Eradication of Klebsiella Quasipneumoniae By Eudragit-Formulated Klebicin Kvaria In The Intestinal Tract of Mice

Abstract Background: Klebsiella quasipneumoniae is an opportunistic pathogen causing antibiotic-resistant infections of the gastrointestinal tract in many clinical cases. Orally delivered bioactive Klebsiella-specific antimicrobial proteins, klebicins, could be a promising method to eradicate Klebsiella species infecting the gut.Methods: Mouse infection model wasestablished based on infection of streptomycin treated BALB/C mice with K. quasipneumoniae strain DSM28212. Four study groups were used (3 animals/group) to test the antimicrobial efficacy of orally delivered klebicin KvarIa: vehicle-only group (control, phosphate-buffered saline), and other three groups with bacteria, antibiotic therapy and 100 µg of uncoated Kvarla, 100 µg coated KvarIa, 1000 µg coated-KvarIa. Because of the general sensitivity of bacteriocins to gastroduodenal proteases, Kvarla doses were coated with Eudragit®, a GMP-certified formulation agent that releases the protein at certain pH. The coating treatment was selected based on measurements of mouse GI tract pH. The quantity of Klebsiella haemolysin gene (khe) in faecal samples of the study animals was used to quantify the presence of Klebsiella.Results: GI colonization of K. quasipneumoniae was achieved only in the antibiotic-treated mice groups. Significant changes in khe marker quantification were found after the use of Eudragit® S100 formulated klebicin KvarIa, at both doses, with a significant reduction of K. quasipneumoniae colonization compared to the vehicle-only control group.Conclusions: Mouse GI tract colonization with K. quasipneumoniae can be achieved if natural gut microbiota is suppressed by prior antibiotic treatment. The study demonstrates that GI infection caused by K. quasipneumoniae can be significantly reduced using Eudragit®-protected klebicin KvarIa.

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Eradication of Klebsiella quasipneumoniae by Eudragit-formulated klebicin KvarIa in the intestinal tract of mice

10.21203/rs.3.rs-1075190/v1 ◽

2021 ◽

Author(s):

Indre Karaliute ◽

Rima Ramonaite ◽

Jurga Bernatoniene ◽

Vilma Petrikaite ◽

Audrius Misiunas ◽

...

Keyword(s):

Opportunistic Pathogen ◽

Study Groups ◽

Control Group ◽

Infection Model ◽

Gi Tract ◽

Antimicrobial Proteins ◽

Antibiotic Resistant ◽

Mouse Infection Model ◽

Faecal Samples ◽

Phosphate Buffered Saline

Abstract Background Klebsiella quasipneumoniae is an opportunistic pathogen causing antibiotic-resistant infections of the gastrointestinal tract in many clinical cases. Orally delivered bioactive Klebsiella-specific antimicrobial proteins, klebicins, could be a promising method to eradicate Klebsiella species infecting the gut. Methods Mouse infection model wasestablished based on infection of streptomycin treated BALB/C mice with K. quasipneumoniae strain DSM28212. Four study groups were used (3 animals/group) to test the antimicrobial efficacy of orally delivered klebicin KvarIa: vehicle-only group (control, phosphate-buffered saline), and other three groups with bacteria, antibiotic therapy and 100 µg of uncoated Kvarla, 100 µg coated KvarIa, 1000 µg coated-KvarIa. Because of the general sensitivity of bacteriocins to gastroduodenal proteases, Karla doses were coated with Eudragit®, a GMP-certified formulation agent that releases the protein at certain pH. The coating treatment was selected based on measurements of mouse GI tract pH. The quantity of Klebsiella haemolysin gene (khe) in faecal samples of the study animals was used to quantify the presence of Klebsiella. Results GI colonization of K. quasipneumoniae was achieved only in the antibiotic-treated mice groups. Significant changes in khe marker quantification were found after the use of Eudragit® S100 formulated klebicin KvarIa, at both doses, with a significant reduction of K. quasipneumoniae colonization compared to the vehicle-only control group. Conclusions Mouse GI tract colonization with K. quasipneumoniae can be achieved if natural gut microbiota is suppressed by prior antibiotic treatment. The study demonstrates that GI infection caused by K. quasipneumoniae can be significantly reduced using Eudragit®-protected klebicin KvarIa.

