Department of Genetic Engineering and Biotechnologyhttp://dspace.ewubd.edu:8080/handle/123456789/142024-03-28T10:57:13Z2024-03-28T10:57:13ZDistinguishing the Disinfection Patterns of Listeria monocytogenes Contaminated Mozzarella Cheese by Using Gamma Irradiation TreatmentKundu, Shovanhttp://dspace.ewubd.edu:8080/handle/123456789/31282021-08-12T09:19:27Z2019-12-24T00:00:00ZDistinguishing the Disinfection Patterns of Listeria monocytogenes Contaminated Mozzarella Cheese by Using Gamma Irradiation Treatment
Kundu, Shovan
In today’s world, food safety is a major concern, as many people throughout the world are becoming infected with foodborne pathogens; such as Listeriosis caused by Listeria monocytogenes, which is responsible for death of many children, pregnant women and aged people every year. In this study, the disinfection pattern of L. monocytogenes was examined on mozzarella cheese by using gamma irradiation. After bacterial inoculation (108 cfu/gm) into sterile (25 kGy) cheese our individual tasted strains as 6, 8, 13, 14, 15 were treated with irradiation doses as 1 kGy, 3 kGy, 5 kGy, 7 kGy, 9 kGy and 10 kGy with a highly pathogenic reference strain L. monocytogenes ATCC 7466. The initial bacterial range was 9.5 log10 cfu/gm to 7.9 log10 cfu/gm. Results of irradiation treatments showed that, when the radiation doses were increased as 1 kGy to 10 kGy, the number of colonies were significantly decreased at 3 to 7 logs respectively. But in the middle level, radiation doses such as 5kGy and 7 kGy showed near about similar ranges of deductions for every strain, which were 3.3 log10 cfu/gm to 3.0 log10 cfu/gm. The most effective radiation dose was 10 kGy, where most of the bacteria were killed in all strains. The threshold level of this L. monocytogenes is 2 log10 cfu/gm which is much higher than our results. According to “The International Atomic Energy Agency (IAEA)”, 10 kGy radiation dose is standard to disinfect foods. This study indicates that, L. monocytogenes can grow in prepared dairy foods like cheese, yogurt etc. but this can be potentially disinfected by using gamma irradiation processes for improving food safety of ready-to-eat foods.
This thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Genetic Engineering and Biotechnology of East West University, Dhaka, Bangladesh.
2019-12-24T00:00:00ZIncidence of Norovirus Infection among Hospitalized Patients in Bangladesh: A Case-Control Study.Saha, Anikhttp://dspace.ewubd.edu:8080/handle/123456789/31272021-08-12T09:14:48Z2019-12-24T00:00:00ZIncidence of Norovirus Infection among Hospitalized Patients in Bangladesh: A Case-Control Study.
Saha, Anik
Norovirus is the most common cause of both outbreaks and sporadic non-bacterial gastroenteritis worldwide and one of the most common causes of acute gastroenteritis among children in developing countries. In this study, norovirus infections were investigated in diarrheal (Case) and non- diarrheal (Control) patients who have attended in nine hospitals during October, 2019 in Bangladesh. A total of 140 fecal specimens from both children and adults were tested for the presence of norovirus using real-time RT-PCR. Among them, ͠ 12% (n=16) of the specimens were found positive for norovirus RNA, among which only four were further genotyped by sequencing the partial capsid and polymerase gene. Norovirus GII was the most prevalent genogroup. Based on their clustering in the phylogenetic tree, two distinct genotypes were identified- GII.4 as the most prevalent genotype followed by one GII.3. A significant number of diarrhoeal patients hospitalized were found to be infected with norovirus; therefore, community surveillance is required to estimate the true burden of the virus in the country. Genomic analysis of the circulating norovirus strains would be very useful for understanding the pathogenesis and vaccine development. Moreover, the dynamic molecular epidemiology of norovirus requires routine strain surveillance to identify changes in prevailing strains.
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This thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Genetic Engineering and Biotechnology of East West University, Dhaka, Bangladesh.
