Identification of Immunogenic Salmonella Enterica, Research Paper Example

Introduction

Many individuals serve as host carriers for a number of infectious diseases and possess the potential to spread these diseases throughout the community. It is important to identify these challenges and to determine how carriers of different bacteria play a role in bringing disease to communities, particularly when there is a risk due to poor environment conditions, low immunity, and limited healthcare alternatives available. Tropical diseases are particular challenging because communities that are affected by these diseases typically have low resistance and face critical challenges in fighting disease. Therefore, it is important to identify the resources that are available to address tropical diseases, those affected by the disease, and the carrier population as a whole. These concerns are relevant because the relationship between host and pathogen is not well understood. It is important to consider some of the research that has evolved regarding this framework and the scientific approaches that have been taken to identify this relationship. The following discussion will address the conditions surrounding Salmonella enterica and its impact on carriers and the host environment, emphasizing the use of different techniques in the development of a serious tropical disease known as Typhoid Fever. The discussion will address the serovars S. Typhi and S. Paratyphi A more closely in order to improve the identification of its impact and relationship to human carriers, hosts, and the subsequent risk of infection. This examination will identify potential advancements in the development of new strategies to detect these serovars in order to promote greater prevention and awareness of the causes of Typhoid Fever.

Analysis

An article by Charles et.al provides background information regarding S. Typhi and how it causes Typhoid Fever in humans, as it is derived from Salmonella enterica, which enters the body through contaminated food or water (2). This bacteria enters into the gastrointestinal mucosa and eventually replicates in the bloodstream to cause infection (Charles et.al 2). For many patients, infection is treated early and is cleared out of the bloodstream; however, there is a potential for chronic infection in some individuals, which may not demonstrate symptoms and could occur for many years (Charles et.al 2). Perhaps most important is that a group of chronic carriers may spread the infection to others through fecal bacteria, thereby posing a risk to new communities (Charles et.al 2). It is necessary to identify these chronic carriers and attempt to isolate them to maintain greater control within communities, but it is difficult to identify this group of carriers and the level of pathogenic exposure for other persons within a given community (Charles et.al 2). There are considerable challenges in establishing detection mechanisms that will be effective in identifying carriers as early as possible, particularly since bacterial shedding is not consistent and frequent (Charles et.al 2). The Vi antigen and the subsequent antibody response is a possible alternative to identify carriers; however, this method is not well known at this time (Charles et.al 2).

Understanding the role of carriers is a critical factor in the development of new strategies to support and prevent disease (Charles et.al 2). Therefore, it is necessary to evaluate a method known as in vivo-induced antigen technology (IVIAT), which is described as the following: “IVIAT identifies humorally immunogenic bacterial antigens expressed in vivo and not in bacteria grown in standard laboratory conditions. We hypothesized that S. Typhi surviving in the biliary tract of humans may express a proteomic profile distinct from that expressed in bacteria grown using standard in vitro conditions or during acute infection” (Charles et.al 2). Under these conditions, it is possible that the identification of carriers could be improved so that there is a potential opportunity to prevent carrier spread of the bacteria to others (Charles et.al 2). The research study identified patients through cholecystectomy, whereby blood and bile samples were taken in order to determine if there was a positive result for S. Typhi (Charles et.al 3). In addition, other volunteers were identified from areas where typhoid fever was a frequent occurrence (Charles et.al 3).

After all appropriate testing was conducting using the study population, it was determined that several genetic matches demonstrated that S. Typhi carriers experienced an increased level of immunoreactivity in some cases; furthermore, the IVIAT protocol led to the identification of 56 S. Typhi proteins, which serve as biomarkers for carriers and represent a means of examining the survival of the bacteria within these carriers (Charles et.al 6). It was also determined that YncE is highly immunoreactive and may represent infection in either an acute or chronic state (Charles et.al 6). Nonetheless, additional studies are required in order to identify the potential benefits of this method in identifying carriers in larger populations on a more consistent basis (Charles et.al 6). It is expected that additional studies may shed some light regarding the impact of IVIAT in expanded trials to establish greater genetic differentiation and antigen-specific responses (Charles et.al 6).

