Similarly Lethal Strains of Extraintestinal Pathogenic Escherichia coli Trigger Markedly Diverse Host Responses in a Zebrafish Model of Sepsis

Barber, Amelia E.; Fleming, Brittany A.; Mulvey, Matthew A.

doi:10.1128/msphere.00062-16

Cited by 26 publications

(20 citation statements)

References 106 publications

(109 reference statements)

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“…The results revealed that out of 25 E. coli isolates, 10 isolates were oehemolytic, 2 isolates were ß-hemolytic, and 13 isolates were gamma hemolytic representing 40%, 8%, and 52% respectively. Our results agree with those reported elsewhere [16,17] where they found a large proportion of human extraintestinal E. coli isolates produce hemolysin representing (35-50%) and (35-60%) respectively, relative to normal fecal isolates (10%). Also they mentioned that epidemiological evidence indicates a role for alpha-hemolysin in extraintestinal human infections.…”

Section: Identification Of E Coli Isolatessupporting

confidence: 93%

Determination the site of antibiotic resistance genes in Escherichia coli isolated From Urinary Tract Infection

Mohammad

Ahmed

Mohammed

et al. 2018

KJAR

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This study includes isolation of 25 isolates of Escherichia coli (E. coli ) strain from urinary tract samples in a pregnant woman. Microbiological and biochemical tests were used to identify the resistant bacteria of this genus. Screening methods were used to determine bacterial isolates for their resistance to 10 antibiotics include: Amikacin (Ak), Amoxicillin (Ax), Ampicillin (Ap), Chloramphenicol (Cm), Ciprofloxacin (Cip), Erythromycin (Er), Nalidixic acid (Nal), Penicillin (Pen), Tetracycline (Tet) and Trimethoprim (Tm). The isolates E4, E9, E16, and E17 were resistant to all antibiotics used in the current study using the disk diffusion method. In contrast, the resistance percentage for all antibiotics ranged between 28-96%. Sites of resistance genes and hemolysin production genes were characterized by tranformation techniques in the E4 and E16. The results showed that the antibiotic resistance genes of Amikacin, Erythromycin, Tetracyclin, and Trimethoprim were located on a plasmid, whereas Amoxicillin, Ampicillin, Chloramphenicol, Ciprofloxacin, Nalidixic acid and Penicillin were located on chromosomal DNA. The results also demonstrated an inability to produce alpha or beta-hemolysin indicating that the genes which are responsible for hemolysin production were also located on chromosomal DNA.

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Section: Identification Of E Coli Isolatessupporting

confidence: 93%

Determination the site of antibiotic resistance genes in Escherichia coli isolated From Urinary Tract Infection

Mohammad

Ahmed

Mohammed

et al. 2018

KJAR

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“…We injected approximately 2,500 colony-forming units (CFU) of trimethoprim-resistant E . coli into the pericardial cavity of zebrafish embryos [ 75 , 78 ], incubated for 3 hours, then treated with either the original drug combination (trimethoprim + sulfamethizole) or our rationally designed combination (floxuridine + AZT). We analyzed bacterial burden at 24 hours postinoculation (hpi) at dosages analogous to human dosage (see Materials and methods and Table 4 ) [ 79 , 80 ].…”

Section: Resultsmentioning

confidence: 99%

“…coli blood isolates #1–8 (referred to as BEC1, BEC2, etc.) are described in Barber et al [ 78 ]. Urinary tract infection (UTI) isolates and K .…”

Section: Methodsmentioning

confidence: 99%

High-throughput identification and rational design of synergistic small-molecule pairs for combating and bypassing antibiotic resistance

