Frontiers in Cellular and Infection Microbiology最新文献

Staphylococcus aureus is a significant pathogen in dairy animals, particularly when it infects the mammary gland; however, its prevalence among dairy goats in China remains poorly understood. This study aimed to investigate the distribution and characteristics of S. aureus isolates in dairy goats across China. A total of 515 milk samples were collected from goats diagnosed with mastitis in 14 provinces. These samples underwent bacterial isolation and identification, capsular polysaccharides typing, spa typing, antimicrobial susceptibility testing, and assessment of antimicrobial resistance and virulence gene. The findings revealed the isolation of 61 S. aureus strains. The highest prevalence rate was recorded in 2018, at 20.4% (11 out of 54 samples), while the lowest prevalence rate was noted in 2023, at 5.2% (3 out of 58 samples). Among the five regions studied, southern China exhibited the highest prevalence rate of 17.5% (10 out of 57 samples), whereas northeastern China showed the lowest rate at 8.2% (8 out of 97 samples). Capsular polysaccharide type 5 emerged as the most prevalent, accounting for 52.5%, and spa type t521 was identified most frequently, at 19.7%. Notably, 52 isolates (85.2%) demonstrated multidrug resistance, displaying resistance to three or more antibiotics. The resistance rates of S. aureus isolates were significantly high to penicillin (95.1%), followed by enrofloxacin (82.0%), kanamycin (78.7%), and levofloxacin (77.0%). Trimethoprim-sulfamethoxazole exhibited the lowest resistance rate at 11.5%. Resistance rates varied across the five different regions. Additionally, eight genes associated with resistance to six classes of antimicrobials were detected, with the blaZ gene (93.4%) being the most prevalent at 93.4%. Furthermore, nine virulence-associated genes were identified, with clfA being the most common virulence gene, present in all isolates. In conclusion, most S. aureus isolates were multiresistant with diverse resistance patterns. Those diverse antimicrobial resistance profiles associated with corresponding resistance genes (p < 0.05) were reported for the first time in S. aureus from caprine mastitis. Sulfonamides could be prioritized preferentially for the treatment of S. aureus mastitis.

Female health and the microbiota of the reproductive tract are closely associated. The research scope on reproductive tract microbiota extends from the vaginal to the upper reproductive tract and from infectious diseases to various benign and malignant gynecological and obstetrical diseases. The primary focus of this paper was to evaluate the most recent findings about the role of reproductive tract microbiota in gynecological diseases, including endometrial polyps, uterine fibroids, endometriosis, adenomyosis, endometrial hyperplasia, and endometrial carcinoma. Different stages of gynecological diseases have diverse microbiota in the female reproductive tract, and some specific bacteria may help the disease progress. For example, Fusobacterium may exacerbate endometriosis, while treatments that target microbiota, such as antibiotics, probiotics, and flora transplantation, showed some efficacy in the experiment. These findings indicate the wonderful prospect of this field. Additionally, we have discussed how microbiome research can improve our understanding of the interactions between reproductive tract microorganisms and hosts, aid in the screening and diagnosis of gynecological diseases, and direct the development of preventive and therapeutic strategies aimed at maintaining and restoring a healthy reproductive tract microbiota when combined with other technologies like transcriptome and proteome, in vitro cultured cells, and animal models.

