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Foods (Basel, Switzerland) Oct 2023Bongkrekic acid (BKA) poisoning, induced by the contamination of pathovar , has a long-standing history of causing severe outbreaks of foodborne illness. In recent... (Review)
Review
Bongkrekic acid (BKA) poisoning, induced by the contamination of pathovar , has a long-standing history of causing severe outbreaks of foodborne illness. In recent years, it has emerged as a lethal food safety concern, presenting significant challenges to public health. This review article highlights the recent incidents of BKA poisoning and current research discoveries on the pathogenicity of pv. and underlying biochemical mechanisms for BKA synthesis. Moreover, the characterization of pv. and the identification of the gene cluster provide a crucial foundation for developing targeted interventions to prevent BKA accumulation in food matrices. The prevalence of the gene cluster, which is the determining factor distinguishing pv. from non-pathogenic strains, has been identified in 15% of documented genomes worldwide. This finding suggests that BKA poisoning has the potential to evolve into a more prevalent threat. Although limited, previous research has proved that pv. is capable of producing BKA in diverse environments, emphasizing the possible food safety hazards associated with BKA poisoning. Also, advancements in detection methods of both BKA and pv. hold great promise for mitigating the impact of this foodborne disease. Future studies focusing on reducing the threat raised by this vicious foe is of paramount importance to public health.
PubMed: 37959045
DOI: 10.3390/foods12213926 -
Comparative Medicine Oct 2023Four strains of experimentally naïve mice (NOD. Cg- Il2rg /SzJ [NSG], NOD. Cg- /SzJ [NRG], B6.129S(Cg)-/J [STAT1 ], and B6.129S7- /J[IFNγR ] housed in a barrier...
Four strains of experimentally naïve mice (NOD. Cg- Il2rg /SzJ [NSG], NOD. Cg- /SzJ [NRG], B6.129S(Cg)-/J [STAT1 ], and B6.129S7- /J[IFNγR ] housed in a barrier facility developed unusual and seemingly unrelated clinical signs. Young NSG/NRG mice ( = 49, mean age = 4 ± 0.4 mo) exhibited nonspecific clinical signs of moderate-to-severe lethargy, hunched posture, decreased body condition, and pallor. In contrast to the NSG/NRG mice, the STAT1 and IFNγ R mice ( = 5) developed large subcutaneous abscesses on the head and neck. These mice were euthanized, and samples were collected for culture. NSG/NRG mice had moderate-markedly enlarged livers (20 of 49, 40%) and spleens (17 of 49, 35%). The livers contained multiple, variably-sized, tan regions throughout all lobes. Histology revealed necrotizing hepatitis (13 of 17, 77%), splenic and hepatic extramedullary hematopoiesis (17 of 17, 100%), glomerular histiocytosis (6 of 17, 35%), and metritis (6 of 11, 55%) with perivascular inflammation, suggesting hematogenous spread Differentials for these lesions included mouse hepatitis virus, ectromelia virus, spp., and was cultured from liver lesions and subcutaneous abscesses and confirmed with 16S ribosomal RNA sequencing. After completing systematic testing of the environment, failure of the water autoclave cycle was suspected as the cause of the outbreak. To address the situation, individually ventilated racks were sanitized and new breeders were purchased; these actions dramatically reduced infections. The current literature contains few reports of infections in immunocompromised mice, and its typical presentation is torticollis and rolling. infection is a potential differential for subcutaneous abscesses, hepatitis, and splenomegaly in immunocompromised mice. Careful monitoring of sterilization techniques is essential to prevent such infections in a barrier facility.
Topics: Animals; Mice; Abscess; Burkholderia gladioli; Burkholderia Infections; Hepatitis; Mice, Inbred NOD; Mice, SCID
PubMed: 38087404
DOI: 10.30802/AALAS-CM-23-000016 -
Cell Reports Aug 2023Immune responses differ between females and males, although such sex-based variance is incompletely understood. Observing that bacteremia of the opportunistic pathogen...
Immune responses differ between females and males, although such sex-based variance is incompletely understood. Observing that bacteremia of the opportunistic pathogen Burkholderia gladioli caused many more deaths of female than male mice bearing genetic deficiencies in adaptive immunity, we determined that this was associated with sex bias in the innate immune memory response called trained immunity. Female attenuation of trained immunity varies with estrous cycle stage and correlates with serum progesterone, a hormone that decreases glycolytic capacity and recall cytokine secretion induced by antigen non-specific stimuli. Progesterone receptor antagonism rescues female trained immune responses and survival from controlled B. gladioli infection to magnitudes similar to those of males. These data demonstrate progesterone-dependent sex bias in trained immunity where attenuation of female responses is associated with survival outcomes from opportunistic infection.
