bacterial challenge
Dotaz
Zobrazit nápovědu
BACKGROUND CONTEXT: Spondylodiscitis management presents significant clinical challenges, particularly in critically ill patients, where the risks and benefits of surgical intervention must be carefully balanced. The optimal timing of surgery in this context remains a subject of debate. PURPOSE: This study aims to evaluate the effectiveness of early surgery versus delayed surgery or conservative management in critically ill patients with de novo pyogenic spondylodiscitis. STUDY DESIGN/SETTING: This is an international, multicenter retrospective cohort study involving 24 centers, primarily in Europe. PATIENT SAMPLE: The study included 192 critically ill patients (65.63% male) with a median age of 69 years, all severely affected by pyogenic spondylodiscitis characterized by an initial CRP level >200 mg/l or the presence of two out of four Systemic Inflammatory Response Syndrome criteria upon admission. OUTCOME MEASURES: The primary outcome was 30-day mortality. Secondary outcomes included length of ICU stay, length of hospital stay, and relapse rates of spondylodiscitis. METHODS: Patients were divided into three groups: early surgery (within three days of admission), delayed surgery (after three days of admission), and conservative therapy. Propensity score matching and multivariate regression analyses were performed to adjust for baseline differences and assess the impact of treatment modalities on mortality and other clinical outcomes. RESULTS: Delayed surgery was associated with significantly lower 30-day mortality (4.05%) compared to early surgery (27.85%) and conservative therapy (27.78%) (p<.001). Delayed surgery also resulted in shorter hospital stays (42.76 days) compared to conservative therapy (55.53 days) and early surgery (26.33 days) (p<.001), and shorter ICU stays (4.52 days) compared to conservative therapy (16.48 days) and early surgery (7.92 days) (p<.001). The optimal window for surgery, minimizing mortality, was identified as ten to fourteen days postadmission (p=.02). Risk factors for increased mortality included age (p<.05), multiple organ failure (p<.05), and vertebral body destruction (p<.05), whereas delayed surgery (p<.05) and the presence of an epidural abscess were associated with reduced mortality (p<.05). CONCLUSIONS: Delayed surgery, optimally between 10 to 14 days postadmission, was associated with lower mortality in critically ill spondylodiscitis patients. These findings highlight the potential benefits of considering surgical timing to improve patient outcomes.
- MeSH
- antibakteriální látky terapeutické užití MeSH
- délka pobytu MeSH
- discitida * terapie mortalita chirurgie mikrobiologie MeSH
- konzervativní terapie MeSH
- kritický stav MeSH
- lidé středního věku MeSH
- lidé MeSH
- retrospektivní studie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- výsledek terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
Cyanobacteria are prokaryotic organisms characterised by their complex structures and a wide range of pigments. With their ability to fix CO2, cyanobacteria are interesting for white biotechnology as cell factories to produce various high-value metabolites such as polyhydroxyalkanoates, pigments, or proteins. White biotechnology is the industrial production and processing of chemicals, materials, and energy using microorganisms. It is known that exposing cyanobacteria to low levels of stressors can induce the production of secondary metabolites. Understanding of this phenomenon, known as hormesis, can involve the strategic application of controlled stressors to enhance the production of specific metabolites. Consequently, precise measurement of cyanobacterial viability becomes crucial for process control. However, there is no established reliable and quick viability assay protocol for cyanobacteria since the task is challenging due to strong interferences of autofluorescence signals of intercellular pigments and fluorescent viability probes when flow cytometry is used. We performed the screening of selected fluorescent viability probes used frequently in bacteria viability assays. The results of our investigation demonstrated the efficacy and reliability of three widely utilised types of viability probes for the assessment of the viability of Synechocystis strains. The developed technique can be possibly utilised for the evaluation of the importance of polyhydroxyalkanoates for cyanobacterial cultures with respect to selected stressor-repeated freezing and thawing. The results indicated that the presence of polyhydroxyalkanoate granules in cyanobacterial cells could hypothetically contribute to the survival of repeated freezing and thawing.
