Enteric Infections Associated with Exposure to Animals or Animal Products

Antibacterial activity and effects of Colla corii asini on Salmonella typhimurium invasion in vitro and in vivo

Background

Salmonella enterica serovar Typhimurium is a foodborne pathogen that triggers inflammatory responses in the intestines of humans and livestock. Colla corii asini is a traditional medicine used to treat gynecologic and chronic diseases in Korea and China. However, the antibacterial activity of Colla corii asini has been unknown. In this study, we investigated the antibacterial activity and effects of Colla corii asini extract on Salmonella typhimurium invasion.

Methods

To tested for antibacterial effects of Colla corii asini extracts, we confirmed the agar diffusion using Luria solid broth medium. Also, we determined the MIC (minimum inhibitory concentration) and the MBC (minimum bactericidal concentration) value of the Colla corii asini ethanol extract (CEE) by using two-fold serial dilution methods. We evaluated the expression of salmonella invasion proteins including SipA, SipB and SipC by using Western blot and qPCR at the concentration of CEE without inhibition of bacterial growth. In vitro and vivo, we determined the inhibitory effect of invasion of S. typhimurium on CEE by using gentamicin assay and S. typhimurium-infected mice.

Results

CEE significantly inhibited the growth of Salmonella typhimurium in an agar diffuse assay and had an MIC of 0.78 mg/ml and an MBC of 1.56 mg/ml. Additionally, CEE reduced Salmonella typhimurium cell invasion via the inhibition of Salmonella typhimurium invasion proteins, such as SipA, SipB and SipC. Furthermore, CEE significantly suppressed invasion in the small intestines (ilea) of mice injected with Salmonella typhimurium.

Conclusion

These findings show that Colla corii asini exerts antibacterial activity and suppresses Salmonella typhimurium invasion in vitro and in vivo. Together, these findings demonstrate that Colla corii asini is a potentially useful therapeutic herbal medicine for treating salmonella-mediated diseases.

Update on infectious enterocolitides and the diseases that they mimic

The anatomic pathologist's ability to diagnose infections, including gastrointestinal infections, in tissue sections has improved greatly in recent years. With the increasing number and availability of new molecular assays and immunostains, pathologists' understanding of the correlation between histologic patterns of inflammation and specific organisms or groups of organisms has expanded, as well as our understanding of how closely infections can mimic other frequently encountered diseases in gastrointestinal pathology (such as chronic idiopathic inflammatory bowel disease and ischemia). Anatomic pathologists continue to play a critical role in the diagnosis of gastrointestinal infections, as the examination of slides may provide a much more rapid result than microbiological cultures or other laboratory assays, and often cultures are not obtained before the patient is treated with antibiotics. Because many gastrointestinal infections are acquired through contaminated water and food, this review will focus primarily on food and water-borne infectious enterocolitides.

The actin-polymerizing activity of SipA is not essential for Salmonella enterica serovar Typhimurium-induced mucosal inflammation

Salmonella enterica serovar Typhimurium depends on type III secretion systems to inject effector proteins into host cells to promote bacterial invasion and to induce intestinal inflammation. SipA, a type III effector, is known to play important roles in both the invasion and the elicitation of intestinal inflammation. The actin-modulating activity of SipA has been shown to promote Salmonella entry into epithelial cells. To investigate whether the actin-modulating activity of SipA is required for its ability to induce an inflammatory response in vivo, we generated the SipA(K635A E637W) mutant, which is deficient in actin-modulating activity. Salmonella strains expressing the chromosomal SipA(K635A E637W) point mutation had reduced invasion abilities but still caused colitis similar to that caused by the wild-type strain in a mouse model of infection. Our data indicate that the SipA actin-polymerizing activity is not essential for the SipA-induced inflammatory response in the mouse model of infection.

Biological risks associated with consumption of reptile products

The consumption of a wide variety of species of reptiles caught from the wild has been an important source of protein for humans world-wide for millennia. Terrapins, snakes, lizards, crocodiles and iguanas are now farmed and the consumption and trade of their meat and other edible products have recently increased in some areas of the world. Biological risks associated with the consumption of products from both farmed and wild reptile meat and eggs include infections caused by bacteria (Salmonella spp., Vibrio spp.), parasites (Spirometra, Trichinella, Gnathostoma, pentastomids), as well as intoxications by biotoxins. For crocodiles, Salmonella spp. constitute a significant public health risk due to the high intestinal carrier rate which is reflected in an equally high contamination rate in their fresh and frozen meat. There is a lack of information about the presence of Salmonella spp. in meat from other edible reptilians, though captive reptiles used as pets (lizards or turtles) are frequently carriers of these bacteria in Europe. Parasitic protozoa in reptiles represent a negligible risk for public health compared to parasitic metazoans, of which trichinellosis, pentastomiasis, gnathostomiasis and sparganosis can be acquired through consumption of contaminated crocodile, monitor lizard, turtle and snake meat, respectively. Other reptiles, although found to harbour the above parasites, have not been implicated with their transmission to humans. Freezing treatment inactivates Spirometra and Trichinella in crocodile meat, while the effectiveness of freezing of other reptilian meat is unknown. Biotoxins that accumulate in the flesh of sea turtles may cause chelonitoxism, a type of food poisoning with a high mortality rate in humans. Infections by fungi, including yeasts, and viruses widely occur in reptiles but have not been linked to a human health risk through the contamination of their meat. Currently there are no indications that natural transmissible spongiform encephalopathies (TSEs) occur in reptilians. The feeding of farmed reptiles with non-processed and recycled animal products is likely to increase the occurrence of biological hazards in reptile meat. Application of GHP, GMP and HACCP procedures, respectively at farm and slaughterhouse level, is crucial for controlling the hazards.

