Vibrio cholerae O1 and Escherichia coli O157:H7 from drinking water and wastewater in Addis Ababa, Ethiopia.

BACKGROUND: In Addis Ababa, Ethiopia, open ditches along innner roads in residential areas serve to convey domestic wastewater and rainwater away from residences. Contamination of drinking water by wastewater through faulty distribution lines could expose households to waterborne illnesses. This prompted the study to assess the microbiological safety of wastewater and drinking water in Addis Ababa, identify the pathogens therein, and determine their antibiotic resistance patterns. RESULTS VIBRIO CHOLERAE: O1, mainly Hikojima serotype, was isolated from 23 wastewater and 16 drinking water samples. Similarly, 19 wastewater and 10 drinking water samples yielded Escherichia coli O157:H7. V. cholerae O1 were 100% resistant to the penicillins (Amoxacillin and Ampicillin), and 51-82% were resistant to the cephalosporins. About 44% of the V. cholerae O1 isolates in this study were Extended Spectrum Beta-Lactamase (ESBL) producers. Moreover, 26% were resistant to Meropenem. Peperacillin/Tazobactam was the only effective ß-lactam antibiotic against V. cholerae O1. V. cholerae O1 isolates showed 37 different patterns of multiple resistance ranging from a minimum of three to a maximum of ten antimicrobials. Of the E. coli O157:H7 isolates, 71% were ESBL producers. About 96% were resistant to Ampicillin. Amikacin and Gentamicin were very effective against E. coli O157:H7 isolates. The isolates from wastewater and drinking water showed multiple antibiotic resistance against three to eight antibiotic drugs. CONCLUSIONS: Open ditches for wastewater conveyance along innner roads in residence areas and underground faulty municipal water distribution lines could be possible sources for V. cholerae O1 and E. coli O157:H7 infections to surrounding households and for dissemination of multiple drug resistance in humans and, potentially, the environment.

Impact of school meals on educational outcomes in Addis Ababa, Ethiopia.

OBJECTIVE: This study evaluated the impact of the Addis Ababa School Feeding Program (SFP) on educational outcomes. DESIGN: Single-group repeated measurement/longitudinal study design and multistage stratified sampling design were followed. Effect sizes estimates, repeated measures ANOVA, Chi-square, Generalised Additive Mixed Model and mixed effects negative binomial regression were used. Academic scores, attendance and dropout and height and weight of schoolchildren were collected. SETTING: School Feeding Programs in Addis Ababa, Ethiopia. PARTICIPANTS: Schoolchildren in primary schools and school directors and teachers in fifteen randomly selected schools for Key Informant Interview (KII). RESULTS: Anthropometric measurements of 4500 schoolchildren were taken from 50 schools. Academic scores of 3924 schoolchildren from 46 schools, class attendance records of 1584 schoolchildren from 18 schools and annual enrolment records of 50 schools were gathered. School meals achieved a minimum to large scale effects on educational outcomes with effect sizes (η2) of academic scores (boys = 0·023, girls = 0·04), enrolment (girls = 0·001, boys = 0·05) and attendance (Cramer's V = 0·2). The average scores of girls were significantly higher than that of boys (P < 0·0001). Height-for-age in all schoolchildren (P < 0·01) and BMI-for-age Z-scores in adolescent girls of 15-19 years (P < 0·0001) never had a significant positive relationship with average scores. Significant relation was observed between nutritional status and attendance (P = 0·021). KII showed that SFP created convenient teaching-learning environment and reduced hunger in schools, while boosting enrolment, attendance and academic performance among the schoolchildren. CONCLUSION: The Addis Ababa SFP has positively contributed to educational outcomes. Strengthening the program would enhance nutritional outcomes and diminish educational inequalities.

Development of a defined mixed starter culture for the improvement of Tej, Ethiopian honey wine.