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Toxicity of Povidone-Iodine to the Ocular Surface of Rabbits

10.21203/rs.2.11866/v1 ◽

2019 ◽

Author(s):

Sun Young Kim ◽

Yong Sun Ahn ◽

Yeo Jin Lee ◽

Hyun Seung Kim

Keyword(s):

Ocular Surface ◽

Povidone Iodine ◽

Study Groups ◽

Ultrastructural Changes ◽

Control Group ◽

Dependent Manner ◽

Impression Cytology ◽

Schirmer Test ◽

Phosphate Buffered Saline ◽

Goblet Cell Density

Abstract Background We evaluated the toxicity of 5% (w/v) povidone-iodine (PI) applied to the ocular surface of rabbits. Methods Twenty three white rabbits were divided into four groups; these were a control group and three study groups in which the ocular surface was exposed to PI for different times. In control group, phosphate-buffered saline (PBS) was applied once for 10 minutes. In study groups, 5% (w/v) PI was topically applied once for 1 minute, 3 minutes, and 10 minutes, and then the animals were observed for 7 days. The Schirmer test, Rose Bengal staining, corneal fluorescein staining and conjunctival impression cytology were performed on day 0, 3, and 7. After 7 days, the rabbits were sacrificed and conjunctiva and cornea were collected and evaluated by light and electron microscope. Immunofluorescence staining was also performed to detect mucin 5 subtype AC (MUC5AC). Results The decrease in goblet cell density, reductions in MUC5AC level and histopathological and ultrastructural changes of conjunctiva and cornea were more prominent in the 5% (w/v) PI groups than the control group (p < 0.05). Moreover, these changes were more prominent when PI was applied for 3 and 10 minutes rather than 1 minute (both p values < 0.05). Conclusions 5% (w/v) povidone-iodine caused damages to the ocular surface in a time-dependent manner. Therefore, we should be aware of that excessive PI exposure during ophthalmic procedures could be a pathogenic factor of dry eye syndrome after surgery.

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Global Transcriptional Response to Organic Hydroperoxide and the Role of OhrR in the Control of Virulence Traits in Chromobacterium violaceum

Infection and Immunity ◽

10.1128/iai.00017-17 ◽

2017 ◽

Vol 85 (8) ◽

Cited By ~ 9

Author(s):

Maristela Previato-Mello ◽

Diogo de Abreu Meireles ◽

Luis Eduardo Soares Netto ◽

José Freire da Silva Neto

Keyword(s):

Cumene Hydroperoxide ◽

Transcriptional Response ◽

Transcriptional Regulator ◽

Opportunistic Pathogen ◽

Chromobacterium Violaceum ◽

Infection Model ◽

Diguanylate Cyclase ◽

Major Pathway ◽

Content Type ◽

Mouse Infection Model

ABSTRACT A major pathway for the detoxification of organic hydroperoxides, such as cumene hydroperoxide (CHP), involves the MarR family transcriptional regulator OhrR and the peroxidase OhrA. However, the effect of these peroxides on the global transcriptome and the contribution of the OhrA/OhrR system to bacterial virulence remain poorly explored. Here, we analyzed the transcriptome profiles of Chromobacterium violaceum exposed to CHP and after the deletion of ohrR, and we show that OhrR controls the virulence of this human opportunistic pathogen. DNA microarray and Northern blot analyses of CHP-treated cells revealed the upregulation of genes related to the detoxification of peroxides (antioxidant enzymes and thiol-reducing systems), the degradation of the aromatic moiety of CHP (oxygenases), and protection against other secondary stresses (DNA repair, heat shock, iron limitation, and nitrogen starvation responses). Furthermore, we identified two upregulated genes (ohrA and a putative diguanylate cyclase with a GGDEF domain for cyclic di-GMP [c-di-GMP] synthesis) and three downregulated genes (hemolysin, chitinase, and collagenase) in the ohrR mutant by transcriptome analysis. Importantly, we show that OhrR directly repressed the expression of the putative diguanylate cyclase. Using a mouse infection model, we demonstrate that the ohrR mutant was attenuated for virulence and showed a decreased bacterial burden in the liver. Moreover, an ohrR-diguanylate cyclase double mutant displayed the same virulence as the wild-type strain. In conclusion, we have defined the transcriptional response to CHP, identified potential virulence factors such as diguanylate cyclase as members of the OhrR regulon, and shown that C. violaceum uses the transcriptional regulator OhrR to modulate its virulence.

