Risk Groups for Urinary Tract Infections - Essay Example

Risk Groups for Urinary Tract Infections Urinary Tract Infection is the invasion of the tissues that make up the urinary tract system by microbial organisms. The infection of the human urinary tract is a major symptom for the contemporary experimental microbial treatment in both primary and secondary care. Additionally, the number of urine samples when compared with the other typical specimens in the field of medical microbiology laboratories is very large. In normal human condition, the urinary tract is sterile though the infections can result from different conditions. The infections can either be simple, complicated, symptomatic, or asymptomatic. Clinical physicians in medical microbiology categorize urinary tract infections into upper and lower tract infections on an anatomical basis. An infection of the bladder refers to cystitis and where the infection spreads to other areas, such as, the ureters and the kidneys, the infection is pyelonephritis. Cystitis is, therefore, regarded as the lower urinary tract infection while pyelonephritis is the upper urinary tract infection. The latter is more severe and complicated than the former. In spite of the availability of several antibacterial factors such as urea concentration, pH, salt content of the urine, osmolality, and other urinary tract inhibitors of bacterial adherence, several bacteria are still able to invade the urinary tract system. The bacteria predispose the patients to a variety of urinary tract infections. The common types of bacteria that correlate with a diverse range of urinary tract infections are the Gram negative bacteria of E. coli and Klebsiella species. The uropathogenic bacteria overcome the several urinary inhibitors to bacterial invasion such as the Tamm-Horsfall protein (THP), lactoferrins, low-molecular weight oligosaccharides, bladder mucopolysaccharides, and secretory IgA. The bacteria, however, still adhere, grow, multiply, and resist against the host’s defence mechanisms even with the presence of bacteria inhibition factors and conditions. The result is massive colonization and subsequent urinary tract system infection (Stamm 2006, p. 2-4). The paper aims at reviewing the numerous bacteria that are responsible for the various urinary tract infections. It also highlights the laboratory diagnostic routine procedures used in the diagnosis of the bacteria in the most prone population groups, as well as, the infections exhibited by the general population. Bacteria that may cause urinary tract infections Many researchers and scholars in microbial urinary tract infections agree that the Gram negative bacteria of E. coli and the bacteria associated with the Klebsiella species are the common organisms that cause urinary tract infections in both males and females. In fact, E. coli accounts for between 70-90% of both upper and lower urinary tract infections (Kilmartin 2002, p. 38). The E. coli is responsible for many uncomplicated cases of cystitis in females, particularly the young women. The bacteria are usually harmless with its origin being the intestines. When the bacteria invade the urinary tract, they can colonize the bladder and result to infections. Enterococci, proteus mirabilis, and Staphylococcus saprophyticus are other forms of bacteria that are responsible for between 5 to15% of urinary tract infections, particularly at an early age in females (Irwin & Rippe 2008, p. 6-7). Some rare bacteria that cause some forms of urinary tract infections are the Mycoplasma hominis and Ureaplasma urealyticum. They are typically harmless organisms. Citrobacter also associates with some complicated forms of urinary tract infections that relate to structural or physical conditions. Other forms of bacteria that cause complicated and severe urinary tract infections are the Enterobacter, aeruginosa, and the Serratia species bacteria including the Enterococcus species. Risk Factors and Risk groups for urinary tract infections Some of the major risk factors that associate with urinary tract infections include; genetic predisposition, behavioural factors, frequency of urination, urologic structural abnormalities, and the antibacterial activity of prostatic fluid (in males). Other predisposing factors include; the lack of personal hygiene, use of birth control pills, diabetes, pregnancy conditions, hypertension, immune-suppression, low concentration of lactobacilli in older females, stone formation, and instrumentation such as catheterization during medical procedures. Research studies indicate that females are more susceptible to these infections than their male counterparts. Re-infections tend to occur more in women than in men because the urethra is longer in men and shorter in women. The use of contraceptive spermicides and diaphragm are other risk factors that make women more susceptible to urinary tract infections than men (Foxman 2005, p. 5). Numerous research studies highlight that urinary tract infections in females are common. One in five women suffers from a form of urinary tract infection in their lifetime. On a clinical perspective, the issue of urinary tract infection among women is a recognized global problem. When women attain the menopause age, there is a substantial decrease in oestrogen. Oestrogen protects the interior lining of the urinary tract and its decrease will, therefore, increase their susceptibility to bacterial urinary