AAU Institutional Repository (AAU-ETD)
Addis Ababa University Institutional repository is an open access repository that collects,preserves, and disseminates scholarly outputs of the university. AAU-ETD archives' collection of master's theses, doctoral dissertations and preprints showcase the wide range of academic research undertaken by AAU students over the course of the University's long history.
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Recent Submissions
―bovine mastitis in dair y farms in and around akaki kality sub city and sululta town: emphasis on isolation and identifica tion of pathogenic staphylococcus and antimicrobial susceptibility test of staphylococcus aureus
(Addis Abeba University, 2019) Getahun Tesfaye; HikaWaktole
A cross sectional study was conducted from November 2017 to May 2018 in and around Akaki Kality Sub-city of Addis Ababa and Sululta Town with major emphasis of isolation and identification of pathogenic Staphylococcus species and determination of antimicrobial susceptibility pattern of Staphylococcus aureus isolates. Besides the prevalence of clinical and sub-clinical mastitis and associated risk factors were investigated. A total of 768 lactating cows were examined by physical examinations of udder and by California mastitis test. Milk from clinical and sub clinical cases were cultured to isolate pathogenic Staphylococcus species. Antimicrobial susceptibility pattern of Staphylococcus aureus isolates was done by Kirby-Bauer disk diffusion method using eight antimicrobials.The overall prevalence of mastitis was 58.5%, out of which 10.8% was clinical and 47.7% subclinical mastitis.When the prevalence of study sites were considered separately it was 64.6% in Akaki Kality Sub-city, and 52.3% in Sululta Town of which clinical and sub-clinical mastitis were respectively 13.3% and 8.3% in Akaki Kality Sub-city and 51.3% and 44.0% in Sululta Town. In both study sites, univariable logistic regression analysis indicated bovine mastitis was more likely to occur with increasing age of cow, presence of teat lesion, poor housing hygiene and udder/teats hygiene. Based on primary and secondary biochemical characterizations and pathogenicity tests, pathogenic staphylococci were isolated in 25.4% at Akaki Kality Sub-city of which 18.5% was S. aureus, 4.03% S. intermidious and 2.8% S. hyicus. at Sululta, the proportions of pathogenic staphylococci were 20.9% of which S. aureus was 16.9%, S. intermedious was 2.5% and S. hyicus was 1.5%. A total of 68 Staphylococcus aureus isolates (34 of each study area) were assessed for antimicrobial susceptibility. Staphylococcus aureus from both study sites were resistant to ampicillin and penicillin. However, susceptibility to gentamicin was (91.2% and 85.3%), oxacillin (85.3 and
82.35%), cefoxitin (67.6% and 85.3%), erythromycin (70.6% and 94.11%), and vancomycin (82.35% and 91.2%) in Akaki Kality and Sululta Town, respectively. It could be concluded that prevalence of bovine mastitis in general, and isolation of pathogenic Staphylococcus species in particular was high in the study sites. The Staphylococcus aureus that were found to be totally resistant to ampicillin, and penicillin might be due to repeatedly use of these drugs.
