Các yếu tố nguy cơ của nhiễm trùng tiết niệu tại bệnh viện

ABBREVIATIONS

CAUTIs

: Catheter-associated urinary tract infections

CDC

: Centers for Disease Control and Prevention

CI

: Confidence interval

ICU

: Intensive care unit

PR

: Prevalence ratio

UTI

: Urinary tract infections

WHO

: World Health Organization

LIST OF FIGURES AND TABLES
Trang
ABBREVIATIONS
.................................................................................................................................
1
CAUTIs : Catheter-associated urinary tract infections
.................................................................................................................................
1
CDC : Centers for Disease Control and Prevention
.................................................................................................................................
1
CI : Confidence interval
.................................................................................................................................
1
ICU : Intensive care unit
.................................................................................................................................
1
PR : Prevalence ratio
.................................................................................................................................
1
UTI : Urinary tract infections
.................................................................................................................................
1
WHO : World Health Organization
.................................................................................................................................
1


LIST OF FIGURES AND TABLES
.................................................................................................................................

2
Trang
.................................................................................................................................
2
CONTENTS
.................................................................................................................................
8
Trang
.................................................................................................................................
8
INTRODUCTION
.................................................................................................................................
1
Objectives of the study...........................................................................................................3

CHAPTER 1. LITERATURE REVIEW
.................................................................................................................................
4
1.1. Nosocomial infections.....................................................................................................4
1.1.1. Definition of nosocomial infections.............................................................................4
Nosocomial infections are infections acquired during hospital care of patients. Infections
occurring more than 48 hours after admission are usually considered nosocomial infections.
Nosocomial infections could be classified into different categories in terms of infectious sites.
These are derived from those published by the Centers for Diseases Control and Prevention
(CDC) in the United States of America or during international conferences [28] and are used for
surveillance of nosocomial infections. Recently, about 50 types of nosocomial infections with
biological and clinical characteristics are identified....................................................................4
1.1.2. Epidemiology of nosocomial infections.......................................................................4

1.1.3. Types of nosocomial infection......................................................................................5
1.2. Urinary tract infection.....................................................................................................7
As mentioned above, UTIs are one of the most frequent nosocomial infections. According to
Craven, UTIs account for about 40% of all nosocomial infections in US hospitals each year [17].
UTIs often occur in ICU, outpatient or inpatient ward, and rehabilitation ward.........................7
The prevalence and mortality rate of UTIs vary among countries. In US, according to CDC
the prevalence of UTIs in 2002 was 17% of total cases of nosocomial infections; of these there
were 10% deaths, 5% cases developed bacteraemia. In European and Asian countries, the
incidence of UTIs fluctuated from 3.5 to 9.9% each year [45]....................................................7
Most of UTIs are associated with the utilization of an indwelling urinary catheter. In US,
there are 80% UTIs related to catheterization in patients with prolonged hospital stay [37]. In
2012, a review study investigated 4,109 studies worldwide showed that the attributable risk of
CAUTIs could be about 79.3% [35]. One study of Karina in Philippine found that the prevalence
of CAUTIs in a General Hospital raised up to 54.4% [34]. Mai Thi Tiet in her study in 2011
concluded that there were 26/41 patients (63.4%) acquired CAUTIs [8]....................................7
The prevalence of CAUTIs at ICU was highest, followed by internal medicine ward and
surgical ICU. CAUTIs do not only occur at hospital but at patient’s home after they are
discharged from hospitals. Beaver in his study in 2008 found that patients with indwelling
urinary catheter at home had the risk of acquiring CAUTIs between 2.1 and 6.7 days/1000 days
of catheterization [12]..................................................................................................................7
1.3. Catheter-associated urinary tract infection......................................................................8
1.3.1. Etiology........................................................................................................................8
1.3.2. Pathogenesis.................................................................................................................9
1.3.3. Clinical manifestations of CAUTIs..............................................................................9
1.3.5. Diagnosis of CAUTIs.................................................................................................11
1.4. Risk factors for CAUTIs...............................................................................................17
1.4.1. Demographic characteristics of patients.....................................................................17
1.4.2. Factors related to health condition of patients............................................................17
1.4.3. Factors related to patient’s illness..............................................................................17

