Stesura Seveso


291Archivio Italiano di Urologia e Andrologia 2015; 87, 4

ORIGINAL PAPER

Incidence of bacterial colonisation after indwelling 
of double-J ureteral stent

Hasan Riza Aydin 1, Lokman Irkilata 2, Mustafa Aydin 2, Selim Gorgun 3, Hüseyin Cihan Demirel 2,
Senol Adanur 4, Mevlüt Keleş 2, Aynur Atilla 5, Mustafa Kemal Atilla 5

1 Department of Urology, Recep Tayyip Erdoǧan University, Rize, Turkey; 
2 Department of Urology, Samsun Training and Research Hospital, Samsun, Turkey;
3 Department of Microbiology, Samsun Training and Research Hospital, Samsun, Turkey;
4 Department of Urology, Ataturk University, Erzurum, Turkey;
5 Department of Infectious Diseases, Samsun Training and Research Hospital, Samsun, Turkey.

Objective: To determine the bacterial
colonisation after double-J stent use and

the risk factors for bacteriuria linked to the stent.
Materials and Methods: A total of 102 patients (61 men and
41 women, mean age 47.5 ± 14.16) were examined. The
stents were removed under aseptic conditions, and a urine
culture was obtained before the removal of the stents. After
the stents were removed, the upper, central and lower sec-
tions were separated, and washing water was sent through
the stent.
Results: Bacterial colonisation was found in 29.4% (30 of
102) of the stents. The most frequently observed microorgan-
isms were determined as staphylococcus, coagulase negative
(8 of 30) and E. coli (5 of 30). The washing fluid used to
clean the interior of the catheter produced pathogens in 8
patients (7.8%), and these pathogens were observed to be the
same microorganisms that colonised the outside of the stent.
There was no statistical difference between the patients with
colonisation and those without in terms of age, gender, dura-
tion of stenting and reason for stent insertion.
Conclusions: Though stent colonisation does not always entail
symptomatic urinary tract infections, as shown in our study,
the pathogens in the urine culture are the same as those
colonising the stent, confirming the reality that colonisation is
the main factor in these events. Additionally, according to our
study, significant colonisation may be found in the first 3
weeks, contrary to the literature, causing us to consider that
urinary tract infections may develop even in the early period.

KEY WORDS: Bacterial adhesion; Risk factors; Ureteral 
catheterization; Urinary tract infection.

Submitted 22 July 2015; Accepted 13 October 2015

Summary

No conflict of interest declared.

of double-J stents, early intolerance and a variety of late
complications are present (4). Eighty percent of nosocomi-
al urinary tract infections are linked to urological instru-
mentation, especially the use of the double-J stent (5). The
increase in the use of the stent is related to stent-linked
infections, and bacterial stent colonisation plays an impor-
tant role in infections linked to the stent (6, 7). In this
study, we aimed to determine the bacterial colonisation
after double-J stent use and the risk factors for bacteriuria
linked to the stent.

MATERIALS AND METHODS
The study prospectively included 102 patients with dou-
ble-J stentsused from July through December 2014 for a
variety of reasons. The patients gave written consent to
participate. Double-j stents are generally produced from
polyurethane. Patients using antibiotics for any reason,
patients with immunosuppression and those with bacte-
ria in urine cultures were excluded from the study. All
patients were given a single dose of antibiotic (iv 1 g
cephalozin) before the procedure. The stents were
removed under aseptic conditions, and a urine culture
was obtained before the stents were removed. After the
stents were removed, the upper, central and lower sec-
tions were separated, and washing water was sent
through the stent. The suspension to wash the inner sur-
face was normal saline jetted through a 10 ml 21-gauge
needle syringe into the inner portion of the stent seg-
ment. All samples were inoculated on eosin methylene
blue agar and blood agar. Positive cultures were defined
as the growth of > 105 colony-forming units (cfu)/ml of
a single pathogen. IBM SPSS for Windows, version 21.0
(Chicago, USA) was used for statistical analysis. Data
were calculated as mean ± standard deviation. The Chi-
square, Pearson Chi-square and Fisher’s Exact tests were
used, and p < 0.05 was accepted as significant.

