Introduction

Candiduria, or presence of Candida species in the urine, is a common clinical problem. It is most frequently seen in patients with indwelling urinary catheters.1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 Development is strongly associated with antibiotic use1, 2, 3, 4, 5, 7, 9, 10, 11, 12, 13 and intensive care unit admission.3, 4, 6, 8, 9, 12, 14 Other risk factors include diabetes mellitus,2, 4, 7, 9, 12 female gender,4, 5, 8, 12 organ transplantation,4, 15, 16 surgery,5, 14 central venous catheters7, 17 and malnutrition or parenteral nutrition.4, 7, 10, 12

Neurogenic bladder has also been associated with the development of candiduria.4 Many patients with spinal cord injury (SCI) or dysfunction, as well as other causes of neurogenic bladder dysfunction, may require the long-term use of either indwelling or intermittent catheterization.

Previous studies have shown that despite therapy, most patients with candiduria will develop the infection again2, 3, 5, 8, 9, 13 and that complications such as invasive candidiasis are rare.14, 18, 19 However, there are no studies that specifically examine the role of candiduria in patients with SCI and long-term catheter use. In this study, we determined the occurrence of candiduria in a population of inpatients and outpatients, who were evaluated and treated at our spinal cord injury center with SCI or multiple sclerosis and chronic urinary catheter usage.

Methods

The study was approved by the institutional review board at our facility. All applicable institutional and governmental regulations regarding the ethical use of human volunteers were followed during the course of this research. After witnessed informed consent, a urine sample was obtained from each participant using standard collection techniques. One portion was separated for urinalysis and the other sent for culture. Samples were processed according to our local microbiology laboratory protocol. Patient clinical and demographic data were collected through clinic interview and electronic medical record review.

Participants

Participants consisted of a convenience sample of asymptomatic outpatients presenting to our SCI clinics and of patients admitted to our inpatient SCI unit. Patients were enrolled sequentially as they were encountered. The enrollment period extended from December 2005 to May 2007. Excluded were individuals who were unable to give informed consent either in person or through an authorized representative, and those who did not use a urinary catheter.

Statistical analysis

Continuous parameters were reported as mean±s.d., and discrete parameters were reported as a percent (%). Associations between pairs of discrete parameters were compared with the Pearson χ2-test. All analyses were performed with SAS 9.1 and SPSS 14.0 for Windows.

Results

Table 1 shows demographic variables for our population. In total, 52% had paraplegia, 45% tetraplegia and 3% multiple sclerosis. Average duration of injury among individuals with SCI was 15.8±13.1 years. Samples were evenly divided between those obtained in the SCI clinic and the inpatient unit. No samples were obtained from patients admitted to the intensive care unit. Etiologies of paralysis are shown in Table 2.

Table 1 Patient demographics
Table 2 Etiology of paralysis

Of 100 patients, 66 (66%) used an indwelling (urethral or suprapubic) catheter as their current primary method of management; the remainder used intermittent catheterization (Table 3). The mean duration of catheter usage was 9.6±11 years (range: 2 months–48 years).

Table 3 Bladder management and duration of catheter usage (in years)

Of 100 patients, 17 had urine cultures positive for Candida species (Table 4). This represented an occurrence of 17% (3.76% s.e., ±7.48%, 95% confidence interval (CI)) over the study period. Of 97 patients, 58 had received antibiotics within 2 months of the study of their urine culture. Three patients had unknown status because they resorted to care outside our facility. Of 58 patients, 41 did not have urine cultures positive for Candida. All of the 17 patients with positive Candida cultures were verified as having received antibiotics within the previous 2 months. Of these 17 patients, 12 with positive cultures for Candida were in-patients at the time of their sampling. Three patients also had diabetes mellitus. One patient was later found to have colon cancer.

