The Effect of Escherichia Coli on Human - Coursework Example

An Investigation of E. coli Infection Introduction E. coli, also known as Escherichia coli is type of harmless bacteria that lives in intestines. There are some that cause diarrhoea, sickness, kidney failure and death in extreme cases. Children and adults with weak immune systems are vulnerable to such diseases. E. coli infections can be caused by eating or drinking contaminated foods. Generally E. coli infections can heal in 5 to 10 days without treatment (US National Library of Medicine, 2008). E. coli Infection E. coli are bacteria that are mostly harmless, but there are strains that can cause sickness, diarrhoea, urinary tract infections, pneumonia, and respiratory illness. Some types of E. coli are used as markers for water contamination. A type of E. coli produces a Shiga toxin, and causes disease. These types of bacteria are known as Shiga toxin producing E. coli (STEC), or verocytotoxic E. coli (VTEC), or enterohemorrhagic E. coli (EHEC). E. coli O157:H7 is the most common STEC, responsible for several outbreaks. E. coli O157 was identified as a pathogen in 1982. Infection can be caused in people of any age. However, young children and elderly are more likely to develop haemolytic uremic syndrome and severe illness. Symptoms of STEC include severe stomach cramps, diarrhoea, and vomiting. In some cases symptoms are accompanied by fever less than 38.5 C. People infected by STEC, generally recover within 5 to 7 days, but in certain cases infections could develop into severe or life threatening disease. Approximately 5-10 percent infected with STEC develop haemolytic uremic syndrome. Symptoms for haemolytic uremic syndrome include decreased urination, tiredness, and paleness in cheeks and inside lower eyelids. The kidneys may stop working and other serious complications may develop. Generally recovery occurs within weeks, but a few cases result in death or permanent damage. There is an incubation period of 3 to 4 days after ingestion of STEC. In case of occurrence of haemolytic uremic syndrome, it is generally after 7 days after first symptoms. Initial symptoms are often mild stomach pain or diarrhoea that worsens over time. STEC is commonly found in guts of goats, sheep, cattle, deer, and elk. Also, pigs and birds could spread STEC. Exposure to ETEC is generally by ingestion, such as consumption of food contaminated with STEC, consumption of raw milk, consumption of infected water, contact with animals, or contact with faeces. Foods, such as raw milk, unpasteurized apple cider, and cheese made from raw milk have been considered to be at high risk of contamination. Other forms of exposure include swimming, touching animals, and/or lack of proper hygiene (National Center for Zoonotic, Vector-Borne, and Enteric Diseases, 2008). National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) has attributed haemolytic uremic syndrome to cause acute kidney failure in children by destroying red blood cells, such as platelets. Most children suffering from haemolytic uremic syndrome recover without permanent damage, though it can be life threatening. Haemolytic uremic syndrome is caused by toxins made by E. coli entering the bloodstream and destroying red blood cells. Symptoms of haemolytic uremic syndrome include the child being pale, irritable and tired. Also, bruises or bleeding from nose or mouth can occur. Symptoms of haemolytic uremic syndrome may become apparent after a week of incidence of digestive problems. 50 percent of children developing haemolytic uremic syndrome result in acute kidney failure. This causes urine output to decrease and appear reddish. Damaged red blood cells clog the blood vessels in the kidneys, causing additional workload for the blood vessels in removing wastes and extra fluid from the blood and slowing urine formation. When the excess fluids and wastes are not removed from the body, high blood pressure, swelling of face, feet, hands or body may occur. NKUDIC has suggested that a doctor must be consulted if the symptoms describe above become apparent or there is no urination for more than 12 hours. A microscopic examination of blood sample can determine whether the blood cells have misshaped, confirming haemolytic uremic syndrome. Treatments for haemolytic uremic syndrome are aimed at providing immediate relief and preventing further complications by maintaining normal salt and water levels within the body. Some cases may require transfusion of red blood cells by intravenous, IV, or tube. Severe cases may require dialysis to provide temporary relief to the kidney. Significant kidney damage may slowly develop into permanent kidney failure requiring long-term dialysis or kidney transplant. NKUDIC has suggested that limiting protein in the diet and treating high blood pressure with drugs, such as angiotensin-converting enzyme inhibitors