| 1. |
- Abebe, Mihret, et al.
(författare)
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Spherical and Porous Particles of Calcium Carbonate Synthesized with Food Friendly Polymer Additives
- 2015
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 15:8, s. 3609-3616
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Tidskriftsartikel (refereegranskat)abstract
- Porous calcium carbonate particles were synthesized by adding solutions of Ca2+ to solutions of CO32- containing polymeric additives. Under optimized conditions well-defined aggregates of the anhydrous polymorph vaterite formed. A typical sample of these micrometer-sized aggregates had: a pore volume of 0.1 cm(3)/g, a pore width of similar to 10 nm, and a specific surface area of similar to 25-30 m(2)/ g. Only one mixing Order (calcium to carbonate) allowed the formation of vaterite, which was ascribed to the buffering capacity and relatively high pH of the CO32- solution. Rapid addition of the calcium chloride solution and rapid stirring promoted the formation of vaterite, due to the high supersaturation levels achieved. With xanthan gum, porous and micrometer-sized vaterite aggregates could be synthesized over a wide range of synthetic conditions. For the Other food grade polymers, hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and sodium carboxyl methylcellulose, several intensive and extensive synthetic parameters had to be optimized to obtain pure vaterite and porous aggregates. HPMC and MC allowed well-defined spherical micrometer-sited particles to form. We expect that these spherical and porous particles of vaterite could be relevant to model studies as well as a controlled delivery of particularly large molecules.
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| 2. |
- Birhanu, Muluken, et al.
(författare)
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Antimicrobial susceptibility in Neisseria gonorrhoeae and epidemiological data of gonorrhoea patients in five cities across Ethiopia, 2021-22
- 2024
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Ingår i: JAC-antimicrobial resistance. - : Oxford University Press. - 2632-1823. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global public health concern and enhanced global gonococcal AMR surveillance is imperative. As in many African countries, regular, representative and quality-assured gonococcal AMR is lacking in Ethiopia. We describe the AMR in gonococcal isolates from five cities across Ethiopia, 2021-22, and patient epidemiological data.METHODS: Urethral discharge from males and cervical discharge from females were collected from October 2021 to September 2022. Epidemiological data were collected using a questionnaire. MIC determination (ETEST; eight antimicrobials) was performed on gonococcal isolates and EUCAST breakpoints (v13.1) were used.RESULTS: From 1142 urogenital swab samples, 299 species-identified gonococcal isolates were identified; 78.3% were from males and 21.7% from females. The median age for males and females was 25 and 23 years, respectively. Most isolates (61.2%) were identified in Addis Ababa, followed by Gondar (11.4%), Adama (10.4%), Bahir Dar (10.0%) and Jimma (7.0%). The resistance level to ciprofloxacin, tetracycline and benzylpenicillin was 97.0%, 97.0% and 87.6%, respectively, and 87.6% of isolates were producing β-lactamase. All isolates were susceptible to ceftriaxone, cefixime, azithromycin and spectinomycin. Recommended therapy [ceftriaxone (250 mg) plus azithromycin (1 g)] was used for 84.2% of patients.CONCLUSIONS: We present the first national quality-assured gonococcal AMR data from Ethiopia. Resistance levels to ciprofloxacin, tetracycline and benzylpenicillin were exceedingly high. However, all isolates were susceptible to ceftriaxone, cefixime, azithromycin and spectinomycin. In Ethiopia, it is essential to strengthen the gonococcal AMR surveillance by including further epidemiological data, more isolates from different cities, and WGS.
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| 3. |
- Mulu, Andargachew, et al.
(författare)
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The challenges of COVID-19 testing in Africa : The Ethiopian experience
- 2021
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Ingår i: Pan African Medical Journal. - : Pan African Medical Journal. - 1937-8688. ; 38, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- Novel coronavirus disease (COVID-19) is spreading rapidly and creating a huge economic, social and public health challenge worldwide. Although currently an effective vaccine is ready, its distribution is limited, and hence the only currently available lever to reduce transmission is to identify and isolate individuals who are contagious. Thus, testing for SARS CoV-2 has a paramount importance. However, testing in many African countries including Ethiopia has multidimensional growing challenges. Here, we tried to identify, categorize and summarize the challenges of COVID19 testing in Africa from Ethiopian experience.
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| 4. |
- Worku, Seble, et al.
