Invasive fungal disease (IFD) is a major cause of morbidity and mortality in the immunocompromised population. Early diagnosis is challenging due to the low sensitivity and non-specificity of non-invasive fungal biomarkers, the need for invasive specimen collection, and the limitations of culture and histopathology. Detection of circulating fungal cell-free DNA (cfDNA) in plasma and serum by polymerase chain reaction (PCR) represents a novel testing modality for rapid and accurate diagnosis of IFD. In this review, we summarize the performance characteristics of fungal cfDNA PCR for the diagnosis of invasive aspergillosis, mucormycosis, and Pneumocystis pneumonia. We discuss a testing algorithm that incorporates fungal cfDNA and the added diagnostic value of invasive specimen collection when non-invasive mold cfDNA PCR is performed first. Lastly, we discuss the role of diagnostic stewardship in fungal cfDNA PCR testing.
Blood culture contamination is common, causing diagnostic uncertainty and unnecessary antibiotic use. Analyzing growth patterns within culture sets might offer diagnostic value. We retrospectively analyzed peripheral blood culture sets from 2019 and 2024. Growth pattern (one bottle [discordant] vs both bottles [concordant]) was analyzed according to clinical significance (contaminant vs true pathogen). Overall, 38,216 blood culture sets were analyzed, including 1,491 (3.9%) discordant and 1,938 (5.1%) concordant sets (remaining 34,787 [91.0%] sets were sterile). Discordant sets grew 1,060/1,491 (71.1%) contaminants and 431/1,491 (28.9%) true pathogens. Concordant sets grew 222/1,938 (11.4%) contaminants and 1,716/1,938 (88.5%) true pathogens (P < 0.001). Examining coagulase-negative staphylococci (CoNS) only (2019 data set), 629/642 (98.0%) discordant sets grew contaminants, while 13/642 (2.0%) grew true pathogens. In contrast, Staphylococcus aureus grew in only 82/270 (30.4%) discordant sets. Among 858 first CoNS-positive cultures per patient, 624/636 (98.1%) discordant sets grew contaminants, and 12/636 (1.9%) grew CoNS defined as a true pathogen. The negative predictive value of a discordant first CoNS set to exclude true CoNS bacteremia was 98.1% (95% confidence interval 96.7%-98.9%). Examining aerobic vs anaerobic bottles in 356 discordant sets, contaminants were found more frequently in aerobic bottles (135/356, 37.9% vs 73/356, 20.5%, P = 0.04). The proportion of true pathogens was similar in both (79/356, 22.2% vs 69/356, 19.4%, P = 0.4). Discordant CoNS-positive cultures were strongly associated with contamination. This could assist in interpreting blood culture results and supporting antimicrobial stewardship. Discordance might result from a diversion effect, the aerobic bottle acting as a diversion device for the anaerobic bottle.IMPORTANCERapidly distinguishing blood culture contaminants from true pathogens is essential for optimizing antimicrobial stewardship and avoiding unnecessary antibiotic therapy. In this large, two-period study, we demonstrate that discordant growth of coagulase-negative staphylococci in a two-bottle set has a negative predictive value of 98.1% for true bacteremia. This finding remained robust across both study years and when restricted to first positive cultures, highlighting its reliability. Incorporating simple growth pattern analysis into early blood culture interpretation can provide clinicians with reliable and timely information within 24 hours, supporting more targeted and judicious antibiotic use.