Ethiopian honey wine, Tej, is the most popular traditionally fermented alcoholic beverage in Ethiopia. Owing to the spontaneous fermentation process, the final product is neither predictable nor consistent in quality. Attempts have not been made before to solve this problem. Thus, the aim of this study was to develop a potential mixed starter culture of yeast and lactic acid bacteria isolated from Tej samples for the production of Tej with consistent quality. One hundred seventy-seven lactic acid bacteria and 194 yeasts were isolated from 30 Tej samples collected from southwest Ethiopia. After sequentially testing the isolates towards physiological stress tolerance and desired metabolic products, 10 lactic acid bacteria and 10 yeast isolates were screened. Later, four lactic acid bacteria and four yeast isolates were found to be compatible in co-culture tests. Finally, the combination of lactic acid bacteria and yeast isolates was formulated using the design of expert version 7.0.0 software, and six formulates (F #1-6) were designed. Controlled Tej fermentation was performed under laboratory conditions using six lactic acid bacteria-yeast starter culture formulations. The sensory attributes, in terms of color, flavor, odor, turbidity, and overall acceptance analysis scored 4.8/5.0 (F #2) and 4.7/5.0 (F #6), with mean significant variations (p < 0.05) among the other formulates. These two formulates were considered the best-mixed starter cultures compared to the control and other formulates. Matrix-assisted laser desorption ionization-time of flight analysis revealed that the lactic acid bacteria starters (AAUL7 and AAUL10) belonged to Lactobacillus paracasei. While the yeast starters (AAUY2 and AAUY8) belonged to Saccharomyces cerevisiae. These mixed lactic acid bacteria-yeast starter cultures could be used as the best starter culture for the fermentation of Ethiopian honey wine, Tej, with consistent quality.

Microbial, physicochemical and proximate analysis of Tej collected from Amhara regional state of Ethiopia.

Tej is an Ethiopian traditional alcoholic beverage with significant social and economic importance. Due to the spontaneous fermentation process of Tej, several issues such as safety, quality, and physicochemical properties of the final products is rquired to be assessed. Thus, this study was aimed to assess the microbial quality, physicochemical, and proximate properties of Tej associated with different maturity time. The microbial, physicochemical and proximate analyses were carried out by standard protocol. Lactic acid bacteria (6.30 log CFU/mL) and yeast (6.22 log CFU/mL) were the dominat microorganisms of all Tej samples at different maturity time, with significant differences (p = 0.001) in mean microbial count among samples. The mean pH, titratable acidity and ethanol content of Tej samples were 3.51, 0.79 and 11.04% (v/v), respectively. There were significant differences (p = 0.001) among the mean pH and titratable acidity values. The mean proximate compositions (%) of Tej samples were as follows: moisture (91.88), ash (0.65), protein (1.38), fat (0.47) and carbohydrate (3.91). Statistically significant differences (p = 0.001) were observed in proximate compositions of Tej samples from different maturity time. Generally, Tej maturity time has a great impact on the improvement of nutrient composition and the increment of the acidic contents which in turn suppress the growth of unwanted microorganisms. Further evaluation of the biological, and chemical safety and development of yeast-LAB starter culture are strongly recommended to improve Tej fermentation in Ethiopia.

School feeding contributed valuable dietary energy and nutrients despite suboptimal supply to school-age children and adolescents at primary schools in Addis Ababa, Ethiopia.

OBJECTIVES: This study investigated the nutritional quality and adequacy of school meals served to school-age children and adolescents. METHODS: A total of 55 food samples were collected from 11 food types served for breakfast and lunch at 15 selected school kitchens. Each meal was weighed using a digital scale. The initial sample weights were recorded and dried in an oven at a temperature of 60°C to constant weight. The nutrient content and dietary energy of the meals were calculated using a conversion factor with reference to the national food composition table. RESULTS: School meals supplied 883 calories of average energy, representing 48% and 34% of the daily recommended nutrient intake (RNI) for early adolescents (ages 7-12 y) or late adolescents (ages 13-17 y), respectively. Late-adolescent boys acquired the least RNI (31%). The meals contributed protein (44%-66%; 31%-47%), carbohydrate (50%-68%; 35%-48%), fat (15%-26%; 10%-20%), and fiber (44%-110%; 31%-78%) for early and late adolescents, respectively. Micronutrients, such as ß-carotene (36%-51%; 26%-37%), thiamine (47%-78%; 33%-54%), riboflavin (35%-55%; 26%-38%), niacin (16%-27%; 12%-19%), phosphorous (27%-41%; 20%-29%), calcium (64%-103%; 46%-73%), and iron (188%; 133%) were served for early and late adolescents, respectively. The caloric and nutritional contributions were generally less than two-thirds of the daily RNIs required from school meals, except that of fiber, thiamine, and calcium (for early adolescents), and iron. CONCLUSIONS: Despite their benefit to alleviate hunger in schools, school meals contributed suboptimal energy and nutrients to deprived school-age children and adolescents. Inclusion of animal products, fruits, and vegetables may improve energy and nutritional values.