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Toxicity of Povidone-Iodine to the Ocular Surface of Rabbits

10.21203/rs.2.11866/v4 ◽

2020 ◽

Author(s):

Sun Young Kim ◽

Yong Sun Ahn ◽

Yeo Jin Lee ◽

Hyun Seung Kim

Keyword(s):

Ocular Surface ◽

Povidone Iodine ◽

Study Groups ◽

Ultrastructural Changes ◽

Control Group ◽

Dependent Manner ◽

Impression Cytology ◽

Schirmer Test ◽

Phosphate Buffered Saline ◽

Goblet Cell Density

Abstract Background : We evaluated the toxicity of 5% (w/v) povidone-iodine (PI) applied to the ocular surface of rabbits. Methods: Twenty-three white rabbits were divided into four groups; these were a control group and three study groups in which the ocular surface was exposed to PI for different times. In control group, one drop of phosphate-buffered saline (PBS) was applied once for 10 minutes. In study groups, one drop of 5% (w/v) PI was topically applied once for 1 minute, 3 minutes, and 10 minutes, and then the animals were observed for 7 days. The Schirmer test, Rose Bengal staining, corneal fluorescein staining and conjunctival impression cytology were performed on day 0, 3, and 7. After 7 days, the rabbits were sacrificed and conjunctiva and cornea were collected and evaluated by light and electron microscope. Immunofluorescence staining was also performed to detect mucin 5 subtype AC (MUC5AC). Results: The decrease in goblet cell density, reductions in MUC5AC level and histopathological and ultrastructural changes of conjunctiva and cornea were more prominent in the 5% (w/v) PI groups than the control group ( p < 0.05). Moreover, these changes were more prominent when PI was applied for 3 and 10 minutes rather than 1 minute (both p values < 0.05). Conclusions: 5% (w/v) povidone-iodine caused damages to the ocular surface in a time-dependent manner. Therefore, we should be aware of that excessive PI exposure during ophthalmic procedures could be a pathogenic factor of dry eye syndrome after surgery.

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Development of a Potent Antimicrobial Peptide With Photodynamic Activity

Frontiers in Microbiology ◽

10.3389/fmicb.2021.624465 ◽

2021 ◽

Vol 12 ◽

Author(s):

Di Zhang ◽

Jingyi Chen ◽

Qian Jing ◽

Zheng Chen ◽

Azeem Ullah ◽

...

Keyword(s):

Antimicrobial Peptide ◽

Red Light ◽

Antimicrobial Effect ◽

Resistant Bacteria ◽

Infection Model ◽

Light Illumination ◽

Gram Positive ◽

Antibiotic Resistant ◽

Gram Positive Bacteria ◽

Mouse Infection Model

The emergence of antibiotic-resistant bacteria poses a serious challenge to medical practice worldwide. A small peptide with sequence RWRWRW was previously identified as a core antimicrobial peptide with limited antimicrobial spectrum to bacteria, especially Gram-positive bacteria. By conjugating this peptide and its analogs with lipophilic phthalocyanine (Pc), we identified a new antibiotic peptide [PcG3K5(RW)3]. The peptide demonstrates increased antimicrobial effect to both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. In addition, Pc also provides added and potent antimicrobial effect upon red light illumination. The inhibitory efficacy of PcG3K5(RW)3 was increased by ~140-fold to nanomolar range upon illumination. Moreover, PcG3K5(RW)3 was safe for mammalian cell and promoted wound healing in the mouse infection model. Our work provides a new direction to optimize antimicrobial peptides to enhance antimicrobial efficacy.

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Toxicity of Povidone-Iodine to the Ocular Surface of Rabbits

10.21203/rs.2.11866/v5 ◽

2020 ◽

Author(s):

Sun Young Kim ◽

Yong Sun Ahn ◽

Yeo Jin Lee ◽

Hyun Seung Kim

Keyword(s):

Ocular Surface ◽

Povidone Iodine ◽

Study Groups ◽

Ultrastructural Changes ◽

Control Group ◽

Dependent Manner ◽

Impression Cytology ◽

Schirmer Test ◽

Phosphate Buffered Saline ◽

Goblet Cell Density

Abstract Background: We evaluated the toxicity of 5% (w/v) povidone-iodine (PI) applied to the ocular surface of rabbits.Methods: Twenty-three white rabbits were divided into four groups; these were a control group and three study groups in which the ocular surface was exposed to PI for different times. In control group, one drop of phosphate-buffered saline (PBS) was applied once for 10 minutes. In study groups, one drop of 5% (w/v) PI was topically applied once for 1 minute, 3 minutes, and 10 minutes, and then the animals were observed for 7 days. The Schirmer test, Rose Bengal staining, corneal fluorescein staining and conjunctival impression cytology were performed on day 0, 3, and 7. After 7 days, the rabbits were sacrificed and conjunctiva and cornea were collected and evaluated by light and electron microscope. Immunofluorescence staining was also performed to detect mucin 5 subtype AC (MUC5AC).Results: The decrease in goblet cell density, reductions in MUC5AC level and histopathological and ultrastructural changes of conjunctiva and cornea were more prominent in the 5% (w/v) PI groups than the control group (p < 0.05). Moreover, these changes were more prominent when PI was applied for 3 and 10 minutes rather than 1 minute (both p values < 0.05).Conclusions: 5% (w/v) povidone-iodine caused damages to the ocular surface in a time-dependent manner. Therefore, we should be aware of that excessive PI exposure during ophthalmic procedures could be a pathogenic factor of dry eye syndrome after surgery.

