Candida albicans identification: comparison among nine phenotypic systems and a multiplex PCR

Background. Candida albicans is the most common fungal pathogen isolated from clinical samples and is also the most common yeast species carried as a commensal by healthy individuals although some non-C. albicans species account for an important number of infections. Objectives. To compare nine phenotypic systems for C. albicans identification [API 20C AUX; RapID Yeast Identification panel (RYIP); Vitek2 ID-YST system; chromogenic media, CHROMagar, Oxoid Chromogenic Candida Agar (OCCA), Candida ID2, Candida Identification Agar, CandiSelect 4, and Chromalbicans Agar] with multiplex PCR. Patients/Methods. A collection of 390 yeast strains was obtained by routine isolation from oral and vaginal swabs. All of the yeasts isolated were tested for germ tube formation, and then submitted to a multiplex PCR protocol tested in previous studies, and to nine phenotypical commercial methods, together with the reference ATCC strains. Comparison was limited to the ability of the tests to identify C. albicans. Results. 253 isolates were provisionally identified as C. albicans by germ tube, and their identities were further confirmed with the multiplex PCR. Sensitivity of phenotypical systems ranged from 81.9% (Vitek2) to 87.7% (Candida ID2 e CHROMagar). For specificity, the highest value was 96.8% for Candida ID2, and the lowest value (75.1%) was for Chromalbicans Agar. Conclusions. Although with differences in discriminatory power, the methods tested showed overall acceptable levels of sensitivity and specificity respect to the multiplex PCR; therefore, all could be useful for C. albicans identification where molecular differentiation is not available

Environmental microbial contamination in dental setting: a local experience

ntroduction. Patients and operators are exposed during dental practice to an infective risk, which derives especially from micro- organisms suspended in aerosols. Environmental microbiologi- cal monitoring in dental settings represents a good instrument to detect critical situations. Methods. In order to investigate environmental microbial contami- nation level in a local reality, we analyzed water, air and surfaces samples of a community-based dental facility by using protocol and threshold values proposed in a recent multicenter study carried out by the Italian Society of Hygiene, Preventive Medicine and Public Health (S.It.I.) working group ?Hygiene in Dentistry?. Microbial contamination was assessed in the same room for 4 non-consecu- tive weeks during all the five working days, before and at the end of the daily activity. Air was sampled also during clinical activity, through both active and passive sampling systems. Results. Contamination of water showed a decrease during activ- ities, while a decrease in air contamination was registered only at the end of the day. Passive sampling values resulted more often above threshold values adopted. At the same time, surfaces con- tamination increases at the end of the activity. It seems that in the dental clinic analyzed microbial buildup represents the higher critical element. No differences have been registered among the different days of the week. Discussion. Our study highlights the need to improve disinfection procedures and air treatment systems in the considered environ- ment. Microbiological monitoring could represent an important element to detect the presence of risk factors and to adopt control measures