Microbial, Cellular and Molecular Biology

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Browsing Microbial, Cellular and Molecular Biology by Subject "Addis Ababa"

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    Microbial Quality and Safety Assessment of Fresh Lettuce in Addis Ababa, Ethiopia
    (Addis Ababa University, 2025-02-27) Yeabsera Damtew; Fitsum Tigu
    Lettuce is high in water content (94-95%) and low in calories. It's also high in vitamins, minerals, and bioactive substances including polyphenols, carotenoids, and chlorophyll, all of which have health benefits. Food-borne illness outbreaks linked to the consumption of ready-to-eat vegetables are on the rise. but the recent information about the microbial loads and safety aspects of fresh lettuce are lacking. In this study, the microbial quality and safety assessment of fresh lettuce in Addis Ababa, Ethiopia were investigated. The general objective was to assess the microbial quality and safety and identify the major food-borne pathogens from fresh lettuce samples collected from selected marketplaces in Addis Ababa. A stratified random sampling was used to select 110 vegetable sellers in Addis Ababa, Ethiopia. Detection of hygiene indicators microorganisms: total coliforms, aerobic mesophilic bacteria (AMB), yeast, mold and Enterococci, E. coli, and other food-borne pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, were analyzed from 110 fresh lettuce samples. The study reveals that the fresh lettuce samples collected from selected marketplaces in Addis Ababa were contaminated with various microorganisms, including total coliform, Staphylococci, Fecal streptococci and E. coli this indicates the poor hygienic conditions of the study area. As a confirmatory test, 33 positive representative isolates after the biochemical test were taken and detected by polymerase chain reaction (PCR). Among the analyzed samples, only 2 samples Addis Ketema and Lideta sub cities were positive for E. coli and P. aeruginosa, respectively. This contamination poses a potential biological health hazard to general consumers, as they are at risk of contracting food-borne infections. The findings underscore the urgent need for improved hygiene and safety measures in the production and handling of lettuce to safeguard consumers from potential biological health risks in Addis Ababa.
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    Mycobacterium Tuberculosis Infection Among Homeless Individuals in Addis Ababa, Ethiopia: Disease Burden, Drug Resistance Patterns and Molecular Epidemiology
    (Addis Ababa University, 2024-05) Tsegaye Shamebo; Beyene Petros; Gobena Ameni; Balako Gumi
    In high tuberculosis (TB) burden countries like Ethiopia, rapid screening and prompt treatment initiation among vulnerable groups, such as the homeless, are essential for TB control efforts. During the last three decades, Ethiopia has experienced a rise in homelessness, which is attributed to internal conflicts and economic stress. In spite of the fact that TB disproportionately affects homeless individuals, the majority of research conducted on it in Ethiopia has not adequately addressed the disease burden on this vulnerable group. This study aimed to determine the disease burden, molecular epidemiology, and drug resistance patterns of Mycobacterium tuberculosis (M. tuberculosis) among homeless individuals in Addis Ababa, Ethiopia. A cross-sectional study was conducted in Addis Ababa between February 2019 and December 2020. Homeless individuals underwent pulmonary tuberculosis (PTB) clinical screening according to WHO guidelines. Suspected cases provided sputum samples for acid-fast bacillus (AFB), Xpert MTB/RIF assay, TB culture, and drug sensitivity test (DST). The M. tuberculosis isolates were typed using Polymerase-Chain-Reaction (PCR) based Region of Difference-9 (RD9), spoligotyping, and 24-loci M. tuberculosis Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) typing. DST was performed using the BD Bactec Mycobacterial Growth Indicator Tube (MGIT) 960. Data analyses were performed using SPSS software version 26 and the M. tuberculosis complex (MTBC) online database. Out of 5,600 homeless individuals enrolled in the study and clinically screened for PTB symptoms, 641 suspected cases were identified. Thus, the clinical prevalence of PTB was 1054 per 100,000 homeless individuals. Being homeless for more than 5 years, a body mass index (BMI) < 18.5, smoking cigarettes, living in a group of more than 5 persons, close contact with chronic coughers, imprisonment, and HIV infections were significantly associated with the prevalence of PTB in the homeless (P < 0.05). Out of 59 isolates, 58 were confirmed as M. tuberculosis by the RD9 PCR test. Genotyping revealed three MTBC lineages and eight sub-lineages, with Euro-American lineage predominating. Furthermore, Spoligo International Types (SIT), SIT53, SIT37, and SIT149 were highly prevalent strains detected in this study. Ethiopia_3, Delhi/CAS and Ethiopia_2 were determined to be the most prevalent sub-lineages in the study population. Strain clustering rates were 77.6% using spoligotyping, 39.7% using 24-loci MIRU-VNTR typing, and 10.3% using a combination approach. Living in a group was significantly associated with strain clustering (P < 0.05). Three homeless individuals with PTB harbored mixed M. tuberculosis strains. DST revealed 6.8% (4/59) of isolates resistant to at least one first-line anti-TB drug. Overall, the prevalence of PTB in homeless individuals was higher than that in the general population of Addis Ababa. Therefore, governmental and non-governmental organizations working on TB prevention and control must consider homeless settings as hotspots for TB control. Regular PTB screening, directly observed treatment short course (DOTS) centers, and mobile clinics must be established to control TB among homeless individuals and its spread to the general population.
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    Prevalence of Salmonella and Shigella Spp on Lettuce and Green Pepper and their Drug Resistance Pattern
    (Addis Ababa University, 2008-07-03) Guchi, Biniam; Ashenafi, Mogessie (Professor)
    The microbial load of lettuce and green pepper purchased from different supermarkets in Addis Ababa, Ethiopia, was analyzed. A total of 80 vegetable samples consisting of 40 lettuces and 40 green peppers were included in the study. More than 90% of the lettuce and the green pepper samples had aerobic mesophilic counts of ≥ log 6 cfu/g. Enterobacteriaceae were frequently encountered in these samples and about 97% of the lettuce and 58% of the green pepper samples had enterobacteraceae counts of ≥ log 5 cfu/g. Over 48% of the lettuce and 35% of the green pepper samples had coliform counts ≥ log 4 cfu/g. All vegetable samples harbored staphylococci and more than 92% of the lettuce samples and 80% of the green pepper samples harbored staphylococci with counts ranging from log 4 to log 6 cfu/g. About 42% of lettuce and 30% of green pepper samples had spore counts ≤ log 2 cfu/g. The majority of lettuce and green pepper samples harbored yeasts and mold and more than 88% of lettuce and 18% of green pepper samples had counts ≥ log 4 cfu/g. The aerobic mesophilic flora of both lettuce and green pepper samples were dominated by Gram positive organisms, with Bacillus and Micrococcus being the most dominant species in the lettuce and green pepper, respectively. Salmonella was isolated from six (10%) samples consisting of two lettuce and four green pepper samples. Shigella was also isolated from fifteen (18.75%) samples of five lettuces and ten green peppers samples. Resistance to antibiotics was seen in all isolates from the vegetable samples. All of the Salmonella and 97% of Shigella isolates showed resistance to penicillin. The majority of the Salmonella isolates showed susceptibility to polymixin B., gentamicin and ciproflaxin. Ampicillin resistance was observed in 42% of Salmonella and 79% of Shigella isolates. Multiple drug resistance (MDR) was observed in 8 and 24 isolates of Salmonella and Shigella isolates.