Browsing by Author "Tesfaye Sisay"

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    A Comparative Study on Bacterial Distribution in the Respiratory Tracts of Ruminants
    (Addis Ababa University, 2011-06-01) Biruk Tesfaye; Tesfaye Sisay
    For this study pneumonic lung tissue and tracheal swabs were collected from sheep, goat and cattle slaughtered at Addis Ababa abattoir. From the total of 170 bacterial isolates from sheep lung tissue 42.4% Staphylococcus species, 14.7% Mannheimia haemolytica and 10.6% Bacillus species were isolated aerobically. The tracheal cultures also indicate that 66.7% were M. haemolytica, 13% were Bibersteinia trehalosi and 5.8% were identified as Enterobcter species from the total of 69 cultures that cultured aerobically. Out of 192 bacteria isolated from aerobic inoculation of goat lung 45.3% were Staphylococcus species followed by Bacillus species 19.8%, Micrococcus species, 12.5% and M. haemolytica 6.3% of the total isolates. The tracheal culture showed Enterobacter species 30.1 %, M. haemolytica 27.7% and Bacillus species 26.5%. Twenty-nine Staphylococcus species were among 93 bacterial isolates of aerobic cultures of cattle lung followed by Bacillus species, 17 and M. haemolytica, 8. While Staphylococcus, B. trehalosi, and M. haemolytica were account for 18, 14, and 8 out of the total 57 tracheal cultures respectively. A total of 522 bacterial isolates were detected via anaerobic culture, in which 40% of the 131 isolates from sheep lung were Staphylococcus species, 25.4% were M. haemolytica, and 6.2% were Bacillus species while B. trehalosi and Micrococcus species took 5.4% each from the total isolates. Whereas, 60.6% M. haemolytica , 19.7% B. trehalosi and 12.7% Enterobacter species were isolated from a total of 71 sheep trachea culture isolates. Among anaerobic cultures of goat lung tissue Staphylococcus species accounts for 36% followed by Bacillus species, 25.6% and M. haemolytica 11.2% out of the total 125 bacterial species. In the tracheal culture M. haemolytica counts for 33 followed by Bacillus species, 14 and Enterobacter species, 7 from 61 isolates. 42.9% Staphylococcus, 23.4% Bacillus species and 7.8% B. trehalosi were isolated species from the lung of the cattle, while from the trachea 25.0% M. haemloiytica and Staphylococcus each were isolated anaerobically. A total of 1556 bacteria were isolated from 960 nasal swabs from three different areas. In Debre Berhan 140 M. haemolytica, 81 Histophilus somni, 57 Staphylococcus species and 52 B. trehalosi were isolated. While from Gimba M. haemolytica, Staphylococcus, Streptococcus and H. Somni of which contribute for 25.2%, 15.9%, 11.4 % and 5.9% of the total 647 bacterial species were observed respectively. In Asella from 352 bacterial species isolated 93 were M. haemolytica, 48 were Staphylococcus species, 26 were B. trehalosi and 17 H. somni were recognized. Further identification and characterization was made using BIOLOG identification system at the Institute of Biodiversity Conservation, Addis Ababa, and the result indicate that Enterococcus avium and Sphingomona Sanguinis were identified at 100% probability, while. H.somni and Actinobacillus lignerisii were suggested by the system
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    Alongitudinal Study on Occurrence of Staphylococcus aureus and its Drug Resistance Pattern in Raw Bovine Milk Originated From Alage TVET College Dairy Farm, Ethiopia
    (Addis Ababa University, 2012-06) Elias Gezahegn; Tesfaye Sisay
    A longitudinal study was conducted from November 2011 to April 2012 to investigate the contamination rate of Staphylococcus aureus in raw and processed bovine milk in Algae ATVET College. The rate of raw milk contamination along lactation length, the role of some potential risk factors, and degree of antibiotic resistance to the study organism was also addressed. A total of 316 (265 udder and 51 raw processed) milk samples were analyzed and 20.3% (64/316) were found contaminated with S. aureus. The rate of contamination in udder milk and raw processed milk was 20.8% (55/265) and 17.6% (9/51), respectively. The longitudinal study done indicated that the rate of contamination at early, mid and late stage of lactation was, 40.5% (30174), 11.2% (10/89) and 14.7% (15/ 102) respectively. There was statistically significant difference (P<0.05) in rate of contamination between early and late lactation stages. The calculated odd ratio for early and late lactation stage was 3.955 (CI= 1.929, 8.101 ). Udder milk from cows with two or more parity number and high milk yielders also revealed significant (P<0.05) contamination rate with S. aureus when compared with cows having less than two parity number (OR= 5.81, CI= 2.898, 11.765) and low milk yielders (OR= 4.83 , CI= 1.88, 12.35), respectively. From the raw processed milk samples, the higher percentage of occurrence was at milk destination sites 'B' and 'C', 33.3% each. The antibiotic susceptibility test indicated the study microorganism was highly susceptible to chloramphenicol (76.9%) followed by erythromycin (71.8%) and trimethoprim sulfamethoxazole (64. 1%). However, these isolates were equally resistant to doxycycline and nalidixic acid (36.1 %) following ampicillin for which they were highly resistant (94.9%). From the 39 pure isolates, 82.1 % were resistant for two or more drugs. The multidrug resistance pattern done for isolates from different parity group was statistically insignificant (P>0.05) In conclusion, this study indicated the importance of S. aureus in milk contamination in the study area. It also indicated lactation stage, milk yield and parity number of lactating cows were the potential risk factors for the contamination of udder milk. Measure should be taken to address the antibiotic resistance in the study farm . Keywords: Occurrence, Raw processed milk, Staphylococcus aureus, Udder milk.