(författare)
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Bacterial profile of surgical site infection and antimicrobial resistance patterns in Ethiopia : a multicentre prospective cross-sectional study
- 2023
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Ingår i: Annals of Clinical Microbiology and Antimicrobials. - : BioMed Central (BMC). - 1476-0711. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Globally, surgical site infections (SSI) are the most commonly reported healthcare-associated infections.Methods A multicentre study was conducted among patients who underwent surgical procedures at four hospitals located in Northern (Debre Tabor), Southern (Hawassa), Southwest (Jimma), and Central (Tikur Anbessa) parts of Ethiopia. A total of 752 patients clinically studied for surgical site infection were enrolled. The number of patients from Debre Tabor, Hawassa, Jimma, and Tikur Anbessa, hospitals was 172, 184, 193, and 203, respectively. At each study site, SSI discharge culture was performed from all patients, and positive cultures were characterized by colony characteristics, Gram stain, and conventional biochemical tests. Each bacterial species was confirmed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI TOF). An antimicrobial susceptibility test (AST) was done on Mueller-Hinton agar using the disk diffusion method. Logistic regression analysis was used to assess associations of dependent and independent variables. A p-value < 0.05 was considered statistically significant. Data were analysed using STATA 16 software.Results Among 752 wound discharge cultures performed, 65.5% yielded growth. Among these, 57.9% and 42.1% were Gram-negative and Gram-positive isolates, respectively. In this study, a total of 494 bacteria were isolated; Staphylococcus aureus (31%), Escherichia coli (20.7%), and Klebsiella pneumoniae (9.8%) were the most common. Rare isolates (0.8% each) included Raoultella ornithinolytica, Stenotrophomonas maltophilia, Alcalignes faecalis, Pantoea ecurina, Bacillus flexus, and Paenibacillus tylopili. Enterobacteriaceae showed high levels of resistance to most of the tested antibiotics but lower levels of ertapenem (32.9%), amikacin (24.3%), imipenem (20.3%), and meropenem (17.6%) resistance. Multidrug-resistant (MDR) frequency of Enterobacteriaceae at Debre Tabor, Hawassa, Jimma, and Tikur Anbessa hospitals was 84.5%, 96.5%, 97.3%, and 94%, respectively. Ages >= 61 years (AOR = 2.83, 95% CI: 1.02-7.99; P 0.046), prolonged duration of hospital stay (AOR = 4.15, 95% CI: 2.87-6.01; P 0.000), history of previous antibiotics use (AOR = 2.83, 95% CI: 1.06-2.80; P 0.028), history of smoking (AOR = 2.35, 95% CI: 1.44-3.83; P 0.001), emergency surgery (AOR = 2.65, 95% CI: 1.92-3.66; P 0.000), and duration of operation (AOR = 0.27, 95% CI: 0.181-0.392; P 0.000) were significant risk factors.Conclusion The most prevalent isolates from Gram-positive and Gram-negative bacteria across all hospitals were S. aureus and E. coli, respectively. Many newly emerging Gram-negative and Gram-positive bacteria were identified. Variation between hospitals was found for both SSI etiology type and MDR frequencies. Hence, to prevent the emergence and spread of MDR bacteria, standard bacteriological tests and their AST are indispensable for effective antimicrobial stewardship.
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| 5. |
- Worku, Seble, et al.
(författare)
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Molecular characterization of carbapenemase and extended spectrum beta-lactamase producing Acinetobacter baumannii isolates causing surgical site infections in Ethiopia
- 2024
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Ingår i: BMC Infectious Diseases. - : BioMed Central (BMC). - 1471-2334. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundAcinetobacter baumannii is an opportunistic pathogen that can cause a variety of nosocomial infections in humans. This study aimed to molecularly characterize extended-spectrum beta-lactamase (ESBL) producing and carbapenem-resistant Acinetobacter species isolated from surgical site infections (SSI).MethodsA multicentre cross-sectional study was performed among SSI patients at four hospitals located in Northern, Southern, Southwest, and Central parts of Ethiopia. The isolates were identified by microbiological methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility was determined using disk diffusion. The presence of phenotypic ESBL and carbapenemase production was detected by employing standard microbiological tests, including combined disk diffusion (CDT). ESBL and carbapenem resistance determinants genes were studied by polymerase chain reaction (PCR) and sequencing.ResultsA total of 8.7% Acinetobacter species were identified from 493 culture-positive isolates out of 752 SSI wounds. The species identified by MALDI-TOF MS were 88.4% A. baumannii, 4.7% Acinetobacter pittii, 4.7% Acinetobacter soli, and 2.3% Acinetobacter lactucae. Of all isolates 93% were positive for ESBL enzymes according to the CDT. Using whole genome sequencing 62.8% of the A. baumannii harbored one or more beta-lactamase genes, and 46.5% harbored one or more carbapenemase producing genes. The distribution of beta-lactamases among Acinetobacter species by hospitals was 53.8%, 64.3%, 75%, and 75% at JUSH, TASH, DTCSH, and HUCSH respectively. Among ESBL genes, blaCTX−M alleles were detected in 21.4% of isolates; of these 83.3% were blaCTX−M−15. The predominant carbapenemase gene of blaOXA type was detected in 24 carbapenem-resistant A. baumannii followed by blaNDM alleles carried in 12 A. baumannii with blaNDM−1 as the most common.ConclusionsThe frequency of Acinetobacter species that produce metallobetalactamases (MBLs) and ESBLs that were found in this study is extremely scary and calls for strict infection prevention and control procedures in health facilities helps to set effective antibiotics stewardship.
