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Trends in Microbiology Jan 2024is a Gram negative, facultative intracellular bacterium that resides in the rhizosphere of tropical soils. causes melioidosis, which is transmitted by cutaneous entry,...
is a Gram negative, facultative intracellular bacterium that resides in the rhizosphere of tropical soils. causes melioidosis, which is transmitted by cutaneous entry, ingestion, or inhalation of contaminated soil or water. Infection with can cause a wide array of clinical symptoms such as pneumonia, bone, joint, skin, genitourinary, and central nervous system infections, as well as parotid abscesses in children. Mammalian virulence is linked to the intracellular life cycle, which begins with attachment and internalization by host cells. can infect a wide range of eukaryotic cells, including macrophages, monocytes, and neutrophils, as well as nonphagocytic cells. Once internalized, a type 3 secretion system (T3SS) facilitates escape from the phagosome, and the bacteria replicate in the cytoplasm. Autotransporter protein BimA mediates actin polymerization, enabling to spread, cell to cell, using actin-based motility. This process, coupled with the activity of a type 6 secretion system (T6SS-5), results in host membrane fusion and the formation of multinucleated giant cells. Capsule polysaccharides also contribute to virulence and evasion of host innate immunity. Treatment of infections is complicated by the organism’s intrinsic resistance to multiple classes of antimicrobials, largely due to an abundance of efflux pumps and reduced outer membrane permeability. While is commonly associated with endemic ‘hotspots’ in southeast Asia and northern Australia, there is increasing evidence that it is likely endemic in a large range of tropical and subtropical areas, including regions in Africa, South America, the Middle East, Central America, and the Caribbean. Soil and climate conditions favorable for survival are also found in additional areas worldwide. Consequently, it is important for clinical and public health laboratories located outside of high-endemicity areas to be aware of , as well as for improved diagnostic and reporting methods.
Topics: Burkholderia pseudomallei; Burkholderia
PubMed: 37634974
DOI: 10.1016/j.tim.2023.07.008 -
Frontiers in Cellular and Infection... 2023Sleep deprivation has developed into a common phenomenon, which can lead to inflammatory responses and cognitive impairment, but the underlying mechanism is ambiguous....
OBJECTIVE
Sleep deprivation has developed into a common phenomenon, which can lead to inflammatory responses and cognitive impairment, but the underlying mechanism is ambiguous. Emerging evidence shows that gut microbiota plays a crucial role in theoccurrence and development of inflammatory and psychiatric diseases, possibly through neuroinflammation and the brain-gut axis. The current study investigated the influence of sleep deprivation on gut microbiota composition, pro-inflammatory cytokines, learning and memory in mice. Further, it explored whether changes in gut microbiota increase pro-inflammatory cytokine and induce learning and memory impairment.
METHODS
Healthy 8-week-old male C57BL/6J mice were randomly divided into the regular control group (RC), environmental control group (EC), and sleep deprivation group (SD). The sleep deprivation model was established by the Modified Multiple Platform Method. The experimental mice were subjected to sleep deprivation for 6h/d (8:00 am∼14:00 pm) in a sleep deprivation chamber, and the duration of sleep deprivation was 8 weeks. Morris water maze test to assess learning and memory in mice. Enzyme-Linked Immunosorbent Assay determined the concentrations of inflammatory cytokines. The changes in gut microbiota in mice were analyzed by 16S rRNA sequencing.
RESULTS
We found that SD mice had elevated latency of exploration to reach the hidden platform (p>0.05) and significantly decreased traversing times, swimming distance, and swimming time in the target zone when the hidden platform was removed (p<0.05). Sleep deprivation caused dysregulated expression in serum IL-1β, IL-6, and TNF-α in mice, and the difference was significant (all p<0.001). Tannerellaceae, Rhodospirillales, Alistipes, and Parabacteroides were significantly increased in SD mice. Correlation analysis showed IL-1β was positively correlated with the abundance of Muribaculaceae (r=0.497, p<0.05) and negatively correlated with the abundance of Lachnospiraceae (r=-0.583, p<0.05). The TNF-α was positively correlated with the abundances of Erysipelotrichaceae, Burkholderiaceae, and Tannerellaceae (r=0.492, r=0.646, r=0.726, all p<0.05).
