Microorganisms最新文献

Background: Patients in critical care units (CCUs) are at an increased risk of bloodstream infections (BSIs), which can be associated with central vascular catheters (CVCs). This study describes BSIs, CVC-BSIs, organism distribution, percentage of antimicrobial resistant (AMR) organisms, and case fatality rates (CFRs) over the first six years of a voluntary national CCU surveillance programme in England.

Methods: Surveillance data on BSIs, CVCs, and bed-days between 04/2017 and 03/2023 for adult CCUs were linked to mortality and AMR data, and crude rates were calculated.

Results: The rates of CCU-BSIs and CCU-CVC-BSIs were stable for the first three years (3.6 and 1.7 per 1000 bed-days in 2019/20), before increasing by 75% and 94% in 2020/21, respectively, and returning to near pre-pandemic levels by 2022/23. Gram-negative bacteria accounted for 50.3% of all CCU-BSIs, followed by Gram-positive bacteria (39.6%) and Candida spp. (8.6%). Klebsiella spp. saw increases in percentage AMR, whereas other organisms saw declines or similar levels. The overall CFR was 30.2%.

Conclusions: BSI incidence in CCUs remained stable across the study period, except for an increase in 2020/21 which reverted by 2022/23. These data provide a benchmark for CCUs and give insight into long-term AMR patterns where comparable national data are limited.

KPC is a clinically significant serine carbapenemase in most countries, and its rapid spread threatens global public health. bla_KPC transmission is commonly mediated by Tn4401 transposons. The bla_KPC gene has also been found in non-Tn4401 elements (NTE_KPC). To fill the gap in the understanding of the stability and dissemination of NTE_KPC-carrying plasmids, we selected and characterized carbapenem-resistant bacteria isolated between 2009 and 2016 from a hospital for a retrospective study of their plasmids conjugation capacity, impact on fitness, and replication in different species. Different clones were selected using PFGE, and their genomes were sequenced using Illumina and Oxford Nanopore methods. Minimum inhibitory concentrations (MICs) were determined by broth microdilution. Plasmid copy numbers (PCNs) were determined using qPCR. Doubling time was used to analyze fitness change. Most isolates (67%, 33/49) carried bla_KPC, of which 85% presented bla_KPC in a NTE_KPC. The 25 isolates selected presented the bla_KPC gene in NTE_KPC-IId in IncQ1-type plasmids, showing multispecies dissemination. IncQ1 plasmids were mobilizable and PCN seemed to be directly linked to the species, presenting a high-copy number, mainly in K. pneumoniae. No relationship was observed between IncQ1 PCN and carbapenems MIC values. IncQ1 and a conjugative plasmid from K. pneumoniae BHKPC10 were transferred to E. coli J53 without fitness changes, and MIC values were maintained for carbapenems despite the low transconjugant PCN. In addition to IncQ1 with NTE_KPC, Enterobacter cloacae BHKPC28 contained the mcr-9 gene in an IncHI2/IncHI2A conjugative plasmid, which may help the mobility of IncQ1 and the dissemination of two resistance determinants to last-resort antibiotics. Understanding the interaction between plasmids and high-risk lineages can help develop new therapies to prevent the dissemination of resistance traits.

Recently a resurgence of Streptococcus pyogenes infections has arisen, with concerns around the highly virulent M1_UK lineage. Our aim was to characterize S. pyogenes, the immune responses it causes, and to determine the presence of the M1_UK lineage in Sofia, Bulgaria. In our study, the infections were confirmed by culture testing or rapid antigen test. Identification was performed by MALDI-TOF and was followed up by antibiotic susceptibility testing (EUCAST). Virulence factors were identified using multiplex PCR and whole genome sequencing (WGS). Immune responses were measured through detection of serum complement levels, lymphocyte subsets, and cytokine profiling. Out of 82 children, 38 had scarlet fever and the rest had streptococcal pharyngitis. Strains were susceptible to penicillin (β-lactams), macrolides, clindamycin, tetracyclines, co-trimoxazole, fluoroquinolones, and linezolid. Superantigen profiles were identified: SpeA + SpeJ (45%), SpeC, and SpeI + SpeH (27.5% each). A novel Multilocus sequence typing (MLST) haplotype in the mutS gene (d90b) was found in four strains. The M1_UK lineage was detected for the first time in Bulgaria. We observed an increase in complement fractions C3 and C4 and a decrease in T lymphocytes. A significant increase in the levels of IFN-γ, IL-6, and IL-10 with corresponding reduction in IL-17A were revealed. In conclusion, the studied S. pyogenes strains were characterized by their susceptibility to antibiotics and the predominance of SpeA superantigen; for the first time in Bulgaria the presence of M1_UK and a novel SNP variation in the mutS gene (d90b) were found. A mixed pattern of pro- and anti-inflammatory immune responses in patients was observed.