Hepatitis B virus (HBV) DNA testing is essential for the management of HBV infection. Routine HBV DNA tests in central laboratories are expensive and require processed venous blood, limiting accessibility. This study is the first published assessment of the point-of-care Xpert HBV DNA assay performance using fingerstick capillary blood compared with standard-of-care venous blood testing. Participants with chronic HBV infection were enrolled from six hospitals. Fingerstick capillary blood was tested using Xpert HBV Viral Load assay (quantification lower limit: 100 IU/mL). Venipuncture whole blood was tested with COBAS AmpliPrep/COBAS TaqMan HBV DNA Test (gold standard). The sensitivity and specificity of the Xpert were evaluated for identifying HBV DNA ≥100 and >2,000 IU/mL. Agreement between quantitative measurements of assays was assessed. A total of 246 participants were included (median age 45, 46% female, 18% HBeAg positive, 48% on HBV treatment, 6% with cirrhosis). For HBV DNA ≥100 IU/mL, the sensitivity and specificity of the Xpert were 97.0% (95% CI: 94.9, 99.1) and 90.3% (86.6, 94.0), respectively. For HBV DNA >2,000 IU/mL, the sensitivity and specificity were 95.3% (92.7, 98.0) and 95.0% (92.4, 97.8), respectively. Viral load differences in non-concordant samples ranged from 0.1 to 1.1 log IU/mL. Overall, the Xpert viral loads were a mean 0.12 log IU/mL higher than gold standard (95%CI: -0.43, 0.67). In conclusion, minimal differences in HBV DNA levels were identified between the Xpert and gold standard assays, with differences in non-concordant results unlikely to impact clinical decisions. This evidence supports developing a dedicated Xpert HBV DNA fingerstick assay for decentralized care, crucial for remote, resource-limited settings and hard-to-reach populations, including prenatal care for women with HBV.IMPORTANCEThis study represents the first assessment of a point-of-care hepatitis B virus (HBV) DNA assay using fingerstick capillary blood (Xpert HBV Viral Load assay). Our findings demonstrated high sensitivity and specificity for the point-of-care test, with close agreement between the point-of-care and standard-of-care assays across the full quantitative spectrum of HBV viral load measurements. Importantly, the differences between the assays in participants with non-concordant results were not substantial enough to alter clinical management, suggesting that this point-of-care method is both accurate and reliable for clinical use. By highlighting the potential for decentralizing HBV care, our research provides compelling evidence to support the development of a dedicated Xpert HBV DNA point-of-care test. Such a development could greatly benefit patients in remote and resource-limited settings, where access to laboratory-based testing is limited.
The article by S. J. Oyeniran, A. L. Leber and H. Wang (J Clin Microbiol 63:e00986-25, 2025, https://doi.org/10.1128/jcm.00986-25) describes a novel laboratory-developed diagnostic PCR assay that amplifies the gene encoding Kingella kingae's major outer membrane protein. The test confirmed the prime role of the organism causing skeletal system infections in preschoolers and enabled the administration of targeted antibiotic therapy. It is hoped that a much-needed commercial K. kingae-specific molecular test will soon receive FDA clearance to improve the management of pediatric osteoarticular infections.
Rapid TB diagnostics are essential for effective TB control. Combining WHO-recommended rapid molecular tests with downstream targeted next-generation sequencing (tNGS) enables faster drug resistance profiling. The objective of this study was to establish a one-day diagnostic platform (ODDP) integrating BD MAX MDR-TB and AmPORE-TB tNGS from a single sample. Pooled sputum samples spiked with 52 pre-characterized Mycobacterium tuberculosis (MTB) strains and 74 MTB-positive clinical samples were tested using BD MAX MDR-TB for TB, isoniazid, and rifampicin resistance. tNGS was performed from 5 µL of purified DNA leftover for each TB-positive sample in the BD MAX strips. IS6110/IS1081 Ct-values served as surrogate markers for TB DNA concentration. A total of 104 spiked and 60 clinical samples tested positive by BD MAX. The average time to the final ODDP result was 8.5 h. For samples with Ct ≤28, tNGS generated antibiotic resistance profiles for ≥12 antibiotics with 85.1% sensitivity in spiked and 73% in clinical samples. Failure rates were 10% and 8.3%, respectively. Resistance profiling most frequently (up to 11.3%) failed for clofazimine, pretomanid, and delamanid. The ODDP enables comprehensive TB diagnosis and resistance profiling from a single sample in 1 day. This platform can significantly accelerate the time to informed drug-resistant (DR)-TB treatment decisions.IMPORTANCEReducing the time to treatment initiation decreases patient drop-out rates, morbidity, the emergence of new drug resistances, and onward transmission of infection. Obtaining the complete resistome from the start is crucial for choosing a fully effective treatment regimen. Until now, diagnosis with full resistance profiling has required at least two sputum samples and 3 to 7 days for the complete workflow, obliging patients to return two to three times, which dramatically increased the risk of loss to follow-up. Our one-day diagnostic platform enables both diagnosis and comprehensive resistance testing from a single sample within 1 day. Patients can remain in a day clinic during testing and receive a fully effective, individualized treatment regimen the same day. This approach is expected to markedly reduce morbidity, drop-out rates, and transmission. The necessary instruments and technologies are already available in many high-prevalence countries and are currently being rapidly scaled up worldwide.
