Frontiers in Cellular and Infection Microbiology最新文献

Background: During severe acute pancreatitis (SAP), damage to the intestinal mucosal barrier and translocation of intestinal pathogenic bacteria are key mechanisms that accelerate the disease progression of SAP. Chaihuang Qingyi Huoxue Granule (CH) is a herbal formula used in the clinical treatment of SAP. This study aims to investigate the role of CH in regulating gut microbiota and intestinal mucosal barrier in SAP rats.

Methods: Sodium taurocholate (3.5%) was retrogradely perfused into the biliopancreatic duct to establish the model of SAP in rats. CH (4.4 g/kg) was administered by gavage. Serum amylase, lipase, and endotoxin levels were measured. Hematoxylin-eosin (HE) staining was used to observe morphological changes in the pancreas and colon. The expression of zona occludens-1 (ZO-1) and occludin in the colon was examined by immunohistochemistry (IHC) and western blot. 16S rDNA gene sequencing was used to analyze the gut microbiota of the rats. The content of short-chain fatty acids (SCFAs) in the intestinal contents of the rats was determined by gas chromatography-mass spectrometry (GC-MS).

Results: CH reduced serum amylase, lipase, and endotoxin levels in SAP rats, alleviated pathological damage in the pancreas and colon, and restored the expression of ZO-1 and occludin. Moreover, CH alleviated gut microbiota dysbiosis in SAP rats, with restored gut microbiota diversity and structure. At the phylum level, the relative abundance of Firmicutes and Bacteroidetes increased, while that of Proteobacteria decreased. At the genus level, the abundance of Ruminococcus 1, Parabacteroides, Prevotellaceae UCG-001, Lachnospiraceae NK4A136 group, and Lactobacillus increased, while that of Escherichia-Shigella, Enterococcus, and Enterobacter decreased. In addition, CH increased the levels of SCFAs in the intestinal contents of SAP rats.

Conclusion: CH ameliorates SAP by maintaining the homeostasis and diversity of the gut microbiota, increasing the levels of SCFAs, and repairing the intestinal mucosal barrier.

Background: Most children in Argentina received only the initial COVID-19 vaccine series, with presumed hybrid immunity after multiple Omicron waves. However, the durability of immune memory, particularly in immunocompromised (IC) children, remains poorly studied.

Methods: A cohort of IC (n=45) and healthy children (HC, n=79) was assessed between 13 to 17 months after receiving two or three doses of BBIBP-CorV and/or BNT162b2. Plasma anti-spike IgG, neutralizing activity and antigen-specific CD4+ and CD8+ T cells against Wuhan and Omicron BA.5 variants were assessed.

Results: Most children remained seropositive after two vaccine doses, but compared with HC, IC exhibited lower neutralizing titers against both Wuhan and Omicron BA.5, particularly those vaccinated with BBIBP-CorV. Even after three vaccine doses, IC showed weaker neutralizing antibody response, CD8+ T cell responses and lower IFN-γ production compared with HC. Integrated analysis of neutralizing antibodies, memory CD4⁺, and CD8⁺ T cells revealed a weak immune memory among IC with an important compromise in memory CD8⁺ T cell responses.

Conclusions: Immunity can last up to 17 months, but reduced effectiveness against new variants highlights the need for updated COVID-19 vaccines, especially for IC children. Additional efforts are essential to enhance vaccination coverage and protect this vulnerable population.

In natural ecosystems, parasites often infect multiple host species, particularly when hosts share habitats, facilitating host-to-host transmission and altering traditional host-parasite coevolution dynamics. This study examines the microsporidian parasite Nosema ceranae in Eastern honey bees (Apis cerana) and Western honey bees (Apis mellifera), assessing its virulence and proliferation dynamics. Using inoculation experiments, we measured bee mortality and parasite spore loads to infer virulence and proliferation. Additionally, time-series transcriptome analysis of both bees and parasites provide insights into host-pathogen interactions. The results reveal that N. ceranae produces more spores with lower mortality in A. mellifera but causes higher mortality with lower spore production in A. cerana. The parasite also suppresses host gene expression, with stronger suppression observed in A. cerana. These findings suggest that N. ceranae is adapted for low virulence and high proliferation in A. mellifera but exhibits high virulence and limited proliferation in A. cerana. This study highlights the evolution of distinct trade-offs between virulence and proliferation in a multi-host system, offering valuable insights into parasite-host dynamics and their ecological implications.

Introduction: The incidence of malaria in Indonesia has declined significantly over the last few decades. Thus, a demand for more sensitive techniques to describe low levels of transmission in the country is important. This study was conducted to evaluate antibody response to Plasmodium falciparum and Plasmodium vivax in an area nearing elimination in North Sumatera Province, Indonesia.

Methods: A cross-sectional survey was conducted in Langkat district, North Sumatera Province, in June 2019. Basic demographic data and filter paper blood spots were collected from 339 participants. Antibody responses to two P. falciparum (PfAMA-1 and PfMSP-1₁₉) and two P. vivax (PvAMA-1 and PvMSP-1₁₉) antigens were measured using indirect enzyme-linked immunosorbent assay (ELISA). Seroconversion rates (SCR) were estimated by fitting a simple reversible catalytic model to seroprevalence data for each antibody. Multiple logistic regression was used to investigate factors associated with exposure.

