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									                            University of Santo Tomas

                         Faculty of Medicine and Surgery

Comparative Study: Incidence of Asymptomatic UTI amongst Private and Public School

                                 Mary Anne M. Ilao

                                   Karina Dizon

                                   Lester Ibarra

                                Robe Ann V. Lopez

                                Cryscel A. Salonga

    I. Introduction

       In this world, where diseases come in the most unexpected places and where

microorganisms evolve every minute, man has to be aware and prepared for the most plebeian

to the most distinct infection he might acquire. The individuals susceptible to this kind of ailment

are teenagers who are becoming more experimental and curious about their surroundings.

Thus, most of this infection comes from the routine things we encounter daily. One of this is very

common, Urinary tract infection.

       A urinary tract infection (UTI) is a condition where one or more structures in the urinary

tract become infected after bacteria overcome its strong natural defenses. In spite of these

defenses, urinary tract infections are the most common of all infections and can occur at any

time in the life of an individual. Almost 95% of cases of urinary tract infections are caused by

bacteria that typically multiply at the opening of the urethra and travel up to the bladder (known

as the ascending route). Much less often, bacteria spread to the kidney from the bloodstream

(Greene et al, 2004).

       Urinary tract infections include a wide variety of clinical conditions.      These include

urethritis (inflammation of the urethra), cystitis (inflammation of the bladder), as well as acute

and chronic pyelonephritis (inflammation of the kidneys). Complications can include infections

around the kidney (perinephric abscess), bacteremia (microorganisms in the blood) and sepsis

(a severe illness usually with bacteremia and characterized by fever, fall in blood pressure and

confusion). UTIs in males may be complicated by prostatitis (inflammation of the prostate) and

epididymitis (inflammation of the tubes near the testicles) (Kunin et al, 2005).

        Bacterial UTIs can be classified according to localization as urethritis (urethra), cystitis

(bladder), or pyelonephritis (kidney).     In men, prostatitis may mimic or complicate UTI.

Alternatively, UTI can be classified by the presence (symptomatic) or absence (asymptomatic)

of symptoms, the frequency of its occurrence, the presence or absence of complications, and –

especially important in the elderly – whether UTI is associated with catheter use (Murphy et al.,


         Asymptomatic bacteriuria is characterized by ≥105 colony-forming units (CFU)/mL

without dysuria, urinary frequency, incontinence of recent onset, flank pain, fever, or other signs

of infection during the week preceding the time the urine sample was obtained. Small numbers

of polymorphonuclear leukocytes (PMNs) are common.            Only about 70% of asymptomatic

patients with high colony counts in a single urine sample have true bacteriuria as confirmed by

the second sample (Murphy et al., 2000).

         The prevalence of UTI increases in both sexes with age; the female:male ratio is 2:1 in

the elderly. The annual incidence of symptomatic bacterial UTIs is estimated to be as high as

10% in the elderly. However, because many of these infections are recurrent, the percentage of

infected patients is lower.    Asymptomatic bacteriuria is a common finding in the elderly,

especially in women; the estimated cumulative prevalence is 30% in women and 10% in men

(Murphy et al., 2000).

         Most UTI's occur in otherwise healthy females. There are many theories about how they

are acquired, but the most important point to remember, is that there is no reason to feel guilty

about having a UTI. There is virtually no evidence that activities of daily living such as diet,

clothing, urination habits, bathing, means of menstrual protection (napkins versus tampons),

direction of wiping after defecation, oral contraceptives and positions of heterosexual

intercourse are important factors (Kunin et al., 2005).