Like other tuberculous and nontuberculous mycobacterial pathogens of human lung such as Mycobacterium tuberculosis and M. abscessus, M. avium is likely exposed to a variety of stressors during infection, including hypoxic conditions inside activated macrophages and in the avascular necrotic regions of granulomas. How M. avium survives hypoxic stress to establish a chronic infection is currently not well understood. Using RNA-sequencing, we here show that M. avium grown under progressive microaerophilic conditions activates more than 4-fold a subset of 16 genes, the expression of 13 of which is dependent on the two-component system regulator DosRS. A subset of M. avium DosR regulon genes was confirmed to also be activated upon exposure to nitric oxide. Although a second sensor kinase besides DosS has been proposed to function with the transcriptional regulator DosR in M. avium, we show that this other kinase cannot compensate for a deficiency in DosS. Loss of dosRS expression in M. avium led to a significant reduction in viability under hypoxia that was more marked at acidic than at neutral pH. Unlike the situation in M. abscessus, however, loss of DosRS did not significantly impact the ability of M. avium to establish a drug tolerant state in vitro or form biofilms under host relevant conditions. Collectively, these results are suggestive of a lesser impact of DosRS on the ability of M. avium to develop antibiotic tolerance compared to other nontuberculous mycobacteria. The M. avium dosRS mutant further showed no signs of virulence attenuation in murine macrophages and in chronically infected immunocompetent BALB/c mice.

Introduction: Clinicians encounter significant challenges in quickly and accurately identifying the bacterial species responsible for patient bacteremia and in selecting appropriate antibiotics for timely treatment. This study introduces a novel approach that combines immune response data from routine blood counts with assessments of immune cell activation, specifically through quantitative measurements of Rho family GTPase activity. The combined data were used to develop a machine-learning model capable of distinguishing specific classes of bacteria and their associations.

Methods: We aimed to determine whether different classes of bacteria elicit distinct patterns of host immune responses, as indicated by quantitative differences in leukocyte populations from routine complete blood counts with differential. Concurrently, we conducted quantitative measurements of activated Rac1 (Rac1•GTP) levels using a novel 'G-Trap assay' we developed. With the G-Trap, we measured Rac1•GTP in peripheral blood monocytes (PBMC) and polymorphonuclear (PMN) cells from blood samples collected from 28 culture-positive patients and over 80 non-infected patients used as controls.

Results: Our findings indicated that 18 of the 28 patients with bacteremia showed an increase of ≥ 3-fold in Rac1•GTP levels compared to the controls. The remaining ten patients with bacteremia exhibited either neutrophilia or pancytopenia and displayed normal to below-normal Rac1 GTPase activity, which is consistent with bacteria-induced immunosuppression. To analyze the data, we employed partial least squares discriminant analysis (PLS-DA), a supervised method that optimizes group separation and aids in building a novel machine-learning model for pathogen identification.

Discussion: The results demonstrated that PLS-DA effectively differentiates between specific pathogen groups, and external validation confirmed the predictive model's utility. Given that bacterial culture confirmation may take several days, our study underscores the potential of combining routine assays with a machine-learning model as a valuable clinical decision-support tool. This approach could enable prompt and accurate treatment on the same day that patients present to the clinic.

Introduction: Previous studies have suggested that dietary organic iron offers health advantages compared to its inorganic counterpart. However, the effects of iron hydroxy methionine analog chelate (Fe-HMA) supplementation in weaned piglets have not been fully explored. Therefore, this study aimed to investigate the effects of replacing ferrous sulfate with Fe-HMA as the iron source on serum biochemistry, antioxidant capacity, and gut microbiota in weaned piglets.

Methods: One hundred and twenty weaned piglets were randomly allocated to two treatment groups. Each group contained four replicates, with 15 pigs per replicate. Piglets were fed either 100 mg Fe/kg in the form of ferrous sulfate (Fe-sulfate group) or 50 mg Fe/kg in the form of Fe-HMA (Fe-HMA group) as the iron source for 28 days.

Results and discussion: Results showed that supplementing Fe-HMA as an iron source significantly increased the levels of triglycerides and glucose in portal venous serum, albumin in both serum and portal venous serum and decreased serum low-density lipoprotein level in weaned piglets. Additionally, Fe-HMA supplementation significantly reduced serum and liver malondialdehyde levels, while increasing catalase (CAT), glutathione peroxidase (GSH-Px), total superoxide dismutase, and manganese superoxide dismutase levels in serum, as well as GSH-Px and CAT levels in the liver. Moreover, Fe-HMA regulated the intestinal microbiota composition, notably increasing the relative abundance of Proteobacteria and decreasing microbes involved in aromatic_compound_degradation. In conclusion, dietary replacing inorganic iron with Fe-HMA improved metabolic parameters and antioxidant capacity, and regulated gut microbiota composition in weaned piglets.

