Repetitive sequence-based PCR (rep-PCR) is a distinctive typing approach that is used to
differentiate between bacterial strains. This method is also useful for studying bacterial diversity
from different sources. In this study, four rep-PCR which are enterobacterial repetitive intergenic
consensus PCR (ERIC-PCR), BOX-PCR, repetitive extragenic palindromic PCR (REP-PCR)
and polytrinucleotide (GTG)5-PCR were evaluated for differentiation of eighteen Escherichia
coli isolates to correct source based on part of intestine and age. These isolates were recovered
earlier from ileal and caecal mucosal contents of chickens at different age. The purpose of this
study was to investigate the efficacy of four rep-PCR methods and composite of rep-PCR
patterns to differentiate E. coli isolates to original sources of part of intestines and age based on
the D index (discriminatory power determined based on Simpson’s index of diversity calculated
at similarity coefficient of 90%). The (GTG)5-PCR had the highest D index (0.9804) for part of
intestine and age factors. The similar D index was observed in the composite of rep-PCR
patterns. The lowest D index was observed in ERIC- and BOX-PCR at 0.9020 and 0.8039 for
part of intestine and age factors, respectively. (GTG)5-PCR was also the most discriminative rep-
PCR observed due to its ability to cluster 14I 3E and 14I 2X isolates, and 14C 1E and 14C 3E
isolates correctly in part of intestine and age factors. It was concluded that (GTG)5-PCR is a
promising tool for discriminating E. coli isolates extracted from chicken intestines.
Melastoma malabathricum Linn. is a shrub that comes with beautiful pink or purple flowers and has berries-like fruits rich in anthocyanins. This study was carried out with the aim to evaluate the inhibitory activities of different concentrations of the M. malabathricum Linn. flower and fruit crude extracts against Listeria monocytogenes IMR L55, Staphylococcus aureus IMR S244, Escherichia coli IMR E30, and Salmonella typhimurium IMR S100 using the disc diffusion method. The lowest concentrations of the extracts producing inhibition zones against the test microorganisms were used to determine their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). In addition, the growth of Listeria monocytogenes IMR L55 and Staphylococcus aureus IMR S244 grown in medium supplemented with the respective extracts at different temperatures (4°C, 25°C, and 37°C) and pHs (4, 6, 7, and 8) was determined.