Sohail Naushad

By Sohail Naushad, Dele Ogunremi and Hongsheng Huang

Salmonella causes significant illness in humans and animals and is a major public health concern worldwide, contributing to an increased economic burden. Salmonella is usually transmitted through the consumption of contaminated food, such as raw or undercooked meat, poultry, eggs, and dairy products, and water or through contact with infected animals or their environment. The most common symptoms of salmonellosis, the illness caused by Salmonella, include diarrhea, fever, and abdominal cramps; in severe cases, the infection can lead to hospitalization and even death. The classification and taxonomy of Salmonella were historically controversial, but the genus is now widely accepted as composed of two species and over 2600 serovars. Some of these serovars infect a single host, that is, host-restricted, whereas others have a broad host range. Colonization of the host is complex and involves a series of interactions between the Salmonella and the host’s immune system. Salmonella utilizes an array of over 300 virulence factors, mostly present in Salmonella pathogenicity islands (SPIs) to achieve adherence, invasion, immune evasion, and, occasionally, systemic infection. Once colonized, it secretes a number of toxins and inflammatory mediators that cause diarrhea and other symptoms of salmonellosis. The overuse and misuse of antibiotics in human and animal medicine and agriculture have contributed to the development of antimicrobial resistance (AMR) in Salmonella, making AMR strains more severe and difficult to treat and increasing the risk of morbidity and mortality. Various methods are used for the detection of Salmonella, including traditional culture methods, molecular methods such as polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP), and immunological-based assays. Because of its ubiquitous distribution, the prevention and control of Salmonella transmission remain a significant challenge. This chapter briefly covers the history, classification, transmission, pathogenesis and virulence factors, antimicrobial resistance genes, detection, diagnosis, surveillance, prevention, and control pertaining to Salmonella.

Part of the book: Salmonella