Can be on anything to do with microbiology (you can chose the topic) - Article Example

Cabral JP. Water microbiology. Bacterial pathogens and water. Int J Environ Res Public Health. [Internet] Oct [cited March 24];7(10):3657-703: Available from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996186/?tool=pubmed Water, despite being very essential for life, is not accessible to many people without struggle, especially in the developed and the developing countries. It is not only important to have water access, but it equally important to have safe water access because water is a common vehicle for several infectious diseases.

This is evident from the WHO estimates that mortality related to water borne infectious diseases exceeds 5 million people per year. The greatest microbial risks are because of ingestion of water contaminated with animal or human feces. Other sources of contamination are waste water discharges. Children under 5 years of age are the most affected population with these infectious diseases. Common diseases which are transmissible by water are cholera, typhoid and bacillary dysentery. Cholera is caused by gram negative rods Vibrio cholerae which are facultative anerobes.

The organisms are aquatic bacteria and their distribution depends on sodium and temperature of the water. The incubation period of the disease is 1-3 days and the disease is characterised by acute and intense diarrhoea leading to dehydration. Cholera is associated with high mortality if not treated timely. Infection due to Vibrio cholera is dependent on adhesion of the cells of the bacteria to the mucous membrane of the intestine and production of cholera toxin. Cholera is very famous for its pandemics.

The genes responsible for toxin production are harbored in the CTX? segment (7–9.7 kb) of the chromosome. The strains of the organism are common in the environment, especially is estuaries. Non-culturable but viable bacteria are responsible for episodic nature and the sudden appearance of violent cholera outbreaks, followed by a rapid slowing down. The next infection that is worth mentioning in water related infectious disease is salmonellosis which are actually a group of diseases caused by enterobactericea family and genus salmonella.

There are mainly 2 types of diseases, typhoid fever and paratyphoid fever, and gastroenteritis. Clinical symptoms are caused even with low infective doses. Symptoms occur within 12 hours of ingestion of contaminated food or water. Poor hygiene and sanitation are main contributing factors to the disease. The principal habitat of the organisms is intestinal tract of the humans and animals. Humans infected with salmonellae can carry the bacteria in the gut without signs of disease and can continue to be reservoirs of the disease.

The bacteria survive sewage treatments if suitable germicides are not used in sewage processing. The third important water borne infectious disease is shigellosis or bacillary dysentery caused due to Gram-negative bacteriae of the enterobacteriacea family. The incubation period of the disease is 1-4 days and the disease manifests as fever, anorexia, fatigue and malaise along with bloody stools. The initial step in pathogenesis of bacillary dysentery is penetration of the colonic mucosa. The main virulence factor of the disease is the shigella toxin.

Even shigella has caused several epidemics and continues to be an epidemic in some parts. Other bacteria which cause water borne infectious diseases are Escherichia coli, Mycobacterium Avium Complex, Helicobacter Pylori and Aeromonas Hydrophyla. Regular microbial analysis of water does not detect these pathogens. Thus, safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere.