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1.
Vet Res ; 55(1): 59, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38715095

RESUMO

Klebsiella pneumoniae has become one of the most intractable gram-negative pathogens infecting humans and animals due to its severe antibiotic resistance. Bacteriophages and protein products derived from them are receiving increasing amounts of attention as potential alternatives to antibiotics. In this study, we isolated and investigated the characteristics of a new lytic phage, P1011, which lyses K5 K. pneumoniae specifically among 26 serotypes. The K5-specific capsular polysaccharide-degrading depolymerase dep1011 was identified and expressed. By establishing murine infection models using bovine strain B16 (capable of supporting phage proliferation) and human strain KP181 (incapable of sustaining phage expansion), we explored the safety and efficacy of phage and dep1011 treatments against K5 K. pneumoniae. Phage P1011 resulted in a 60% survival rate of the mice challenged with K. pneumoniae supporting phage multiplication, concurrently lowering the bacterial burden in their blood, liver, and lungs. Unexpectedly, even when confronted with bacteria impervious to phage multiplication, phage therapy markedly decreased the number of viable organisms. The protective efficacy of the depolymerase was significantly better than that of the phage. The depolymerase achieved 100% survival in both treatment groups regardless of phage propagation compatibility. These findings indicated that P1011 and dep1011 might be used as potential antibacterial agents to control K5 K. pneumoniae infection.


Assuntos
Bacteriófagos , Infecções por Klebsiella , Klebsiella pneumoniae , Animais , Klebsiella pneumoniae/virologia , Klebsiella pneumoniae/fisiologia , Camundongos , Infecções por Klebsiella/terapia , Infecções por Klebsiella/veterinária , Infecções por Klebsiella/microbiologia , Bacteriófagos/fisiologia , Modelos Animais de Doenças , Terapia por Fagos , Feminino , Glicosídeo Hidrolases/metabolismo , Bovinos
2.
PLoS Pathog ; 20(5): e1012187, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38718038

RESUMO

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) has significant challenges to human health and clinical treatment, with KPC-2-producing CRKP being the predominant epidemic strain. Therefore, there is an urgent need to identify new therapeutic targets and strategies. Non-coding small RNA (sRNA) is a post-transcriptional regulator of genes involved in important biological processes in bacteria and represents an emerging therapeutic strategy for antibiotic-resistant bacteria. In this study, we analyzed the transcription profile of KPC-2-producing CRKP using RNA-seq. Of the 4693 known genes detected, the expression of 307 genes was significantly different from that of carbapenem-sensitive Klebsiella pneumoniae (CSKP), including 133 up-regulated and 174 down-regulated genes. Both the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and Gene Ontology (GO) analysis showed that these differentially expressed genes (DEGs) were mainly related to metabolism. In addition, we identified the sRNA expression profile of KPC-2-producing CRKP for the first time and detected 115 sRNAs, including 112 newly discovered sRNAs. Compared to CSKP, 43 sRNAs were differentially expressed in KPC-2-producing CRKP, including 39 up-regulated and 4 down-regulated sRNAs. We chose sRNA51, the most significantly differentially expressed sRNA in KPC-2-producing CRKP, as our research subject. By constructing sRNA51-overexpressing KPC-2-producing CRKP strains, we found that sRNA51 overexpression down-regulated the expression of acrA and alleviated resistance to meropenem and ertapenem in KPC-2-producing CRKP, while overexpression of acrA in sRNA51-overexpressing strains restored the reduction of resistance. Therefore, we speculated that sRNA51 could affect the resistance of KPC-2-producing CRKP by inhibiting acrA expression and affecting the formation of efflux pumps. This provides a new approach for developing antibiotic adjuvants to restore the sensitivity of CRKP.


Assuntos
Carbapenêmicos , Klebsiella pneumoniae , beta-Lactamases , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Klebsiella pneumoniae/efeitos dos fármacos , beta-Lactamases/genética , beta-Lactamases/metabolismo , Carbapenêmicos/farmacologia , Humanos , Regulação Bacteriana da Expressão Gênica , Antibacterianos/farmacologia , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Pequeno RNA não Traduzido/genética , RNA Bacteriano/genética , Testes de Sensibilidade Microbiana
3.
Molecules ; 29(9)2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38731399

RESUMO

The antibacterial effects of a selection of volatile fatty acids (acetic, propionic, butyric, valeric, and caproic acids) relevant to anaerobic digestion were investigated at 1, 2 and 4 g/L. The antibacterial effects were characterised by the dynamics of Enterococcus faecalis NCTC 00775, Escherichia coli JCM 1649 and Klebsiella pneumoniae A17. Mesophilic anaerobic incubation to determine the minimum bactericidal concentration (MBC) and median lethal concentration of the VFAs was carried out in Luria Bertani broth at 37 °C for 48 h. Samples collected at times 0, 3, 6, 24 and 48 h were used to monitor bacterial kinetics and pH. VFAs at 4 g/L demonstrated the highest bactericidal effect (p < 0.05), while 1 g/L supported bacterial growth. The VFA cocktail was the most effective, while propionic acid was the least effective. Enterococcus faecalis NCTC 00775 was the most resistant strain with the VFAs MBC of 4 g/L, while Klebsiella pneumoniae A17 was the least resistant with the VFAs MBC of 2 g/L. Allowing a 48 h incubation period led to more log decline in the bacterial numbers compared to earlier times. The VFA cocktail, valeric, and caproic acids at 4 g/L achieved elimination of the three bacteria strains, with over 7 log10 decrease within 48 h.