tract infections. Although pregnancy does not exacerbate the development of urinary tract infections, evidence suggests that it exacerbates the risk of developing some serious infections that can potentially harm the mother and the foetus. Pregnant women should, therefore, report any symptoms of urinary tract infections to their medical supervisors for timely screening for asymptomatic bacteria (Clarridge, Johnson & Pezzlo 2001, p. 18). Individuals who suffer from spinal cord injuries and severe nerve damage around the bladder area have difficulties in emptying their bladders. Consequently, bacteria get the chance to grow and multiply within the urine that over-stays within the bladder. Individual who have abnormalities of the urinary tract, for example risk developing some form of urinary tract infections. People suffering from diabetes and those with issues in their body’s natural defence mechanisms are susceptible to urinary tract infections. Another primary cause of infections along the urinary tract stems from the use of tubes or catheters placed in the urethra or bladder. The devices interfere with the body’s ability to remove microbes from the urinary tract. The bacteria, as a result, travel around or through the instruments until they establish an area where they can grow and thrive. It is plausible to note that unconscious or critically ill individuals cannot urinate in a regular manner. The condition necessitates the need for catheters in order to aid the process of emptying the bladder. Medical scholars, therefore, emphasize on limiting the use of such devices to the minimum time possible (Carroll et al. 2004, p. 102). The various methods used in microbiology laboratories for the identification and characterization of the several bacteria involved in the causation of urinary tract infections include Gram stain followed by motility testing, biochemical test and microscopic examinations. The Enteric bacteria, particularly the E. coli, remain the common cause of urinary tract infections. It accounts for a large percentage of the workload in clinical microbiology laboratories. Although the E. coli bacteria are the most frequent causes of urinary tract infections, the distribution of the pathogens that cause urinary tract infections is changing significantly. Of great importance is the increase in resistance to several antimicrobial agents, particulary the resistance to trimethoprim-sulfamethoxazole as is the case with E. coli (Andriole 2005, p. 94). Clinical physicians distinguish urinary tract infections from other infections that bear similar clinical signs through the use of a small number of combined clinical tests. None of the several tests when used individually would offer adequate specificity and sensitivity. In the category of the diagnostic tests, urinalysis remains useful especially for the exclusion of bacteraemia. The urine culture is not always necessary as part of clinical evaluation of out-patients who show uncomplicated urinary tract infections. It is necessary for the out-patients who demonstrate recurrent cases of urinary tract infections or those patients who exhibit complicated cases of urinary tract infections. The urine culture is also important in the evaluation of in-patients who develop urinary tract infections within the clinical set-up. Urinary tract infections pose serious challenges for clinical practitioners due to the large number of cases that are reported every year and the fact that urinary tract infections are not a straightforward undertaking. It, therefore, means that physicians have to differentiate urinary tract infections from other types of infections that have similar clinical manifestations. Some urinary tract infections, for example, may be present with atypical symptoms. It means that the diagnosis of such infections in patients who do not often have pyuria may call for different diagnostic criteria compared to those employed for the evaluation and diagnosis of the general patient population (Ayhan, Basbug & Ozturk 2006, p. 217). The detection, characterization and investigation techniques used in medical microbiology laboratories for the various bacteria that cause urinary tract infections are as discussed below. Medical investigation of bacteriuria by urine microscopy Bacteriuria often detects microscopically through the Gram staining of un-centrifuged urine specimens. The bacteria also identifies through Gram staining of centrifuged urine specimens or direct assessment of bacteria within the urine specimens. The Gram stain of un-centrifuged specimens is not a complicated process. The medics apply a small volume of the urine sample on a glass microscope slide, left to air-dry, stained with the Gram stain, and then evaluated microscopically. The performance dynamics of this test are not well-defined because different criteria define a positive test result. Some investigators have also shown that the test has low sensitivity levels for accurate detection and characterization of urinary tract infections (Rane & Dasgupta 2013, p. 10). Detection and investigation of bacteriuria by nitrite test Bacteriuria also detects chemically in cases where the bacteria produce nitrite from nitrate. The resultant biochemical reaction that becomes detectable through the nitrite test associates with members of bacteria family known as the Enterobacteriacea. The effectiveness of the test is, however, limited because nitrite production