1.4.4. Factors related to catheterization................................................................................18
1.4.5. Factors related to catheter characteristics...................................................................19
1.5. Application of nursing theory on the present study.......................................................21
1.5.2. Application of Neuman’s model on the present study................................................22
Figure 1.1. Neuman theoretical model applied in the study.................................................24

CHAPTER 2. METHODOLOGY
.................................................................................................................................
25
2.1. Study design..................................................................................................................25
2.2. Subjects.........................................................................................................................25
2.2.1. Target population........................................................................................................25
2.2.2. Selected population....................................................................................................25
2.3. Sample size....................................................................................................................25
2.4. Sample collection..........................................................................................................25
2.5. Sampling criteria...........................................................................................................26
2.5.1. Inclusion criteria.........................................................................................................26
2.5.2. Exclusion criteria........................................................................................................26
2.5.3. Sampling procedure....................................................................................................26
Figure 2.2. Sampling procedure in the study........................................................................27
2.6. Data collection method..................................................................................................27
2.6.1. Data collection technique...........................................................................................27
2.6.2. Data collection tools...................................................................................................29
2.6.3. Data collectors............................................................................................................30
2.6.4. Methods of controlling systematic errors...................................................................30
2.7. Data analysis..................................................................................................................30
2.8. Definitions of variables.................................................................................................31
2.8.1. Demographic characteristics of patients.....................................................................31
2.8.2. Enviromental factors..................................................................................................32

2.8.3. Catheterization techniques of nurses..........................................................................33


2.8.5. Infectious condition of patients..................................................................................34
2.9. Medical Ethics...............................................................................................................35

CHAPTER 3. RESULTS
.................................................................................................................................
36
Table 3.3. The place where patients treated (n = 46)............................................................36
Table 3.4. Demographic profile of patients (n = 46)............................................................36

Age (years)
.................................................................................................................................
37
Table 3.5. History of morbidity of sample (n = 46)..............................................................38
Table 3.6. Environmental factors affect the risk of acquiring CAUTIs (n = 46)..................39
Table 3.7. Techniques of nurses before, during and after catheterization ( n = 46).............41
Table 3.8. Techniques of nurses for drainage system maintainace ( n = 46)........................42
Table 3.9. Urine culture and Gram-stain smear results........................................................43
after > 48h catheterization (n = 46)......................................................................................43
Table 3.10. The association between demographic characteristics and infectiuous condition of
patients (n = 46).........................................................................................................................44
Urinary tract infection..........................................................................................................44
(KTC 95%)...........................................................................................................................45
Yes........................................................................................................................................45

Age
.................................................................................................................................
45

Sex
.................................................................................................................................
45
Table 3.11. The association between infectious condition and history of morbidities of
patients (n = 46).........................................................................................................................46


Urinary tract infection..........................................................................................................46
(KTC 95%)...........................................................................................................................46
Yes........................................................................................................................................46

Diabetes mellitus
.................................................................................................................................
46
Kidney failure
.................................................................................................................................
46
Table 3.12. The association between environmental factors and infectious condition of
patients after > 48h catheterization (n = 46)..............................................................................48
Urinary tract infection..........................................................................................................48
(KTC 95%)...........................................................................................................................48
Yes........................................................................................................................................48

Place of catheter insertion
.................................................................................................................................
48
Reasons for catheterization
.................................................................................................................................
48
Urinary tract infection..........................................................................................................49

(KTC 95%)...........................................................................................................................49
Yes........................................................................................................................................49

Catheter sizes
.................................................................................................................................
49
Health condition of patients
.................................................................................................................................
49


Table 3.13. The associations between technique of nurses before, during and after
catheterization and infectious condition of patients (n = 46).....................................................50
Urinary tract infection..........................................................................................................50
(KTC 95%)...........................................................................................................................50
Yes........................................................................................................................................50
Table 3.14. The association between infectious condition and techniques of nurses for
maintainance of the drainage system (n = 46)...........................................................................52
Urinary tract infection..........................................................................................................52
(KTC 95%)...........................................................................................................................52
Yes........................................................................................................................................52

CHAPTER 4. DISCUSSION
.................................................................................................................................
53
REFERENCES
.................................................................................................................................
1
CONTENTS

Trang
ABBREVIATIONS
.................................................................................................................................
1
CAUTIs : Catheter-associated urinary tract infections
.................................................................................................................................
1
CDC : Centers for Disease Control and Prevention


