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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 at 30 h post fertilization (hpf) with EMRSA-16 bacteria into the circulation valley (A) or yolk sac (B).n = 21 ± 1 in each group for (A), n = 22 ± 2 for (B). The number of bacteria injected in a volume of 1–2 nl ranged from 1 × 103 to 5 × 103 colony forming unit (CFU), as indicated. The staphylococcal bioburden in embryos infected by the circulation valley at 30 hpf with 5 × 103 CFU is shown in (C) and by the yolk sac with 2 × 103 CFU in (D). n = 60 for each group.
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Figure 1: Survival of zebrafish embryos following injection at 30 h post fertilization (hpf) with EMRSA-16 bacteria into the circulation valley (A) or yolk sac (B).n = 21 ± 1 in each group for (A), n = 22 ± 2 for (B). The number of bacteria injected in a volume of 1–2 nl ranged from 1 × 103 to 5 × 103 colony forming unit (CFU), as indicated. The staphylococcal bioburden in embryos infected by the circulation valley at 30 hpf with 5 × 103 CFU is shown in (C) and by the yolk sac with 2 × 103 CFU in (D). n = 60 for each group.

Mentions: EMRSA-16 cells were injected into the yolk sac and circulation valley at 30 hpf, as established by Prajsnar et al. (2008). Survival of embryos infected by the circulation valley was directly related to the number of injected bacteria (Figure 1A) as determined by product limit estimation (Kaplan and Meier, 1958). Death occurred earlier in embryos infected with 3 × 103 and 5 × 103 CFU of EMRSA-16 than in embryos infected with 1 × 103 and 2 × 103 CFU. At 70 hpi 95% of embryos infected with1 × 103 CFU survived, compared with 87% infected with 2 × 103, 83% with 3 × 103 and 44% with 5 × 103 CFU. All embryos injected with the same volume of 0.05% phenol red in PBS or heat-killed EMRSA-16 survived (data not shown). A similar trend was evident when EMRSA-16 was injected into the yolk, with survival decreasing in a dose-dependent manner (Figure 1B). Deaths were recorded in each infected group at 17 hpi and a subsequent decrease in survival at each time point was observed. A substantial decrease in survival was detected at 43 hpi in embryos infected with 2 × 103, 3 × 103, and 5 × 103 CFU. After 70 hpi, 54% of embryos infected with 1 × 103 and 50% with 2 × 103 CFU survived. However, no embryos survived in the groups infected with 3 × 103 or 5 × 103 CFU.


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 at 30 h post fertilization (hpf) with EMRSA-16 bacteria into the circulation valley (A) or yolk sac (B).n = 21 ± 1 in each group for (A), n = 22 ± 2 for (B). The number of bacteria injected in a volume of 1–2 nl ranged from 1 × 103 to 5 × 103 colony forming unit (CFU), as indicated. The staphylococcal bioburden in embryos infected by the circulation valley at 30 hpf with 5 × 103 CFU is shown in (C) and by the yolk sac with 2 × 103 CFU in (D). n = 60 for each group.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Survival of zebrafish embryos following injection at 30 h post fertilization (hpf) with EMRSA-16 bacteria into the circulation valley (A) or yolk sac (B).n = 21 ± 1 in each group for (A), n = 22 ± 2 for (B). The number of bacteria injected in a volume of 1–2 nl ranged from 1 × 103 to 5 × 103 colony forming unit (CFU), as indicated. The staphylococcal bioburden in embryos infected by the circulation valley at 30 hpf with 5 × 103 CFU is shown in (C) and by the yolk sac with 2 × 103 CFU in (D). n = 60 for each group.
Mentions: EMRSA-16 cells were injected into the yolk sac and circulation valley at 30 hpf, as established by Prajsnar et al. (2008). Survival of embryos infected by the circulation valley was directly related to the number of injected bacteria (Figure 1A) as determined by product limit estimation (Kaplan and Meier, 1958). Death occurred earlier in embryos infected with 3 × 103 and 5 × 103 CFU of EMRSA-16 than in embryos infected with 1 × 103 and 2 × 103 CFU. At 70 hpi 95% of embryos infected with1 × 103 CFU survived, compared with 87% infected with 2 × 103, 83% with 3 × 103 and 44% with 5 × 103 CFU. All embryos injected with the same volume of 0.05% phenol red in PBS or heat-killed EMRSA-16 survived (data not shown). A similar trend was evident when EMRSA-16 was injected into the yolk, with survival decreasing in a dose-dependent manner (Figure 1B). Deaths were recorded in each infected group at 17 hpi and a subsequent decrease in survival at each time point was observed. A substantial decrease in survival was detected at 43 hpi in embryos infected with 2 × 103, 3 × 103, and 5 × 103 CFU. After 70 hpi, 54% of embryos infected with 1 × 103 and 50% with 2 × 103 CFU survived. However, no embryos survived in the groups infected with 3 × 103 or 5 × 103 CFU.

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