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    Assessment of Bacteriological Quality of Camel Raw Milk in Selected Pastorial Kebeles, Fentale District, Oromfya Region, Ethiopia
    (Addis Ababa University, 2012-06-01) Aklilu Feleke; Tesfaye Sisay
    The current study was undertaken to assess the bacteriological quality of raw camel milk and to isolate and identify prevalent bacterial species from raw camel milk from study areas. A total of 420 milk samples (384 from lactating camels and 36 from milking utensils) were collected from August 2011 to April 2012. An observational study was conducted to gain an insight on pre-harvest. harvest and post-harvest milk hygiene practices. The standard plate count and coliform count as well as isolation and identification of bacteria from camel milk were carried out by employing standard microbiological techniques. The mean standard plate count for milk sample taken from the udder of' lactating camels and milking utensils were 4.30 log10 CFU/ml and 5.34 log10 CFU/ml, respectively. A statistically significance difference was observed between the two means (P= 0.000). The mean coliform count of milk samples collected from the udder of lactating camels and milking utensils were 0.98 log10 CFU/ml and 3.57 log10 CFU/mI. respectively. There was also a statistically significant difference between the two mean (P=0.000). Clinically mastitic udder have role as a source of' Staphylococus aureus,S.hicu,.Streptococcus galactic. S. dysgalactia. Enlerococcus faecalis. Bacillus spp Eschericia coli and Mannheimia hemolytica in camel milk. Subclinical mastitis acts as a source of contamination for microbes such as Staphylococcus. aureus, S. hyicus, S. intermedius. Enterobacter aerogenes,Escherichia coli and Cyanobacteria spp .. Likewise, milk form the also yielded several bacteria which included S. aureus, S. epidermidis, Streptococcus agalactiae, S. uberis, Enterococcus faecalis, Klebsiella pneumonia and Pseudomonas spp .. On the other hand, milking utensils served as an important source of' Escherichia coli and Staphylococcus epidermidis. A higher bacterial counts was observed in milk samples taken from milking utensils as compared to the milk samples collected directly from the udder indicating poor milk hygiene/ manufacturing practices. The prevalence of infectious mastitis can result in reduced milk yield and poor quality of milk. In addition, consumption of' raw camel milk by herdsmen may pose considerable health hazards
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    Bacteriological Studies on the Respiratory Tracts of Apparently Healthy and Pneumonic Camels (Camel Us Dromedaries) in Selected Districts of Afar Region, Ethiopia
    (Addis Ababa University, 2012-06-01) Mu'uz Gebru; Tesfaye Sisay
    A cross-sectional study was conducted to isolate and characterize the normal bacterial flora and bacterial agents implicated in pneumonia from the respiratory tract of the apparently healthy and pneumonic camels in the selected districts of Asayita and Dubti woredas of Afar Region. A total of 532 samples including 384 nasal swabs, 74 lung tissues and the same number of corresponding tracheal swabs were collected for bacteriological examination from September 2011 to May 2012. Generally, 903 bacterial isolates that constituted 14 different genera were identified from both the field and abattoir based study. The 384 nasal specimens collected yielded a total of 641 bacterial isolates. CNS, 28.6%, Bacillus, 13.5%, S. aureus, 13.3% and E. coli, 7.8% were the leading bacterial species isolated from the nasal tracts of apparently healthy camels. Nasal swabs collected from the pneumonic camels revealed S. aureus, CNS, Bacillus species and K. pneumoniae at a rate of 28.0%, 11.7%, 11.3% and 7.0%, respectively. E. coli, 12.7%, Proteus species, 10.9%, and K. pneumoniae, 9.1 % were recognized at higher proportions among the 55 bacteria identified from the normal lungs. On the other side, S. aureus, S. equi subsp. eqlli and P. multocida were the frequently encountered species in the pneumonic lungs with the incidence of 16.3%, 13.0% and 10.9%, respectively. The majority of the isolates colonized all the anatomical sites investigated. However, a general decrease in the isolation rate was observed as one goes down the respiratory passageways. There was a statistically significant difference between the health status of the camels as well as along the anatomical sites studied with the isolation rates of the major camel respiratory pathogens (p<0.05). Streptococcus eqlli subsp. equi, S. equi subsp. zooepidemicus and S. pneumoniae were identified using the Omnilog®-Biolog identification system at the Institute of Biodiversity Conservation, Addis Ababa. The majority of the strains of the camel respiratory pathogens were found susceptible to norfloxacin, streptomycin and gentamicin but resistant to the action of ampicillin and tetracycline on the invitro test. Further studies on the demonstration of the role of other microorganisms, the pathogenicity of S. equi subsp. equi, identification of the serotypes involved and development of polyvalent vaccine are recommended to allow the progress of preventive methods
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    Bacteriological Studies on The Respiratory Tracts of Apparently Healthy and Pneumonic Camels (Camelus Dromedaries) In Selected Districts of Afar Region, Ethiopia
    (2012-06) Mu’uz Gebru; Tesfaye Sisay
    A cross-sectional study was conducted to isolate and characterize the normal bacterial flora and bacterial agents implicated in pneumonia from the respiratory tract of the apparently healthy and pneumonic camels in the selected districts of Asayita and Dubti woredas of Afar Region. A total of 532 samples including 384 nasal swabs, 74 lung tissues and the same number of corresponding tracheal swabs were collected for bacteriological examination from September 2011 to May 2012. Generally, 903 bacterial isolates that constituted 14 different genera were identified from both the field and abattoir based study. The 384 nasal specimens collected yielded a total of 641 bacterial isolates. CNS, 28.6%, Bacillus, 13.5%, S. aureus, 13.3% and E. coli, 7.8% were the leading bacterial species isolated from the nasal tracts of apparently healthy camels. Nasal swabs collected from the pneumonic camels revealed S. aureus, CNS, Bacillus species and K. pneumoniae at a rate of 28.0%, 11.7%, 11.3% and 7.0%, respectively. E. coli, 12.7%, Proteus species, 10.9%, and K. pneumoniae, 9.1% were recognized at higher proportions among the 55 bacteria identified from the normal lungs. On the other side, S. aureus, S. equi subsp. equi and P. multocida were the frequently encountered species in the pneumonic lungs with the incidence of 16.3%, 13.0% and 10.9%, respectively. The majority of the isolates colonized all the anatomical sites investigated. However, a general decrease in the isolation rate was observed as one goes down the respiratory passageways. There was a statistically significant difference between the health status of the camels as well as along the anatomical sites studied with the isolation rates of the major camel respiratory pathogens (p<0.05). Streptococcus equi subsp. equi, S. equi subsp. zooepidemicus and S. pneumoniae were identified using the Omnilog®-Biolog identification system at the Institute of Biodiversity Conservation, Addis Ababa. The majority of the strains of the camel respiratory pathogens were found susceptible to norfloxacin, streptomycin and gentamicin but resistant to the action of ampicillin and tetracycline on the invitro test. Further studies on the demonstration of the role of other microorganisms, the pathogenicity of S. equi subsp. equi, identification of the serotypes involved and development of polyvalent vaccine are recommended to allow the progress of preventive methods.
