Role of Type VI secretion system in pathogenic remodeling of host gut microbiota during Aeromonas veronii infection.

Intestinal microbial disturbance is a direct cause of host disease. The bacterial Type VI secretion system (T6SS) often plays a crucial role in the fitness of pathogenic bacteria by delivering toxic effectors into target cells. However, its impact on the gut microbiota and host pathogenesis is poorly understood. To address this question, we characterized a new T6SS in the pathogenic Aeromonas veronii C4. First, we validated the secretion function of the core machinery of A. veronii C4 T6SS. Second, we found that the pathogenesis and colonization of A. veronii C4 is largely dependent on its T6SS. The effector secretion activity of A. veronii C4 T6SS not only provides an advantage in competition among bacteria in vitro, but also contributes to occupation of an ecological niche in the nutritionally deficient and anaerobic environment of the host intestine. Metagenomic analysis showed that the T6SS directly inhibits or eliminates symbiotic strains from the intestine, resulting in dysregulated gut microbiome homeostasis. In addition, we identified three unknown effectors, Tse1, Tse2, and Tse3, in the T6SS, which contribute to T6SS-mediated bacterial competition and pathogenesis by impairing targeted cell integrity. Our findings highlight that T6SS can remodel the host gut microbiota by intricate interplay between T6SS-mediated bacterial competition and altered host immune responses, which synergistically promote pathogenesis of A. veronii C4. Therefore, this newly characterized T6SS could represent a general interaction mechanism between the host and pathogen, and may offer a potential therapeutic target for controlling bacterial pathogens.

Relationship between biofilm formation and antibiotic resistance of Klebsiella pneumoniae and updates on antibiofilm therapeutic strategies.

Klebsiella pneumoniae is a Gram-negative bacterium within the Enterobacteriaceae family that can cause multiple systemic infections, such as respiratory, blood, liver abscesses and urinary systems. Antibiotic resistance is a global health threat and K. pneumoniae warrants special attention due to its resistance to most modern day antibiotics. Biofilm formation is a critical obstruction that enhances the antibiotic resistance of K. pneumoniae. However, knowledge on the molecular mechanisms of biofilm formation and its relation with antibiotic resistance in K. pneumoniae is limited. Understanding the molecular mechanisms of biofilm formation and its correlation with antibiotic resistance is crucial for providing insight for the design of new drugs to control and treat biofilm-related infections. In this review, we summarize recent advances in genes contributing to the biofilm formation of K. pneumoniae, new progress on the relationship between biofilm formation and antibiotic resistance, and new therapeutic strategies targeting biofilms. Finally, we discuss future research directions that target biofilm formation and antibiotic resistance of this priority pathogen.

Genome-wide DNA N6-methyladenosine in Aeromonas veronii and Helicobacter pylori.

BACKGROUND: DNA N6-methyladenosine (6mA), as an important epigenetic modification, widely exists in bacterial genomes and participates in the regulation of toxicity, antibiotic resistance, and antioxidant. With the continuous development of sequencing technology, more 6mA sites have been identified in bacterial genomes, but few studies have focused on the distribution characteristics of 6mA at the whole-genome level and its association with gene expression and function. RESULTS: This study conducted an in-depth analysis of the 6mA in the genomes of two pathogenic bacteria, Aeromonas veronii and Helicobacter pylori. The results showed that the 6mA was widely distributed in both strains. In A. veronii, 6mA sites were enriched at 3' end of protein-coding genes, exhibiting a certain inhibitory effect on gene expression. Genes with low 6mA density were associated with cell motility. While in H. pylori, 6mA sites were enriched at 5' end of protein-coding genes, potentially enhancing gene expression. Genes with low 6mA density were closely related to defense mechanism. CONCLUSIONS: This study elucidated the distribution characteristics of 6mA in A. veronii and H. pylori, highlighting the effects of 6mA on gene expression and function. These findings provide valuable insights into the epigenetic regulation and functional characteristics of A. veronii and H. pylori.

Influence of COVID-19 pandemic on the epidemiology of Mycoplasma pneumoniae infections among hospitalized children in Henan, China.

