Use of random amplified polymorphic DNA as a typing method for Candida albicans in epidemiological surveillance of a burn unit

Abstract

Burn patients are particularly exposed to deep-seated nosocomial infections caused by Candida species. Superficial carriage of C. albicans is a potential source of infection and dissemination, and typing methods could be useful to trace the different isolates. We report the use of random amplified polymorphic DNA to type isolates of C. albicans in the Hôpital Cochin burn unit. This molecular typing method, which is based on PCR with arbitrary short primers, was evaluated on a panel of 32 C. albicans strains isolated from various anatomical sites of unrelated patients, and the strains showed 22 different patterns. Random amplified polymorphic DNA was then used in the epidemiological surveillance of the patients in the burn unit over a 9-month period. Seven patterns were identified among 84 isolates from 18 patients. One pattern (pattern A) corresponding to isolates from 7 of the 18 patients (68% of isolates) predominated throughout the 9-month study, while some strains with other profiles were isolated only once. Some profiles appeared to show a particular geographic pattern within the unit, suggesting transmission from room to room. These results underline the importance of fungal surveillance in such patients and the need to inform nursing staff of measures to prevent the spread of Candida spp. from patient to patient.

Molecular epidemiology ofCandidaspecies isolated from clinical specimens of intensive care unit patients

“…[12][13][14][15][16][17] Many authors have reported that RAPD-PCR could be used to type Candida species with high discriminative power, 20,29 as high as 0.97 in one study in which 84 C. albicans strains isolated from burn unit patients were examined. 30 Becker et al, 21 in their study dealing with C. glabrata, concluded that RAPD-PCR was simple, inexpensive and could be applied to many strains.…”

“…Band patterns of two isolates can be transformed into numerical values such as similarity coefficients. Dice coefficient was the most frequently used one for Candida species in studies reporting similarity coefficients, 11,22,23,30,31 thus we used this coefficient as well. Soll 12 reminds us that no standard evaluation criteria have been validated for the RAPD-PCR test.…”

“…Soll 12 reminds us that no standard evaluation criteria have been validated for the RAPD-PCR test. Some authors used the primer with highest discriminative power, 21,30 while others used more than one primer and combined the results for analysis. 11,22,[32][33][34][35] We preferred this latter method, using several primers.…”

“…12,24 As the use of genotypical methods has increased in recent years, exogenous nosocomial infections have also begun to attract attention, but are still less prevalent than endogenous infections. 23,[30][31][32][33][34][35][36] There are numerous studies investigating the genetic diversity of Candida isolates recovered from ICU patients, and the results about the clonal relationship of the isolates have been varied. Marco et al 23 found crosscontamination between C. albicans isolates recovered from blood cultures of ICU patients, and Arif et al 36 also reported cross-contamination between C. glabrata isolates of ICU patients.…”

A review of molecular techniques to type Candida glabrata isolates

“…21 Random amplification of DNA Random amplification of DNA (RAPD), described by Williams et al [22], is one of the most applied techniques for the survey of the epidemiology of Candida glabrata and other fungi. 23,24 Using random primers of approximately 10 bases, amplicons throughout the genome are targeted and amplified. Amplified products are separated on agarose gel and stained with ethidium bromide.…”