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    Breast Cancer Subtypes, Associated Biomarkers, and the Involvement of Human Papilloma Virus in Ethiopian Population
    (Addis Ababa University, 2023-12-22) Esmael Besufikad; Adey Feleke; Tesfaye Sisay; Rawleigh Howe
    Breast cancer is the most common type of cancer in the world as well as in Ethiopia. Although research on breast cancer in Ethiopia has been conducted, none of them have evaluated breast cancer in multiple regions of the country, which is important considering Ethiopia’s enormous ethnic and genetic diversity. Hence, this study was carried out to evaluate the distribution of breast cancer subtypes and associated immune cell biomarkers, hormone receptors, matrix metalloproteinases (MMPs), and HPV genotypes in selected Ethiopian regions. A total of 227, 81, 58, and 120 formalin-fixed paraffin-embedded (FFPE) tissue blocks were collected for breast cancer subtyping, immune cell biomarkers analysis, MMP expression, and HPV genotyping, respectively. Immunohistochemistry (IHC) staining was performed for breast cancer subtyping based on estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 proliferation markers, and for additional immune cell biomarker expression. RNA was extracted and quantitative reverse-transcription PCR was performed for MMP expression analysis. DNA was extracted from archived FFPE breast tissue specimens and target genes were amplified using PCR for HPV genotyping. SPSS Version 25 was used to enter and analyze data. For immune cell biomarkers and MMP results, GraphPad Prism version 8.0.0 was used for statistical analysis. A large percentage of breast cancers were found to have advanced clinical and pathologic features, such as substantial lymph node involvement, large tumor size, and high histological grade. The percentage of ER and PR-negative tumors were 48.3% and 53.2%, respectively. The IHC subtype distribution was 33.1% triple-negative (ER-, PR-, HER-2-) breast cancer, 27.6% luminal B ((ER+, PR+, HER-2- and Ki-67 ≥ 20%) or (ER+, PR+, and HER-2+)), 25.2% luminal A (ER+, PR+, HER-2- and Ki-67< 20%), and 14.1% HER-2- enriched (ER-, PR-, HER-2+). In multiple logistic regression analysis, grade III and HER- 2 positivity were associated with larger tumor size, and tumor size was also higher in samples from Southwestern Ethiopia (Jimma) as compared to Northern Ethiopia (Mekele). The MMP-11 expression levels were significantly higher in breast cancer cases than in benign breast tumors (P=0.012). The non-luminal (triple-negative and HER-2-enriched) breast cancer subtype had a higher percentage of stromal CD20+, intratumoral CD3+ tumor-infiltrating lymphocytes, and CD68+ tumor-associated macrophages than the luminal (Luminal A and Luminal B) subtype. The stromal programmed cell death ligand 1 (PD-L1) +, intratumoral CD3+ tumor-infiltrating lymphocytes, CD163+ tumor-associated macrophages, and PD-L1+ were also more commonly found in grade III breast cancer than in grade I and II breast cancer, respectively. Human papillomavirus was found in 20.6% of breast cancer patients and 29.6% of non-malignant breast tumors. Human papillomavirus infection was nearly 10-fold more common in ER-positive than ER-negative breast cancer. A considerably high prevalence of triple-negative breast cancer was reported in our study, demanding additional research that includes identifying genetic predisposition factors. A significant association was found between the breast cancer subtype and stromal CD20+, intratumoral CD3+ tumor-infiltrating lymphocytes, and CD68+ tumor-associated macrophages. The stromal PD-L1+, intratumoral CD3+ tumor-infiltrating lymphocytes, CD163+ tumor-associated macrophages, and PD-L1+ were also associated with tumor grade. Our findings suggest an important impact of MMPs in breast cancer pathophysiology, particularly MMP-11. This study also showed no proof of a link between HPV infection and breast cancer; however, the finding that HPV was more prevalent in breast tumors that were ER-positive than ER-negative warrants further attention.
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    Breast Cancer Subtypes, Associated Biomarkers, and the Involvement of Human Papilloma Virus in Ethiopian Population
    (Addis Ababa University, 2023-12-22) Esmael Besufikad; Adey Feleke; Tesfaye Sisay; Rawleigh Howe; Dinkisira Bekele
    Breast cancer is the most common type of cancer in the world as well as in Ethiopia. Although research on breast cancer in Ethiopia has been conducted, none of them have evaluated breast cancer in multiple regions of the country, which is important considering Ethiopia’s enormous ethnic and genetic diversity. Hence, this study was carried out to evaluate the distribution of breast cancer subtypes and associated immune cell biomarkers, hormone receptors, matrix metalloproteinases (MMPs), and HPV genotypes in selected Ethiopian regions. A total of 227, 81, 58, and 120 formalin-fixed paraffin-embedded (FFPE) tissue blocks were collected for breast cancer subtyping, immune cell biomarkers analysis, MMP expression, and HPV genotyping, respectively. Immunohistochemistry (IHC) staining was performed for breast cancer subtyping based on estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 proliferation markers, and for additional immune cell biomarker expression. RNA was extracted and quantitative reverse-transcription PCR was performed for MMP expression analysis. DNA was extracted from archived FFPE breast tissue specimens and target genes were amplified using PCR for HPV genotyping. SPSS Version 25 was used to enter and analyze data. For immune cell biomarkers and MMP results, GraphPad Prism version 8.0.0 was used for statistical analysis. A large percentage of breast cancers were found to have advanced clinical and pathologic features, such as substantial lymph node involvement, large tumor size, and high histological grade. The percentage of ER and PR-negative tumors were 48.3% and 53.2%, respectively. The IHC subtype distribution was 33.1% triple-negative (ER-, PR-, HER-2-) breast cancer, 27.6% luminal B ((ER+, PR+, HER-2- and Ki-67 ≥ 20%) or (ER+, PR+, and HER-2+)), 25.2% luminal A (ER+, PR+, HER-2- and Ki-67< 20%), and 14.1% HER-2-enriched (ER-, PR-, HER-2+). In multiple logistic regression analysis, grade III and HER-2 positivity were associated with larger tumor size, and tumor size was also higher in samples from Southwestern Ethiopia (Jimma) as compared to Northern Ethiopia (Mekele). The MMP-11 expression levels were significantly higher in breast cancer cases than in benign breast tumors (P=0.012). The non-luminal (triple-negative and HER-2-enriched) breast cancer subtype had a higher percentage of stromal CD20+, intratumoral CD3+ tumor-infiltrating lymphocytes, and CD68+ tumor-associated macrophages than the luminal (Luminal A and Luminal B) subtype. The stromal programmed cell death ligand 1 (PD-L1) +, intratumoral CD3+ tumor-infiltrating lymphocytes, CD163+ tumor-associated macrophages, and PD-L1+ were also more commonly found in grade III breast cancer than in grade I and II breast cancer, respectively. Human papillomavirus was found in 20.6% of breast cancer patients and 29.6% of non-malignant breast tumors. Human papillomavirus infection was nearly 10-fold more common in ER-positive than ER-negative breast cancer. A considerably high prevalence of triple-negative breast cancer was reported in our study, demanding additional research that includes identifying genetic predisposition factors. A significant association was found between the breast cancer subtype and stromal CD20+, intratumoral CD3+ tumor-infiltrating lymphocytes, and CD68+ tumor-associated macrophages. The stromal PD-L1+, intratumoral CD3+ tumor-infiltrating lymphocytes, CD163+ tumor-associated macrophages, and PD-L1+ were also associated with tumor grade. Our findings suggest an important impact of MMPs in breast cancer pathophysiology, particularly MMP-11. This study also showed no proof of a link between HPV infection and breast cancer; however, the finding that HPV was more prevalent in breast tumors that were ER-positive than ER-negative warrants further attention.
