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| ORIGINAL ARTICLE |
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| Year : 2022 | Volume
: 9
| Issue : 1 | Page : 3-9 |
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Speciation, risk factors, and antifungal susceptibility pattern of Candida isolates from urine sample of ICU patients: An observational cross-sectional study
Madhusmita Das, Abha Sharma, Poonam S Loomba, Bibhabati Mishra
Department of Microbiology, GIPMER, New Delhi, India
| Date of Submission | 25-Jun-2021 |
| Date of Acceptance | 12-Jan-2022 |
| Date of Web Publication | 20-May-2022 |
Correspondence Address:
Dr. Abha Sharma
Department of Microbiology, GIPMER, New Delhi.
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jhrr.jhrr_11_21
Aim: The presence of Candida species in urine is rarely encountered in healthy people; however, it is of common occurrence in hospitalized patients and in critically ill patients and it may be life-threatening. It is a diagnostic dilemma to differentiate colonization from true infection. The aim of the study is to identify and speciate Candida species in urine, study associated risk factors, and determine the antifungal minimal inhibitory concentrations (MICs) for different species. Materials and Methods: The study was an observational cross-sectional study conducted from March 2019 to December 2019 at the Department of Microbiology, GIPMER, Delhi. All consecutive urine samples received from ICU patients suspected of having urinary tract infection were processed for culture and sensitivity as per standard techniques. CHROM agar and standard yeast identification protocol were used for speciation of Candida species. Antifungal susceptibility testing was performed by VITEK 2 automatic machine. Significant P-value (<0.05) was calculated using Fisher’s exact test. Results: Out of 2963 patients, 250 (8.43%) had candiduria and 50 (20%) had candiduria with pyuria (pus cells> 5/HPF). Out of these 50, 8 (16%) were identified as Candida albicans and 42 (84%) were non-albicans species. The most common species was Candida tropicalis (38%). Duration of catheterization had no significant association with the type of Candida spp. Mechanical ventilation was the most important risk factor associated with non-albicans candiduria when compared with C. albicans (P=0.02). Antifungal susceptibility according to MICs showed 100% resistance to amphotericin B by C. albicans and almost 90% resistance by non-albicans spp. Candida glabrata was 100% resistant to fluconazole, and Candida haemulonii was resistant to all antifungals. Conclusion: Non-albicans Candida are emerging nosocomial pathogens. Candida speciation is important to guide patient management as non-albicans Candida species are more resistant to antifungal drugs. Azoles are more sensitive when compared with amphotericin B. Keywords: Antifungal, Candida species, ICU
How to cite this article:
Das M, Sharma A, Loomba PS, Mishra B. Speciation, risk factors, and antifungal susceptibility pattern of Candida isolates from urine sample of ICU patients: An observational cross-sectional study. J Health Res Rev 2022;9:3-9 |
How to cite this URL:
Das M, Sharma A, Loomba PS, Mishra B. Speciation, risk factors, and antifungal susceptibility pattern of Candida isolates from urine sample of ICU patients: An observational cross-sectional study. J Health Res Rev [serial online] 2022 [cited 2023 Jun 7];9:3-9. Available from: https://www.jhrr.org/text.asp?2022/9/1/3/345548 |
| Introduction | |  |
Candiduria is an important nosocomial infection afflicting the urinary tract.[1] It is defined as the presence of yeast cells in urine.[2] Candiduria in most of the patients is asymptomatic, but in critically ill patients it may be life-threatening.[3],[4] Candiduria or presence of Candida species in the urine is rarely encountered in otherwise healthy people with structurally normal urinary tract.[1],[3] It is of common occurrence in hospitalized patients. Candida species account for almost 10–15% of nosocomial urinary tract infections (UTIs).[3],[5]
Clinicians face a diagnostic dilemma in differentiating colonization from true infection and to decide whether candiduria requires any therapeutic intervention.[4],[6] Due to the increased use of indwelling devices, the incidence of candiduria has been increasing dramatically. With short-term catheterization (up to 7 days), 10–50% of the patients develop infections, whereas in long-term catheterization (>28 days), usually all patients develop UTI. The risk of catheter-associated infections increases by approximately 10% for each day.[7] The microorganisms are introduced into the urethra while (a) the catheter is inserted and (b) through the sheath of the exudates surrounding the catheter or (c) they travel intraluminally from the tube or the collection bag. Besides Candida albicans, the incidence of candiduria which is caused by non-albicans Candida species has been increasing steadily. It is also necessary to identify the isolates of Candida up to the species level, as some of them have an innate resistance to antifungals.[8] The prevalence of true infection has increased significantly over the past few years due to the presence of various predisposing factors in hospitalized patients. The predisposing factors frequently associated with candiduria are urinary tract instrumentation, prior antibiotic use, prolonged hospital stay, extremes of age, diabetes mellitus, female sex, and use of immunosuppressive therapy.[3],[9],[10]C. albicans is the most common yeast isolated in patients with UTI followed by Candida glabrata and Candida tropicalis. However, there are reports of changing pattern with a rising prevalence of non-albicans Candida species. The inherent resistance of non-albicans Candida to fluconazole is well documented, necessitating speciation of Candida in patients with UTI for initiation of appropriate therapy.[11] This study was conducted with the objective to identify and speciate Candida species from urinary isolates and to determine associated risk factors along with antifungal sensitivity pattern.