       The current screening tests are dipstick methods (incorporating leukocyte esterase (LE)

and nitrite level) and direct microscopy. The dipstick test has the advantages of speed, low cost

and that limited technical expertise is required. The LE test detects esterases released from

degraded white blood cells (WBC).          It is therefore an indirect measure of WBCs whose

presence is induced by urinary bacteria. The nitrite test detects nitrites produced by urinary

bacteria – usually limited to gram-negative organisms. Because both reactions require

concentrated urine, an early morning urine specimen is preferable. Conversely, microscopic

examination of urine for WBCs and bacteria provides direct evidence of their presence, but

there are varying standards and techniques. Specimens have been assessed uncentrifuged and

centrifuged as well as stained and unstained. WBCs have been counted per high power field

and in others per cubic milliliter. With these variations in technique, it is not surprising that there

have been inconsistencies in those studies evaluating the microscopic examination of urine

(Kunin et al., 2004).

       Debate continues regarding the best age at which to test a child. Theoretically, younger

children and infants should be the best candidates for screening on the assumption that such

screening would avert early renal scar formation. Unfortunately, the younger child is also the

most difficult from whom to obtain a "clean" specimen (Smith et al., 1996).

       This study aims to evaluate and determine the incidence rate of Asymptomatic Urinary

tract infection among Randomly Selected Students from public and private schools.

Statement of the Research Problem

       Asymptomatic urinary tract infection is an infection in which significant numbers of

bacteria (at least 100,000 bacteria per milliliter) have colonized the urinary tract without the

transpiration of any symptoms of the infection which in turn increase the risk of developing

symptomatic UTIs and other kidney problems. It can be classified as uncomplicated which are

only associated with bacterial infection or complicated which occur as a result of some

anatomical or structural abnormality (Simon et al., 1994).

        Urinary tract infections are about thirty times more common among females than males.

Silent infections (asymptomatic bacteriuria) occur in about 1% of schoolgirls and increase about

1% for each ten years of life.      Asymptomatic bacteriuria is detected by quantitative urine

cultures. Most authorities in the field agree that these silent infections (asymptomatic

bacteriuria) need not be treated in otherwise healthy girls, adult women and elderly men or

women. However, certain groups are at a higher risk for kidney infections if asymptomatic

bacteriuria is found via a urine test. Those at risk include people with diabetes, elderly people,

pregnant women – if asymptomatic bacteriuria is left untreated, up to 40% will develop a kidney

infection (pyelonephritis), Renal kidney transplant patients, young children with vesicoureteral

reflux, patients with infected kidney stones (Smith et al., 2005). There are several conditions in

which treatment of asymptomatic bacteriuria has proven to be highly effective. These include

after renal transplantation, following removal of an indwelling catheter, prior to urologic surgery

and during pregnancy (Kunin et al., 2005).

       Pyuria is present in almost all symptomatic and asymptomatic UTIs, and its absence

should strongly suggest another diagnosis. In female patients with typical symptoms of acute

cystitis, the presence of pyuria by urine dipstick testing is all that is required for a presumptive

diagnosis and a urine culture is unnecessary. Urine dipstick testing for the presence of

leukocyte esterase is a fast and relatively reliable way to identify pyuria. Leukocyte esterase is

an indirect measure of the presence of activated neutrophils. The enzyme is present in primary

neutrophil granules and reacts with a reagent on the dipstick to produce a color change. When

compared with gold standards such as the isolation of 105 CFU/ml of pathogenic bacteria, the

sensitivity ranges from 75 to 96 percent and specificity ranges from 94 to 98 percent. Screening

for asymptomatic bacteriuria is important during pregnancy, where there is strong evidence that

treatment is efficacious in improving outcome.

    II. Objectives

General Objective:

       This study aims to evaluate the Incidence Rate of Asymptomatic Urinary Tract infection

among selected students of a public school in comparison to private school.

Specific Objectives:

   1. To collect randomly voided midstream clean catch urine specimens from volunteer

       subjects from students of public and private schools.

   2. To screen for asymptomatic urinary tract infection using dipstick tests with the leukocyte

       esterase and nitrite content as parameters.

   3. To confirm results of positive (leukocyte and nitrite) urine samples by counting the

       number of leukocytes per high power field.

   4. To compute for the incidence rate of asymptomatic Urinary Tract Infection among the

       positive result.

