Candida species distribution, genotyping and virulence factors of Candida albicans isolated from the oral cavity of kidney transplant recipients of two geographic regions of Brazil

Extracellular hydrolytic enzyme activities and biofilm formation in Candida species isolated from people living with human immunodeficiency virus with oropharyngeal candidiasis at HIV/AIDS clinics in Uganda

BACKGROUND

Commensal oral Candida species can become opportunistic and transition to pathogenic causes of oropharyngeal candidiasis (OPC) in individuals with impaired immunity through ecological cues and the expression of extracellular hydrolytic enzyme activities and biofilm formation.

OBJECTIVE

We evaluated phospholipase, proteinase, hemolysin, esterase, and coagulase enzymatic activities and biofilm formation in Candida species isolated from people living with human immunodeficiency virus (PLHIV) with OPC.

METHODS

Thirty-five Candida isolates from PLHIV with OPC were retrieved from a sample repository and evaluated for phospholipase activity using the egg yolk agar method, proteinase activity using the bovine serum albumin agar method, hemolysin activity using the blood agar plate method, esterase activity using the Tween 80 opacity test medium method, coagulase activity using the classical tube method, and biofilm formation using the microtiter plate assay method in vitro.

RESULTS

A total of 35 Candida isolates obtained from PLHIV with OPC were included in this study, and phospholipase and proteinase activities were detected in 33/35 (94.3 %) and 31/35 (88.6 %) Candida isolates, respectively. Up to 25/35 (71.4 %) of the Candida isolates exhibited biofilm formation, whereas esterase activity was demonstrated in 23/35 (65.7 %) of the Candida isolates. Fewer isolates (21/35, 60 %) produced hemolysin, and coagulase production was the least common virulence activity detected in 18/35 (51.4 %) of the Candida isolates.

CONCLUSION

Phospholipase and proteinase activities were the strongest in oropharyngeal Candida species.

Oral candidiasis in liver transplant patients: species identification and antifungal susceptibility profile

OBJECTIVE

This study aimed to verify oral candidiasis, identify the causative species, and investigate the antifungal susceptibility of yeasts isolated from liver transplant patients.

METHODS

A descriptive analysis of 97 patients who underwent liver transplantation was conducted at a hospital. Two clinical examinations (Collections A and B) of the oral cavity were performed. Oral material was collected from all patients, inoculated in Sabouraud Dextrose Agar, and incubated at 35℃ for 48 hours. Samples were identified by molecular sequencing of the internal trascribed space region of rDNA.

RESULTS

An antifungal susceptibility test with fluconazole, amphotericin B, and micafungin was performed using the Clinical and Laboratory Standards Institute yeast broth microdilution method. Among the patients, 15 presented with oral candidiasis: eight in Collection A and seven in Collection B. The primary type of candidiasis was atrophic, followed by pseudomembranous candidiasis. The most prevalent species was Candida albicans (nine), followed by Candida glabrata (three), Candida tropicalis (two), and Candida dubliniensis (one). Regarding susceptibility to fluconazole, of the 15 samples, 11 were susceptible, three were susceptible in a dose-dependent manner, and one was resistant.

CONCLUSION

The most commonly identified type of candidiasis was atrophic, with C. albicans and C. glabrata being the most prevalent causative species. One fluconazole-resistant isolate each of C. tropicalis and C. albicans were identified.

In Vitro Evaluation of the Virulence Attributes of Oropharyngeal Candida Species Isolated from People Living with Human Immunodeficiency Virus with Oropharyngeal Candidiasis on Antiretroviral Therapy

Background

Oropharyngeal Candida species are part commensal microflora in the the oral cavity of health individuals. Commensal Candida species can become opportunist and transition to pathogenic causes of oropharyngeal candidiasis (OPC) in individuals with impaired immunity through ecological cues and expression of virulence factors. Limited studies have evaluated virulence attributes of oropharyngeal Candida species among people living with human immunodeficiency virus (PLHIV) with OPC on antiretroviral therapy (ART) in Uganda.

Objective

Evaluation of the Virulence Attributes of Oropharyngeal Candida Species Isolated from People Living with Human Immunodeficiency Virus with Oropharyngeal Candidiasis on Antiretroviral Therapy.

Methods

Thirty-five (35) Candida isolates from PLHIV with OPC on ART were retrieved from sample repository and evaluated for phospholipase activity using the egg yolk agar method, proteinase activity using the bovine serum albumin agar method, hemolysin activity using the blood agar plate method, esterase activity using the Tween 80 opacity test medium method, coagulase activity using the classical tube method and biofilm formation using the microtiter plate assay method in vitro.