Individual differences in environmental sensitivity are linked to stress-related psychiatric symptoms. In previous research, we found that high environmental sensitivity can be a risk factor for increased inflammation and gut permeability, particularly when gut microbiome diversity is low. However, the specific gut bacterial taxa involved in this interaction remain unclear. As a preliminary study, this research aimed to identify the key gut microbiome taxa associated with this relationship. Environmental sensitivity, gut microbiome composition, gut permeability (lipopolysaccharide-binding protein, LBP), and inflammation (C-reactive protein, CRP) biomarkers were evaluated in 88 participants. The interaction between environmental sensitivity and the relative abundance of the family Marinifilaceae (genus Butyricimonas) was a predictor of CRP levels. Similarly, the interaction between environmental sensitivity and relative abundance of the family Barnesiellaceae (genus Coprobacter), the family Akkermansiaceae (genus Akkermansia), the genus Family XIII AD3011 group, the genus GCA-900066225, or the genus Ruminiclostridium 1 predicted LBP levels. Individuals with high environmental sensitivity exhibited elevated CRP or LBP levels when the relative abundance of these taxa was low. Conversely, highly sensitive individuals had lower CRP or LBP levels when the relative abundance of these taxa was high. This study suggests that specific taxa serve as one of the protective factors against inflammation and gut permeability in individuals with high environmental sensitivity. Further in-depth studies are needed to confirm these associations and understand the underlying mechanisms.

Using a murine osteomyelitis model, we recently demonstrated that Staphylococcus aureus sarA and sarA/agr mutants generated in the USA300 strain LAC are attenuated to a greater extent than an isogenic agr mutant and that this can be attributed to a significant extent to the increased production of extracellular proteases in both mutants. Based on this, we used a mass-based proteomics approach to compare the proteomes of LAC, its isogenic agr, sarA, and sarA/agr mutants, and isogenic derivatives of all four of these strains unable to produce the extracellular proteases aureolysin, SspA, SspB, ScpA, or SplA-F. This allowed us to identify proteins that were present in reduced amounts in sarA, and sarA/agr mutants owing to the increased production of extracellular proteases. A total of 1039 proteins were detected in conditioned media (CM) from overnight cultures of LAC, and protease-mediated degradation was shown to contribute to the reduced abundance of 224 of these (21.6%) in CM from the sarA and sarA/agr mutants. Among these were specific proteins previously implicated in the pathogenesis and therapeutic recalcitrance of S. aureus osteomyelitis. This demonstrates that the ability of sarA to limit protease production plays a key role in post-translational remodeling of the S. aureus proteome to a degree that can be correlated with reduced virulence in our osteomyelitis model, and that it does so irrespective of the functional status of agr. This also suggests that at least some of these 224 proteins may be viable targets for prophylactic or therapeutic intervention.

Pediatric tuberculosis (TB) is still challenged by several diagnostic bottlenecks, imposing a high TB burden in low- and middle-income countries (LMICs). Diagnostic turnaround time (TAT) and ease of operation to suit resource-limited settings are critical aspects that determine early treatment and influence morbidity and mortality. Based on TAT and ease of operation, this article reviews the evolving landscape of TB diagnostics, from traditional methods like microscopy and culture to cutting-edge molecular techniques and biomarker-based approaches. We examined the benefits of efficient rapid results against potential trade-offs in accuracy and clinical utility. The review highlights emerging molecular methods and artificial intelligence-based detection methods, which offer promising improvements in both speed and sensitivity. The review also addresses the challenges of implementing these technologies in resource-limited settings, where most pediatric TB cases occur. Gaps in the existing diagnostic methods, algorithms, and operational costs were also reviewed. Developing optimal diagnostic strategies that balance speed, performance, cost, and feasibility in diverse healthcare settings can provide valuable insights for clinicians, researchers, and policymakers.

Antibiotic resistance is on the WHO's top 10 list of global public health threats due to its rapid emergence and spread but also because of the high morbidity and mortality associated with it. Amongst the main species driving this phenomenon is A. baumannii, a member of the ESKAPE group of medical assistance-associated infections causing species famous for its extensively drug-resistant phenotypes. Our findings note a 91.52% frequency of extensively drug-resistant carbapenem-resistant A. baumannii (XDR CRAB) phenotype amongst clinical isolates from multiple hospitals in two major cities from northwestern and central Romania, harboring multiple antibiotic resistance genes such as bla_OXA-23-like in 108 (91.5%) isolates, bla_{OXA-24/40-like} in 88 (74.6%) isolates, bla_NDM in 29 (25%) isolates, ArmA in 75 (63.6%) isolates, and ant(3″)-I in 69 (58.5%) isolates and sul1 in 113 (95.76%) isolates. The isolates, although nearly identical in phenotype, displayed different genotypical profiles, with varying degrees of similarity across hospitals and cities, raising the possibility of both local outbreaks of a single clone and widespread dissemination of resistant isolates.

