José Manuel Aguirre

Point prevalence, microbiology and antifungal susceptibility patterns of oral Candida isolates colonizing or infecting Mexican HIV/AIDS patients and healthy persons.

We have conducted a longitudinal study over a 3-year period to address the point prevalence, microbiological characteristics and antifungal susceptibility patterns of yeast isolates colonizing or infecting the oral cavities of 111 HIV-infected (51 adults, 60 children) and 201 non HIV-infected (109 adults, 92 children) Mexican persons. Regarding the epidemiology of oral candidiasis, Candida albicans was the most frequent species isolated. Seventy-one out of 85 isolates from colonized persons were C. albicans (83.5%), 27 isolates of them were from HIV-infected children and 44 from non HIV-infected patients. Sixty-two isolates belonged to serotype A which was the most prevalent serotype of C. albicans. Non-albicans species (Candida glabrata, Candida tropicalis and Candida parapsilosis, and Saccharomyces cerevisiae) were isolated from 16.5% of colonized patients and from 38.5% patients with candidiasis or Candida-related lesions. There were nine episodes of infection or colonization by at least 2 different yeast species. In the case of HIV/AIDS patients, it was determined that yeast carriage was not associated with the number of CD4+ cells or the viral load, but HAART reduced the prevalence of oral candidiasis. Overall, most patients harbored strains in vitro susceptible to fluconazole, however 10.8% of the yeasts were resistant to one or more azole antifungal agents and 29% were intermediate susceptible to them. On the contrary, 5-fluorocytosine was very active against all isolates tested, and amphotericin B was active against 97.9% of them.

Isolation of Candida dubliniensis in denture stomatitis

OBJECTIVE To describe the isolation of Candida dubliniensis from a patient with denture stomatitis and to compare with the presence of yeasts in the oral cavities of denture wearers. DESIGN One hundred and fifty-two Candida isolates were recovered through oral swabs from denture as well as the underlying mucosa from 100 patients wearing denture. For detection and identification of fungal isolates, standard phenotypic and genotypic methods were used. RESULTS Forty-five of 100 denture wearers suffered from denture stomatitis. Seventy-three Candida isolates were recovered from 38 denture wearers without denture stomatitis. In this group, Candida albicans was the predominant species (58.9%), followed by Candida tropicalis (15.1%), Candida guilliermondii (13.7%), Candida glabrata (9.6%), and Candida parapsilosis (2.7%). Seventy-nine isolates were yielded from 40 patients suffering from denture stomatitis. C. albicans was also the most frequently isolated species (58 isolates, 73.4%), followed by C. glabrata and C. tropicalis (7 isolates each, 8.9%), and Saccharomyces cerevisiae (2 isolates, 2.5%). One isolate was yielded of the following species: Candida famata, Candida krusei, C. parapsilosis and C. guilliermondii. Moreover 1 isolate was phenotypic and genotypic identified as C. dubliniensis genotype 1. CONCLUSIONS C. albicans is the predominant fungal species isolated from denture wearers. C. dubliniensis could be isolated from adults with denture stomatitis.

Gene promoter hypermethylation in oral rinses of leukoplakia patients—a diagnostic and/or prognostic tool?

Leukoplakia is the most frequent oral precancerous lesion and shows a variable rate of malignant transformation. We hypothesised that the detection of molecular alterations, like the promoter hypermethylation of DNA, in oral cytological samples from patients at risk of developing primary or recurrent tumours could be a valuable diagnostic and prognostic tool in the management of these lesions. Two groups of patients with differing risks of developing oral squamous cell carcinoma (OSCC) were analysed. DNA was extracted from the oral rinse of each patient. The methylation status of the p16, p14 and MGMT gene promoters was determined using a methylation-specific polymerase chain reaction (MSP). Methylation of p16 and MGMT was observed in 44 and 56% of the oral samples, respectively. Only 12% of the cases showed p14 methylation. DNA hypermethylation was more frequent in patients with previous OSCC. DNA promoter hypermethylation is frequent during early oral carcinogenesis and even more so in the later stages. MSP using oral rinses is a non-invasive and highly sensitive technique which could be used to monitor patients with precancerous and cancerous oral lesions.

