Abstract
REVIEW Introduction Enteric bacteria are responsible for a vast proportion of diarrhoeal outbreaks worldwide, with less developed countries reporting frequent diarrhoeal outbreaks. 1 These bacteria manifest in the human gut with symptoms of bloody or watery diarrhoeal episodes and severe dehydration, and may lead to death when untreated. 2 The onset is rapid and can escalate to an outbreak, depending on the source of infection. Factors that fuel the spread of the outbreaks in less developed or impoverished communities are the lack of clean, safe water for consumption, recreational use without causing harm, contaminated water sources, and poor sanitation infrastructure. 2,3 The entry of faecal contaminants into water sources can have disastrous consequences, particularly for the poor, children under five years of age, the elderly, and immunocompromised individuals. Enteric bacteria responsible for diarrhoeal outbreaks are diarrhoeagenic Escherichia coli, Salmonella, Shigella, and Vibrio species. 4-6 The detection and identification of these bacteria and other contaminants are pivotal in the treatment processes required to reduce outbreaks. Sample collection is an essential component in the successful diagnosis of microbial pathogens. Water samples are collected in sterile glass bottles and analysed for the presence of pathogens using multiple tube fermentation or membrane filtration methods. 7,8 Human faecal samples are collected into sterile sample bottles and kept at clinics or medical rooms for varying periods before laboratory analysis. 5 The gold standard for diagnosing enteric pathogens has been conventional culture-based methods followed by confirmatory tests, such as biochemical and serological analysis. Shortfalls of these methods are the extensive isolation process and relatively late diagnosis because of the protracted time frame of microbiological analysis. 9-11 Outbreaks occurring from contamination of water sources may be source-tracked to determine the initial causative agent. Pathogen source-tracking is limited as the methods rely on culture-based techniques. 12 Culture methods for pathogen identification may be unsuitable if bacteria enter a viable but non-culturable state and cannot be resuscitated by culturing. 13,14 The integration of molecular methods for the direct detection of pathogens is increasing in diagnostic laboratories as it reduces the accurate detection time. These methods offer high specificity Background: Enteric bacteria are the inhabitants of the human gut and may cause diarrhoeal disease with high mortality rates in certain communities. The presence of enteric bacteria in faecal matter is confirmed with the gold standard of culture-based assays. Culturing methods are time-consuming, and the bacteria cannot be confirmed rapidly. Hence, molecular assays are becoming the preferred method in developed countries. Polymerase chain reaction (PCR) offers improved and rapid detection; however, post-amplification visualisation requires specialised equipment, limiting its use in underdeveloped communities. Considering the need for a simple, rapid, and portable visualisation assay for field use, a lateral flow immunoassay (LFIA) for detecting and confirming amplified genes of Salmonella, Shigella, and Vibrio species was developed.