Objective: The aim of this study was to examine the impact of obesity on the diagnosis of periprosthetic joint infections (PJI) by assessing the levels and diagnostic efficacy of biomarkers.

Methods: A total of 254 patients were divided into obese group (n=59) and non-obese group (n=195) according to BMI. Each group was further divided into the PJI group and the AF group. Data on CRP, ESR, fibrinogen, D-dimer, CRP-albumin ratio (CAR), CRP-lymphocyte ratio (CLR), and CRP-monocyte ratio (CMR) were collected from all patients. ROC curve was performed to evaluate the diagnostic values of these biomarkers.

Results: The levels of biomarkers were significantly higher in PJI patients compared to the AF patients in both the obese and non-obese groups (P < 0.001), but the levels of biomarkers were similar between the obese and non-obese groups. In the obese group, CRP exhibited the highest diagnostic value (AUC=0.982). In the non-obese group, CAR demonstrated the highest diagnostic value (AUC =0.935). Subgroup analysis showed no significant differences in biomarker levels (P > 0.05).

Conclusions: Obesity did not affect biomarker levels in patients with PJI. But for obese patients, the diagnostic thresholds for CRP and ESR are higher, and clinical diagnosis should be careful to avoid false positives. CRP and CAR were identified as the most effective biomarkers for diagnosing PJI in the obese and non-obese groups, respectively.

Introduction: Body mass index (BMI) is considered an important factor in tumor prognosis, but its role in gastric cancer (GC) remains controversial. There is a lack of studies exploring the effect of BMI on gastric cancer from the perspective of intratumoral microbiota. This study aimed to compare and analyze the differences in and functions of intratumoral microbiota among GC patients with varying BMIs, aiming to ascertain whether specific microbial features are associated with prognosis in low-BMI (LBMI) gastric cancer patients.

Methods: A retrospective analysis of the clinicopathological features and prognosis of 5567 patients with different BMIs was performed between January 2010 and December 2019. Tumor tissues from 189 GC patients were collected for 16S rRNA sequencing, 64 samples were selected for transcriptome sequencing, and 57 samples were selected for untargeted metabolomic analysis.

Results: Clinical cohort analysis revealed that GC patients with a low BMI presented poorer clinical and pathological characteristics than those with a non-low-BMI (NLBMI). LBMI was identified as a significant independent risk factor for adverse prognosis, potentially exerting immunosuppressive effects on postoperative adjuvant chemotherapy. 16S rRNA sequencing revealed no significant differences in the alpha and beta diversity of the intratumoral microbiota between the two groups of GC patients. However, LEfSe analysis revealed 32 differential intratumoral microbiota between the LBMI and NLBMI groups. Notably, the genus Abiotrophia was significantly enriched in the LBMI group. Further in-depth analysis indicated that the genus Abiotrophia was inversely associated with eosinophils, P2RY12, and SCN4B genes, and positively linked with LGR6 in LBMI gastric cancer patients. Metabolomic assessments revealed that LBMI was positively associated with purine metabolites, specifically guanine and inosine diphosphate (IDP).

Discussion: In conclusion, LBMI is an independent risk factor for poor prognosis in gastric cancer patients and may have an inhibitory effect on postoperative adjuvant chemotherapy. Intratumor flora of gastric cancer patients with different BMI levels differed, with different immune cell infiltration and metabolic characteristics. The genus Abiotrophia may promote gastric cancer development and progression by regulating eosinophils and the purine metabolism pathway, which provides a new idea for the precise treatment of gastric cancer.

