Microbiology spectrum最新文献

Saxifraga stolonifera Meeb is widely used as a traditional Chinese medicine for the treatment of infections. This study aims to evaluate the antibacterial properties and suppression of virulence by Saxifraga stolonifera Meeb extracts on Pseudomonas aeruginosa. Following extraction of Saxifraga stolonifera Meeb with petroleum ether, ethyl acetate, n-butyl alcohol, and water, the n-butyl alcohol extract had the strongest activity against P. aeruginosa PAO1 and P. aeruginosa ATCC27853, with minimum inhibitory concentration (MIC) values of 10 and 5 mg/mL, respectively. In the presence of the n-butyl alcohol (n-BuOH) extract at 1/4MIC, genes lasI, lasR, rhlI, phzA1, phzA2, and pilG were decreased to levels ranging from 13% (lasI) to 43% (phzA2). Both biofilm formation and pyocyanin production of PAO1 were inhibited by the n-BuOH extract at sub-inhibitory concentrations. N-butyl alcohol extract analyzed by HPLC-Q-TOF-MS/MS showed more than 11 compounds. Overall, our results suggest that the n-BuOH extract from Saxifraga stolonifera Meeb may be used as a new anti-virulence agent for P. aeruginosa infection.

Importance: Pseudomonas aeruginosa infections pose severe challenges to clinical treatment, and anti-virulence therapy has emerged as a novel therapeutic strategy. This study demonstrates that the n-butanol extract of Saxifraga stolonifera exerts anti-virulence effects by downregulating virulence-related genes, inhibiting quorum-sensing systems, and biofilm formation. Moreover, its multiple bioactive components also possess antibacterial and anti-virulence properties. S. stolonifera is thus promising to be developed into a novel anti-virulence inhibitor against P. aeruginosa for the prevention and treatment of clinically relevant infections.

Marek's disease, a highly contagious avian immunosuppressive disorder caused by the α-herpesvirus MDV-1, poses a significant threat to poultry health. The development of rapid visual detection methods capable of distinguishing epidemic MDV-1 strains from vaccine strains is crucial for early disease warning, vaccine efficacy evaluation, and precise disease control. We developed a novel isothermal detection system that integrates recombinase polymerase amplification (RPA) with CRISPR/Cas14a technology for the visual identification of epidemic MDV-1 strains. This method operates at a constant temperature of 37°C and allows for either real-time analysis or endpoint visual readout without the need for complex instrumentation. Our results showed no cross-reactivity with Newcastle disease virus, infectious bursal disease virus, MDV-1 vaccine strains, or herpesvirus of turkeys. Plasmid DNA standards were used to determine the sensitivity of the assay, and the detection limit was 24.6 copies/μL. Clinical evaluation using 24 field samples confirmed that the method successfully identified all Marek's disease virus-positive cases, demonstrating its diagnostic reliability. In conclusion, we have developed a rapid, highly specific nucleic acid detection platform for MDV-1 that enables visual readout without complex instrumentation by combining the sensitivity of RPA with the specificity of CRISPR/Cas14a technology, offering promising potential for field-based diagnostics and disease surveillance.IMPORTANCEMarek's disease virus (MDV-1) is a highly contagious and economically important avian pathogen. Existing diagnostic methods are unable to reliably distinguish between epidemic and vaccine strains in field settings, which hampers effective surveillance and evaluation of vaccination programs. To address this challenge, we developed a portable isothermal detection assay that combines recombinase polymerase amplification with CRISPR/Cas14a technology. This approach enables highly sensitive (24.6 copies/μL) and specific visual detection of epidemic MDV-1 strains without cross-reactivity with vaccine strains or related viruses. The assay demonstrated 100% agreement with reference methods when evaluated using clinical samples. As a cost-effective method that avoids the need for complex detection instruments, it offers a practical solution for rapid on-site diagnosis, facilitating enhanced outbreak control and improved poultry health management globally.