.................................................................................................................................
1
CI : Confidence interval
.................................................................................................................................
1
ICU : Intensive care unit
.................................................................................................................................
1
PR : Prevalence ratio
.................................................................................................................................
1
UTI : Urinary tract infections
.................................................................................................................................
1
WHO : World Health Organization
.................................................................................................................................
1
LIST OF FIGURES AND TABLES
.................................................................................................................................
2

Trang
.................................................................................................................................
2
CONTENTS
.................................................................................................................................
8
Trang


.................................................................................................................................
8
INTRODUCTION
.................................................................................................................................
1
Objectives of the study...........................................................................................................3

CHAPTER 1. LITERATURE REVIEW
.................................................................................................................................
4
1.1. Nosocomial infections.....................................................................................................4
1.1.1. Definition of nosocomial infections.............................................................................4
Nosocomial infections are infections acquired during hospital care of patients. Infections
occurring more than 48 hours after admission are usually considered nosocomial infections.
Nosocomial infections could be classified into different categories in terms of infectious sites.
These are derived from those published by the Centers for Diseases Control and Prevention
(CDC) in the United States of America or during international conferences [28] and are used for
surveillance of nosocomial infections. Recently, about 50 types of nosocomial infections with
biological and clinical characteristics are identified....................................................................4
1.1.2. Epidemiology of nosocomial infections.......................................................................4
1.1.3. Types of nosocomial infection......................................................................................5

1.2. Urinary tract infection.....................................................................................................7
As mentioned above, UTIs are one of the most frequent nosocomial infections. According to
Craven, UTIs account for about 40% of all nosocomial infections in US hospitals each year [17].
UTIs often occur in ICU, outpatient or inpatient ward, and rehabilitation ward.........................7
The prevalence and mortality rate of UTIs vary among countries. In US, according to CDC
the prevalence of UTIs in 2002 was 17% of total cases of nosocomial infections; of these there
were 10% deaths, 5% cases developed bacteraemia. In European and Asian countries, the
incidence of UTIs fluctuated from 3.5 to 9.9% each year [45]....................................................7


Most of UTIs are associated with the utilization of an indwelling urinary catheter. In US,
there are 80% UTIs related to catheterization in patients with prolonged hospital stay [37]. In
2012, a review study investigated 4,109 studies worldwide showed that the attributable risk of
CAUTIs could be about 79.3% [35]. One study of Karina in Philippine found that the prevalence
of CAUTIs in a General Hospital raised up to 54.4% [34]. Mai Thi Tiet in her study in 2011
concluded that there were 26/41 patients (63.4%) acquired CAUTIs [8]....................................7
The prevalence of CAUTIs at ICU was highest, followed by internal medicine ward and
surgical ICU. CAUTIs do not only occur at hospital but at patient’s home after they are
discharged from hospitals. Beaver in his study in 2008 found that patients with indwelling
urinary catheter at home had the risk of acquiring CAUTIs between 2.1 and 6.7 days/1000 days
of catheterization [12]..................................................................................................................7
1.3. Catheter-associated urinary tract infection......................................................................8
1.3.1. Etiology........................................................................................................................8
1.3.2. Pathogenesis.................................................................................................................9
1.3.3. Clinical manifestations of CAUTIs..............................................................................9
1.3.5. Diagnosis of CAUTIs.................................................................................................11
1.4. Risk factors for CAUTIs...............................................................................................17
1.4.1. Demographic characteristics of patients.....................................................................17
1.4.2. Factors related to health condition of patients............................................................17
1.4.3. Factors related to patient’s illness..............................................................................17

1.4.4. Factors related to catheterization................................................................................18
1.4.5. Factors related to catheter characteristics...................................................................19
1.5. Application of nursing theory on the present study.......................................................21
1.5.2. Application of Neuman’s model on the present study................................................22
Figure 1.1. Neuman theoretical model applied in the study.................................................24

CHAPTER 2. METHODOLOGY
.................................................................................................................................
25
2.1. Study design..................................................................................................................25