Occurrence and Antimicrobial Susceptibility of Salmonella at Human Animal Environment Interface in Household Setting Bishoftu, Ethiopia
(Addis Abeba University, 2026) Fozia Hussien; Bekele Megersa; Fanta Desisa
Salmonella enterica is a leading cause of zoonotic illness, posing a significant public health concern in household settings, particularly where humans and animals share space and access to clean water, hygiene, and sanitation facilities is limited. The emergence of antimicrobial resistance complicates control efforts. From December 2025 to April 2026, a cross-sectional study was conducted to assess the occurrence and antimicrobial susceptibility of Salmonella at the human animal environment interface in household settings in Bishoftu, Ethiopia. A total of 266 households were included, and 1463 samples were collected from infant stool, soil, water, hand rinse, food, and animal feces. A household survey was conducted on hygiene, sanitation practices, and animal waste management, and antimicrobial use. Salmonella was confirmed using Matrix- Assisted Laser Desorption/Ionization time- of- flight (MALDI- TOF) mass spectrometry. Antimicrobial susceptibility testing was performed using the Kirby- Bauer disk diffusion method for nine antibiotics. Critical sanitation gaps included infrequent water treatment (93.98%) and (73.68%) shared latrines, most without handwashing facility (78.5%). The animal waste management system was poor; 73.7% of households either disposed of waste in a waste bin or rubbish pile or did nothing at all, indicating that nearly three-quarters of households lacked proper waste management practices. 80.1% caregivers were unaware of AMR transmission between animals and humans. Over all Salmonella prevalence was 2.12% and the highest prevalence was recorded in animal feces (6.8%). Of 31 82.8% were susceptible, 5.4% showed intermediate resistance, and 11.8% of them exhibit resistance and the highest resistance was tetracycline (32.26%). MDR occurred in 6.5% isolates and all recorded from
soil. In conclusion, the study demonstrates critical gaps in sanitation and animal waste management. These finding confirms that poor household practice and animal waste contribute to Salmonella transmission and antimicrobial resistance, underscoring the urgent need for integrated one health interventions.
Abattoir Based Study of Epidemiology of Caprice Tuberculosis Using Conventional and Molecular Tools
(Addis Ababa University, 2012-12) Benti Deressa; Gobena Ameni; Franz J Conraths
Tuberculosis is an infectious disease occurring in several animal species including domestic
and wild animals, as well as hennas. A cross-sectional study was conducted from March to
September 2011 on 1990 randomly selected male goats slaughtered at Luna Export Abattoir
to estimate the prevalence of tuberculosis (TB), evaluate associated risk factors, and
molecularly characterize the causative agents. Postmortem examination, mycobacterial
culturing, Genus typing, region of difference (RD) based polymerase chain reaction (PCR)
and spoilage typing were the techniques used in the study. The overall prevalence of caprice
tuberculosis was 3.5 % (6911990).There was marked variation in TB prevalence between the
age categories and it was significantly higher in older goats (> 1.5 year) (X2 =6.436;
P=O.O II ).Variation of the disease between the different goat types and origins were not
statistically significant (P>0.05). Mediastina lymph node was the most severely (0.52±0.084)
and frequently (42%) affected tissue of goats. Culture and acid fast bacillus positivity was
confirmed in 12 % (8/69) of the goats with grossly visible tuberculosis lesion. Up on further
molecular characterization using multiplex PCR, five of the culture positive isolates showed
signal for the Genus Mycobacterium, of which four were identified to be members of the
Mycobacterium tuberculosis complex. Deletion typing targeting RD4 performed on the four
isolates showed the evidence of the presence of RD4 in three isolates which appeared on the
gel. Further characterization of the three isolates using RD9 deletion typing has showed that
all of them were M tuberculosis. Spoleto typing of the isolates confirmed that one of the
isolate is SIT53where as the other two were new strains. The isolation of M tuberculosis
from goats in this study suggests evidence of transmission from humans. This also raises the
concern of the risk of transmission from goat-to-human and the need to raise awareness
among pastoralists consuming raw milk and meat derived from goats.