Background: Cancer patients are highly susceptible to infections due to their immunocompromised state from both the malignancy and intensive treatments. Accurate and timely identification of causative pathogens is crucial for effective management and treatment. Targeted next-generation sequencing (tNGS) has become an important tool in clinical infectious disease diagnosis because of its broad microbial detection range and acceptable cost. However, there is currently a lack of systematic research to evaluate the diagnostic value of this method in cancer patients.

Methods: To evaluate the diagnostic value of tNGS for cancer patients with pneumonia, a retrospective analysis was conducted on 148 patients with suspected pneumonia who were treated at the Henan Cancer Hospital. The tNGS results were compared with conventional microbiological tests (CMT) and clinical diagnoses based on symptoms and imaging studies to assess the diagnostic performance of tNGS in cancer patients with pneumonia.

Results: Among these 148 patients, 130 were ultimately diagnosed with pneumonia. tNGS demonstrated significantly higher sensitivity (84.62% vs. 56.92%) and diagnostic accuracy (85.81% vs. 62.16%) compared to the CMT method. The tNGS method identified more pathogens than CMT method (87.50% vs 57.14%), regardless of whether they were bacteria, fungi, or viruses, primarily due to its broader pathogen detection range and higher sensitivity compared to the CMT method. tNGS had significantly higher diagnostic accuracy for Pneumocystis jirovecii and Legionella pneumophila than the CMT method, but for most pathogens, tNGS showed higher sensitivity but with a correspondingly lower specificity compared to CMT.

Conclusion: tNGS demonstrates higher sensitivity and a broader pathogen detection spectrum compared to CMT, making it a valuable diagnostic tool for managing pneumonia in cancer patients.

Despite decades of control efforts, the prevalence of schistosomiasis remains high in many endemic regions, posing significant challenges to global health. One of the key factors contributing to the persistence of the disease is the complex life cycle of the Schistosoma parasite, the causative agent, which involves multiple stages of development and intricate interactions with its mammalian hosts and snails. Among the various stages of the parasite lifecycle, the deposition of eggs and their migration through host tissues is significant, as they initiate the onset of the disease pathology by inducing inflammatory reactions and tissue damage. However, our understanding of the mechanisms underlying Schistosoma egg extravasation remains limited, hindering efforts to develop effective interventions. Microphysiological systems, particularly organ-on-a-chip systems, offer a promising approach to study this phenomenon in a controlled experimental setting because they allow the replication of physiological microenvironments in vitro. This review provides an overview of schistosomiasis, introduces the concept of organ-on-a-chip technology, and discusses its potential applications in the field of schistosomiasis research.

For successful colonization, pathogenic bacteria need to adapt their metabolism and virulence functions to challenging environments within their mammalian hosts that are frequently characterized by low oxygen (O₂) tensions. Upon oral ingestion, the human pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) is exposed to changing O₂ and pH levels. Low concentrations of O₂, which can enhance the virulence of enteroinvasive pathogens, facilitate the expression of the type three secretion system (T3SS-1) encoded by the Salmonella pathogenicity island 1 (SPI-1) that is critical for enteroinvasion and pathogenicity of S. Typhimurium. To study the impact of key environmental cues of the intestine when Salmonella encounter enterocytes, we established an in vitro growth model, which allows shifting the concentration of O₂ from 0.5% to 11% and the pH from 5.9 to 7.4 in the presence of acetate and the alternative electron acceptor nitrate. Compared to normoxia, hypoxia elevated the expression of SPI-1 genes encoding T3SS-1 translocators and effectors, which resulted in higher invasion and effector translocation in epithelial cells. While hypoxia and pH shift only marginally altered the gene expression of SPI-1 regulators, including the SPI-1 repressor hilE, hypoxia and pH shift completely incapacitated HilE in a post-translational manner, ultimately promoting SPI-1 activity. From these findings, we conclude that O₂-dependent HilE function allows for ultrasensitive adaptation of SPI-1 activity in environments with varying O₂ availability such as the intestinal tract.