Pathogens must meet Koch's postulates................... "To test the purity of the pathogen you inject it into a host and the host should show symptoms of the disease"
Bacteria cause disease in order to benefit their own growth, for example mild tissue damage may release essential nutrients (e.g/ Iron - dependency of repression of toxin production in C. diptheriae).
Classification of Some pathogenic bacteria
Gram Pos+
Staph aureus, Staph epidermidis, Streptococci, Bacillus anthracis, Campylobacter jejuni.
Gram neg-
Heliobacter pylori, Neisseria gonorrhoeae, Escherichia coli, Klebsiella aerogenes, Pseudomonas aeruginosa, Campylobacter jejuni.
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Urinary tract infections are common in hospitals, how can health professionals reduce the risk of a urinary tract infection.
INTRODUCTION
This article is concerned with how a nurse in an acute care setting can minimise the risk of a urinary tract infection(UTI), with particular emphasis on urinary catheterisation. This article will describe an urinary tract infection, what organisms cause it, and how it can be minimised and treated. Urinary tract infections (UTI’s) are extremely common in hospitals and domicile settings, where they are a common hospital acquired infection (Rees & Williams, 1996). UTI’s are caused by bacteria and yeasts, infecting the urethra and bladder (Rees & Williams, 1996). Urinary tract infection is a common infection in women with about 35% having symptoms of a UTI at sometime in their lives. It is relatively uncommon in children and in men where it usually indicates underlying disease. One common form of a UTI in women is cystitis caused by a yeast infection (Candida albicans) which is a fungi (Ballinger & Patchett 1998).
PATHOGENESIS
Infection of the urinary tract is most often via the ascending transurethral route and this is facilitated by sexual intercourse and urethral catheterisation (Walsh, 1997). Women are susceptible to infection because of the short urethra and proximity to the anus this facilitates transfer of bowel organisms to the urethra and bladder. Infection is most often caused by bacteria from the patients own bowel flora or by nursing and medical staff not washing their hands before urethral catheterisation (Walsh, 1997). The most common microbial organisms causing UTI’s in hospitals are: (i) Escherisha coli (ii) Klebsiella aerogenes (iii) Enterocci (iv) Staphylococous saprophticus & Staph epidermis. (O’Neill, 1997). the most common bacteria found on patients, nurses and doctors skin is Staphylococous saprophticus, Staphylococous epidermis and Staphylococcus aureus. The other bacteria E.coli, Klebsiella and Enterocci are all found in human intestines and digestive tracts. Picture 1 (See appendices).
PATHOLOGY OF INFECTION
How does the microorganism infect and cause a urinary tract infection for a patient in an acute care setting.? If the nurse for example has not washed his/her hands thoroughly and touches the catheter before putting on gloves, this will contaminate the catheter tube with bacteria from the nurses hands. The pathogenesis of bacterial infection includes the initiation of the infectious process and the mechanisms that lead to the development of signs and symptoms of disease. Characteristics of bacteria that are pathogens include transmissibility, adherence to host cells, invasion of host cells and tissues, toxigenicity, and ability to evade the host’s immune system. Many infections caused by bacteria that are commonly considered to be pathogens are in apparent or a symptomatic. Disease occurs if the bacteria or immunologic reactions to their presence cause sufficient harm to the person (Jawetz, 1995). The five points below explain where bacteria can contaminate a closed urinary drainage system catheter. Urethral orifice, also called the meatal space and the pericathter space. Microorganisms entering via the urethral orifice travel along the potential space between the outer catheter surface and the urethral mucosa. It has to be remembered that the urethra has a natural bacterial flora of commensals, that is, it is colonised; some commensals are potentially pathogenic, and any injury by a catheter to the urethral mucosa will encourage the change of state from colonisation to auto-infection. Connection of catheter and drainage tube, the logical reasons for breaking this seal are when substance has to be injected into the bladder, or when a bladder washout becomes necessary. Bladder washout/irrigation is now acknowledged to be of dubious benefit (Stickler, 1990). Where a sample of urine has to be