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Epicatechin gallate, a naturally occurring polyphenol, alters the course of infection with β-lactam-resistant Staphylococcus aureus in the zebrafish embryo.

Stevens CS, Rosado H, Harvey RJ, Taylor PW - Front Microbiol (2015)

Bottom Line: No significant increases in survival were noted when infected embryos were maintained in medium containing 12.5-100 μg/mL ECg with or without 4 or 16 μg/mL oxacillin.However, when EMRSA-16 was grown in medium containing 12.5 μg/mL ECg and the bacteria used to infect embryos by either the circulation valley or yolk sac, there were significant increases in embryo survival in both the presence and absence of oxacillin.We conclude that exposure to ECg prior to infection reduces the lethality of EMRSA-16, renders cells more susceptible to elimination by immune processes and compromises their capacity to establish an inflammatory response in comparison to non-exposed bacteria.

View Article: PubMed Central - PubMed

Affiliation: UCL School of Pharmacy, University College London London, UK.

ABSTRACT
(-)-epicatechin gallate (ECg) substantially modifies the properties of Staphylococcus aureus and reversibly abrogates β-lactam resistance in methicillin/oxacillin resistant (MRSA) isolates. We have determined the capacity of ECg to alter the course of infection in zebrafish embryos challenged with epidemic clinical isolate EMRSA-16. At 30 h post fertilization (hpf), embryos were infected by injection of 1-5 × 10(3) colony forming units (CFU) of EMRSA-16 into the circulation valley or yolk sac. Infection by yolk sac injection was lethal with a challenge dose above 3 × 10(3) CFU, with no survivors at 70 hpf. In contrast, survival at 70 hpf after injection into the circulation was 83 and 44% following challenge with 3 × 10(3) and 1-5 × 10(3) CFU, respectively. No significant increases in survival were noted when infected embryos were maintained in medium containing 12.5-100 μg/mL ECg with or without 4 or 16 μg/mL oxacillin. However, when EMRSA-16 was grown in medium containing 12.5 μg/mL ECg and the bacteria used to infect embryos by either the circulation valley or yolk sac, there were significant increases in embryo survival in both the presence and absence of oxacillin. ECg-modified and unmodified, GFP-transformed EMRSA-16 bacteria were visualized within phagocytic cells in the circulation and yolk sac; pre-treatment with ECg also significantly increased induction of the respiratory burst and suppressed increases in IL-1β expression typical of infection with untreated EMRSA-16. We conclude that exposure to ECg prior to infection reduces the lethality of EMRSA-16, renders cells more susceptible to elimination by immune processes and compromises their capacity to establish an inflammatory response in comparison to non-exposed bacteria.

No MeSH data available.


Related in: MedlinePlus

Survival of zebrafish embryos following injection into the circulation valley (A) or yolk sac (B) at 30 hpf with 3 × 103 EMRSA-16 bacteria modified in vitro by growth in 12.5 μg/mL ECg and incubation in antibiotic-free E3 medium or E3 medium containing 4 μg/mL oxacillin. n = 23–24 per group; differences between ECg-modified and unmodified bacteria were significant for both injection sites P < 0.001 (log rank test).
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Figure 3: Survival of zebrafish embryos following injection into the circulation valley (A) or yolk sac (B) at 30 hpf with 3 × 103 EMRSA-16 bacteria modified in vitro by growth in 12.5 μg/mL ECg and incubation in antibiotic-free E3 medium or E3 medium containing 4 μg/mL oxacillin. n = 23–24 per group; differences between ECg-modified and unmodified bacteria were significant for both injection sites P < 0.001 (log rank test).

Mentions: To obtain evidence that MRSA cells modified by exposure to ECg are impaired with regard to their capacity to cause lethal infection, we grew EMRSA-16 to mid-logarithmic phase in MH broth supplemented with 12.5 μg/mL ECg and infected 30 hpf embryos by the circulation valley (Figure 3A) or yolk sac (Figure 3B) with 3 × 103 CFU of ECg-modified bacteria; infected embryos were then incubated in E3 medium with and without oxacillin (4 μg/mL) supplementation. For both injection sites, ECg-modified bacteria were significantly less virulent than EMRSA-16 cells that were not exposed to ECg prior to administration. Incubation with oxacillin after infection had no impact of survival (circulation: P = 0.5627; yolk: P = 0.6129; log rank test).


