Seyed Reza Aghili1,2, Mahdi Abastabar1,2, Ameneh Soleimani2, Iman Haghani1,2, Soheil Azizi3. 1. Invasive Fungi Research Center, Communicable Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran. 2. Department of Medical Mycology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran. 3. Department of Laboratory Medicine, Faculty of Allied Medical Sciences, Mazandaran University of Medical Science, Sari, Iran.
Abstract
BACKGROUND AND PURPOSE: Heart failure is a leading cause of hospitalization, and asymptomatic candiduria is common in hospitalized patients with low morbidity. However, in most patients, it is resolved spontaneously on the removal of the catheter. Despite the publication of guidelines, there are still controversies over the diagnosis and management of candiduria. However, in hospitalized patients with heart failure, the decision to treat candiduria is especially important since the nosocomial infections are associated with an increase in morbidity, mortality, length of hospital stay, and healthcare costs. Some species of Candida, such as Candida glabrata, are increasingly resistant to the first-line and second-line antifungal medications. The present study aimed to investigate the incidence of asymptomatic Candida urinary tract infection due to C. glabrata and antifungal susceptibility of Candida isolates in hospitalized patients with heart failure. MATERIALS AND METHODS: In total, 305 hospitalized patients with heart failure were studied to identify asymptomatic nosocomial candiduria during 2016-17 in one private hospital in the north of Iran. The Sabouraud's dextrose agar culture plates with a colony count of >104 colony-forming unit/ml of urine sample were considered as Candida urinary tract infection. Candida species were identified based on the morphology of CHROMagar Candida (manufactured by CHROMagar, France) and PCR-RFLP method with MspI restriction enzyme. Antifungal susceptibility testing of the isolates was performed using five mediations, including itraconazole, voriconazole, fluconazole, amphotericin B, and caspofungin by broth microdilution method according to CLSI M27-S4. RESULTS: In this study, the rate of asymptomatic Candida urinary tract infection was 18.8%, which was more common in people above 51 years old and females (70%). In addition to the urinary and intravascular catheter, the occurrence of candiduria in hospitalized patients had significant relationships with a history of surgical intervention, diastolic heart failure, and use of systemic antibiotics (P>0.05). Among Candida spp., non-albicans Candida species was the most common infectious agent (59.7%). Moreover, C. glabrata (n=27, 40.3%) (alone or with other species) and Candida albicans (n=27, 40.3%) were the most common agents isolated in Candida urinary tract infection. Based on the results of the in vitro susceptibility test, the C. glabrata isolates were 15%, 59%, 70%, 74%, and 85% susceptible to caspofungin, amphotericin B, itraconazole, voriconazole, and fluconazole, respectively. CONCLUSION: According to the findings, there was a high prevalence of asymptomatic Candida urinary tract infection in hospitalized patients with heart failure. Besides, it was suggested that there was a shift towards non-albicans Candida, especially C. glabrata, in these patients. Therefore, asymptomatic candiduria in hospitalized patients with heart failure should be considered significant. Furthermore, the identification of Candida species along with antifungal susceptibility is essential and helps the clinicians to select the appropriate antifungal agent for better management of such cases. Copyright:
BACKGROUND AND PURPOSE: Heart failure is a leading cause of hospitalization, and asymptomatic candiduria is common in hospitalized patients with low morbidity. However, in most patients, it is resolved spontaneously on the removal of the catheter. Despite the publication of guidelines, there are still controversies over the diagnosis and management of candiduria. However, in hospitalized patients with heart failure, the decision to treat candiduria is especially important since the nosocomial infections are associated with an increase in morbidity, mortality, length of hospital stay, and healthcare costs. Some species of Candida, such as Candida glabrata, are increasingly resistant to the first-line and second-line antifungal medications. The present study aimed to investigate the incidence of asymptomatic Candida urinary tract infection due to C. glabrata and antifungal susceptibility of Candida isolates in hospitalized patients with heart failure. MATERIALS AND METHODS: In total, 305 hospitalized patients with heart failure were studied to identify asymptomatic nosocomial candiduria during 2016-17 in one private hospital in the north of Iran. The Sabouraud's dextrose agar culture plates with a colony count of >104 colony-forming unit/ml of urine sample were considered as Candida urinary tract infection. Candida species were identified based on the morphology of CHROMagar Candida (manufactured by CHROMagar, France) and PCR-RFLP method with MspI restriction enzyme. Antifungal susceptibility testing of the isolates was performed using five mediations, including itraconazole, voriconazole, fluconazole, amphotericin B, and caspofungin by broth microdilution method according to CLSI M27-S4. RESULTS: In this study, the rate of asymptomatic Candida urinary tract infection was 18.8%, which was more common in people above 51 years old and females (70%). In addition to the urinary and intravascular catheter, the occurrence of candiduria in hospitalized patients