College of Natural and Computational Sciences

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The College of Natural and Computational Sciences advances education, research, and innovation in natural sciences, mathematics, statistics, and computational disciplines.

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    ISOLATION, MOLECULAR DETECTION AND ANTIMICROBIAL SUSCEPTIBILITY OF SALMONELLA FROM COW MILK AND BEEF IN SELECTED DISTRICTS OF SIDAMA REGIONAL STATE, ETHIOPIA
    (HAWASSA UNIVERSTY, 2023-10) TARIKU GEINORO ALLEYO
    Salmonella is one of the most common causes of foodborne diseases and frequently reported for exacerbating increase of multi-drug resistance worldwide. Unhygienic practices throughout food chain and cultural habits of raw animal products contributed for the expansion of the infection and increment in antimicrobial resistance especially in developing world like Ethiopia. A cross- sectional type of study was conducted from December, 2022 to June, 2023. The study was aimed with isolation, molecular detection and determination of antimicrobial susceptibility of Salmonella from cow milk and beef in Hawassa, Yirgalem and Wondo Genet districts of Sidama Regional State. A total of 216 samples of which 152 milk and 64 beef samples were collected with purposive and simple random sampling methods for isolation and biochemical identification of Salmonella. Positive isolates obtained from bacteriological and biochemical tests were further confirmed by polymerase chain reaction (PCR). Then, the isolate’s antimicrobial susceptibility profile was tested by using disk diffusion method for twelve selected antimicrobials. SPSS windows version 25.0 was used for statistical analysis. Fisher’s exact test was the measure of association of isolates with different attributes. Bacteriological and biochemical detection tests revealed that 6.5% (N=14/216) Salmonella was isolated from the total sample. However, in molecular detection, only 9 of the 14 isolates were confirmed to be Salmonella using PCR test, which was 4.17% of the total. The proportion was 5.38%, 3.23%, and 2.38% in Hawassa, Yirgalem and Wondo Genet districts, respectively. There was no significant variation in prevalence among the districts and between sample types milk (3.9%) and beef (4.7%) (p > 0.05). Similarly, no significant (p > 0.05) variation was observed in the Salmonella isolation rate among retailers (4.84%), households (5.56%) and farms (1.85%) as well as between yoghurt (6.45%) and raw (3.31%) milk. The result of the antimicrobial susceptibility test showed that Salmonella isolates were 100% resistant to ampicillin, nalidixic acid, clindamycin and cephalothin while they were above 50% sensitive to ceftriaxone, chloramphenicol and gentamycin. Multi-drug resistance (MDR) was demonstrated in all isolates. Overall, this study showed that Salmonella was prevalent in cow milk and beef produced and consumed; and developed MDR which may pose public health concern in the study area. Thus, subsequent regular investigations on serotypes, AMR genes and risk factors as well as rational use of antimicrobials is necessary.
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    ISOLATION, MOLECULAR IDENTIFICATION AND ANTIMICROBIAL SUSCEPTIBILITY PROFILING OF ESCHERICHIA COLI O157:H7 STRAIN ISOLATED FROM ANIMAL-ORIGIN FOODS IN HAWASSA AND YIRGALEM, SIDAMA, ETHIOPIA.