Results: The overall malaria seroprevalence was 10.6% for PfAMA-1, 13% for PfMSP-1₁₉, 18.6% for PvAMA-1, and 7.4% for PvMSP-1₁₉. Seropositive individuals for P. falciparum (PfAMA-1/PfMSP-1₁₉) and P. vivax (PvAMA-1/PvMSP-1₁₉) were similar at 20.7%, with no significant differences observed between age groups (p > 0.05). Based on the reversible catalytic model, the calculated SCRs indicated a higher level of P. falciparum transmission than P. vivax using all tested antigens. In the adjusted model, only spending nights in the forest was associated with P. vivax seropositivity (odd ratio: 3.93, p < 0.001).

Conclusion: The analysis of community-based serological data helps describe the similar levels of P. falciparum and P. vivax transmission in the Langkat district. The use of a serological approach enhances the detection of past exposure, aiding in the identification of epidemiological risk factors and malaria surveillance in low transmission settings in Indonesia.

Introduction: Mycoplasma pneumoniae is one of the important pathogens of community-acquired pneumonia (CAP), and P1 adhesin serves as a pathogenic protein and an immune protein involved in the pathogenesis of mycoplasma pneumoniae. The aim of this study was to investigate the P1 adhesin genotype in Mycoplasma pneumoniae and its association with disease severity in patients with CAP from 2017 to 2019.

Methods: M. pneumoniae was identified in patient samples by real-time quantitative polymerase chain reaction (qPCR). The P1 genotypes of samples were determined using a culture-independent P1 typing method.

Results: In total, 1,907 clinical samples were collected from 13 tertiary hospitals in Beijing, Shenyang, and Baotou, including 1488 samples from children and 419 from adults. Of these, 820 samples (43.00%), including 777 from children and 43 from adults, were positive for M. pneumoniae. 797 samples were successfully typed using the culture-independent P1 typing method (P1-1, 605; P1- 2, 192). The M. pneumoniae detection rate and P1-1 detection rate differed significantly between children and adults (both p < 0.01), with P1-1 remaining the dominant genotype. The proportion of P1-2 samples increased in children from 16.75% in 2017 to 28.76% in 2019.

Discussion: No relationship between the P1 genotype and disease severity was identified. Monitoring the genotype changes of P1 adhesin in local populations may positively impact the epidemiological prevention and control of M. pneumoniae infections.

Background: Bloodstream infections (BSIs) caused by Acinetobacter baumannii have been associated with high mortality. To improve the outcomes of patients, this study explored the clinical characteristics and outcomes of patients with BSIs, as well as the phenotypic and genomic characteristics of these isolates.

Methods: A retrospective cohort study was conducted involving A. baumannii BSIs cases from 2020 to 2023 in a tertiary hospital. The clinical characteristics of all A. baumannii isolates were evaluated. Virulence phenotypes of all isolates were evaluated using the growth curve, biofilm-forming assay, antiserum complement killing, and G.mellonella killing assay. Furthermore, whole-genome sequencing (WGS) was utilized to analyze genomic characteristics.

Results: The 30-day mortality rate of 67 patients with BSIs was 55.22%. Patients in the death group had significantly lower platelet counts and higher CRP levels than those in the survival group. Additionally, higher rates of antibiotic use (≥2 classes) and greater carbapenem exposure were observed. Among the isolates, CRAb accounted for 80.6%, ST2 accounted for 76.12%, and KL2/3/7/77/160 accounted for 65.67%. The predominant KL type was KL3, found in 19.4% of the isolates. All ST2 and KL2/3/7/77/160 isolates were CRAb. Among the isolates, 90.7% of the CRAb isolates coharbored bla_OXA-23 and bla_OXA-66 , while one coharbored bla_NDM-1 and bla_OXA-23 . Compared with non-ST2 and non KL2/3/7/77/160 infections, ST2 and KL2/3/7/77/160 infections had higher mortality rates (66.0% vs. 23.5%, P=0.002; 65.90% vs. 34.78%, P=0.015). Patients with ST2 and KL2/3/7/77/160 infections underwent more invasive procedures, received two or more antibiotics and carbapenem therapy before isolation, and had lower serum albumin levels. These isolates exhibited significantly higher resistance to antimicrobial agents. No significant differences in virulence phenotypes were observed between the two groups, except for biofilm formation between the ST2 and non-ST2 groups (P=0.002). However, these isolates harbored more virulence genes related to iron uptake and biofilm formation.

Conclusion: The mortality rate associated with BSIs caused by A. baumannii is high. It is of great significance for clinicians to pay attention to the risk factors of the clinical characteristics of patients and to identify the ST and KL types of the strains causing the infection at an early stage.

Background: Listeria (L.) monocytogenes is primarily transmitted via contaminated food and can cause listeriosis, an infection often associated with sepsis and meningitis in at-risk individuals. Accurate outbreak detection relies on whole genome sequencing (WGS) and core genome multilocus sequence typing (cgMLST), which use allele thresholds to identify related strains.