RESULTS
A total of 102 double-J stents from 102 patients were
taken for assessment. The mean age of patients was 47.5

DOI: 10.4081/aiua.2015.4.291

INTRODUCTION
In urology practice, the use of the double-J stent had sig-
nificantly influenced endourologic developments and
techniques. The double-J stent is used in a very broad
area, including treatments for ureter and kidney stones,
hydronephrosis linked to pregnancy or oncological dis-
eases, cleaning fragments after shock wave lithotripsy
and treatment of urinary leaks (1-3).
In spite of increasing experience linked to the frequent use



Archivio Italiano di Urologia e Andrologia 2015; 87, 4

H. Riza Aydin, L. Irkilata, M. Aydin, S. Gorgun, H. Cihan Demirel, S. Adanur, M. Keleş, A. Atilla, M. Kemal Atilla

292

± 14.16 years, with 61 male (59.8%) and 41 female
(40.2%) patients. The mean duration of stent insertion
was 33.91 ± 22.42 days. The indications for stent inser-
tion were urinary system stone disease in 86 patients
(84.4%), ureteral stenosis in 7 patients (6.9%), malig-
nancy in 6 patients (5.9%), hydronephrosis linked to
pregnancy in 2 patients (2%) and UPJ stenosis in 1
patient (1%).
Bacterial colonisation of the stent was observed in a total
of 30 patients (29.4%). The most frequently observed
microorganisms were determined as staphylococcus,
coagulase negative and E. coli (Table 1). In patients with
proliferation, the same pathogen was found to colonise
all 3 catheter fragments. The washing fluid used to clean
the interior of the catheter produced pathogens in 8

patients (7.8%), and these pathogens were observed to
be the same microorganisms that colonised the outside
of the stent.
The urine culture sampling on the same day as the stent
was removed found proliferation in 4 (13.3%) of the 30
patients with colonisation. These pathogens were the
same as those colonising the stent, with one patient hav-
ing MRSA staph aureus and the other 3 having E. coli.
Twenty-six patients (86.7%) had a sterile urine culture.
Colonisation was found in 19 (31.1%) of the 61 male
patients and in 11 (26.8%) of the 41 female patients.
There was no statistical difference between the patients
with colonisation and those without in terms of age, gen-
der, duration of stent and reason for stent insertion
(Table 2).

DISCUSSION
The use of double-J stents has become an essential rou-
tine in urology practice. While the first studies reported
minimal complications linked to stents, the increased
frequency of the use of stents has revealed that, in addi-
tion to early complications like suprapubic pain, hema-
turia, the frequent need to urinate and burning during
urination, more serious late complications like stent
migration, stent fragmentation, encrustation, vesi-
coureteral reflux, acute pyelonephritis, bacteriemia and
chronic renal failure may develop (8-10). Bacterial
colonisation on the stent plays the main role in infections
linked to the stent, though as these infections may follow
a subclinical progression, they may result in sepsis lead-
ing to death (11). 
A biofilm layer formed by protein, electrolytes and an
unknown variety of molecules causing bacterial adhesion
and deposition on the stent is responsible for the first
stage of these events (12).
The literature presents a variety of rates related to bacte-
rial stent colonisation. Riedl et al. reported rates of 100%
in permanent stents and 69% for temporary stents (13).
Similarly, in another study, this rate was given as 68%
(14). When other studies are examined, Paick et al. pub-
lished 44%, Akay et al. reported 31% proximal and 34%
distal, and Özgür et al. reported bacteria colonisation of
10% (15-17). In our study, the rate was the samefor each
piece of the stent (proximal, central and distal) at 29.4%.
The differences between these rates may be linked to the
type of stent, duration of insertion and use of antibiotics.
When the bacteriuria rates are examined in these studies,
they vary from 21-45% with the general view that, just
as every stent colonisation will not cause bacteriuria,
every negative urine culture does not mean that there is
no stent colonisation. 
In our study, in the 30 patients with stent colonisation,
the fact that only 4 (13.3%) had bacteriuria supports this
opinion. Additionally, as the pathogen found in urine
samples from these 4 patients was the same pathogen
that colonised their stents, the reality that the main cause
of urinary tract infection is stent colonisation should not
be forgotten.
A variety of risk factors for bacteria colonisation have
been researched. Kehinde et al. mentioned that the risk
increased 2 times for women (18). Similarly, Atay et al.

