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Table 2 Antagonism of catecholamine-induced growth responsiveness

From: Blockade of catecholamine-induced growth by adrenergic and dopaminergic receptor antagonists in Escherichia coli O157:H7, Salmonella enterica and Yersinia enterocolitica

   Antagonist Concentration (μM)
Species Antagonist CA 0 0.1 1 10 20 50 75 100 200 bN/A
E. coli O157:H7 Phentolamine NE a 8.29 8.23 8.04 7.75 7.48 6.65 5.88 5.74 5.69 4.14
   NE+Fe c 8.30         8.19  
   Epi 8.20 8.12 8.21 8.01 7.88 7.32 6.46 5.94 5.84  
   Epi+Fe 8.19         8.04  
   Dop 8.16 8.11 8.12 8.16 8.00 7.92 7.83 7.78 7.69  
  Phenoxybenzamine NE 8.25 8.13 8.12 7.62 7.47 6.90 5.51 4.26 4.00 4.34
   NE+Fe 8.19         8.05  
   Epi 8.13 8.09 8.00 8.02 7.76 7.00 6.46 5.90 5.81  
   Epi+Fe 8.20         8.04  
   Dop 8.16 8.16 8.15 8.11 8.12 8.10 8.00 7.99 7.87  
  Prazosin NE 8.25 8.25 8.03 8.00 7.78 7.31 6.72 5.85 5.47 4.16
   NE+Fe 8.27         8.28  
   Epi 8.12 8.16 8.13 8.08 7.94 7.81 6.43 6.12 5.66  
   Epi+Fe 8.16         8.10  
   Dop 8.13 8.12 8.11 8.09 8.12 8.10 8.08 8.04 8.00  
  Propranolol NE 8.14 8.07 8.08 8.00 8.08 8.03 8.00 7.99 7.90 4.16
   Epi 8.13 8.11 8.14 8.10 8.21 8.12 8.13 8.08 7.88  
   Dop 8.15 8.15 8.10 8.10 8.07 8.06 8.03 8.06 8.07  
S. enterica Phentolamine NE 8.25 8.25 8.00 7.94 6.94 6.83 5.83 5.80 5.50 4.88
   Epi 8.07 8.04 8.01 7.93 7.61 6.90 5.66 5.07 4.68  
   Dop 8.09 8.07 8.05 8.12 8.12 8.04 7.99 7.82 7.34  
  Phenoxybenzamine NE 8.27 8.23 8.20 8.14 7.90 6.62 6.41 6.34 5.18 4.89
   Epi 8.15 8.14 8.17 8.16 7.87 7.04 6.94 6.77 5.97  
   Dop 8.10 8.11 8.10 8.07 8.09 8.07 8.04 8.01 8.00  
  Prazosin NE 8.17 8.16 8.10 8.04 7.74 7.48 6.94 5.41 5.00 4.87
   Epi 8.14 8.14 8.16 8.14 8.10 7.82 7.33 6.95 6.77  
   Dop 8.12 8.15 8.12 8.10 8.12 8.07 7.07 8.03 8.05  
  Propranolol NE 8.15 8.14 8.10 8.07 8.19 8.16 8.06 7.98 7.75 4.89
   Epi 8.18 8.19 8.15 8.08 8.16 8.08 8.08 8.03 8.01  
   Dop 8.16 8.09 8.12 8.14 8.10 8.09 8.12 8.06 8.05  
Y. enterocolitica Phentolamine NE 8.30 8.29 8.26 7.96 7.54 6.87 6.52 5.99 5.99 3.83
   Dop 8.11 8.06 8.11 8.08 8.11 8.08 8.07 8.03 8.01  
  Phenoxybenzamine NE 8.28 8.32 8.23 7.86 7.00 6.81 6.26 5.77 5.62 3.90
   Dop 8.09 8.07 8.11 8.10 8.08 8.07 6.10 8.03 7.99  
  Prazosin NE 8.25 8.21 8.15 8.03 7.47 6.95 6.64 6.50 5.88 3.82
   Dop 8.05 8.07 8.08 8.07 8.08 8.06 8.04 8.01 7.94  
  Propranolol NE 8.26 8.22 8.24 8.20 8.19 8.22 8.07 8.04 7.99 4.00
   Dop 8.05 8.08 8.09 8.11 8.12 8.07 8.08 8.03 8.04  
  1. E. coli O157:H7, S. enterica and Y. enterocolitica were inoculated at approximately 102 CFU/ml into duplicate 1 mL aliquots of serum-SAPI containing the catecholamines (CA) NE, Epi and Dop plus the concentrations of antagonists shown in the table, and incubated for either 18 hours (E. coli and S. enterica) or 40 hours (Y. enterocolitica), and enumerated for growth (a, expressed as log-10 CFU/ml) as described in Materials and Methods. Growth levels of non-catecholamine supplemented cultures (b, N/A) are shown for comparison purposes. NE and Dop were used at 50 μM, and Epi and Fe (Fe(NO3)3) at 100 μM. Note that catecholamine antagonist assays containing Fe (c) were also performed for S. enterica and Y. enterocolitica and confirmed, by no effect on bacterial growth induction by iron, that the antagonists were not toxic (data not shown). The results shown are representative data from at least three separate experiments; all data points showed variation of less than 5%. Antagonist supplemented cultures showed statistically significant decreases in growth levels (P < 0.001) as compared with control (catecholamine only supplemented) cultures.