Journal of Clinical Microbiology最新文献

The resurgence of monkeypox virus (MPXV) has increased demand for validated serological assays to assess exposure and immunity. Cross-reactivity among orthopoxviruses, stemming from high sequence conservation, complicates distinguishing antibody responses from natural MPXV infection versus vaccination or other orthopoxvirus exposures. We validated the Meso Scale Discovery (MSD) V-PLEX Orthopoxvirus Panel 1 (IgG) Kit, which quantifies antibody levels to five MPXV antigens and their vaccinia virus (VACV) orthologs, following Good Clinical Laboratory Practice guidelines. We assessed assay performance using serum from 26 individuals with prior mpox, 52 JYNNEOS vaccine recipients, and 179 unexposed controls. The assay reliably detected antibody responses in all exposed cohorts with peak levels observed 2 months post-vaccination. Antibody levels to specific antigens also correlated with Modified Vaccinia Ankara neutralization titer, particularly for MPXV B6R/VACV B5R, MPXV E8L/VACV D8L, and MPXV M1R/VACV L1. Receiver operating characteristic analysis showed that some individual antigens achieved high sensitivity and specificity for exposure detection (area under the curve [AUC] > 0.96 for VACV D8L, MPXV B6R, VACV B5R); however, individual antigens performed poorly in distinguishing infection from vaccination. In contrast, antibody level ratios between some MPXV and VACV orthologs effectively differentiated MPXV infection from vaccinia vaccination with high sensitivity and specificity (e.g., MPXV A35R/VACV A33R ortholog ratio, AUC = 0.97, sensitivity = 0.97, specificity = 0.96). Our findings validate the MSD assay for clinical research and serosurveillance to assess MPXV immunity and support the utility of ortholog pair ratio analysis as a strategy to discriminate vaccinated and infected individuals.

Importance: Mpox continues to spread around the world, with recent data showing increasing incidence in the United States. While there are multiple Food and Drug Administration (FDA)-authorized real-time PCR tests for diagnostic use, there are no FDA-authorized serological tests and few laboratory-developed serological tests offered. We evaluated the Meso Scale Discovery V-PLEX Orthopoxvirus Panel 1 (IgG) Kit according to Good Clinical Laboratory Practice guidelines and found that the assay reliably detected antibody responses in monkeypox virus (MPXV)- and vaccinia virus (VACV)-exposed cohorts and could distinguish them from unexposed cohorts. Intriguingly, we found that antibody level ratios between certain MPXV and VACV orthologs could distinguish prior mpox infection from vaccinia vaccination. Overall, these data highlight the use of multi-antigen panels in challenging scenarios for serological testing, such as the cross-reactivity presented by orthopoxviruses.

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.

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.

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.