Microorganism N %

Sterile 72 70.6

Staphylococcus, coagulase negative 8 7.8

E. coli 5 4.9

Candida 4 3.9

Group B Streptococcus 3 2.9

Staphylococcus epidermidis 2 1.96

Diphtheroid 2 1.96

Staph Aureus (MRSA) 2 1.96

Enterobacter 2 1.96

Enterococcus 1 0.98

Acinetobacter baumoni 1 0.98

Colonisation
Groups Present Absent Total P
Gender

Male 19 42 61 0.639
Female 11 30 41

Total 30 72 102
Age

20-29 7 12 19 0.367
30-39 7 11 18
40 and ↑ 16 49 65

Total 30 72 102
Stent duration

1-21 9 22 31 0.974
22-42 15 37 52
43 and ↑ 6 13 19

Total 30 72 102
Reason for insertion

Stone 26 60 86 0.773
Other 4 12 16

Total 30 72 102

Table 1. 
Pathogens colonizing the stent.

Table 2. 
Comparison of patients with and without colonisation in
terms of age, gender, stent duration and reason for
insertion.



found higher rates of colonisation in women (16). In our
study,colonisation was found in 31.1% of men and
26.8% of women, with the difference not significant.
When the duration of stent use is assessed, 
Farsi et al. stated that, as the stent duration increased, the
colonisation rates increased (before 1 month 58.6%,
after 3 months 75.1%) (14). Similarly, Kehinde et al. stat-
ed that, as the duration lengthened, the risk of bacteri-
uria and colonisation increased (1st month 4.2%, 3rd

month 34%) (18). Özgür et al. grouped patients accord-
ing to stent duration as less than 4 weeks, 4-6 weeks and
more than 6 weeks and found a significantly increased
risk of colonisation after 6 weeks (17). 
Paick emphasised that colonisation began after 2 weeks
and that antibiotic use for stents that would be removed
before this duration was unnecessary (15). In our study,
we divided patients according to stent durations as 1-21
days, 22-42 days and more than 43 days. Though the
colonisation rates were higher for those with stents
inserted for 43 days or more, the difference was not sta-
tistically significant similar to Akay’s study. However,
when it is considered that the stents will remain in the
majority of patients for around 4 weeks, the longer dura-
tion will likely increase the risk of colonisation.
In our study, 9 patients had hypertension, and 2 patients
were pregnant. As immunosuppressive and diabetic
patients were excluded from the study, we did not assess
the effect of comorbidities on colonisation. However, as
previous studies have shown, because situations such as
chronic renal failure (CRF), diabetes mellitus (DM) and
pregnancy weaken the immune system, it is possible to
mention an increased colonisation risk in these patients
(16, 18). Rates of urinary system infections may increase
due to situations linked to age such as bladder outlet
obstruction, hormonal changes and changes in bladder
connective tissue (19). 
In our study, when the patients were divided according
to age groups like 20-29, 30-39 and 40 years and above,
there was no significant difference determined in terms
of colonisation. Additionally, when colonisation rates are
examined according to reason for stent insertion, com-
paring urinary system stone disease and other reasons, it
was found there was no effect from reason for insertion
on colonisation.

CONCLUSIONS
Double-J stents are a frequently used, essential tool of
urological instrumentation and are one of the leading
choices for temporary urinary diversion. Additionally, it
should not be forgotten that there is a range of early and
late complications due to stents. One of the most impor-
tant of these complications is urinary system infection.
Though stent colonisation does not always entail symp-
tomatic urinary tract infections, as shown in our study,
the pathogens in the urine culture are the same as those
colonising the stent, confirming the reality that colonisa-
tion is the main factor in these events. Moreover, accord-
ing to our study, significant colonisation may be found in
the first three weeks, contrary to the literature, causing
us to consider that urinary tract infections may develop
even in the early period. As a result, the indications for

stent insertion should be carefully considered, the dura-
tion of the stenting period should be especially opti-
mised, appropriate antibiotic prophylaxis should be
organised, and the treatment of patients with risky
comorbidities should be well-planned. 
In our study, though there was no effect of stent dura-
tion, age, gender and reason for insertion on colonisa-
tion, lengthened stent durations may especially increase
the risk of bacterial colonisation and bacteriuria, and it
should be remembered that those with diseases like
chronic renal failure (CRF) and diabetes mellitus (DM)
may be at risk.

FINANCIAL SUPPORT
We took support from Samsun Training and Research
Hospital’s Training and Research Foundation for microbio-
logical evaluation in this study. 
We want thank to Naci Murat who performed the statis-
tical analyzes of our study. 

REFERENCES
1. Lang EK, Lanasa JA, Garrett J, Stripling J, Palomar J. The man-
agement of urinary fistulas and strictures with percutaneous ureter-
al stent catheters. J Urol. 1979; 122:736.