had significant relationships with a history of surgical intervention, diastolic heart failure, and use of systemic antibiotics (P>0.05). Among Candida spp., non-albicans Candida species was the most common infectious agent (59.7%). Moreover, C. glabrata (n=27, 40.3%) (alone or with other species) and Candida albicans (n=27, 40.3%) were the most common agents isolated in Candida urinary tract infection. Based on the results of the in vitro susceptibility test, the C. glabrata isolates were 15%, 59%, 70%, 74%, and 85% susceptible to caspofungin, amphotericin B, itraconazole, voriconazole, and fluconazole, respectively. CONCLUSION: According to the findings, there was a high prevalence of asymptomatic Candida urinary tract infection in hospitalized patients with heart failure. Besides, it was suggested that there was a shift towards non-albicans Candida, especially C. glabrata, in these patients. Therefore, asymptomatic candiduria in hospitalized patients with heart failure should be considered significant. Furthermore, the identification of Candida species along with antifungal susceptibility is essential and helps the clinicians to select the appropriate antifungal agent for better management of such cases. Copyright:
Heart failure (HF) is a leading cause of hospitalization among the elderly
(i.e., people over 65 years old) in the world, and hospitalization
is associated with substantial mortality rates. The HF and diabetes
are two diseases associated with metabolic disorders since they lead
to imbalance or abnormalities in biochemical and physiological factors
of the human body [ 1
, 2
]. Rate of co-existence of HF and diabetes has been reported to be as high as almost 40% [ 2
]. Infections are the main co-morbidities diagnosed in hospitalized HF patients [ 3
].Alon et al. in their research project studied 9,335 HF patients and found that 3,530 (38%) of them were hospitalized at least once due to urinary tract infections (UTIs) which is one of the most frequent diagnoses in these patients (15.7%) [ 4
]. The UTIs are caused by microbes, such as bacteria and fungi, and can affect the kidneys, bladder, and the tubes that run between them. The heart and small intestine are connected to urinary systems and the most relevant organs to UTIs [ 5
]. Based on previous studies, this infection occurs more often in females, compared to males, with a ratio of 8:1 [ 6
].Moreover, the findings of previous studies have indicated that almost 50% of hospitalized patients with HF use urinary catheters due to urinary incontinence and overactive bladder [ 7
, 8
]. Urinary catheterization increases the risk of nosocomial UTIs up to 97% [ 9
] and the longer durations of catheter usage lead to the appearance of more infectious organisms
in the urine [ 10
]. Fungal UTIs caused by yeast, such as Candida species, have increased in hospitalized patients
over the last decade, especially HF patients [ 11
].Candiduria (i.e., the presence of Candida yeasts in urine) is a marker of colonization or
infection in the lower or upper urinary tract by Candida species. Patients with candiduria
can be categorized as asymptomatic or symptomatic based on the diagnostic criteria and
obtained data. Asymptomatic candiduria is defined as a positive urine culture
with ≥ 103 yeast colonies/ml in the absence of dysuria, polyuria, flank pain,
and/or fever. Asymptomatic catheter-associated candiduria is common in hospitalized patients
and has low morbidity. Moreover, it is resolved spontaneously by the removal of the catheter
in most patients. Despite the publications of guidelines in this regard, there are controversies
over the diagnosis and management of candiduria [ 12
, 13
].Moreover, candiduria may be a symptom of systemic candidiasis which is developed due to
hematogenous seeding of yeast in patients. Clinical findings vary and often include
asymptomatic or rarely symptomatic patients with cystitis, pyelonephritis, prostatitis,
epididymo-orchitis, or urinary tract fungus balls. Despite the fact that
Candida albicans
species is the most frequently identified isolate of candiduria in hospitals, non-albicans Candida
species now account for a significant proportion of clinical isolates collected worldwide in hospitals. Furthermore, they are also important due to the increasing resistance to antifungal agents [ 14
, 15
].Candiduria caused by Candida glabrata is now more common than that caused
by other Candida species in some geographic areas and some patient
groups [ 16
- 18
]. The C. glabrata infections have a high mortality rate in
immunocompromised hospitalized patients; therefore, it is essential to evaluate
candidiasis in hospitalized patients with HF. Regarding the high resistance of
some non-albicans Candida species, such as C. glabrata and
C. krusei, to antifungal
agents [ 19
, 20
], the isolation and detection of species of the infecting agent in urine samples of HF patients
should be considered important for the treatment.In this study, a laboratory-based survey was conducted using the CHROMagar Candida (CHROM agar, France) culture and polymerase chain reaction-restriction fragment length
polymorphism (PCR-RFLP) method with MspI restriction enzyme for the identification of
candiduria agents. Moreover, antifungal susceptibility tests were performed on the isolates
using the broth microdilution method and Clinical Laboratory Standards Institute (CLSI) documents
with five medications to find the most appropriate treatment. Based on the results of the present
study, C. glabrata is an emerging menace that leads to the development of candiduria in
hospitalized patients with HF.