Table 4 Candida results

Antibiotic use was also significantly associated with the presence of candiduria (χ2(1)=11.9, P<0.01). Patients taking antibiotics were over 14 times more likely to develop candiduria. The use of indwelling (urethral or suprapubic) catheters was significantly associated with the presence of candiduria (χ2(1)=7.2, P<0.01). Patients who used indwelling catheters were over 10 times more likely to develop candiduria (OR=10.6; 95% CI: 1.3–83.5). When the method of catheterization was analyzed specifically, Foley and SPT catheters were associated with a significantly larger likelihood of developing candiduria than CIC catheters (χ2(2)=7.0, P=0.03). There were no differences in the occurrence of candiduria between Foley and SPT catheter use (χ2(1)=0.2, P=0.65).

Of the patients with positive Candida urine cultures, 1 died in 3 months, 1 was lost to follow-up and 15 were alive at 1-year follow-up. Four patients had recurrence of Candida in urine cultures 3 months after the original culture. All of these patients had continued to receive frequent antibiotics. In one of these patients, the species of Candida was different from that originally identified.

No patients had unstable vital signs at the time of sample collection. Of 17 (94%) patients, 16 with candiduria had indwelling (urethral or suprapubic) catheters; only one patient was using intermittent catheterization (Table 5). No patients in our sample required treatment for symptomatic or invasive candidiasis.

Table 5 Bladder management of patients with candiduria

Overall, the cultures of 59 patients had bacterial but not yeast growth and those of 24 patients had no growth of any organism (Table 6). Of these 24 patients, 14 used indwelling (urethral or suprapubic) catheters and 10 used CIC. Of 24 patients, 11 with no urine growth had received antibiotics within the previous 2 months. Of these 11 patients, 7 used indwelling catheters, and the other 4 used CIC.

Table 6 Bacterial cultures

No patients were found with cultures that grew both bacteria and yeast. Urinalysis results were available from 95 persons and are shown in Table 7. All patients with candiduria had positive leukocyte esterase in their urine, and 7 of 17 patients had a positive reaction for nitrite (Table 8). The most common antibiotics used in patients who developed candiduria were fluoroquinolones (7 patients) and vancomycin (6 patients). Two patients were on suppressive therapy with nitrofurantoin. The indications for antibiotic use varied, including urinary tract infection, osteomyelitis and other infections.

Table 7 Urinalyses
Table 8 Characteristics of subjects with candiduria

Discussion

The occurrence of candiduria was fairly low in our sample, despite heavy antibiotic use. In addition, candiduria was not persistent in most (76%) of these patients. Our sample was fairly evenly divided between inpatients and outpatients, and among catheter usage groups. These data indicate an association between antibiotic use and indwelling catheter use and the development of candiduria. However, its association was dependent on antibiotic use. Indwelling catheters are known to be associated with an increased risk of urinary tract infection and subsequent need for antibiotics.

Prior antibiotic use was necessary for the development of candiduria, but only a small percentage of patients who had received antibiotics had positive urine cultures for Candida species. Antibiotics are used more frequently in the SCI population as opposed to the general population, with the most common indications being urinary tract infections, osteomyelitis or pneumonia. Patients who used indwelling catheters were much more likely to have candiduria documented than patients using intermittent catheterization. Patients who developed candiduria were also more likely to be inpatients.

Candiduria did not serve as a marker for adverse outcomes in this study, although our study population did not have significant comorbidities such as transplantation, HIV-positive status or immunosuppression owing to chemotherapy.

One limitation of this study was that we did not include patients who were in an intensive care unit at the time of their sample; instead, we sampled patients in our inpatient unit and outpatient clinic. The presence of Candiduria may be associated with poor outcomes in this population. Conversely, patients who are severely ill and/or have recurrent symptomatic infections requiring multiple courses of antibiotics would be expected to contract candiduria with increasing frequency.

Conclusion

Candiduria was a common occurrence in this sample and was exclusively associated with prior antibiotic use. Patients with indwelling catheters were much more likely to have candiduria than patients using intermittent catheterization. No adverse outcomes were associated with candiduria in this SCI population.