings support stronger antimicrobial stewardship, infection-prevention measures, and laboratory-based surveillance. Molecular studies are required to define the underlying resistance determinants and investigate possible clonal dissemination.</p>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":" ","pages":"101309"},"PeriodicalIF":1.5,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149108903","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":"Aims and Scope","authors":"","doi":"10.1016/S0255-0857(26)00214-8","DOIUrl":"10.1016/S0255-0857(26)00214-8","url":null,"abstract":"","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":"63 ","pages":"Article 101255"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Environmental source of histoplasmosis in India: An unsolved One Health enigma","authors":"Awantika Jha,&nbsp;Sonakshi Srivastava,&nbsp;Pryanka Thakur,&nbsp;Ranjit Das,&nbsp;Sayantan Banerjee","doi":"10.1016/j.ijmmb.2026.101162","DOIUrl":"10.1016/j.ijmmb.2026.101162","url":null,"abstract":"<div><h3>Background</h3><div>Histoplasmosis is an emerging mycosis in India. Although clinical cases are increasingly recognized, the environmental niche of the <em>Histoplasma</em> (<em>H</em>.) <em>capsulatum</em> fungus remains poorly defined, with only a single soil isolation reported from India in 1975.</div></div><div><h3>Objective</h3><div>To investigate the presence of <em>H</em>. <em>capsulatum</em> in soil samples from endemic regions of West Bengal using conventional culture and sensitive molecular methods.</div></div><div><h3>Method</h3><div>Forty-five soil samples were collected from Nadia and Bardhaman districts, targeting sites enriched with high nitrogen content, such as areas under the trees, uprooted soil, and abandoned houses. The soil samples were cultured on Sabouraud's dextrose agar with antibiotics and incubated for four weeks. DNA extracted from soil suspensions using a commercial kit was analyzed by TaqMan-based real-time PCR targeting the internal transcribed spacer region of <em>H. capsulatum</em>.</div></div><div><h3>Results</h3><div>None of the samples were positive for <em>H. capsulatum</em> using conventional culture and/or RT-PCR. Nevertheless, the samples were positive for other saprophytic fungi, including <em>Penicillium, Zygomycetes,</em> and <em>Acremonium spp</em>. Real-time PCR demonstrated high sensitivity (10 fg of <em>H. capsulatum</em> DNA/μl). However, no amplification was observed in any of the soil samples, indicating no detectable presence of <em>H. capsulatum</em> DNA in the sampled locations in India.</div></div><div><h3>Conclusion</h3><div>The absence of <em>H. capsulatum</em> detection may reflect limited sample size, sampling bias, or patchy distribution of the fungus, suggesting the need for large-scale surveys combined with sensitive molecular methods. Therefore, strengthening environmental surveillance within a One Health framework will be crucial for better understanding and control of histoplasmosis in endemic regions.</div></div>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":"62 ","pages":"Article 101162"},"PeriodicalIF":1.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148162826","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":"Interpreting ceftazidime-avibactam plus aztreonam synergy testing in the era of aztreonam-avibactam","authors":"Rahul Garg,&nbsp;Tuhina Banerjee","doi":"10.1016/j.ijmmb.2026.101170","DOIUrl":"10.1016/j.ijmmb.2026.101170","url":null,"abstract":"","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":"62 ","pages":"Article 101170"},"PeriodicalIF":1.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148251424","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":"Diagnostic utility of 16S rRNA meta genomic next-generation sequencing in clinical infectious diseases practice: a retrospective study from South India","authors":"Pugazhvanan CR,&nbsp;Vidya Krishna,&nbsp;Nandini Sethuraman,&nbsp;Senthur Nambi P,&nbsp;Venkatasubramanian Ramasubramanian,&nbsp;Praveen Balaguru,&nbsp;Ram Gopalakrishnan","doi":"10.1016/j.ijmmb.2026.101166","DOIUrl":"10.1016/j.ijmmb.2026.101166","url":null,"abstract":"<div><h3>Objectives</h3><div>16S rRNA sequencing is an emerging diagnostic tool for bacterial syndromes caused by fastidious pathogens and in culture negative infections. However, it can pose significant challenges from pre-analytic to post-analytic phase due to sampling issues, lack of an approved platform and test characteristics. We aimed to evaluate the diagnostic performance of 16S rRNA sequencing in sterile site samples compared to conventional microbiological techniques [CMT] and a composite reference standard [CRS].