Background: Increasing reports have indicated that non-pharmaceutical interventions to control the COVID-19 pandemic may also have an effect on the prevalence of other pathogens. Mycoplasma pneumoniae is an important atypical pathogen prevalent in children with high rates of macrolide resistance. The aim of this study was to investigate the epidemiological characteristics of M. pneumoniae infection in children before and during the COVID-19 pandemic. Methods: In this study, M. pneumoniae detection results were extracted from Henan Children's Hospital from 2018 to 2021. The epidemiological characteristics of pediatric M. pneumoniae infection were analyzed. Results: We found that the highest positive rate of M. pneumoniae infection was 11.00 % in 2018, 14.01 % in 2019, followed by 11.24 % in 2021 and 8.75 % in 2020 (p < 0.001). Most tested children had respiratory system manifestations, and pneumoniae was the most common diagnosis (53.23 %). An increase in the number of positive cases was observed with an increase in age, with a higher number of cases among children over 6 years old. No positive cases were identified among children aged 1-28 days. The decrease in the positive rate among children aged between1-6 years old in 2020 and 2021 was found to be statistically significant (p < 0.001). The pre-pandemic period demonstrated a higher incidence rate in the fall, whereas the summers and winters exhibited a significantly higher positive rate during the pandemic period (p < 0.001). Different regions in Henan also showed different epidemic patterns. Conclusions: In summary, strict pandemic measures influenced the spread of M. pneumoniae to some extent and changed demographic characteristics, including age, season and regional distribution. Continuous monitoring is required for the control and prevention of related diseases.

Acquisition of Type I methyltransferase via horizontal gene transfer increases the drug resistance of Aeromonas veronii.

Aeromonas veronii is an opportunistic pathogen that affects both fish and mammals, including humans, leading to bacteraemia, sepsis, meningitis and even death. The increasing virulence and drug resistance of A. veronii are of significant concern and pose a severe risk to public safety. The Type I restriction-modification (RM) system, which functions as a bacterial defence mechanism, can influence gene expression through DNA methylation. However, little research has been conducted to explore its origin, evolutionary path, and relationship to virulence and drug resistance in A. veronii. In this study, we analysed the pan-genome of 233 A. veronii strains, and the results indicated that it was 'open', meaning that A. veronii has acquired additional genes from other species. This suggested that A. veronii had the potential to adapt and evolve rapidly, which might have contributed to its drug resistance. One Type I methyltransferase (MTase) and two complete Type I RM systems were identified, namely AveC4I, AveC4II and AveC4III in A. veronii strain C4, respectively. Notably, AveC4I was exclusive to A. veronii C4. Phylogenetic analysis revealed that AveC4I was derived from horizontal gene transfer from Thiocystis violascens and exchanged genes with the human pathogen Comamonas kerstersii. Single molecule real-time sequencing was applied to identify the motif methylated by AveC4I, which was unique and not recognized by any reported MTases in the REBASE database. We also annotated the functions and pathways of the genes containing the motif, revealing that AveC4I may control drug resistance in A. veronii C4. Our findings provide new insight on the mechanisms underlying drug resistance in pathogenic bacteria. By identifying the specific genes and pathways affected by AveC4I, this study may aid in the development of new therapeutic approaches to combat A. veronii infections.

Roles of two-component regulatory systems in Klebsiella pneumoniae: Regulation of virulence, antibiotic resistance, and stress responses.

Klebsiella pneumoniae is an opportunistic pathogen belonging to the Enterobacteriaceae family, which is the leading cause of nosocomial infections. The emergence of hypervirulent and multi-drug resistant K. pneumoniae is a serious health threat. In the process of infection, K. pneumoniae needs to adapt to different environmental conditions, and the two-component regulatory system (TCS) composed of a sensor histidine kinase and response regulator is an important bacterial regulatory system in response to external stimuli. Understanding how K. pneumoniae perceives and responds to complex environmental stimuli provides insights into TCS regulation mechanisms and new targets for drug design. In this review, we analyzed the TCS composition and summarized the regulation mechanisms of TCSs, focusing on the regulation of genes involved in virulence, antibiotic resistance, and stress response. Collectively, these studies demonstrated that several TCSs play important roles in the regulation of virulence, antibiotic resistance and stress responses of K. pneumoniae. A single two-component regulatory system can participate in the regulation of several stress responses, and one stress response process may include several TCSs, forming a complex regulatory network. However, the function and regulation mechanism of some TCSs require further study. Hence, future research endeavors are required to enhance the understanding of TCS regulatory mechanisms and networks in K. pneumoniae, which is essential for the design of novel drugs targeting TCSs.