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    Cultural Characterization, Molecular Detection and In-Vitro Antibiotic Susceptibility Profile of Streptococcus equi subsp. Equi from Donkeys Suspected of Strangles in Central Ethiopia
    (Addis Ababa University, 2012-06-01) Manyahilushal Etana; Tesfaye Sisay
    Cultural characterization and molecular detection of Streptococcus equi subsp. equi from strangles suspected naturally infected donkeys was conducted in central Ethiopia from September 20 II to April, 2012 . Antibiotic susceptibility profile of the isolates was also studied. Basic bacteriology for isolation and characterization, PCR for genome detection and disc method for antibiotic susceptibility were used. A total of 87 donkeys were sampled. Out of these 21 (24.1 %) donkeys had only nasal discharge, 47 (54%) had both nasal discharge and swelling of either submandibular or retropharyngeal lymph nodes, 2 (2.3%) had parotid lymph node involvement, 12 (13.8%) had severe guttural pouch empyema and extended head and neck with strider breathing and also 5 (5 .8%) donkeys chondroid positive at postmortem. Young donkeys were affected with severe form of the disease, swelling of lymph nodes of the head region and guttural pouch empyema, than adults (p<0.05). Culturally, a total of 189 bacterial isolates belonging to II genera were obtained. These were Streptococcus spp. (42.3%), Staphylococcus spp. (18%), Neisseria spp. (1 .6%), Enterococcus spp. (10.1 %), Bacillus spp. (7.9%), COlynebaclerium spp. (4.8%), Rhodococcus spp. (2.1 %), Pasteurella spp. (5.8%), AClinomycels spp. (3.7%), Pseudomonas spp.( 2.1 %) and Proteus spp. (1.6%). Swab samples had contributed for the majority of the isolates (87.8%). The isolation rate of S. equi subsp. equi from aspirate samples was 40% being significantly (p<0.05) higher than swab samples 14%. The detection rate by PCR was 72% and 87% from swabs and aspirates samples, respectively. The molecular method was more sensitive (p<0.05) compared to cultural method . which was significantly (p<0.05) higher compared to cultural method. The in- vitro antibiotic susceptibility test of S. equi subsp. equi revealed that all isolates were found to be susceptible to ampicillin, gentamicin, chloramphenicol, norfloxacin, erythromycin, vancomycin, cephalothin, doxycycline, ceftriaxone and tetracycline; however, all of the isolates were resistant to sulphonamide, kanamycin and streptomycin. Despite its lack of sensitivity relative to PCR, cultme is of value because it definitively establishes infection. Routine use of both microbial culture and PCR analysis of samples maximize detection of S. equi subsp. equi. Aspirates, when possible, are the preferred sample to increase the sensitivity of both culture and PCR assays
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    Epidemiological and Molecular Characterization of Multi-Drug Resistant Gram-Negative Bacterial Isolates from Bloodstream Infections Among Patients Admitted at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia
    (Addis Ababa University, 2024-03) Daniel Beshah; Adey Desta; Tesfaye Sisay; Gurja Belay
    Bloodstream infections are the major causes of morbidity and mortality worldwide. Alarmingly, Gram-negative bacteria that produce beta-lactamase and carbapenemase are causes for the rapid global spread of multi-drug resistance (MDR), which significantly jeopardizes the efficacy of existing antimicrobial treatments. This research aimed to analyze the microbial profile, antimicrobial susceptibility, genomic diversity, and associated risk factors of Gram-negative bacteria in bloodstream infections. A cross-sectional study was conducted between September 2018 and March 2019 on 1486 bloodstream infection suspected patients. In addition to biochemical identification and antimicrobial susceptibility tests, PCR and WGS were conducted for ESBL, AmpC, MBL and carbapenemase producing resistance genes. The prevalence of bloodstream infection was 417 (28.06%), and the most prevalent bacterial species were Klebsiella pneumoniae (17.6%) and Acinetobacter spp. (11%). Culture positivity was associated with age below 6 years, ICU admission, length of admission > 5 days, temperature greater than 38 oC, instrument usage during medical care, chronic illness, and neonatal incubation. Multi-drug resistance was 95% where 56%, 32% and 7% of the isolates exhibited MDR, XDR, and PDR respectively. Klebsiella pneumoniae and Acinetobacter sp. showed the greatest rates of XDR (37%) and PDR (77%), respectively. Among the 231 phenotypically characterized isolates, 195 (84%) drug-hydrolyzing enzyme producers, 54% and 26% were ESBL and carbapenemase-producer, respectively. Again, Klebsiella pneumoniae was the highest drug-hydrolyzing enzyme-producer bacteria. 176 out of the 195 (76%) were PCR-confirmed resistant bacteria, of which ESBLs, MBLs, carbapenemase, and AmpC-BLs accounted for 53%, 22%, 20%, and 10%, respectively and blaCTX-M, blaFOXM, blaOXA-23, and blaNDM were the highest hits in Klebsiella pneumoniae, (75%), and Escherichia coli (24%). Out of the 142 whole genome sequenced isolates, 1604 genes categorized into 168 resistance classed were identified. A total of 1055 virulence genes were identified belonging to 133 types. The majority of AMR genes and virulent genes were observed in Klebsiella pneumoniae (40%) and E. coli (71%), respectively. Sul2 was the most prevalent gene (%), followed by blaCTX-M-15 (5%), and aph (3'')-Ib (5%). fimH (6%), iutA (6%), and traT (5%) were the most prevalent virulent genes. The most common ESBL producer genes were blaCTX-M-15 (7%) and blaTEM-1B (6%) and the most common AmpC genes were blaCMY-2 (2%) and blaCMY-6 (1%). The highest carbapenemase genes were blaOXA-23 (3%), blaOXA-66 (3%), blaNDM-1 (2%), and blaOXA-1 (2%). In 82 (58%) of the sequenced strains, eight types of gene mutations were identified: parC (30%), gyrA (30%), ramR (1%), rpoB (1%), ompK37 (45%), acrR (43%), and ompK36 (43%) with a total of 220 antimicrobial gene mutations and 956-point mutations. However, 22 (2%) of the mutations were frameshift mutations and the rest 934 were point mutations. Among the 142 drug-resistant strains, 103 (73%) have plasmid mlst, and 108 (76%) have plasmid genes. Resistance to disinfectants like benzalkonium chloride 77(52%) and cetylpyridinium chloride 77(52%) had OqxA 41(29%), OqxB 41(29%), and qacE 49(35%) disinfectant-resistant genes. Like other AMR genes, NICU (B6) still has the leading prevalence of disinfectant resistance genes (22%) followed by C/W (9%) and pediatric hematology (D7) (8%). The study showed AMR has become a significant health hazard of bloodstream infection that most affects neonatal and ICU patients. The alarming result of this study was 7% PDR bacteria. The NICU by ESBL and SICU, General surgery, and caesarian section units by Carbapenemase producer strains were affected. A high burden of ESBL and Carbapenemase was seen in this study The predominant ESBL, MBLs, and Carbapenemase genes were blaCTX-M, blaNDM, and blaOXA-23 respectively. Nine novel drug-resistant bacteria strains were identified. Surgical and inserted medical instruments are the main drug-resistant bacteria transmission roots. Carbapenemase and MBL drug-resistant genes were associated with NICU, general surgery, SICU, and C/S unit which needs infection prevention standard implementation.
