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Antimicrobial Agents and Chemotherapy Jan 2023Burkholderia cepacia complex (Bcc) and Burkholderia gladioli are opportunistic human pathogens that are inherently multidrug resistant, limiting treatment options for...
Burkholderia cepacia complex (Bcc) and Burkholderia gladioli are opportunistic human pathogens that are inherently multidrug resistant, limiting treatment options for infections. Here, a novel diazabicyclooctane, ETX0462, was evaluated for activity against Bcc and . . Ninety-eight percent of the isolates examined in this study were susceptible. ETX0462 was found to demonstrate activity superior to that of currently available treatment options (e.g., trimethoprim-sulfamethoxazole and ceftazidime).
Topics: Humans; Burkholderia; Anti-Bacterial Agents; Ceftazidime; Trimethoprim, Sulfamethoxazole Drug Combination; Burkholderia cepacia complex; Burkholderia Infections
PubMed: 36507667
DOI: 10.1128/aac.01352-22 -
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 -
Molecular Plant Pathology Jan 2016Burkholderia gladioli is a causal agent of bacterial panicle blight and sheath/grain browning in rice in many countries. Many strains produce the yellow pigment...
Burkholderia gladioli is a causal agent of bacterial panicle blight and sheath/grain browning in rice in many countries. Many strains produce the yellow pigment toxoflavin, which is highly toxic to plants, fungi, animals and microorganisms. Although there have been several studies on the toxoflavin biosynthesis system of B. glumae, it is still unclear how B. gladioli activates toxoflavin biosynthesis. In this study, we explored the genomic organization of the toxoflavin system of B. gladioli and its biological functions using comparative genomic analysis between toxoflavin-producing strains (B. glumae BGR1 and B. gladioli BSR3) and a strain not producing toxoflavin (B. gladioli KACC11889). The latter exhibits normal physiological characteristics similar to other B. gladioli strains. Burkholderia gladioli KACC11889 possesses all the genes involved in toxoflavin biosynthesis, but lacks the quorum-sensing (QS) system that functions as an on/off switch for toxoflavin biosynthesis. These data suggest that B. gladioli has evolved to use the QS signalling cascade of toxoflavin production (TofI/TofR of QS → ToxJ or ToxR → tox operons) similar to that in B. glumae. However, some strains may have evolved to eliminate toxoflavin production through deletion of the QS genes. In addition, we demonstrate that the toxoflavin biosynthetic system enhances the virulence of B. gladioli. These findings provide another line of evidence supporting the differential regulation of the toxoflavin system in Burkholderia strains.
Topics: Biosynthetic Pathways; Burkholderia gladioli; Genes, Bacterial; Genetic Complementation Test; Movement; Onions; Operon; Pyrimidinones; Reproducibility of Results; Triazines; Virulence
PubMed: 25845410
DOI: 10.1111/mpp.12262 -
Frontiers in Plant Science 2023Plant pathogens are one of the major constraints on worldwide food production. The antibiotic properties of microbes identified as effective in managing plant pathogens...
INTRODUCTION
Plant pathogens are one of the major constraints on worldwide food production. The antibiotic properties of microbes identified as effective in managing plant pathogens are well documented.
METHODS
Here, we used antagonism experiments and untargeted metabolomics to isolate the potentially antifungal molecules produced by KJ-34.
RESULTS
KJ-34 is a potential biocontrol bacterium isolated from the rhizosphere soil of rice and can fight multiple fungal pathogens (i.e. ). The favoured fermentation conditions are determined and the fermentation broth treatment can significantly inhibit the infection of and . The fermentation broth suppression ratio is 75% and 82%, respectively. Fermentation broth treatment disrupted the spore germination and led to malformation of hyphae. Additionally, we found that the molecular weight of antifungal products were less than 1000 Da through semipermeable membranes on solid medium assay. To search the potentially antifungal molecules that produce by KJ-34, we used comparative and bioinformatics analyses of fermentation broth before and after optimization by mass spectrometry. Untargeted metabolomics analyses are presumed to have a library of antifungal agents including benzoylstaurosporine, morellin and scopolamine.
DISCUSSION
These results suggest that KJ-34 produced various biological control agents to suppress multiple phytopathogenic fungi and showed a strong potential in the ecological technologies of prevention and protection.
PubMed: 36938063
DOI: 10.3389/fpls.2023.1097044 -
Journal of Clinical Microbiology Aug 2019In persons with cystic fibrosis (CF), airway infection with complex (Bcc) species or presents a significant challenge due to inherent resistance to multiple...