delays the process of permanent kidney failure. Haemolytic uremic syndrome can be prevented by washing foods, properly cooking foods, and avoiding swimming areas that are unclean. A syndrome similar to haemolytic uremic syndrome is thorombotic purpura, where clotting of blood within small blood vessels, anemia by fragmentation of red blood cells, and shortage of platelets may cause bruising, neurologic problems, impaired kidney function, and/or fever (Medicinenet, 2009). Water Contamination Water is contaminated with E. coli by human and animal wastes during rainfalls, snow melts and precipitation, washing E. coli into streams, creeks, rivers, lakes and/or ground water. Inadequate treatment of these forms of water may cause exposure to E. coli. STEC and E. coli O157 can be detected by laboratory testing of stool specimens on sorbitol-MacConkey (SMAC) agar. Water can be treated by using chlorine, ultra violet light, or ozone to inactivate E. coli (US Environmental Protection Agency, 2006). Case Analysis An investigation would be conducted to identify symptoms and infections among the individuals. According to the clinical vignettes, E. coli O157 has been isolated in two patients within the elderly ward. A member of the staff has reported absence of gastro-intestinal symptoms. A child has been recently admitted with bloody diarrhoea. The child is being treated for haemolytic uremic syndrome. Stool test for E. coli O157 has tested negative. To investigate the case, sampling would have to be conducted to determine the presence of E. coli O157. This includes sampling water, food, and waste. Random samples of food, especially meat products and waste would be collected and sealed to preserve the integrity of the sample. These samples would be appropriately labelled, preserved and shipped to the laboratory for analysis. Water samples would be collected and sent to the laboratory for analysis. US Environment Protection Agency has given extensive details for the collection of environmental samples, recommended equipment and procedures to avoid contamination of the samples. Samples would be collected according to the procedures, labelled, packed and shipped to the laboratory. Appropriate sample collection forms would be filled and chain of custody maintained. Separating an organism from a sample having high levels of background debris has been a challenge in the analysis of environmental samples. Immunomagnetic separation technique has been developed to overcome this problem (Yakub, 2004). Improved isolation of E. coli O157 could be achieved for Immunomagnetic separation technique by the use of large enrichment volumes (Ogden, 2000). E. coli O157 has been isolated in two individuals establishing the presence of E. coli O157 in the environment. To determine the extent of infection, stool and blood samples would be collected from the individuals for microbiological analysis to detect the presence of STEC and E. coli O157. In certain cases, especially in children, certain strains of E. coli can get into blood from the intestines causing serious illness (Dowshen, 2007). E. coli O157 are tested in stool samples by growing the bacteria in culture and testing for Shiga toxin. Blood levels of electrolytes, blood urea nitrogen, creatinine, and complete blood counts are performed (MedicineNet, 2009). Food, waste and water samples would help determine possible source of E. coli infection. If absent, it will confirm that infection occurred externally and precautionary measures need to me taken to prevent further contamination. Stool tests would confirm E. coli infection within individuals. Blood test would help confirm progression of E. coli infection to haemolytic uremic syndrome. In the absence of gastro-intestinal symptoms, if the stool tests confirm to be negative, and blood tests also confirm to be negative for E. coli O157, it is likely that the infection has subsided in the individuals. However, individuals would be advised rest and symptoms continued to be monitored. In case of the patient with diarrhoea, caution would be exercised to ensure that antibiotics are not administered. Antibiotics are not helpful in the treatment of diarrhoea, and some studies suggest that use of antibiotics may increase the risk of developing haemolytic uremic syndrome. Treatment should focus on the prevention of dehydration by the replacement of fluids and electrolytes. Patients treated for haemolytic uremic syndrome need supportive care, and if there is kidney failure, dialysis may be required (MedicineNet, 2009). Prevention of E. coli Infection STEC infections can be prevented by practicing proper hygiene, such as washing hands after using bathroom, changing diapers and before eating food, cooking meats properly above 70C, avoiding consumption of raw milk, avoid swallowing water while playing or swimming, and preventing cross contamination. World