is always associated with other urinary tract pathogens such as S. saprophyticus, enterococci, and the Pseudomonas species. Another critical limitation of the analysis is that it needs the testing specimen to be part of the first urine produced in the early morning hours. The reason for that is because it takes not less than four hours for the bacteria to form nitrite from nitrate in substantial levels that are clinically detectable (Leppert & Peipert 2009, p. 44). Investigation of pyuria through urine microscopy Pyuria identifies and subsequently quantified by analysing the rate of urinary leukocyte secretion. Counting the number of leukocytes by use of a hemocytometer, counting of the leukocytes in a centrifuged specimen, or counting of the leukocytes present in urine specimens by way of Gram staining also gives good results. The advantage of such investigative techniques compared to urine microscopy methods is that the physician can observe the leukocytes and leukocyte casts, as well as, other cellular elements. The main disadvantage of the techniques compared to urine microscopy techniques is that the leukocytes deteriorate very fast in urine samples that are not fresh or urine specimens preserved adequately. Each of these tests has some disadvantages that obscure their usefulness as a standard clinical testing method. Due to such disadvantages, technologists limit urine microscopy to patients with pyelonephritis or other complicated infections (West 2012, p. 3-5). Investigation of pyuria through leukocyte esterase tests The leukocyte esterase tests derive from ester substrates through hydrolysis of proteins that exhibit ester lytic activity. Typical human neutrophils secrete as many as ten proteins that show ester lytic activity. The proteins then react with ester substrates resulting in the production of acids and alcohols. The substances then react with other chemical substances to produce colour changes that are proportional to the amount of esterase present in the specimen. The tests bear the power of detecting esterase released following cell lysis. Sample specimens that have not been adequately preserved in a proper manner also have the potential to produce positive test results. Leukocyte esterase tests can, however, produce false-positive results. The false tests occur when the urine specimen contaminates with bacteria that may be present in vaginal fluids. It can also occur when the specimen contains Trichomonas species or eosinophils. Numerous clinical researchers prov that the use of esterase tests alone is ineffective because of the relatively low specificity and sensitivity of the tests (Kunin 2007, p. 12-15). The tests also show low positive predictive values as a test for urinary tract infections, with high predictive values. Conclusion Various forms of urinary tract infections result from an array of bacteria species and the predisposing factors for these diseases are also diverse. The methods used in the detection and investigation of the microbial organisms that responsible for urinary tract infections vary with the bacteria suspected to be responsible for the various clinical signs and symptoms exhibited by the patient. Many patients who suffer from uncomplicated acute cystitis highlight cases that are straightforward from a clinical perspective. Such cases do not require complex laboratory testing procedures apart from simple urinalysis. Significant portions of patients, physical findings and clinical history may be insufficient to arrive at definitive diagnosis of urinary tract infections. Laboratory tests are, therefore, pivotal when undertaking the diagnosis in patients with complicated urinary tract infections. They provide specific information pertaining the identity and antimicrobial susceptibility pattern of the involved pathogens. Reference List Andriole, T 2005, The role of Tamm-Horsfall protein in the pathogenesisof reflux nephropathy and chronic pyelonephritis. Yale: Journal of Biological Medicine, 58: 91-100. Ayhan, N, Basbug, N & Ozturk S 2006, Causative agents of urinary tract infections and sensitivity to antibiotics. Microbiology Bulletin, 22 (3): 215-221. Carroll C, Hale, C, Von, H, Reich C, Hamilton, T & Matsen, M 2004, Laboratory evaluation of urinary tract infections in an ambulatory clinic. American Journal of Clinical Pathology, 101:100-3. Clarridge, J, Johnson, R & Pezzlo T 2001, Laboratory diagnosis of urinary tract infections. American Society for Microbiology; 1998. Foxman, B 2005, Epidemiology of urinary tract infections: incidence, morbidity, and economic costs American Journal of Medicine.113:5-13. Irwin, R &Rippe, J 2008, Irwin and Rippe's Intensive Care Medicine. Lippincott Williams & Wilkins, New York. Kilmartin, A 2002, The Patient's Encyclopaedia of Urinary Tract Infection, Sexual Cystitis and Interstitial Cystitis. Angela Kilmartin, New York. Kunin, C 2007, Urinary tract infections: detection, prevention, and management. Lippincott Williams & Wilkins, Michigan Leppert, P & Peipert, J 2009, Primary Care for Women. Lippincott Williams & Wilkins, New York Rane, A & Dasgupta, R 2013, Urinary Tract Infection: Clinical Perspectives on Urinary Tract Infection. Springer Science & Business, New York Stamm, W. 2006, Scientific and clinical challenges in the management of urinary tract infections. American Journal of Medicine; 113:1-4. West, K 2012, Urinary Tract Infections. The Rosen Publishing Group, London Read More