Assuntos
Antibacterianos , Enterococcus faecalis , Ácidos Graxos Voláteis , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Ácidos Graxos Voláteis/metabolismo , Ácidos Graxos Voláteis/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/crescimento & desenvolvimento , Anaerobiose , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Propionatos/farmacologia , Concentração de Íons de Hidrogênio , Ácidos Pentanoicos/farmacologia
4.
Molecules ; 29(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38731545

RESUMO

Functional Lyocell fibers gain interest in garments and technical textiles, especially when equipped with inherently bioactive features. In this study, Lyocell fibers are modified with an ion exchange resin and subsequently loaded with copper (Cu) ions. The modified Lyocell process enables high amounts of the resin additive (>10%) through intensive dispersion and subsequently, high uptake of 2.7% Cu throughout the whole cross-section of the fiber. Fixation by Na2CO3 increases the washing and dyeing resistance considerably. Cu content after dyeing compared to the original fiber value amounts to approx. 65% for reactive, 75% for direct, and 77% for HT dyeing, respectively. Even after 50 household washes, a recovery of 43% for reactive, 47% for direct and 26% for HT dyeing is proved. XRD measurements reveal ionic bonding of Cu fixation inside the cellulose/ion exchange resin composite. A combination of the fixation process with a change in Cu valence state by glucose/NaOH leads to the formation of Cu2O crystallites, which is proved by XRD. Cu fiber shows a strong antibacterial effect against Staphylococcus aureus and Klebsiella pneumonia bacteria, even after 50 household washing cycles of both >5 log CFU. In nonwoven blends with a share of only 6% Cu fiber, a strong antimicrobial (CFU > log 5) and full antiviral effectiveness (>log 4) was received even after 50 washing cycles. Time-dependent measurements already show strong antiviral behavior after 30 s. Further, the fibers show an increased die off of the fungal isolate Candida auris with CFU log 4.4, and nonwovens made from 6% Cu fiber share a CFU log of 1.7. Findings of the study predestines the fiber for advanced textile processing and applications in areas with high germ loads.


Assuntos
Antibacterianos , Antifúngicos , Antivirais , Cobre , Antifúngicos/farmacologia , Antifúngicos/química , Antibacterianos/farmacologia , Antibacterianos/química , Antivirais/farmacologia , Antivirais/química , Cobre/química , Cobre/farmacologia , Celulose/química , Celulose/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Têxteis , Testes de Sensibilidade Microbiana , Klebsiella pneumoniae/efeitos dos fármacos , Lignina/química , Lignina/farmacologia , Humanos
5.
J Med Life ; 17(1): 41-49, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38737657

RESUMO

Multi-drug resistant (MDR) Enterobacterales remain a major clinical problem. Infections caused by carbapenem-resistant strains are particularly difficult to treat. This study aimed to assess the clinical and epidemiological characteristics of MDR Enterobacterales isolates. A total of 154 non-repetitive clinical isolates, including Escherichia coli (n = 66), Klebsiella pneumoniae (n = 70), and other Enterobacterales (n = 18), were collected from the Diagnostic Microbiology Laboratory at King Fahad Hospital of the University. Most E. coli isolates were collected from urine specimens (n = 50, 75.8%) and resistance against the third and fourth-generation cephalosporins (ceftriaxone, ceftazidime, cefixime, and cefepime) and fluoroquinolones (ciprofloxacin and levofloxacin) was assessed. Clonal relatedness analysis using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) revealed two clones (E. coli A and B), each comprising two strains. Most K. pneumoniae samples were collected from respiratory specimens (27.1%, 20 samples), and the strains showed overall resistance to most of the antimicrobials tested (54%‒100%). Moreover, clonal-relatedness analysis using ERIC-PCR revealed seven major clones of K. pneumoniae. These findings suggest nosocomial transmission among some identical strains and emphasize the importance of strict compliance with infection prevention and control policies and regulations. Environmental reservoirs could facilitate this indirect transmission, which needs to be investigated.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana Múltipla , Humanos , Farmacorresistência Bacteriana Múltipla/genética , Arábia Saudita/epidemiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Testes de Sensibilidade Microbiana , Masculino , Feminino , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/epidemiologia , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/tratamento farmacológico , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/genética , Infecção Hospitalar/microbiologia , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/tratamento farmacológico , Adulto , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Escherichia coli/genética , Pessoa de Meia-Idade , Hospitais Universitários
6.
J Neuroinflammation ; 21(1): 122, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38720343

RESUMO

Pneumonia is a common comorbidity in patients with severe traumatic brain injury (TBI), and is associated with increased morbidity and mortality. In this study, we established a model of intratracheal Klebsiella pneumoniae administration in young adult male and female mice, at 4 days following an experimental TBI, to investigate how K. pneumoniae infection influences acute post-TBI outcomes. A dose-response curve determined the optimal dose of K. pneumoniae for inoculation (1 x 10^6 colony forming units), and administration at 4 days post-TBI resulted in transient body weight loss and sickness behaviors (hypoactivity and acute dyspnea). K. pneumoniae infection led to an increase in pro-inflammatory cytokines in serum and bronchoalveolar lavage fluid at 24 h post-infection, in both TBI and sham (uninjured) mice. By 7 days, when myeloperoxidase + neutrophil numbers had returned to baseline in all groups, lung histopathology was observed with an increase in airspace size in TBI + K. pneumoniae mice compared to TBI + vehicle mice. In the brain, increased neuroinflammatory gene expression was observed acutely in response to TBI, with an exacerbated increase in Ccl2 and Hmox1 in TBI + K. pneumoniae mice compared to either TBI or K. pneumoniae alone. However, the presence of neuroinflammatory immune cells in the injured brain, and the extent of damage to cortical and hippocampal brain tissue, was comparable between K. pneumoniae and vehicle-treated mice by 7 days. Examination of the fecal microbiome across a time course did not reveal any pronounced effects of either injury or K. pneumoniae on bacterial diversity or abundance. Together, these findings demonstrate that K. pneumoniae lung infection after TBI induces an acute and transient inflammatory response, primarily localized to the lungs with some systemic effects. However, this infection had minimal impact on secondary injury processes in the brain following TBI. Future studies are needed to evaluate the potential longer-term consequences of this dual-hit insult.


