We all are aware of recent outbreaks of highly drug-resistant typhoid pathogens, which were reported a few months ago. Yes, it is pretty scary, but to what extent? Let’s find more on typhoid.
Typhoid is an infectious disease, which caused 200,000 deaths at the beginning of the 21st century. The endemic regions for this disease include Asia, Southern Africa, and Latin America. The disease is caused by flagellated Gram-negative bacterium, Salmonella typhi, which may be found in food and water and spreads upon consuming contaminated edibles and drinks. The possible symptoms that could appear, include weakness, constipation, abdominal pain, and headache. Other symptoms include diarrhea, vomiting, and rashes, and to more extensive, meningitis, specific to children and immunocompromised adults.
The bacterium invades host by entering through Peyer’s patches, located in the small intestine. Peyer’s patches, like tonsils, are part of the lymphatic system that is colonized with lymphocytes and macrophages. Upon access, S. typhi invades macrophages through binding of the surface protein with specific receptors on cell surface. The engulfed bacterium then exploits macrophage to evade from host’s immune system and controls machinery of the host cell, for its own use. The bacterium secretes toxins, which are specific to S. typhi, and can neutralize immune responses against invasion. The toxin comprises of heterodimers of class A subunits, binds to pentamer of class B subunit, hence, known as A2B5. The toxin has the high affinity for sugar moieties, especially salicylate.
It also has been reported about the colonization of S. typhi in Gall Bladder. Patients with gallstones are more likely to get infected. The obstruction of the gallbladder by gallstones results in bile accumulation. Although the bile inhibits bacterium to express virulence factors, it does not prevent the pathogenic agent to grow and form a biofilm. In fact, the bile induces the production of cohesion factors on flagella and outer membrane. The presence of cholesterol in gallstones further aids S. typhi to form a biofilm. As the pathogen divides to form a strain and spread further until it reaches epithelial cells. The invasion of the pathogen to the epithelium masks the agent from bile exposure and thereby, induces virulence factors to express and cause disease. About twenty percent of individuals are carriers ( that is they are asymptomatic).
So, now we can understand, how hazardous is typhoid. In fact, if an individual is left untreated, he or she will have a high chance of acquiring cancer in the gallbladder. So, it is recommended to wash fruits and vegetables in diluted vinegar to kill out pathogens. We also should not use antibiotics until properly prescribed. Patients should seek advice from a specialist healthcare professional in order to diagnose accurately and find the potency of drugs through culture, before prescribing any other drugs.
Although hundreds of articles have been written on the same topic, the purpose of this article is to highlight the detrimental effects of typhoid. With such small action to care for hygiene, although buying concentrated antiseptic liquid may cost a little more, but suffering from such illness cost even more so.
Song, J., Gao, X., & Galán, J. E. (2013). Conferring Virulence: Structure and Function of the chimeric A(2)B(5) Typhoid Toxin. Nature.
Gonzalez-Escobedo, G., Marshall, J. M., & Gunn, J. S. (2011). Chronic and acute infection of the gallbladder by Salmonella Typhi: Understanding the carrier state. Nature Reviews Microbiology.
Muhammad Shaheen Iqba is a microbiologist and Journal manager at Life Science Journal of Pakistan, he is also pioneer and blogger at www.microbiology.pk website. He has completed his M.Phil in microbiology.
