|Year : 2016 | Volume
| Issue : 1 | Page : 32-35
Characterisation and antifungal susceptibility profile of Candida species isolated froma tertiary care hospital
Prasadini Guru, Geetha Raveendran
Department of Microbiology, Government Medical College, Thiruvananthapuram, Kerala, India
|Date of Web Publication||28-Jun-2016|
Department of Microbiology, Government Medical College, Thiruvananthapuram, Kerala
Source of Support: None, Conflict of Interest: None
Background: An increase in the prevalence of infections caused by non-albicans Candida (NAC) has been reported from many parts of the world. The increased isolation rates of NAC and a gradual shift in the antifungal susceptibility profile underlines the need for early and accurate diagnosis of Candida infections along with antifungal susceptibility testing. Aim: The aim of this study is to characterise Candida spp. isolated from various clinical samples and determine the antifungal susceptibility pattern. Settings and Design: This study was conducted in the Department of Microbiology, at a tertiary care referral centre, over a period of one year and included 200 Candida spp. Materials and Methods: Candida isolates were characterised by conventional techniques and CHROMagar. Antifungal susceptibility test was performed using disc diffusion method. Clinical details and risk factors were recorded and analysed. Results and Conclusions: Candida albicans was the most common species isolated, followed by Candida tropicalis. The Candida isolates were more susceptible to Amphotericin B than other antifungal agents tested. Diabetes mellitus appeared to be the most common predisposing factor for the Candida infections, followed by indiscriminate drug usage.
Keywords: Antifungal susceptibility testing, Candida albicans, non-albicans Candida, risk factors
|How to cite this article:|
Guru P, Raveendran G. Characterisation and antifungal susceptibility profile of Candida species isolated froma tertiary care hospital. J Acad Clin Microbiol 2016;18:32-5
|How to cite this URL:|
Guru P, Raveendran G. Characterisation and antifungal susceptibility profile of Candida species isolated froma tertiary care hospital. J Acad Clin Microbiol [serial online] 2016 [cited 2020 Feb 18];18:32-5. Available from: http://www.jacmjournal.org/text.asp?2016/18/1/32/184753
| Introduction|| |
Candidiasis is the most common fungal disease in humans. Candida species is endogenous and the disease represents opportunistic infection. The clinical manifestations of the disease are extremely varied, ranging from acute, subacute and chronic to an episodic involvement. It may be localised or may become systemic. They cause diseases with severity ranging from benign to potentially life-threatening infection. The increase in the predisposing conditions in recent years has resulted in a concurrent increase in the number of patients who suffer from candidiasis. Candida albicans (CA) remains the predominant spp. causing over the half of all the yeast infection cases in the world. Increase in the prevalence of yeast infections caused by non-albicans Candida (NAC) has been reported in many parts of the world. Accurate species identification is important for the treatment of the Candida infections as the NAC continues to be increasingly documented with decreased susceptibility to antifungal agents. Hence, this study was undertaken to isolate and speciate Candida from cases where candidiasis was suspected clinically, to determine the antifungal susceptibility, and to analyse the predisposing conditions for candidiasis.
| Materials and Methods|| |
A total of 200 Candida isolates from various clinical specimens were taken up for the study. A detailed clinical history was taken to determine the associated risk factors. The various clinical specimens were collected and processed as per the standard microbiological procedures. The Candida isolates which were obtained were further speciated by the standard protocol for yeast identification which included the following tests: Gram's stain, culture on Sabouraud's dextrose agar, germ tube test, cornmeal agar morphology (Dalmau technique), sugar fermentation test and sugar assimilation test (auxanographic plate method). In addition, CHROMagar (BioMérieux) morphology was also studied.
Antifungal susceptibility test was done using the Clinical Laboratory Standards Institute, 2010 method for antifungal disc diffusion susceptibility for yeasts with approved guideline M44-A. We used the following antifungal discs: Fluconazole (25 µg) (HiMedia), Itraconazole (10 µg) (HiMedia) and Amphotericin B (20 mcg) (HiMedia).
| Results|| |
A total of 200 clinical isolates of Candida from various clinical specimens were processed during the study. The rate of isolation of the Candida species was more in females than in males [Table 1].