Materials and Methods
This prospective, descriptive cross-sectional, laboratory-based surveillance study was carried
out from July 2016 to December 2017 in a Private Heart Center in Sari, north of Iran. In total,
305 hospitalized patients
with HF were investigated to identify asymptomatic candiduria and determine their etiologic
agents. This research was approved by the Ethics Committee of Mazandaran University of Medical
Sciences, Sari, Iran
(ethics code: IR.MAZUMS.REC.96.3045). In this regard, informed consent was obtained from the
patients and they were told that their participation was voluntary; accordingly, they were able
to withdraw from the study
at any stage without any consequences.According to the research objectives, the HF patients included in the study had no previous or current urinary tract infection based on the physical examination on the day of their admission to the hospital. Moreover,
they had been using an indwelling urinary catheter for more than three days by the time of the study. The patients who did not use a urinary catheter, had been using a urinary catheter for less than three days, and had a previous or current urinary tract infection were excluded from the study. The required data were collected through questionnaires and included demographic characteristics (e.g., age and gender), underlying diseases (e.g., diabetes and a form of HF), and risk factors (e.g., long hospital stay, usage of several catheters, and treatment with antibiotics, corticosteroids, and antifungal medications).In total, 580 urine samples were collected from 305 HF patients and transferred immediately to
the hospital pathology lab. A urine wet mount examination was performed to check for pus cells,
red blood cells, or any fungal
elements. In total, 100 µl of each un-centrifuged urine sample was cultured after shaking two
culture media. One sample was cultured on Sabouraud’s dextrose agar (SDA) (manufactured by Quelab,
Canada) with chloramphenicol (100mg/L) and the other sample was cultured on brain heart infusion
agar (BHI) (manufactured by Quelab) with chloramphenicol (100mg/L).All plates were incubated at 37 °C up to a maximum of one week. The Candida species that were
cultivated on culture plates with a colony count of > 104 colony-forming
unit (CFU)/ml
or 103 < colony count < 104 CFU/ml associated with pyuria in urine sample were considered significant. Subsequently, 5-10 ml of blood sample of patients with candiduria was collected by
venipuncture aseptically and processed according to the standard protocols.
Isolates identification and antifungal susceptibility testing
The species were identified based on colony morphology on CHRO Magar Candida
and the PCR-RFLP method [ 21
]. The PCR-RFLP method was performed by genomic DNA extraction by the phenol-chloroform and
amplification of yeast gene using the internal transcribed spacer (ITS) 1
(forward: 5´-TCCGTA-GGT-GAA-CCT-GCG-G-3´) and ITS4 (reverse: 5´-TCC-TCC-GCT-TATTGA-TAT-GC-3´)
primers (manufactured by MWG-Biotech AG, Germany). Afterward, the MspI
restriction enzyme (manufactured by Thermo Fisher Scientific, USA) was used for the digestion of
PCR products, and restriction fragments were separated using 2% agarose gel electrophoresis.
Figure 1 shows the exact size of digested ITS-PCR products of some isolates.