2019-12-24T00:00:00ZIdentification and Differentiation of Acinetobacter calcoaceticus-Acinetobacter baumannii Complex by Multiplex PCR: Common Nosocomial Pathogens Among ChildrenIslam, Shubornohttp://dspace.ewubd.edu:8080/handle/123456789/31262021-08-12T09:15:39Z2019-08-25T00:00:00ZIdentification and Differentiation of Acinetobacter calcoaceticus-Acinetobacter baumannii Complex by Multiplex PCR: Common Nosocomial Pathogens Among Children
Islam, Shuborno
Acinetobacter baumannii is one of the most common pathogens causing nosocomial infections
worldwide involving a range of infections such as surgical site infections, pneumonia, urinary tract
infections and others. They are also an important pathogen to study due to multidrug resistant
worldwide, for which identification is very crucial for effective treatment. Acinetobacter is a
complex genus which contains multiple species, most of which have similar morphological
characteristics and biochemical properties leading to a complicated analysis process in a regular
routine care. This study was based on clinical isolates where Acinetobacter baumannii and other
closely related species of Acinetobacter, commonly called Acinetobacter calcoaceticus-
Acinetobacter baumannii (ACB) complex, were confirmed by conventional multiplex PCR using
primers targeting the ITS region followed by confirmation of Acinetobacter baumannii only by
RT-PCR using “blaOXA-51-LIKE” primers, which helped us to validate the different kinds of primers
as well as help us to compare the identification results between these multiple methods. At the
same time, the antibiotic susceptibility test (AST) results from the routine labs were analyzed using
these isolates to understand their resistance pattern. The results indicated that PCR methods were
able to confirm Acinetobacter baumannii more accurately compared to conventional biochemical
methods, and that both the primers can be used simultaneously without hesitation. We also found
the presence of other Acinetobacter species from the ACB complex which was not possible to
identify by conventional biochemical methods. On the other hand, Burkholderia cepacia was
found among these isolates indicating that, these isolates showed a conflicting biochemical results
with Acinetobacter species that might lead to misidentification. From the AST results, we found
out that Acinetobacter baumannii isolates showed high resistance pattern in almost all of the
available antibiotics. To conclude, conventional multiplex PCR method was a much better option
for identification due to low cost expenses which can be performed in a regular diagnostic routine
lab practices.
This thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Genetic Engineering and Biotechnology of East West University, Dhaka, Bangladesh.
2019-08-25T00:00:00ZDisinfection of Bacillus Cereus in Different Food Matrix using Gamma IrradiationRahman, Md. Shohanurhttp://dspace.ewubd.edu:8080/handle/123456789/31252021-08-12T09:16:02Z2019-08-25T00:00:00ZDisinfection of Bacillus Cereus in Different Food Matrix using Gamma Irradiation
Rahman, Md. Shohanur
Bacillus cereus is gram positive facultative anaerobic bacterium. It is a foodborne pathogen responsible for human food poisoning. In this study, growth and disinfection of B. cereus KTCC-11204 and B. cereus KTCC-400935 were examined in different food matrix using gamma radiation. Both of these strains were inoculated separately into fried rice and pasta samples which were collected from Dhaka. After appropriate incubation fried rice and pasta were irradiated using gamma radiation at 1 kGy, 3 kGy, 5 kGy, 7 kGy, 8 kGy and 9 kGy. Results showed that when the radiation doses were increased in fried rice, the number of colonies of B. cereus were significantly decreased. Both of the strains in fried rice were completely eliminated at 8 kGy of gamma radiation dose. Meanwhile, pasta samples showed similar results and complete elimination was obtained at 8 kGy gamma radiation dose. In both fried rice and pasta showed higher growth of KTCC-11204 than KTCC-400935. This study indicates that B. cereus can grow in prepared foods that can be potentially disinfected using gamma radiation which might be helpful in improving food safety of prepared foods.
This thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Genetic Engineering and Biotechnology of East West University, Dhaka, Bangladesh.
2019-08-25T00:00:00Z