2.2. Subjects.........................................................................................................................25
2.2.1. Target population........................................................................................................25
2.2.2. Selected population....................................................................................................25
2.3. Sample size....................................................................................................................25
2.4. Sample collection..........................................................................................................25
2.5. Sampling criteria...........................................................................................................26
2.5.1. Inclusion criteria.........................................................................................................26
2.5.2. Exclusion criteria........................................................................................................26
2.5.3. Sampling procedure....................................................................................................26
Figure 2.2. Sampling procedure in the study........................................................................27
2.6. Data collection method..................................................................................................27
2.6.1. Data collection technique...........................................................................................27
2.6.2. Data collection tools...................................................................................................29
2.6.3. Data collectors............................................................................................................30
2.6.4. Methods of controlling systematic errors...................................................................30
2.7. Data analysis..................................................................................................................30
2.8. Definitions of variables.................................................................................................31
2.8.1. Demographic characteristics of patients.....................................................................31

2.8.2. Enviromental factors..................................................................................................32
2.8.3. Catheterization techniques of nurses..........................................................................33
2.8.5. Infectious condition of patients..................................................................................34
2.9. Medical Ethics...............................................................................................................35

CHAPTER 3. RESULTS
.................................................................................................................................
36
Table 3.3. The place where patients treated (n = 46)............................................................36
Table 3.4. Demographic profile of patients (n = 46)............................................................36

Age (years)


.................................................................................................................................
37
Table 3.5. History of morbidity of sample (n = 46)..............................................................38
Table 3.6. Environmental factors affect the risk of acquiring CAUTIs (n = 46)..................39
Table 3.7. Techniques of nurses before, during and after catheterization ( n = 46).............41
Table 3.8. Techniques of nurses for drainage system maintainace ( n = 46)........................42
Table 3.9. Urine culture and Gram-stain smear results........................................................43
after > 48h catheterization (n = 46)......................................................................................43
Table 3.10. The association between demographic characteristics and infectiuous condition of
patients (n = 46).........................................................................................................................44
Urinary tract infection..........................................................................................................44
(KTC 95%)...........................................................................................................................45
Yes........................................................................................................................................45

Age
.................................................................................................................................

45
Sex
.................................................................................................................................
45
Table 3.11. The association between infectious condition and history of morbidities of
patients (n = 46).........................................................................................................................46
Urinary tract infection..........................................................................................................46
(KTC 95%)...........................................................................................................................46
Yes........................................................................................................................................46

Diabetes mellitus
.................................................................................................................................
46
Kidney failure


.................................................................................................................................
46
Table 3.12. The association between environmental factors and infectious condition of
patients after > 48h catheterization (n = 46)..............................................................................48
Urinary tract infection..........................................................................................................48
(KTC 95%)...........................................................................................................................48
Yes........................................................................................................................................48

Place of catheter insertion
.................................................................................................................................
48
Reasons for catheterization
.................................................................................................................................
48

Urinary tract infection..........................................................................................................49
(KTC 95%)...........................................................................................................................49
Yes........................................................................................................................................49

Catheter sizes
.................................................................................................................................
49
Health condition of patients
.................................................................................................................................
49
Table 3.13. The associations between technique of nurses before, during and after
catheterization and infectious condition of patients (n = 46).....................................................50
Urinary tract infection..........................................................................................................50
(KTC 95%)...........................................................................................................................50
Yes........................................................................................................................................50


Table 3.14. The association between infectious condition and techniques of nurses for
maintainance of the drainage system (n = 46)...........................................................................52
Urinary tract infection..........................................................................................................52
(KTC 95%)...........................................................................................................................52
Yes........................................................................................................................................52

CHAPTER 4. DISCUSSION
.................................................................................................................................
53
REFERENCES
.................................................................................................................................
1
REFERENCES

Appendix 1: The questionnaire
Appendix 2: List of patients
Appendix 3: The informed consent