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    Epidemiological and Molecular Characterization of Multi-Drug Resistant Gram-Negative Bacterial Isolates from Bloodstream Infections Among Patients Admitted at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia
    (Addis Ababa University, 2024-03) Daniel Beshah; Adey Desta; Tesfaye Sisay; Gurja Belay
    Bloodstream infections are the major causes of morbidity and mortality worldwide. Alarmingly, Gram-negative bacteria that produce beta-lactamase and carbapenemase are causes for the rapid global spread of multi-drug resistance (MDR), which significantly jeopardizes the efficacy of existing antimicrobial treatments. This research aimed to analyze the microbial profile, antimicrobial susceptibility, genomic diversity, and associated risk factors of Gram-negative bacteria in bloodstream infections. A cross-sectional study was conducted between September 2018 and March 2019 on 1486 bloodstream infection suspected patients. In addition to biochemical identification and antimicrobial susceptibility tests, PCR and WGS were conducted for ESBL, AmpC, MBL and carbapenemase producing resistance genes. The prevalence of bloodstream infection was 417 (28.06%), and the most prevalent bacterial species were Klebsiella pneumoniae (17.6%) and Acinetobacter spp. (11%). Culture positivity was associated with age below 6 years, ICU admission, length of admission > 5 days, temperature greater than 38 oC, instrument usage during medical care, chronic illness, and neonatal incubation. Multi-drug resistance was 95% where 56%, 32% and 7% of the isolates exhibited MDR, XDR, and PDR respectively. Klebsiella pneumoniae and Acinetobacter sp. showed the greatest rates of XDR (37%) and PDR (77%), respectively. Among the 231 phenotypically characterized isolates, 195 (84%) drug-hydrolyzing enzyme producers, 54% and 26% were ESBL and carbapenemase-producer, respectively. Again, Klebsiella pneumoniae was the highest drug-hydrolyzing enzyme-producer bacteria. 176 out of the 195 (76%) were PCR-confirmed resistant bacteria, of which ESBLs, MBLs, carbapenemase, and AmpC-BLs accounted for 53%, 22%, 20%, and 10%, respectively and blaCTX-M, blaFOXM, blaOXA-23, and blaNDM were the highest hits in Klebsiella pneumoniae, (75%), and Escherichia coli (24%). Out of the 142 whole genome sequenced isolates, 1604 genes categorized into 168 resistance classed were identified. A total of 1055 virulence genes were identified belonging to 133 types. The majority of AMR genes and virulent genes were observed in Klebsiella pneumoniae (40%) and E. coli (71%), respectively. Sul2 was the most prevalent gene (%), followed by blaCTX-M-15 (5%), and aph (3'')-Ib (5%). fimH (6%), iutA (6%), and traT (5%) were the most prevalent virulent genes. The most common ESBL producer genes were blaCTX-M-15 (7%) and blaTEM-1B (6%) and the most common AmpC genes were blaCMY-2 (2%) and blaCMY-6 (1%). The highest carbapenemase genes were blaOXA-23 (3%), blaOXA-66 (3%), blaNDM-1 (2%), and blaOXA-1 (2%). In 82 (58%) of the sequenced strains, eight types of gene mutations were identified: parC (30%), gyrA (30%), ramR (1%), rpoB (1%), ompK37 (45%), acrR (43%), and ompK36 (43%) with a total of 220 antimicrobial gene mutations and 956-point mutations. However, 22 (2%) of the mutations were frameshift mutations and the rest 934 were point mutations. Among the 142 drug-resistant strains, 103 (73%) have plasmid mlst, and 108 (76%) have plasmid genes. Resistance to disinfectants like benzalkonium chloride 77(52%) and cetylpyridinium chloride 77(52%) had OqxA 41(29%), OqxB 41(29%), and qacE 49(35%) disinfectant-resistant genes. Like other AMR genes, NICU (B6) still has the leading prevalence of disinfectant resistance genes (22%) followed by C/W (9%) and pediatric hematology (D7) (8%). The study showed AMR has become a significant health hazard of bloodstream infection that most affects neonatal and ICU patients. The alarming result of this study was 7% PDR bacteria. The NICU by ESBL and SICU, General surgery, and caesarian section units by Carbapenemase producer strains were affected. A high burden of ESBL and Carbapenemase was seen in this study The predominant ESBL, MBLs, and Carbapenemase genes were blaCTX-M, blaNDM, and blaOXA-23 respectively. Nine novel drug-resistant bacteria strains were identified. Surgical and inserted medical instruments are the main drug-resistant bacteria transmission roots. Carbapenemase and MBL drug-resistant genes were associated with NICU, general surgery, SICU, and C/S unit which needs infection prevention standard implementation.
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    Factors Influencing Loan Repayment Performance of Micro and Small Enterprise Borrowers Financed by Micro-finance Institution; The Case of Oromia Credit and Saving S.C (OCSSCO).
    (Addis Ababa University, 2018-01) Tesfaye Sisay; Degefe Duressa
    Microfinance institutions in Ethiopia are playing an important role in poverty reduction strategies initiated by the government of Ethiopia. These institutions have a mission of creating and facilitating credit and other financial schemes to enhance self-employment opportunities and poverty reduction. There have been challenges in the microfinance institutions’ regarding reducing the high rate of default by their clients specifically with micro and small enterprise borrowers. Thus, the study objective was to identify factors influencing the loan repayment performance of MSE’s financed by MFI, in the Case of Oromia Credit and Saving S.C (OCSSCO).To address the main objectives of the study, four zonal offices of Oromia credit and saving Share Company were selected for the study purpose. Accordingly, in order to achieve the objective 329 sample borrowers were selected from the total of MSE borrowers served by those selected MF zonal offices. The data were collected using a structured questionnaires, and interviews. The descriptive statistics analysis and probit regression model were employed to estimate the model and analyze the results of findings. The result shows that eight variables including constant: monitoring utilization of other members in a enterprises, loan disbursement timeliness, repayment schedule suitability, repayment trend on monthly basis, repayment trend in irregular basis supervision on monthly basis and training adequacy are found significantly influence loan repayment performance of borrowers. Thus, it is recommended that the lending institutes need to focus on monitoring loan utilization systems of borrowers and technical support needs of the target borrowers through delivering better awareness creation to organize the more viable borrowers, close supervision, and follow-ups and strengthening their internal and external weaknesses through better training.