   5. To compare the incidence rates of asymptomatic urinary tract infection.

    III. Theoretical Framework

       A urinary tract infection (UTI) refers to an infection anywhere in the urinary tract. The

urinary system includes the kidneys, ureters, bladder and the urethra.

       The most common types of urinary tract infections affect the bladder and kidney. When

the bladder is infected, it means that the pathogens have only made it to the bladder not up to

the kidneys. Symptoms of bladder infections are: having to urinate more often, not being able to

wait to urinate and a burning feeling during urination. Children who have a bladder infection may

not be able to hold their urine (incontinence). They may also have lower abdominal pain and a

mild fever.

       Children who have a kidney infection usually feel worse because of a high fever and

pain on their back, usually on one side. Kidney infections often start out as bladder infections

that move up into the kidneys (Ross et al., 1999).

       When a person has no symptoms of infection but significant numbers of bacteria have

colonized the urinary tract, the condition is called asymptomatic urinary tract infection which in

turn increases the risk of developing symptomatic urinary tract infection.

       In most cases, bacteria first begin growing in the urethra. This infection is called

urethritis. From there bacteria often move on to the bladder, causing a bladder infection

(cystitis). If the infection is not treated promptly, bacteria then may go to the ureters to infect the

kidneys (pyelonephritis).

       Most infection arises from one type of bacteria, Escherichia coli, which normally lives in

the colon. Microorganisms called Chlamydia and Mycoplasma may also cause urinary tract

infections in both male and female, but these infections tend to remain limited to the urethra and

reproductive system. It can also be transmitted through sexual contact unlike the infection

caused by Escherichia coli.

       In diagnosis of urinary tract infection, examination should be carefully observed. Dipstick

urine test can detect urinary protein, blood, nitrites and leukocytes esterase. This test is used for

screening and specimens tested positive should be sent for microscopic analysis and culture for

affirmation (Smith et al., 1994).

    IV. Significance of the Study

       Asymptomatic bacteriuria is an infection common to people especially children. This

occurs in different age bracket. Unfortunately, detection is difficult due to the absence of

symptoms on people who have the infection. Prevention and treatment may not be given in this

case. The only symptom that may occur may be too late and the infection may spread.

       In some people, asymptomatic bacteriuria eventually progresses to a full-blown infection,

with the usual symptoms (Kunin et al., 2005).

       According to the studies of Sox et al. in 1996 asymptomatic bacteriuria may precede

symptomatic urinary tract infection, characterized by dysuria, frequency, pain, fever, etc., which

accounts for over 6 million outpatient visits each year. Urinary tract infection may be associated

with renal insufficiency and increased mortality in adults, but these complications rarely occur

among those without underlying structural and functional diseases of the urinary tract. In both

institutionalized and noninstitutionalized elderly, urinary tract infection is the most common

cause of bacteremia, which may be associated with a 10-30% case fatality rate. Most such

bacteremia occurs in residents with indwelling catheters or urinary tract abnormalities, however.

Similarly, most of the 300,000 hospitalizations each year for urinary tract infections involve

patients with indwelling urethral catheters.

       In children, asymptomatic bacteriuria may be a sign of underlying urinary tract

abnormalities. About 10-35% of infants and children with asymptomatic bacteriuria have

vesicoureteral reflux and 6-37% have renal scarring or other abnormalities (the lower

prevalences generally reflecting more stringent definitions of abnormality), whereas such

abnormalities are uncommon in the general population of children.           Children with major

structural abnormalities, chronic pyelonephritis, or severe vesicoureteral reflux are at increased

risk of renal scarring, obstructive renal atrophy, hypertension, and renal insufficiency.

Pyelonephritis, reflux nephropathy, and urinary tract malformations may cause as much as one

fifth of cases of renal failure in children. In pregnancy, 13-27% of untreated women with

asymptomatic bacteriuria develop pyelonephritis, usually requiring hospitalization for treatment.

