Vancomycin-Resistant Enterococci

VACOMYCIN-RESISTANT ENTEROCOCCI (VRE) IN THE AUSTRALIAN HEALTH-CARE SECTOR

This essay will look at Vancomycin-resistant enterococci and what it is. Why has Vancomycin become resistant? Vancomycin use of for medical treatment, transmission of and risks to acquiring VRE infections in the Australian health-care sector. Recommended precautionary measures used to prevent the spread of VRE amongst patients and health-care workers in the workplace. Why is it becoming more prevalent in Australian health-care sectors.

What is Vancomycin-resistant enterococci (VRE)? Vancomycin-resistant enterococci are enterococcus strains, such as Staphylococcus faecalis, now called Enterococcus faecalis that are resistant to the antibiotic vancomycin. Enterococci infections are the most common type acquired by hospitalised patients. Vancomycin was the last-line antibiotic for hospital treatment of serious methicillin-resistant staphylococcus aureus (MRSA) infections according to Collignon (2002, p. 327). These enterococci have become resistant because of the overuse of the antibiotics that control these infections. Cross-resistance between classes and exposure to one antibiotic may promote resistance to others. Changes to the bacterial receptors for these antibiotics in MRSA strains make them become resistant to methicillin and it derivatives. These changed receptors have limited activity to result in bacterial death when exposed to the antibiotics (Collignon, 2002).

The most frequent form of enterococci bacteria found in hospitals is E. faecium and E. faecalis, which are the two primary concerns of acquired resistance. According to Cetinkaya, Y, Falk, P & Mayhall, C, (pp. 687-688, 2002), there are five types of recognised phenotypes of vancomycin-resistance, Van A – E. faecium and E. faecalis, Van B- E. faecium, E. faecalis, Van C - E. gallinarum, E. casseliflavus and E. flavescens, Van D - E. faecium and Van E - E. Faecalis.

Antibiotics need to be used carefully and minimise the use of them. By vaccination, infection control measures and improved sanitation measures, antibiotic therapy could be reduced (Collignon, 2002). Vancomycin is given through a vein and used in the treatment of serious bacterial infections, such as skin infections, gynaecological infections, urinary tract infections and infections of the blood, bone, heart, or respiratory tract. Antibiotics should not be stopped early, they work best by using the medication as prescribed and until it is finished, otherwise the bacteria will continue to grow and the infection revert. Some of the risks for acquiring VRE infection are persons with weakened immune systems, the elderly, previously treated with vancomycin and combinations of other antibiotics, hospitalized and received antibiotic treatment over a long period, undergone surgical procedures, with medical devices such as catheters and intravenous catheters. Enterococcal infections are more common in elderly people, particularly those in long-term care facilities and skilled nursing homes because they are more likely to experience infection risk factors, such as exposure to medical instruments (Shiel, 2009).

The transmission of vancomycin-resistant enterococci is by person to person, particularly healthcare works whose hands may have been contaminated from feces, urine or blood and indirectly via hand contact with open wounds and contaminated surfaces. VRE cannot be transmitted through the air (Shiel, 2009). Control of these VRE infections is isolation to stop the spread to other patients, cleaning surfaces and the hygiene of healthcare workers, patients and visitors.

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Figure 1. Gram + cell envelope

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Figure 2. Gram – cell envelope

Enterococcus is gram-positive coccus that occur in short chains or pairs and are a component of normal human flora in gastrointestinal and genitourinary tracts (Christiansen et al, 2007). Appear roundish (spherical) in shape, generally thought of as non-capsulated, non-motile and non-spore forming. The cell wall (see Figure 1.) comprises most of the organisms weight made up of peptidoglycan, teichoic acid and polysaccharide, it also has surface proteins and the ability to form pili and ultimately a biofilm, it also lacks the outer membrane that gram-negative cells have and is a prokaryotic cell. Gram-negative enterococcus areprokaryotic cells, are rod shaped, the cell walls (see Figure 2.) are thinner than the gram-positive cell wall, contain relatively little peptoglycan and contains an outer membrane composed of lipopolysaccharide, lipoprotein and other complex macromolecules (Madigan, M, Martinko, M & Parker, J, 2003). VRE also occurs in gram-negative bacteria. For some of these resistant bacteria, there are few antibiotics available to treat these life-threatening infections according to Collingnon (2002, p. 325).

It is obvious that although many controls and regulations are implemented in the treatment and spread of VRE, these infections are still a problem. The most common factor is the overuse of antibiotics and hygiene. Clearly, it is essential that these treatments and infection controls need to be researched further and that the public needs to be made aware of the overuse of these antibiotics.

References:

Collignon, P. J. (2002). Antibiotic resistance. Medical Journal of Australia , vol. 177, 325-329.

Madigan, M, Martinko, M & Parker, J, 2003, Biology of Microorganism , 10th edn, Prentice Hall, New York.

Shiel, W, 2009, MedicineNet, Owned and Operated by WebMD and part of the WebMD Network.

Cetinkaya, Y, Falk, P & Mayhall, C, 2000, 'Vancomycin-Resistant Enterococci ', Clinical Microbiology Reviews, vol. 13, no. 4, pp. 686-707.

References: Collignon, P. J. (2002). Antibiotic resistance. Medical Journal of Australia , vol. 177, 325-329. Madigan, M, Martinko, M & Parker, J, 2003, Biology of Microorganism , 10th edn, Prentice Hall, New York. Shiel, W, 2009, MedicineNet, Owned and Operated by WebMD and part of the WebMD Network. Cetinkaya, Y, Falk, P & Mayhall, C, 2000, 'Vancomycin-Resistant Enterococci ', Clinical Microbiology Reviews, vol. 13, no. 4, pp. 686-707.