Prevalence of Escherichia coli O157:H7 and associated factors in under-five children in Eastern Ethiopia

Antibacterial activity and multi-target mechanism of harmane against Escherichia coli O157:H7 and its application on ready-to-eat leafy greens

Escherichia coli O157:H7 has caused many foodborne disease outbreaks and resulted in unimaginable economic losses. With the evolution of food consumption, people prefer natural preservatives. In this study, the natural agent harmane exhibited potential activity against E. coli O157:H7 (MIC = 64 μg/mL). It exhibited bacteriostatic mode at 1 X and 2 X MIC treatment, and bactericidal mode at 4 X MIC treatment. Moreover, it showed good in vitro stability in sheep plasma, low in vitro hemolysis and no in vivo acute toxicity with LD50 > 50 mg/kg. Moreover, harmane significantly decreased the colony number of E. coli O157:H7 in fresh-cut lettuce samples after 5 days of storage without affecting appearance. The mechanism study elucidated that harmane significantly decomposed the mature biofilm by reducing exopolysaccharide contents, and killed the viable bacterial cells in biofilm. The cell wall was damaged by harmane via interacting with peptidoglycan. Fluorescent staining and intracellular macromolecular leakage assays showed that irreversible destruction to membrane permeability and integrity. When entering the cell, harmane could defeat the redox balance, suppress metabolic activity and target to ribosome. These findings not only revealed the application potential of harmane as new natural preservative, but also preliminarily elucidated the multi-target mechanism, providing a new strategy for controlling E. coli O157:H7 in the food industry.

Extended-Spectrum β-Lactamase and carbapenemase-producing Escherichia coli O157:H7 among diarrheic patients in Shashemene, Ethiopia

BACKGROUND

The worldwide increase in multidrug resistance is a major threat to public health. One particular concern is the presence of Escherichia coli strains that carry Extended-Spectrum β-Lactamase (ESBL) and Carbapenemase enzymes, which can make multiple antibiotics ineffective. This complicates treatment strategies and raises the risk of illness and death. The aim of this study was to isolate E. coli O157:H7, assess its susceptibility against antimicrobial agents, and determine the presence of ESBL and Carbapenemase production in stool samples collected from diarrheic patients in Shashemene, west Arsi, Ethiopia from July to November 2022.

METHODS

The samples were cultured McConkey Agar and E. coli were isolated and identified by standard biochemical tests using API 20E. E. coli O157:H7 was further identified using sorbitol McConkey Agar and antisera for O157 antigen test. The antimicrobial susceptibility test was performed using the Kirby-Bauer disc diffusion method using different antibiotics. Each identified isolate was screened and tested for phenotypical ESBL and Carbapenemase production using combined disc method and modified carbapenem inactivation method, respectively. Bivariant and multivariant analyses were employed using a logistic regression model for further analysis and were interpreted based on the odds ratio and level of statistical significance at a p-value <0.05 with 95% confidence interval.

RESULTS

E. coli O157:H7 strain was found from 9% (38/423) study participants. The majority of the participants [61.9% (262/423)] were males; and 19.1% (81/ 423) of the participants were under five children. Living in urban areas, having domestic animals, and ≥5 family size in the household were identified as statistically significant factors associated with E. coli O157:H7. Twenty-seven (71.1%) and 12 (31.6%) of the 38 E. coli O157:H7 isolates were phenotypically confirmed to be ESBL and carbapenemase producers, respectively. All isolates were resistant against Ampicillin, but sensitive to ciprofloxacin. High resistance to Ampicillin and Amoxicillin/Clavulanic acid was observed among the ESBL and carbapenemase producing isolates also. The extent of detection of multidrug resistant E. coli O157:H7 isolates against three or more classes of antimicrobial agents tested was alarmingly very high (84%).

CONCLUSION

The E. coli O157:H7 isolates in this study showed a significant resistance to certain antimicrobials that were tested. The level of ESBL and Carbapenemase production among these isolates was found to be quite high. We observed a high resistance to Ampicillin and Amoxicillin/Clavulanic acid among the ESBL and carbapenemase producing isolates. Ciprofloxacin was found to be the most effective drug against both the ESBL producers and nonproducers.