Bacteriuria in pregnant women increases the risk for preterm delivery and low birth weight about

1.5-2-fold, and may also increase the risk of fetal and perinatal mortality (Sox et al., 1996).

       The risk of acquiring bacteriuria varies with age and sex. Asymptomatic bacteriuria in

term infants is more common in males (estimated prevalence of 2.0-2.9% vs. 0.0-1.0% in

females), but it is considerably more common in girls after age 1 (0.7-2.7% in girls vs. 0.0-0.4%

in boys). Approximately 5-6% of girls have at least one episode of bacteriuria between first

grade and their graduation from high school, and as many as 80% of these children experience

recurrent infections. Asymptomatic bacteriuria in adulthood is more prevalent in women than

men (3-5% vs. <1% in those under 60 years), and its prevalence increases with age.

Asymptomatic bacteriuria is a common finding in older persons, especially those who are very

old (20% of women and 10% of men >80 years old living in the community) or institutionalized

(30-50% of women and 20-30% of men). Bacteriuria occurs in 2-7% of pregnant women; of

those who are not bacteriuric at initial screening, 1-2% will develop bacteriuria later in the

pregnancy (Sox et al., 1996).

       The study may help establish the occurrence of Asymptomatic UTI among public and

high school students. The Dipstick test and microculture will determine the organisms and

causing of urinary tract infection (Sox et al., 1996).

       The diagnosis of Asymptomatic Urinary tract infection has become increasingly

important because of the difficulty in the determination of the presence or absence of true

urinary tract infection (Ross et al., 1999).

       The issue of “asymptomatic bacteriuria” is an often misunderstood one. It is well

established that asymptomatic bacteriuria is common, difficult to eradicate and of no

significance to patient in the absence if vesicourethral reflux or other urinary tract anomalies

(Ross et al., 2000).

        The potentially harmful practice of “routine cultures” in asymptomatic patients with a

history of UTI is widespread and should be discouraged. These cultures, if positive, will lead to

the inappropriate treatment of bacteriuria. This exposes the child to unnecessary antibiotics and

select resistant organisms, which will make future symptomatic infections difficult to treat (Ross

et al., 2000).

        Screening for Asymptomatic bacteriuria was undertaken with the belief that early

detection of infection and the identification of the structural abnormalities coupled with the

appropriate management might lead to prevention of pyelonephritis and renal damage (Kumar

et al., 2002).

        With the detection of the infection, treatment may be given at early stage. Prevention

may also be given prior to the infection.

        This research provides information and data to help assess the prevalence rate of

urinary tract infections especially those who attend classes in public and private high schools.

Information from this research may help researchers to find ways or innovations in preventing

and treating this kind of illness.

        The relevance of the study is that it will serve as a reference and as an information

campaign to researchers and people that may be beneficial to science and to man.

    V. Scope and Limitations

        The subjects for the study will include a total of 200 volunteers from both public and

private high school (34 first year students; 33 second year students; 33 third year students)

(Briones personal communication, July 2005). Only students showing no symptoms will be

accepted as samples. This will be done with the aid of the school’s physician and through a set

of questionnaire that will be distributed by the researchers.

       The study will be using midstream urine specimen (MSU) because the initial flow of urine

in effect flushes out normal flora from the urethra, thus, providing less contamination and

interference during the testing proper.

       The urine specimen will be tested by the dipstick method using ten parameters

(leukocyte, urobilinogen, nitrite, protein, pH, blood, specific gravity, ketone, bilirubin, glucose).

Only two trials per sample will be done due to time and financial constraints. Specimens will

undergo routine urinalysis in order to further evaluate the infection. Only white blood cells will be

reported in the microscopic exam and only those specimens that contain 5 and above

leukocytes per high power field will be reported as positive with urinary tract infection.

    VI. Definition of Terms

   1. Urinary tract infection - condition where one or more structures in the urinary tract

       become infected after bacteria overcome its strong natural defenses

   2. Asymptomatic urinary tract infection – a type of urinary tract infection that shows no


   3. Symptomatic urinary tract infection – another type of urinary tract infection that shows

       signs/symptoms of infection.

