The cereus matter of Bacillus endophthalmitis

Mursalin, Huzzatul; Livingston, Erin; Callegan, Michelle C.

doi:10.1016/j.exer.2020.107959

Cited by 41 publications

(62 citation statements)

References 265 publications

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“…B. thuringiensis 407 (WT) or its isogenic InhA mutants (ΔinhA1, ΔinhA2, ΔinhA1-3) [35,64] were injected into mouse eyes, as previously described [2,6,21,23,26,65,[65][66][67].…”

Section: Bacterial Strainsmentioning

confidence: 99%

“…Strains were diluted in fresh BHI to approximately 10 CFU/mL and incubated for an additional 10 hours. Every 2 hours, 20-μL aliquots were track diluted in PBS and plated onto BHI agar plates, and counted after 24 hours [2,6,21,23,26,65,[65][66][67]. Values are expressed in percent hemolysis relative to a 100% lysis control, as previously described [16,19,26,61,68].Values represent the means ± SD of two independent experiments.…”

Section: Bacterial Growth Curvesmentioning

confidence: 99%

“…Harvested eyes were homogenized in 400 μL PBS containing sterile glass beads (1 mm; BioSpec Products, Inc., Bartlesville, OK, USA). Eye homogenates were then track diluted onto BHI agar and counted, as previously described [2,6,21,23,26,65,[65][66][67].…”

Section: Quantifying Intraocular Bacterial Growthmentioning

confidence: 99%

“…One of the most severe forms of intraocular inflammation and rapid vision loss caused by bacteria is due to infection with Bacillus spp. [1][2][3][4][5][6]. Bacillus endophthalmitis occurs most often following ocular trauma involving a foreign body contaminated with this bacterium [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…ERG was used to quantify retinal function in eyes infected with WT or ΔinhA B. thuringiensis, as previously described[2,6,21,23,26,65,[65][66][67]. Scotopic ERGs were performed at 6, 8, 10, 12, 14, and 16 hours postinfection using Espion E2 software (Diagnosys LLC, Lowell, MA, USA).…”

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confidence: 99%

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Immune Inhibitor A Metalloproteases Contribute to Virulence inBacillusEndophthalmitis

Livingston

Mursalin

Coburn

et al. 2020

Preprint

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AbstractBacterial endophthalmitis is a devastating infection that can cause blindness following the introduction of organisms into the posterior segment of the eye. Over half of Bacillus endophthalmitis cases result in significant loss of useful vision. Often, these eyes have to be enucleated. Bacillus produces many virulence factors in the eye that may contribute to retinal damage and robust inflammation. This study analyzed Bacillus immune inhibitor A (InhA) metalloproteases, which digest extracellular matrix, tight junction proteins, and antimicrobial proteins. We hypothesized that InhAs contribute to Bacillus intraocular virulence and inflammation. We analyzed phenotypes and infectivity of wild type (WT), InhA1-deficient (ΔinhA1), InhA2-deficient (ΔinhA2), or InhA1, A2, and A3-deficient (ΔinhA1-3) Bacillus thuringiensis. In vitro analysis of growth, proteolysis, and cytotoxicity were compared between B. thuringiensis strains. WT and InhA mutants were similarly cytotoxic to retinal cells. Mutant ΔinhA1 and ΔinhA2 entered log phase growth earlier than WT. Proteolysis of the ΔinhA1-3 mutant was decreased, but this strain grew similar to WT in vitro. Experimental endophthalmitis was initiated by intravitreally infecting C57BL/6J mice with 200 CFU of B. thuringiensis WT or InhA mutants. Intraocular Bacillus and retinal function loss were quantified. Intraocular myeloperoxidase concentrations were quantified and histology was analyzed. Eyes infected with ΔinhA1 or ΔinhA2 strains contained greater numbers of bacteria than eyes infected with WT throughout the course of infection. Eyes infected with single mutants had inflammation and retinal function loss similar to eyes infected with WT strain. Eyes infected with ΔinhA1-3 cleared the infection, with less retinal function loss and inflammation compared to eyes infected with the WT strain. RT-PCR results suggested that single InhA mutant results may be explained by compensatory expression of the other InhAs in these mutants. These results indicate that together, the InhA metalloproteases contribute to the severity of infection and inflammation in Bacillus endophthalmitis.Author summaryBacterial endophthalmitis is an infection of the eye, which can follow accidental contamination of the posterior segment following ocular surgery (postoperative), a penetrating wound (post-traumatic), or during spread of bacteria into the eye from the bloodstream (endogenous). During bacterial endophthalmitis, virulent pathogens such as Bacillus cause ocular damage via the activities of an array of virulence factors, including proteases. A class of proteases that are expressed by Bacillus during ocular infection are the immune inhibitor A metalloproteases. Here, we used a mouse model of endophthalmitis to test mutant Bacillus that lack single or multiple InhAs to determine if these metalloproteases contributed to the virulence during the disease. In the absence of the production of all InhAs, Bacillus could not cause severe infection. Our study provides new insights into the virulence of Bacillus in the eye, and the contribution of its InhA metalloproteases to establishing infection.