Figure 1
Agarose gel electrophoresis of digested ITS-PCR products of some isolates. M: molecular marker, A: Candida glabrata, B: Candida albicans, C: Candida glabrata, D: Candida tropicalis,
E: Candida glabrata, F: Candida glabrata, G: Candida albicans, and H: Candida parapsilosis
Agarose gel electrophoresis of digested ITS-PCR products of some isolates. M: molecular marker, A: Candida glabrata, B: Candida albicans, C: Candida glabrata, D: Candida tropicalis,
E: Candida glabrata, F: Candida glabrata, G: Candida albicans, and H: Candida parapsilosisThe MspI enzyme cannot cause cleavage in the ITS region of
C. parapsilosis. Therefore,
the PCR- Hyphal wall protein 1 (HWP1) discriminatory pattern was performed
by the amplification of the HWP1 gene as described by Abastabar et al. [ 22
] to distinguish C. parapsilosis and C. orthopsilosis. The PCR amplification of the HWP1 gene for
C. parapsilosis was achieved using the forward,
5′-CGAGG TGAATATGATGCTTGTA-3′
and reverse, 5′-CCAACAGAATTGCTTAATACCATA-3′, for C. orthopsilosis forward, 5′-ACCACCACCTAGTTCTGAG-3′
and reverse, and 5′-TCACTTGGAAGATTGAGAATAACA-3′ primer pairs. They produce two different
DNA fragments which are approximately 840 and 900 bp for C. parapsilosis
and C. orthopsilosis,
respectively.For Candida species isolates, in-vitro antifungal susceptibility
testing was performed
using broth microdilution and CLSI document M27-S4 (Reference Method for Broth Dilution
Antifungal
Susceptibility Testing of Yeasts, Approved Standard, CLSI, Wayne, PA, USA, 2012.)
[ 23
]. All isolated Candida species were tested by fluconazole (FLC) and voriconazole (VRC)
(Pfizer, Sandwich, United Kingdom), itraconazole (ITC) (manufactured by Janssen, Belgium),
caspofungin (CAS) (manufactured by Merck Sharp & Dohme B.V.), and amphotericin B (AMB)
(manufactured by Bristol-Myers-Squibb, The Netherlands).
The C. parapsilosis (ATCC 22019) and
C. krusei (ATCC 6258)
strains were used as the controls.Powders of ITC, VRC, AMB, CAS, and FLC antifungal agents were obtained from the manufacturers.
Final concentrations of antifungal agents in the wells were within the ranges of 0.016-16 μg/ml
for ITC, VRC, and AMB,
0.008-8 μg/ml for CAS, and 0.064-64 μg/ml for FLC. Stock solutions of medications were prepared
in dimethyl sulfoxide except for CAS and FLC which were dissolved in sterile water and
stored at –80 °C until they were used.The isolated Candida species were grown on SDA and incubated at 35 °C for 48 h.
A spectrophotometer at 530 nm was used to adjust a conidial inoculum with a range of 1-5⨯105 CFU/ml by suspensions diluted in RPMI
1640 medium. The medication containing 96-well plastic micro-plates was inoculated with this suspension and incubated at 35 °C for 24–48 h. The minimum inhibitory concentrations (MICs) of FLC, VRC, CAS, ITC,
and amphotericin B were determined according to the CLSI M27-S4 guidelines. Resistance
breakpoints for Candida species to the different antifungal medications were also selected
based on CLSI M27-S4 guidelines
[ 24
].
Statistical analysis
The collected data were analyzed in SPSS software (version 19) and the quantitative variables
were described using mean and standard deviation. Moreover, the percentage and
frequency were calculated for qualitative variables. The Chi-square test and
t-test were used to determine differences between experimental factors and the
association of the groups with each other. In addition, non-parametric tests
were used to compare the two groups. It should be noted that a p-value of less than
0.05 was considered statistically significant.