Dental enamel defects in celiac patients.

OBJECTIVE The incidence and distribution of enamel defects among patients with celiac disease were examined. STUDY DESIGN The oral cavity was explored in 137 patients with celiac disease (mean age 16.2 years; age range 5 to 68 years) and in 52 control patients (mean age 19.8 years; age range 5 to 64 years). Permanent dentition enamel defects were recorded, along with their number and locations. The decayed, missing, and filled teeth index rates were also established, and an investigation was made of the human leukocyte antigens among the patients with celiac disease. The results obtained were analyzed with the chi-squared test, statistical significance being regarded for p < or = 0.05. RESULTS Enamel defects were observed in 72 (52.5%) of the patients with celiac disease (52 patients had systematic defects) and in 22 (42.3%) of the control patients (9 patients had systematic defects). Systematic defects were significantly more common in the celiac disease group. In the patients with celiac disease, 72.2% were symmetrical, compared with 40.9% of the defects in the control patients. The incisors were the most frequently affected teeth, the extent of involvement being significantly greater in the celiac disease group. In patients with celiac disease, DR7, DR3, and DQ2 were the most commonly observed human leukocyte antigens. The mean decayed, missing, and filled teeth index rates were 4.8 and 6.2 in the celiac disease group and the control group, respectively. CONCLUSIONS Enamel defects are common among patients with celiac disease. They tend to be bilateral and symmetrical, and they are chronologically distributed. The lesions affect mainly the incisors and the molars. Patients with such characteristics should be evaluated for possible celiac disease.

Oral Candida Isolates Colonizing or Infecting Human Immunodeficiency Virus-Infected and Healthy Persons in Mexico

ABSTRACT Oral yeast carriage was studied in 312 Mexican subjects. Candida albicans was the most frequent species, but other Candida spp. were isolated from 16.5 to 38.5% of patients. Colonization did not correlate with CD4+ number or viral load, but highly active antiretroviral therapy reduced the frequency of candidiasis. Most isolates were susceptible to fluconazole, but 10.8% were resistant to one or more azoles.

Superficial mucocele: report of 4 cases.

Four cases of the lesion first described as superficial mucocele by Eveson in 1988 are reported. All of the lesions developed in adult women; two of the women had concurrent oral lichen planus. The mucoceles were found on the soft palate, the buccal mucosa, and the upper and lower labial mucosa. The etiologic factors and pathogenesis of this lesion are discussed.

Warthin tumor: A new hypothesis concerning its development

OBJECTIVE Warthin tumor is the second most common benign parenchymal salivary neoplasm. The purpose of this study was to evaluate the histopathologic features of Warthin tumor to determine whether a developmental pattern could be identified. STUDY DESIGN Seventy-nine Warthin tumors in 63 patients (62 male and 1 female; average age, 58.62 years) were examined. All cases were histopathologically classified and morphometrically analyzed with an Optomax system to measure the proportions of lymphoid tissue and cystic cavities. RESULTS The predominantly epithelial type (21% of all cases) of Warthin tumor was associated with a mean patient age at diagnosis of 53 years, a mean evolution time of 2.8 months, an average size of 1 cm, and a mean lymphoid component of 10%. In the case of the classical type (61% of all cases), the mean patient age at diagnosis was 58 years, the mean evolution time 9 months, the average size 2.4 cm, and the mean lymphoid component 40%. For the predominantly lymphoid type (18% of all cases), these values were, respectively, 62 years, 11 months, 2.8 cm, and 74%. The mean size of the classical and lymphoid tumors (79% of the Warthin tumors) was significantly greater (p < 0.0001) than the mean size of the epithelial type (21% of the Warthin tumors). A positive correlation between tumor size and evolution time was found. CONCLUSION Our results suggest that the Warthin tumor initially develops as an adenomatous epithelial proliferation followed by lymphocytic infiltration.

