Recovery of multiple microorganisms from respiratory specimens complicates pathogen attribution in patients with chronic lung disease. A 71-year-old woman with COPD and bronchiectasis presented with severe pneumonia and respiratory failure. She had T-cell lymphopenia (CD3+, CD4+, and CD8+ counts: 189, 147, and 41 cells/μL) and negative HIV testing. BALF Gram staining showed branching Gram-positive rods suspicious for Nocardia spp., and cultures yielded a Nocardia isolate, Aspergillus fumigatus, and Candida albicans. The isolate was presumptively identified as N. terpenica by MALDI-TOF MS (score, 9.534); molecular confirmation and susceptibility testing were unavailable. BALF galactomannan (index, 3.528) supported probable pulmonary aspergillosis. Influenza A virus RNA was detected by qualitative PCR, while C. albicans was considered airway colonization. The patient improved during hospitalization. This case highlights integrated pathogen attribution in complex respiratory microbiology.

Distinguishing between histoplasmosis and sarcoidosis can be challenging as both can present with non-specific clinical findings. We present a 73-year-old immunocompetent Caucasian male who was recently diagnosed with sarcoidosis via left upper lobe biopsy who presented with lethargy and poor oral intake. The patient was found to have fever, splenomegaly, pancytopenia, hypofibrinogenemia, and elevated inflammatory markers. After bone marrow biopsy, he was diagnosed with disseminated histoplasmosis and secondary hemophagocytic lymphohistiocytosis (HLH). The patient was treated with liposomal amphotericin B and a dexamethasone taper followed by itraconazole for 1 year. After the patient was found to have disseminated histoplasmosis, his original diagnosis of sarcoidosis was reconsidered. Disseminated histoplasmosis is a rare cause of secondary HLH in an immunocompetent adult. This case highlights the difficulties distinguishing between histoplasmosis and other causes of granulomatous disease and identifies histoplasmosis as a rare cause of HLH.

Lipoarabinomannan (LAM), recognized as a characteristic antigen within the cell wall of Mycobacterium tuberculosis (MTB), can be detected in the urine of patients suffering from active tuberculosis, which provides an important biomarker for non-invasive diagnosis of tuberculosis. This paper systematically reviews the structure, immunomodulatory function and application value of LAM in the diagnosis of tuberculosis, focusing on the progress and performance comparison of various detection methods from traditional ELISA to emerging quantum dot microsphere technology. Studies have indicated that LAM test has high sensitivity and specificity in HIV-positive patients, especially in CD4 low patients, but the diagnostic efficiency in HIV-negative people still needs to be improved. Nanotechnology such as quantum dots has significantly improved the detection sensitivity (up to fg/mL) through signal amplification and multimodal output, and has shown good potential for point-of-care application. In the future, the development of LAM detection technology should focus on platform integration and intelligence, joint detection of multiple markers, population stratification optimization and standardization system construction. Together, these efforts will make it an important diagnostic tool in the global TB system.

Blastocystis is a ubiquitous intestinal microeukaryote with controversial pathogenic potential. Epidemiological data on Blastocystis in patients with gastrointestinal neoplasms remain limited, especially in tropical regions of China. This study aimed to determine the prevalence and molecular subtype distribution of Blastocystis in hospitalized patients with gastrointestinal cancer or polyps in Hainan Province. A descriptive cross-sectional study was conducted at a tertiary hospital in Hainan. A total of 509 consecutive patients were enrolled, including 357 with pathologically confirmed gastrointestinal cancer and 152 with gastrointestinal polyps. Blastocystis was detected by nested PCR targeting the SSU rRNA gene, and positive amplicons were sequenced for subtype identification. The overall detection rate of Blastocystis was 2.2% (11/509) in gastrointestinal tumor patients, with 1.7% (6/357) and 3.3% (5/152) in gastrointestinal cancer and polyp patients, respectively. Three subtypes (STs) were identified: ST3 (n = 7, 63.6%), ST1 (n = 2, 18.2%), and ST7 (n = 2, 18.2%). ST1 and ST3 are known to circulate widely in human populations, while ST7 is primarily an avian-adapted subtype with occasional zoonotic potential. An exploratory analysis suggested a possible age-dependent colonization pattern in polyp patients (uncorrected P = 0.003), but this finding requires validation in larger cohorts due to the small sample size. This study provides baseline data on Blastocystis subtype distribution in gastrointestinal disease patients in Hainan. Further well-designed studies with appropriate control groups and rigorous control for confounding factors are required to clarify the clinical significance of Blastocystis colonization in this patient population.