- MeSH
- fluorescence MeSH
- fluorescenční barviva * metabolismus chemie MeSH
- fyziologický stres * MeSH
- mikrobiální viabilita * MeSH
- polyhydroxyalkanoáty metabolismus MeSH
- průtoková cytometrie * MeSH
- sinice metabolismus fyziologie MeSH
- Synechocystis * metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Acinetobacter baumannii thrives within eukaryotic cells, influencing persistence, treatment approaches, and progression of disease. We probed epithelial cell invasion by A. baumannii and the influence of antibodies raised to outer membrane protein 34 (Omp34) on epithelial interactions. We expressed and purified recombinant Omp34 and induced anti-Omp34 antibodies in Bagg albino or BALB/c mice. Omp34 was evaluated for acute toxicity in mice through histological analysis of six organs. The host cell line, A549, was exposed to both A. baumannii 19606 and a clinical isolate. The study also investigated serum resistance, adherence, internalization, and proliferation of A. baumannii in A549 cells, with and without anti-Omp34 sera, utilizing cell culture techniques and light microscopy. A549 cell viability was evaluated by A. baumannii challenge and exposure to anti-Omp34 sera. Actin disruption experiments using cytochalasin D probed microfilament and microtubule roles in A. baumannii invasion. Omp34 prompted antibody production without toxicity in mice. The serum showed bactericidal effects on both strains. Additionally, both A. baumannii strains were found to form biofilms. Omp34 serum was observed to decrease biofilm formation, bacterial adherence, internalization, and proliferation in A549 cells. Furthermore, the use of anti-Omp34 serum enhanced the post-infection survival of the host cell. Pre-exposure of A549 cells to cytochalasin D reduced bacterial internalization, highlighting the role of actin polymerization in the invasion process. Microscopic analysis revealed various interactions, such as adherence, membrane alterations, vacuolization, apoptosis, and cellular damage. Anti-Omp34 serum-exposed A549 cells were protected and showed reduced damage. The findings reveal that A. baumannii can significantly multiply intracellularly within host cells. This suggests the bacterium's ability to establish an environment conducive to its replication by preventing fusion with degradative lysosomes and inhibiting acidification. This finding contributes to the understanding of A. baumannii's intracellular persistence and highlights the role of Omp34 in influencing apoptosis, autophagy, and bacterial adherence, which may impact the development of effective treatments against A. baumannii infections.
- MeSH
- Acinetobacter baumannii * fyziologie imunologie patogenita MeSH
- bakteriální adheze * MeSH
- biofilmy růst a vývoj MeSH
- buňky A549 MeSH
- epitelové buňky mikrobiologie MeSH
- infekce bakteriemi rodu Acinetobacter * mikrobiologie imunologie MeSH
- lidé MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- protilátky bakteriální * imunologie MeSH
- viabilita buněk MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The spread of multidrug-resistant Escherichia coli in healthcare facilities is a global challenge. Hospital-acquired infections produced by Escherichia coli include gastrointestinal, blood-borne, urinary tract, surgical sites, and neonatal infections. Therefore, novel approaches are needed to deal with this pathogen and its rising resistance. The concept of attenuating virulence factors is an alternative strategy that might lead to low levels of resistance and combat this pathogen. A sub-inhibitory concentration (1⁄4 MIC) of sitagliptin and nitazoxanide was used for phenotypic assessments of Escherichia coli virulence factors such as biofilm production, swimming motility, serum resistance, and protease production. Moreover, qRT-PCR was used to determine the impact of sub-MIC of the tested drugs on the relative expression levels of papC, fimH, fliC, kpsMTII, ompT_m, and stcE genes encoding virulence factors in Escherichia coli. Also, an in vivo model was conducted as a confirmatory test. Phenotypically, our findings demonstrated that the tested strains showed a significant decrease in all the tested virulence factors. Moreover, the genotypic results showed a significant downregulation in the relative expression levels of all the tested genes. Besides, the examined drugs were found to be effective in protecting mice against Escherichia coli pathogenesis. Sitagliptin and nitazoxanide exhibited strong anti-virulence activities against Escherichia coli. In addition, it is recommended that they might function as adjuvant in the management of Escherichia coli infections with either conventional antimicrobial agents or alone as alternative treatment measures.