Infective disorders of the gastrointestinal tract

Gastrointestinal infections are a major cause of morbidity and mortality worldwide. Infectious organisms are often recovered by microbiological methods, but surgical pathologists may play a very valuable role in diagnosis. This review will focus on infective disorders of the gastrointestinal tract with an emphasis on enterocolitides caused by food‐ and water‐borne pathogens. Diagnostic histological features of selected enteric infections will be emphasized, including those that mimic other inflammatory conditions of the gut (such as ischaemia or idiopathic inflammatory bowel disease), along with available diagnostic methods that can aid in diagnosis.

Pathology of food-borne infectious diseases of the gastrointestinal tract: an update

Although naturally occurring food-borne pathogens cause more than 76 million illnesses, 325,000 hospitalizations, and 5000 deaths annually in the United States, many more infections are unrecognized and unreported. In addition, mass production and distribution of food, on a global rather than a local scale, make it possible for localized instances of contamination to spread quickly to other states, provinces, and countries. Infectious organisms are often recovered by microbiological methods, but surgical pathologists may play a very valuable role in diagnosis. This review will focus on the diagnosis of food-borne infectious diseases of the gastrointestinal tract, including those that mimic other inflammatory conditions of the gut (such as ischemia or idiopathic inflammatory bowel disease); available diagnostic methods; and gastrointestinal infectious processes that pathologists should be aware of in terms of potential biologic weapons threats.

Models of antimicrobial resistance and foodborne illness: examining assumptions and practical applications

Antimicrobial resistance is an issue of increasing global concern. Several investigators have suggested that antibiotic use in food-producing animals is a major contributor to the increasing incidence of antimicrobial-resistant organisms causing illness in humans (F. J. Angulo, K. R. Johnson, R. V. Tauxe, and M. L. Cohen, Microb. Drug Res. 6:77-83, 2000; P. D. Fey, T. J. Safranek, M. E. Rupp, E. F. Dunne, R. Efrain, P. C. Iwen, P. A. Bradford, F. J. Angulo, and S. H. Hinrichs, N. Engl. J. Med. 342:1242-1249, 2000; S. A. McEwen and P. J. Fedorka-Cray, Commun. Infect. Dis. 34(Suppl. 3):S93-S106, 2002; D. L. Smith, A. D. Harris, J. A. Johnson, E. K. Silbergeld, and J. G. Morris, Jr., Proc. Natl. Acad. Sci. USA 99:6434-6439, 2002; D. G. White, S. Zhao, R. Sudler, S. Ayers, S. Friedman, S. Chen, P. F. McDermott, D. D. Wagner, and J. Meng, N. Engl. J. Med. 345:1147-1154, 2001; W. Witte, Science 279:996, 1998). In this paper, we discuss this and other assumptions relevant to a quantitative risk assessment model for salmonellosis in humans. We also discuss other important aspects of modeling food safety and food-associated antimicrobial resistance risk to humans. We suggest that the role of food-producing animals in the origin and transmission of antimicrobial resistance and "foodborne" pathogens has been overestimated and overemphasized in the scientific literature; consequently, nonfoodborne transmission, including pet-associated human cases, has been underemphasized. Much evidence exists for the potential contribution to infectious disease that may be of human or pet origin (that may contact humans through food but not be of a food origin). Risk analyses that do not acknowledge the potential for these sources of cross-contamination will understate the contribution that origin has in the realm of foodborne and food-associated diseases (e.g., Salmonella) and the resulting uncertainty levels in the food system, thus leading to biased inferences. We emphasize the importance of evaluating both the foodborne and nonfoodborne transmission risk for salmonellosis and outline the basics of an analytical modeling approach in food safety with examples to illustrate strengths and limitations in the modeling. Examples illustrate, on a simplistic level, how varying assumptions and other inputs can influence the output of food-associated quantitative risk models.

