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Ann Saudi Med. 2010 Mar–Apr;
30(2): 101–108, PMCID: PMC2855059
Candidal Colonization, Strain
Diversity, and Antifungal
Susceptibility Among Adult Diabetic
Patients.
Safia A. Al-Attas, Soliman O. Amro.
The purpose of this study was to
investigate oral yeast colonization
(rate and density of acquisition of
Candida
species colonies), strain
diversity, and antifungal
susceptibility in adult diabetics,
and to evaluate the influence of
some local and systemic host factors
on candidal colonization. Oral
candidiasis is a common
opportunistic infection of the oral
cavity caused by an overgrowth of
candidal species, the most common
being
Candida albicans.
Diabetes mellitus (DM) is believed
to be one of the underlying causes
of oral candidiasis, although it is
the subject of some controversy.
Diabetes mellitus, specifically type
2 diabetes, is a major public health
issue. Currently, there is a lack of
reliable evidence on the prevalence
and characteristics of oral fungal
infections in diabetics or the
underlying risk factors associated
with these infections coupled with
diabetes mellitus.
This Saudi
case-control study was conducted on
150 diabetic patients (49 type 1,
101 type 2) and 50 healthy controls.
The diabetic patients were recruited
from a hospital-based diabetic
clinic, on a specific sampling day,
during routine follow-up
appointments. The inclusion criteria
were a diagnosis of either type 1 or
2 diabetes mellitus and an age of 18
years or older. The control group
included age-grouped and sex-matched
healthy volunteers with no history
of diabetes. The investigators
supervised the completion of a
questionnaire developed to collect
information on demographics (age and
gender), medical variables (diabetes
type, duration, and presence of
diabetes-related systemic diseases),
and local factors (denture status,
oral hygiene, and smoking). The
patient's medical records were used
to gather information on diabetes
type and duration, as well as the
presence of diabetes-related
systemic complications.
All study subjects provided three
samples for laboratory testing. Two
salivary samples were collected, one
for salivary flow rate and pH
determination, and the other for
candidal colonization assessment.
The candidal isolates were
identified and tested in vitro for
antifungal susceptibility to
amphotericin B, fluconazole,
nystatin, flucytosine, econazole,
ketoconazole, and miconazole. A
blood sample was used to measure
glycosylated hemoglobin
concentrations in the diabetic
patients, which assessed the
long-term glycemic control of that
patient. For control subjects, the
blood samples were used to measure
the fasting plasma glucose level.
The researchers concluded that
diabetic patients had a higher oral
candidal carriage rate (the
frequency of detecting positive
Candida
growth), but not density,
compared to non-diabetic controls.
Although
C albicans
was the predominant isolate, a
variety of other candidal species,
with less susceptibility to azole
antifungals, were identified in
diabetics. Oral candidal
colonization was significantly
associated with diabetic type,
glycemic control, and salivary pH,
demonstrating a potential role of
these factors in controlling
candidal infections.
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