Molecular epidemiology of antibiotic-resistant enterococcus spp. from farm to food-production chain in intensive poultry production in KwaZulu-Natal, South Africa.

Masters Degree. University of KwaZulu-Natal, Durban.Extensive antibiotic use in intensively-farmed poultry exerts selection pressure for the emergence of multidrug-resistant pathogens. The aim of this study was to determine the antibiotic resistance and virulence profiles of Enterococcus spp. along the farm to food-production chain continuum in an intensive poultry system in the uMgungundlovu District in Kwazulu-Natal, South Africa. A total of 187 samples along the poultry farm to food-production chain continuum (litter, faeces, transport, holding, abattoir and retail meat) were evaluated for the presence of Enterococcus spp. Molecular confirmation by PCR, targetting the genus- (tuf) and species-specific (sodA) genes was undertaken. Susceptibility profiles were assessed by Kirby-Bauer disk diffusion against the WHO-AGISAR recommended panel of antibiotics for Enterococcus spp. using CLSI guidelines. Antibiotic resistance and virulence genes were detected using real-time PCR. Genetic relatedness between isolates across the continuum was evaluated by REP-PCR. Of 134 isolates identified across the continuum, with a prevalence of 72%, molecular speciation confirmed the isolates as E. faecalis (36%), E. faecium (31%), E. gallinarum (2%) and other Enterococcus spp. (31%). Resistance to tetracycline (80%), erythromycin (71%), nitrofurantoin (17%), ampicillin (15%), streptomycin (15%), chloramphenicol (11%), ciprofloxacin (5%), tigecycline (4%), gentamicin (4%), teicoplanin (3%) was observed among Enterococcus spp. but no vancomycin resistance (0%). E. faecium displayed 24% resistance, and 21% were of intermediate susceptibility to quinupristin-dalfopristin. Twenty-one percent (21%) of E. faecalis and 100% of E. gallinarum, also showed intermediate susceptibility to vancomycin. Forty-three percent (43%) of E. faecium were multidrug-resistant (MDR) (resistant to 1 or more antibiotics in 3 or more antibiotic classes). The most frequently observed antibiotic resistance genes, associated with the phenotypic profiles, were tetM (76%) and ermB (67%) with a smaller percentage noted for aph(3’)-IIIa (12%) and vanC1 (1%). Virulence genes efaAFs (100%), cpd (96%) and gelE (81%) were more frequently detected in E. faecalis. The cell wall adhesin (efaAFm) was more common in E. faecium (100%) and other Enterococcus spp. (71%). Clonality evaluated by REP-PCR revealed that isolates along the continuum are highly diverse with major REP-types often consisting of isolates from the same sampling point in the continuum

Antibiotics threats on vegetables and the perils of low income nations practices

Loose control on antibiotics usage, improper waste disposal, the use of reclaimed water in crop production, and other poor practices can enhance the antibiotic contamination of soil, water and the environment. These then threaten food safety and human health. Highly susceptible crops such as vegetables easily accumulate antibiotics and can be a viable route for the spread of antibiotics resistant bacteria and the induction of antibiotics resistant genes. This paper discusses common usages and negative impacts of antibiotics, and the extent of their contamination in various environmental components viz-a-viz their impact on vegetables. Peculiar challenges and practices related to low income nations (LINs) as well as their consequential effects are also discussed. Areas of future research that needs attention in LINs are succinctly presented. This review therefore will serve as tool to increase the awareness of consumers, food producers, environmentalists and policy makers on the impact of antibiotics and inadequate practices on vegetable production