Exposure behaviour to Escherichia coli among households in Imvepi refugee settlement, Terego district Uganda

INTRODUCTION

Exposure to Escherichia coli (E. coli) is a risk factor for diarrhoeal diseases, which pose a significant problem in refugee settlements. Refugee populations are exposed to faecal microorganisms through multiple pathways including sub-optimal sanitary facilities, contaminated drinking water, produce and food, flood water, bathing water, and soil among others. While these pathways are well-documented, specific exposure behaviours remain underexplored. We assessed exposure behaviour to E. coli among households in Imvepi refugee settlement, Uganda, and provided evidence-based recommendations for the design of interventions to reduce excreta-related disease in refugee settlements.

METHODS

Guided by the Sanitation Safety Planning approach, we surveyed 426 households in Imvepi refugee settlement, Uganda, using a digitized questionnaire and an observation checklist. We collected data on the background characteristics and exposure behaviour of women and emancipated girls (minors living on their own, having borne a child, married, or pregnant). The outcome variable, E. coli exposure behaviour, was measured using a five-point Likert scale, assessing behaviours that increase the risk of exposure. Data were cleaned in Microsoft Excel and analyzed in Stata version 17. Descriptive statistics were performed to summarize the data. We used modified Poisson regression to determine the factors associated with the outcome.

RESULTS

Over 59.4% (253) exhibited high-risk exposure behaviour. Residing in compound homes (Adjusted Prevalence Ratio (APR) = 0.72, 95% Confidence interval (CI): 0.58-0.90), being aged 35-49 years (APR = 0.76, 95% CI: 0.60-0.97), having household heads with post-primary education (APR = 0.54, 95% CI: 0.38-0.77), high knowledge (APR = 0.69, 95% CI: 0.59-0.80), and high-risk perceptions regarding exposure to E. coli (APR = 0.75, 95% CI: 0.64-0.88) were associated with a lower prevalence of high-risk E. coli exposure behaviours. Conversely, having sanitary facilities with excreta overflowing from the squat hole (APR = 1.26, 95% CI: 1.08-1.48) was associated with a higher prevalence of high-risk exposure behaviours.

CONCLUSION

The study indicates a substantial prevalence of high-risk E. coli exposure behaviours in the refugee settlement.. There's a need to implement behaviour change interventions targeted at preventing or minimizing exposure, especially among households whose heads have low education attainment, those with young caretakers and those with limited knowledge and low-risk perceptions regarding exposure to E. coli.

Occurrence, molecular characterization, and antimicrobial susceptibility of sorbitol non-fermenting Escherichia coli in lake water, fish and humans in central Oromia, Ethiopia

Contaminated lake water and fish can be sources of bacterial pathogens of public health concern, including pathogenic E. coli. Within Ethiopia, specifically, Central Oromia, raw fish consumption is a common practice. Although there are few reports on occurrence of E. coli O157 in fish destined for human consumption and children under five years, information on the transmission pathways of E. coli O157 and other sorbitol non-fermenting (SN-F) E. coli from water-to-fish-to-human, and their virulence factors and antimicrobial resistant determinants along the fish supply chain is lacking. The study aimed to investigate the occurrence, molecular characteristics, and antimicrobial susceptibility of E. coli O157 and other SN-F E. coli strains in fish, lake water and humans in central Oromia, Ethiopia. A total of 750 samples (450 fish samples, 150 water samples, 150 human stool samples) were collected from five lakes and three health facilities. The samples were processed following the standard protocol recommended by European Food Safety Authority and Kirby-Bauer disc diffusion method for detection of the bacteria, and antimicrobial susceptibility tests, respectively. Molecular characterization of presumptive isolates was performed using Whole-Genome Sequencing (WGS) for serotyping, determination of virulence factors, antimicrobial resistance traits, and genetic linkage of the isolates. Overall, 3.9% (29/750) of the samples had SN-F E. coli; of which 6.7% (n = 10), 1.8% (n = 8) and 7.3% (n = 11) were retrieved from water, fish, and diarrheic human patients, respectively. The WGS confirmed that all the isolates were SN-F non-O157: H7 E. coli strains. We reported two new E. coli strains with unknown O-antigen from fish and human samples. All the strains have multiple virulence factors and one or more genes encoding for them. Genetic relatedness was observed among strains from the same sources (water, fish, and humans). Most isolates were resistant to ampicillin (100%), tetracycline (100%), cefotaxime (100%), ceftazidime (100%), meropenem (100%), nalidixic acid (93.1%) and sulfamethoxazole/trimethoprim (79.3%). Majority of the strains were resistant to chloramphenicol (58.6%) and ciprofloxacin (48.3%), while small fraction showed resistance to azithromycin (3.45%). Isolates had an overall MDR profile of 87.5%. Majority, (62.1%; n = 18) of the strains had acquired MDR traits. Genes encoding for mutational resistance and Extended-spectrum beta-lactamases (ESBL) were also detected. In conclusion, our study revealed the occurrence of virulent and MDR SN-F E. coli strains in water, fish, and humans. Although no genetic relatedness was observed among strains from various sources, the genomic clustering among strains from the same sources strongly suggests the potential risk of transmission along the supply chain at the human-fish-environment interface if strict hygienic fish production is not in place. Further robust genetic study of the new strains with unknown O-antigens, and the epidemiology of SN-F E. coli is required to elucidate the molecular profile and public health implications of the pathogens.

