1. Urinary Tract Infections in intensive care
Chatterjee SS, Taneja N. Meenakshi S, Sharma M.
Department of Medical Microbiology, PGIMER, Chandigarh

2. Introduction
Few studies have evaluated urinary tract infections (UTIs) specifically in patients admitted to intensive care units.1
ICU associated UTIs have been associated with increased length of hospital stay and cost, if not with increased mortality.1,4,5,6
Incidence varies in literature, being higher in developing nations and lower in developed countries, as does the proportion of antibiotic resistant organisms causing UTI.7
The National Nosocomial Infection Surveillence System (NNIS, USA) reports UTI as the commonest ICU infection, being responsible for 20-30% of all infections in these settings.2,3

3. Urinary catheterization is the most important predisposing factor to complicated UTIs and most ICU patients are catheterized during some part of their stay.
Literature suggests that ICU associated UTIs are independently associated with length of hospital stay, length of catheterization, age more than 60 years and female gender.
Difference in rates of UTI has been demonstrated in patients admitted to medical, surgical and cardiac surgical ICUs. Incidence of UTIs is low in pediatric critical care units, and almost nil in neonatal ICUs.

4. UTI in intensive care patients are under routine surveillance in industrialized western countries.
However, very few studies have looked into UTI acquisition in ICUs of developing countries, especially, there are no published studies from India.
Keeping this in view, we analyzed two year data from ICU patients in our tertiary care center to know the prevalent microorganisms and their antimicrobial susceptibility pattern.

5. Material and Methods
A two year retrospective analysis was done (January 2005 to December 2006). All urine samples from seven ICUs were included.
At our center quantitative unspun wet mount microscopy and semiquantitative culture is done for all samples received.
Significant pyuria was defined as more than one pus cell in 7 high power fields and significant bacteriuria was said to be present when > 1 bacteria were present in 3 high power fields.
105 cfu/ml is taken as a threshold for culture positivity.
Isolates were identified by gram stain, motility test and routine biochemical reactions.

6. Antibiotic sensitivity is put up by the Kirby Bauer method following the CLSI guidelines13.
All Enterobacteriaceae and Acinetobacter spp.were tested against first line agents: Gentamicin, Amikacin, Cefoperazone, Ceftazidime, Nitrofurantoin, Trimethoprim-Sulfamethoxazole, Nalidixic acid, Norfoxacin and Ciprofloxacin; Enterococcus spp. against Amoxycillin, Vancomycin, Nitrofurantoin, Ciprofloxacin and HLAR gentamicin; Pseudomonas aeruginosa against Amikacin, Cefoperazone, Gentamicin, Ceftazidime and Ciprofloxacin.

7. Results Total patients sampled : 3652
Significant bacterial growth : 363 patients (9.93%) for bacteria
257 cultures (7.04%) showed growth of yeasts (>=105cfu/ml).
7 cultures (0.19%) which showed growth of two pathogens in significant numbers.
Overall 17.16% of the patients had culture positive results.
main ICU
PICU
TXICU
RICU
PSICU
NSICU
CCU
232
123
122 22 56 34 33
% of Total positives
37.06%
19.65%
19.49%
3.51%
8.95%
5.43%
5.27%

8. Table 2 : Estimated urinary colonization by pathogens / 1000 ICU days
Overall
10.32
Main ICU
26.36
PICU
12.81
TxICU
16.71
PSICU
7.67
Figure 1 : Background illnesses in culture positive cases

9. Table 3 : Organisms involved in urinary colonization Organism
Number of culture positive cases %
E. coli
119
19.01
Klebsiella 61
9.74
Enterococcus 68
10.86
Enterobacter 17
2.72
Pseudomonas aeruginosa 53
8.47
Streptococcus spp. 5
0.80
Acinetobacter 20
3.19
yeast
257
41.05
Citrobacter 7
1.12
Proteae
Staphylococcus spp. 6
0.96

10. Legend : ICU= main Intensive care unit, PICU = Pediatric Intensive care unit, TxICU= Transplant Intensive care unit, RICU = respiratory Intensive care unit, PSICU = Pediatric Surgery Intensive care unit, NSICU = Neurosurgery Intensive care unit, CCU = Cardiac Care Unit