Results

Phospholipase and proteinase activities were detected in 33/35 (94.3%) and 31/35 (88.6%) of the strains, respectively. Up to 25/35 (71.4%) of the strains exhibited biofilm formation while esterase activity was demonstrated in 23/35 (65.7%) of the strains. Fewer isolates 21/35 (60%) of the strains produced hemolysin and coagulase production was the least virulence activity detected in 18/35 (51.4%).

Conclusion

Phospholipase and proteinase activities were the strongest virulence attributes of oropharyngeal Candida species.

Assessment of species distribution and virulence factors of oral fungal carriage among hospitalized patients with COVID-19: a case-control study

Background

The COVID-19 pandemic highlighted the need to study oral fungal carriage and its potential impact. In oral fungal environments, factors like changes in respiratory epithelium, increased pathogen attachment, local inflammation, and virulence factors could influence COVID-19 severity. The authors conducted a study to explore oral fungal carriage in COVID-19 patients and compare it to a healthy control group.

Methods

The authors executed a case-control investigation including 144 COVID-19 patients and an equivalent number of 144 healthy controls. The matching criteria encompassed age, sex, body mass index, and the history of antibiotic and antiviral medication intake. This research was performed over a span of 12 months from May 2021 to May 2022. The mouth area was sampled with a cotton-tipped swab. Subsequently, all the samples underwent fungal culture and PCR-sequencing procedures.

Results

In COVID-19 patients, oral fungal carriage was three times higher compared to healthy controls. Candida was the exclusive genus found in both groups, with Candida albicans being the most frequently isolated species (90.79%). Among COVID-19 patients, Candida species showed significantly higher esterase, proteinase, and hemolysin activity compared to healthy individuals. Both groups exhibited elevated levels of C. albicans virulence factors compared to non-albicans species.

Conclusions

It is crucial to understand the way that virulence factors of oral fungal carriage act in COVID-19 patients in order to come up with novel antifungal medications, identify the contributing factors to drug resistance, and manage clinical outcomes.

Genotyping of Candida albicans and Comparison of its Antifungal Resistance Pattern in the South Indian Region

Recent studies have documented an increase in the incidence of antifungal resistance in newly emerging species closely related to C. albicans, and the coexistence of genotypic variants. Hence, an application of PCR-based molecular typing is crucial in identifying these fungi. Our study used molecular methods to characterize the latest genotypic subgroups of C. albicans and analysed if there was a relationship between the genotypes and the antifungal resistance pattern. The study was conducted in JSS Hospital, Mysuru, Karnataka between July 2018 and December 2020. A total of 1427 Candida species were isolated from clinical samples. Candida albicans were isolated and confirmed using Germ tube test, ID VITEK 2 and PCR (ITS primer). DNA extraction was done using the Hi-Media Yeast DNA Extraction Kit. The amplified products were analysed using Agarose gel electrophoresis (2%). Among 1427 Candida species, 282 were Candida albicans. The following resistance was exhibited to major antifungals – Caspofungin (3.5%), Amphotericin B (1.4%), flucytosine (2.8%) Fluconazole (6%) Micafungin (2.8%) Voriconazole (3.1%) and all were sensitive to miconazole. ABC genotyping showed Genotype A (450 bp) predominant (87.58%) followed by genotype B (840bp) (9.92 %) and genotype C (450bp and 840 bp) (0.2%). Genotype D and E were not observed. Our study showed the growing antifungal resistance in clinical isolates. Genotype A was predominant in South Karnataka region followed by Genotype B and C. There was no correlation between genotyping and antifungal resistance. However, a study with greater number of samples from diverse geographical locations may give more insight.

Pediatric candiduria, epidemiology, genotype distribution and virulence factors of Candida albicans

The presence of Candida species in urine may be due to colonization of this species in the bladder, urinary catheter, and perineum. Candida albicans has been the most commonly isolated from urine samples in patients with candiduria. Several virulence factors include adhesion to host cells, secreted extracellular enzymes, phenotype switching, and biofilm formation are contributing to the pathogenicity of C. albicans. ABC genotyping is the method based on the determination of 25s rDNA and C. albicans is divided into four genotypes include A, B, C, and E. We aimed to identify Candida species from pediatrics and evaluate extracellular enzyme activities, phenotype switching, biofilm formation, and genotyping in isolates. Urine samples collected, cultured, and yielded yeasts were identified. Phenotype switching, biofilm formation, enzymatic patterns, and genotyping of 50 isolates of C. albicans were evaluated. The Genotyping pattern was compared with extracellular enzymes, biofilm formation, and phenotype switching pattern. 16.2% of urine cultures were positive for the different Candida species. The most common species was C. albicans, followed by C. glabrata. Out of 50 isolates of C. albicans, 72% and 28% isolates were recognized as genotypes A and C. All isolates were produced extracellular enzymes and biofilm formation. In conclusion, candiduria with high colony counts is still a challenge in Iranian pediatrics. Genotype A was the predominant genotype among C. albicans strains. There is a statistical difference between esterase and genotypes of C and A C. albicans.