Assuntos
Lesões Encefálicas Traumáticas , Modelos Animais de Doenças , Infecções por Klebsiella , Klebsiella pneumoniae , Camundongos Endogâmicos C57BL , Animais , Lesões Encefálicas Traumáticas/microbiologia , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/patologia , Camundongos , Infecções por Klebsiella/patologia , Infecções por Klebsiella/microbiologia , Feminino , Masculino , Citocinas/metabolismo , Líquido da Lavagem Broncoalveolar
7.
BMC Microbiol ; 24(1): 168, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760674

RESUMO

BACKGROUND: We aimed to compare the performance of carbapenemase classification in carbapenem-resistant Klebsiella pneumoniae (CRKP) obtained using the BD Phoenix CPO Detect panel (CPO panel) and Cepheid Xpert Carba-R assays. We analyzed 55 CRKP strains from clinical specimens collected between November 2020 and November 2022. The CPO panel was used to detect both antibiotic susceptibility and phenotypic carbapenemase classes, while Xpert Carba-R was employed to identify KPC, NDM, VIM, OXA-48, and IMP genes. Due to the limited availability of molecular kits, we arbitrarily selected 55 isolates, identified as carbapenemase-producing according to the CPO panel and with meropenem minimum inhibitory concentration values > 8 mg/L. RESULTS: According to the Xpert Carba-R assay, 16 of the 55 isolates (29.1%) were categorised as Ambler Class A (11 of which matched CPO panel Class A identification); three isolates (5.5%) were identified as Class B and 27 isolates (49.1%) as Class D (in both cases consistent with CPO panel B and D classifications). A further eight isolates (14.5%) exhibited multiple carbapenemase enzymes and were designated as dual-carbapenemase producers, while one isolate (1.8%) was identified as a non-carbapenemase-producer. The CPO panel demonstrated positive and negative percent agreements of 100% and 85.7% for Ambler Class A, 100% and 100% for Class B, and 96.4% and 100% for Class D carbapenemase detection, respectively. CONCLUSION: While the CPO panel's phenotypic performance was satisfactory in detecting Class B and D carbapenemases, additional confirmatory testing may be necessary for Class A carbapenemases as part of routine laboratory procedures.


Assuntos
Proteínas de Bactérias , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , beta-Lactamases , beta-Lactamases/genética , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/efeitos dos fármacos , Proteínas de Bactérias/genética , Humanos , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/diagnóstico , Antibacterianos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos
8.
J Extracell Vesicles ; 13(5): e12447, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38766978

RESUMO

The continuous emergence of multidrug-resistant bacterial pathogens poses a major global healthcare challenge, with Klebsiella pneumoniae being a prominent threat. We conducted a comprehensive study on K. pneumoniae's antibiotic resistance mechanisms, focusing on outer membrane vesicles (OMVs) and polymyxin, a last-resort antibiotic. Our research demonstrates that OMVs protect bacteria from polymyxins. OMVs derived from Polymyxin B (PB)-stressed K. pneumoniae exhibited heightened protective efficacy due to increased vesiculation, compared to OMVs from unstressed Klebsiella. OMVs also shield bacteria from different bacterial families. This was validated ex vivo and in vivo using precision cut lung slices (PCLS) and Galleria mellonella. In all models, OMVs protected K. pneumoniae from PB and reduced the associated stress response on protein level. We observed significant changes in the lipid composition of OMVs upon PB treatment, affecting their binding capacity to PB. The altered binding capacity of single OMVs from PB stressed K. pneumoniae could be linked to a reduction in the lipid A amount of their released vesicles. Although the amount of lipid A per vesicle is reduced, the overall increase in the number of vesicles results in an increased protection because the sum of lipid A and therefore PB binding sites have increased. This unravels the mechanism of the altered PB protective efficacy of OMVs from PB stressed K. pneumoniae compared to control OMVs. The lipid A-dependent protective effect against PB was confirmed in vitro using artificial vesicles. Moreover, artificial vesicles successfully protected Klebsiella from PB ex vivo and in vivo. The findings indicate that OMVs act as protective shields for bacteria by binding to polymyxins, effectively serving as decoys and preventing antibiotic interaction with the cell surface. Our findings provide valuable insights into the mechanisms underlying antibiotic cross-protection and offer potential avenues for the development of novel therapeutic interventions to address the escalating threat of multidrug-resistant bacterial infections.