In persons with cystic fibrosis (CF), airway infection with complex (Bcc) species or presents a significant challenge due to inherent resistance to multiple antibiotics. Two chromosomally encoded inducible β-lactamases, a Pen-like class A and AmpC are produced in Bcc and Previously, ceftazidime-avibactam demonstrated significant potency against Bcc and isolated from the sputum of individuals with CF; however, 10% of the isolates tested resistant to ceftazidime-avibactam. Here, we describe an alternative antibiotic combination to overcome ceftazidime-avibactam resistance. Antimicrobial susceptibility testing was performed on Bcc and clinical and control isolates. Biochemical analysis was conducted on purified PenA1 and AmpC1 β-lactamases from ATCC 17616. Analytic isoelectric focusing and immunoblotting were conducted on cellular extracts of induced by various β-lactams or β-lactam-β-lactamase inhibitor combinations. Combinations of piperacillin-avibactam, as well as piperacillin-tazobactam plus ceftazidime-avibactam (the clinically available counterpart), were tested against a panel of ceftazidime-avibactam nonsusceptible Bcc and The piperacillin-avibactam and piperacillin-tazobactam-ceftazidime-avibactam combinations restored susceptibility to 99% of the isolates tested. Avibactam is a potent inhibitor of PenA1 (apparent inhibitory constant [] = 0.5 μM), while piperacillin was found to inhibit AmpC1 ( = 2.6 μM). Moreover, piperacillin, tazobactam, ceftazidime, and avibactam, as well as combinations thereof, did not induce expression of and in the ATCC 17616 background. When ceftazidime-avibactam is combined with piperacillin-tazobactam, the susceptibility of Bcc and to ceftazidime and piperacillin is restored Both the lack of induction and potent inactivation of PenA1 by avibactam likely provide the major contributions toward susceptibility. With validation, piperacillin-tazobactam-ceftazidime-avibactam may represent salvage therapy for individuals with CF and highly drug-resistant Bcc and infections.
Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Burkholderia Infections; Burkholderia cepacia complex; Burkholderia gladioli; Cystic Fibrosis; Drug Resistance, Multiple, Bacterial; Drug Substitution; Humans; Kinetics; Microbial Sensitivity Tests; Piperacillin
PubMed: 31167848
DOI: 10.1128/JCM.00181-19 -
Microorganisms Jun 2022Bacterial panicle blight of rice or bacterial grain rot of rice is a worldwide rice disease. and are the causal agents. The early and accurate detection of seed-borne...
Bacterial panicle blight of rice or bacterial grain rot of rice is a worldwide rice disease. and are the causal agents. The early and accurate detection of seed-borne and is critical for domestic and international quarantine and effective control of the disease. Here, genomic analyses revealed that contains five phylogroups and the BG1 primer pair designed to target the 3'-end sequence of a gene encoding a Rhs family protein is specific to and two phylogroups within . Using the BG1 primer pair, a 138-bp DNA fragment was amplified only from the tested panicle blight pathogens and . An EvaGreen droplet digital PCR (dPCR) assay on detection and quantification of the two pathogens was developed from a SYBR Green real-time quantitative PCR (qPCR). The detection limits of the EvaGreen droplet dPCR on the two pathogens were identical at 2 × 10 colony forming units (CFU)∙mL from bacterial suspensions and 2 × 10 CFU∙seed from rice seeds. The EvaGreen droplet dPCR assay showed 10-fold detection sensitivity of the SYBR Green qPCR and could detect a single copy of the target gene in a 20-μL assay. Together, the SYBR Green qPCR assay allows for routine high-throughput detection of the panicle blight pathogens and the EvaGreen droplet dPCR assay provides a high-sensitive and high-accurate diagnostic method for quarantine of the pathogens.
PubMed: 35744741
DOI: 10.3390/microorganisms10061223 -
Microorganisms May 2021has high versatility and adaptability to various ecological niches. Here, we constructed a pan-genome using 14 genome sequences of , which originate from different...
has high versatility and adaptability to various ecological niches. Here, we constructed a pan-genome using 14 genome sequences of , which originate from different niches, including gladiolus, rice, humans, and nature. Functional roles of core and niche-associated genomes were investigated by pathway enrichment analyses. Consequently, we inferred the uniquely important role of niche-associated genomes in (1) selenium availability during competition with gladiolus host; (2) aromatic compound degradation in seed-borne and crude oil-accumulated environments, and (3) stress-induced DNA repair system/recombination in the cystic fibrosis-niche. We also identified the conservation of the rhizomide biosynthetic gene cluster in all the strains and the concentrated distribution of this cluster in human isolates. It was confirmed the absence of complete CRISPR/Cas system in both plant and human pathogenic and the presence of the system in living in nature, possibly reflecting the inverse relationship between CRISPR/Cas system and virulence.
