الفهرس 
TitleOnly 14 pages are availabe for public view
 |  | from | 123 |  |  |
| | | from | 123 | | |
Abstract
Since the 1980s there is raising in the incidence and the diffusion of invasive fungal
infections. The different Candida species are being commensals in all healthy humans and
they have great adaptability to variant host niches. Candida are from the most frequent
fungi that cause nosocomial bloodstream infections. And being a fundamental toll in terms
of prolonged hospital stay, health care costs, morbidity and mortality. Rapid and correct
identification of species enhance the early decision of the most suitable antifungal
treatment and speed up recovery. Although C.albicans is the most frequent species causing
invasive fungal infections, there is an increase in rates of infections by NAC.
The aim of the current study was to identify Candida species isolated from
bloodstream infections using different methods of identification to compare between them,
determine their susceptibilities to different antifungal agents to show the local resistance
profiles, and detect some virulence factors of the isolated Candida species.
This study included fifty Candida species isolated from blood stream infections.
Candida was identified to the species level using three methods of identification
chromagar (HiCrome™ Candida Differential Agar), VITEK 2 compact system and
MALDI-TOF MS.
The most frequent isolate using VITEK 2 compact system was C.albicans; 21 (42%)
followed by C.parasilosis; 14 (28%), C.tropicalis;8 (16%),C.glabrata;4 (8%) and the least
frequent isolates included C.auris, C.kefyr, C.guilliermondii; one isolate each representing
(2%).
The 50 Candida isolates included in the current study were extacted by the formic
acid extraction method, identified by MALDI-TOF and analyzed with Bruker Daltonics.
All Candida isolates tested were identified to the genus level with score ≥1.7. The vast
majority of C.albicans isolates were;20 (90.9%),followed by C.parapsilosis; 9 (75%),
C.tropicalis;6 (60%), (100%)of C.glabrata;4 and the single isolate (100%)of C.kefyr; were
identified to the species level with score >2. Meanwhile, (9.1%) of C.albicans;2, (25%) of
C.parapsilosis;3 (40%) of C.tropicalis;4 and the single isolate (100%) of C.auris were
identified to the genus level with score 1.7-2.0.
On the other hand, chromagar identified only 4 species; C.albicans;21 (42%)
C.parasilosis;18 (36%), C.tropicalis;8 (16%) and the least was C.glabrata;3
(6%).Meanwhile, VITEK 2 compact system identified seven Candida species (C.albicans,
C.parapsilosis, C.tropicalis, C.glabrata, C.auris, C.kefyr, and C. guilliermondii).
There was discrepancy in the results of the three identification methods applied in the
current study (.Referring to VITEK 2 compact system as the gold standard) ; MALDITOF
MS had (100%)correct species identification level with only C.glabrata, C.auris and
C.kefyr. On the other hand, chromagar had (100%) correct species identification level with
only C.albicans and C.tropicalis. C.guilliermondii was only identified by VITEK 2
Summary, Conclusion and Recommendations
63
compact system. There was no statistically significant difference between the result
obtained by the three methods used which may be explained by the small number of
isolates tested .
The Antifungal susceptibilities of 50 Candida isolates were determined by The
VITEK 2 compact system (bioMérieux, Inc., Hazelwood, MO) which is a fully automated
system following the standard technique, according to the manufacturer‟s instructions.
Quality control was done by testing C.krusei ATCC 6258and C.parapsilosis ATCC 22019.
The 50 Candida isolates collected from blood stream infections were sensitive to the tested
antifungal drugs (Fluconazole, Voriconazole, Caspofungin, Micafungin, Amphotericin B,
Flucytosine) except one isolate for each of C.albicans and C.glabrata that both were
resistant to Fluconazole.
In the current study 50 Candida isolates were tested for haemolysin production by
the method described by Manns et al. All the tested Candida species showed moderate
hemolytic activity except Candida parapsilosis (71.42%) showed no hemolytic activity
while only (7.14%) showed moderate hemolytic activity.
This table shows that among the tested C.albicans isolates (52.38%) and (47.62%)
were non biofilm and weak biofilm producers respectively. On the other hand
C.parapsilosis isolates (42.85%), (42.85%) and (14.28%) were non biofilm, weak biofilm
and moderate biofilm producers respectively. While For C.tropicalis isolates (12.5%),
(12.5%), (37.5 %) and (37.5 %) were non biofilm, weak biofilm, moderate biofilm and
strong biofilm producers respectively. And out of the four C.glabrata isolates (50%),
(25%)and (25%) were non biofilm, weak biofilm, and moderate biofilm producers
respectively. (100%) of C.auris isolates were weak biofilm producer. (100%) of each
C.kefyr and C.guilliermondii isolates were moderate biofilm producers.
There was no statistically significant difference in the degree of biofilm formation
between the results of the two techniques used with C.tropicalis, C.glabrata, C.auris,
C.kefyr and C.guilliermondii. Meanwhile, there was statistical significant difference in the
degree of biofilm formation between the results of the two techniques used with C.albicans
and C.parapsilosis.