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“…B. thuringiensis 407 (WT) or its isogenic InhA mutants (ΔinhA1, ΔinhA2, ΔinhA1-3) [35,64] were injected into mouse eyes, as previously described [2,6,21,23,26,65,[65][66][67].…”

Section: Bacterial Strainsmentioning

confidence: 99%

Section: Bacterial Growth Curvesmentioning

confidence: 99%

Section: Quantifying Intraocular Bacterial Growthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Immune Inhibitor A Metalloproteases Contribute to Virulence inBacillusEndophthalmitis

Livingston

Mursalin

Coburn

et al. 2020

Preprint

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Ocular microbiota types and longitudinal microbiota alterations in patients with chronic dacryocystitis with and without antibiotic pretreatment

Wu,

Zhu,

Wang

et al. 2024

iMetaOmics

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Antibiotic pretreatment is routine for chronic dacryocystitis (DC) patients. Herein, the longitudinal effects of antibiotic pretreatment before dacryocystorhinostomy for DC patients were evaluated. Conjunctival and nasal swabs were collected longitudinally from 33 DC patients with and without antibiotic pretreatment, both before dacryocystorhinostomy and at 1, 2, and 4 weeks postdacryocystorhinostomy. Additionally, conjunctival sac swabs were collected from 46 healthy volunteers and 14 other ocular diseases patients. Comparisons focused on ocular/nasal microbiota and recovery outcomes. Compared to healthy participants, DC patients without antibiotic pretreatment exhibited greater ocular microbiota diversity before dacryocystorhinostomy. Although clinical recovery rates were comparable, our results suggest that, after antibiotic pretreatment, the ocular microbiota richness and diversity, and the composition alteration tendency, significantly changed 4 weeks after surgery. This implies that the ocular microbiota was more disturbed in patients who underwent antibiotic pretreatment compared to those without such treatment. Furthermore, two types of ocular microbiota and three types of nasal microbiota were identified in ocular diseases. This study provides comprehensive data on the ocular and nasal microbiota in DC patients with and without antibiotic pretreatment, along with other ocular diseases. This finding suggested that antibiotic pretreatment may not be necessary before dacryocystorhinostomy for DC patients, especially for nonsevere cases.

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Endophthalmitis Following Ocular Trauma in Armed Conflicts

Gupta¹

2023

Ocular Trauma in Armed Conflicts

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The cereus matter of Bacillus endophthalmitis

Cited by 41 publications

References 265 publications

Immune Inhibitor A Metalloproteases Contribute to Virulence inBacillusEndophthalmitis

Immune Inhibitor A Metalloproteases Contribute to Virulence inBacillusEndophthalmitis

Ocular microbiota types and longitudinal microbiota alterations in patients with chronic dacryocystitis with and without antibiotic pretreatment

Endophthalmitis Following Ocular Trauma in Armed Conflicts

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