| Materials and Methods | | |
The present study was an observational cross-sectional study carried over 9 months from March 2019 to December 2019 at the Department of Microbiology, GIPMER, Delhi. Ethical approval was taken from the Institutional Ethics Committee to conduct the study.
Inclusion criteria
All urine samples from catheterized patients admitted in ICU for more than 72 h were included for the study. All urine samples in which microscopy showed >5 pus cells/HPF on direct examination and yeast isolated as pure growth were further speciated to identify the Candida species.
Exclusion criteria
All urine samples of non-catheterized patients, urine samples without pus cells, and urine samples showing mixed growth were excluded from the study.
A proforma was filled regarding demographic and associated risk factors such as age, sex, duration of hospital stay, duration of catheterization, h/o antibiotic usage, and diabetes mellitus, and other clinical details were also obtained.
Processing of specimen
About 2963 urine samples were received from ICU patients suspected of having UTI. The samples were immediately processed in the Microbiology Laboratory, GIPMER, Delhi by semi-quantitative method as per the standard protocols. All the yeast isolates were stocked for further microbiological characterization. Direct wet mount examination of urine was done to look for the presence of pus cells, red blood cells, cast, bacteria, or fungal elements. Gram staining was done to look for Gram-positive yeast cells. Culture was performed on blood agar and MacConkey’s agar and plates were incubated at 37oC for 24 h. Culture was also done on Sabouraud dextrose agar. The isolates were identified as Candida species by Gram staining. Repeat culture was done to rule out contamination. Species identification was done by the germ tube test, culture on CHROM agar, and VITEK 2 Compact System (bioMérieux, Mumbai, India) as per the manufacturer’s instruction, along with antifungal susceptibility testing by VITEK 2 for fluconazole, voriconazole, flucystosine, and amphotericin B. The MICs were interpreted according to the CLSI guidelines 2019.
Statistical analysis
All categorical data were analyzed using GraphPad software (https://www.graphpad.com/quickcalcs/). Significant P-value(<0.05) was calculated using Fisher’s exact test.
| Results | | |
Out of 2963 patients, 250 (8.43%) had candiduria, and 50 (20%) had candiduria with pyuria (pus cells> 5/HPF). Out of these 50, 8 (16%) were identified as C. albicans and 42 (84%) were non-albicans species [Table 1]. The most common non-albicans species was C. tropicalis (38%). Majority of the cases were in the age group of 46–60 years (32%), followed by 16–30 years (22%). In the study, 26 (52%) were males and 24 (48%) were females. Most of the patients (50%) were from medical ICU. Duration of catheterization was more than 7 days in 56% of the patients.
On correlating the clinicodemographic profile according to Candida spp. [Table 2], it was observed that most of the patients who had candiduria due to non-albicans Candida spp. (28%) were in the age group of 46–60 years which was found to be statistically significant (0.0099). The duration of catheterization had no significant association with the type of Candida spp. isolated. This study showed mechanical ventilation to be the most important risk factor associated with non-albicans candiduria when compared with C. albicans as 80% of the patients with non-albicans candiduria were on mechanical ventilation (P=0.02). | Table 2: Correlation of clinico-demographic profile with fungal isolates
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C. tropicalis was the most common species isolated (11/19) from patients who were on catheterization for more than 7 days followed by Candida parapsilosis (8/19) [Table 3]. Among patients with duration of catheter between 3 and 7 days, again C. tropicalis (7/19) was the most common Candida spp. isolated followed by C. glabrata (5/19). | Table 3: Number of various Candida species isolates in relation to duration of catheter
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The MIC of fluconazole for most of the strains of non-albicans Candida [Figure 1] was 1 and 2 while for C. albicans it was <0.5 [Figure 2]. The MIC of most of the strains for voriconazole was <0.2 in both albicans and non-albicans Candida spp. For caspofungin, the MIC was <0.12 in most of the isolates in both albicans and non-albicans spp. The MIC of micafungin was <0.06 in all isolates of C. albicans (100%), whereas it was <0.06 and 0.12 for most of the isolates of non-albicans Candida spp. The MIC of flucytosine was <1 for almost all species of Candida. For amphotericin B, the MIC for most of the isolates of C. albicans was equal to 1, whereas for non-albicans spp., MIC was <0.25 and 0.5 for most of the strains. Interpretation of antifungal MICs for Candida species shows that [Table 4] all isolates of C. albicans (100%) were sensitive to all antifungal agents, except amphotericin B to which all isolates (100%) were resistant. All isolates of C. tropicalis (100%) were sensitive to flucytosine, voriconazole, and micafungin and the most resistant antifungal was amphotericin B (57.8%). For C. parapsilosis, all isolates were sensitive to voriconazole (100%), followed by flucytosine, caspofungin, and fluconazole, whereas resistance to micafungin and amphotericin B was 90% and 80%, respectively. Most of the isolates of C. glabrata (90–100%) were sensitive to flucytosine, voriconazole, caspofungin, and micafungin, whereas all isolates (100%) were resistant to fluconazole and 4/6 isolates were resistant to amphotericin B. All isolates of Candida haemulonii were resistant to all antifungal agents except one isolate which was sensitive to fluconazole. | Figure 1: Antifungal MICs of non-albicans Candida spp.