Methods: This study investigated mutation rates in L. monocytogenes, focusing on isolates with DNA repair deficiencies. Serial subcultivations were performed, comparing a repair-deficient isolate with a wild-type control. Genetic variability was assessed using WGS and cgMLST.

Results: Mutation rates were significantly higher in repair-deficient isolates, exceeding typical cgMLST thresholds currently used in Listeria outbreak investigations, leading to a misclassification of related isolates as unrelated. An additional analysis of the Austrian Listeria database revealed that such deficiencies are rare among isolates.

Conclusions: The standard 7-allele cgMLST threshold effectively identifies related strains in most cases, but may require adjustments for hypermutator strains. Incorporating DNA repair data could improve the accuracy of outbreak investigations, ensuring reliable public health responses.

The vaginal microbiome of healthy women is dominated by Lactobacillus spp. A variety of illnesses, such as vaginosis, sexually transmitted infections (STIs), failed implantation, premature birth (PTB), and preterm pre-labor membrane rupture, are brought on by an unbalanced microbiota. Pregnancy is associated with a decrease in the metabolic capacity of the vaginal resident microbiome, which is consistent with a change to a less complex Lactobacillus-dominated microbiome. Age, race, sexual intercourse, smoking, IUD, contraception, lifestyle, and diet all affect the makeup of the vaginal microbiome. Moreover, physiological events including menarche, the menstrual cycle, pregnancy, menopause, and other hormonal changes have an impact on the vaginal microbiome. The vaginal microbiome is significantly disrupted by the menstrual cycle, with significant changes toward a more varied microbiota occurring around menstruation. Several major factors maintain or disrupt the vaginal microbiome including ethnic group, menstruation cycle, and pregnancy which are discussed in this section. In the index pregnancy, the vaginal microbiota of women who had already given birth, or had just experienced an induced or spontaneous abortion, was qualitatively and quantitatively different from that of women who were having their first child. Early pregnancy vaginal microbiome depletion is a risk factor for early pregnancy miscarriage. Although, early pregnancy miscarriage is not always caused by a high bacterial diversity and quantity of lactobacilli. Lactobacillus protects against pathogens through the production of antibacterial compounds such as lactic acid and bacteriocins.

About 71% of healthcare-associated infections are due to antibiotic-resistant bacteria, such as carbapenem-resistant A. baumannii, classified by World Health Organization into a critical priority group of pathogens. The antimicrobial resistance profile of A. baumannii relies on its ability to produce several virulence factors, including biofilm formation. Its ability to adhere and persist on surfaces as biofilm has contributed to its pathogenicity and drug resistance. In this study, the ability of an antimicrobial peptide (a chionodracine-derived peptide named KHS-Cnd) to inhibit or reduce biofilm formation was investigated as an example of a potential strategy to counteract infections caused by biofilm-forming pathogens. To this aim, the antimicrobial profiles were first analyzed in selected A. baumannii strains, two reference and six clinical strains, all biofilm-forming with different capability, regardless of whether they are drug resistant or sensitive. Successively, we investigated the bactericidal activity of the peptide that showed MIC values ranging from 5 to 10 µM and a significative antibiofilm activity on all tested strains at sub-inhibitory concentrations. In fact, KHS-Cnd can hinder biofilm A. baumannii strains formation with an inhibition percentage ranging between 65% and 10%. Also a statistically significant reduction of mature biofilm ranging from 20% to 50% was observed in four out of eight tested A. baumannii strains. KHS-Cnd impacts various stages of biofilm formation, including the inhibition of surface-associated and twitching motilities depending on the different strain. In particular, our results showed that only two strains possessed surface-associated motility that was strongly impaired by KHS-Cnd treatment; three clinical strains, instead, showed twitching motility, whose inhibition for two of them was evident after 24 h of incubation with peptide. Moreover, the invasion of pulmonary cells by A. baumannii was significantly impaired with a reduction of about 32% after treatment with 1.25 µM KHS-Cnd. Finally, when the peptide was used together with ceftazidime/avibactam against resistant A. baumannii strains, it was able to reduce the minimal inhibitory concentration of antibiotics needed to inhibit the microorganism growth.

This study aimed to investigate the relationship between gut microbiota composition, fecal metabolites, and postoperative prognosis in patients with extrahepatic cholangiocarcinoma (eCCA). A total of 53 patients with resectable eCCA and 21 healthy volunteers as a control group were included. 16S rRNA gene sequencing and metabolomic analyses revealed significant differences in the gut microbial community structure and altered fecal metabolites profiles between eCCA patients and healthy controls. Univariate and multivariate Cox regression analyses indicated that factors such as preoperative total bilirubin, indirect bilirubin, and specific metabolites were closely associated with overall survival in patients with eCCA post-surgery. The constructed nomogram model further demonstrated the predictive value of these factors, achieving a C-index of 0.718, with calibration curves confirming its strong predictive performance. In conclusion, gut microbiota composition and fecal metabolites play a crucial role in the surgical prognosis of eCCA patients, providing new insights for clinical prognostic assessment.