Evaluation of Candida Colonization in Intensive Care Unit Patients and the Use of Candida Colonization Index

Abstract

Parallel to the developments in the field of diagnosis and treatment, an increase in the incidence of fungal infections and the number of patients who are in the risk group for the development of opportunistic fungal infections have been observed in the recent years. Among the hospitalized patients, those most at risk in terms of fungal infections are intensive care unit (ICU) patients. The rate of Candida colonization of mucous membranes in hospitalized patients may reach to 80%, and this may predispose to the establishment of severe infections especially in patients under risk. The aim of this study was to evaluate the rate of Candida colonization and to use Candida colonization index in the intensive care unit patients in Ankara Training and Research Hospital, Ankara, Turkey. A total of 100 adult patients (46 female, 54 male; age range: 18-93 years, mean age: 65.28 ± 17.53 years) who were hospitalized for ≥ 7 days in the neurology (n= 56), anesthesia-reanimation (n= 24) and neurosurgery (n= 20) intensive care units between September 2008 to February 2009, were included in the study. Throat, nose, skin (axilla), urine, rectal swab cultures and additionally when necessary tracheal aspirates, drain and central vascular catheter cultures were taken weekly from each patient. Candida colonies were identified by using germ tube test, CHROMagar Candida Medium (Becton Dickinson, Germany) and ID 32 C (BioMeriux, France) yeast identification kit. Candida colonization index (CI) was calculated for each patient, and CI was defined as the ratio of the number of culture-positive distinct body sites to the total number of body sites cultured. Patients with CI > 0.2 were considered as Candida colonized. In our study, Candida colonization was found in 42 of 100 (42%) patients, of them 8 were heavily colonized (CI ≥ 0.50), and 34 were slightly colonized (C I < 0.50). The highest Candida colonization was detected in throat, urine and rectal swab samples, while none of the tracheal aspirate samples yielded Candida spp. growth. Invasive Candida infections subsequently developed in 21.4% (9/42) of the colonized patients, namely candidemia in five and Candida associated urinary tract infections in four cases. Our data indicated that, the number of colonized patients were higher in the surgical (anesthesia-reanimation and neurosurgery) intensive care units (p< 0.05), in patients staying in the ICU for longer periods (p= 0.000) and in patients with higher number of application of invasive instruments (p< 0.05) compared to those of non-colonized cases. Additionally Candida colonization emerged more often in patients with bacterial sepsis and in those exposed to broad spectrum antibiotics (p< 0.05). Use of broad spectrum antibiotics in the ICU, length of stay in the ICU and having central venous catheter were found as independent risk factors for Candida colonization. The sensitivity, specificity, positive and negative predictive values of colonization index for the detection of developing Candida infections in colonized patients were estimated as 100%, 64%, 21% and 100%, respectively. In conclusion, Candida colonization and Candida colonization index may be used as useful parameters to predict invasive Candida infections.