Assuntos
Antibacterianos , Klebsiella pneumoniae , Polimixina B , Klebsiella pneumoniae/metabolismo , Klebsiella pneumoniae/efeitos dos fármacos , Antibacterianos/farmacologia , Animais , Polimixina B/farmacologia , Membrana Externa Bacteriana/metabolismo , Polimixinas/farmacologia , Vesículas Extracelulares/metabolismo , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/metabolismo , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos
9.
Antimicrob Resist Infect Control ; 13(1): 54, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38769515

RESUMO

BACKGROUND: Currently, different guidelines recommend using different methods to determine whether deduplication is necessary when determining the detection rates of multidrug-resistant organisms (MDROs). However, few studies have investigated the effect of deduplication on MDRO monitoring data. In this study, we aimed to investigate the influence of deduplication on the detection rates of MDROs in different specimens to assess its impact on infection surveillance outcomes. METHODS: Samples were collected from hospitalized patients admitted between January 2022 and December 2022; four types of specimens were collected from key monitored MDROs, including sputum samples, urine samples, blood samples, and bronchoalveolar lavage fluid (BALF) samples. In this study, we compared and analysed the detection rates of carbapenem-resistant Klebsiella pneumoniae (CRKP), carbapenem-resistant Escherichia coli (CRECO), carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA) under two conditions: with and without deduplication. RESULTS: When all specimens were included, the detection rates of CRKP, CRAB, CRPA, and MRSA without deduplication (33.52%, 77.24%, 44.56%, and 56.58%, respectively) were significantly greater than those with deduplication (24.78%, 66.25%, 36.24%, and 50.83%, respectively) (all P < 0.05). The detection rates in sputum samples were significantly different between samples without duplication (28.39%, 76.19%, 46.95%, and 70.43%) and those with deduplication (19.99%, 63.00%, 38.05%, and 64.50%) (all P < 0.05). When deduplication was not performed, the rate of detection of CRKP in urine samples reached 30.05%, surpassing the rate observed with deduplication (21.56%) (P < 0.05). In BALF specimens, the detection rates of CRKP and CRPA without deduplication (39.78% and 53.23%, respectively) were greater than those with deduplication (31.62% and 42.20%, respectively) (P < 0.05). In blood samples, deduplication did not have a significant impact on the detection rates of MDROs. CONCLUSION: Deduplication had a significant effect on the detection rates of MDROs in sputum, urine, and BALF samples. Based on these data, we call for the Infection Prevention and Control Organization to align its analysis rules with those of the Bacterial Resistance Surveillance Organization when monitoring MDRO detection rates.


Assuntos
Infecção Hospitalar , Farmacorresistência Bacteriana Múltipla , Klebsiella pneumoniae , Escarro , Humanos , Infecção Hospitalar/microbiologia , Infecção Hospitalar/epidemiologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/efeitos dos fármacos , Escarro/microbiologia , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/genética , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Pseudomonas aeruginosa/genética , Líquido da Lavagem Broncoalveolar/microbiologia , Carbapenêmicos/farmacologia , Escherichia coli/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Monitoramento Epidemiológico , Hospitais
10.
PeerJ ; 12: e17328, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38770094

RESUMO

Nanotechnology and nanoparticles have gained massive attention in the scientific community in recent years due to their valuable properties. Among various AgNPs synthesis methods, microbial approaches offer distinct advantages in terms of cost-effectiveness, biocompatibility, and eco-friendliness. In the present research work, investigators have synthesized three different types of silver nanoparticles (AgNPs), namely AgNPs-K, AgNPs-M, and AgNPs-E, by using Klebsiella pneumoniae (MBC34), Micrococcus luteus (MBC23), and Enterobacter aerogenes (MBX6), respectively. The morphological, chemical, and elemental features of the synthesized AgNPs were analyzed by using UV-Vis spectroscopy (UV-Vis), Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy-dispersive spectroscopy (EDX). UV-Vis absorbance peaks were obtained at 475, 428, and 503 nm for AgNPs-K, AgNPs-M, and AgNPs-E, respectively. The XRD analysis confirmed the crystalline nature of the synthesized AgNPs, having peaks at 26.2°, 32.1°, and 47.2°. At the same time, the FTIR showed bands at 599, 963, 1,693, 2,299, 2,891, and 3,780 cm-1 for all the types of AgNPs indicating the presence of bacterial biomolecules with the developed AgNPs. The size and morphology of the AgNPs varied from 10 nm to several microns and exhibited spherical to porous sheets-like structures. The percentage of Ag varied from 37.8% (wt.%) to 61.6%, i.e., highest in AgNPs-K and lowest in AgNPs-M. Furthermore, the synthesized AgNPs exhibited potential for environmental remediation, with AgNPs-M exhibiting the highest removal efficiency (19.24% at 120 min) for methyl orange dye in simulated wastewater. Further, all three types of AgNPs were evaluated for the removal of methyl orange dye from the simulated wastewater, where the highest dye removal percentage was 19.24% at 120 min by AgNPs-M. Antibacterial potential of the synthesized AgNPs assessment against both Gram-positive (GPB) Bacillus subtilis (MBC23), B. cereus (MBC24), and Gram-negative bacteria Enterococcus faecalis (MBP13) revealed promising results, with AgNPs-M, exhibiting the largest zone of inhibition (12 mm) against GPB B. megaterium. Such investigation exhibits the potential of the bacteria for the synthesis of AgNPs with diverse morphology and potential applications in environmental remediation and antibacterial therapy-based synthesis of AgNPs.