- MeSH
- antibakteriální látky * farmakologie MeSH
- biofilmy účinky léků MeSH
- dusíkaté sloučeniny MeSH
- Escherichia coli * účinky léků patogenita genetika MeSH
- faktory virulence genetika metabolismus MeSH
- infekce vyvolané Escherichia coli * farmakoterapie mikrobiologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mnohočetná bakteriální léková rezistence MeSH
- myši MeSH
- proteiny z Escherichia coli genetika MeSH
- sitagliptin fosfát * farmakologie MeSH
- thiazoly * farmakologie MeSH
- virulence účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Escherichia coli is a significant pathogen in extraintestinal infections, and ESBL-producing E. coli poses a major clinical challenge due to its antibiotic resistance. This study comprehensively analyzed E. coli isolates from urine and blood samples of patients with urinary tract and bloodstream infections at three major tertiary hospitals in South Korea. The goal was to provide insights into the distribution, antibiotic resistance, and virulence factors of these strains. Our analysis identified CTX-M and TEM as the dominant ESBL types, found in 71.7% and 61.7% of isolates, respectively, with 46.7% showing co-occurrence. Multilocus sequence typing (MLST) revealed the predominance of high-risk clones such as ST131, ST69, ST73, and ST95, with rare sequence types like ST410 and ST405 also identified. The high prevalence of virulence factors, including iutA (80.8%) and kpsMII (74.2%), further highlights the complexity of these strains. In addition, 38.3% of clinical isolates contained a combination of siderophore, adhesin, protectin, and toxin-related genes. There was no significant difference between urinary tract and bloodstream infections or regional differentiation in Korea. This study highlights the importance of controlling ESBL-producing E. coli infections, especially given the increasing incidence among patients with underlying medical conditions and older adults who are more susceptible to urinary tract infections. These findings serve as valuable indicators for pathogen analysis, especially those harboring antibiotic resistance and toxin genes. The insights gained are expected to contribute significantly to the development of infectious disease prevention and control strategies.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriemie * mikrobiologie epidemiologie MeSH
- beta-laktamasy * genetika metabolismus MeSH
- dospělí MeSH
- Escherichia coli * genetika izolace a purifikace patogenita enzymologie účinky léků klasifikace MeSH
- faktory virulence genetika MeSH
- infekce močového ústrojí * mikrobiologie epidemiologie MeSH
- infekce vyvolané Escherichia coli * mikrobiologie epidemiologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mladý dospělý MeSH
- multilokusová sekvenční typizace MeSH
- prevalence MeSH
- proteiny z Escherichia coli genetika metabolismus MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- virulence MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Korejská republika MeSH
The objective of this study was to characterize the virulence characteristics of a collection of Klebsiella pneumoniae isolates collected from different clinical sources. A collection of 60 non-repetitive K. pneumoniae isolates, was studied. In vitro, virulence was analyzed by testing the survival of bacteria in pooled human serum. Isolates were typed by MLST. The genomes of 23 K. pneumoniae isolates, representatives of different STs and virulence profiles, were completely sequenced using the Illumina platform. Of note, 26/60 of K. pneumoniae isolates were resistant to killing by complement. Serum-resistant isolates belonged to distinct STs. Analysis of WGS data with VFDB showed the presence of several virulence genes related various virulence functions. Specifically, serum-resistant isolates carried a higher number of ORFs, which were associated with serum resistance, compared to serum-sensitive isolates. Additionally, analysis of WGS data showed the presence of multiple plasmid replicons that could be involved with the spread and acquisition of resistance and virulence genes. In conclusion, analysis of virulence characteristics showed that an important percentage (31.6%) of K. pneumoniae isolates were in vitro virulent by exhibiting resistance to serum. Thus, the presence of several virulence factors, in combination with the presence of multidrug resistance, could challenge antimicrobial therapy of infections caused by such bacteria.