Results
According to the mycology laboratory results, out of the 305 hospitalized patients who met the
inclusion criteria, 58 (18.8%) cases had asymptomatic Candida urinary tract infection
(Candida colony count: >104 CFU/ml or
103
Figure 2
Frequency of Candida species isolated from heart disorder patients with asymptomatic candiduria
Frequency of Candida species isolated from heart disorder patients with asymptomatic candiduriaNo positive blood culture was found in patients with candiduria. The clinical information and
demographic features of 305 patients were collected for the purposes of the study. In total,
183 (57.9%) of subjects were female and 122 (42.1%) of them were male. The patients were within
the age range of 31-88 years and their mean age was 67.6 years. Based on the results, female
subjects were at higher risk of heart disease, compared to males; however, this difference was
not significant (P>0.05). Prevalence of heart disorders was different in various age
groups and peaked at age ranges of 51-65 and 66-80 years in both males and females. Intravascular
catheter insertion (95%), diastolic HF (62.8%), history of surgery (62.0%), coronary artery
bypass grafting (59.9%), diabetes mellitus (58.6%), use of broad-spectrum antibacterial
antibiotics (57.1%), and hospitalization for seven days or more (44.3%) were the major
underlying conditions in these patients (Figure 3).
Figure 3
Percentage frequency of underlying condition in patients with a heart disorder
Percentage frequency of underlying condition in patients with a heart disorderBased on their medical records, 159 (59.1%) cases had diabetes as an added underlying condition.
Moreover, heart disorders were associated with diabetes in 60.7% and 39.3% of female and
male patients, respectively. However, diabetes caused no statistically significant difference
between patients with and without candiduria (P> 0.05).The most common underlying conditions significantly associated with candiduria in hospitalized patients with HF were a history of surgical intervention, diastolic HF, and systemic antibiotics therapy (P<0.05).The C. albicans (40% alone and 6.9% co-isolated with
C. glabrata) and C. glabrata (31% alone and 15.5% co-isolated
with other species) had the most prevalence as candiduria agents
( Table 1). In total, nine patients had mixed infection
caused by two different Candida species. All the mixed infection cases were
caused by
C. glabrata mixed with other species (four cases of
C. glabrata+C. albicans, two cases of
C. glabrata+C. tropicalis, two cases of
C. glabrata+C. parapsilosis, and one case of
C. glabrata+C. krusei).
Table 1
Distribution of Candida spp. among heart failure patients with candiduria
Candida spp.
Frequency number (%)
Male
Female
Total
Candida glabrata
5 (28)
13 (33)
18 (31)
Candida albicans
6 (33)
17 (43)
23 (40)
Candida tropicalis
2 (11)
1 (2)
3 (5)
Candida krusei
1 (6)
1 (2)
2 (3)
Candida parapsilosis
0 (0)
3 (8)
3 (5)
Mixed infection
4 (22)
5 (12)
9 (16)
Total
18 (100)
40 (100)
58 (100)
Distribution of Candida spp. among heart failure patients with candiduria
Susceptibility test results
The recent CLSI clinical M27-S4 approved breakpoint values were used for identification of
the susceptibility of Candida species to antifungal medications
[ 25
]. Table 2 summarizes the main points of in vitro
activity of five antifungal medications against all 67 isolates of Candida species. The
FLC (0.25-64 μg/ml) showed the widest MIC range for all candidate species while VRC and
AMB had the narrowest MIC range (0.016–16 μg/ml). The CAS and VRC had the lowest geometric
mean MIC values against C. albicans (0.65 µg/mL) while C. glabrata (0.44 µg/mL) had the
lowest geometric mean MIC value against VRC.