Topics: Female; Male; Animals; Mice; Progesterone; Sexism; Trained Immunity; Opportunistic Infections; Adaptive Immunity
PubMed: 37590139
DOI: 10.1016/j.celrep.2023.113007 -
Foods (Basel, Switzerland) Jan 2024pv. is a serious safety issue in black fungus due to the deadly toxin, bongkrekic acid. This has triggered the demand for an efficient toxigenic phenotype recognition...
pv. is a serious safety issue in black fungus due to the deadly toxin, bongkrekic acid. This has triggered the demand for an efficient toxigenic phenotype recognition method. The objective of this study is to develop an efficient method for the recognition of toxin-producing strains. The potential of multilocus sequence typing and a back propagation neural network for the recognition of toxigenic was explored for the first time. The virulent strains were isolated from a black fungus cultivation environment in Qinba Mountain area, Shaanxi, China. A comprehensive evaluation of toxigenic capability of 26 isolates were conducted using Ultra Performance Liquid Chromatography for determination of bongkrekic acid and toxoflavin production in different culturing conditions and foods. The isolates produced bongkrekic acid in the range of 0.05-6.24 mg/L in black fungus and a highly toxin-producing strain generated 201.86 mg/L bongkrekic acid and 45.26 mg/L toxoflavin in co-cultivation with on PDA medium. Multilocus sequence typing phylogeny (MLST) analysis showed that housekeeping gene sequences have a certain relationship with a strain toxigenic phenotype. We developed a well-trained, back-propagation neutral network for prediction of toxigenic phenotype in based on MLST sequences with an accuracy of 100% in the training set and an accuracy of 86.7% in external test set strains. The BP neutral network offers a highly efficient approach to predict toxigenic phenotype of strains and contributes to hazard detection and safety surveillance.
PubMed: 38275718
DOI: 10.3390/foods13020351 -
Microbiology Spectrum Jun 2023Burkholderia gladioli strain NGJ1 exhibits mycophagous activity on a broad range of fungi, including Rhizoctonia solani, a devastating plant pathogen. Here, we...
Burkholderia gladioli strain NGJ1 exhibits mycophagous activity on a broad range of fungi, including Rhizoctonia solani, a devastating plant pathogen. Here, we demonstrate that the nicotinic acid (NA) catabolic pathway in NGJ1 is required for mycophagy. NGJ1 is auxotrophic to NA and it potentially senses R. solani as a NA source. Mutation in the and genes involved in NA catabolism renders defects in mycophagy and the mutant bacteria are unable to utilize R. solani extract as the sole nutrient source. As supplementation of NA, but not FA (fumaric acid, the end product of NA catabolism) restores the mycophagous ability of ΔΔ mutants, we anticipate that NA is not required as a carbon source for the bacterium during mycophagy. Notably, , a MarR-type of transcriptional regulator that functions as a negative regulator of the NA catabolic pathway is upregulated in Δ/Δ mutant and upon NA supplementation the expression is reduced to the basal level in both the mutants. The Δ mutant produces excessive biofilm and is completely defective in swimming motility. On the other hand, Δ/Δ mutants are compromised in swimming motility as well as biofilm formation, potentially due to the upregulation of . Our data suggest that a defect in NA catabolism alters the NA pool in the bacterium and upregulates which in turn suppresses bacterial motility as well as biofilm formation, leading to mycophagy defects. Mycophagy is an important trait through which certain bacteria forage over fungal mycelia and utilize fungal biomass as a nutrient source to thrive in hostile environments. The present study emphasizes that nicotinic acid (NA) is important for bacterial motility and biofilm formation during mycophagy by Burkholderia gladioli strain NGJ1. Defects in NA catabolism potentially alter the cellular NA pool, upregulate the expression of , a negative regulator of biofilm, and therefore suppress bacterial motility as well as biofilm formation, leading to mycophagy defects.
Topics: Burkholderia gladioli; Niacin; Bacteria; Biofilms; Mutation; Bacterial Proteins; Gene Expression Regulation, Bacterial
PubMed: 37014254
DOI: 10.1128/spectrum.04457-22 -
Molecules (Basel, Switzerland) Oct 2023Glutarimide-containing polyketides exhibiting potent antitumor and antimicrobial activities were encoded via conserved module blocks in various strains that favor the...