</div></div><div><h3>Methods</h3><div>We conducted a retrospective study at a tertiary hospital from January 2022 to July 2024. We included clinical data of patients with sterile site samples processed for both CMT and 16S rRNA sequencing. Sequencing used the Credence Genomics pipeline.</div></div><div><h3>Results</h3><div>166 samples met the inclusion criteria: 97 tissue, 35 pus, and 34 fluid samples. Pathogen detection rate was 42.8% [71/166] by CMT and 58.4% [97/166] by 16S rRNA. Concordance between methods was 50.6%. Sensitivity and specificity of 16S rRNA against CMT was 60.6% and 43.2%; and 69.4% and 66.7% against CRS respectively. CMT showed 54% sensitivity and 92.9% specificity against CRS. Combined testing improved sensitivity to 84.7% and accuracy was 78.9%.</div></div><div><h3>Conclusion</h3><div>16S rRNA sequencing provides incremental diagnostic sensitivity over conventional microbiological techniques but at the cost of reduced specificity. Its routine frontline use as a standalone diagnostic tool is not supported by our findings. Instead, it may be best reserved for selected culture-negative cases with high clinical suspicion, where results can be interpreted in conjunction with clinical, radiological, and microbiological data by experienced clinicians.</div></div>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":"62 ","pages":"Article 101166"},"PeriodicalIF":1.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148257866","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":"Phenotypic drug susceptibility testing and genotypic characterization of Bedaquiline resistance in drug resistant Mycobacterium tuberculosis","authors":"Annie Sheeba Victor,&nbsp;Manigandan V,&nbsp;Marilyn Mary Ninan,&nbsp;Richa Gupta,&nbsp;Asha Frederick,&nbsp;Ranjani Ramachandran,&nbsp;Grace Rebekah,&nbsp;Joy Sarojini Michael","doi":"10.1016/j.ijmmb.2026.101163","DOIUrl":"10.1016/j.ijmmb.2026.101163","url":null,"abstract":"<div><h3>Purpose</h3><div>The new drugs bedaquiline, delamanid, and pretomanid have been approved for treating drug-resistant tuberculosis. The World Health Organization currently recommends the BPaL(M) regimen, which lasts 6-9 months, for managing drug-resistant tuberculosis. This study aimed to perform phenotypic drug susceptibility testing and identify mutations linked to bedaquiline resistance through whole genome sequencing.</div></div><div><h3>Methods</h3><div>We conducted a prospective cohort study involving 297 drug-resistant <em>Mycobacterium tuberculosis</em> isolates from patients visiting the respiratory medicine outpatient department at Christian Medical College, Vellore, and district TB centers across six districts in Tamil Nadu over the course of five years (2019-2023). These isolates underwent phenotypic drug susceptibility testing for bedaquiline using the BACTEC™ MGIT™ 960 system, following WHO guidelines. WGS was performed on a subset of 150 isolates using the Illumina platform, followed by mutation analysis using BLASTIN.</div></div><div><h3>Results</h3><div>The study found a 7% prevalence of bedaquiline resistance. A total of 39 variants were identified across four candidate genes associated with BDQ resistance: <em>Rv0678</em>, <em>mmpL5</em> (<em>Rv0676c), pepQ,</em> and <em>Rv1979c</em>. No variants were observed in the <em>Rv0677c, Rv1304,</em> or <em>atpE</em> genes in any of the tested isolates. All isolates (100%) had at least one variant in the <em>Rv0676c</em> gene.</div></div><div><h3>Conclusion</h3><div>This study identified the most common genetic variants linked to BDQ resistance from a tertiary care center in India. Larger studies across the country are necessary to explore the phenotypic and genotypic resistance profiles of BDQ and other drugs used in all-oral shorter regimens being introduced in India for the treatment of multidrug-resistant TB.</div></div>","PeriodicalId":13284,"journal":{"name":"Indian Journal of Medical Microbiology","volume":"62 ","pages":"Article 101163"},"PeriodicalIF":1.5,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148224823","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}