Table 2
Activities of five antifungal medications against clinical isolates of five Candida species
Antifungal agent
Isolated Candida species
No. isolated
MIC 50 (µg/ml)
MIC 90 (µg/ml)
MIC Range
Geometric Mean
MIC Breakpoint M27S4 R (µg/ml)
Resistant No. (%)
Amphotericin B
C. albicans
27
2
4
0.016-8
1.43
>2
5 (18.5%)
C. glabrata
27
2
16
0.25-16
2.40
>2
11 (40.7%)
C. tropicalis
5
0.5
ND
0.5-2
ND
>2
0 (0%)
C. parapsilosis
5
1
ND
1-2
ND
>2
0 (0%)
C. krusei
3
2
ND
2-8
ND
>2
1 (33.3%)
Caspofungin
C. albicans
27
0.5
4
0.032-16
0.65
≥1
12 (44.4%)
C. glabrata
27
1
4
0.032-8
1.08
≥0.5
23 (85.2%)
C. tropicalis
5
2
ND
0.125-8
ND
≥1
3 (100%)
C. parapsilosis
5
1
ND
0.25-8
ND
≥8
2 (40%)
C. krusei
3
2
ND
1-4
ND
≥1
2 (66.8%)
Itraconazole
C. albicans
27
16
16
0.032-16
4.32
≥1
20 (74.1%)
C. glabrata
27
2
16
0.5-16
2.28
≥1
8 (29.6%)
C. tropicalis
5
1
ND
1-16
ND
≥1
2 (40%)
C. parapsilosis
5
1
ND
0.5-1
ND
≥1
5 (100%)
C. krusei
3
16
ND
2-16
ND
≥1
3 (100%)
Voriconazole
C. albicans
27
16
16
0.016-16
2.22
≥1
19 (70.4%)
C. glabrata
27
0.125
16
0.0625-16
0.44
≥1
7 (25.9%)
C. tropicalis
5
0.5
ND
0.0625-16
ND
≥1
2 (40%)
C. parapsilosis
5
0.0625
ND
0.032- 0.125
ND
≥1
0 (0%)
C. krusei
3
16
ND
0.5-16
ND
≥2
2 (66.8%)
Fluconazole
C. albicans
27
64
64
0.25-64
14.81
≥8
19 (70.4%)
C. glabrata
27
8
64
2-64
11.46
≥64
7 (14.8%)
C. tropicalis
5
4
ND
2-64
ND
≥8
2 (40%)
C. parapsilosis
5
4
ND
2-16
ND
≥8
1 (20%)
C. krusei
3
64
ND
64
ND
≥8
3 (100%)
MIC: minimum inhibitory concentration>
Among the isolated Candida species, C. albicans showed
the greatest sensitivity to AMB
(n=22; 81.5%) and CAS (n=15; 63.6%), in that order. Furthermore, the C. glabrata showed
the greatest resistance and sensitivity to CAS (n=23; 85.2%) and VRC, in that order.
All of the isolated C. krusei were resistant to ITC and FLU. The AMB was the
most
active medication particularly against C. tropicalis
and C. parapsilosis. ITC, while
FLU and VRC showed less activity against C. albicans, C. krusei, and
C. tropicalis, in
that order. However, in this study, ITC, VRC, and FLU had the most activity against
C. glabrata isolates and more isolates in this species showed resistance to CAS and AMB.Activities of five antifungal medications against clinical isolates of five Candida speciesMIC: minimum inhibitory concentration>
Discussion
The C. albicans was the most important yeast associated with human
candiduria in the last decades. Reported incidence of candiduria varies (10-30%) in
different geographical locations [ 26
- 29
]. In addition, this rate has increased due to the use of broad-spectrum antibiotics [ 30
] or other underlying conditions, such as old age [ 31
], HF disease [ 32
], and long hospital stay [ 33
].The C. glabrata is a non-pathogenic normal flora of healthy individuals,
and it is rarely associated with candiduria in hospitalized patients
[ 34
]. However, it is now the second or third most frequently
isolated Candida species from Candida
urinary tract infection [ 35
- 37
]. In the last two decades, an important shift was observed in nosocomial Candida infections
regarding the type of Candida species from C. albicans to more treatment-resistant non-albicans
species [ 38
, 39
]. Moreover, according to previous studies, the prevalence of candiduria caused
by C. glabrata has increased in the last two decades [ 40
- 42
] which has raised concerns in the medical mycology due to the organisms therapeutic problems and resistance to common antifungal medications.In the present study, it was found that similar to C. albicans, C. glabrata was
associated with candiduria in HF patients. Moreover, the mixed growth of C. glabrata
and other Candida species
(i.e., C. albicans, C. tropicalis, C. parapsilosis, and C. krusei) were
observed in nine patients. Based on the results of some studies
, C. glabrata establishes competitive interactions with other species during biofilm
formation and candidiasis development [ 43
, 44
]. According to the findings of other studies in Iran, Candida albicans is the most
common isolated species from candiduric patients (50–70%). However, recently, due to the increasing
resistance to antifungal medications, non-albicans Candida species, including,
C. glabrata
(almost 20%), C. krusei, C. parapsilosis, and C. tropicalis have also been implicated [ 45
- 47
].Occurrence of candiduria in hospitalized HF patients, even asymptomatic forms, increases the length of hospital stay and economic costs and contributes to antifungal overuse. Candiduria should be followed up among these patients since it can lead to some invasive candidiasis in them [ 48
]. Catheters are the most common medical devices and almost two billion bladder catheters are inserted annually in the world [ 49
]. In order to monitor urine output, it is common to use urinary catheterization in hospitalized patients with HF. However, the risk of urinary complications increases in long-term usage [ 50
