Candida tropicalis in a Neonatal Intensive Care Unit: Epidemiologic and Molecular Analysis of an Outbreak of Infection with an Uncommon Neonatal Pathogen

Abstract

, two episodes of Candida tropicalis fungemia occurred in the Aristotle University neonatal intensive care unit (ICU). To investigate this uncommon event, a prospective study of fungal colonization and infection was conducted. From December 1998 to December 1999, surveillance cultures of the oral cavities and perinea of the 593 of the 781 neonates admitted to the neonatal ICU who were expected to stay for >7 days were performed. Potential environmental reservoirs and possible risk factors for acquisition of C. tropicalis were searched for. Molecular epidemiologic studies by two methods of restriction fragment length polymorphism analysis and two methods of random amplified polymorphic DNA analysis were performed. Seventy-two neonates were colonized by yeasts (12.1%), of which 30 were colonized by Candida albicans, 17 were colonized by C. tropicalis, and 5 were colonized by Candida parapsilosis. From December 1998 to December 1999, 10 cases of fungemia occurred; 6 were due to C. parapsilosis, 2 were due to C. tropicalis, 1 was due to Candida glabrata, and 1 was due to Trichosporon asahii (12.8/1,000 admissions). Fungemia occurred more frequently in colonized than in noncolonized neonates (P < 0.0001). Genetic analysis of 11 colonization isolates and the two late blood isolates of C. tropicalis demonstrated two genotypes. One blood isolate and nine colonization isolates belonged to a single type. The fungemia/colonization ratio of C. parapsilosis (3/5) was greater than that of C. tropicalis (2/17, P ‫؍‬ 0.05), other non-C. albicans Candida spp. (1/11, P ‫؍‬ 0.02), or C. albicans (0/27, P ‫؍‬ 0.05). Extensive environmental cultures revealed no common source of C. tropicalis or C. parapsilosis. There was neither prophylactic use of azoles nor other risk factors found for acquisition of C. tropicalis except for total parenteral nutrition. A substantial risk of colonization by non-C. albicans Candida spp. in the neonatal ICU may lead to a preponderance of C. tropicalis as a significant cause of neonatal fungemia.Candida spp. are common causes of nosocomial invasive infections in neonatal intensive care units (ICUs). Although Candida albicans has historically been the most frequently isolated species, infections caused by non-C. albicans Candida spp. have been diagnosed with increased frequency in recent years (14,17). In particular, Candida parapsilosis has become the predominant fungal pathogen in many neonatal ICUs (11,14,17). Moreover, recent studies have shown that C. parapsilosis is often a cause of clusters and common-source outbreaks (12, 29).In contrast, little is known about the roles of other non-C. albicans Candida spp. in neonatal ICUs (4). To our knowledge, Candida tropicalis fungemia in neonates has not been adequately described, and the significance of mucocutaneous colonization of neonates by this pathogen remains speculative.Two chronologically related unusual cases of C. tropicalis fungemia that occurred in the Aristotle University neonatal ICU prompted us to initiate a prospective study of fungal co...

Characterization and Antifungal Susceptibility Pattern of Candida SPP . Isolated From Clinical Specimens

“…Several studies have shown that positive culture of C. tropicalis to be highly predictive of subsequent systemic infection. 22 After C. tropicalis and C. albicans, C. glabrata was the third most common Candida spp. isolated (4.2%) which is similar to that of other studies.…”

Use of Quantitative Real-Time PCR To Study the Kinetics of Extracellular DNA Released from Candida albicans , with Implications for Diagnosis of Invasive Candidiasis

“…Organisms and culture were prepared as previously described (19). C. albicans DNA was extracted as described earlier (23). Briefly, an overnight culture of C. albicans was grown on Emmons' modified Sabouraud glucose agar plate (SGA) containing chloramphenicol and gentamicin (Bioworks, Inc., Baltimore, MD).…”

“…Invasive candidiasis remains one of the leading causes of morbidity and mortality in immunocompromised and critically ill patients (1,8,9,15,18,20,23), with Candida albicans infections comprising 45% of all Candida bloodstream infections (10). Since the earliest introduction of PCR for the detection of C. albicans in blood (3,12), this technology has been increasingly refined for molecular detection of deeply invasive candidiasis.…”

Incidence of <em>Candida</em> species colonization in neonatal intensive care unit at Riyadh Hospital, Saudi Arabia

“…This was also suggested by Roilides et al 27 in a molecular epidemiologic study of an outbreak of infection caused by C. tropicalis in NICU. Mendiratta et al 5 reported no samples from NICU or hands of HCW were positive for Candida.…”