et al. 2017

Self Cite

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Antibiotic-resistant infections kill approximately 23,000 people and cost $20,000,000,000 each year in the United States alone despite the widespread use of small-molecule antimicrobial combination therapy. Antibiotic combinations typically have an additive effect: the efficacy of the combination matches the sum of the efficacies of each antibiotic when used alone. Small molecules can also act synergistically when the efficacy of the combination is greater than the additive efficacy. However, synergistic combinations are rare and have been historically difficult to identify. High-throughput identification of synergistic pairs is limited by the scale of potential combinations: a modest collection of 1,000 small molecules involves 1 million pairwise combinations. Here, we describe a high-throughput method for rapid identification of synergistic small-molecule pairs, the overlap2 method (O2M). O2M extracts patterns from chemical-genetic datasets, which are created when a collection of mutants is grown in the presence of hundreds of different small molecules, producing a precise set of phenotypes induced by each small molecule across the mutant set. The identification of mutants that show the same phenotype when treated with known synergistic molecules allows us to pinpoint additional molecule combinations that also act synergistically. As a proof of concept, we focus on combinations with the antibiotics trimethoprim and sulfamethizole, which had been standard treatment against urinary tract infections until widespread resistance decreased efficacy. Using O2M, we screened a library of 2,000 small molecules and identified several that synergize with the antibiotic trimethoprim and/or sulfamethizole. The most potent of these synergistic interactions is with the antiviral drug azidothymidine (AZT). We then demonstrate that understanding the molecular mechanism underlying small-molecule synergistic interactions allows the rational design of additional combinations that bypass drug resistance. Trimethoprim and sulfamethizole are both folate biosynthesis inhibitors. We find that this activity disrupts nucleotide homeostasis, which blocks DNA replication in the presence of AZT. Building on these data, we show that other small molecules that disrupt nucleotide homeostasis through other mechanisms (hydroxyurea and floxuridine) also act synergistically with AZT. These novel combinations inhibit the growth and virulence of trimethoprim-resistant clinical Escherichia coli and Klebsiella pneumoniae isolates, suggesting that they may be able to be rapidly advanced into clinical use. In sum, we present a generalizable method to screen for novel synergistic combinations, to identify particular mechanisms resulting in synergy, and to use the mechanistic knowledge to rationally design new combinations that bypass drug resistance.

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“…Infection assay: 1.5 and 3 OD of lab strain E. coli DH5 alpha-RFP were prepared as previously described 30 and injected in the yolk of 2 dpf zebrafish. Each larva was kept separately in a 96 well plate and survival assessed through 7 dpf.…”

Section: Methodsmentioning

confidence: 99%

Syndecan 2 regulates hematopoietic lineages and infection resolution in zebrafish

Lamichhane

Bisgrove

et al. 2020

Preprint

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237 words Main text: 3834 words Number of figures: 5 Number of supplementary figures: 5 Number of supplementary videos: 6 Number of references: 71 Key Points: 1) Syndecan 2 regulates the formation of Hematopoietic Stem/Progenitor Cells, differentiation into hematopoietic populations and the CHT architecture 2) Syndecan 2 mutants are significantly more susceptible to bacterial infection 2 Abstract Syndecan 2 (Sdc2) is a transmembrane cell-surface heparan sulfate proteoglycan (HSPG) that has been implicated in the regulation of cell-cell signaling pathways and cell-matrix interactions.Surprisingly, homozygous recessive maternal zygotic (MZ) sdc2 null mutants in zebrafish appear to have normal development, normal morphology and are viable and fertile in adulthood. Whole transcriptome RNA sequencing, FACS analyses, and imaging of transgenic reporter lines that distinguish specific hematopoietic lineages revealed that sdc2 mutants have defects in the specification and proportions of red blood cells and neutrophils that initiate during embryonic hematopoiesis and likely persist through adulthood. During bacterial infections, MZsdc2 mutants have markedly reduced neutrophil recruitment and significantly higher death rates.Hematopoietic stem/progenitor cell (HSPC) numbers are also significantly reduced in MZsdc2 mutants. In zebrafish, cells that bud off of the ventral region of somites are thought to give rise to the reticular stromal cells of the caudal hematopoietic tissue (CHT) stem cell niche. In MZsdc2 mutants, these budding cells have abberant blebbing morphology associated with widespread apoptosis during induction of HSPCs and with changes in the vascularization and stromal cell structure of the CHT stem cell niche. This suggests that loss of sdc2 disrupts the earliest events of definitive hematopoiesis. Our findings of hematopoietic defects, nascent immune system alterations and inability to resolve infection in sdc2 mutants sets the stage for examining the roles of HSPG genes in a wide range of hematopoietic and immune defects in humans. Fn Fn DAPI DAPI J

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Similarly Lethal Strains of Extraintestinal Pathogenic Escherichia coli Trigger Markedly Diverse Host Responses in a Zebrafish Model of Sepsis

Cited by 26 publications

References 106 publications

Determination the site of antibiotic resistance genes in Escherichia coli isolated From Urinary Tract Infection

Determination the site of antibiotic resistance genes in Escherichia coli isolated From Urinary Tract Infection

High-throughput identification and rational design of synergistic small-molecule pairs for combating and bypassing antibiotic resistance

Syndecan 2 regulates hematopoietic lineages and infection resolution in zebrafish

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