PubMed: 34067383
DOI: 10.3390/microorganisms9061123 -
Plant Disease Jun 2022Rice (Oryza sativa) is a staple food for most of the world's populations, particularly in Asia (Gumma et al. 2011). The rice sector provides Malaysians with a food...
Rice (Oryza sativa) is a staple food for most of the world's populations, particularly in Asia (Gumma et al. 2011). The rice sector provides Malaysians with a food supply, food sufficiency, and income for growers (Man et al. 2009). From January to February 2022, panicle samples showing symptoms of bacterial panicle blight (BPB) disease, including reddish-brown, linear lesions with indistinct margins on flag-leaf sheaths and blighted, upright, grayish straw-colored florets with sterile and aborted grains on panicles were collected in granary areas in Sekinchan, Selangor, Malaysia with 90% disease incidence in fields. Surface-sterilization of infected leaf tissue was performed using 75% ethanol and 1% sodium hypochlorite, followed by rinsing three times in sterilized water. Leaf tissue was macerated in sterilized water and aliquots were spread on King's B agar medium, then cultured for 24 h to 48 h at 35 °C. All isolated bacteria were Gram-negative rods, positive for catalase and gelatinase but negative for indole, oxidase and hydrogen sulfide (H2S), and utilized sucrose, inositol, mannitol, glucose, and citrate. Colonies were circular and smooth-margined, producing a diffusible yellowish-green pigment on King's B agar medium, which are characteristics of Burkholderia species (Keith et al. 2005). Five representative isolates (UPMBG7, UPMBG8, UPMBG9, UPMBG15, UPMBG17) were selected for molecular and pathogenicity tests. PCR using specific primers targeting the gyrB gene for molecular characterization was performed, and the ∼470 bp amplicons were sequenced (Maeda et al. 2006) and deposited in GenBank (OM824438 to OM824442). A BLASTn analysis revealed that the five isolates were 99% identical to the B. gladioli reference strains MAFF 302533, GRBB15041, and LMG19584 in GenBank (AB190628, KX638432, and AB220898). A phylogenetic tree using Maximum-likelihood analysis of the gyrB gene sequences showed that the five isolates were 99% identical to B. gladioli reference strains (AB190628, KX638432, and AB220898). To verify the identification of these isolates, the 16S rDNA gene was amplified using 16SF/16SR primers (Ramachandran et al. 2021), producing ~1,400 bp amplicons. The resulting sequences of the five isolates (OM869953 to OM869957) were 98% identical to the reference strains of B. gladioli (NR113629 and NR117553). To confirm pathogenicity, 10 ml suspensions of the five isolates at of 108 CFU/ml were inoculated into the panicles and crowns of 75-day-old rice seedlings of local rice varieties MR269 and MR219 grown in a glasshouse with temperatures ranging from 37 °C to 41 °C (Nandakumar et al. 2009). Control rice seedlings were inoculated with sterilized water. All isolates produced BPB disease symptoms like those originally found in the rice fields at four weeks after inoculation. Control seedlings remained asymptomatic. To fulfill Koch's postulates, the bacteria were reisolated from symptomatic panicles and were confirmed as B. gladioli by sequence analysis of the gyrB and 16S rDNA genes. To our knowledge, this is the first report of B. gladioli causing BPB disease of rice in Malaysia. Since BPB disease causes a significant threat to the rice industry, it is crucial to investigate the diversity of this destructive pathogen for effective disease management strategies in Malaysia.
PubMed: 35748735
DOI: 10.1094/PDIS-03-22-0650-PDN -
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 -
Microbiology Resource Announcements Feb 2021is a Gram-negative bacterium associated with cystic fibrosis infections. Here, we describe the genome sequence of phage Maja. Maja is most related to another phage,...
is a Gram-negative bacterium associated with cystic fibrosis infections. Here, we describe the genome sequence of phage Maja. Maja is most related to another phage, BcepF1, and may be a temperate phage, despite the absence of repressor or integrase homologs in its genome sequence.
PubMed: 33541882
DOI: 10.1128/MRA.01430-20