In recent years, there has been an increased interest and focus on vaccinations in order to protect human beings from the risk of different forms of Salmonella. However, Typhoid Fever remains a significant problem in many nations, particularly in Southeast Asia (Crump and Mintz 241). It is evident that screening for the disease continues to be a challenge because blood culture is not always the most effective method of identification (Crump and Mintz 241). Therefore, additional methods must be explored that may have a positive impact on patient outcomes and on the growth of disease prevention strategies (Crump and Mintz 241). With the vaccination approach, two viable options are currently available, including the Ty21a vaccine and the parenteral Vi vaccine, both of which are available for children (Crump and Mintz 242). Furthermore, a third vaccine known as Vi-rEPA has been tested in Vietnamese children with a high efficacy rate of 91.5 percent, with additional vaccines currently under research (Crump and Mintz 242). The use of vaccinations in the affected countries continues to be low, as the resources and financing is not available to support widespread vaccination to prevent the disease (Crump and Mintz 242). In addition, there is some degree of resistance to these vaccines, which represents a challenge in maintaining control of the spread of bacteria and subsequent infection (Crump and Mintz 242).

Salmonella enterica also serves as a possible vaccine carrier for live vaccination methods, using the bacteria to prevent infection (Hegazy and Hensel 111). Furthermore, “the use of live attenuated Salmonellae to deliver recombinant antigens to the immune system is an attractive strategy for the construction of multivalent vac­cines” (Hegazy and Hensel 115). Under these conditions, it is possible that Salmonella possesses the ability to function by providing plasmid-encoded antigens in order to fight any number of diseases, including cancer (Hegazy and Hensel 115). In considering these recombinant bacteria as possible methods of vaccination, it is important to recognize that in some cases, there are significant problems associated with resistance to the bacteria and the vaccination itself, which could pose significant problems in providing the vaccine’s value to patients (Hegazy and Hensel 115). These factors are relevant because the identification of the bacteria and its function in humans continues to be difficult to manage (Hegazy and Henzel 115).

Perhaps most important is the identification of specific molecular structures that will enhance the ability to manage and prevent the spread of infection (Hegazy and Henzel 122). This is likely to be accomplished through the continued growth and development of therapeutic uses for Salmonella in order to accomplish the desired objectives in diagnosis and treatment (Hegazy and Henzel 122). These factors are critical because they support the continued identification of uses for Salmonella enterica and other derivatives so that human control over Typhoid Fever and other conditions may be accomplished over time, including an increased understanding of vaccinations using this bacteria (Hegazy and Henzel 122).

Conclusion

The prevalence of Salmonella enterica in the human gut is a serious concern because it may contribute to the spread of Typhoid Fever, particularly in areas where there is limited control over the disease. It is important to recognize the role of carriers in this process, and the ability to identify these carriers plays a valuable role in preventing the spread of infection to others. In communities where tropical conditions exist, this is a serious problem that requires increased attention in order to determine if new methods of vaccination and other strategies are available to support the growth of research in this area, including genetic factors. It is anticipated that research in this area will provide a greater understanding not only of the role of carriers of Salmonella enterica, but its human path and its function in both carriers and those who are infected. These factors must continue to be addressed as a means of exploring new insight into this form of bacteria and its overall impact on human beings with low immunity, or those who face other barriers.

Works Cited

Charles, Richelle C., Sultana, Tania, Alam, Mohammad Murshid, Yu, Yanan, Wu-Freeman, Ying, Bufano, Meagan Kelly, Rollins, Sean M., Tsai, Lillian, Harris, Jason B., LaRocque, Regina C., Leung, Daniel T., Brooks, W. Abdullah, Nga, Tran Vu Theiu, Dongol, Sabina, Basnyat, Buddha, Calderwood, Stephen B., Farrar, Jeremy, Khanam, Farhana, Gunn, John S., Qadri, Firdausi, Baker, Stephen, and Ryan, Edward T. “Identification of Immunogenic Salmonella enterica Serotype Typhi Antigens Expressed in Chronic Biliary Carriers of S. Typhi in Kathmandu, Nepal.” PLOS Neglected Tropical Diseases, 7.8(2013): 1-8.

Crump, John A., and Eric D. Mintz. “Global trends in Typhoid and Paratyphoid Fever.” Clinical Infectious Diseases 50.2(2010): 241-246.

Hegazy, Wael Abdel Halim, and Michael Hensel. “Salmonella enterica as a vaccine carrier.” Future Microbiology, 7.1(2012): 111-127.