11. Table 5: Anitmicrobial Susceptibility profile of the isolates.
Organism
Cefotaxime (%)
Cefoperazone(%)
Gentamicin(%)
Amikacin(%)
Nalidixic acid(%)
Norfloxacin(%)
Ciprofloxacin(%)
Cotrimoxazole (%)
Ceftazidime (%)
Nitrofurantoin (%)
Imipenem*,** (%)
Piperacillin-Tazobactam*,**(%)
Cefoperazone-Sulbactam* (%)
Enterobacteriaceae S
31,
23.7
24,
23.2
34,
24.6
96,
58.2
10,
5.3
21,
11.9
25,
19.6
23,
10.1
114
65.9
76,
96.3
32,
50.9
58.3 I 7,
0.9
1.2 2, 5,
9.2 3,
0.3 9,
2.1 4,
0.6 1,
16,
7.4
0.0
20,
16.7
17,
12.9 R
152,
75.4
155,
75.7
163,
74.2
98,
32.6
186,
95.0
169,
86.1
170,
79.5
162,
89.0
67,
26.7
3.7
26,
32.4
28.7
Pseudomonas
26.5
67.6
14,
41.2
15,
44.1
11,
40.0
21.0
2.9
9.0
70.6
58.8
18,
52.9
22,
64.7
60.0 70

12. S I R Organism Enterococcus 7, 14.0 4, 8.0 28, 56.0 8, 16.0 44, 88.0
Cefotaxime (%)
Cefoperazone (%)
Gentamicin (%)
Amikacin (%)
Nalidixic acid(%)
Norfloxacin (%)
Ciprofloxacin (%)
Cotrimoxazole(%)
Ceftazidime (%)
Nitrofurantoin (%)
Imipenem*,**(%)
Amoxycillin (%)
Vancomycin(%)
Enterococcus S 7,
14.0 4,
8.0
28,
56.0 8,
16.0
44,
88.0 I 2,
4.0 6,
12.0
0.0 R
41,
82.0
16,
32.0
36,
72.0
Acinetobacter 1,
6.3 3,
18.8
12.5 5,
31.3
37.5
62.5
50.0
25.0
15,
93.8
13,
81.3
14,
87.5
11,
68.8
10,
12,
Legends: S= Sensitive, I= Intermediate resistance, R= Resistant
* Tested only for panresistant isolates or patients in whom specifically requested for (108 Enterobacteriaceae and Acinetobacter, Pseudomonas **– 5 isolates)
# Tested for HLAR (120 microgram disc).

13. Discussion
At colonization per 1000 / ICU days, incidence of urinary colonization in our tertiary care center is very high.
However, there was considerable variation between the incidence of UTI in various ICUs, reflecting probably, the variation in misuse of urinary catheters.
Colonization does not equate with urinary tract infection (UTI). Unless clinical signs are present along with pyuria, nosocomial UTI cannot be definitively proven. Positive culture alone is not diagnostic of UTI in ICU patients, unlike other settings.
Specific recommendations exist for diagnosis of nosocomial UTI (Table 6)

14. Catheter associated UTIs in US ICUs during the period 1992 – occurred at a rate of 3.9 ( ) UTIs per 1000 catheter days.
In a study encompassing 55 ICUs in 8 developing countries, catheter associated UTIs ranged from 1.7 to 12.8 per 1000 catheter days (4 to 96 per 1000 ICU days) , mean 8.9 per 1000 catheter days.7
Thus the main drawback of our study is that being a retrospective study we could not estimate the incidence of true UTI, which must be much lower.
Thus we plan a prospective study in the future looking into the clinical details as well.

15. Extensive drug resistance in uropathogens is being reported with increasing frequency from parts of India and other places in the region.
As seen in this study, this problem is accentuated in the ICUs, where use and misuse of antimicrobial agents is the highest.

16. Conclusions
Incidence of intensive care urinary colonization by pathogens at our center is very high.
Frequency of colonization varies from ICU to ICU, and is most probably related to the frequency of misuse of urinary catheterization.
Yeasts have emerged as a very important cause of urinary catheter colonization in ICU patients.

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