Sixty selected isolates showed a positive results for Api20E and CHROM agar as Klebsiella pneumoniae. primary screening by using minimal salt media  appeared only six isolates have the ability to produce dark brown to black  pigment  in different levels.In vitro melanization assays showed K. pneumoniae HM produces brown colored pigment within 3 days on agar plate containing L-tyrosine. After optimization study, the results showed, the suitable condition for pathogenic Klebsiella pneumoniae HM to produce pigment were L-tyrosine foundation, pH 7.2, with temperature 35^áµ’C, therefore a pilot study was done in flasks, and the results appeared Klebsiella pneumoniae could produces pigment 121.9 mg/l throughout 3 days. Furthermore, the result showed that 2g/l of L- tyrosine was the suitable conc. That led to increasing in the yield amount in addition the production occurred after 24hrs.The sixth pigment producing isolates showed, sensitivity to cephalothin and erythromycin. While about 16.6% from these isolate were resistant to tobramycin, gentamycin and ciprofloxacin, and 66.6% of isolates were resistant to cefotaxime and about 83.3% showed resistant to clarithromycin. The pigment that produced by Klebsiella pneumoniae HM was likely to that melanin pigment produced by other bacteria. The physical characteristics of produced pigment was a dark brown pigment in culture medium. The chemical analysis of suspected melanin pigment occurred by  solubility’s  method showed the pigment didn’t dissolve in D.W, HCl (1N), ethanol and chloroform but dissolve in NaOH (1N) only. FT-IR spectroscopy was chosen for further characterization of the suspected melanin pigment, melanin exhibited abroad absorption band at 3367.48 cm^-. The broadening of the band might be due to the hydrogen bonding of OH group with amine group. Another peak at 2929.67cm^-1 which appeared as a minute projection was assigned to N-H stretch.While absorption at 1080.06 cm^-1 may be attributed to aromatic ring CH stretching. Also the FTIR spectrum of extracted melanin result indicated there were amide linkages in the bacterial melanin, throughout a band at 1647.10 cm^-1 revealing the amide present in the molecule.

Download this article as