Epicatechin gallate, a naturally occurring polyphenol, alters the course of infection with β-lactam-resistant Staphylococcus aureus in the zebrafish embryo.

Stevens CS, Rosado H, Harvey RJ, Taylor PW - Front Microbiol (2015)

Survival of zebrafish embryos following injection into the circulation valley (A) or yolk sac (B) at 30 hpf with 3 × 103 EMRSA-16 bacteria modified in vitro by growth in 12.5 μg/mL ECg and incubation in antibiotic-free E3 medium or E3 medium containing 4 μg/mL oxacillin. n = 23–24 per group; differences between ECg-modified and unmodified bacteria were significant for both injection sites P < 0.001 (log rank test).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585009&req=5

Figure 3: Survival of zebrafish embryos following injection into the circulation valley (A) or yolk sac (B) at 30 hpf with 3 × 103 EMRSA-16 bacteria modified in vitro by growth in 12.5 μg/mL ECg and incubation in antibiotic-free E3 medium or E3 medium containing 4 μg/mL oxacillin. n = 23–24 per group; differences between ECg-modified and unmodified bacteria were significant for both injection sites P < 0.001 (log rank test).
Mentions: To obtain evidence that MRSA cells modified by exposure to ECg are impaired with regard to their capacity to cause lethal infection, we grew EMRSA-16 to mid-logarithmic phase in MH broth supplemented with 12.5 μg/mL ECg and infected 30 hpf embryos by the circulation valley (Figure 3A) or yolk sac (Figure 3B) with 3 × 103 CFU of ECg-modified bacteria; infected embryos were then incubated in E3 medium with and without oxacillin (4 μg/mL) supplementation. For both injection sites, ECg-modified bacteria were significantly less virulent than EMRSA-16 cells that were not exposed to ECg prior to administration. Incubation with oxacillin after infection had no impact of survival (circulation: P = 0.5627; yolk: P = 0.6129; log rank test).

Bottom Line: No significant increases in survival were noted when infected embryos were maintained in medium containing 12.5-100 μg/mL ECg with or without 4 or 16 μg/mL oxacillin.However, when EMRSA-16 was grown in medium containing 12.5 μg/mL ECg and the bacteria used to infect embryos by either the circulation valley or yolk sac, there were significant increases in embryo survival in both the presence and absence of oxacillin.We conclude that exposure to ECg prior to infection reduces the lethality of EMRSA-16, renders cells more susceptible to elimination by immune processes and compromises their capacity to establish an inflammatory response in comparison to non-exposed bacteria.

View Article: PubMed Central - PubMed

Affiliation: UCL School of Pharmacy, University College London London, UK.

ABSTRACT
(-)-epicatechin gallate (ECg) substantially modifies the properties of Staphylococcus aureus and reversibly abrogates β-lactam resistance in methicillin/oxacillin resistant (MRSA) isolates. We have determined the capacity of ECg to alter the course of infection in zebrafish embryos challenged with epidemic clinical isolate EMRSA-16. At 30 h post fertilization (hpf), embryos were infected by injection of 1-5 × 10(3) colony forming units (CFU) of EMRSA-16 into the circulation valley or yolk sac. Infection by yolk sac injection was lethal with a challenge dose above 3 × 10(3) CFU, with no survivors at 70 hpf. In contrast, survival at 70 hpf after injection into the circulation was 83 and 44% following challenge with 3 × 10(3) and 1-5 × 10(3) CFU, respectively. No significant increases in survival were noted when infected embryos were maintained in medium containing 12.5-100 μg/mL ECg with or without 4 or 16 μg/mL oxacillin. However, when EMRSA-16 was grown in medium containing 12.5 μg/mL ECg and the bacteria used to infect embryos by either the circulation valley or yolk sac, there were significant increases in embryo survival in both the presence and absence of oxacillin. ECg-modified and unmodified, GFP-transformed EMRSA-16 bacteria were visualized within phagocytic cells in the circulation and yolk sac; pre-treatment with ECg also significantly increased induction of the respiratory burst and suppressed increases in IL-1β expression typical of infection with untreated EMRSA-16. We conclude that exposure to ECg prior to infection reduces the lethality of EMRSA-16, renders cells more susceptible to elimination by immune processes and compromises their capacity to establish an inflammatory response in comparison to non-exposed bacteria.

No MeSH data available.


Related in: MedlinePlus