taken, a specimen of urine can be withdrawn by steadying the tube and piercing it with a sterile wider bored needle (14G) attached to a large sterile syringe. The nurse must have washed his/her hands to remove both resident and particularly transient flora, some of which may be pathogenic organisms, particularly in a hospital setting. Connection of drainage tube and collecting bag, it is necessary to break this seal when changing the collection bag, whether it is of the single use type, or of the reusable type in which there is an outlet at the base for emptying urine. Before separating the drainage tube and collecting bag, placement of a clamp on each, helps to minimise urine splash. The end of the drainage tube is always contaminated with bacteria from the air and nurses hands (Roe, 1993). Drainage of bag outlet, these are only present on the reusable bags. The results of one study indicated that nurses can contaminate their hands with microorganisms during bag emptying (Glenister, 1987). Diagram 2: A closed drainage system (See appendices). The signs and symptoms of a UTI are the patient will feel tender around the suprapubic area, there will be dysuria, pungent odour from urine, blue/green colour of urine (indicating pseudomonas infection) and there will be presence of leukocytes in the urine. Infection of the urinary tract can also occur during normal tolieting, for example how females wipe their anal regions after tolieting. The female must ensure to wipe front to back after defecation, in order to prevent any bowel organisms being transferred from the anus to the urethra, which frequently occurs if the genitalia are wiped back to front. The complications of a UTI in a fit patient with normal urinary function, is that a UTI rarely causes severe problems. However in patients with abnormal urinary tracts (e.g. Kidney stones) or systemic disease involving the kidney (e.g. diabetes mellutus), the complications can be renal papillary necrosis septicaemia or bacterima (Rees & Williams, 1996).
PREVENTION & MANAGEMENT OF UTI’S Management of ordinary UTI’s: The nurse has responsibilities for health promotion and patient teaching to decrease the development or recurrence of urinary tract infections in individuals at risk and to prevent and or decrease episodes of catheter or therapy induced UTI’s. The ward must be kept clean especially the toilets and bathing areas. Severely dehydrated patients needed to be assessed and encouraged to have a high fluid intake, to prevent stasis of urine in the bladder. If urine is kept in stasis in the bladder this encourages a UTI due to, providing a longer period of time for the bacteria to multiply and infect the bladder, rather than being passed away with each voiding by the patient. Passing of urine also keeps the urethra clear of any build up of bacteria, which in turn prevents the bacteria from the urethra from reaching the bladder. Since urinary tract infections can result from bacteria that originate in the gastrointestinal tract, frequent hand washing, especially after defecation, is an important preventive measure (Roe, 1993). Women should be taught to wipe their perineal areas from front to back and then dispose of the tissue. This avoid's contamination from the rectal area and should be practised after each bowel movement. Sexual intercourse is a contributing factor in the development of a UTI i women (Ballinger, 1998). For women who experience repeated UTI’s associated with sexual intercourse, both partners should wash their genitals prior to intercourse and the female should empty her bladder just before and again after intercourse. The use of condoms should be discussed, to help prevent bacteria from the man’s genitals, being passed to the women urethra. Management of Catheter UTI’s: Catheters are a major cause of UTI’s if not managed correctly, they allow entry of microorganisms in to the bladder, they offer a surface for the organisms to grow, they are a foreign body and therefore interfere with the bodies immune response. Catheters may cause chemical induced inflammation (due to the catheter material itself or by the lubricating gels used)of the urethral and bladder mucosa. Catheters also stretch the urethral orifice and injure tissues. Obstruction of a catheter produces increased intravesicular pressure, promoting the spread of organisms across the mucosa and up into the bladder, allowing colonisation and subsequent UTI. Patients from the community who are catheterised need to be educated about home care of their catheter, to prevent the occurrence of a UTI, which in turn prevents an admission to the