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Toxicity of Povidone-Iodine to the Ocular Surface of Rabbits

10.21203/rs.2.11866/v3 ◽

2019 ◽

Author(s):

Sun Young Kim ◽

Yong Sun Ahn ◽

Yeo Jin Lee ◽

Hyun Seung Kim

Keyword(s):

Ocular Surface ◽

Povidone Iodine ◽

Study Groups ◽

Ultrastructural Changes ◽

Control Group ◽

Dependent Manner ◽

Impression Cytology ◽

Schirmer Test ◽

Phosphate Buffered Saline ◽

Goblet Cell Density

Abstract Background: We evaluated the toxicity of 5% (w/v) povidone-iodine (PI) applied to the ocular surface of rabbits. Methods: Twenty-three white rabbits were divided into four groups; these were a control group and three study groups in which the ocular surface was exposed to PI for different times. In control group, one drop of phosphate-buffered saline (PBS) was applied once for 10 minutes. In study groups, one drop of 5% (w/v) PI was topically applied once for 1 minute, 3 minutes, and 10 minutes, and then the animals were observed for 7 days. The Schirmer test, Rose Bengal staining, corneal fluorescein staining and conjunctival impression cytology were performed on day 0, 3, and 7. After 7 days, the rabbits were sacrificed and conjunctiva and cornea were collected and evaluated by light and electron microscope. Immunofluorescence staining was also performed to detect mucin 5 subtype AC (MUC5AC). Results: The decrease in goblet cell density, reductions in MUC5AC level and histopathological and ultrastructural changes of conjunctiva and cornea were more prominent in the 5% (w/v) PI groups than the control group (p < 0.05). Moreover, these changes were more prominent when PI was applied for 3 and 10 minutes rather than 1 minute (both p values < 0.05). Conclusions: 5% (w/v) povidone-iodine caused damages to the ocular surface in a time-dependent manner. Therefore, we should be aware of that excessive PI exposure during ophthalmic procedures could be a pathogenic factor of dry eye syndrome after surgery.

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Semisynthetic glycopeptide antibiotics derived from LY264826 active against vancomycin-resistant enterococci.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.9.2194 ◽

1996 ◽

Vol 40 (9) ◽

pp. 2194-2199 ◽

Cited By ~ 82

Author(s):

T I Nicas ◽

D L Mullen ◽

J E Flokowitsch ◽

D A Preston ◽

N J Snyder ◽

...

Keyword(s):

In Vivo Studies ◽

Infection Model ◽

Glycopeptide Antibiotics ◽

Coagulase Negative Staphylococci ◽

Antibiotic Resistant ◽

Methicillin Resistant ◽

Mouse Infection Model ◽

Highly Active ◽

Vancomycin Resistant

Certain derivatives of the glycopeptide antibiotic LY264826 with N-alkyl-linked substitutions on the epivancosamine sugar are active against glycopeptide-resistant enterococci. Six compounds representing our most active series were evaluated for activity against antibiotic-resistant, gram-positive pathogens. For Enterococcus faecium and E. faecalis resistant to both vancomycin and teicoplanin, the MICs of the six semisynthetic compounds for 90% of the strains tested were 1 to 4 micrograms/ml, compared with 2,048 micrograms/ml for vancomycin and 256 micrograms/ml for LY264826. For E. faecium and E. faecalis resistant to vancomycin but not teicoplanin, the MICs were 0.016 to 1 micrograms/ml, compared with 64 to 1,024 micrograms/ml for vancomycin. The compounds were highly active against vancomycin-susceptible enterococci and against E. gallinarum and E. casseliflavus and showed some activity against isolates of highly vancomycin-resistant leuconostocs and pediococci. The MICs for 90% of the strains of methicillin-resistant Staphylococcus aureus tested were typically 0.25 to 1 micrograms/ml, compared with 1 microgram/ml for vancomycin. Against methicillin-resistant S. epidermidis MICs ranged from 0.25 to 2 micrograms/ml, compared with 1 to 4 micrograms/ml for vancomycin and 4 to 16 micrograms/ml for teicoplanin. The spectrum of these new compounds included activity against teicoplanin-resistant, coagulase-negative staphylococci. The compounds exhibited exceptional potency against pathogenic streptococci, with MICs of < or = 0.008 microgram/ml against Streptococcus pneumoniae, including penicillin-resistant isolates. In in vivo studies with a mouse infection model, the median effective doses against a challenge by S. aureus, S. pneumoniae, or S. pyogenes were typically 4 to 20 times lower than those of vancomycin. Overall, these new glycopeptides, such as LY307599 and LY333328, show promise for use as agents against resistant enterococci, methicillin-resistant S. aureus, and penicillin-resistant pneumococci.