Glutarimide-containing polyketides exhibiting potent antitumor and antimicrobial activities were encoded via conserved module blocks in various strains that favor the genomic mining of these family compounds. The bioinformatic analysis of the genome of ATCC 10248 showed a silent -AT PKS biosynthetic gene cluster (BGC) on chromosome 2 (Chr2C8), which was predicted to produce new glutarimide-containing derivatives. Then, the silent polyketide synthase gene cluster was successfully activated via in situ promoter insertion and heterologous expression. As a result, seven glutarimide-containing analogs, including five new ones, gladiofungins D-H (-), and two known gladiofungin A/gladiostatin () and (named gladiofungin C), were isolated from the fermentation of the activated mutant. Their structures were elucidated through the analysis of HR-ESI-MS and NMR spectroscopy. The structural diversities of gladiofungins may be due to the degradation of the butenolide group in gladiofungin A () during the fermentation and extraction process. Bioactivity screening showed that and had moderate anti-inflammatory activities. Thus, genome mining combined with promoter engineering and heterologous expression were proved to be effective strategies for the pathway-specific activation of the silent BGCs for the directional discovery of new natural products.
Topics: Burkholderia gladioli; Polyketides; Piperidones; Genomics; Multigene Family
PubMed: 37836780
DOI: 10.3390/molecules28196937 -
Frontiers in Microbiology 2023Extensive crop losses are caused by oomycete and fungal damping-off diseases. Agriculture relies heavily on chemical pesticides to control disease, but due to safety...
Extensive crop losses are caused by oomycete and fungal damping-off diseases. Agriculture relies heavily on chemical pesticides to control disease, but due to safety concerns multiple agents have been withdrawn. were successfully used as commercial biopesticides because of their fungicidal activity and plant protective traits. However, their potential for opportunistic pathogenicity led to a moratorium on their registration as biopesticides. Subsequently, were shown to produce multiple specialised metabolites including potent antimicrobial polyynes. Cepacin A, a polyyne produced by biopesticide strains was shown to be an important metabolite for the protection of germinating peas against (formerly ) damping-off disease. Recently, there has been an expansion in bacterial polyyne discovery, with the metabolites and their biosynthetic gene pathways found in several bacterial genera including , , , and . To define the efficacy of these bacterial polyyne producers as biopesticidal agents, we systematically evaluated metabolite production, microbial antagonism, and biocontrol across a panel of 30 strains representing four bacterial genera. polyyne production and antimicrobial activity was demonstrated for most strains, but only polyyne producers were protective within the damping-off pea protection model. was the most effective cepacin-expressing biopesticide, and despite their known potential for plant pathogenicity and were uniquely shown to be protective as caryoynencin-producing biopesticides. In summary, are effective biopesticides due to their suite of antimicrobials, but the ability to deploy polyyne metabolites, caryoynencin and cepacin, is strain and species dependent. Graphical Abstract.
PubMed: 37692405
DOI: 10.3389/fmicb.2023.1240206 -
Plant Disease May 2023Bacterial panicle blight (BPB) has become one of the most destructive diseases of rice worldwide and and are two major pathogens causing BPB (1). This disease causes...