Burkholderia cepacia complex (BCC) is a highly antimicrobial-resistant bacteria that frequently colonizes patients with cystic fibrosis. Previous studies have demonstrated inconsistent performance and questionable reliability of disk diffusion, agar dilution, gradient diffusion strip, and Microscan methods. This study evaluated the performance of the Biomerieux Vitek 2, Thermo Scientific Sensititre broth microdilution, and Etest methods for susceptibility testing of BCC organisms in comparison to a previously characterized isolate set. Of the three methods tested, Sensititre had the highest Essential and Categorical agreements (EA and CA, respectively) , though it still produced multiple Very Major Errors (VME). Vitek 2 had the lowest EA and CA, especially for ceftazidime and meropenem. For all three methods, there was a trend of lower minimum inhibitory concentrations and increased Susceptible results in comparison to the reference broth microdilution method, resulting in a high number of VME. While none of the methods met acceptance criteria, Sensititre may offer the best commercially available option for clinical laboratories in circumstances where antimicrobial susceptibility testing is warranted.IMPORTANCEAntimicrobial susceptibility testing (AST) of Burkholderia cepacia complex isolates remains of interest due to their inherent multidrug resistance. Previous studies have demonstrated unreliable performance of various methods. As clinical laboratories seek options to perform testing in cases where AST is needed, this study provides data on the performance of three commercially available methods: the Biomerieux Vitek 2, Thermo Scientific Sensititre panels, and the Biomerieux Etest.
HIV serologic responses measured by clinical screening assays may be blunted when antiretroviral treatment (ART) suppresses HIV replication from the initial infection stages, with further decay following long-term treatment. Sensitivity may vary according to the timing of ART initiation after HIV acquisition, antigens (Ags) utilized to detect anti-HIV antibodies (Abs), and HIV subtype. We obtained samples from long-term ART-suppressed persons with HIV (PWH) who started ART at acute/early or during chronic infection, from blood donors with undetectable HIV RNA and nonreactive serology, and from blood donors with positive RNA and reactive serology (presumably untreated infections) spanning multiple HIV subtypes to compare patterns of serologic reactivity using two Ag/Ab screening assays (Alinity and VITROS). We found that earlier ART initiation was associated with progressively lower signal-to-cutoff ratios (S/CO) in both assays. Serologic reactivity in clinical samples from participants initiating ART at Fiebig 2 was somewhat lower for CRF01_AE (67%) than other HIV subtypes (91%) on the Alinity platform. In the late-ART initiation group, reactivity was high for both assays despite long-term treatment, with higher S/CO values in samples from blood donors with presumably untreated infection. We observed no strong evidence of S/CO waning >96 weeks after ART initiation in the early-ART initiation group. Our findings suggest potential limitations for HIV infection ascertainment in clinical samples from long-term treated PWH who started ART at early infection stages using currently approved serologic tests.IMPORTANCEThis manuscript increases our understanding of how the timing of initiation of HIV treatment affects our ability to detect the infection using commercial blood tests that measure HIV antigens or antibodies. Being able to detect HIV is important for clinical diagnostics and blood screening, and HIV is not as easily detected in persons who begin therapy shortly after infection using serological tests. In contrast to prior work, we show that current clinical HIV tests have stable reactivity over time in persons on long-term HIV treatment.
Recognizing and updating bacterial names is key to communication between the veterinary clinical microbiology laboratory, veterinarians, and clients. Moraxella oculi sp. nov., distinct from Moraxella bovis and Moraxella bovoculi, was isolated from a cow with infectious bovine keratoconjunctivitis. Several respiratory pathogens were recognized, including Neisseria leonii sp. nov. described from rabbits, Mannheimia indoligenes sp. nov. described from cattle in Europe, and Moraxella haemolytica sp. nov. described from a goat in China. Stenotrophomonas forensis sp. nov. is a novel designation within the Stenotrophomonas maltophilia complex associated with isolates derived from horses. New additions to the Campylobacter genus included Campylobacter californiensis sp. nov., recovered from bovine feces during a raw milk-associated outbreak of campylobacteriosis in humans. Taxonomic revisions were most notable in Gram-positive organisms. A species within genus Jeotgalicoccus has been renamed, and the subspecies designation Kocuria rosea subsp. polaris comb. nov. has been created. Streptococcus suis was revised to Streptococcus suis subsp. suis subsp. nov. in recognition of the initial description of Streptococcus suis subsp. hashimotonensis subsp. nov., which was isolated from people in Japan with bite wounds from boars. Chlamydophila caviae, which causes respiratory disease and abortion in guinea pigs and is zoonotic, has been revised to Chlamydia caviae comb. nov.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：