## 1 Introduction  
Naturally, animals harbour significant food- water-borne pathogens in their gastrointestinal tract which they shed in feces, and thus the animals serve as reservoirs and as potential sources of contamination [1]. Contamination of the environment, crops and humans may occur via unplanned release of these wastes by runoffs from wastes and housing facilities or from manure applied as fertilizer on farms or leachate infiltrating through soils and polluting underground springs and wells. Consequently, human health is exposed to threats of numerous gastrointestinal tract infectionsassociated with these zoonotic pathogens [2]. Some of the bacterial pathogens so far identified and characterized from animal manure included _E. coli_, _Salmonella_ and _Campylobacter_ species which are of relevance to public health at local, national and global dimensions [3]. Furthermore, [PERSON] et al. [4] reported that the type and concentration of pathogenic microbes present in animal manure varies from farm to farm and is dependent on the species and age of the animal, the ration of diet and the physicochemical composition of the manure. Also, the geographical location, local conditions, population size and seasonal variation may influence the level of these microbes reported in manure [5]. Exposure of human, farm produce and animals to _E. coli_, _Salmonella_, _Shigella_ and _Campylobacter_ species is a plausible route of transmission and subsequent infection; therefore, they are regarded as important causes of enteric infections globally [6; 7]. Enteric infections are prime issues in the public health sectors across the globe as they are associated with significant economic impacts [8]. It is therefore of relevance to monitor the occurrence of these microbes on farms and implement strategies to reduce, control or eliminate them before employing manure as a fertilizer for soil amendment [9]. Anaerobic digestion of animal manure in an airtight chamber (bio-digester) has been viewed as a plausible method for the control of bacterial pathogens resulting in the reduction of the microbes to threshold levels that depict human safety [10]. However, the rate of decimation of the microorganisms depends on the temperature of the process, the particular bacterium, the retention time and the metabolites generated during the process [11; 12]. Antimicrobials are quite essential in the chemotherapy of infections caused by bacteria, combating the illness by shortening of its lifespan, reducing its symptoms and chances of transmission in the community [13; 14]. However, there has been growing increase in the resistance of some microorganisms to the potentially available antibiotics. More especially, some antibiotics that are vital for treatment of bacterial infections of humans are currently used in farm practices for therapeutic and growth-promotion purposes [15; 16]. Consequently, antibiotic-resistant bacteria may emerge which may negatively influence or compromise the outcome of treatment regimens issued to patients resulting in increased morbidity, mortality and economic burdens [17; 18]. More elaborately, antibiotic-resistant bacteria are widespread and their numbers are growing; this represents a significant global health problem attributed to the use and misuse of antibiotics [19]. As a consequence, in the last decade, environmental bacteria have been regarded as reservoirs of antibiotic resistance determinants and prospective agents of novel resistance genes that could actually contribute to resistance in clinical settings via transfer of these genes to clinical pathogens. Accordingly, knowledge on the origin of these antibiotic resistance genes, their distribution in the environment and factors that favour their spread is crucial in a bid to establish strategies to circumvent antibiotic resistance [19].