Use of modified composite index of anthropometric failure and MUAC-for-age to assess prevalence of malnutrition among school-age children and adolescents involved in the school feeding program in Addis Ababa, Ethiopia.

BACKGROUND: Malnutrition hampers educational performance of schoolchildren coming from low-income families. School feeding program was, thus, launched in public primary schools in Addis Ababa very recently. It is, thus, important to measure the initial nutritional status of participating students to see the effect of the program on their nutritional wellbeing. METHODS: The first-round survey was made at the initiation of the program. A multi-stage stratified sampling from 50 schools located in the ten sub cities of Addis Ababa yielded 4500 children and adolescents of ages five to 19 years. Data was collected on age, height, weight and MUAC of the schoolchildren. Nutritional status was evaluated using conventional anthropometric indicators, modified Composite Index of Anthropometric Failure (mCIAF), and MUAC-for-age. Receiver Operating Characteristic (ROC) curve was used to examine classification of malnourishment by MUAC-for-age versus BMI-for-age and mCIAF versus MUAC-for-age. Multilevel mixed effects model was applied to investigate variations in the prevalence of malnutrition across sub cities. FINDINGS: The area under the ROC curves (AUC) for MUAC-for-age against BMI-for-age z-scores was 0.68 and that of mCIAF against MUAC-for-age was 0.70, respectively, indicating an overall better classification of malnourishment. Mixed effects model showed significant variations in nutritional status of schoolchildren across sub cities. Conventional measures showed that prevalence of stunting, thinness, or underweight among the sample children and adolescents was 23.4, 18.4, and 16.5%, respectively. Assessment by mCIAF, instead, showed a higher prevalence of overall malnutrition (43.4%). MUAC-for-age indicated an acute malnutrition measurement of 33.4%. Significant differences (p < 0.0001) in nutritional status were seen between boys and girls, and among age groups as measured by mCIAF. INTERPRETATION: Conventional measures of nutritional status undermined level of malnutrition. Instead, mCIAF and MUAC-for-age gave higher estimates of the magnitude of the existing prevalence of malnutrition among the school children and adolescents.

Distribution of drug resistance among enterococci and Salmonella from poultry and cattle in Ethiopia.

Enterococci and Salmonella were isolated from feces of chicken in intensive poultry farms and cattle which are maintained following traditional practices. Their resistance to different antibiotics was also determined. A total of 298 enterococcal isolates consisting of Enterococcus faecium (49.6%), Enterococcus durans (26.9%), Enterococcus hirea (11.9%), and Enterococcus faecalis (11.5%) were obtained. Among the enterococci, resistance to erythromycin (Ery), clindamicin (Cli), amoxicillin (Amo), ampicillin (Amp), and cephalothin (Cep) was high. Resistance to vancomycin (Van) was detected in all enterococcal species. Over 80% of the isolates showed multiple drug resistance. The most dominant patterns in poultry were Amo/Amp/Cep/Pen and Amo/Amp/Cep/Cli/Pen/Van. Among isolates from cattle, Amo/Amp/Cep/Cli/Ery/Pen/Van and Amo/Amp/Cli/Ery/Pen/Van constituted the most dominant multiple resistance patterns. A total of 51 Salmonella isolates were obtained from poultry (43/280) and cattle (8/450). About 70% of the isolates had varying resistance to the tested antibiotics. Multiple drug resistance was observed in over 30% of the Salmonella isolates. The most frequent resistance pattern was Amo/Amp/Cip/Gen/Str in cattle and Amo/Amp/Cep/Cip/Gen/Kan/Str in poultry. Enteroccoccal and Salmonella isolates showed multiple resistance to those antibiotics used in human and veterinary medicine. The high frequency of isolation of resistant enterococci is indicative of the wide dissemination of antibiotic resistant bacteria in the farm environment.

Fate of Escherichia coli O157:H7 during the processing and storage of Ergo and Ayib, traditional Ethiopian dairy products.