   4. Cystitis – bacterial infection of the bladder

   5. Pyelonephritis – bacterial infection of the kidneys

   6. Urethritis – bacterial infection of the urethra

   7. Vesicourethral reflux - This is a structural defect of the valve-like mechanism between

       the ureter and bladder that allows urine to flow backward, carrying infection from the

       bladder up into the kidneys

   8. Prostatitis – inflammation of the prostate

   9. Leukocyte – another term for white blood cells; cells of the immune system defending

       the body against both infectious disease and foreign materials

   10. Nitrite – produced by bacterial reduction of urinary nitrate

   11. Pyuria – presence of pus cells in the urine

   12. Bacteremia – presence of bacteria in the circulation

   13. Bacteriuria – presence of bacteria in the urine

   14. Dysuria – painful urnation

   15. Escherichia coli- predominant species of gram-negative bacilli (GNB) in the colonic flora;

       the single most common pathogen for all UTI syndrome.

    VII.    Hypothesis

       Incidence rate of asymptomatic urinary tract infection among high school students in

public school is greater in number than that of students in private school.

    VIII.   Review of Related Literature

       Acute infections of the urinary tract fall into two general anatomic categories: lower tract
infection (urethritis and cystitis) and upper tract infection (acute pyelonephritis, prostatitis, and
intrarenal and perinephric abscesses). Infections at various sites may occur together or
independently and may either be asymptomatic or present as one of the clinical syndromes
described in this chapter. Infections of the urethra and bladder are often considered superficial
(or mucosal) infections, while prostatitis, pyelonephritis, and renal suppuration signify tissue

       From a microbiologic perspective, urinary tract infection (UTI) exists when pathogenic
microorganisms, usually E. coli, are detected in the urine, urethra, bladder, kidney, or prostate.
In most instances, growth of >105 organisms per milliliter from a properly collected midstream
"clean-catch" urine sample indicates infection. Colony counts of >105/mL in midstream urine are

occasionally due to specimen contamination, which is especially likely when multiple bacterial
species are found.

       Epidemiologically, UTIs are subdivided into catheter-associated (or nosocomial)
infections and non-catheter-associated (or community-acquired) infections. Infections in either
category may be symptomatic or asymptomatic. Acute community-acquired UTIs are very
common and account for more than 7 million office visits annually in the United States. In the
female population, these infections occur in 1–3% of schoolgirls and then increase markedly in
incidence with the onset of sexual activity in adolescence. The vast majority of acute
symptomatic infections involve young women; a prospective study demonstrated an annual
incidence of 0.5–0.7 infections per patient-year in this group. In the male population, acute
symptomatic UTIs occur in the first year of life (often in association with urologic abnormalities);
thereafter, UTIs are unusual in male patients under the age of 50. The development of
asymptomatic bacteriuria parallels that of symptomatic infection and is rare among men under
50 but common among women between 20 and 50. Asymptomatic bacteriuria is more common
among elderly men and women, with rates as high as 40–50% in some studies. The incidence
of acute uncomplicated pyelonephritis among community-dwelling women 18–49 years of age is
28 cases per 10,000 women.

   About one-third of women with dysuria and frequency have either an insignificant number of
bacteria in midstream urine cultures or completely sterile cultures and have been previously
defined as having the urethral syndrome. About three-quarters of these women have pyuria,
while one-quarter have no pyuria and little objective evidence of infection. In the women with
pyuria, two groups of pathogens account for most infections. Low counts (102–104/mL) of typical
bacterial uropathogens such as E. coli, S. saprophyticus, Klebsiella, or Proteus are found in
midstream urine specimens from most of these women. These bacteria are probably the
causative agents in these infections because they can usually be isolated from a suprapubic
aspirate, are associated with pyuria, and respond to appropriate antimicrobial therapy. In other
women with acute urinary symptoms, pyuria, and urine that is sterile (even when obtained by
suprapubic aspiration), sexually transmitted urethritis-producing agents such as Chlamydia
trachomatis, Neisseria gonorrhoeae, and herpes simplex virus are etiologically important. These
agents are found most frequently in young, sexually active women with new sexual partners

    IX. Ethical Considerations

        The principle of autonomy is the main ethical issue that needs to be addressed in this
study. If the patient is willing to participate she should sign the informed consent (Appendix)
given to her, and if not she should not be forced by the researchers for this will violate the
principle of autonomy.