Bioactive compounds and organic acids are applied to a wide range of foods against different types of foodborne pathogens. In the present study, carvacrol and thymol (1000 mg/L) were applied in wine-based marinades, alone or in combination with them and in combination with tartaric acid, malic acid, ascorbic acid, citric acid, and acetic acid (in concentration 0.1% w/v), in chicken and beef fillets and their antimicrobial activity, antioxidant capacity, and pH were estimated during refrigerated storage. Likewise, their antimicrobial activity was recorded against Enterobacteriaceae, total mesophilic bacteria, yeasts/molds, and lactic acid bacteria. The outcome demonstrated that both meats kept under similar storage conditions (4 °C/9 days) exhibited lower microbial growth, particularly with Enterobacteriaceae, when treated with wine-based carvacrol-thymol marinades and may extend their shelf-life. This antimicrobial action was more pronounced in the beef samples. The total phenolic content (TPC) and the antioxidant activity of the applied marinades were determined using the Folin-Ciocalteau method and ABTS and DPPH radical scavenging activity methods, respectively. The results revealed that marinades with thymol and/or carvacrol in combination with acetic or ascorbic acid had greater TPC and antioxidant activity. The pH values of the respective marinades applied to both chicken and beef fillets exhibited an upturn during storage. Consequently, these marinades, even at low concentrations, could be used as natural preservatives in meat products.

The medicinal potential of plant extracts, especially their antimicrobial, antioxidant, antiviral and cytotoxic properties, has gained significant attention in recent years. This study examined the in vitro bioactivities of several selected Greek medicinal plants, like Eucalyptus globulus L., Thymus vulgaris L., Salvia rosmarinus L. and Ocimum basilicum L., are well-known for their traditional therapeutic use. Minimum inhibitory concentration (MIC) assays were used to evaluate the antimicrobial activity of the extracts against pathogenic bacteria. The antioxidant activity was carried out using the DPPH method, while the cytotoxicity of the plants was determined using the Alamar Blue method. In addition, the antiviral efficacy of the samples was tested against DENV in different cell lines. The majority of medicinal herbs demonstrated significant antimicrobial action (MIC = 30-3000 μg∙mL^-1). The extracts showed great antioxidant activity, while the Salvia rosmarinus L. extract turned out to be the most effective (IC₅₀ = 12.89 ± 0.11 μg∙mL^-1). In contrast, the extract of Eucalyptus globulus L. had the lowest antioxidant action (IC₅₀ = 71.02 ± 0.42 μg∙mL^-1). The results of the Alamar Blue method were presented with CC₅₀ values, and it was shown that Eucalyptus globulus L. extract exhibited the highest cytotoxicity (CC₅₀ = 5.94% v/v ± 0.04). Similarly, the results of the antiviral potential of extracts were expressed as EC₅₀ values, and Eucalyptus globulus L. was characterized as the most effective sample against dengue virus infection, with EC₅₀ values estimated at 2.37% v/v ± 0.6 (HuhD-2 cells infected with DENV-2) and 0.36% v/v ± 0.004 (Huh7.5 cells infected with DVR2A). These findings provide a foundation for further studies in order to combat infectious diseases and promote human health.

Irritable bowel syndrome (IBS) is a chronic disorder of the gastrointestinal tract. Its pathogenesis involves multiple factors, including visceral hypersensitivity and immune activation. NLRP3 inflammasome is part of the nucleotide-binding oligomerization domain-like receptor (NLR) family, a crucial component of the innate immune system. Preclinical studies have demonstrated that inhibiting NLRP3 reduces visceral sensitivity and IBS symptoms, like abdominal pain, and diarrhea, suggesting that targeting the NLRP3 might represent a novel therapeutic approach for IBS. This review aims to assess the NLRP3 inhibitors (tranilast, β-hydroxybutyrate, Chang-Kang-fang, paeoniflorin, coptisine, BAY 11-7082, and Bifidobacterium longum), highlighting the signaling pathways, and their potential role in IBS symptoms management was assessed. Although premature, knowledge of the action of synthetic small molecules, phytochemicals, organic compounds, and probiotics might make NLRP3 a new therapeutic target in the quiver of physicians' therapeutic choices for IBS symptoms management.