Shiga toxin-producing Escherichia coli O157:H7 among diarrheic patients and their cattle in Amhara National Regional State, Ethiopia

BACKGROUND

Shiga toxin-producing Escherichia coli O157:H7 (STEC O157:H7) is a zoonotic pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome worldwide. This study aimed to determine the prevalence, antibiotic susceptibility, and associated risk factors of STEC O157:H7 among diarrheic patients and their cattle.

METHODS

A cross-sectional study was conducted among diarrheic patients and their cattle in Amhara National Regional State, Ethiopia from December- 2020 to June- 2022. A total of 1,149 diarrheic patients and 229 cattle were included in the study. STEC O157:H7 detection was done using culture, latex agglutination test, and polymerase chain reaction on diarrheic stool samples and recto-anal mucosal swabs of cattle. Antibiotic susceptibility tests were performed using disk diffusion techniques. Risk factors association were identified using binary and multivariable logistic regression analysis.

RESULTS

The overall prevalence of STEC O157:H7 in diarrheic patients and their cattle was 11.1% (128/1149) and 14.4% (33/229) respectively. High percentage of the study subjects were found in under-five children (34.5%). Age less than 5 (AOR: 4.02, 95%CI:1.608-10.058,P = 0.003), and greater than 64 years old (AOR:3.36, 95% CI:1.254-8.986, P = 0.016), presence of diarrheic patient in the house (AOR:2.11, 95%CI:1.309-3.390, P = 0.002), availability of cattle in the house (AOR:2.52, 95%CI:1.261-5.049, P = 0.009), and habit of consuming raw foods (AOR:4.35, 95%CI:2.645-7.148, P = 0.000) were risk factors. Antibiotic resistance was shown in 109(85.2%), and 31(93.9%) isolates from diarrheic patients and their cattle respectively. The highest levels of antibiotic resistance were found to tetracycline (54.7%, 69.7%) in diarrheic patients and their cattle respectively. Multiple drug resistance was also observed among 56(43.8%) and 11(33.3%) isolates in diarrheic patients and their cattle respectively.

CONCLUSION

Our study showed high prevalence of STEC O157:H7 in diarrheic patients and their cattle. Therefore, health education should be given to the community on how to care for animals, proper sanitation, and the impact of raw food consumption.

Occurrence of Escherichia Coli O157:H7 in lactating cows and dairy farm environment and the antimicrobial susceptibility pattern at Adami Tulu Jido Kombolcha District, Ethiopia

BACKGROUND

Food-borne pathogens are the foremost causes of food-borne human illness in the world. Escherichia coli O157:H7 (E. coli O157:H7) is one of the major food-borne pathogenic bacteria around the world. Though evidence is lacking; especially in developing countries like Ethiopia, the potential health impact of E. coli O157:H7 can be high where food production, handling and consumption is often taking place under unhygienic conditions. In Ethiopia, studies reported E. coli and E. coli O157: H7 from food of animal origin, mainly meat and milk, and also animal surfaces and feces. The objective of the present study was to investigate the occurrence of E. coli O157:H7 in raw milk and the dairy production farm environment and further assess the antimicrobial resistance pattern of the bacterium.

METHODS

Samples of milk from individual lactating cows' and dairy farm environmental samples (feces, water and manure) were collected at Adami Tulu Jido Kombolcha district (ATJKD) and analyzed for the presence of E. coli O157:H7. Standard microbiological techniques including culture, biochemical testing and serological test were performed to isolate and identify the bacterium. The bacterial isolates were evaluated for antimicrobial susceptibility patterns using disk diffusion method. A questionnaire was used to collect possible factors affecting E. coli O157:H7 occurrence.