The long-term survival of E. coli O157:H7 in acid foods is well documented. This prompted us to evaluate the organism's survival during the making of Ergo, a traditional Ethiopian sour milk and Ayib, a traditional Ethiopian cottage cheese and during storage of these products at both ambient and refrigeration temperatures. E. coli O157:H7 test strains were separately inoculated into milk at initial levels of log10 3 cfu/ml. Levels of E. coli O157:H7 in the absence of lactic acid bacteria (LAB) reached log10 8.4 cfu/ml at 24 h as the pH dropped to 5.6 +/- 1.0. In milk inoculated with LAB (log10 6.4 cfu/ml) and E. coli O157:H7 (log10 3 cfu/ml), levels of LAB were log10 9.6 cfu/ml and 9.4 cfu/ml at 24 h and 72 h, respectively, and the pH values were 3.5 and 3.9, respectively. In the presence of LAB, E. coli O157:H7 grew to log10 6.5 cfu/ml at 24 h, with the levels decreasing to log10 3.2 cfu/ml at 72 h. Post-fermentation inoculation of E. coli O157:H7 in Ergo at an initial level of log10 3 cfu/ml, resulted in complete elimination of test organisms at 6 h at ambient temperature storage, but they were recovered until 72 h at refrigerated storage. At a higher initial inoculum level (log10 6 cfu/ml) of the E. coli O157:H7, the counts decreased by 4 logs within 12 h (pH 4.2) at ambient temperature storage, and complete elimination was observed at 36 h (pH 4.0). At refrigeration temperature, counts at 72 h were between 2.2 and 3.5 log cfu/ml for the different strains. During Ayib processing, E. coli O157:H7 in souring milk increased by 3 logs in 24 h, with a slight reduction being observed at 36 h. The pH dropped to 4.3 during this time. The numbers of E. coli O157:H7, immediately after curd cooking, were below detectable levels, but could be recovered by enrichment. Complete inactivation was observed on 24 h after curd cooking. When E. coli O157:H7 was inoculated into steam-treated Ayib (pH 4.2-4.3) at levels of log10 6.0-6.7 cfu/g and maintained at ambient temperatures, there was a gradual decrease in numbers to 3.7-4.3 logs by day 3. After day 7, pH values were 3.8-3.9 and E. coli O157:H7 was only detectable after enrichment. E. coli O157:H7 strain MF-1847 was completely inactivated by day 9, but the other two strains could still be recovered by enrichment at this time. At refrigeration storage, decrease in count of the test strains was gradual and counts at day 8 and 9 were >4 log cfu/g. As Ergo is preferably consumed soon after (24 h) fermentation, traditional fermentation of Ergo would not guarantee that E. coli O157:H7 can be controlled and, therefore, Ergo can be a potential health hazard if prepared from milk contaminated with E. coli O157:H7.

Microbial load, prevalence and antibiograms of salmonella and Shigella in lettuce and green peppers.

BACKGROUND: Human food borne infections traditionally are acquired through the ingestion of foods of animal origin. Fresh fruits and vegetables are major vehicles for the transmission of the food-borne infections. In Ethiopia, there is a tradition of consuming raw vegetables, particularly lettuce and green pepper, without adequate treatment. The objective of this study was to investigate the microbial load of fresh lettuce and green pepper, used as salad vegetables, and to assess the prevalence and antibiotic resistance of Salmonella and Shigella spp. isolated from lettuce and green pepper. METHODS: A total of eighty samples of lettuce and green peppers were purchased from different outlets in Addis Ababa and analyzed for their load of various microbial groups and flora analysis was conducted following standard microbiological methods. The presence of Salmonella and Shigella and their antibiotic resistance was also determined. RESULTS: Over 90% of the vegetable samples had aerobic mesophilic counts of ≥ log 6 cfu/g. Ninety seven percent of the lettuce and 58% of the green pepper samples had enterobacteraceae counts of ≥ log 5 cfu/g. Coliforms were encountered at counts ≥ log 4 cfu/g in 48% and 35% of lettuce and green pepper samples, respectively. Over 80% of vegetable samples harbored staphylococci with counts ranging from log 4 to log 6 cfu/g. More than 88% of lettuce and 18% of green pepper samples had yeast and mold counts ≥ log 4 cfu/g. The aerobic mesophilic flora of the vegetable samples was dominated by Bacillus and Micrococcus spp. Salmonella and Shigella were isolated from eight (10%) and 24 (30%) samples, respectively. All of the Salmonella and 97% of Shigella isolates showed resistance to penicillin. Ampicillin resistance was observed in 42% of Salmonella and 79% of Shigella isolates. Multiple drug resistance was seen in 8 and 24 isolates of Salmonella and Shigella isolates, respectively. CONCLUSION: The majority of lettuce and green pepper samples had high microbial load and multiple drug resistant pathogens were also isolated from some samples. As lettuce and green pepper, when used as salad vegetables, do not get any further heat treatment, thorough washing and considerably longer exposure of the vegetables to food grade chemicals is recommended to kill pathogens and significantly reduce the microbial load.

