Characterization and antibacterial activity of purified microcin produced by Klebsiella pneumoniae K15

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Research Paper 01/01/2019
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Characterization and antibacterial activity of purified microcin produced by Klebsiella pneumoniae K15

Aqeela Abdul-Zahraa, Ikbal Khudhur Al-joofy, Intesar Nadhum Khelkal
Int. J. Biosci.14( 1), 146-155, January 2019.
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This study has interested with the characterization and antibacterial activity of purified microcin of Klebsiella pneumoniae.  Isolates were collected and identified by morphological characteristics and biochemical tests of API 20E system. The diagnosis was confirmed by detection of 16S r RNA gene. Fifty-six (56%) of K. pneumoniae isolates were microcin producing, The majority of producer isolates are urine origin.  Optimum conditions for production were in brain heart infusion broth with 5% Glycerol, pH 7, 37 °C / 24 hrs. The efficient producer isolate of K. pneumoniae (K15) was chosen for microcin extraction and purification, inhibition zone ≥16mm. Antimicrobial susceptibility test was done for microcin producing isolates. No correlation was noticed between antibiotics resistance and microcin production. Extraction and Purification of microcin by method based on retention of the protein   lying on hydrophobic medium silica gel C60, eluted by methanol/water gradient from 20% – 80% concentration.  Protein concentration 80 µg/ml and specific activity 1U/µg. Final purification was done by HPLC. Molecular weight was determined by SDS-PAGE; 8-9 KDa.  Amino acid analysis by PITC, amino acids as following : (Asp), (Asn),  (Glu), (Gln), (Ser), (Gly), (His), (Arg), (Thr), (Ala), (Pro), (Tyr), (Val), (Met), (Cys), (Trp), (Ile), (Leu),  (Phe) at concentration of: 23.81, 53.44, 19.78, 17.39, 16.82, 17.73, 15.92, 15.16, 45.67, 31.17, 29.78, 28.90, 18.39, 28.29, 27.85, 22.31, 17.81, 30.47, 24.53 µg/ml respectively. Antibacterial activity of  microcin( 40 &80 µg/ml )  against 12  local  isolates were examined. In conclusion, local clinical K15 produce microcin exhibit inhibitory action on other pathogenic bacteria.


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