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| Articles
by
Nazneen Naher Islam |
Total Records (
2 ) for
Nazneen Naher Islam |
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Kamrun Nahar Islam
,
Touaha Akbar
,
Fahmida Akther
and
Nazneen Naher Islam
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A probiotic is a viable microbial dietary supplement that is beneficial for the host through its effects in the intestinal tract. Probiotics are widely used to prepare fermented dairy products such as yoghurt and it is an important source of probiotic Lactobacilli. In this study, the samples were collected from different superstores of Chittagong and Bogra city of Bangladesh. Pure culture of specific probiotic isolates from each sample was performed and identified on the basis of their colonies morphologies and some biochemical tests such as catalase, oxidase and IMViC (indole, methyl- red, voges proskavar, citrate utilization) test. Their identification as Lactobacillus spp., was confirmed through PCR reaction using genus specific primer. The isolated Lactobacillus spp., were resistant to inhibitory substances like NaCl (1-9%) and bile acid (0.05-0.3%). In addition, the satisfactory growth of isolated Lactobacillus spp., was observed in alkaline condition. The isolated Lactobacillus spp., showed positive result in different carbohydrate source such as glucose, xylose, galactose, etc and were able to produce organic acid in skim milk which was determined by titrimetic method. The Lactobacillus spp., was examined for their antimicrobial activities against some test pathogens by modified agar overlay method and the high inhibition zones showed their potential antibacterial effects. The yoghurt is suggested as a source of potential probiotic strains and there were variations in probiotic properties of the isolated Lactobacillus spp., obtained from selective regional yoghurt samples in this study. |
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Nazneen Naher Islam
,
Mahmuda Akter
,
Zinat Farzana
,
Abdul Jabber Bin Kader
,
Inkeyas Uddin
,
A.M.A.M. Zonaed Siddiki
and
K.M. Kamaruddin
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Staphylococcus aureus are gram positive cocci that can cause sporadic
cases and outbreaks of food borne illness. The aim of the present study was
to detect and identify this organism in samples of refrigerated chicken rinse
obtained from different super stores in Chittagong city. The prevalence of infection
and antimicrobial susceptibility of Staphylococcus aureus were also studied.
The PCR was performed to detect these microorganisms in a chicken rinse microbial
consortium and the traditional cultural techniques were performed based on bacteriological
analytical manual. To compare PCR and bacterial culture methods for detection
of S. aureus, 150 chicken rinse samples from different supermarkets in
the Chittagong city were collected and tested. Samples were cultured on selective
mannitol salt agar media and contamination by Staphylococcus was confirmed
by gram staining, catalase test and coagulase test. Overall 95.83% of the samples
were found to be infected with S. aureus. About 68.53% samples were coagulase
positive Staphylococcus and 31.46% were negative. Bacterial counts of
100000 or more CFU cm-2 were found on 16.67% of the frozen chicken
samples (p≤0.01). Simultaneously, total DNA obtained by thermal extraction
from samples was subjected to PCR using a set of primers designed for specific
regions of Staphylococcus nuc gene and PCR products were analyzed by
agarose gel electrophoresis. Culture sensitivity test and antibiogram study
was done to determine the antibiotic sensitivity pattern of Staphylococcus
isolates against eight commercially available antibiotic discs (Ampicillin,
Amoxycillin, Cephalexin, Ciprofloxacin, Erythromycin, Gentamycin, Doxycycline
hydrochloride and Oxytetracycline). All of the samples were resistant to two
or more than two antibiotics. The samples showed 100% resistant to Ampicillin,
more than 80% were resistant to Oxytetracyclin, Doxycycline hydrochloride and
Amoxicillin. Ciprofloxacin showed 77.5%, Cephalexin 38.33% and Gentamycin showed
the least resistance 13.33%. The results of this study indicate that the PCR
can permit a rapid and reliable means of assessing the bacteriological safety
of food and should provide an alternative methodology than conventional viable
culture method. The PCR may permit sufficient sensitivity and specificity for
the direct detection of Staphylococcus in food samples. |
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