    (HAWASSA UNIVERSITY, 2024-11) WORKAGEGN ISRAEL ASALE
    Escherichia coli O157:H7, an important foodborne pathogen, posing serious public health concern globally. This study conducted from December 2022 to July 2023 with the aim to isolate, molecularly identify and evaluate the antimicrobial susceptibility profiles of Escherichia coli O157:H7 isolated from animal-origin foods including beef, raw milk and fish in Hawassa and Yirgalem towns of Sidama region, Ethiopia. In this study, a total of 298 different samples were collected and analyzed for isolation and identification of Escherichia coli O157:H7 using culture, biochemical tests and PCR analysis. PCR analysis showed that Escherichia coli O157:H7 was isolated from 3.7% of the total samples of which 5.6% and 6.25% were isolated from beef and fish samples, respectively, and no Escherichia coli O157:H7 isolate was observed from milk samples. The observed isolation rate among the different food type samples was statistically significant (p = 0.036). It was revealed that meat samples collected from butcher shops were found to be more (7.6%) contaminated by Escherichia coli O157:H7 than samples from abattoirs (3.4%) (p = 0.445). Regarding fish samples, contamination level was greater in Nile tilapia (8.1%) than Catfish. Similarly, higher (7.3%) contamination was observed from samples collected from Gudumalle fish landing site than other sites. Moreover, fish skin was the more (8.6%) contaminated organ than fish muscle (3.4%). Antibiotic susceptibility test demonstrated that all Escherichia coli O157:H7 isolates exhibited 100% susceptibility to ciprofloxacin, nalidixic acid, chloramphenicol, cephalothin, ceftazidime, ceftriaxone, tetracycline, and gentamicin whereas a 81.8%, 45.5% and 100%resistance was observed in amoxacillin, streptomycin and clindamycin, respectively. The multidrug resistance observed in 45.45% of isolates with the calculated MDR index of 0.27, and no extended-spectrum beta-lactamase (ESBL) producing isolates were detected. The findings highlight the need for stringent hygiene practices and effective monitoring of animal origin foods to minimize the risk of public health threats.
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    PHYSICOCHEMICAL CHARACTERIZATION, PROXIMATE ANALYSIS AND DETERMINATION OF SELECTED HEAVY METALS IN COW’S MILK AND COW’S FEED “ATELLA” SAMPLES COLLECTED FROM ARSI NEGELLE TOWN, OROMIA REGION; ETHIOPIA.
    (Hawassa University, 2024-11) TAJURA USMAN
    Arsi Negele, also known as NegeleArsi, is primarily known for its production of Areki,a traditional alcoholic beverage, and its byproduct atella, which is widely used to feed cows to enhance milk production. However, concerns about heavy metal contamination from agricultural practices associated with Areki's raw materials have emerged, highlighting potential health risks linked to cow's milk and feed in the area. This study focuses on physicochemical characterization, proximate analysis and determination of selected heavy metals (Cr, Zn, Cu, Ni, Fe, and Pb) in milk and atella samples. Samples of milk and atella were collected purposively from five sites: meja kiltotasefar, kiltu demasefar, melka shayitsefar, Agip sefar, and mobile sefar. In ArsiNegelle town, and homogenized. The physicochemical properties and proximate analyses were performed by following the AOAC method. The concentrations of the heavy metals were analyzed using Flame Atomic Absorption Spectrometry (FAAS). All the samples were analyzed in replicates, and the mean values are presented. The obtained results showed that the (temperature, pH) were (20.3 ± 0.26, 6.74 ± 0.01) for the composite milk sample and (20.7 ± 0.01, 4.07 ± 0.02) for atella sample. The results of proximate analysis such as moisture, dry matter, crude protein ,crude fat, crude fiber, total ash, carbohydrate and gross energy contents of milk samples were 78.5 ± 0.486 % , 3.84 ± 0.03 %, 4.53 ± 0.251 %,3.35 ± 0.02 %,1.7 ± 0.1 %,0.436 ± 0.015 %, 7.23 ± 0.02 % and 64.34 ± 0.023 kcal/g, respectively. On the other hand, the respective mean values of proximate analysis of atella sample were 11.36 ± 0.20 %, 17.56 ± 0.01 %, 14.7 ± 0.2 %, 11.36 ± 0.20 %,, 17.56 ± 0.01, 14.7 ± 0.2 %, 42.36 ± 0.23 % and 276.71 ± 0.23 kcal/g respectively. From the analyzed metals Pb, Cr and Ni were not detected whereas the mean concentrations of Fe, Cu, and Zn were in the range of (0.037 – 1.363), (0.0983 – 0.853), and (0.926 – 0.971) mg/L respectively for the (milk, atella) samples. While the physicochemical and proximate analysis reinforced the claims of the traditional community that atella is nutritious feed for cows as evidenced by the proximate composition of milk. Although the levels of the heavy metals in both atella and milk samples were in the permissible range as stipulated by WHO, the study further revealed implications of carryover of the heavy metals from the cow’s feed atella to the milk.