Incidence of fungal infections has been arising globally and found most commonly caused by Candida species. Candida species are responsible for causing many health care associated and central line associated infections.1
Nosocomial infection are concerned more with medical device leading to dreadful consequences like systemic infection that could be life taking, also complicated by destruction of internal tissue.2 Mortality rate is 50% in patients of blood stream infection.3
Among Human immunodeficiency virus (HIV) patients and other immunocompromised patients oral candidiasis is very commonly caused by Candida albicans.4 In women it colonizes genital area causing vagina candidiasis leading to vaginal thrush.
Even though researchers have pointed out that Candida might be causative factor for mucositis of digestive tract, part played by catheter in patients with unusal lower number of neutrophils is still not understood in comparison to patients of intensive care unit (ICU).5
The cases of infection caused by Candida albicans have been reduced in number but rate of Non-albicans species have been increased.6
Antifungal resistance by non-albicans Candida provisions the quick, early and accurate identification and is vital because of an increase in evidence of epidemiological shift of causative agents from C.albicans to non-albicans Candida.7
Material and Methods
The study was carried out in the Department of Microbiology, in Tmu Hospital Moradabad.
Total numbers of 806 clinical samples were processed in which 206 isolates were taken for candida. Sample was collected from various ICU’s and various other clinical departments of the hospital. The different clinical specimens like blood, E.T aspirates, BAL fluid, throat swab, urine, high vaginal swab, Foley’s catheter tip and Venous catheters were taken.
Respiratory samples were inoculated on Blood Agar and SDA. Urine samples were inoculated on CLED Agar and incubated at 370 for 24-48 hrs.
The collected blood samples were inoculated into the culture bottle for blood culture and positive blood culture were indicated by change in the color on the screen of BacT ALERT 3D. 8
Positive blood culture were proceeded for subculture and were incubated at 37 0temp for 24-48 hrs .
Colonies have been identified on the basis of colony morphology and culture characteristics. After gram’s staining Speciation and Antifungal sensitivity pattern was done by Vitek-2 system.
Identification & Antifungal Suceptibility Testing
Identification, speciation and antifungal susceptibility of Candida species was done by automated method.
Identification of Candida species was done by VITEK 2 with 2 YST Card & antifungal susceptibility was done with VITEK 2 AST-YSO7 Card. 8
Sample preparation 9
24hr old culture was tested. Cassette of Vitek 2 compact labeled with barcode was selected and the no. of cassette were defined.
In the cassette, polystyrenes tube was placed and 3ml of Vitek saline was taken in these tubes.
After that by using sterile loop the isolated colonies were emusified in Vitek saline. A uniform suspension was made.
Inoculum was checked by Densicheck plus. McFarland standard (Vitek 2.20 YST and Vitek 2 YST Card) was checked by Densichek.
Cards were prepared for inoculation.
Pre-inserted Vitek 2.20 YST Vitek 2 YST Card, were transferred into selected polystyrene tubes from the corresponding suspension.
Then all the prepared inoculums in cassette were loaded into the instrument in filler section.
Loading of sample
Prepared Cassette were loaded into the filler section of instrument, after that door was closed.
The User Interface Screen was pressed and it was completed in 70seconds cycle. Blue indicator light was flashed when the filling cycle was completed. Cassette was removed from the filler section and loaded into the load section within 10 minutes. Barcodes were scanned & checked against the maintain Virtual Cassette electronic work list. Straws were cut and taped up. Finally, Cards were loaded into carousel.
The cassette wastes were discarded and it was indicated by flashing blue arrow on the instrument. The loading was completed.
The samples were obtained from the patients admitted in ICU’s of Hospital. Out of 806, total 206 Candida isolate from various clinical specimen from different ward of intensive Care Unit.
Maximum isolated species were C.albicans 77(37%), followed by C. tropicalis 70(34%), C. parapsilosis 24(12%), C. glabrata 19(9%), C. dubliniensis 12(6%) ,C. krusei 3( 1%), C.african 1(1%).
Infection caused by Candida has been increasing gradually. Candida species normally present as commensal of the human body but capable of causing opportunistic infection especially in immunocompromised individual. 10
Although, infection caused by C. albicans is very common but recently infection of NAC is increasing. NAC species are gaining importance in recent years because they show resistance to antifungal drugs. In our study, percentage of non albicans Candida (62.6%) was higher than Candida albicans (37%). Identical study was conducted by Sundaram M et al9 concluded that NAC (57%) was higher than C.albicans (43%). While in a study conducted by Lerory O et al11 C. albicans (57.0%) were isolated more as compared to Non-albicans Candida.
In our present study albicans isolated was 37% and in NAC most commonly isolated species was C. tropicalis (33.9%) followed by C. parapsilosis (11.6%), C. glabrata (9.2%), C. dubliniensis (5.8%), C. krusei (1.4%) and C.african (0.4%).A study done by Ahmad I et al12 had similar percentage that C.albicans isolated was 36% and in NAC most commonly found species was C. tropicalis (40%) followed by C. glabrata (10%), C. dubliniensis (9%) and C. krusei (2%).
Our study showed that the rate of Candida infection were more in male 67% than in female 36%. This result is comparable with other study conducted by Yashavanth R. at el13 where 62.12% of Candida was isolated in male and 37.87% in female. this is contrast to the study conducted by Kauffman C et al.14 which showed Candida were more isolated in female 54.7% than male 45.3%.
In our study, C.albicans showed 35%, 34%, 22% resistance to fluconazole, voriconazole and Flucytosine but showed least resistance to Micafungin 10%, Caspofungin 10% and 8% to amphotericin-b. More resistance to azole was seen in C.albicans and this was comparable to a study conducted by Rajeevan et al.15
All isolated C. krusei were resistance to fluconazole which was comparable to the study done by Mondal et al.16 C. krusei was 67% susceptible to Caspofungin, Micafungin, amphotericin-b, Flucytosine and only 33% susceptible to voriconazole.
C. parapsilosis showed 100% susceptible to Micafungin, Caspofungin, amphotericin-b and Flucytosine. Only some showed resistance to azole group, 9% to voriconazole and 5% to fluconazole. In contrast Jangla S M et al.17 found 100% sensitivity to azole group, amphotericin-b, Micafungin, Caspofungin, Flucytosine among all Candida species.
C. tropicalis showed 100% susceptibility to Micafungin, amphotericin-b and Caspofungin. But showed 9% resistance to fluconazole & voriconazole, 3% resistance to Flucytosine. C. dubliniensis showed 100% susceptible to Micafungin and 91% susceptible to rest of the antifungal drug used in our study.
Infection caused by Non albicans candida (NAC) species has been increased. C. tropicalis was the most common isolated species. Candida albicans, C.glabrata and C.krusei showed high susceptibility to fluconazole and voriconazole. Amphotericin B, Caspofungin, Micafungin and Flucytosine showed high susceptibility towards other candida species.
Our study concluded that VITEK 2 was more accurate and less time consuming as comparative to conventional methods. Identification of candida species and their antifungal susceptibility are important for the treatment of immunocompromised patients and patient with serious underlying disease.