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    Infectious Bursal Disease Viru : Outbreaks Investigation, Molecular Characterization and Development of Live Attenuated Vaccine Using Local Isolates
    (Addis ababa Universty, 2012-04-15) Senait Belete; Tesfaye Sisay
    This study was conducted on sample collected from different regions of the country, where infectious bursal disease (IDB) outbreaks were reported. Samples were processed both at National Veterinary Institute and University of Liverpool, United Kingdom, with the aims of molecular characterization of local isolates, analyzing genetic relatedness of IDB virus circulating in the country with currently produced vaccine and development of vaccine from local isolates. The nucleotide and deduced amino acid sequence for VP2 hypervariable region (HVR) of ten IBDV isolates collected from 2009 until 2011 was also determined by RT-PCR and sequencing, and compared with well characterised IBDV isolates worldwide. A total of 136 bursa sample were pulled into 44 samples. Bursa samples were processed and cultured onto both confluent primary CEF cell cultures as well as fully confluent established cell line (Vero). Viruses were isolated from 41 (93 .2%) samples out of the 44 pulled samples. All the (Vero). Viruses were isolated from 41 (93 .2%) samples out of the 44 pulled samples. All the isolates were grown and able to demonstrate CPEs on CEF cell cultures on the first passage Phylogenetically, Ethiopian IBDV isolates were from one of two genetic lineages: very virulent lBDV and variants of the classical attenuated vaccine strain (078). Nucleotide identity between Ethiopian vvIBDVs range between 0% to 2.6% over VP2 HVR. isolate was superior to the current commercially available vaccine. The adapted trial vaccine isolate was superior to the current commercially available vaccine. The adapted trial vaccineEthiopian vvIBDVs clustered phylogenetically with the African IBDV genetic lineage, independent of the Asian/European genetic. This indicates the circulating of vvIBDV among Ethiopian chickens. Classical variant strain (IBDV 06/10) was selected for adaptation trial using Vero cells. The 9th Vero passage local isolate was evaluated with the current NVI vaccine for immunogenicity and pathogenesity on chicken. The result showed that the adapted local isolate was superior to the current commercially available vaccine. The adapted trial vaccine induced significantly (P<0.05) higher mean antibody titre (3281.35± 101.43) compared to the cun'ently used vaccine strain (2784.12±92.34). The mean bursa weight from the unvaccinated control groups was 20.8±1.2 g while it was 3.6±O.l6g and 2.8±0.07g, respectively, for commercial vaccine and 9th passaged local isolate. Although the difference in the mean bursa weight between the vaccinated groups was not statistically significant (P>0.05), the difference in the mean bursal weight between control and vaccinated groups was statistically significant (P<0.05).
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    Innovative Biocontrol Strategies for Anopheline Mosquitoes: Exploring Synergistic Interactions between Bacillus cereus and Enterobacter Cloacae
    (Addis Abeba University, 2025) Michael Abera; Tesfaye Sisay
    The impact of anopheline mosquitoes on humans needs no introduction; being vectors of malaria in humans. While the pathogenesis of Plasmodium in the mosquito as an adult has been well documented, not much research has been conducted on the biocontrol on the larval stage of the mosquitoes to hinder the disease’s spread. Current methods to control the anopheline mosquitoes are chemical, using nonspecific insecticides. As such, biocontrol has become a more preferred avenue but a primary concern is the lack of persistence of said biocontrol methods in the administered environments. Ergo, the objective of this study was to evaluate the larvicidal and persistence effects of a combined formulation of the Bacillus cereus and Enterobacter cloacae bacterial species on mosquitoes to cull the Anopheles to prevent them from reaching their adult stage. Co-cultures of the bacteria were prepared and tested on insectarium bred larvae at three different concentrations (5, 7 and 10 mL), with singular bacterial cultures serving as controls. The results were the elimination of first instars or stopping their development entirely. At 7 mL and above, the biofilm produced by the bacteria prevented eggs from hatching and suffocated the young larvae. The persistence of the co-cultures at effective doses also exceeded the previously recorded limit of 14 days for B. cereus, with the upper limit being 27 days (seemingly related to the extent of biofilm expansion in containers). A carefully selected bacterial co-culture is therefore a feasible method of Anopheles biocontrol, with potential applications on targets like Culex and Aedes.
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    Isolation and Characterization of Lytic Bacteriophages from Various Sources in Addis Ababa Against Antimicrobial Resistant Diarrheagenic E. Coli Strains and Evaluate their Therapeutic Potentials
    (Addis Ababa University, 2023-10) Tamirat Salile; Tesfaye Sisay
    Escherichia coli is a common fecal coliform, facultative aerobic, gram-negative bacterium. Pathogenic strains of such microbe have evolved to cause diarrhea, urinary tract infection and septicemias. The emergences of antibiotic-resistance urged to find an alternative strategy. The use of lytic bacteriophages against the control of pathogenic E. coli in the clinics and different environmental setups (waste and drink water management) become an alternative therapy to antibiotic therapy. Thus, this study aimed to isolate and characterize the lytic bacteriophage from various sources in Addis Ababa and tested against antimicrobial resistant diahrrgenic E. coli strains and evaluates their therapeutic potentials under invitro conditions. A total of 14 samples were processed against six different diahrrgenic E. coli strains. Conventional culture and plaque analysis agar overlay method was conducted to recover lytic bacteriophage isolates. The phage isolates were characterized to determine their lytic effect, growth characteristics, host range activity and stability under different temperature and pH conditions. Phage isolates were identified by Scanning Electron Microscope (SEM), molecular techniques (PCR), and whole genome sequencing. Totally, 17 phages were recovered from 84 tested plates. Totally, 17 phages were recovered from 84 tested plates. Of the 17 phage isolates, 11(65%) were Myoviridae-like phages, 6 (35%) phage isolates were Podoviridae and Siphoviridae by morphology and PCR identification. Bacteriophage genome sequencing revealed that each bacteriophage has a linear double-stranded DNA genome. The GC content of phage genomes ranged from 43 to 54%, while their sizes ranged from 40,427 to 143,710 bp. The whole genome sequence analysis of 7 potent coliphages showed that phage isolates were taxonomically classified as 4 (57%) of Myoviridae phages and 3 (43%) of Siphoviridae phages. Based on the host range test, growth characteristics and stability test 7 potent phages were selected. These phages demonstrated better growth characteristics, including short latent periods, highest burst sizes, and wider host ranges, as well as thermal stability and the ability to survive in a wide range of pH levels. These phages' promising effect against AMR pathogens has raised the possibility of their use in biological control of bacterial infections.
