Investigation of clonal relationship in hospital-associated Candida parapsilosis isolates

We aimed to investigate the clonal relationship and antifungal susceptibility of C. parapsilosis isolated from hospitalized patients and to determine whether it is due to transmission or not and the spread status of resistant isolates.

Between January 2017 and June 2019, totally 277 C parapsilosis isolated from blood, urine and catheter samples of adult or pediatric in-patient (intensive care and service) who applied to Mycology laboratory in our hospital were included in the study. All isolates were identified using conventional methods, API 20 C AUX (Biomerieux, France) semi-automated system and confirmed by MALDI-TOF MS Biotyper Smart (Bruker Daltonik GmbH, Germany). Randomly amplified polymorphic DNA (RAPD) PCR method was used for molecular genotyping of isolates. MIC values for fluconazole, anidulafungin and amphotericin B were determined according to the M27-A3 CLSI broth microdilution reference method guideline.

Seven different band patterns (A-G) were detected in 277 isolates by RAPD PCR method. According to the rank order of the isolates, 170 (61.37%) C, 65 (23.47%) A, 18 (6.50%) G, 11 (3.97%) B, six (2.17%) E, two (0.72%) F and one (0.36%) D patterns were determined. When the band patterns of the isolates were evaluated according to the years, it was detected that C pattern continued between 2017 and 2019 and that all isolates continued to spread only as C pattern in 2019. While 211 (76.17%) of the isolates were resistant to fluconazole (≥ 8 µg/ml), two (0.72%) were resistant to amphotericin B (≥ 2 µg/ml) and two (0.72%) were intermediate to anidulafungin.

It is noteworthy that the spread of the C pattern in C. parapsilosis strains has increased over the years and is the main pattern isolated from the whole hospital. The detection of high fluconazole resistance in C. parapsilosis isolates in our hospital may also be related to the dominant pattern.