- MeSH
- faktory virulence * genetika MeSH
- genom bakteriální MeSH
- infekce bakteriemi rodu Klebsiella * mikrobiologie genetika MeSH
- Klebsiella pneumoniae * genetika patogenita izolace a purifikace MeSH
- lidé MeSH
- multilokusová sekvenční typizace MeSH
- nemocnice MeSH
- plazmidy genetika MeSH
- sekvenování celého genomu MeSH
- virulence genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Řecko MeSH
Bacterial proton pumps, proteorhodopsins (PRs), are a major group of light-driven membrane proteins found in marine bacteria. They are functionally and structurally distinct from archaeal and eukaryotic proton pumps. To elucidate the proton transfer mechanism by PRs and understand the differences to nonbacterial pumps on a molecular level, high-resolution structures of PRs' functional states are needed. In this work, we have determined atomic-resolution structures of MAR, a PR from marine actinobacteria, in various functional states, notably the challenging late O intermediate state. These data and information from recent atomic-resolution structures on an archaeal outward proton pump bacteriorhodopsin and bacterial inward proton pump xenorhodopsin allow for deducing key universal elements for light-driven proton pumping. First, long hydrogen-bonded chains characterize proton pathways. Second, short hydrogen bonds allow proton storage and inhibit their backflow. Last, the retinal Schiff base is the active proton donor and acceptor to and from hydrogen-bonded chains.
Klebsiella pneumoniae, a Gram-negative bacterium, comprises strains with diverse virulence potentials, ranging from classical to hypervirulent variants. Understanding the genetic basis underlying the virulence disparities between hypervirulent (hvKp) and classical K. pneumoniae (cKp) strains is crucial. hvKp strains are characterized by hypermucoviscosity, attributed to the presence of specific virulence genes and the production of molecules that aid in their ability to survive, evade host immune defenses, and cause infection. In contrast, classical strains exhibit a broader array of antimicrobial resistance determinants, conferring resistance to multiple antibiotics. Although current definitions of hvKp incorporate clinical features, phenotypes, and genotypes, identifying hvKp strains in clinical settings remains challenging. Genomic studies have been pivotal and have helped to identify distinct genetic profiles in hvKp strains, including unique virulence plasmids and chromosomal variations, underscoring the genetic diversity within K. pneumoniae populations. This review examines the virulence and genetic determinants associated with hvKp. The presence of genes defining hypervirulence, alongside considerations of their utility as biomarkers and targets for therapeutic strategies, is discussed, while also providing insight into biofilm formation by hvKp and key questions that need urgent responses in understanding hvKp.
- MeSH
- antibakteriální látky farmakologie MeSH
- biofilmy růst a vývoj MeSH
- faktory virulence * genetika MeSH
- infekce bakteriemi rodu Klebsiella * mikrobiologie MeSH
- Klebsiella pneumoniae * patogenita genetika účinky léků MeSH
- lidé MeSH
- virulence genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Trained immunity is defined as an enhanced state of the innate system which leads to an improved immune response against related or non-related pathogens. Bacillus Calmette-Guérin (BCG) vaccine, a live attenuated Mycobacterium bovis strain, is currently one of the main inductors of trained immunity. The objective of the present study was to evaluate the protective effects of heat-inactivated M. bovis (HIMB) against Plasmodium berghei and Borrelia burgdorferi and characterize the immunological mechanisms involved. BALB/c and C3H/HeN mice were randomly assigned in similar number to either immunized group receiving two oral doses of HIMB with a 4-week interval, or control group treated with PBS. All the BALB/c mice were intraperitoneally infected with P. berghei while the C3H/HeN mice were subcutaneously infected with B. burgdorferi. Pathogen burden was significantly reduced in both immunized groups when compared to controls. The number of macrophages significantly decreased in the liver or in the spleen of the mice that had been immunized prior to the challenge with P. berghei or B. burgdorferi, respectively. Furthermore, the immunized groups showed an apparent upregulation of IFN-γ, TNF-α and IL-1α in the liver (P. berghei challenge) or a significant increase in IL-1α producing cells in the spleen (B. burgdorferi challenge). Our findings suggest that oral immunization with heat-inactivated mycobacteria limits pathogen burden through stimulation of the innate immune response in two vector-borne diseases in mice.