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Toxicity of Povidone-Iodine to the Ocular Surface of Rabbits

10.21203/rs.2.11866/v2 ◽

2019 ◽

Author(s):

Sun Young Kim ◽

Yong Sun Ahn ◽

Yeo Jin Lee ◽

Hyun Seung Kim

Keyword(s):

Ocular Surface ◽

Povidone Iodine ◽

Study Groups ◽

Ultrastructural Changes ◽

Control Group ◽

Dependent Manner ◽

Impression Cytology ◽

Schirmer Test ◽

Phosphate Buffered Saline ◽

Goblet Cell Density

Abstract Background: We evaluated the toxicity of 5% (w/v) povidone-iodine (PI) applied to the ocular surface of rabbits. Methods: Twenty-three white rabbits were divided into four groups; these were a control group and three study groups in which the ocular surface was exposed to PI for different times. In control group, one drop of phosphate-buffered saline (PBS) was applied once for 10 minutes. In study groups, one drop of 5% (w/v) PI was topically applied once for 1 minute, 3 minutes, and 10 minutes, and then the animals were observed for 7 days. The Schirmer test, Rose Bengal staining, corneal fluorescein staining and conjunctival impression cytology were performed on day 0, 3, and 7. After 7 days, the rabbits were sacrificed and conjunctiva and cornea were collected and evaluated by light and electron microscope. Immunofluorescence staining was also performed to detect mucin 5 subtype AC (MUC5AC). Results: The decrease in goblet cell density, reductions in MUC5AC level and histopathological and ultrastructural changes of conjunctiva and cornea were more prominent in the 5% (w/v) PI groups than the control group (p < 0.05). Moreover, these changes were more prominent when PI was applied for 3 and 10 minutes rather than 1 minute (both p values < 0.05). Conclusions: 5% (w/v) povidone-iodine caused damages to the ocular surface in a time-dependent manner. Therefore, we should be aware of that excessive PI exposure during ophthalmic procedures could be a pathogenic factor of dry eye syndrome after surgery.

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Antibacterial activity of self-adhesive resin cements against Streptococcus mutans at different time intervals

Iranian Journal of Microbiology ◽

10.18502/ijm.v11i4.1469 ◽

2019 ◽

Cited By ~ 2

Author(s):

Amir-Ahmad Ajami ◽

Sahand Rikhtegaran ◽

Mahmoud Bahari ◽

Sayeh Hamadanchi

Keyword(s):

Antibacterial Activity ◽

Streptococcus Mutans ◽

Study Groups ◽

Control Group ◽

Acidic Property ◽

Resin Cements ◽

Time Intervals ◽

Adhesive Resin ◽

The Mean ◽

Phosphate Buffered Saline

Background and Objectives: Self-adhesive resin cements release fluoride and have cytotoxic and preventive monomers against the bacteria in their composition. They have acidic property before their complete setting too. The antibacterial ac- tivity of three different self-adhesive resin cements against Streptococcus mutans at different time intervals was investigated in this study. Materials and Methods: The modified direct contact test was used to evaluate the antibacterial effect of Max-Cem, G-Cem and Bis-Cem on S. mutans after aging the samples in phosphate-buffered saline solution for one hour, 24 hours and 1 week. Data were analyzed using one-way ANOVA, repeated measurement ANOVA and Tukey HSD tests (P<0.05). Results: The differences in the mean bacterial counts between all the study groups and between the study groups and the corresponding control groups were significant at 1-hour and 24-hour intervals (P<0.001). At 1-week, only the differenc- es between Bis-Cem and G-Cem, between Max-Cem and Bis-Cem, and between Bis-Cem and the corresponding control group were significant (P<0.001). There were significant differences between G-Cem and Max-Cem at all the time intervals (P<0.001). In addition, with the use of Bis-Cem there were significant differences between 1-hour and 1-week (P=0.01) and 24-hour and 1-week (P<0.001). Conclusion: All the cements exhibited antibacterial activity after 1 hour and 24 hours. However, after 1 week, only Bis-Cem retained its antibacterial activity.

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