On 2015 Jan 06, Anthony Michael commented:

Polyamine-replete rich growth medium Tryptic Soy Broth (TSB) has been used in this study for all growth and biofilm analyses. TSB contains extract from soybean, a leguminous plant closely related to alfalfa (Medicago sativa). Alfalfa is known to contain norspermidine (Rodriquez-Garay et al., 1989, “Detection of norspermidine and norspermine in Medicago sativa L. (Alfalfa)”, Plant Physiol 89(2): 525-9 Rodriguez-Garay B, 1989). The authors claim that the cell-free supernatant of the Staphylococcus epidermidis cell culture after 40 hours of growth contains self-produced norspermidine at a concentration of 326.7 micromolar. Presumably the conclusion that the norspermidine is self-produced is due to the fact that norspermidine was not detected in the supernatant after 4 hours of growth. However, no molecules were detected in the supernatant after four hours of growth, even though the growth medium is a complex rich medium (Fig. 2C). As no sequenced Staphylococcus species encodes either carboxynorspermidine dehydrogenase and carboxynorspermidine decarboxylase, or S-adenosylmethionine decarboxylase and spermidine synthase to make norspermidine or spermidine, respectively, the claim that S. epidermidis synthesizes norspermidine would be convincing only if the growth and biofilm experiments had been performed with a polyamine-free, chemically-defined growth medium.

On 2015 Jan 06, Anthony Michael commented:

Polyamine-replete rich growth medium Tryptic Soy Broth (TSB) has been used in this study for all growth and biofilm analyses. TSB contains extract from soybean, a leguminous plant closely related to alfalfa (Medicago sativa). Alfalfa is known to contain norspermidine (Rodriquez-Garay et al., 1989, “Detection of norspermidine and norspermine in Medicago sativa L. (Alfalfa)”, Plant Physiol 89(2): 525-9 Rodriguez-Garay B, 1989). The authors claim that the cell-free supernatant of the Staphylococcus epidermidis cell culture after 40 hours of growth contains self-produced norspermidine at a concentration of 326.7 micromolar. Presumably the conclusion that the norspermidine is self-produced is due to the fact that norspermidine was not detected in the supernatant after 4 hours of growth. However, no molecules were detected in the supernatant after four hours of growth, even though the growth medium is a complex rich medium (Fig. 2C). As no sequenced Staphylococcus species encodes either carboxynorspermidine dehydrogenase and carboxynorspermidine decarboxylase, or S-adenosylmethionine decarboxylase and spermidine synthase to make norspermidine or spermidine, respectively, the claim that S. epidermidis synthesizes norspermidine would be convincing only if the growth and biofilm experiments had been performed with a polyamine-free, chemically-defined growth medium.