RESULTS

The overall prevalence of E. coli O157:H7 was 4.7% (19/408) (95% CI: 2.6; 6.7). Out of 19 E. coli O157:H7 isolates, 4/50, 7/154, 2/50, and 6/154 were from water, milk, manure, and feces samples, respectively. From potential risk factors considered in this study area, floor type, cleaning of pens, milking location and hand washing during the time of milking were significantly associated with the occurrence of E. coli O157:H7. The antimicrobial susceptibility pattern indicated varying degrees of resistance. All of the isolates were found to be resistant ampicillin, cephalothin, and rifampin, and 100% susceptibility was observed against the drugs: chloramphenicol, ciprofloxacin, gentamicin, nalidixic acid, kanamycin, and tetracycline. Concerning streptomycin, 63.15% of the isolates were susceptible and 36.8% showed intermediate susceptibility.

CONCLUSIONS

The occurrence of multi-drug resistance E. coli O157:H7 observed both in lactating cows and in dairy farm environments can sustain a continuous transmission of the bacteria. The occurrence of multidrug-resistant E. coli o157:H7could hamper the control and prevention efforts.

Sorbitol non-fermenting Escherichia coli and E. coli O157: prevalence and antimicrobial resistance profile of strains in slaughtered food animals in Southeast Nigeria

Antimicrobial resistance (AMR) is one of the greatest global health challenges. Reliable monitoring of AMR in bacteria in food animals is critical in order to devise mitigation strategies and empiric treatment of infections associated with the organisms. The aim of this study was to isolate sorbitol non-fermenting (SN-F) Escherichia coli from food animals (broiler chickens, cattle and pigs) slaughtered at Ikpa Market, Nsukka, Enugu State, Southeast Nigeria, detect E. coli O157 and determine the in vitro antimicrobial resistance profile of the E. coli strains. A total of 388 faecal samples were collected from randomly selected broiler chickens (n=155), cattle (n=129) and pigs (n=104). Isolation of SN-F E. coli was done using tryptic soy broth and cefixime- and potassium tellurite-supplemented sorbitol MacConkey agar (CT-SMAC). SN-F E. coli strains were confirmed biochemically and E. coli O157 detected serologically using specific E. coli O157 latex agglutination test kit. The antimicrobial resistance profile of all strains was established using the disc diffusion method. Overall, 52 (13.4 %) SN-F E. coli strains were recovered from the broiler chickens (n=31), cattle (n=12) and pigs (n=9). A significant association (χ2=9.70; P <0.05) was observed between the prevalence of SN-F E. coli and animal species. E. coli O157 was detected in two of the samples, representing 0.51% of the 388 samples processed. All the E. coli strains were resistant to at least one antimicrobial agent tested and 76% were multidrug resistant (MDR). The mean multiple antibiotic resistance indices (MARI) for isolates from chickens, cattle and pig were 0.32, 0.18 and 0.23, respectively. This study showed that a considerable percentage of food animals slaughtered in Nsukka Southeastern Nigeria are potential reservoirs of multiple-drug-resistant SN-F E. coli, including E. coli O157 that could spread to humans and the environment.

Isolation of Escherichia coli and Its Associated Risk Factor from Diarrheic Children in Wolaita Sodo Town, Southern Ethiopia

INTRODUCTION

Escherichia coli are among the major causes of mortality and morbidity in under-five children in developing nations including Ethiopia.

METHODS

A non-analytical observational study design followed by a purposive sampling technique was conducted from October 2017 to June 2018, to isolate Escherichia coli and determine its associated risk factors from diarrheic children that were admitted to Christian hospital, Wolaita Sodo town. E. coli was confirmed using standard culture and biochemical analyses of the bacterium. In addition, a semi-structured questionnaire was provided to evaluate the potential risk factors that contribute to diarrhea in children.

RESULTS

The overall isolation rate of E. coli in diarrheic children was 61.8% (68/110) (95% CI: 52.1-70.9%). Factors such as age, contact with either animals or manure, negligence to handwashing before a meal with soap, and exclusive breastfeeding at six months (p<0.05) has significant contribution to the prevalence of the E. coli in diarrheic children. The odds of being infected were highest in children whose caretakers had a habit of the negligence of handwashing before the meal (AOR = 6; 95% CI 30.8-49.8%; p = 0.01).

CONCLUSION

Improving the hygienic practices amongst parents of children reduces its Escherichia coli occurrence. Furthermore, awareness of the importance of exclusive breastfeeding to parents of children should be maximized.