*FLU=fluconazole; VORI=voriconazole; CASPO=caspofungin; MICA=micafungin; FLUCYT=flucytosine; AMPH B= amphotericin B
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 | Figure 2: Antifungal MICs of C. albicans
*FLU=fluconazole; VORI=voriconazole; CASPO=caspofungin; MICA=micafungin; FLUCYT=flucytosine; AMPH B= amphotericin B
Click here to view |
| Discussion | | |
With the use of indwelling medical devices in the ICU, a significant rise in the incidence of C. albicans and non-albicans Candida infections was reported from various regions.[12]
Kojic et al.[13] reported that medical device-induced infections contributed about half of all the nosocomial infections and that 10% of such infections were due to the Candida species. Nosocomial UTI is the most common healthcare-associated infection. Candida species are increasingly becoming an important causative agent of nosocomial UTI.
In the present study, we observed that candiduria was more common in 46–60 years age group (32%). Similar results were reported by Gharaghani et al.,[14] whereas other studies such as Passos et al.,[9] Kobayashi et al.,[10] and Fisher et al. showed UTI due to Candida spp., which was more common during extremes of age. This could be due to lowered host defenses at extremes of age.
Studies conducted by Bukhary[1] and Lundstrom and Sobel[5] found females to be the most common risk factor in UTI-associated candiduria. As colonization of vulvovestibular area with Candida spp. is frequent in females, they are more at risk of developing candiduria due to ascending infection. However, in the present study, it was found that candiduria was more common in males (52%) when compared with females (48%). Similarly, studies conducted by Chakrabarthi et al.[15] also found increased percentage of candiduria in males.
In a study done by Prasad et al.,[16] the isolation of non-albicans Candida species was higher (52.4%) when compared with that of C. albicans (47.6%), which is consistent with the present study showing non-albicans Candida species (84%) and C. albicans (16%). Similar studies were also reported by Rishpana and Kabbin[17] where from 26 Candida isolates, 16 (61.53%) were non-albicans Candida species and 10 (38.47%) were C. albicans. Our data also indicate a trend toward an increasing prevalence of infections caused by non-albicans Candida species which is not consistent with a study reported by Jain et al.[18] and Sobel et al.,[19] where C. albicans has been the most frequent species isolated from nosocomial UTI.
Among non-albicans Candida species, C. tropicalis 19 (38%) was the most common species, followed by C. parapsilosis 10 (20%), C. glabrata 6 (12%), Candida famata 5 (10%), and C. haemulonii 2 (4%). C. tropicalis 8 (30.76%) was the most commonly encountered species, followed by Candida dubliensis 4 (15.38%), C. parapsilosis 2 (7.69%), and C. glabrata 2 (7.69%), as reported by Rishpana and Kabbin[17] and Gubbins et al.[11] in their studies, which is consistent with the present study.
In the study conducted by Passos et al. and Sales et al.,[20] candiduria was detected in 44.4% (68/153) of the ICU patients, which is similar to our study with 84% (42/50) seen in ICU-admitted patients compared with patients admitted in the ward. The high prevalence of candiduria in ICU patients who are mostly catheterized should be considered very important. According to some authors, e.g., Nassoura et al.,[21] the presence of candiduria in ICU patients might be indicative of urinary tract or systemic infection.
Ahmad et al.[22] and Álvarez-Lerma et al.[23] found that patients with ICU stay >1 week had higher urine Candida colonization than in the admission day, which is similar to our study. Probable sources of nosocomial acquisition in ICU appear to be originated endogenously, but there is also evidence that exogenous infection or cross-infection from nursing staff may occur. It is evident that the risk factors should be considered for acquisition of Candida in urine.