Bacterial panicle blight (BPB) has become one of the most destructive diseases of rice worldwide and and are two major pathogens causing BPB (1). This disease causes several types of damage, most importantly grain spotting, rot, and panicle blight, which can result in yield losses of 75% or more (1,3). In recent years, symptoms including sheath rot, grain spotting, grain rot, and panicle blight have been observed in both inbred and hybrid rice varieties. These symptoms resemble those of BPB and cause cultivar-dependent yield losses. (3) also reported the same symptoms for BPB. To confirm the cause of the disease, 21 rice panicles (Haridhan, a local variety) with typical BPB symptoms were collected from a farmer's field in the region of Mymensingh, Bangladesh during the rainy season in mid-October, 2021. Due to the severity of the outbreak, the panicles became dark brown and produced chaffy grains; nearly 100% of the rice panicles in that field were severely infected. To identify the causal pathogen(s), 1g of rice grains from 20 plants with typical BPB symptoms were surface-sterilized by immersing them in 70% ethanol for a few seconds followed by sodium hypochlorite solution (3%) for 1min. The grains were then rinsed with sterilized distilled water three times. Surface-sterilized grains were then ground with a mortar and pestle; 5mL of sterile distilled water was added during grinding. The extracted suspension (20µL) was then either streaked or spread onto the selective medium (S-PG) (2). Bacterial colonies showing purple color on the S-PG medium were selected and purified as candidate pathogens. For molecular characterization, species specific primers targeting gene were used to perform PCR and resulted in 479bp as reported by (4). To verify further, the PCR products of 16SF & 16SR were amplified and sequenced partially producing around 1400bp (1) and five 16SF partial sequences were deposited into NCBI GenBank (OP108276 to OP108280). 16S rDNA and revealed almost 99% homology with (KU851248.1, MZ425424.1) and (AB220893, CP033430) respectively using BLAST analysis. These purified bacterial isolates produced a diffusible light-yellow pigment on King's B medium indicating toxoflavin production (3). The candidate five bacterial isolates were then confirmed by inoculating 10ml suspension 10CFU/mL into the panicles and sheaths of BRRIdhan28 in net house condition as described previously (1). All of the bacterial isolates obtained from the spotted rice grains produced light brown lesions on the inoculated leaf sheath as well as spotting on the grain. To fulfill Koch's postulates, the bacteria were re-isolated from the symptomatic panicles and were confirmed as by analyzing the sequences of and 16s rDNA genes. Taken together, these results confirmed that is responsible for causing BPB in the rice grain samples that we collected. To our knowledge, this is the first report of BPB caused by in Bangladesh and further research is necessary to develop an effective disease management technique, or else the production of rice will be severely hampered.
PubMed: 37221243
DOI: 10.1094/PDIS-02-23-0229-PDN -
Antimicrobial Agents and Chemotherapy Nov 2023The novel clinical-stage β-lactam-β-lactamase inhibitor combination, cefepime-taniborbactam, demonstrates promising activity toward many Gram-negative bacteria...
The novel clinical-stage β-lactam-β-lactamase inhibitor combination, cefepime-taniborbactam, demonstrates promising activity toward many Gram-negative bacteria producing class A, B, C, and/or D β-lactamases. We tested this combination against a panel of 150 complex (Bcc) and strains. The addition of taniborbactam to cefepime shifted cefepime minimum inhibitory concentrations toward the provisionally susceptible range in 59% of the isolates tested. Therefore, cefepime-taniborbactam possessed similar activity as first-line agents, ceftazidime and trimethoprim-sulfamethoxazole, supporting further development.
Topics: Humans; United States; Cefepime; Anti-Bacterial Agents; Burkholderia gladioli; Burkholderia cepacia complex; Cystic Fibrosis; beta-Lactamase Inhibitors; beta-Lactamases; Microbial Sensitivity Tests
PubMed: 37768313
DOI: 10.1128/aac.00498-23 -
Molecular Plant-microbe Interactions :... Mar 2024Burkholderia gladioli pv. alliicola, B.cepacia, and B. orbicola are common bacterial pathogens of onion. Onions produce organosulfur thiosulfinate defensive compounds...
Burkholderia gladioli pv. alliicola, B.cepacia, and B. orbicola are common bacterial pathogens of onion. Onions produce organosulfur thiosulfinate defensive compounds after cellular decompartmentalization. Using whole genome sequencing and in silico analysis, we identified putative thiosulfinate tolerance gene (TTG) clusters in multiple onion-associated Burkholderia species similar to those characterized in other Allium-associated bacterial endophytes and pathogens. Sequence analysis revealed the presence of three Burkholderia TTG cluster types with both Type A and Type B being broadly distributed in B. gladioli, B. cepacia, and B. orbicola in both the chromosome and plasmids. Based on isolate natural variation and generation of isogenic strains, we determined the in vitro and in vivo contribution of TTG clusters in B. gladioli, B. cepacia, and B. orbicola. The Burkholderia TTG clusters contributed to enhanced allicin tolerance and improved growth in filtered onion extract by all three species. TTG clusters also made clear contributions to B. gladioli foliar necrosis symptoms and bacterial populations. Surprisingly, the TTG cluster did not contribute to bacterial populations in onion bulb scales by these three species. Based on our findings, we hypothesize onion-associated Burkholderia may evade or inhibit the production of thiosulfinates in onion bulb tissues.
PubMed: 38489400
DOI: 10.1094/MPMI-01-24-0005-R