To evaluate the performance of the iFIND INH/FQ, a low-complexity molecular assay, for the rapid and simultaneous detection of resistance to isoniazid (INH) and fluoroquinolones (FQs) in Mycobacterium tuberculosis. Frozen sputum specimens stored at the Chengde Center for Disease Control and Prevention laboratory were used. Phenotypic drug susceptibility testing (pDST) and DNA sequencing served as reference standards. The limit of detection (LOD) was determined using probit regression with spiked samples. The assay's ability to detect resistance-conferring mutations in katG, inhA, and gyrA genes was assessed using genotypically characterized strains. Diagnostic accuracy was evaluated against pDST. The LOD was 20.79 CFU/mL for INH and 9.34 CFU/mL for FQs. The assay detected all targeted mutations except ahpC c.-6 associated with INH resistance. Compared to pDST, the iFIND INH/FQ assay demonstrated a sensitivity of 97.59% (95% confidence interval [CI]: 91.63-99.34%) and specificity of 98.10% (95% CI: 94.57-99.35%) for INH resistance. For FQ resistance, sensitivity was 92.16% (95% CI: 81.50-96.91%) for levofloxacin and 92.00% (95% CI: 81.16-96.85%) for moxifloxacin, with specificities of 97.33% (95% CI: 93.89-98.85%) and 96.81% (95% CI: 93.21-98.53%), respectively. Sequencing confirmed iFIND results in the majority of discrepant cases (100% for INH and 55.65% for FQs). The iFIND INH/FQ LC-aNAAT is a highly accurate and rapid molecular assay for simultaneous detection of INH and FQ resistance. It is a promising tool for scaling up rapid drug susceptibility testing in clinical and peripheral laboratory settings.

Importance: As a low-complexity automated nucleic acid amplification test, the iFIND assay achieves the goal of simultaneously detecting isoniazid and fluoroquinolone resistance in approximately 90 min, perfectly meeting the TPP's core requirements for "rapid" and "simple operation." Its fully integrated system minimizes manual steps and contamination risk, making it highly suitable for use in resource-limited, lower-biosafety-level primary laboratories.

Targeting cell death pathways, including pyroptosis and necroptosis, has been shown to mitigate influenza virus infection severity. Here, we examined whether pyroptosis specifically driven by the pore-forming protein gasdermin E (GSDME) is involved in regulating influenza virus infection outcomes. We found that Gsdme^-/- mice showed similar weight loss and survival in severe A/PR/8/34 (H1N1) virus infections compared to WT counterparts. Likewise, lung dysfunction, histopathological damage, viral titers, and inflammatory cytokine levels were similar in the two groups. Global transcriptomic analysis also revealed similar inflammatory and antiviral gene expression programs in WT versus Gsdme^-/- mouse lungs at baseline and in response to infection. To confirm the generality of these findings, we infected mice with minimally mouse-adapted 2009 pandemic H1N1 virus and again observed similar weight loss, lung dysfunction, and mortality in WT and Gsdme^-/- mice. Our results overall demonstrate that GSDME contributes negligibly to the host response against H1N1 influenza virus, refining our understanding of cell death pathways in influenza pathogenesis.

Importance: Influenza virus infection activates multiple cell death pathways that shape disease outcomes. Here, we demonstrate that gasdermin E (GSDME)-mediated pyroptotic cell death does not significantly affect lung pathology or survival during severe H1N1 influenza virus infection. This finding contrasts with prior reports showing that GSDME worsens disease caused by H3N2 or H7N9 strains, as well as studies implicating gasdermin D in exacerbating H1N1 pathology. Thus, our data clarify that gasdermin family members contribute to influenza pathogenesis in a context-specific manner, underscoring the importance of considering viral diversity when evaluating the therapeutic potential of targeting cell death pathways.

