A medium for enriching Listeria spp. without polymerase chain reaction (PCR) inhibition and a method of using the medium.
1. An enrichment medium for enhancing growth of Listeria a spp., the medium comprising, per 1 L of water, about 10 to about 40 g of tryptic soy broth, about 1 to about 10 g of yeast extract, about 1 to about 10 g of lithium chloride, about 1 to about 5 g of pyruvate or a salt thereof, about 4 g of MOPS free acid, about 7.1 g of sodium MOPS, about 1 to about 10 mg of acriflavine, about 5 to about 15 mg of polymyxin B, about 10 to about 30 mg of ceftazidime, about 0.01 to about 1 g of ferric ammonium citrate, and about 1 to about 10 g of beef extract.
2. The medium of claim 1 , wherein the medium does not comprise esculin.
3. The medium of claim 1 , comprising, per 1 L of water, about 30 g of tryptic soy broth, about 6 g of yeast extract, about 1 to about 10 g of lithium chloride, about 5 g of beef extract, about 2 g of sodium pyruvate, about 0.2 g of ferric ammonium citrate, about 4 g of MOPS free acid, about 7.1 g of sodium MOPS, about 5 mg of acriflavine, about 10 mg of polymyxin B, and about 20 mg of ceftazidime.
4. A method of enriching Listeria spp. in a sample, the method comprising culturing the sample including Listeria spp, in a medium comprising, per 1 L of water:
about 10 to about 40 g of tryptic soy broth, about 1 to about 10 g of yeast extract, about 1 to about 10 g of lithium chloride, about 1 to about 5 g of pyruvate or a salt thereof, about 0.01 to about 1 g of ferric ammonium citrate, about 1 to about 10 g of beef extract, about 4 g of MOPS free acid, about 7.1 g of sodium MOPS, about 1 to about 10 mg of acriflavine, about 5 to about 15 mg of polymyxin B, and about 10 to about 30 mg of ceftazidime.
5. The method of claim 4 , wherein the medium does not comprise esculin.
6. The medium of claim 4 , wherein the medium comprises, per 1 L of water, about 30 g of tryptic soy broth; about 6 g of yeast extract; about 1 to about 10 g of lithium chloride; about 5 g of beef extract; about 2 g of sodium pyruvate; about 0.2 g of ferric ammonium citrate; about 4 g of MOPS free acid; about 7.1 g of sodium MOPS; about 5 mg of acriflavine; about 10 mg of polymyxin B; and about 20 mg of ceftazidime.
7. The medium of claim 1 , wherein the medium further comprises a vitamin mix containing about 0.01 to about 0.5 mg of riboflavine, about 0.5 to about 1.5 mg of thiamine, and about 0.01 to about 1.5 mg of biotin.
8. The method of claim 4 , wherein the medium further comprises a vitamin mix containing about 0.01 to about 0.5 mg of riboflavine, about 0.5 to about 1.5 mg of thiamine, and about 0.01 to about 1.5 mg of biotin.