Yeast and lactic acid flora of tej, an indigenous Ethiopian honey wine: variations within and between production units.

A total of 200 samples of tej, an indigenous Ethiopian honey wine, were collected from ten production units at different production times. The samples were analysed for their microbial flora. Mean counts of aerobic mesophilic bacteria and aerobic spores for the different production units were <3 log cfu/ml. Coliforms and other members of Enterobacteriaceae were below detectable levels basically due to the low pH of the samples (<4.0). Yeasts were among the dominant micro-organisms in all samples with mean counts of 6 log cfu/ml for all production units. Over 25% of the yeast isolates belonged to Saccharomyces cerevisiae followed by Kluyvermyces bulgaricus (16%), Debaromyces phaffi (14%) and K. veronae (10%). Yeast counts showed significant variation within samples of a production unit (CV>10%) and difference in counts among all samples was also significant (P<0.01). The lactic acid bacteria had counts of 6 log cfu/ml with a significant variation within samples of a production unit (CV>10%) or among all samples (P<0.01). In most production units, the heterolactics had higher counts than the homolactics. The lactic flora consisted of Lactobacillus, Streptococcus, Leuconostoc and Pediococcus species. The lactobacilli were, however, the most frequently encountered groups. In most of the samples, the lactic flora was dominated by two (49.5%) or three (46%) groups of lactic acid bacteria.

Growth and survival of Escherichia coli O157:H7 in fresh tropical fruit juices at ambient and cold temperatures.

The survival of Escherichia coli O157:H7 in acidic foods and its enhanced survival in refrigerated acid foods are well documented. This prompted the present study to evaluate the growth potential of E. coli O157:H7 in fresh tropical fruit juices. The pH of the various juices ranged between 3.57 (pineapple) and 6.2 (avocado). Samples were separately inoculated with a mixture of four E. coli O157:H7 strains at initial levels of approximately 10(3) cfu/ml, and stored at refrigeration (4 degrees C) and ambient (20-25 degrees C) temperatures for 120 h. In pineapple juice, some decline in count was noted during ambient temperature storage but complete inhibition was not observed. At refrigeration temperature, the test strains survived without a noticeable decline in number. The pH remained unchanged throughout the experiment at both incubation temperatures. In papaya and avocado juices, counts of the test strains increased at varying rates at both storage temperatures. A decrease in pH was also noted in the stored juice. This study demonstrated that E. coli O157:H7 can survive well in acidic pineapple juice at both incubation temperatures and could also grow luxuriously in fruit juices with relatively higher pH values (>5.7) when stored at ambient and refrigeration temperatures.

Inhibitory Effect of Lactobacillus plantarum on Salmonella infantis , Enterobacter aerogenes and Escherichia coli during Tempeh Fermentation.

Growth and inhibition of Salmonella infantis , Enterobacter aerogenes and Escherichia coli in fermenting soybeans during tempeh production were studied in presence and absence of Lactobacillus plantarum . In fermenting unacidified soybeans S. infantis grew by 7 log units in 40 h. E. coli and E. aerogenes grew by 6 and 7 log units respectively. A similar pattern of growth of the three test organisms in fermenting acidified beans was also noted. Further inoculation of unacidified cooked beans with L. plantarum at a level of 106/g resulted in a complete inhibition of the test organisms in the product. On acidified cooked beans a lower level of L. plantarum inoculum (102/g) was enough to show a complete inhibitory effect. The lowering of the pH in fermenting beans by L. plantarum might have played a role in the destruction of the test organisms.