|Jung, Yong Soo|
|Genovese, Kenneth - Ken|
Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2003
Publication Date: N/A
Technical Abstract: The bactericidal effect of 2-nitropropanol (2NPOH), a nitroalkane, on several pathogenic bacteria including Salmonella enterica subsp. serovar Typhimurium, Escherichia coli O157:H7, Listeria innocua, and Enterococcus faecalis was determined in vitro. The test compound was added to tryptic soy broth (TSB) medium in amounts to give 0, 2.5, 5, and 10 mM final concentration. Specific growth rates (h-1) (n=3) were calculated by measuring optical density (A600). The growth of gram negative (Typhimurium and E. coli O157:H7) and positive (L. innocua and E. faecalis) was largely prohibited at greater than or equal 2.5 mM 2NPOH and was completely inhibited at 10 mM 2NPOH. To determine if pH affected the bactericidal activity of 2NPOH, approximately 10**5 to 10**6 CFU per ml of Typhimurium were inoculated into TSB medium containing 0, 2.5, and 10 mM of 2NPOH and adjusted to 5.6, 7.2, and 8.0. After 24 h incubation at 37 deg C, cell numbers were reduced approximately 3 log (from 10**5 to 10**2 CFU/ml) at 2.5 mM 2NPOH at pH 5.6 but not at 7.2 or 8.0. However, Typhimurium was completely inactivated (> 5 log reductions) at 10 mM 2NPOH regardless of pH. To evaluate the bactericidal effect of 2NPOH against Typhimurium in buffered rumen and fecal fluid (pH 6.8), a novobiocin and nalidixic acid resistant Typhimurium strain was inoculated into these mixtures supplemented with 0, 2.5, 10 mM 2NPOH and incubated at 37 deg C under CO2. The populations were monitored at different times (0, 3, 6, and 24 h). After 24 h, mean +/- SD populations (log CFU/ml) of Typhimurium were reduced significantly (P < 0.05) in both ruminal and fecal fluid containing 2NPOH at 10 mM concentration compared to controls (0.55 +/- 0.64 vs 2.65 +/- 0.06 and 0.1 +/- 0.00 vs 2.80 +/- 0.28, respectively). The results obtained in this study indicate that 2NPOH has bactericidal activity against Salmonella, E. coli O157:H7, L. innocua, and E. faecalis, and potentially could be developed as an antimicrobial supplement.