Phospholipase and proteinase activities of Candida isolates from denture wearers

The aim of the present study was to characterise phospholipase and proteinase activities of oral Candida isolates from 100 denture wearers and to study the relationship of these activities with denture stomatitis. Of 100 patients studied, 44 suffered from denture stomatitis. Specimens were collected by swabbing the denture and underlying mucosa. Isolates were previously identified by conventional mycological and genotypic methods. The phospholipase and proteinase activities were evaluated by agar plate methods. A total of 152 isolates were recovered from denture and underlying mucosa, including 101 Candida albicans, 18 Candida tropicalis, 14 Candida glabrata, 11 Candida guilliermondii, four Candida parapsilosis, two Saccharomyces cerevisiae and one isolate each of Candida dubliniensis and Candida krusei. Most C. albicans (97%) showed phospholipase activity; furthermore, the unique C. dubliniensis isolate showed a moderate phospholipase activity. The isolation of C. albicans (chi‐square test, P = 0.0016) and phospholipase production by Candida spp. (chi‐square test, P = 0.0213) was found to be significantly associated with denture stomatitis. Proteinase production was observed in <30% of isolates, and it was not related to the presence of denture stomatitis (P = 0.7675). Candida albicans isolates may produce both virulence factors, although the proteinase production was only observed in <30% of the isolates. Phospholipase production was exclusive of C. albicans and C. dubliniensis.

Candida biotypes in patients with oral leukoplakia and lichen planus

Prevalence of yeasts in 35 leukoplakia and 34 oral lichen planus patients was compared with that observed in persons without oral diseases. Serotype and morphotype were determined on Candida albicans isolates. Yeasts were isolated from the oral cavity specimens of 43.7% of the patients. C. albicans (serotype A) was the predominant species (76% in leukoplakia, 88.2% in lichen planus and 60.8% in healthy persons). Sixteen morphotypes were encountered on malt extract agar, being 732, 733, 734, 753 and 754 the most frequently found. Morphotypes SP1N and SP1Y were the most common on Sabouraud-trypheniltetrazolium agar (68.4% of the isolates from leukoplakia and 73.3% from lichen planus, but only 46.6% of the isolates from healthy oral mucosa showed SP1N morphotype). Presence of oral lesions was associated with a marked reduction in the yeast species and C. albicans biotypes, suggesting that C. albicans and particularly some of its biotypes, show a high potential of adaptation to the changes associated with the development of oral leukoplakia and lichen planus.

Evaluation of CHROM-Pal medium for the isolation and direct identification of Candida dubliniensis in primary cultures from the oral cavity.

Candida albicans is the species most frequently isolated from oral specimens, but the recovery of other Candida species such as Candida dubliniensis is increasing. Differentiation of C. dubliniensis from C. albicans requires special tests and both species are misidentified in some studies. CHROM-Pal (CH-P) is a novel chromogenic medium used in our laboratory for differentiation between C. albicans and C. dubliniensis on the basis of colony colour and morphology, and chlamydospore production. The performance of CH-P and CHROMagar Candida (CAC) was compared for primary isolation and presumptive identification of yeasts from oral specimens from human immunodeficiency virus (HIV)-infected and uninfected individuals. The identification of Candida species on both media was compared with two reference identification methods (API ID 32 C and multiplex PCR). A total of 137/205 oral swabs (66.8 %) plated onto CH-P and CAC media were positive by culture and resulted in the growth of 171 isolates of Candida species on CH-P, whilst only 159 isolates grew on CAC. C. albicans was the most frequently isolated species in both groups of patients, followed by Candida parapsilosis in the HIV-negative group, and by C. dubliniensis in the HIV-infected group. The other Candida species isolated were Candida guilliermondii, Candida glabrata, Candida krusei, Candida tropicalis, Candida famata, Candida rugosa, Candida kefyr, Candida pelliculosa and Candida pulcherrima. The sensitivity and specificity for identifying C. albicans, C. krusei, C. tropicalis and C. dubliniensis on CH-P were over 98.5 %, always equal to or higher than those obtained when CAC was used. CH-P is a simple reliable medium for primary isolation and presumptive identification of yeast isolates from oral samples. The ability of CH-P to discriminate between C. dubliniensis and C. albicans was significantly higher (P <0.05) than that of CAC.