Prevalence and antibioresistance of Escherichia coli and Salmonella isolated from lettuce and irrigation water in Ouagadougou, Burkina Faso

Abstract

Introduction. The use of partially or untreated wastewater in the irrigation of vegetable crops constitutes a risk of microbiological contamination that can cause diarrhea in the consumer. Aim. This study mainly aimed to assess the level of contamination of irrigation water and lettuce as well as to determine the antibiotic resistance profile of isolated bacteria. Methods. A total of eighty samples of lettuce and ten irrigation waters were collected from the market gardening sites of Boulmiougou, Bissigin, the National School of Public Health and Tanghin. The research of thermotolerant coliforms, Escherichia coli and Salmonella was done following ISO standard methods. Isolated Escherichia coli and Salmonella strains were tested for their resistance profile by using the Kirby-Bauer method with a panel of twenty different antibiotics. Results. Out of the eighty lettuce samples, 68.75% (55) contained thermotolerant coliforms with an average load of 8.75 ×105 CFU g-1. The prevalence of Escherichia coli was 57.5% (46) and Salmonella prevalence was 11.25% (9) including eight strains of Salmonella enterica spp. and one strain of Salmonella enterica arizonea. All irrigation waters were contaminated by thermotolerant coliforms at an average concentration of 3.11×104 CFU/100mL. The prevalence of Escherichia coli in the irrigation waters was 40% (4/10) while Salmonella enterica spp. was 20% (2/10). The highest antibiotic resistance was found in Escherichia coli strains with ampicillin 28.26%, amoxicillin + clavulanic acid 26.09% and tetracycline 19.57%. Conclusion. The water used to irrigate vegetable crops in Ouagadougou could be a major source of contamination of vegetables by microorganisms. In addition, the consumption of lettuce would constitute a risk of propagation of salmonellosis among the population.

Characteristics of Nontyphoid Salmonella Isolated from Human, Environmental, Animal, and Food Samples in Burkina Faso: A Systematic Review and Meta-Analysis

“…Increasing evidence indicates that irrigation water is a source (or a vehicle) for the transmission of Salmonella [73][74][75][76]. This result is worrying, given that in Ouagadougou, all kinds of wastewater (urban or industrial wastewater) are used in an unplanned and uncontrolled way in urban and peri-urban agricultural activities, including the irrigation of vegetables consumed raw (lettuce in particular) [32]. Moreover, the lack of mineral matter in the soil and the impossibility for some producers to obtain chemical fertilizers have led them to use animal manure as fertilizer, which is more economical and beneficial for the environment.…”

Determinación de Escherichia coli/coliformes en lechugas expendidas en el mercado 10 de Agosto de la ciudad de Cuenca

“…Esta ausencia de E. coli sugiere que las prácticas de manejo y los protocolos de higiene en uso son adecuados. Sin embargo, en una investigación realizada por Rouamba et al en Burkina Faso, se determinó que el 57,5% de las muestras de lechuga contenían E. coli(16). De manera similar, Magdaniel y Fragoso-Castilla en Colombia reportaron que el 100% de las lechugas en un mercado al aire libre mostraron crecimiento positivo de E. coli(17).La identificación de E. coli en comestibles, en particular en hortalizas frescas como la lechuga, representa un asunto significativo debido a su capacidad para provocar afecciones gastrointestinales en quienes los consumen(18).…”