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    Isolation and Characterization of Mycobacterial Species Causing Tuberculosis Lesions in Slaughtered Camels in Eastern Ethiopia
    (Addis Ababa University, 2011-06) Kaleab Zerom; Tesfaye Sisay; Gobena Ameni; Gezahaegne Mamo
    A cross sectional study was conducted on 293 apparently healthy camels slaughtered at Jigjiga. Harar, Aweday and Dire Dawa abattoirs between December 2010 and April 20 11, The objective of the study was to isolate and characterize Mycobacterial species causing tuberculous lesions III slaughtered camels through postmortem examination. mycobacteria logical culturing. and multiplex polymerase chain reaction (PCR). A prevalence or 12.3% (36 /293) was recorded on the basis of postmortem examination and the di afference was statistically significant in females (X'=7.474. 1'=0.006) and in poor body condition (X'~ 7.323, 1'=0.025) camels when compared to their counter parts. About 79.5% of tuberculous lesions were found in lungs and associated lymph nodes in thoracic cavity and 15.9% in the lymph nodes of the head indicating inhalation as principal route of infection .Of the 36 camels with gross suspicious TB lesion organs and tissues cultured mica bacterial growth was observed in 66.7% (24 /3 6). Genotyping of the 17 isolates using multiplex polymerase chain reaction identified 88.2% (15/ 17) of them as member of mycobacteria other than Mycobacterium liber calliopsis complex and only once as member of M)lcobaCleriul1l ,tuberculosis complex. The relatively higher isolate ion of nontuberculous mycobacteria from most of camel 1'B lesions in this study could indicate their pathogenic or opportunistic role in the pathology or camel 1'13 signifying the need to further examine these species as cause of came l 'I'll so as to c1kctively elucidate its pathology. and enhance the effort in the control 01' the disease. Key words: Camels, Genotyping, Mycobacterium tuberculosis complex. Nontuberculous mycobacteria, Prevalence, Tuberculosis
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    Isolation and Identification of Corynebacterium Pseudotuberculosis from Superficial Lymphlinodes of Sheep and Goat at Organic Export Abbatoir, Modjo Ethiopia
    (Addis Ababa University, 2012-06) Daniel Abebe; Tesfaye Sisay
    Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CL.J\), a disease characterized by the formation of suppurative abscesses, particularly in superficial and internal lymph nodes, and in internal organs in small ruminants. The present study was conducted from November to April 201 1/ 2012 only on the superficial lymph nodes and carcass of small ruminants. Out of 768 small ruminants slaughtered at Organic slaughterhouse during the study period, 82 (68 in goats and 14 in sheep) were found to have gross evidence of abscess or caseous lymphadenitis. The typical gross lesion is a discrete abscess distended by thick and often dry, greenish yellow or white, purulent exudates. The most frequent sites of abscesses in goats occurred in the periscapular, pretemporal and popliteal lymph node and carcass 34(5.5'10/0). 24(3.91 %),2(0.33%) and 8(1.30%) respectively. In sheep 7(4.54%) in the periscapular, 5(3.25%) in pretemporal and 0% in popliteal lymph node and 2(1.23%) abscess on carcass were found. The study indicated that in both species young animals are more in number than adult, however, caseous lymphadenitis was found to be higher in ad ult than young animals in both species. There was statistically significant difference in the occurrence of CLA between age groups (P<0.05 J. Out of 68 bacterial cutes from goats 18 and 50, pure and mixed colonies, respectively. livre obtained; while out of 14 bacterial cultures boom sheep 4 and 10, pure and mixed colonies, respectively, were obtained. Corynebacterium pseudotuberculosis isolates were obtained from S9 out of 82 collected abscessed lymph nodes and carcass. Bacterial colonies were identified on the basis of morphological characteristics, primary and secondary biochemical tests, i.e cablese, urease, trehalas, xylose, maltose, and glucose fermentation tests and reverse CAMP test (antagonistic hemolysis between C. pseudotuberculosis and Staphylococcus aureus). Isolates positive for catalase, urease, maltose, and glucose, but with inhibiting hemolysin of Soured' by phospholipase D of C. pseudotuberculosis and negative for trehalas, and xylose "ere considered as C. pseudotuberculosis. The susceptibility pattern of C. pseudotuberculosis to antimicrobial agents varied among isolates. Out of 59 isolates of C. pseudotuberculosis isolated from lesions of caseous lymphadenitis in goats and sheep were susceptible to the antibi optics norfloxacin, tetracycline, doxycycline HCl and kanamycin. Keywords: Antimicrobial agents; Caseous lymphadenitis; Corynebacterium pseudotuberculosis; Goat; Lymph nodes; Mixed colonies; Pure colonies; Sheep.
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    Isolation and Identification of Corynebacterium Pseudotuberculosis from Superficial Lymphnodes of Sheep and Goat at Organic Export Abbatoir, Modjo Ethiopia
    (2012-06) Daniel Abebe; Tesfaye Sisay
    Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), a disease characterized by the formation of suppurative abscesses, particularly in superficial and internal lymph nodes, and in internal organs in small ruminants. The present study was conducted from November to April 2011/ 2012 only on the superficial lymph nodes and carcass of small ruminants. Out of 768 small ruminants slaughtered at Organic slaughterhouse during the study period, 82 (68 in goats and 14 in sheep) were found to have gross evidence of abscess or caseous lymphadenitis. The typical gross lesion is a discrete abscess distended by thick and often dry, greenish yellow or white, purulent exudates. The most frequent sites of abscesses in goats occurred in the prescapular, prefemoral and poplitial lymph node and carcass 34(5.54%), 24(3.91%), 2(0.33%) and 8(1.30%) respectively. In sheep 7(4.54%) in the prescapular , 5(3.25%) in prefemoral and 0% in poplitial lymph node and 2(1.23%) abscess on carcass were found. The study indicated that in both species young animals are more in number than adult, however, caseous lymphadenitis was found to be higher in adult than young animals in both species. There was statistically significant difference in the occurrence of CLA between age groups (P<0.05). Out of 68 bacterial cultures from goats 18 and 50, pure and mixed colonies, respectively, were obtained; while out of 14 bacterial cultures from sheep 4 and 10, pure and mixed colonies, respectively, were obtained. Corynebacterium pseudotubrculosis isolates were obtained from 59 out of 82 collected abscessed lymph nodes and carcass. Bacterial colonies were identified on the basis of morphological characteristics, primary and secondary biochemical tests, i.e. catalase, urease, trehalose, xylose, maltose, and glucose fermentation tests and reverse CAMP test (antagonistic haemolysis between C. pseudotuberculosis and Staphylococcus aureus). Isolates positive for catalase, urease, maltose, and glucose, but with inhibiting β- haemolysin of S. aureus by pospholipase D of C. pseudotuberculosis and negative for trehalose, and xylose were considered as C. pseudotuberculosis. The susceptibility pattern of C. pseudotuberculosis to antimicrobial agents varied among isolates. Out of 59 isolates of C. pseudotuberculosis isolated from lesions of caseous lymphadenitis in goats and sheep were susceptible to the antibiotics norfloxacin, tetracycline, doxycyline HCl and kanamycine.