1

INTRODUCTION

Nosocomial infection is one of the most challenging public health
problems in Vietnam and the world. It is resulted from infections acquired in
health facilities and is the cause increasing the length of hospitalization,
mortality, antibiotic resistance of bacteria and treatment cost for patients [5].
Urinary tract infections (UTIs) is the most common type of nosocomial
infection with high incidence, approximately 15–25% of all cases of nosocomial
infection; the standard guideline for prevention of UTI, however, is not available
[4]. It is estimated that 80% of UTIs in hospital settings are resulted from
prolonged indwelling urinary catheter [69]. Seven days after catheterization, the
rate of UTIs could be up to 91% [41]. A study conducted in 5 Japanese hospitals
in 2004 showed that the prevalence of UTIs in catheterized patients was 57%
[61]. A work of Nguyen Thi Tuyet Trinh found that the safe duration of
catheterization was about five days [10].. Some studies in Vietnam also
identified high prevalence of UTIs in several hospitals such as Dong Hoi
Vietnam-Cuba Friendship Hospital (22%) [3], Viet Duc Huu Nghi Hospital
(32.4%) [2], and Dong Nai General Hospital (14.8%) [9]. According to an initial
survey of Department of Infection Control at Nguyen Tri Phuong Hospital, the
prevalence of nosocomial infections in 2011 was 11.96%, of those UTIs
accounted for 12%.
Recent studies show that numerous factors could affect the development
of catheter-associated urinary tract infections (CAUTIs). They are patient’s

demographic characteristics such as older age, female, diabetes mellitus,


2

malnutrition, and cardiovascular diseases. Factors associated with catheter
insertion such as place of catheter insertion, duration of catheterization,
frequency of catheterization also play important roles in increasing the risk of
acquiring CAUTIs [13, 41]. Another crucial factor is catheterization technique of
health care workers. Non-sterile procedures applied before, during or after
catheter insertion can be responsible for high risk of developing CAUTIs [19].
Thus, identification of risk factors related to CAUTIs is a meaningful way to
prevent the development of CAUTIs and its complications.
Until now studies on risk factors related to CAUTIs in Vietnam are scarce.
Separately from the initial survey, there are not any studies on risk factors of
CAUTIs in Nguyen Tri Phuong Hospital. Hence, conducting a study to identify
the prevalence of CAUTIs and its risk factors is necessary so that the author can
make recommendations for improving the quality of catheterization care and
preventing patients form suffering complications of CAUTIs.


3

Objectives of the study
General objectives
Identify the prevalence of CAUTIs in patients with > 48 hours of
catheterization and the associations between CAUTIs and risk factors.
Specific objectives
1. Indentify the prevalence of CAUTIs in patients with > 48 hours of
catheterization in Nguyen Tri Phuong Hospital.

2. Indentify the associations between CAUTIs and demographic characteristics
of patients, environmental factors of catherization, and catheterization techniques
of nurses in Nguyen Tri Phuong Hospital.


4

CHAPTER 1. LITERATURE REVIEW

1.1. Nosocomial infections
1.1.1. Definition of nosocomial infections
Nosocomial infections are infections acquired during hospital care of
patients. Infections occurring more than 48 hours after admission are usually
considered nosocomial infections. Nosocomial infections could be classified into
different categories in terms of infectious sites. These are derived from those
published by the Centers for Diseases Control and Prevention (CDC) in the
United States of America or during international conferences [28] and are used
for surveillance of nosocomial infections. Recently, about 50 types of
nosocomial infections with biological and clinical characteristics are identified.
1.1.2. Epidemiology of nosocomial infections
In 2002, a report of WHO showed that there were 8.7% of hospitalized
patients in 14 countries acquired nosocomial infections [70]. According to the
report, hospitals from countries of East Mediterranean and Southeast Asia had
the most cases of nosocomial infections (11,8% and 10%, respectively), followed
by West Pacific and Europe (7,7% and 9%, respectively).
The most common types of nosocomial infections are surgical site
infections, UTIs, nosocomial pneumonia, and nosocomial bacteraemia. Mai Thi
Tiet carried out a survey at Dong Nai General Hospital in 2011 and found that
the prevalence of nosocomial infections was 5.1%, of those pneumonia was
highest (43.9%), followed by UTIs, skin and soft tissue infections, and surgical