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| 6. |
- Worku, Seble, et al.
(författare)
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Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus among Patients Diagnosed with Surgical Site Infection at Four Hospitals in Ethiopia
- 2023
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Ingår i: Antibiotics. - : MDPI. - 2079-6382. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of severe surgical site infections (SSI). The molecular epidemiology of MRSA is poorly documented in Ethiopia. This study is designed to determine the prevalence of MRSA and associated factors among patients diagnosed with SSI. A multicenter study was conducted at four hospitals in Ethiopia. A wound culture was performed among 752 SSI patients. This study isolated S. aureus and identified MRSA using standard bacteriology, Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS), and cefoxitin disk diffusion test. The genes mecA, femA, vanA, and vanB were detected through PCR tests. S. aureus was identified in 21.6% of participants, with 24.5% of these being methicillin-resistant Staphylococci and 0.6% showing vancomycin resistance. Using MALDI-TOF MS for the 40 methicillin-resistant Staphylococci, we confirmed that 31 (77.5%) were S. aureus, 6 (15%) were Mammaliicoccus sciuri, and the other 3 (2.5%) were Staphylococcus warneri, Staphylococcus epidermidis, and Staphylococcus haemolyticus. The gene mecA was detected from 27.5% (11/40) of Staphylococci through PCR. Only 36.4% (4/11) were detected in S. aureus, and no vanA or vanB genes were identified. Out of 11 mecA-gene-positive Staphylococci, 8 (72.7%) were detected in Debre Tabor Comprehensive Specialized Hospital. Methicillin-resistant staphylococcal infections were associated with the following risk factors: age ≥ 61 years, prolonged duration of hospital stay, and history of previous antibiotic use, p-values < 0.05. Hospitals should strengthen infection prevention and control strategies and start antimicrobial stewardship programs.
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| 7. |
- Zelelie, Tizazu Zenebe, et al.
(författare)
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Molecular epidemiology and antimicrobial susceptibility of diarrheagenic Escherichia coli isolated from children under age five with and without diarrhea in Central Ethiopia
- 2023
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 18:7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Diarrhea is a serious health problem in children, with the highest mortality rate in sub-Saharan Africa. Diarrheagenic Escherichia coli (DEC) is among the major bacterial causes of diarrhea in children under age five. The present study aims to determine molecular epidemiology and antimicrobial resistance profiles of DEC and identify contributing factors for acquisition among children under age five in Central Ethiopia.METHODS: A health facility-centered cross-sectional study was conducted in Addis Ababa and Debre Berhan, Ethiopia, from December 2020 to August 2021. A total of 476 specimens, 391 from diarrheic and 85 from non-diarrheic children under age five were collected. Bacterial isolation and identification, antimicrobial susceptibility, and pathotype determination using polymerase chain reaction (PCR) were done.RESULTS: Of the 476 specimens analyzed, 89.9% (428/476) were positive for E. coli, of which 183 were positive for one or more genes coding DEC pathotypes. The overall prevalence of the DEC pathotype was 38.2% (183/476). The predominant DEC pathotype was enteroaggregative E. coli (EAEC) (41.5%, 76/183), followed by enterotoxigenic E. coli (21.3%, 39/183), enteropathogenic E. coli (15.3%, 28/183), enteroinvasive E. coli (12.6%, 23/183), hybrid strains (7.1%, 13/183), Shiga toxin-producing E. coli (1.6%, 3/183), and diffusely-adherent E. coli (0.6%, 1/183). DEC was detected in 40.7% (159/391) of diarrheic and 28.2% (24/85) in non-diarrheic children (p = 0.020). The majority of the DEC pathotypes were resistant to ampicillin (95.1%, 174/183) and tetracycline (91.3%, 167/183). A higher rate of resistance to trimethoprim-sulfamethoxazole (58%, 44/76), ciprofloxacin (22%, 17/76), ceftazidime and cefotaxime (20%, 15/76) was seen among EAEC pathotypes. Multidrug resistance (MDR) was detected in 43.2% (79/183) of the pathotypes, whereas extended spectrum ß-lactamase and carbapenemase producers were 16.4% (30/183) and 2.2% (4/183), respectively.CONCLUSION: All six common DEC pathotypes that have the potential to cause severe diarrheal outbreaks were found in children in the study area; the dominant one being EAEC with a high rate of MDR.
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