الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The use of DJ stents has become an essential routine 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 addition to early complications like suprapubic pain,
hematuria, the frequent need to urinate and burning during urination, more serious late
complications like stent migration, stent fragmentation, encrustation, vesicoureteral reflux,
acute pyelonephritis, bacteremia and chronic renal failure may develop. Bacterial
colonization 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 leading to
death.
This pre-post intervention study aimed to isolate and identify the causative agents
responsible for UTI and stent colonization following ureteroscopic stent insertion; as well
as to determine the antimicrobial susceptibility pattern of the isolates and to monitor the
infection control measures implemented during the ureteroscopic stent insertion at the
urology unit at Alzahraa hospital in Desoq in Kafr El Sheikh.
The study involved 100 patients who were admitted to the urology unit in Alzahraa
hospital in Desoq in Kafr El Sheikh for ureteroscopy.
A total of 300 samples including 200 urine samples and 100 stent samples were
collected. Clean catch mid-stream urine samples (89 before insertion and 100 on the day of
stent removal) as well as eleven urine samples were collected from catheterized patients in
sterile disposable screw capped containers.
After stent removal, about 3 to 5 cm of the tip of the stent was cut off aseptically and
placed in a sterile screw capped test tube.
All urine samples were subjected to complete urine analysis which included physical
examination (volume, aspect, odor and color), chemical examination (using Medi-Test
Combi 10 reagents dipstick) and microscopic examination.
Semi-quantitative urine culture procedure was done on the surface of a well dried
blood, CLED, MacConkeyʼs and SDA agar plates using a standard calibrated loop which
was inserted vertically into the well mixed urine samples. All the inoculated plates were
incubated aerobically at 37oC for 24 hours while SDA plates were incubated at 27oC for 48
hours and up to 10 days. Colonies were counted using Quebec colony counter.
All stents were vortexed in one ml peptone water, then 100 μl aliquots were inoculated and
streaked using a standard calibrated 10 micron loop over the surface of each of blood,
MacConkeyʼs, CLED and SDA agar plates. Blood, CLED and MacConkeyʼs agar plates were
incubated at 37oC for 24 hours aerobically, while SDA agar plates were incubated at 27oC for 48
hours and up to 10 days. Colonies were counted using Quebec colony counter.
All isolated bacterial and fungal agents were examined morphologically and further
identified by biochemical reactions according to the methods described by Tille and some
isolates were confirmed using Vitek 2 compact system at Alexandria Main University
Hospital.
Summary and Conclusions
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All bacterial isolates were subjected to antimicrobial susceptibility testing using disc
diffusion method described by Bauer and Kirby on Mueller Hinton agar plates. Inhibition
zones were measured, recorded and interpreted according to the CLSI tables.
The results of this study can be summarized as follow:
1- Of the 100 examined patients, 12.0% had positive urine cultures before stent
insertion, while on the day of stent removal positive urine cultures increased
to 43.0%.
2- Positive DJ stent cultures were detected in 68.0% of patients on the day of removal.
3- There was a moderate agreement (76.0%) between pyuria and urine culture, where of
the 85 patients with pyuria, 46 (54.1%) revealed positive urine cultures.
4- Of the examined 100 stents, 43.0% of stents had monomicrobial colonization, 25.0%
had polymicrobial colonization.
5- All of the 14 stents (100.0%) which were inserted for duration of more than 30 days
were colonized, while only 62.8% that were inserted for less than 30 days showed
colonization.
6- All of the 14 patients (100.0%) who had stents inserted for more than 30 days had
positive urine cultures on the day of stent removal, while only 33,7% of patients who
had stent for less 30 days showed positive urine cultures on the day of stent removal.
7- There was a moderate agreement between urine cultures on the day of stent removal
and DJ stent culture results which was statistically significant. (P value ˂0.001).
8- A slight agreement was detected between urine culture results before and after
stenting. These results were statistically significant (P value ˂0.001).
9- Candida spp. was the most frequently isolated organism from urine samples before
stent insertion and on the day of stent removal in addition to stent cultures (29.4%,
31.3%, and 25.8%, respectively).
10- E.faecalis was the most commonly encountered bacterial agent form urine cultures
on the day of stent removal and from stent samples (22.4% and 23.7%, respectively),
while P.aeruginosa followed Candida spp. in urine samples before stent insertion
(23.5%).
11- P.aeruginosa isolates from urine samples before stent insertion showed the highest
susceptibility percentages to colistin and polymyxin B (75.0%) each, followed by
ceftazidime (50.0%), while the lowest percentages were recorded for ciprofloxacin,
amikacin, imipenem and piperacillin-tazobactam (25.0%) each, on the other hand all
five isolates on the day of the stents removal and the six isolates from stents were
susceptible to polymyxin B and colistin 100.0%, respectively.
12- The highest percentage of sensitivity (100.0%) for E.coli before stent insertion was
recorded for piperacillin-tazobactam, amikacin, imipenem and nitrofurantoin, while for
isolates recovered from the stent, piperacillin-tazobactam was the highest one (76.9%).
13- K.pneumoniae isolates from urine before stent insertion was 100.0% sensitive to
imipenem, while for isolates recovered from the stents, this percentage decreased to
83.3%. and
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14- E.faecalis isolates from urine before stent insertion were 100.0% susceptible to
teicoplanin and vancomycin, while isolates recovered from stents were highly
susceptible to linezolid and teicoplanin (81.8%) each.
15- A.lwoffii isolate before stent insertion was sensitive to piperacillin-tazobactam,
imipenem, amikacin and ciprofloxacin. Isolate recovered from stent was sensitive to
piperacillin-tazobactam, imipenem and ciprofloxacin only.
16- Among infection control measures, keeping nail tips short, wearing sterile disposable
gloves, performing leak test and proper linen and waste management significantly
affected the colonization rate.
It can be concluded from this study that:
1. There was a significant relationship between stent colonization and duration of
ureteral stenting.
2. There was a significant relationship between positive urine culture on the day of stent
removal and duration of ureteral stenting.
3. Candida spp. were the most commonly isolated microorganism from all studied
samples.
4. E.faecalis isolates were the most frequently isolated bacteria from stent samples and
from urine samples on the day of stent removal.
5. The majority of bacterial isolates recovered from stents showed higher resistance to
antibiotic than isolates recovered from urine before stent insertion.
6. Stent colonization is not usually associated with bacteriuria, thus a negative culture
does not rule out a colonized stent.
7. There was a significant relationship between compliance with infection control
measures and rates of stents colonization.