Health Organization has recommended two principles for the prevention of nosocomial infection; separate infection source from the rest of the facility, and cut off transmission routes. Standard precautions include hand washing, use of gloves, use of mask, eye protection and face shield, wearing gown, proper use of patient-care equipment, environmental control, and use of linen, following adequate procedures while handling occupational health and bloodborne pathogens, and placement of patient care. Other precautions include cleaning, sterilizing, disinfection and hand hygiene. Cleaning removes microorganisms, such as bacteria from the surface. Cleaning by a standard procedure or the use of automation will provide a certain level of cleanliness. Sterilization is conducted to free an object from microorganisms. Physical methods, such as autoclaving, dry thermal or wet thermal sterilization, irradiation, or mechanical separation by filtration are often used for sterilization. Chemical methods include use of ethylene oxide or other gases, or immersion in solutions with sterilization properties, such as glutaraldehyde. Disinfection, such as high, intermediate or low-level should be selected depending on the risk and toxicity of the microorganism. Also, the disinfectant must not adversely affect humans or the environment. In a health care setting, hand hygiene is a primary preventive measure. Hand washing with adequate quantities of soap and water, use of gloves, and disinfection are simple yet effective preventive measures (World Health Organization, 2000). Precautions in the preparation of food and potable water must be exercise. Swallowing of unknown sources of water should be avoided. Raw meat must be handled correctly by putting ground meat in the freezer before use. Meat must never be thawed at room temperature, but thawed by putting it in the refrigerator or in the microwave. Meat, such as ground beef must be cooked thoroughly, should not be pink and the juice should be clear. The temperature should be greater than 72 C. Raw meat must be separated from ready to eat foods. Work surfaces, dishes, utensils and hands touched by raw meat must be washed with warm soapy water. Unpasteurized milk or milk products should be avoided and only pasteurized milk, juice or cider must be consumed. Fruits and vegetables must be washed thoroughly. Children, elderly people and immunocompromised people should avoid consumption of alfalfa sprouts. People with diarrhoea must exercise personal hygiene, such as washing hands after bowel movements or changing soiled diapers and avoid sharing baths, preparing food for others, or swimming in public pools or lakes. If drinking water is drawn from a well, water intended for consumption must be boiled, the well must be disinfected, and water quality monitored (US Environmental Protection Agency, 2006). Conclusion E. coli are mostly harmless bacteria, but some strains can cause sickness, diarrhoea, urinary tract infections, pneumonia, and respiratory illness. Most E. coli infections can heal in 5 to 10 days without treatment. In the present case, the infection might have subsided in the individuals. However, individuals would be advised rest and symptoms continued to be monitored. Treatment should focus on the prevention of dehydration by the replacement of fluids and electrolytes. Patients treated for haemolytic uremic syndrome need supportive care, and if there is kidney failure, dialysis may be required. References Dixon, Jim et al. (2001). Task Force on Ecoli 0157. Available: http://www.food.gov.uk/multimedia/pdfs/ecolitaskfinreport.pdf. Last accessed 23 March 2009. Dowshen, S. (2007). E. coli. Available: http://kidshealth.org/kid/stay_healthy/food/ecoli.html. Last accessed 23 March 2009. MedicineNet. (2009). E. Coli 0157:H7 . Available: http://www.medicinenet.com/e_coli__0157h7/page3.htm. Last accessed 23 March 2009. National Center for Zoonotic, Vector-Borne, and Enteric Diseases (ZVED) . (2008). Escherichia coli. Available: http://www.cdc.gov/nczved/dfbmd/disease_listing/stec_gi.html. Last accessed 23 March 2009. National Kidney and Urologic Diseases Information Clearinghouse. (2009). NIH Publication No. 09–4570. Available: http://kidney.niddk.nih.gov/kudiseases/pubs/childkidneydiseases/hemolytic_uremic_syndrome/. Last accessed 23 March 2009. 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Available: http://www.nlm.nih.gov/medlineplus/ecoliinfections.html. Last accessed 23 March 2009. World Health Organization. (2000). Hospital hygiene and infection control. Available: http://www.who.int/water_sanitation_health/medicalwaste/148to158.pdf. Last accessed 24 March 2009. Yakub, Gary. (2004). Immunomagnetic Separation of Pathogenic Organisms From Environmental Matrices. Available: http://www.springerprotocols.com/Abstract/doi/10.1385/1-59259-766-1:189. Last accessed 23 March 2009. Read More