IgG4-related ophthalmic disease masquerading as ciliary body tumors and scleritis in both eyes: a case report.

BACKGROUND: To report a rare case of IgG4-related ophthalmic disease (IgG4-ROD) manifesting as intraocular masses and scleritis in both eyes in a 61-year-old male and to investigate the changes in multimodal imaging features of the lesion sites and helper T-cell type 1 (Th 1)/Th 2/Th 17 cytokine levels in the aqueous humor. CASE PRESENTATION: A patient with IgG4-ROD seemingly manifested with an intraocular tumor in the left eye and sequentially, with an inflammatory mass in the ciliary body and scleritis in the right eye. The patient complained of vision loss of 6 months duration in the left eye at his first visit. With a preliminary diagnosis of an intraocular tumor, enucleation of the left eyeball and histopathological examination were performed. Approximately 3 months later, the patient started to experience headache, eye pain, and declining vision in the right eye. Ophthalmic imaging revealed a ciliary mass and scleritis. Th 1/Th 2/Th 17 cytokine levels and multimodal imaging findings were analyzed before and after corticosteroid treatment. Histopathological examination and immunohistochemistry (IHC) of the enucleated left eye demonstrated lymphoplasmacytic infiltration with an IgG4+/IgG+ cell ratio of approximately 40%, pointing to the diagnosis of probable IgG4-ROD. Long-term treatment with corticosteroids led to significant improvement in the signs and symptoms of the left eye. Th 1/Th 2/Th 17 cytokine profile monitoring of the aqueous humor and multimodal imaging of the right eye showed gradual regression of the mass and attenuation of ocular inflammation during treatment. CONCLUSIONS: Patients with an atypical presentation of IgG4-ROD, such as intraocular masses and scleritis, are likely to experience a significant delay in diagnosis. This case demonstrates the significance of IgG4-ROD in the differential diagnosis of intraocular tumors and ocular inflammation. IgG4-RD is a newly diagnosed disease with multi-organ involvement and little is known about its pathogenesis, particularly in the eye. The present case will open new challenges in the clinico-pathological diagnosis and research of this disease. Combined investigations of multimodal imaging and cytokine level detection of intraocular fluid provide a new and effective way to monitor disease progression.

Species-level respiratory microbiome profiling for etiologic diagnosis of children pneumonia using full length 16S rRNA gene sequencing.

PURPOSE: The study was conducted to analyze the role of respiratory microbiome composition in children pneumonia etiology diagnosis. METHODS: The bronchoalveolar lavage fluid bacterial community between the Mycoplasma pneumoniae pneumonia (MP group, n â€‹= â€‹13) and the pathogen negative pneumonia (N group, n â€‹= â€‹20) children were compared using the full-length 16S rRNA gene sequencing. RESULTS: Distinct bacterial communities were identified in two groups and lower α-diversity was revealed in the MP patients indicating the lower abundance microbiota composition. Dominant bacteria were Mycoplasma and Mycoplasma pneumoniae for MP patients at genus and species levels. Possible pathogens were characterized in 17 out of 20 patients in the N group by detection of higher abundance using the 16S rRNA gene sequencing. CONCLUSIONS: The high taxonomic resolution of full-length 16S rRNA gene sequencing assists in improving characterization of potential pathogens, and more studies are necessary to further evaluate the prognostic roles of specific bacteria in the pathogenicity of pneumonia.

Epidemiological characteristics and antibiotic resistance mechanisms of Streptococcus pneumoniae: An updated review.

Streptococcus pneumoniae (S. pneumoniae, pneumococcus) is a Gram-positive bacterium, which can cause a variety of diseases including otitis media, nasosinusitis, pneumonia, bacteremia and meningitis. To prevent and control pneumococcus diseases, pneumococcal conjugate vaccines (PCVs) were developed and widely implemented worldwide. The introduction of PCVs reduced the infections caused by PCV serotypes, while serotype replacements affected vaccine effectiveness. S. pneumoniae has developed resistance to multiple antibiotics including penicillin, macrolides, fluoroquinolone, and sulfamethoxazole-trimethoprim. In turn, infections caused by antibiotic resistant strains can affect the treatment of related diseases. Genetic functional studies, molecular detection, and molecular characterization of newly identified mechanisms have been updated in recent years. Hence, this review aims to summarize the serotype distribution, epidemiology and antibiotic resistance mechanism of S. pneumoniae in the vaccine era. A greater understanding of the epidemiological features and antibiotic resistance mechanisms could ultimately assist clinical treatment and prevent the spread of antibiotic resistance strains.

Global spread of carbapenem-resistant Enterobacteriaceae: Epidemiological features, resistance mechanisms, detection and therapy.

Bacterial drug resistance has become a global public health threat, among which the infection of carbapenem-resistant Enterobacterales (CRE) is one of the top noticeable issues in the global anti-infection area due to limited therapy options. In recent years, the prevalence of CRE transmission around the world has increased, and the transmission of COVID-19 has intensified the situation to a certain extent. CRE resistance can be induced by carbapenemase, porin, efflux pump, penicillin-binding protein alteration, and biofilm production. Deletion, mutation, insertion, and post-transcriptional modification of corresponding coding genes may affect the sensitivity of Enterobacterales bacteria to carbapenems. Clinical and laboratory methods to detect CRE and explore its resistance mechanisms are being developed. Due to the limited options of antibiotics, the clinical treatment of CRE infection also faces severe challenges. The clinical therapies of CRE include single or combined use of antibiotics, and some new antibiotics and treatment methods are also being developed. Hence, this review summarizes the epidemiology, resistance mechanisms, screening and clinical treatments of CRE infection, to provide references for clinical prevention, control and treatment of CRE infection.

Anxiety and depression status prior to radioactive iodine therapy among differentiated thyroid cancer patients during the COVID­19 pandemic.

OBJECTION: The psychological health of thyroid cancer patients cannot be ignored; however, few studies have been conducted on the psychological status and influencing factors of thyroid cancer patients before radioactive iodine (RAI) therapy. The aim of this study was to investigate the incidence and risk factors for anxiety and depression in thyroid cancer patients prior to RAI therapy. METHODS: Clinical data were collected from patients with differentiated thyroid cancer (DTC) patients preparing for RAI therapy. Anxiety and depression were measured before RAI therapy using the Generalized Anxiety Disorder Questionnaire (GAD-7) and Patient Health Questionnaire (PHQ-9). We used the chi-square test and logistic regression analysis to identify independent risk factors for anxiety and depression. RESULTS: A total of 112 patients with thyroid cancer were included. Of these, 72.32% (n = 81) were female, with a mean age of 41.50 years. Anxiety and depression were reported by 46 (41.08%) and 38 (33.93%) patients, respectively. Based on the chi-square test and univariate logistic regression analysis, being female and having ever-experienced RAI therapy were significant risk factors for anxiety and depression among DTCs prior to RAI therapy. On multivariable analysis, the results of model 2 which included age, sex, education level, and ever suffering radioactive iodine therapy showed that being female was markedly associated with anxiety and depression in these patients, while having ever undergone RAI therapy was significantly related to anxiety but not depression. CONCLUSIONS: The incidence of anxiety and depression among patients with DTC prior to RAI therapy were 41.08% and 33.93%, respectively. Being female and having ever experienced RAI therapy significantly influenced anxiety and depression. Based on these findings, anxiety and depression assessment should be an important part of pre-RAI therapy in patients with DTC, and appropriate psychological nursing intervention can be carried out for key patients.