[Table 2] shows the age distribution in the culture positive cases. The highest incidence was seen in the age group above 60 years 48 (24%).
[Table 3] shows the various clinical samples from which Candida species were isolated.
[Table 4] shows the distribution of various Candida species among the isolates. CA was the predominant isolate.
[Table 5] shows the distribution of various Candida species among the different samples received.
An analysis of the risk/predisposing factors in patients from whom the Candida species were isolated showed that 45 (22.5%) had underlying diabetes mellitus, 32 (16%) were on long-term multiple antibiotics and 4.5% had immunosuppression due to other causes [Table 6].
CA was isolated in more numbers when compared to NAC in all samples, except from immunosuppressed patients. [Table 7] shows species distribution according to associated risk factors.
All the isolates of Candida were subjected to antifungal susceptibility testing. A total of 196 (98%) isolates were found to be sensitive to Amphotericin B, whereas only 147 (73.5%) were sensitive to Fluconazole [Table 8].
|Table 8: Distribution of isolates according to anti-fungal susceptibility pattern|
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| Discussion|| |
Due to the variable clinical presentation of Candida infections, it becomes very important to identify these pathogens from all the routine culture specimens received at the laboratory irrespective of clinical diagnosis. Candida spp. differ in their antifungal susceptibility and virulence factors. Thus, identification of Candida up to species level along with antifungal susceptibility becomes very essential. Early identification and speciation of Candida is important in selecting appropriate antifungal treatment since resistance to polyenes has been reported in Candida spp., especially Candida tropicalis, Candida glabrata, and CA.
Although candidiasis can occur at all ages, studies by Dalal and Kelkar showed the highest incidence of candidiasis to be in the age group of 21–40 years. These findings were in concurrence with those of our study where the age group of >18 years to <45 years was that which had the highest incidence of candidiasis. This might be because this age group is associated with higher hormonal variation, sexual activity and rates of pregnancy.
Female patients contributed 54.5% and male patients 45.5%. Similar female predominance by noted by Kandhar et al. (61.2%), Dharwad and Saldanha (64%). This could be due to the higher number of samples which were collected from female patients.
In this study, among the 200 isolates, CA (45%) was the major species isolated. A similar prevalence was noted by many other researchers; Price et al. found CA to be the most common isolate. However, we observed that when put together, NAC (55%) are more frequently encountered than CA (45%). This is in agreement with the studies conducted by Chakrabart et al. and Mokaddas et al. ,, These findings seem to suggest that NAC are emerging as important pathogens. The predominant NAC isolated in our tertiary care centre was C. tropicalis.
The association of various risk factors was studied in all the 200 patients. Diabetes mellitus was the most frequently associated risk factor. In this group, the most commonly isolated species was CA. A history of multiple antibiotics usage was the second most frequently associated risk factor (22%). The drugs which were incriminated were mainly antibiotics, corticosteroids and contraceptive pills. Pregnancy was the third most common predisposing factor. In this group, CA was the most common species isolated. Occurrence of candidal vulvovaginitis in pregnant women causes a risk of transmission to new-born infants. Other significant risk factors were immunosuppression, sepsis, preterm/low birth weight and indwelling devices.
The antifungal susceptibility pattern showed that 53 (26.5%) of the Candida isolates were resistant to Fluconazole, 19 (9.5%) were resistant to Itraconazole and 4 (2%) were resistant to Amphotericin B., It was also observed that resistance was more in the NAC group when compared to CA.
| Conclusions|| |
Over the last few decades, fungal infections are increasing at an alarming rate. This is a great challenge to health-care professionals. It is important to monitor the resistance trends and distribution of Candida spp. in the face of increasing usage of potent, broad-spectrum antibacterial agents in hospitals across India. We should develop local guidelines on treatment based on the epidemiology of infection in the Indian subcontinent. Continued surveillance will be important to document changes in epidemiological features of candidiasis and antifungal susceptibilities. Therefore, the description of Candida infections at the species level and research on antifungal sensitivity will be very useful in the treatment and prevent the development of resistance.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]