2. Laverson PL, Hankins GD, Quirk JG. Ureteral obstruction dur-
ing pregnancy. J Urol. 1984; 131:327.

3. Ball AJ, Gingell JC, Carter SS, Smith PJ. The indwelling ureteric
splint: the Bristol experience. Br J Urol. 1983; 55:622.

4. Saltzman B. Ureteral stents: indications, variations, and compli-
cations. Urol Clin North Am. 1988; 15:481.

5. Paz A, Amiel GE, Pick N, et al. Febrile complications following
insertion of 100 double-J ureteral stents. J Endourol. 2005; 19:147.

6. Reid G, Sobel JD. Bacterial adherence in the pathogenesis of uri-
nary tract infection: a review. Rev Infect Dis. 1987; 9:470.

7. Costerton JW, Cheng KJ, Geesey GG, et al. Bacterial biofilm in
nature and disease. Ann Rev Microbiol. 1987; 41:435.

8. Stamm WE. Guidelines for prevention of catheter associated uri-
nary tract infections. Ann Intern Med. 1975; 82:386.

9. Warren JW, Muncie HL Jr., Hall-Craggs M. Acute pyelonephritis
associated with bacteriuria during long-term catheterization: a
prospective clinicopathological study. J Infect Dis. 1988; 158:1341.

10. Vallejo Herrador J, Burgos Revilla FJ, Alvarez Alba J et al.
Double J ureteral catheter. Clinical complications. Arch Esp Urol.
1988; 51:361.

11. Warren JW, Damron D, Tenney H, et al. Fever, bacteremia, and
death as complications of bacteriuria in women with long-term ure-
thral catheters. J Infect Dis. 1987; 155:1151.

12. Habash M, Ried G. Microbial biofilms: their development and
significance for medical device-related infections. J Clin Pharmacol.
1999; 39:887.

13. Riedl CR, Plas E, Hubner WA, et al. Bacterial colonisation of
ureteral stents. Eur Urol. 1999; 36:53.

14. Farsi HM, Mosli HA, Al-Zemaity MF, et al. Bacteriuria and
colonisation of double-pigtail ureteral stents: long-term experience
with 237 patients. J Endourol. 1995; 9:469.

293Archivio Italiano di Urologia e Andrologia 2015; 87, 4

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294

15. Paick SH, Park HK, Oh SJ, Kim HH. Characteristics of bacter-
ial colonisation and urinary tract infection after indwelling of dou-
ble-J ureteral stent. Urology. 2003; 62:214.

16. Akay AF, Aflay U, Gedik A, et al. Risk factors for lower urinary
tract infection and bacterial stent colonisation in patients with a
double J ureteral stent. Int Urol Nephrol. 2007; 39:95.

17. Ozgur BC, Ekıcı M, Nedım Yuceturk C, Bayrak O. Bacterial

colonisation of double J stents and bacteriuria frequency. Kaoh J Med
Sci. 2013; 29:658.

18. Kehinde EO, Rotimi VO, Al-Awadi KA, et al. Factors predispos-
ing to urinary tract infection after J ureteral stent insertion. J Urol.
2002; 167:1334.

19. Beyer I, Mergam A, Benoit F, et al. Management of urinary tract
infections in the elderly. Z Gerontol Geriatr. 2001; 34:153.

Correspondence

Hasan Riza Aydin, MD
hrizaaydin@gmail.com

Recep Tayyip Erdoğan University, Department of Urology, Rize, Turkey

Lokman Irkilata, MD (Corresponding Author)
irkilatamd@gmail.com

Samsun Training and Research Hospital, Department of Urology
Kadıköy Mahallesi, Altın Barıs Bulvarı No:199, Ilkadım/Samsun, Turkey

Mustafa Aydin, MD
mustafaydin28@gmail.com

Selim Gorgun, MD
compass71@mynet.com

Hüseyin Cihan Demirel, MD
drhcdemirel@gmail.com

Mevlüt Keleş, MD
drmevlutkeles@gmail.com

Mustafa Kemal Atilla, MD Ass. Prof
mkatilla@hotmail.com

Samsun Training and Research Hospital, Department of Urology, Samsun, Turkey

Senol Adanur, MD
s.adanur61@hotmail.com

Ataturk University, Department of Urology, Erzurum, Turkey 

Aynur Atilla, MD
aynur.atilla@gmail.com

Samsun Training and Research Hospital, Department of Infectious Diseases, Samsun, Turkey