Pet-assisted therapy in the nursing home setting: potential for zoonosis

Pet-assisted therapy in the nursing home setting, as a vital component of the Eden Alternative or Human Habitat program, is gaining widespread recognition and implementation. Programs such as this help to improve the quality of life of nursing home residents by offsetting resident loneliness, helplessness, and boredom. However, use of companion animals (and, frequently, birds and fish) may be associated with the introduction of infectious entities that are normally uncommon in this setting (zoonosis). Examples include psittacosis, bartonellosis, toxocariasis, Capnocytophaga canimorsus, pasturellosis, Q fever, and leptospirosis, to name but a few. Hence vigilance for unusual clinical manifestations that may herald such diseases is necessary. In addition, prevention of such illnesses by routine veterinary screening of both resident and visiting companion animals is mandatory. Infection control policies and procedures geared toward management and prevention of zoonotic illnesses should be developed and implemented in all nursing homes offering pet-assisted therapy.

Isolation and haemolytic activity of Aeromonas species from domestic dogs and cats

Rectal swabs from 120 domestic dogs and 15 domestic cats were examined for Aeromonas species using alkaline peptone water (pH 8.6) as the enrichment medium and blood agar containing 15 mg/l ampicillin as the plating medium. Aeromonads were isolated from 13 (10.8%) dogs and from 1 (6.7%) cat. Of the 14 aeromonads isolated in the present study only 9 were available for speciation and testing in the haemolysin assay. Of these 5 were A. sobria (including one from a cat), 2 were A. hydrophila and 2 were A. caviae. Six were positive in the haemolysin assay; 4 A. sobria (one from a cat) and 2 A. hydrophila. The presence of haemolysin producing-Aeromonas species in the faeces of domestic dogs and cats may pose a public health problem for humans who come into contact with such animals.

Food borne disease summary by food commodity

Microbial pathogens may be transmitted to humans via food animals and food animal products. A quick reference table is presented to provide easy access to food safety information related to the major food animal product areas. Included in the table are the pathogens, mode of transmission, public health impact, and control and prevention strategies for poultry, beef, dairy products, and pork.

Detection of virus or virus specific nucleic acid in foodstuff or bioproducts--hazards and risk assessment

There are two possibilities for virus contamination of foodstuff and bioproducts of animal origin: i) the presence of endogenous virus as a result of an acute or subclinical infection of animal raw material used for food processing or ii) contamination of food in the course of processing or thereafter. The latter must be considered as the highest risk for human consumers since the viral contamination mostly is caused by virus shedding people and the transmitted viruses are obligate human pathogens. Food from animals consumed as raw material (e.g. oysters) is listed in a high risk category concerning viral contamination (e.g. hepatovirus). Virus contamination of bioproducts such as vaccines, blood products or biological material used in surgery and for transplantations also is more hazardous because the application of contaminating virus usually occurs by circumvention of the natural barrier systems of the body. Moreover, in many cases immunosuppressed people are treated with bioproducts. Due to an enclosing shield of high protein and lipid content in food and bioproducts viruses are well protected against physical and chemical influences, however most preparation procedures for food are destructive for viruses. The detection of pseudorabies virus and pestivirus in biological fluids was tested using polymerase chain reaction (PCR), reverse transcriptase (RT)-PCR and cell culture propagation. PCR is a powerful method to detect viral nucleic acid whereas the detection of infectious virus in cell cultures is more limited, e.g. due to protein and lipid destroying conditions. Virus contamination of bioproducts should be considered as a hazard no matter which method has been used for its detection. Examples are given about the contamination of cell lines and vaccines.

Viral infections transmitted by food of animal origin: the present situation in the European Union

The goal of this presentation was to clarify which foods are involved in viral diseases, which viruses are transmitted via food and how to evaluate the risk of a foodborne viral infection. Food items frequently identified as cause of viral disease outbreaks were shellfish harvested in sewage-contaminated water. Another common source of foodborne viral illness was cold food contaminated by infected food handlers. In the European Union the viruses most frequently associated with foodborne illness were hepatitis A virus and the SRSV's. A few isolated cases of foodborne hepatitis E were reported in Mediterranean countries. Compared to other foodborne diseases, those caused by viruses are less severe and seldom fatal. This might be a reason why the problem of viral contamination of food has been neglected. Yet, because many foodborne viral diseases are not recognized either as foodborne or as caused by viruses, the actual number of cases must be assumed to be significantly higher than the reported number. Consequently, food associated diseases of viral origin should be granted more attention.

Preventing infection from foodborne pathogens in liver transplant patients

Patients who have had an orthotopic liver transplantation (OLT) experience impaired immune function resulting from the disease process and the therapeutic use of immunosuppressive and antibacterial drugs. Immunoimpairment increases the risk of foodborne illness from bacteria, viruses, fungi, and parasites. This article describes the organisms known to cause clinically important infections and their food sources, the distinctive clinical consequences of the infection in patients who have had an OLT, and methods of preventing foodborne illness in these patients and others. Dietitians are the health care providers typically responsible for teaching OLT patients and their caregivers about safe food handling and appropriate food choices.