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    Isolation and Identification of Lactic Acid Bacteria from 'Qibe', A Traditionally Prepared Ethiopian Butter
    (Addis Ababa Univensity, 2012-06-01) Elias Walelign; Tesfaye Sisay
    'Qibe' is a traditionally prepared Ethiopian butter made by churning fully soured cow’s milk. In this study,’Qibe’ samples originating from different parts of the country (Gojjam, Sidamo, Jimma, Sheno and Wolega) and sold at Merkato butter market have been be used. The study focused on the isolation and identification of Lactic acid bacteria (LAB) from 'Qibe'. For this purpose, six different butter retail shops were chosen. LAB were isolated based on their Gram stain and catalase test reactions. They were identified to the genus level based on their growth difference at different temperature levels (10°C, 21° C, and 45°C), NaCl concentrations (4%, 6.5%), tolerance to 60°C for thirty minutes and their reaction to citrate utilization as their sole energy source. Accordingly, 56 typical isolates of lactic acid bacteria (LAB) were selected out of the 87 isolates from samples of cow's butter ('Qibe'). They were further classified in to 5 different genera: Pediococcus, Streptococcus, Lactobacillus, Enterococcus and Lactococcus(44.6%, 21.4%, 21.4%, 12.5% and 5.3%, respectively). The highest proportion of Pediococci (48%), Streptococci (41.6%) and Lactococci (50%) were identified from Sidamo , Wolega and Wolega isolates, respectively. An increment in the diversity of the LAB species was also noticed in aged/ripe (three different species of LAB in 1.5 month and 2 months old Gojjam and Wolega samples, respectively, as compared to only one species of LAB identified from a 2weeks old Sheno and Sidamo samples) butter than in fresh ' Qibe' samples. The results showed that Pediococcus, Streptococcus and Lactobacillus were the predominant genera in this traditionally produced butter. However, identification of this isolates to the species level and assessing the technological performance of thus predominant isolates is essential and needs further investigation
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    Isolation and Molecular Characterization of Campylobacter Jejuni and Campylobacter Coli Isolated from Ethiopian Dairy Supply Chain and Evaluation of their Associated Risk Factors and Antimicrobial Resistance
    (Addis Ababa University, 2024-03) Abera Admasie; Tesfaye Sisay
    Campylobacter is among the leading bacterial foodborne pathogens, causing a high foodborne disease burden worldwide. There is a limited information on the prevalence, risk factor, and whole genome sequencing of Campylobacter in Ethiopian milk and milk products in major milk sheds in Ethiopia. To this end, a cross-sectional study was carried out to isolate and characterize the genomic diversity,antimicrobial resistance patterns and associated risk factors of Campylobacter species from milk and dairy products collected from representative regional sites (Oromia, Amhara, and SNNP). in Ethiopia. A total of 1140 dairy food samples were collected in the dry and wet seasons of which 456 samples were used for seasonal comparison. Samples were tested for Campylobacter by following the ISO 10272-1:2017 standard and confirmed by PCR with Illumina MiSeq instrument (v3 600-cycle cartridge) for the paired-end sequencing run. Amrfinderplus_db NCBI was used to detect gyrA and 50S_L22_A103V gene mutations. NCBI Pathogen Detection database was used for the genomic similarity . A total of 141 Campylobacter isolates were tested for susceptibility to three antibiotics using a disk diffusion method.. The result indicated that Campylobacter was detected in 12% of tested food samples. The highest prevalence of Campylobacter jejuni and Campylobacter coli was found in raw milk (19%), followed by pasteurized milk (10 %) and cottage cheese (3%) (P<0.001). The prevalence did not differ significantly between the wet (20%) and dry (16%) seasons (P=0.27). However, there was a five times more chance of finding Campylobacter species in milk and milk products during the wet season than the dry season (COR = 4.5 (1.8-12), P = 0.002). in the Oromia region, Besides, 89% of the samples were contaminated with C. jejuni, and 11% with C. coli. Two different C. jejuni MLST sequence types, namely, ST 51 (clonal complex ST-443) and ST 2084 (clonal complex 353) were detected; they were clustered in different clades (B and C), respectively. Two ST 1628 and 2 ST 830 C. coli from clonal complex 828 were grouped into a single clade (C). Phenotypically, 89 %, 74%, and 57% of Campylobacter species were resistant to tetracycline, erythromycin, and ciprofloxacin respectively. Moreover, 43% of the tested isolates were resistant to more than two drugs. Genomically, ten isolates of 8 C. jejuni ST 2084 and 2 C. coli ST 1628 had a T86I mutation in the gryA gene, which is associated with resistance to Quinolone (ciprofloxacin), and all 14 C. jejuni carry 50S_L22_A103V gene, associated with resistance against Macrolide (erythromycin). Of these, all Campylobacter species carried CTD genes, chemotaxis-related genes (cheA, cheB, cheR, and cheY), and invasive genes (flaC, ciaB, and ciaC). We can conclude that 12% of Campylobacter species were present during the dry and wet seasons. The data also showed that , 43% of the isolates acquired more than two antibiotic resistance genes and a mutation was present in the 50S_L22_A103V and gryA genes in C. jejuni. The risk factor analysis showed that using warm water and soap for cleaning cow udders and teats on farms (AOR=0.3, P=0.023), filtering milk with a cloth, or plastic filter (AOR=0.065, P=0.005), and storing milk in an aluminum container (AOR=0.23, P=0.027) reduced the likelihood of detecting Campylobacter in raw milk. In contrast, Campylobacter detection was significantly higher in milk samples collected at collection centers with concrete floors (AOR=5.2, P=0.004). The odds of detecting Campylobacter in milk were 17 times greater (AOR=17, P=0.007) in milk processing facilities that did not calibrate a pasteurizer on an annual basis. Likewise,, having a separate refrigerator for milk storage reduced the occurrence of Campylobacter in retail (AOR=0.29, P=0.021). In conclusion, Compared to samples of pasteurized and cottage cheese, the raw milk was more contaminated. Additionally, a mutation was found in the 50S_L22_A103V and gryA genes of C. jejuni, and 43% of the isolates that were studied possessed more than two antibiotic resistance genes. Thus, understanding the genetic composition and prevalence of Campylobacter in the dairy supply chain may help identify potential contamination sources and create effective management plans that ensure the safety and caliber of dairy products.
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    Isolation and Molecular Characterization of Mycobacteria from Cattle Slaughtered at Adama Abattoir
    (Addis Ababa University, 2010-06-01) Fetlework Kebede; Tesfaye Sisay
    Bovine tuberculosis (BTB) is endemic in Ethiopia. and the epidemiological picture of the disease has not yet been established. Skin testing and abattoir-based detection of lesions are the main tools for studying the epidemiology of BTB. A cros sectional study was conducted on 960 cattle slaughtered at Adama abattoir in east Shoa zone of Oromia region to estimate its prevalence and characterize its causative agents. Detail postmortem examination and patholog:- . coring. bacteriological culturing. and multiplex polymerase chain reaction (PCR) were applied in this study. On the basis of gross lesions. the prevalence of BTB was 12.7% (122 /960) in cattle slaughtered at Adama abattoir. The caudal mediastinal lymph nodes constituted the most severely affected tissue (mean± SEM; 0.55 ± 0.81) followed by cranial mediastinal (0. 308 ± 0.060). and left bronchial (0.\33 ± 0.042) lymph nodes. Multivariable logistic regression analysis sho\wed that cattle between 9-12 years of age were at a higher risk of infection (OR = 6.43: Cl = 2.43. 17.04) with TB. The result of genus typing of the eleven isolates using multiplex PCR indicated seven non- mycobaclerium tuberculosis complex members and only one Mycobacterium tuberculosis complex member while the remaining three isolates did not show signal neither for thc Genus :mycobacterium nor for it species. In conclusion. the results of the present stud) have indicated that TB lesions wcre prevalent in tissues of cattle slaughtered at Adama aballoir while the predominant mycobacteria causing such lesions were mycobacteria which were not members of Mycobacterium tuberculosis complex. And hence. further identification and characterization of these mycobacteria is required.