Accurate species-level identification within the genus Serratia remains challenging due to extensive phenotypic overlap and high genomic relatedness among closely related and recently described taxa. This study presents an evaluation of routine and genome-based identification approaches applied to clinical Serratia isolates, integrating phenotypic assays, MALDI-TOF MS (Bruker Daltonics), 16S rRNA gene sequencing, and Whole-Genome Sequencing (WGS). A total of 103 isolates collected from a teaching hospital were analyzed. WGS was performed on a subset of isolates. Conventional biochemical methods classified all isolates as Serratia marcescens, whereas MALDI-TOF MS identified 60.1% as S. marcescens, 11.6% as S. ureilytica, and 28.1% just at the genus level. Peak analysis from MALDI-TOF MS revealed specific peaks associated with S. marcescens and S. ureilytica, but limited discriminatory power. WGS of six isolates initially identified as S. ureilytica by MALDI-TOF MS revealed reclassification as Serratia sarumanii (n = 5) and Serratia montpellierensis (n = 1), supported by Average Nucleotide Identity (ANI), Average Amino Acid Identity (AAI), and Digital DNA-DNA Hybridization (dDDH) thresholds. In contrast, 16S rRNA analysis showed limited species-level resolution. Phylogenomic and SNP-based analyses confirmed these classifications with strong support. Overall, this study underscores the critical role of high-resolution genomic approaches for precise species identification and highlights the need for continuous expansion and curation of MALDI-TOF MS reference databases to support reliable clinical diagnostics and epidemiological surveillance of emerging Serratia species.

Bloodstream infections (BSIs) due to Gram-negative bacteria can rapidly escalate to life-threatening conditions, making the early selection of the appropriate antibiotics crucial for saving lives. Current conventional laboratory antimicrobial susceptibility tests for identifying effective antibiotics typically require 16-24 hours in addition to the sub-culture time, prolonging time-to-result (TTR) and delaying appropriate therapy. In this study, we compared the fast antimicrobial susceptibility test (AST) system VITEK® REVEAL[TM] (VITEK REVEAL) with BD Phoenix[TM] (BD Phoenix) on 192 prospectively collected blood cultures positive for Gram-negative organisms (n = 184 after exclusions) from two U.S. study sites. A total of 12 Gram-negative species were evaluated against a panel of 20 antimicrobials. Performance was assessed by essential agreement (EA), categorical agreement (CA), and rates of very major (VMD), major (MD), and minor discrepancies (miD). BD Phoenix served as the reference comparator, whereas broth microdilution (BMD) was applied for isolates with VMD or MD discordant results between the two systems. TTRs were recorded for both systems. VITEK REVEAL achieved EA 98.74% (95% CI: 98.26-99.12%) and CA 97.58% (95% CI: 96.95-98.11%) in 2,854 microorganism-antimicrobial combinations. Rates of discrepancies between the systems were 4.24% for VMD, 0.23% for MD and 1.96% for miD. Median instrument TTR was 8.0 hours for VITEK REVEAL versus 13.8 hours for BD Phoenix (p < 0.001), noting that BD Phoenix TTR values did not include the required 18-24 hours pre-AST subculture time. On the VITEK REVEAL, resistant isolates were reported earlier than susceptible ones (5.0 h vs 6.5 h; p < 0.001). Overall, VITEK REVEAL showed high concordance with BD Phoenix and demonstrated faster TTR, which can potentially facilitate Gram-negative BSI therapy optimization.