        The principle of beneficence should also be addressed in this study. The participant
should be treated and followed-up if the result of the urine specimen needs special attention and
        The Declaration of Helsinki (Appendix) should be taken into consideration in this study
since it includes human subjects.

    X. Time Schedule

    Activities        1st     2nd      3rd      4th      5TH     6TH      7th      8th     9th
                     week    week     week     week     week    week     week     week    week
Accomplishment         *       *        *
   of consent
 School hunt (1          *      *       *
  private and 1
Buying of                       *       *        *        *
(dipstickm urine
cups, gloves
   Experiment                                    *        *        *       *
  Gathering of                                   *        *        *       *
  Data analysis                                  *        *        *       *
   Final paper           *      *       *        *        *        *       *        *        *
      others                                                                                 *

    XI. Budget

           Materials/ professional fee/others              Amount

       Urine cups                               4000php

       Disposable gloves                        250php

       Disposable masks                         250php

       Medical technologist fee                 30000php

       Miscellaneous                            5500php

       Total                                    40000php

*alternative – dipstick method – 6000php

    XII.   Bibliography

1. U.S. Preventive Services Task Force; Guide to Clinical Preventive Services, 2nd ed.
Washington, DC: Office of Disease Prevention and Health Promotion; 1996.

2. Hagay Z, Levy R, Miskin A, Milman D, Sharabi H, Insler V. Uriscreen, a rapid
enzymatic urine screening test: useful predictor of significant bacteriuria in pregnancy.
Obstet Gynecol 1996;87:410-3.

3. Abrutyn E, Mossey J, Berlin JA, et al. Does asymptomatic bacteriuria predict mortality
and does antimicrobial treatment reduce mortality in elderly ambulatory women? Ann
Intern Med 1994;120:827-33.

4. Abrutyn E, Berlin J, Mossey J, Pitsakis P, Levison M, Kaye D. Does treatment of
asymptomatic bacteriuria in older ambulatory women reduce subsequent symptoms of
urinary tract infection? J Am Geriatr Soc 1996;44:293-5.

5. Smaill F. Antibiotics for asymptomatic bacteriura in pregnancy. The Cochrane Library.
Oxford: Update Software; 2002: 3.

6. Villar J, Lydon-Rochelle MT, Gulmezoglu AT, et al. Duration of treatment for
asymptomatic bacteriuria during pregnancy. The Cochrane Library Oxford: Update
Software; 2002: 3.

7. Avorn J, Monane M, Gurwitz JH, Glynn RJ, Choodnovskiy I, Lipsitz LA. Reduction of
bacteriuria and pyuria after ingestion of cranberry juice. JAMA 1994;271:751-4.

8. Rouse DJ, Andrews WW, Goldenberg RL, Owen J. Screening and treatment of
asymptomatic bacteriuria in pregnancy to prevent pyelonephritis: a cost-effectiveness
and cost-benefit analysis. Obstet Gynecol 1995;86:119-23.

10. Kass EH. Asymptomatic infections of the urinary tract. Trans Assoc Am Physiol.
1956; 69:56-64.

11.Hyman ES. Computer algorithm offers a comprehensive view of bacteriuria.
Nephron. 1993; 65:549-58.

12. Kaye D. Antibacterial activity of human urine. J Clin Invest. 1968; 47:2374-90.

XIII.   Appendix

A. Consent Form (attached)

B. Dummy Tables


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