- MeSH
- adjuvancia imunologická * aplikace a dávkování MeSH
- BCG vakcína * imunologie aplikace a dávkování MeSH
- Borrelia burgdorferi imunologie MeSH
- cytokiny MeSH
- inaktivované vakcíny imunologie aplikace a dávkování MeSH
- interferon gama imunologie MeSH
- interleukin-1alfa imunologie MeSH
- játra imunologie MeSH
- lymeská nemoc * prevence a kontrola imunologie MeSH
- makrofágy imunologie MeSH
- malárie * prevence a kontrola imunologie MeSH
- Mycobacterium bovis * imunologie MeSH
- myši inbrední BALB C MeSH
- myši inbrední C3H MeSH
- myši MeSH
- Plasmodium berghei imunologie MeSH
- protilátky bakteriální krev MeSH
- slezina imunologie mikrobiologie MeSH
- TNF-alfa imunologie MeSH
- vysoká teplota MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Data from surveillance on antibiotic resistance have shown an increasing prevalence of non-enzymatic resistance (β-lactamase-negative ampicillin-resistant) to β-lactam antibiotics among H. influenzae strains in the Czech Republic. Aminopenicillins are recommended agents for non-invasive Haemophilus influenzae infections. The phenomenon of non-enzymatic resistance to β-lactams is complicated by the fact that the phenotypic detection of PBP3 with specific amino acid substitutions (rPBP3) is challenging, since rPBP3 isolates have repeatedly been demonstrated to be split by the epidemiological cut-off values (ECOFF) for aminopenicillins defined by EUCAST. OBJECTIVES: We sought to determine whether the penicillin disc has sufficient detection ability to predict the non-enzymatic mechanism; whether other antibiotics can be used for detection; and what is the agreement between the broth microdilution and disc diffusion methods. METHODS: We undertook susceptibility testing of selected antibiotics according to EUCAST of 153 rPBP3 strains, and sequencing of the ftsI gene to determination amino acid substitutions. RESULTS: For a selected set of rPBP strains: (i) the detection capability for penicillin, ampicillin, cefuroxime and amoxicillin/clavulanate was found to be 91.5%, 94.4%, 89.5% and 70.6%, respectively; (ii) the categorical agreement between the disc diffusion method and the MIC for ampicillin and cefuroxime was 71.1% and 83.8%, respectively. CONCLUSIONS: We observed better recognition of rPBP3 strains by the ampicillin disc than by the penicillin disc. There is frequently a discrepancy in the interpretation of susceptibility results between the methods used.
- MeSH
- antibakteriální látky * farmakologie MeSH
- bakteriální proteiny * genetika MeSH
- beta-laktamová rezistence * MeSH
- beta-laktamy * farmakologie MeSH
- fenotyp MeSH
- Haemophilus influenzae * účinky léků genetika izolace a purifikace enzymologie MeSH
- hemofilové infekce mikrobiologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti metody MeSH
- proteiny vázající penicilin * genetika MeSH
- sekvenční analýza DNA MeSH
- substituce aminokyselin * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