The potable water dispenser (PWD) system plays a critical role as a source of drinking water for astronauts on the International Space Station (ISS). In this study, we examined the bioburden in the potable water produced by the PWD. The amount of extracellular polymeric substances (EPSs) in the PWD water was approximately 19 or 55 times greater than the bacterial count, and the EPS biomass accounted for approximately 24% or 86% of the bacterial biomass. Ralstonia pickettii consistently comprised approximately 70% or 80% of the bacteria for 3 years. Under simulated microgravity conditions, the isolated R. pickettii strains exhibited higher cell and EPS concentrations and higher total volume concentrations (average volume multiplied by concentration) of cell and EPS than under 1G conditions, whereas the average cell volume was smaller and the average EPS volume was larger. The ISS isolates showed higher EPS production and biofilm-formation abilities than terrestrial strains under nutrient-rich conditions and possessed high biofilm-formation ability comparable to those of terrestrial strains under nutrient-poor conditions. The ability of R. pickettii to produce EPS may play a crucial role in its adaptation to the water environment on the ISS.IMPORTANCEIn space habitation environments, the use of recycled water is indispensable, and ensuring its microbiological safety is essential. In this study, we elucidated the microbiological characteristics of water from the potable water dispenser (PWD) on the International Space Station (ISS). Our findings revealed that bacteria of the Ralstonia pickettii are the predominant species in PWD water and that extracellular polymeric substances (EPSs) constitute a large proportion of the biomass. Furthermore, the isolated R. pickettii was shown to possess high EPS production ability and strong biofilm-forming capacity. Since EPS plays a crucial role in biofilm formation, these abilities may be important factors enabling R. pickettii to adapt to the water environment of the ISS.

Although contact lens wear is widespread and known to affect the ocular surface, its impact on the ocular surface microbiome (OSM) remains poorly understood, with existing studies reporting conflicting findings. Additionally, the relationship between contact lens wear, tear proteome, and dry eye disease (DED) is unclear. In this study, we aimed to characterize the OSM (via whole-metagenome shotgun sequencing) and the tear proteome of 25 contact lens wearers and 23 age- and sex-matched controls. The dominant phyla were Actinobacteria, Proteobacteria, and Firmicutes, with Cutibacterium acnes being the most abundant species. No significant differences in microbial composition, diversity, or tear proteome were observed between contact lens wearers and controls. DED parameters (tear breakup time, Schirmer's test, tear osmolarity, and Ocular Surface Disease Index [OSDI]) also showed no significant differences, although contact lens wearers reported a trend toward higher subjective symptoms (OSDI). Sex-stratified analysis revealed a marginal difference in microbial beta diversity between male contact lens wearers and male controls, along with increased tear production in male contact lens wearers. Female contact lens wearers reported a higher OSDI compared to female controls. These findings suggest that contact lens wear does not significantly alter the OSM or tear proteome in healthy individuals, although sex-specific responses may warrant further investigation.IMPORTANCEContact lenses are worn by millions of people, yet the scientific literature contains conflicting reports about their impact on the microbial communities that are naturally present on the eye surface. This study addresses these knowledge gaps by examining both the eye microbiome and tear proteins using advanced sequencing and linking them to dry eye symptoms. Understanding the relationship between contact lens wear, natural eye bacteria, and tear composition is essential for resolving contradictory findings in the field. Additionally, identifying potential sex-specific differences in how individuals respond to contact lens wear could lead to more personalized approaches to contact lens management.