Antimicrobial activity of CT-K3K7, a modified peptide by lysine substitutions from ctry2459 - A Chaerilus tryznai scorpion venom peptide.

Antimicrobial peptides (AMPs) have started to garner more interest as novel antimicrobial agents. The scorpion venom peptide ctry2459 was modified to CT-K3K7 by lysine substitutions at the 3rd and 7th positions to increase the cationic properties. We discovered that the modified peptides CT-K3K7 had improved antibacterial activity, higher thermal stability, as well as lower hemolytic activity. It can kill S. aureus and P. aeruginosa rapidly, and reduce the production of biofilm and live bacterial residues in biofilm in vitro. CT-K3K7 has also been demonstrated to decrease bacterial counts, abscess area, and inflammatory cell infiltration in the mouse subcutaneous abscess models that were duplicated by S. aureus and P. aeruginosa. CT-K3K7 has difficulty in inducing S. aureus and P. aeruginosa to develop drug resistance, which may be related to the bactericidal properties. CT-K3K7 increases cationic properties by lysine substitutions can increase the electrostatic force between the peptides and the bacterial surface, which can lead to an increase in bacterial membrane permeability and DNA binding. In conclusion, the modified peptide CT-K3K7 enhances the antimicrobial activity and can be a novel antimicrobial agent candidate for the treatment of infections by S. aureus and P. aeruginosa.

Molecular beacon based real-time PCR p1 gene genotyping, macrolide resistance mutation detection and clinical characteristics analysis of Mycoplasma pneumoniae infections in children.

BACKGROUND: Mycoplasma pneumoniae can be divided into different subtypes on the basis of the sequence differences of adhesive protein P1, but the relationship between different subtypes, macrolide resistance and clinical manifestations are still unclear. In the present study, we established a molecular beacon based real-time polymerase chain reaction (real-time PCR) p1 gene genotyping method, analyzed the macrolide resistance gene mutations and the relationship of clinical characteristics with the genotypes. METHODS: A molecular beacon based real-time PCR p1 gene genotyping method was established, the mutation sites of macrolide resistance genes were analyzed by PCR and sequenced, and the relationship of clinical characteristics with the genotypes was analyzed. RESULTS: The detection limit was 1-100 copies/reaction. No cross-reactivity was observed in the two subtypes. In total, samples from 100 patients with positive M. pneumoniae detection results in 2019 and 2021 were genotyped using the beacon based real-time PCR method and P1-1 M. pneumoniae accounted for 69.0%. All the patients had the A2063G mutation in the macrolide resistance related 23S rRNA gene. Novel mutations were also found, which were C2622T, C2150A, C2202G and C2443A mutations. The relationship between p1 gene genotyping and the clinical characteristics were not statistically related. CONCLUSION: A rapid and easy clinical application molecular beacon based real-time PCR genotyping method targeting the p1 gene was established. A shift from type 1 to type 2 was found and 100.0% macrolide resistance was detected. Our study provided an efficient method for genotyping M. pneumoniae, valuable epidemiological monitoring information and clinical treatment guidance to control high macrolide resistance.

One-Month Outcomes of Intravitreal Anti-VEGF vs. Dexamethasone Implant in the Treatment of Diabetic Macular Edema in Vitrectomized Eyes.

Objectives: To compare short-term effect of intravitreal ranibizumab with dexamethasone implant for diabetic macular edema (DME) in vitrectomized eyes. Methods: Single-center, prospective, randomized study of vitrectomized eyes with DME. Study eyes were divided into two groups, receiving ranibizumab (IVV group, n = 35 eyes) or dexamethasone implant (IVD group, n = 35 eyes) respectively. Patients were evaluated at baseline, Week 1 and Month 1. The main outcome measures included best-corrected visual acuity (BCVA), central retinal thickness (CRT) and intraocular pressure (IOP). Results: BCVA and CRT were similar in the two groups at baseline. At Week 1, the CRT improvement was significant in two groups (P = 0.041 in IVV group, P = 0.030 in IVD group), but at Month 1, only IVD group had significant improvement in CRT (P < 0.001). And BCVA gains were significant at Week 1 (P = 0.029) and Month 1 (P = 0.001) in IVD group, whereas IVV group did not show significant BCVA gains (P = 0.056 at Week1, P = 0.166 at Month 1). The changes of BCVA and CRT were significantly higher in IVD group than IVV group at Month1, but the changes were not significant at Week1. Conclusions: Comparing to anti-VEGF therapy, DEX implant is more effect in improving BCVA and reducing CRT in vitrectomized eyes at 1 month, which indicated DEX implant is a better strategy.