CONCLUSION
Sleep deprivation can increase pro-inflammatory cytokine responses and learning and memory impairment in mice and may be caused by the disorder of the microbiota. These findings of this study may open avenues for potential interventions that can relieve the detrimental consequences of sleep loss.
Topics: Mice; Male; Animals; Sleep Deprivation; Gastrointestinal Microbiome; Tumor Necrosis Factor-alpha; RNA, Ribosomal, 16S; Mice, Inbred C57BL; Cytokines
PubMed: 37293204
DOI: 10.3389/fcimb.2023.1159771 -
Annual Review of Microbiology Sep 2023species complex (RSSC) strains are devastating plant pathogens distributed worldwide. The primary cell density-dependent gene expression system in RSSC strains is... (Review)
Review
species complex (RSSC) strains are devastating plant pathogens distributed worldwide. The primary cell density-dependent gene expression system in RSSC strains is quorum sensing (QS). It regulates the expression of about 30% of all genes, including those related to cellular activity, primary and secondary metabolism, pathogenicity, and more. The regulatory elements encoded by the operon and gene play vital roles. RSSC strains use methyl 3-hydroxymyristate (3-OH MAME) or methyl 3-hydroxypalmitate (3-OH PAME) as the QS signal. Each type of RSSC strain has specificity in generating and receiving its QS signal, but their signaling pathways might not differ significantly. In this review, I describe the genetic and biochemical factors involved in QS signal input and the regulatory network and summarize control of the QS system, new cell-cell communications, and QS-dependent interactions with soil fungi.
Topics: Quorum Sensing; Ralstonia solanacearum; Virulence; Signal Transduction
PubMed: 37100406
DOI: 10.1146/annurev-micro-032521-030537 -
Antimicrobial Agents and Chemotherapy Jun 2023Cefiderocol is a siderophore cephalosporin designed mainly for treatment of infections caused by β-lactam and multidrug-resistant Gram-negative bacteria. Burkholderia...
Cefiderocol is a siderophore cephalosporin designed mainly for treatment of infections caused by β-lactam and multidrug-resistant Gram-negative bacteria. Burkholderia pseudomallei clinical isolates are usually highly cefiderocol susceptible, with resistance found in a few isolates. Resistance in clinical B. pseudomallei isolates from Australia is caused by a hitherto uncharacterized mechanism. We show that, like in other Gram-negatives, the PiuA outer membrane receptor plays a major role in cefiderocol nonsusceptibility in isolates from Malaysia.
Topics: Anti-Bacterial Agents; Burkholderia pseudomallei; Gram-Negative Bacteria; Cephalosporins; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Cefiderocol
PubMed: 37133377
DOI: 10.1128/aac.00171-23 -
The American Journal of Tropical... Jun 2023
Topics: Humans; Burkholderia pseudomallei; Melioidosis
PubMed: 37160279
DOI: 10.4269/ajtmh.23-0223 -
The International Journal of... Oct 2023Melioidosis is a potentially life-threatening infection caused by the Gram-negative bacillus . Mediastinal melioidosis has a range of clinical presentations, making it... (Review)
Review
Melioidosis is a potentially life-threatening infection caused by the Gram-negative bacillus . Mediastinal melioidosis has a range of clinical presentations, making it difficult to diagnose: we therefore reviewed the evidence on the clinical characteristics, radiological features and invasive diagnostic modalities or interventions. An electronic search was conducted on three databases (PubMed, SCOPUS, Google Scholar) from November to December 2022. The initial search yielded 120 results, of which 34 studies met the inclusion criteria, but only 31 full-texts were retrievable. Among these, 4 were cohort studies, 26 case reports or series and 1 a conference abstract. The four main themes covered were mediastinal melioidosis as a diagnostic dilemma, unexpected complications, invasive interventions or an accompanying thoracic feature. Radiological manifestations included matting, necrosis and abscess-like collection. Severe presentations of mediastinal melioidosis included superior vena cava obstruction, sinus tract formation and pericardial tamponade. Transbronchial needle aspiration was the most common invasive diagnostic modality. Further research is needed to understand the relationship between the thoracic features of melioidosis on patient prognosis, its relationship to melioidosis transmission and potential preventive measures.