ward. When catheterising a patient the nurse must use aseptic technique, aseptic technique is a method used to prevent contamination of wounds and other susceptible sites by organisms that could cause infection. This can be achieved by ensuring that only sterile equipment and fluids are used during invasive medical & nursing procedures (Pritchard & Mallett,1996). Aseptic technique methods: (1) Hand washing, this is the single most important procedure for preventing nonscomal infection as the hands have been shown to be an important route of transmission of infection (Casewell, 1977). It is very important to wash hands thoroughly with soap and continuously running hot water, before preforming aseptic technique and after patient contact. (2) No touch technique, is essential to ensure that hands even though washed, do not contaminate sterile equipment or the patient. This is usually achieved by the use of forceps or sterile gloves (Lascelles, 1982). (3) Inanimate objects, all instruments, fluids and materials that come into contact with the patient must be sterile if the risk of contamination is to be reduced. (4) Protective clothing must be worn for example when inserting a catheter tube. Protective clothing may be plastic aprons, which can be easily discarded after the procedure, thus reducing the risk of spreading any microorganisms to another patient. (5) The spread of infection is most likely to occur in a large open ward, due to currents of air blowing microorganisms across the open ward, thus catheterisation is normally carried out at a patient’s bed, with the curtains drawn( Curtains must be drawn for at least 10mins before procedure) this is so dust and air particles settle and are not being wafted around whilst catheterising. Sterile equipment when opened from their packaging must be kept to a minimum exposure to the air (Pritchard & Mallett, 1996). The nurse can help minimise the risk of a UTI, by 4-hourly washing of the perineum, of a catheterised patient, which would keep the natural flora within the limits with which the body defence system can cope (Pritchard & Mallett, 1992).
The management of a patient with a UTI would be a 5-day course of oral amoxycillian, nitrofuramitin or trinrthoprin (Rees & Williams, 1995). There should be individualised nursing care, patient education on prevention of infection. A high fluid intake should be encouraged during treatment and for some weeks after. Continues aseptic technique must also be used when inserting or replacing the urinary catheter or any of its connections, to minimise the risk of infection. CONCLUSION As discussed urine can be drained to the exterior through a tube (Catheter) inserted into the bladder via the urethra. An aseptic technique must be used in order to reduce the introduction of pathogenic microorganisms into the urinary bladder. Infection is common and potentially dangerous complication of catheterisation. Thus the nurse has an important role in teaching about cross-infection, procedures involving sepsis, sources of infection and nursing procedures where cross - infection is a risk, especially in urinary catheter care. Nursing staff and patients will need continually updating on new developments on managing urinary catheters correctly in order to reduce the risk of a UTI.
REFERENCES
Ballinger, A. Patchett, S. 1998. Clinical Medicine. London. Saunders Ltd.
Casewell, H. 1977. Hands as a route of transmission for Klebsiella species. British Medical Journal,2,1315 - 17.
Glenister, H. 1987. The passage of infection. Nursing Times, 83(22)June.3:68,71,73.
Jawetz, E. 1995. Medical Microbiology.20th ed. London. Prentice Hall.
Nursing Times, 1999. Practical Procedures for Nurses, 95 (12) March 24 -30.
O’Neill, D. 1997. The effect of temperature on the growth parameters of Klebsiella oxytoca. 3rd year Dissertation. University of Kent at Canterbury. Unpublished.
O’Neill, D. 1997. Human Microbial Infections. 3rdYear Project Work. University of Kent at Canterbury. Unpublished.
Pritchard, A.. Mallett, J. 1996. Manual of Clinical Nursing Procedures. 4th ed. Oxford. Blackwell.
Roe, B. 1993. Catheter - associated urinary tract infection - a review. Journal of Clinical Nursing 2:197 - 203.
Rees, P. Williams, D. 1996. Principles of Clinical Medicine. London. Edward Arnold.
Stickler, D. 1990. The role of antiseptics in the management of patients undergoing short term indwelling bladder catheterisation. Journal of Hospital Infection. 16:89 - 108.
Winn, C. 1996. Basic catheter care on research principles. Nursing Standard. 10 (18), 38 - 40.
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