].It is worth mentioning that the rate of catheter-associated infection was 10-30% overall [ 51
]. Findings of the present study indicated that HF was more common in females, compared to men; nevertheless, the difference was not significant. According to previous studies, the incidence rate of HF has been rising faster in females (9%), compared to males (6%) during the past 20 years [ 52
]. However, Ho et al. in a study performed in Framingham, USA found that the incidence of HF was significantly higher in males, compared to females in all age ranges [ 53
].Despite the fact that HF occurs in all ages, Health Harvard Publication reported that in the USA, the first heart attack usually occurs in people above 65 years old and it is the leading cause of death [ 54
]. Findings of various research, including the present study, have indicated that intravascular catheter insertion [ 55
], diastolic HF [ 56
], history of surgery [ 57
] particularly coronary artery bypass grafting [ 58
], use of broad-spectrum antibacterial antibiotics [ 59
], and staying in hospital for seven days or more [ 46
] are major risk factors for candiduria in HF patients which are also statistically significant.In this study, diabetes was a co-morbidity for over half of HF patients (58.6%); however, there was no significant difference in this regard between the patients with candiduria and patients without candiduria. Therefore, diabetes is a risk factor for HF patients, and the problems due to HF are considered as predisposing factors for opportunistic infection, such as candidiasis [ 59
]. Many types of medical devices have been used for the treatment of HF patients which can lead to a potential risk of the adhesion of Candida species and cause biofilm-associated candiduria. In recent years, several studies conducted in Iran [ 46
, 60
, 61
] and around the world [ 62
] have focused on the role of non‐albicans Candida species, especially C. glabrata, in candiduria.In this study, CAS and AMB were the most active antifungals for both C. albicans and
C. glabrata isolates. Shokohi et al. [ 63
] reported 98% and 99.5% susceptibility to CAS and AMB in C. albicans isolated from
cancer patients in the north of Iran.The C. albicans strains were 74.1%, 70.4%, and 70.4% resistant to ITC, VRC,
and FLU, respectively, while, C. glabrata isolates were 29.6%, 25.9%, and 14.8%
resistant to ITC, VRC, and FLU, respectively. Aslani et al. have also reported
that C. albicans isolates are highly resistant to ITC, VRC, and
FLU [ 64
]. According to the findings of previous studies, resistance to azoles in C. glabrata has a multifactorial nature [ 65
]. Based on the results of a study conducted by Amirrajab N. et al. [ 66
], the overall rates of resistance to ITC, VRC, and FLU were 72.5%, 47.5%, and 10% respectively, which are inconsistent with those of the present study.Incipient menace of non-albicans species other than C. albicans and mixed infections, such as candiduria, in hospitalized patients with HF, indicates that the epidemiology of candiduria agents is changing. These types of infections may need higher doses or special antifungal agents and may be resistant to common treatment.Therefore, treatment of candiduria in these patients with FLU, CAS, and AMB may be inefficient.
Improved diagnosis methods, such as culture on to chromogenic media and PCR-RFLP molecular
detection, have shown that other candida species are important pathogens [ 67
].
Conclusion
Based on the findings of this study, there was a high prevalence of asymptomatic nosocomial
candiduria in hospitalized patients with HF. It is suggested to shift towards
non-albicans Candida, especially C. glabrata in these hospitalized
patients. Candiduria may be the first symptom of disseminated candidiasis with high morbidity and
mortality, especially in the presence of risk factors, such as immunosuppression, catheterization,
cardiovascular disease, prolonged hospital stay, and use of antibacterial antibiotics.
Recognition and management of these patients are difficult for clinicians since it has no
typical symptoms. Susceptibility of C. glabrata to antifungal agents is different
from C. albicans and other candida species; therefore, asymptomatic nosocomial
candiduria in HF patients should be considered. Identification of Candida species along with antifungal susceptibility is important and helps the clinicians to select the appropriate antifungal agent for better management of such cases.
Authors’ contribution
SR. A. conceived the study. A. S. and S. A. prepared the strains. A. S. and I. H. performed the experiments. SA. A. and M. A prepared the manuscript. All authors read and approved the final manuscript.
Financial disclosure
No financial interests related to the material of this manuscript have been declared.
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