Keywords: Caprice tuberculosis, Epidemiology, Molecular typing, Abattoir, Ethiopia
Handling, processing and utilization practices of Milk products in the highlands of Southern Tigray, Ethiopia
(Addis Ababa University, 2012-04-20) Abraha Negash; Ashenafi Mengistu
Cross-sectional study was carried out with the aim of assessing milk products handling,
processing and characterize the utilization practices in dairy farmers of Ofla, Enda-Mekoni
and Emba-Alaje Weredas in highlands of Southern Tigray, Ethiopia. A total of 156
households possessing a dairy farm, of which 47 urban, 20 periurban and 89 rural were
studied using Probability prop0l1ionai to size approach sample determination. Peculiarity of
the area was that butter hair ointment and custom of dying white close in to greyish was
different to the utilization of milk products in Ethiopia. Out of the total respondents,
42.31 %of them sell fresh milk, 1.92% buttermilk and yoghurt, 98.08% butter to consumers of
which 93.26% of them were rural respondents. Milk products handling and processing were
using local vessels treated with different plant materials by cleaning and smoking. Milking
vessels that are in use for the purposes include 'gibar' (9.62%), plastic materials (55.13%)
and 'karfo' (35.26%). Farn1ers use different utensils for souring milk which included 'qurae'
made of clay pot (16%), plastic vessels (54.5%) or gourd (29.5%) whereas for storing ghee
66.03% of the respondents use in plastic, followed by 30.13% who used 'qurae' and 3.21 % of
them use stainless steel vessels. There was significant (p<0.05) difference in the use of
churning vessels in the study area where 93.6% of respondents use' laga ' while the others use
water tight plastic vessel. Butter handling practice is generally using 'qorie' that could vary in
size and type made from glass (2.6%), stainless steel (6.5%), log (7.1%), 14.2% 'gibar',
plastic (17.4%) and gourd (52.3%). The log 'qorie' was best butter handling material, but not
easily accessible. Butter milk termed as 'awuso' and spiced butter milk 'hazo' are stored in
clay pot, plastic and stainless steel. For improving the shelf life of the different milk products,
fanners use various species of plants which are used for cleaning and smoking of utensils
used for storing the products. These included: Olea europaea, Dodoneae angustifohia and
Anethum graveolens were dominant plants exploited for smoking milk vessels while Cliclimis
prophertarum, Zehneria scabra (L. fil) sonder and Achyranthes aspera were all rough in
nature to clean the grooves of the clay pot and churner. Identification of the active ingredients
contained in these plants would help their commercial use for improving the shelf life of milk
and milk products at a smallholder level as well as at a larger scale with the aim of increasing
the income generation capacity of dairy enterprises.
Studies on the Prevalence, Ecology and Antibiogram of Staphylococcus Species Isolated from Chickens Slaughtered at Small and Large Scale Poultry Farms in Debre Zeit, Ethiopia
(Addis Ababa University, 2012-06-01) Sihin Tesfaye; Mahendra Pal
A cross-sectional study to determine the prevalence, species involved and antimicrobial profile of
Staphylococcus species isolated from chicken carcass, equipment and hands of apparently healthy
the abattoirs workers was undertaken from November 2011 to April 2012. A total of 384 samples
consisting of chicken carcass (n=340), abattoir equipment (n=24) and workers' hands (n=20)
were taken from large and small scale poultry farms in Debre Zeit. A total of 187 (47.7%)
Staphylococcus species were isolated from chicken carcass and immediate slaughter environment
and were further identified to species level by important conventional biochemical tests.
Furthermore, species identification was made by OmniLog reading. From the total of 187
staphylococci isolated, Staphylococcus aureus, S. intermedius, S. hyicus and coagulase negative
staphylococci species contributed 13.8%, 9.6%, 6.8% and 17.4%, respectively. Regarding the
origin of the samples, among isolates of the carcass swabs 12.4%, 9.1 %, 6.5% and 17.7% were
identified as S. aureus, S. intermedius, S. hyicus and coagulase negative staphylococci,
correspondingly. While in the immediate slaughter environment the rates of isolation were
25.0%, 13.6%, 9.1% and 15.9%, respectively for the aforementioned species. Consequently,
statistically significant association (p= 0.022) was observed in the prevalence of S. aureus
between the two types of sample origin. No statistically significant associations of the prevalence
of the rest species were detected amongst the carcass and environmental samples. In the large
scale farms, the prevalence of Staphylococcus species were, S. aureus 11.5%, S. intermedius
8.3%, S. hyicus 6.3% and CNS 16.7%. In the small scale farms the isolation rates of the isolates
were S. aureus 16.1 %, S. intermedius 10.9%, S. hyicus 7.3% and CNS 18.2%. A higher isolation
frequency of all species was noted in the small scale farms; however, these differences were not
statistically significant. In this study, varying level of resistance of S. aureus (100%) to
bacitracin, methicillin, neomycin and polymixin was noticed. The susceptibility pattern indicated
S. aureus isolates exhibited varying level of resistance to two or more antimicrobial agents.
66.6% of the isolates showed susceptibility to the tested drugs