site infections (12.2%, 12.2% and 4.5%, respectively) [9]. A study of Doan


5

Phuoc Thuoc conducted in Binh Dinh General Hospital revealed that the
prevalence of nosocomial infections was 4.8%, of which pneumonia accounted
for 20.6%, bacteraemia 14.7%, surgical site infections 29.5%, and skin and soft
tissue infections 23.5% [7].
According to WHO, the sites where had most cases of nosocomial
infections were intensive care units (ICU), operation room, and orthopedic ward
[70]. Doan Phuoc Thuoc reported that internal ICU and surgical ICU had the
highest prevalence of nosocomial infections (42.9% and 18.8%, respectively)
[7].
1.1.3. Types of nosocomial infection
As previously mentioned, nosocomial infections could be classified in
terms of infectious sites. There are four common types of nosocomial infections
including UTIs, surgical site infections, nosocomial pneumonia, and nosocomial
bacteraemia.
Urinary tract infections
This is the most common nosocomial infections. An Irish study in 2006
showed that UTIs accounted for 22.5% of total cases of nosocomial infections
[52]. A large study of 14.672 patients in 13 European nations revealed that the
prevalence of UTIs was 30% of total nosocomial infections [31]. UTIs may not
cause acute symptoms compared with other types but it may lead to mortality
sometimes. Patient with UTIs were defined as patients who had a positive urine
culture (> 105 CFU/ml of urine) with no more than two species of
microorganisms.

6

Surgical site infections
Surgical site infections are also frequent: the incidence varies from 0.5 to
15% depending on the type of operation and underlying patient status [20].
These are significant problems which limit the potential benefits of surgical
interventions. The impact on hospital costs and postoperative length of stay
(between 3 and 20 additional days) is considerable. [50].
Nosocomial pneumonia
Nosocomial pneumonia occurs in several different patient groups. The
most important groups are patients on ventilators in ICU. There is a high casefatality rate associated with ventilator-associated pneumonia, although the
attributable risk is difficult to determine because patient’s comorbidity is so high.
One study conducted in Bach Mai Hospital between 2008 and 2009 to
investigate the prevalence of nosocomial pneumonia reported that 90/477
(18.9%) patients acquired pneumonia. Compared with noninfected group, the
infected group had longer length of hospital stay (28.2 ± 18.7 vs 13.5 ± 11.4; p<
0.01), higher mortality rate (55.6% vs 30.0%; p < 0,01) and higher treatment cost
(79.4 ± 57.2 million dong vs 26.0 ± 23.9 million dong; p < 0.01) [6].
Nosocomial bacteraemia
These infections represent a small proportion of nosocomial infections
(approximately 5%) but case-fatality rates are high - more than 50% for some
microorganisms. The incidence is increasing, particularly for certain organisms
such as multiresistant coagulase-negative Staphylococcus and Candida spp.
Infections may occur at the skin entry site of the intravascular device, or in the
subcutaneous path of the catheter. Organisms colonizing in the catheter may
produce bacteraemia without visible external infection. The main risk factors are


7

the length of catheterization, level of asepsis at insertion, and continuing catheter
care.
1.2. Urinary tract infection
As mentioned above, UTIs are one of the most frequent nosocomial
infections. According to Craven, UTIs account for about 40% of all nosocomial
infections in US hospitals each year [17]. UTIs often occur in ICU, outpatient or
inpatient ward, and rehabilitation ward.
The prevalence and mortality rate of UTIs vary among countries. In US,
according to CDC the prevalence of UTIs in 2002 was 17% of total cases of
nosocomial infections; of these there were 10% deaths, 5% cases developed
bacteraemia. In European and Asian countries, the incidence of UTIs fluctuated
from 3.5 to 9.9% each year [45].
Most of UTIs are associated with the utilization of an indwelling urinary
catheter. In US, there are 80% UTIs related to catheterization in patients with
prolonged hospital stay [37]. In 2012, a review study investigated 4,109 studies
worldwide showed that the attributable risk of CAUTIs could be about 79.3%
[35]. One study of Karina in Philippine found that the prevalence of CAUTIs in a
General Hospital raised up to 54.4% [34]. Mai Thi Tiet in her study in 2011
concluded that there were 26/41 patients (63.4%) acquired CAUTIs [8].
The prevalence of CAUTIs at ICU was highest, followed by internal
medicine ward and surgical ICU. CAUTIs do not only occur at hospital but at
patient’s home after they are discharged from hospitals. Beaver in his study in
2008 found that patients with indwelling urinary catheter at home had the risk of
acquiring CAUTIs between 2.1 and 6.7 days/1000 days of catheterization [12].