Comparison of Inflammatory and Angiogenic Factors in the Aqueous Humor of Vitrectomized and Non-Vitrectomized Eyes in Diabetic Macular Edema Patients.

Objectives: To compare the aqueous concentrations of inflammatory and angiogenetic factors in vitrectomized vs. non-vitrectomized eyes with diabetic macular edema (DME). Methods: Aqueous samples were obtained from 107 eyes with DME before intravitreal injection of anti-VEGF, 36 eyes with previous pars plana vitrectomy (PPV) combined with pan-retinal endolaser photocoagulation (PRP), and 71 treatment-naïve. Interleukin (IL)-6, IL-8, interferon-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, and vascular endothelial growth factor (VEGF) were measured by cytometric bead array (CBA). Optical coherence tomography (OCT) was used for measuring central retinal thickness (CRT). Results: IL-6, IL-8, IP-10, and MCP-1 in aqueous humor of DME vitrectomized eyes were significantly higher than in non-vitrectomized DME eyes, while VEGF was lower than in non-vitrectomized DME eyes. VEGF in aqueous humor significantly correlated with CRT for DME in non-vitrectomized DME eyes. IL-6, IL-8, IP-10, and MCP-1 in aqueous humor were not significantly associated with VEGF for DME in vitrectomized eyes. Conclusions: Inflammation might play an important role in the pathogenesis of DME in vitrectomized eyes. Moreover, inflammation might play a central role in the development of DME via the VEGF-independent pathway. Thus, anti-inflammatory therapy might be a strategy for DME in vitrectomized eyes.

Factors That Influence Compliance to Long-Term Remote Ischemic Conditioning Treatment in Patients With Ischemic Stroke.

Objectives: To investigate the treatment compliance of patients with ischemic stroke to remote ischemic conditioning (RIC) and to determine the factors that influence compliance. Methods: We conducted a retrospective study of patients with ischemic stroke who were treated with RIC. Treatment compliance was determined and analyzed in patients who had received 1 year of RIC training. Factors that influenced patient compliance were also determined using univariate and multivariate regression analyses. Results: Between March 2017 and February 2018, 91 patients were recruited into this study. The mean (±SD) age was 57.98 ± 10.76 years, and 78 (85.7%) patients were male. The baseline Kolcaba comfort scale of patients with good compliance scores were higher than those with poor compliance. The scores of the four dimensions in the scale and the total score are as follows: physiological dimensions, 15.0 (12.0,17.0) vs 17.0 (13.0,19.0); psychological dimensions, 30.0 (25.0,34.0) vs 31.0 (27.0,35.0); sociological dimensions, 20.0 (18.0,24.0) vs 21.0 (18.0,23.0); environmental dimensions, 19.0 (12.0,24.0) vs 20.0 (17.0,22.0); and total points, 82.0 (69.0,94.0) vs 91.0 (78.0,98.0). the differences between the groups were significant (p < 0.05), except for the sociological dimensions. A history of hypertension, number of follow-ups, and the physiological, psychological, and environmental dimensions of the comfort scale were related to patient compliance, out of which the number of follow-ups (Adjusted OR = 2.498, 95% confidence interval (CI) 1.257-4.964) and the physiological discomfort (Adjusted OR = 1.128, 95% CI 1.029-1.236) independently influenced compliance (p < 0.05). Conclusion: In patients with ischemic cerebrovascular disease who were treated with RIC, the number of follow-up visits and physiological discomfort associated with RIC treatment independently influenced patient compliance. Further studies are needed to investigate the RIC protocols and their corresponding nursing models.