Assuntos
Compostos Azo , Nanopartículas Metálicas , Micrococcus luteus , Prata , Prata/química , Prata/farmacologia , Prata/metabolismo , Nanopartículas Metálicas/química , Compostos Azo/química , Compostos Azo/farmacologia , Compostos Azo/metabolismo , Micrococcus luteus/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/metabolismo , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Antibacterianos/química , Enterobacter aerogenes/efeitos dos fármacos , Enterobacter aerogenes/metabolismo , Difração de Raios X , Poluentes Químicos da Água/metabolismo , Corantes/química , Corantes/farmacologia
11.
PLoS One ; 19(5): e0303557, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38771840

RESUMO

BACKGROUND: Urinary tract infections (UTI) is a prevalent condition in those with diabetes, and in severe cases, it may escalate to sepsis. Therefore, it is important to analyze the risk variables associated with sepsis in diabetes individuals with UTI. METHODS: This research was a retrospective cross-sectional analysis. From January 2011 to June 2022, a group of individuals with diabetes were identified as having UTI at a tertiary hospital situated in Southeastern China. Patient data, including information on urine culture, was collected retrospectively from a clinical record database. The participants were categorized into the sepsis and non-sepsis groups. The risk variables were derived using both uni-and multiple- variable regression analysis. RESULTS: The research included 1919 patients, of whom 1106 cases (57.63%) had positive urine cultures. In total, 445 blood culture samples were tested, identifying 186 positive cases (41.80%). The prevalence of bacteria in urine and blood samples was highest for Escherichia coli and Klebsiella pneumoniae, respectively. Moreover, 268 individuals (13.97%) exhibited sepsis. The regression analysis indicated a positive correlation between sepsis and albumin (ALB)<34.35 g/L, C-reactive protein (CRP)>55.84 mg/L and white blood cell count (WBC) >8.485 X 109/L in diabetic cases with UTIs. By integrating the three aforementioned parameters, the area under the receiver operating characteristic curve was 0.809. CONCLUSIONS: The early detection of sepsis in diabetic individuals with UTI may be achieved using a comprehensive analysis of CRP, WBC, and ALB test findings.


Assuntos
Sepse , Infecções Urinárias , Humanos , Infecções Urinárias/complicações , Infecções Urinárias/microbiologia , Infecções Urinárias/epidemiologia , Masculino , Feminino , Sepse/complicações , Sepse/epidemiologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Idoso , Estudos Transversais , Fatores de Risco , China/epidemiologia , Proteína C-Reativa/análise , Proteína C-Reativa/metabolismo , Diabetes Mellitus/epidemiologia , Adulto , Klebsiella pneumoniae/isolamento & purificação , Contagem de Leucócitos , Complicações do Diabetes/microbiologia , Complicações do Diabetes/epidemiologia
12.
J Assoc Physicians India ; 72(1): 43-46, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38736073

RESUMO

INTRODUCTION: A survey-based approach to managing antibiotic-resistant infections in the intensive care unit (ICU) setting, with a focus on carbapenem-resistant Enterobacteriaceae (CRE) cases, was conducted. Among CRE, New Delhi metallo-ß-lactamase 1 (NDM-1) is a carbapenemase that is resistant to ß-lactam antibiotics and has a broader spectrum of antimicrobial resistance than other carbapenemase types. The article explains that healthcare-associated infections (HAIs) are a significant problem, particularly in low- and middle-income countries, and that carbapenem in combination with other antibiotics are the most potent class of antimicrobial agents effective in treating life-threatening bacterial infections, including those caused by resistant strains. AIM: The survey aimed to gather critical care healthcare professionals (HCPs') opinions on their current practices in managing infections acquired in the hospital and ICU settings, with a focus on CRE cases, specifically NDM-1 and other antibiotic-resistant infections. METHODS: Responses from critical care healthcare professionals, including online surveys and in-person interviews, to gain insights into the management of infections caused by multidrug-resistant bacteria. The findings related to the insights on the prevalence of bacterial flora, clinical experiences on efficacy and safety of meropenem sulbactam ethylenediaminetetraacetic acid (EDTA) (MSE) in CRE cases, and various combination therapies of antibiotics used to treat antibiotic-resistant infections in ICU setting were evaluated. RESULTS: Klebsiella pneumoniae bacteria were the most common bacteria in cultures, followed by Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. NDM-1 was the type of carbapenemase found in around 50% of CRE patients. MSE is among the most preferred antibiotics besides colistin, polymyxin B, and ceftazidime avibactum for CRE cases and specifically for NDM-1 cases due to its high rate of efficacy and safety. CONCLUSION: The article concludes with a discussion on the antibiotics used in response to CRE cases, reporting that critical care HCP considers MSE with high efficacy and safe antibiotic combination and was used as both monotherapy and in combination with other antibiotics. The survey highlights the need for exploring and better understanding the role of MSE in the management of CRE infections, especially in NDM-1.