Topics: Humans; Burkholderia pseudomallei; Melioidosis; Radiography; Vena Cava, Superior
PubMed: 37749834
DOI: 10.5588/ijtld.23.0079 -
and activity of cefiderocol against spp. and complex, including carbapenem-non-susceptible isolates.Antimicrobial Agents and Chemotherapy Dec 2023spp. and complex (Bcc) are rare but diverse opportunistic pathogens associated with serious infections, which are often multidrug resistant. This study compared the...
spp. and complex (Bcc) are rare but diverse opportunistic pathogens associated with serious infections, which are often multidrug resistant. This study compared the antibacterial activity of the siderophore antibiotic cefiderocol against spp. and Bcc isolates with that of other approved antibacterial drugs, including ceftazidime-avibactam, ciprofloxacin, colistin, imipenem-relebactam, and meropenem-vaborbactam. Isolates were collected in the SIDERO multinational surveillance program. Among 334 spp. isolates [76.6% from respiratory tract infections (RTIs)], cefiderocol had minimum inhibitory concentration (MIC) of 0.06/0.5 µg/mL overall and 0.5/4 µg/mL against 52 (15.6%) carbapenem-non-susceptible (Carb-NS) isolates. Eleven (3.3%) spp. isolates overall and 6 (11.5%) Carb-NS isolates were not susceptible to cefiderocol. Among 425 Bcc isolates (73.4% from RTIs), cefiderocol had MIC of ≤0.03/0.5 µg/mL overall and ≤0.03/1 µg/mL against 184 (43.3%) Carb-NS isolates. Twenty-two (5.2%) Bcc isolates overall and 13 (7.1%) Carb-NS isolates were not susceptible to cefiderocol. Cumulative MIC distributions showed cefiderocol to be the most active of the agents tested against both spp. and Bcc. In a neutropenic murine lung infection model and a humanized pharmacokinetic immunocompetent rat lung infection model, cefiderocol showed significant bactericidal activity against two meropenem-resistant strains compared with untreated controls ( < 0.05) and vehicle-treated controls ( < 0.05), respectively. Meropenem, piperacillin-tazobactam, ceftazidime, and ciprofloxacin comparators showed no significant activity in these models. The results suggest that cefiderocol could be a possible treatment option for RTIs caused by spp. and Bcc.
Topics: Rats; Animals; Mice; Cefiderocol; Meropenem; Carbapenems; Cephalosporins; Burkholderia cepacia complex; Achromobacter; Drug Resistance, Multiple, Bacterial; Anti-Bacterial Agents; Ceftazidime; Respiratory Tract Infections; Ciprofloxacin; Microbial Sensitivity Tests
PubMed: 37971240
DOI: 10.1128/aac.00346-23 -
American Journal of Respiratory and... Feb 2024The global burden of sepsis is greatest in low-resource settings. Melioidosis, infection with the gram-negative bacterium , is a frequent cause of fatal sepsis in...