8

CAUTIs tend to occur in lower urinary tract that is already colonized with
bacteria, especially when the catheter remains indwelling for a period of days to

weeks. Patients with an indwelling catheter develop bacteriuria at a rate of 3% 10% per day and the incidence approaches 100% within the first 30 days
following catheter insertion [37, 38].
1.3. Catheter-associated urinary tract infection
1.3.1. Etiology
Most of agents caused CAUTIs have been identified in numerous studies
worldwide. The agents could be classified into two groups: commensal and
pathogenic bacteria.
Commensal bacteria are microorganisms that exist in human body and for
some reasons get involved in catheter insertion, colonize in urinary tract and
cause infection. These bacteria include most of Enterobacteria such as E. Coli
(account for 20-30% of CAUTIs) [29, 34], Klebsiella pneumoniae (7-25%) [34],
and Enterobacteria. spp (4-10%) [34, 51].
Pathogenic bacteria are microorganisms that followed infected equipment
or nonsterile hands of health care providers or unsterilized environment to invade
urinary tract and cause infection. Some of these are Pseudomonas aeruginosa
(account for 6-10% of CAUTIs) [34], Serratia marcescene, Proteus. spp… [34].
Candida spp in some cases are also the agent predisposing to CAUTIs. From 10
to 25% of CAUTIs were caused by Candida. spp according to several studies
[34].


9

1.3.2. Pathogenesis
Commensal bacteria
Commensal bacteria usually exist in patients’ stools. As health care
workers perform unsterilized catheterization or do not clean the genital area
during catheter insertion, these agents from patients’ anus move to urinary
meatus and cause CAUTIs [54].
Pathogenic bacteria

The bacteria can exist in catheter equipments or infected hands of health
care workers. When a catheter is inserted into urethra of patients with prolonged
hospital stay, the urethra mucosa is stimulated and releases fluids that are the
reservoir for biofilm establishment [27, 43]. The bacteria will colonize and
develop in catheter and drainage system that in turn leads to CAUTIs.
Moreover, the bacteria can invade into urethra of patients from unclosed
drainage system. Obstructed drainage system is also one of factors that leads to
CAUTIs [38]. Recent studies showed that cross-sectional infection from patients
to patients also increases the risk of CAUTIs in prolonged hospitalized patients.
1.3.3. Clinical manifestations of CAUTIs
Less

than

one-quarter

of

hospitalized

patients

with

short-term

catheterization develop symptoms of UTIs [48, 56]. In one study of 235 new
cases of nosocomial urinary infection, > 90% of infected patients were
asymptomatic and afebrile [56]. Likewise, in a retrospective cohort study
describing 510 consecutive patients with trauma, neither fever nor leukocytosis

was associated with CAUTIs [22].
Most of patients with CAUTIs (> 70%) were asymptomatic cases. For
symptomatic patients, clinical manifestations may be: fever (increase in body


10

temperature > 20F or 1.10C), abdominal or suprapubic tenderness, change in
urine features, hematuria, sudden changes in mental or functional status [16].
1.3.4. Complications of CAUTIs
The effect of CAUTIs on mortality remains controversial. Platt et al
reported in a prospective study involving 1,458 hospitalized patients with
indwelling bladder catheterizations that death rates were 19% among patients
with CAUTIs, compared with 4% among those without, with an adjusted odds
ratio for mortality between those who acquired CAUTIs and those who did not
of 2.8 (95% confidence interval [CI], 1.5–5.1) [47]. The mechanism accounting
for an increased mortality among catheterized patients would presumably be
secondary bacteremia and septicemia but this is only speculative. Other
investigators, in studies of mostly patients hospitalized in the ICU, have not
shown an increased mortality risk associated with CAUTIs [55, 62]. The
association with mortality is likely explained by confounding, because
catheterized patients tend to be sicker and more functionally impaired.
Studies performed almost 3 decades ago demonstrated that patients who
develop CAUTIs have their hospital stays extended by 2–4 days [21, 25]. Haley
et al [26] estimated that the attributable additional length of stay was somewhat
shorter, ranging from 0.4 days for asymptomatic CAUTIs to 2.0 days for
CAUTIs. In recent studies conducted in the era of managed care, each episode of
asymptomatic CAUTIs and CAUTIs has been estimated to cost an additional
$589 and $676, respectively, and bacteremia associated with CAUTIs is
estimated to cost at least $2,836 [57]. The high frequency of catheter use means

that these infections may add as much as $500 million to health care costs in the
US each year. However, episodes of asymptomatic CAUTIs that are not detected