Assuntos
Antibacterianos , Enterobacteriáceas Resistentes a Carbapenêmicos , Cuidados Críticos , Infecções por Enterobacteriaceae , Unidades de Terapia Intensiva , Humanos , Antibacterianos/uso terapêutico , Infecções por Enterobacteriaceae/tratamento farmacológico , Cuidados Críticos/métodos , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Inquéritos e Questionários , beta-Lactamases , Farmacorresistência Bacteriana Múltipla , Meropeném/uso terapêutico , Índia , Atitude do Pessoal de Saúde , Polimixina B/uso terapêutico , Carbapenêmicos/uso terapêutico , Carbapenêmicos/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Pessoal de Saúde
13.
Nat Commun ; 15(1): 3947, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38729951

RESUMO

Gram-negative bacteria (GNB) are a major cause of neonatal sepsis in low- and middle-income countries (LMICs). Although the World Health Organization (WHO) reports that over 80% of these sepsis deaths could be prevented through improved treatment, the efficacy of the currently recommended first- and second-line treatment regimens for this condition is increasingly affected by high rates of drug resistance. Here we assess three well known antibiotics, fosfomycin, flomoxef and amikacin, in combination as potential antibiotic treatment regimens by investigating the drug resistance and genetic profiles of commonly isolated GNB causing neonatal sepsis in LMICs. The five most prevalent bacterial isolates in the NeoOBS study (NCT03721302) are Klebsiella pneumoniae, Acinetobacter baumannii, E. coli, Serratia marcescens and Enterobacter cloacae complex. Among these isolates, high levels of ESBL and carbapenemase encoding genes are detected along with resistance to ampicillin, gentamicin and cefotaxime, the current WHO recommended empiric regimens. The three new combinations show excellent in vitro activity against ESBL-producing K. pneumoniae and E. coli isolates. Our data should further inform and support the clinical evaluation of these three antibiotic combinations for the treatment of neonatal sepsis in areas with high rates of multidrug-resistant Gram-negative bacteria.


Assuntos
Acinetobacter baumannii , Antibacterianos , Bactérias Gram-Negativas , Infecções por Bactérias Gram-Negativas , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Sepse Neonatal , Humanos , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Sepse Neonatal/microbiologia , Sepse Neonatal/tratamento farmacológico , Recém-Nascido , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/genética , Amicacina/farmacologia , Amicacina/uso terapêutico , Fosfomicina/farmacologia , Fosfomicina/uso terapêutico , beta-Lactamases/genética , beta-Lactamases/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Países em Desenvolvimento , Farmacorresistência Bacteriana Múltipla/genética , Quimioterapia Combinada , Serratia marcescens/efeitos dos fármacos , Serratia marcescens/genética , Serratia marcescens/isolamento & purificação , Enterobacter cloacae/efeitos dos fármacos , Enterobacter cloacae/genética , Enterobacter cloacae/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo
14.
Nat Commun ; 15(1): 3981, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730266

RESUMO

Heteroresistance is a medically relevant phenotype where small antibiotic-resistant subpopulations coexist within predominantly susceptible bacterial populations. Heteroresistance reduces treatment efficacy across diverse bacterial species and antibiotic classes, yet its genetic and physiological mechanisms remain poorly understood. Here, we investigated a multi-resistant Klebsiella pneumoniae isolate and identified three primary drivers of gene dosage-dependent heteroresistance for several antibiotic classes: tandem amplification, increased plasmid copy number, and transposition of resistance genes onto cryptic plasmids. All three mechanisms imposed fitness costs and were genetically unstable, leading to fast reversion to susceptibility in the absence of antibiotics. We used a mouse gut colonization model to show that heteroresistance due to elevated resistance-gene dosage can result in antibiotic treatment failures. Importantly, we observed that the three mechanisms are prevalent among Escherichia coli bloodstream isolates. Our findings underscore the necessity for treatment strategies that address the complex interplay between plasmids, resistance cassettes, and transposons in bacterial populations.


Assuntos
Antibacterianos , Variações do Número de Cópias de DNA , Escherichia coli , Klebsiella pneumoniae , Plasmídeos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Camundongos , Plasmídeos/genética , Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Testes de Sensibilidade Microbiana , Dosagem de Genes , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/tratamento farmacológico , Humanos , Elementos de DNA Transponíveis/genética , Feminino
15.
Virulence ; 15(1): 2349768, 2024 12.
Artigo em Inglês | MEDLINE | ID: mdl-38736039

RESUMO

ST11 is the most common lineage among carbapenem-resistant Klebsiella pneumoniae (CRKP) infections in Asia. Diverse morphotypes resulting from genetic mutations are associated with significant differences in microbial characteristics among K. pneumoniae isolates. Here, we investigated the genetic determinants and critical characteristics associated with distinct morphotypes of ST11 CRKP. An ST11-KL47 CRKP isolate carrying a pLVPK-like virulence plasmid was isolated from a patient with a bloodstream infection; the isolate had the "mcsw" morphotype. Two distinct morphotypes ("ntrd" and "msdw") were derived from this strain during in vitro passage. Whole genome sequencing was used to identify mutations that cause the distinct morphotypes of ST11 CRKP. Transmission electron microscopy, antimicrobial susceptibility tests, growth assays, biofilm formation, virulence assays, membrane permeability assays, and RNA-seq analysis were used to investigate the specific characteristics associated with different morphotypes of ST11 CRKP. Compared with the parental mcsw morphotype, the ntrd morphotype resulted from mutation of genes involved in capsular polysaccharide biosynthesis (wza, wzc, and wbaP), a result validated by gene knockout experiments. This morphotype showed capsule deficiency and lower virulence potential, but higher biofilm production. By contrast, the msdw morphotype displayed competition deficiency and increased susceptibility to chlorhexidine and polymyxin B. Further analyses indicated that these characteristics were caused by interruption of the sigma factor gene rpoN by insertion mutations and deletion of the rpoN gene, which attenuated membrane integrity presumably by downregulating the phage shock protein operon. These data expand current understanding of genetic, virulence, and antimicrobial resistance characteristics associated with distinct morphotypes in ST11 CRKP.