Many risk factors contribute to patient colonization. Catheterized patients admitted in the ICU with other associated risk factors such as diabetes mellitus, previous surgery, and previous history of antibiotic use are at risk of developing nosocomial UTI due to Candida spp. In the presence of associated risk factors, there is a definite risk of invasive candidiasis following candiduria; hence, aggressive approach is warranted by the clinicians.[24] According to the study conducted by Kauffman et al.[3] and Blumberg et al.,[24],[25] use of antibiotics, presence of central venous catheter, and prolonged hospital stay represent important risk factors for the development of microorganism. However, in the present study, it was observed that mechanical ventilation (P = 0.02) was a statistically significant risk factor associated with candiduria in UTI patients. A study by Goeke[26] found diabetes mellitus to be a well-known risk factor for candiduria because diabetes reduces the host resistance to invasion by fungi and also promotes urinary stasis in neurogenic bladder, thus further increasing the chances of colonization of Candida species.
According to a study by Fisher et al.[13] Sobel et al.,[19] prolonged antibiotic use (100%) plays a critical role in the pathogenesis of candiduria, which emerges during antibiotic therapy or immediately after it. By suppressing susceptible endogenous bacterial flora in the gastrointestinal and lower genital tracts, antibiotic favors epithelial surface fungal colonization, with ready access to the urinary tract, specially in the presence of indwelling bladder catheter. Our study too showed prolonged usage of antibiotics supporting the above-mentioned study. The study reported by Schönebeck and Anséhn[25],[27] showed that in most cases of candiduria, the patient had a urinary catheter (92.6%). Similar results have been obtained by Kobayashi et al.,[10] who verified that 84.4% of the patients with candiduria had a catheter which is consistent with our study, showing that all patients with urinary catherization support it.
According to Klotz and Smith (1990), yeasts are able to adhere to the catheter, allowing colonization in this device. Although infection by yeasts in patients with indwelling urinary catheter has not been well defined till now, use of invasive procedures has been reported as an important factor for the development of Candida spp. Infection in the study conducted by Álvarez-Lerma et al.,[23] which is also shown in our study, shows that tracheostomy to be the second most important risk factor contributing to candiduria in ICU patients.
Antifungal susceptibility according to antifungal MICs in our study showed 100% resistance to amphotericin B by C. albicans and almost 90% resistance by non-albicans spp. too, which implies that azoles were more sensitive. However, Candida species were more susceptible to amphotericin (97%) than azoles (itraconazole 60% and fluconazole 36%) in the study conducted by Manikandan and Amsath[27] and Yashavanth et al.,[28] which is not consistent with the present study. In the present study among non-albicans, C. glabrata was 100% resistant to fluconazole and C. haemulonii was resistant to all antifungals. According to a study conducted by Saha et al.,[29]C. albicans is usually sensitive to amphotericin B, whereas non-albicans are more resistant to antifungal drugs, especially fluconazole, which is not similar to our study showing high resistance to amphotericin B but sensitive to azoles, caspofungin, and micafungin. Arora et al.[30] showed in their study that among the 90 Candida isolates tested, all were susceptible to amphotericin B. The non-albicans Candida spp. are more difficult to treat and chances that these strains would remain persistent are higher. Thus species identification should also be performed for appropriate management of patients.
| Conclusion | | |
Candiduria in catheterized patients of ICU is an issue of concern. With the prolong use of indwelling medical devices, Candida infections are on the rise. The infection rate is directly proportional to the number of days during which the catheter was present in the patient. Along with C. albicans, non-albicans Candida species are emerging nosocomial pathogens that also play a major role in hospital-acquired infections. Its isolation from clinical samples cannot be ignored as a non-pathogenic isolate or contaminant. Speciation of Candida is important, as non-albicans Candida species, especially C. glabrata and C. haemulonii, are more resistant to antifungal drugs. There is a change in trend with shift toward non-albicans Candida spp., causing candiduria in ICU. More studies on larger sample size will definitely go a long way in revealing epidemiology, emergence, and spread of non-albicans Candida species.
Acknowledgments
Nil.
Financial support and sponsorship
Not applicable.
Conflicts of interest
None.
Authors’ contributions
MD: Methodology, data collection, analysis, and manuscript preparation; AS: Data analysis and manuscript preparation; PSL: Manuscript editing, formal analysis; BM: Conceptualization, manuscript editing.
Ethical policy and Institutional Review Board statement
This study was conducted after obtaining the approval from Institutional Review Board of the teaching hospital.
Patient declaration of consent
(If in-vivo study/case reports) Not applicable.
Data availability statement
All data are available.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]
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