Systemic listeriosis in caged canaries (Serinus canarius)

Listeria Occurrence in Conventional and Alternative Egg Production Systems

Listeria continues to be a persistent foodborne pathogen that is responsible for human cases of listeriosis when contaminated food products are consumed. Human subjects considered to be most susceptible include the elderly, immunocompromised, and pregnant women. Listeria is characterized as a saprophytic organism with the capability of responding and adapting to constantly changing environments because it possesses multiple stress response mechanisms to overcome varying temperatures, salt concentrations, and pH, among others. Primary foods and food products associated with listeriosis include dairy products and ready-to-eat meats such as turkey products. Historically, chicken eggs have not been identified as a primary source of Listeria, but the potential for contamination during egg production and processing does exist. Listeria species have been isolated from egg-processing plant equipment and are presumed to occur in egg-processing plant environments. Whether Listeria is consistently disseminated onto eggs beyond the egg-processing plant is a risk factor that remains to be determined. However, research has been conducted over the years to develop egg wash solutions that generate combinations of pH and other properties that would be considered inhibitory to Listeria. Even less is known regarding the association of Listeria with alternative egg production systems, but Listeria has been isolated from pasture flock broilers, so it is conceivable, given the nature of the outdoor environments, that layer birds under these conditions would also be exposed to Listeria and their eggs become contaminated. This review focuses on the possibility of Listeria occurring in conventional and alternative egg-laying production and processing systems.

Prevalence, virulence genes, and antimicrobial resistance profile of Listeria monocytogenes isolated from retail poultry shops in Beni-Suef city, Egypt

OBJECTIVE

This study investigated the prevalence of Listeria monocytogenes in retail poultry shops, characterized the antibiotic resistance profile, and detected the genotypic pattern of virulence genes.

MATERIALS AND METHODS

Broiler meat (n = 90), intestinal content (n = 40), and environmental samples (n = 95) were collected for this study. Besides, hand swabs (n = 20) were obtained from the poultry shop workers and stool samples (n = 40) were collected from the outpatient clinics of Beni-Suef University Hospital, Egypt. The samples were subjected to isolation and identification of L. monocytogenes by conventional bacteriological examinations and biochemical tests, followed by confirmatory identification by the polymerase chain reaction.

RESULTS

Among the collected samples (n = 285), L. monocytogenes could be detected in 14.4% (n = 41/285) of the samples, where 30.0% (n = 12/40) of the intestinal content was positive. Similarly, 10.0% (n = 9/90), 15.0% (n = 3/20), and 12.5% (n = 5/40) of the samples of meat, hand swabs, and stools were found positive for L. monocytogenes, respectively. A total of 12 (12.6%) out of 95 environmental samples were positive for L. monocytogenes. Based on the antimicrobial sensitivity profile, most of the recovered isolates were multidrug-resistant against most commonly used antibiotics.

CONCLUSION

The findings conclude that poultry shops play a vital role in transmitting L. monocytogenes to the consumers. Asymptomatic poultry shop workers should draw attention to their potentials for spreading the infection to the consumers through the contaminated carcasses. Low hygienic standards are present in commercial poultry shops that increase the risk of contamination in the sold products.

Listeriosis in animals, its public health significance (food-borne zoonosis) and advances in diagnosis and control: a comprehensive review

Listeriosis is an infectious and fatal disease of animals, birds, fish, crustaceans and humans. It is an important food-borne zoonosis caused by Listeria monocytogenes, an intracellular pathogen with unique potential to spread from cell to cell, thereby crossing blood-brain, intestinal and placental barriers. The organism possesses a pile of virulence factors that help to infect the host and evade from host immune machinery. Though disease occurrence is sporadic throughout the world, it can result in severe damage during an outbreak. Listeriosis is characterized by septicaemia, encephalitis, meningitis, meningoencephalitis, abortion, stillbirth, perinatal infections and gastroenteritis with the incubation period varying with the form of infection. L. monocytogenes has been isolated worldwide from humans, animals, poultry, environmental sources like soil, river, decaying plants, and food sources like milk, meat and their products, seafood and vegetables. Since appropriate vaccines are not available and infection is mainly transmitted through foods in humans and animals, hygienic practices can prevent its spread. The present review describes etiology, epidemiology, transmission, clinical signs, post-mortem lesions, pathogenesis, public health significance, and advances in diagnosis, vaccines and treatment of this disease. Special attention has been given to novel as well as prospective emerging therapies that include bacteriophage and cytokine therapy, avian egg yolk antibodies and herbal therapy. Various vaccines, including advances in recombinant and DNA vaccines and their modes of eliciting immune response, are also discussed. Due focus has also been given regarding appropriate prevention and control strategies to be adapted for better management of this zoonotic disease.

Listeria monocytogenes infection in poultry and its public health importance with special reference to food borne zoonoses

Listeriosis is a disease that causes septicemia or encephalitis in humans, animals and birds. Although, the disease is rare and sporadic in poultry but if occurs then causes septicemia or sometimes localized encephalitis. Occasionally, the disease is seen in young chicks and the causative agent, like in humans and animals, is Listeria monocytogenes. The organism is capable to infect almost all animals and poultry; however, outbreaks of listeriosis are infrequent in birds. It is widely distributed among avian species and chickens, turkeys, waterfowl (geese, ducks), game birds, pigeons, parrots, wood grouse, snowy owl, eagle, canaries, which appear to be the most commonly affected. Chickens are thought to be the carriers of Listeria and also the prime reservoirs for the infection and thus contaminate the litter and environment of the poultry production units. Listeriosis is often noticed along with other poultry diseases such as coccidiosis, infectious coryza, salmonellosis, campylobacteriosis and parasitic infections, signifying the opportunistic nature of the organism. Intestinal colonization of poultry and the presence of L. monocytogenes in feces represent a potential source of the organism for listeriosis in ruminants. Man gets infection from raw broiler meat due to Listeria contamination and unhygienic conditions of the processing area, rather than acquiring direct infection from birds. With the changing food habits of the people, the health consciousness is also increasing and since listeriosis has now been recognized as an emerging food borne zoonoses. Therefore, this review has been compiled to make aware the poultry producers and the consumers of poultry meat/products regarding the importance of the disease and its public health significance.