Assuntos
Antibacterianos , Biofilmes , Carbapenêmicos , Infecções por Klebsiella , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Virulência , Infecções por Klebsiella/microbiologia , Humanos , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Carbapenêmicos/farmacologia , Animais , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Camundongos , Mutação , Sequenciamento Completo do Genoma , Plasmídeos/genética , Farmacorresistência Bacteriana
16.
Nat Commun ; 15(1): 4187, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760381

RESUMO

Hypervirulent Klebsiella pneumoniae (hvKp) is a significant cause of severe invasive infections in Vietnam, yet data on its epidemiology, population structure and dynamics are scarce. We screened hvKp isolates from patients with bloodstream infections (BSIs) at a tertiary infectious diseases hospital in Vietnam and healthy individuals, followed by whole genome sequencing and plasmid analysis. Among 700 BSI-causing Kp strains, 100 (14.3%) were hvKp. Thirteen hvKp isolates were identified from 350 rectal swabs of healthy adults; none from 500 rectal swabs of healthy children. The hvKp isolates were genetically diverse, encompassing 17 sequence types (STs), predominantly ST23, ST86 and ST65. Among the 113 hvKp isolates, 14 (12.6%) carried at least one antimicrobial resistance (AMR) gene, largely mediated by IncFII, IncR, and IncA/C plasmids. Notably, the acquisition of AMR conjugative plasmids facilitated horizontal transfer of the non-conjugative virulence plasmid between K. pneumoniae strains. Phylogenetic analysis demonstrated hvKp isolates from BSIs and human carriage clustered together, suggesting a significant role of intestinal carriage in hvKp transmission. Enhanced surveillance is crucial to understand the factors driving intestinal carriage and hvKp transmission dynamics for informing preventive measures. Furthermore, we advocate the clinical use of our molecular assay for diagnosing hvKp infections to guide effective management.


Assuntos
Infecções por Klebsiella , Klebsiella pneumoniae , Filogenia , Plasmídeos , Sequenciamento Completo do Genoma , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Klebsiella pneumoniae/isolamento & purificação , Vietnã/epidemiologia , Humanos , Plasmídeos/genética , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Virulência/genética , Adulto , Feminino , Transferência Genética Horizontal , Masculino , Genoma Bacteriano , Pessoa de Meia-Idade , Antibacterianos/farmacologia , Criança , Genômica , Farmacorresistência Bacteriana/genética
17.
Front Cell Infect Microbiol ; 14: 1297312, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38690325

RESUMO

Background: During the coronavirus disease 2019 (COVID-19) pandemic, in patients treated for SARS-CoV-2 infection, infections with the Klebsiella pneumoniae bacteria producing New Delhi metallo-B-lactamase (NDM) carbapenemase in the USA, Brazil, Mexico, and Italy were observed, especially in intensive care units (ICUs). This study aimed to assess the impact of Klebsiella pneumoniae NDM infection and other bacterial infections on mortality in patients treated in ICUs due to COVID-19. Methods: The 160 patients who qualified for the study were hospitalized in ICUs due to COVID-19. Three groups were distinguished: patients with COVID-19 infection only (N = 72), patients with COVID-19 infection and infection caused by Klebsiella pneumoniae NDM (N = 30), and patients with COVID-19 infection and infection of bacterial etiology other than Klebsiella pneumoniae NDM (N = 58). Mortality in the groups and chosen demographic data; biochemical parameters analyzed on days 1, 3, 5, and 7; comorbidities; and ICU scores were analyzed. Results: Bacterial infection, including with Klebsiella pneumoniae NDM type, did not elevate mortality rates. In the group of patients who survived the acute phase of COVID-19 the prolonged survival time was demonstrated: the median overall survival time was 13 days in the NDM bacterial infection group, 14 days in the other bacterial infection group, and 7 days in the COVID-19 only group. Comparing the COVID-19 with NDM infection and COVID-19 only groups, the adjusted model estimated a statistically significant hazard ratio of 0.28 (p = 0.002). Multivariate analysis revealed that age, APACHE II score, and CRP were predictors of mortality in all the patient groups. Conclusion: In patients treated for SARS-CoV-2 infection acquiring a bacterial infection due to prolonged hospitalization associated with the treatment of COVID-19 did not elevate mortality rates. The data suggests that in severe COVID-19 patients who survived beyond the first week of hospitalization, bacterial infections, particularly Klebsiella pneumoniae NDM, do not significantly impact mortality. Multivariate analysis revealed that age, APACHE II score, and CRP were predictors of mortality in all the patient groups.


Assuntos
COVID-19 , Farmacorresistência Bacteriana Múltipla , Unidades de Terapia Intensiva , Infecções por Klebsiella , Klebsiella pneumoniae , SARS-CoV-2 , beta-Lactamases , Humanos , COVID-19/mortalidade , COVID-19/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Masculino , Feminino , Infecções por Klebsiella/mortalidade , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/epidemiologia , beta-Lactamases/metabolismo , beta-Lactamases/genética , Pessoa de Meia-Idade , Idoso , Adulto , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Idoso de 80 Anos ou mais
18.
J Clin Invest ; 134(9)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38690730

RESUMO

The gut microbiota is an integral part of the human metaorganism that is required to shape physiologic host immune responses including host defense against pathogens. Disease-associated gut dysbiosis has been characterized by blooms of pathobionts, which are bacterial species that can drive disease under certain conditions. Pathobionts like Enterobacteriaceae often bloom during flares of inflammatory bowel disease (IBD) and are causally linked with IBD in murine models. In this issue of the JCI, Hecht and colleagues investigated how simple carbohydrates are causally linked to the bloom of the gut pathobiont Klebsiella pneumoniae, which belong to the Enterobacteriaceae family. Notably, the presence of fiber reduced the dissemination of K. pneumoniae into the blood and liver in a colitis model. Their findings provide a diet-related mechanism for gut dysbiosis, which has implications in the management of IBD and other conditions in which gut dysbiosis is an underlying factor.