ESKAPE bacteria, namely Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp., are leading causes of hospital-acquired infections and a major therapeutic challenge due to multidrug resistance. Hospital surfaces and medical devices are critical reservoirs for the transmission of these pathogens to patients. Standard methods for detecting microorganisms in the hospital environment are culture-based, so they cannot identify bacteria in the viable but non-culturable (VBNC) state. VBNC bacteria remain metabolically active and potentially infectious, but they fail to grow in conventional, nutrient-rich culture media. Reversion from the VBNC to the cultivable state is termed resuscitation. To assess whether ESKAPE species enter the VBNC state upon desiccation on abiotic materials commonly utilized in clinical facilities and can be resuscitated, bacterial cells were desiccated for 1 week on glass, different plastics, cotton, and titanium surfaces, then resuscitated in a carbon-free buffer. After desiccation, all ESKAPE pathogens exhibited reduced cultivability, with species- and surface-dependent variability. Gram-positive ESKAPE species did not regain cultivability after resuscitation. Conversely, Gram-negative species reverted to the cultivable state, indicating a transition to the VBNC state in response to desiccation. Compared to the standard methodology for biocontamination control (EN 17141:2020), the resuscitation step prior to culture yielded a significantly greater recovery of Gram-negative ESKAPE bacteria in the VBNC state from both experimentally contaminated samples and environmental surfaces. These findings pose the need for environmental monitoring approaches capable of detecting VBNC pathogens on abiotic hospital surfaces.IMPORTANCEAccurate detection of microbial contamination in the hospital environment is fundamental for preventing nosocomial infections. Current protocols for environmental surveillance, however, rely almost exclusively on culture-based methods, which overlook bacteria in the viable but non-culturable (VBNC) state. This study demonstrates that clinically relevant Gram-negative ESKAPE pathogens can persist on hospital surfaces in the VBNC state, thereby evading conventional approaches for environmental control, resulting in substantial underestimation of the bacterial burden. We further show that a simple resuscitation step restores the cultivability of VBNC cells, improving their recovery rate, ultimately resulting in much greater sensitivity compared with conventional biocontamination control methods. These findings reveal a critical limitation of current environmental surveillance approaches and highlight the importance of integrating VBNC detection into monitoring protocols for achieving a more accurate assessment of surface contamination to strengthen infection prevention strategies.

Herpes simplex virus (HSV-1 and HSV-2) and varicella-zoster virus (VZV) cause cutaneous and mucocutaneous lesions. Primary infection and secondary reactivations affect the mouth, genitalia, and dermis at other bodily regions. Accurate clinical diagnosis without laboratory confirmation can be difficult since lesions caused by these viruses are nondescript, and areas of bodily infection can overlap. Rapid molecular test results have been shown to reduce the time to definitive diagnosis, providing additional opportunities for patient counseling, antiviral therapy, and appropriate infection prevention measures. A molecular, multiplexed HSV + VZV assay allows both viruses to be tested simultaneously from a single lesion swab. This could potentially enhance diagnostic accuracy through laboratory confirmation, thus minimizing dependence on clinical judgment alone. The recently Food and Drug Administration (FDA)-approved Savanna HSV 1+2/VZV multiplex assay has not been widely evaluated against other FDA-approved assays. This is the first report evaluating the clinical performance of the Savanna HSV 1+2/VZV assay compared to independent assays for HSV and VZV. Results indicated that the Savanna HSV 1+2/VZV assay was comparable to the Diasorin Simplexa HSV 1&2 Direct and VZV Direct assays.IMPORTANCELesion-causing viruses, herpes simplex (HSV-1 and HSV-2) and varicella-zoster virus (VZV), are common and difficult to distinguish clinically. Each can be found over any area of the body but have different treatment regimens and considerations for infectivity and future outbreak management. Laboratory analysis by molecular assay is the gold standard for these viruses, but it can take hours to days and is reliant on the clinician choosing the correct virus to test the first time, or risk being outside the treatment window. A rapid molecular assay that detects all three viruses simultaneously was developed and recently approved by the Food and Drug Administration (FDA). Here, we provide data highlighting the clinical performance of the Savanna HSV 1+2/VZV assay and its ability to detect across anatomical locations and ages. These data indicate that the Savanna assay is comparable to individual assays for each viral target, providing the opportunity for enhanced diagnostic accuracy of lesions.