The global burden of sepsis is greatest in low-resource settings. Melioidosis, infection with the gram-negative bacterium , is a frequent cause of fatal sepsis in endemic tropical regions such as Southeast Asia. To investigate whether plasma metabolomics would identify biological pathways specific to melioidosis and yield clinically meaningful biomarkers. Using a comprehensive approach, differential enrichment of plasma metabolites and pathways was systematically evaluated in individuals selected from a prospective cohort of patients hospitalized in rural Thailand with infection. Statistical and bioinformatics methods were used to distinguish metabolomic features and processes specific to patients with melioidosis and between fatal and nonfatal cases. Metabolomic profiling and pathway enrichment analysis of plasma samples from patients with melioidosis ( = 175) and nonmelioidosis infections ( = 75) revealed a distinct immuno-metabolic state among patients with melioidosis, as suggested by excessive tryptophan catabolism in the kynurenine pathway and significantly increased levels of sphingomyelins and ceramide species. We derived a 12-metabolite classifier to distinguish melioidosis from other infections, yielding an area under the receiver operating characteristic curve of 0.87 in a second validation set of patients. Melioidosis nonsurvivors ( = 94) had a significantly disturbed metabolome compared with survivors ( = 81), with increased leucine, isoleucine, and valine metabolism, and elevated circulating free fatty acids and acylcarnitines. A limited eight-metabolite panel showed promise as an early prognosticator of mortality in melioidosis. Melioidosis induces a distinct metabolomic state that can be examined to distinguish underlying pathophysiological mechanisms associated with death. A 12-metabolite signature accurately differentiates melioidosis from other infections and may have diagnostic applications.
Topics: Humans; Melioidosis; Prospective Studies; Burkholderia pseudomallei; Sepsis; Metabolomics
PubMed: 37812796
DOI: 10.1164/rccm.202207-1349OC -
Journal of Infection in Developing... Jun 2023A 12-year-old boy was admitted after 11 days of fever and 2 days of nasal obstruction as well as swelling of a right cervical lymph node. Nasal endoscopy and computed...
A 12-year-old boy was admitted after 11 days of fever and 2 days of nasal obstruction as well as swelling of a right cervical lymph node. Nasal endoscopy and computed tomography of the neck showed a nasopharyngeal mass occupying the entire nasopharynx, extending into the nasal cavity, and obliterating the fossa of Rosenmuller. Abdominal ultrasonography revealed a small solitary splenic abscess. Although a nasopharyngeal tumor or malignancy was initially considered, biopsy of the mass showed only suppurative granulomatous inflammation, and bacterial culture from the enlarged cervical lymph node yielded Burkholderia pseudomallei. The symptoms, nasopharyngeal mass, and cervical lymph node enlargement resolved with melioidosis-directed antibiotic therapy. Although rarely reported, the nasopharynx may be an important primary site of infection in melioidosis patients, especially in pediatric patients.
Topics: Male; Humans; Child; Melioidosis; Splenic Diseases; Nasopharyngeal Neoplasms; Burkholderia pseudomallei; Anti-Bacterial Agents; Lymphadenopathy; Nasopharynx
PubMed: 37406064
DOI: 10.3855/jidc.17821 -
Proceedings of the National Academy of... Jul 2023BpeB and BpeF are multidrug efflux transporters from that enable multidrug resistance. Here, we report the crystal structures of BpeB and BpeF at 2.94 Å and 3.0 Å...
BpeB and BpeF are multidrug efflux transporters from that enable multidrug resistance. Here, we report the crystal structures of BpeB and BpeF at 2.94 Å and 3.0 Å resolution, respectively. BpeB was found as an asymmetric trimer, consistent with the widely-accepted functional rotation mechanism for this type of transporter. One of the monomers has a distinct structure that we interpret as an intermediate along this functional cycle. Additionally, a detergent molecule bound in a previously undescribed binding site provides insights into substrate translocation through the pathway. BpeF shares structural similarities with the crystal structure of OqxB from , where both are symmetric trimers composed of three "binding"-state monomers. The structures of BpeB and BpeF further our understanding of the functional mechanisms of transporters belonging to the HAE1-RND superfamily.
Topics: Burkholderia pseudomallei; Membrane Transport Proteins; Biological Transport; Drug Resistance, Multiple; Binding Sites; Anti-Bacterial Agents
PubMed: 37428905
DOI: 10.1073/pnas.2215072120