Assuntos
Disbiose , Microbioma Gastrointestinal , Doenças Inflamatórias Intestinais , Klebsiella pneumoniae , Humanos , Animais , Doenças Inflamatórias Intestinais/microbiologia , Camundongos , Carboidratos da Dieta/efeitos adversos , Infecções por Klebsiella , Colite/induzido quimicamente , Colite/microbiologia , Fibras na Dieta
19.
BMC Immunol ; 25(1): 27, 2024 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-38706005

RESUMO

BACKGROUND: Due to antibiotic resistance, the Klebsiella genus is linked to morbidity and death, necessitating the development of a universally protective vaccine against Klebsiella pathogens. METHODS: Core sequence analysis prioritized non-redundant host molecules and expected lipid bilayer peptides from fully sequenced Klebsiella genomes. These proteins were refined to identify epitopes, examining their immunogenicity, toxicity, solubility, and interaction with MHC alleles. Epitopes were linked to CPG ODN C274 via EAAAK, HEYGAEALERAG, and GGGS linkers to enhance immunological responses. The vaccine's tertiary structure was modelled and docked with MHC-I and MHC-II. RESULTS: Fifty-five proteins were recognized in the Vaxign collection as having remarkable features. Twenty-three proteins with potential pathogenicity were then identified. Eight options for vaccines emerged after the immunogenicity of proteins was examined. The best antigens were three proteins: MrkD, Iron-regulated lipid membrane polypeptides, and RmpA. These compounds were selected for their sensitivity. The structural protein sequences of K. pneumoniae were utilized to identify seven CTL epitopes, seven HTL epitopes, and seven LBL epitopes, respectively. The produced immunization displayed a stable contact with the receptors, based on molecular dynamic simulations lasting 250 nanoseconds. Intermolecular binding free energies also indicated the dominance of the van der Waals and electrostatic energies. CONCLUSION: In summary, the results of this study might help scientists develop a novel vaccine to prevent K. pneumoniae infections.


Assuntos
Vacinas Bacterianas , Infecções por Klebsiella , Klebsiella pneumoniae , Klebsiella pneumoniae/imunologia , Vacinas Bacterianas/imunologia , Infecções por Klebsiella/imunologia , Infecções por Klebsiella/prevenção & controle , Animais , Epitopos de Linfócito T/imunologia , Camundongos , Humanos , Simulação de Dinâmica Molecular , Antígenos de Bactérias/imunologia , Oligodesoxirribonucleotídeos/imunologia , Epitopos/imunologia , Simulação de Acoplamento Molecular
20.
Nan Fang Yi Ke Da Xue Xue Bao ; 44(4): 757-764, 2024 Apr 20.
Artigo em Chinês | MEDLINE | ID: mdl-38708510

RESUMO

OBJECTIVE: To explore the effect of intestinal nitrates on the growth of Klebsiella pneumoniae and its regulatory mechanisms. METHODS: K. pneumoniae strains with nitrate reductase narG and narZ single or double gene knockout or with NarXL gene knockout were constructed and observed for both aerobic and anaerobic growth in the presence of KNO3 using an automated bacterial growth analyzer and a spectrophotometer, respectively. The mRNA expressions of narG and narZ in K. pneumoniae in anaerobic cultures in the presence of KNO3 and the effect of the binary regulatory system NarXL on their expresisons were detected using qRT-PCR. Electrophoretic mobility shift assays (EMSA) and MST analysis were performed to explore the specific regulatory mechanisms of NarXL in sensing and utilizing nitrates. Competitive experiments were conducted to examine anaerobic growth advantages of narG and narZ gene knockout strains of K. pneumoniae in the presence of KNO3. RESULTS: The presence of KNO3 in anaerobic conditions, but not in aerobic conditions, promoted bacterial growth more effectively in the wild-type K. pneumoniae strain than in the narXL gene knockout strain. In anaerobic conditions, the narXL gene knockout strain showed significantly lowered mRNA expressions of narG and narZ (P < 0.0001). EMSA and MST experiments demonstrated that the NarXL regulator could directly bind to narG and narZ promoter regions. The wild-type K. pneumoniae strain in anaerobic cultures showed significantly increased expressions of narG and narZ mRNAs in the presence of KNO3 (P < 0.01), and narG gene knockout resulted in significantly attenuated anaerobic growth and competitive growth abilities of K. pneumoniae in the presence of KNO3 (P < 0.01). CONCLUSION: The binary regulatory system NarXL of K. pneumoniae can sense changes in intestinal nitrate concentration and directly regulate the expression of nitrate reductase genes narG and narZ to promote bacterial growth.


Assuntos
Klebsiella pneumoniae , Nitrato Redutase , Nitratos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Klebsiella pneumoniae/efeitos dos fármacos , Nitratos/metabolismo , Nitratos/farmacologia , Nitrato Redutase/metabolismo , Nitrato Redutase/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Intestinos/microbiologia , Regulação Bacteriana da Expressão Gênica , Anaerobiose , Técnicas de Inativação de Genes
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