Genetic diversity assessed using PFGE, MLP and MLST in Candida spp. candidemia isolates obtained from a Brazilian hospital

Candida spp. are the main causative agents of invasive fungal infections in immunocompromised patients. Candidemia has attributable mortality rates of 15 to 35% and increases hospitalisation time and costs, thus making this disease a public health concern. This study aimed to use pulsed-field gel electrophoresis (PFGE), microsatellite length polymorphism (MLP) and multilocus sequence typing (MLST) to analyse the genetic relationships among 65 Candida spp. bloodstream isolates, including 35 Candida albicans, 15 Candida glabrata and 15 Candida tropicalis isolates, all of which were obtained from patients in a Brazilian hospital. Moreover, patient clinical data were assessed. All techniques resulted in high discriminatory indexes. C. albicans and C. tropicalis isolates showed high genetic variability, while C. glabrata isolates had relatively low genetic variability. Moreover, a cluster of C. glabrata isolates was identified in a hospital unit. New MLST sequence types, diploid sequence types and alleles are described. Relationships were not observed between the molecular typing results and clinical characteristics. The molecular typing of clinical strains increases our understanding of candidemia epidemiology and promotes the development of strategies that can reduce the incidence of this disease. Moreover, this study is the first to combine these techniques to genotype these three species in Brazil.

Genotypic diversity and antifungal susceptibility pattern of Candida albicans species isolated from hospitalized paediatric patients with urinary tract infection in Iran

AIMS

The present study aimed to determine the microsatellite length polymorphism (MLP) genotypic patterns and antifungal susceptibility profiles of Candida albicans isolated from patients with candiduria.

METHODS AND RESULTS

DNA of 50 C. albicans isolates was used for molecular identification based on the ITS₁ -5.8s-ITS₂ region. MLP assays were performed to amplify three loci (EF3, CDC3 and HIS3), and PCR products were used for fragment analysis. Antifungal susceptibility tests were performed according to CLSI M27 4th ed guidelines. In all, 38 different genotypes were detected with the three polymorphic loci among C. albicans isolates, and only one genotype was homozygous. In comparison to other countries, our genotypes were divided into three clusters, two of which were linked to France and a third of which was linked to Austria. The genetic structures of the 50 C. albicans isolates revealed varied heterozygosity and significant Hardy-Weinberg equilibrium at the EF3 locus. Only one (2%) and four (8%) of isolates showed resistance to fluconazole and itraconazole, respectively. In C. albicans genotype G25, one (2%) of the isolates showed cross-resistance and non-wild-type resistance to posaconazole, itraconazole and fluconazole.

CONCLUSION

MLP typing is a useful tool to analyse the genetic structure of C. albicans isolates. High genetic diversity (38 genotypes) was detected in the isolates tested here. Compared to isolates in other countries, the ones from our patients had a clear relationship with French and Austrian isolates.

SIGNIFICANCE AND IMPACT OF THE STUDY

Iranian isolates of C. albicans have a distinct genotype and show similarities only with French and Austrian isolates.

Prevalence, virulence and antifungal activity of C. albicans isolated from infected root canals

Background

There is limited data on the prevalence of Candida species in infected root canal systems of human teeth. We attempted to investigate the prevalence, genotype, virulence and the antifungal susceptibility of Candida albicans isolated from infected root canals of patients with primary and post-treatment infections in a UAE population.

Methods

Microbiological samples from 71 subjects with infected root canals were aseptically collected, and cultured on Sabouraud dextrose agar, and C. albicans was identified using multiplex polymerase chain reaction, and the isolates were further subtyped using ABC genotyping system. Their relative virulence was compared using further four archival samples of endodontic origin from another geographical region, and four more salivary isolates, as controls. The virulence attributes compared were biofilm formation, and production of phospholipase and haemolysin, and the susceptibility to nystatin, amphotericin B, ketoconazole, and fluoconazole was also tested.

Results

4 out of 71 samples (5.6%) yielded Candida species. On analysis of variance among the groups, the intracanal isolates, mainly Genotype A, possessed a high degree of phospholipase and haemolysin activity (p < 0.05). The UAE and Finland isolates were stronger biofilm formers and had superior phospholipase production capacity compared with the salivary isolates. All isolates were sensitive to the antifungal chemicals used. The salivary isolates were more sensitive to fluoconazole compared to other groups (p < 0.05).

Conclusion

The prevalence of C. albicans in infected root canals of patients attending a dental hospital in UAE is low. The strains isolated were good biofilm formers, possessed strong phospholipase and haemolysin activity and were mostly of the genotype A. The fact that the root canal isolates possessed significant hydrolase activity, imply that they are equipped with virulence attributes necessary for survival within a harsh intracanal ecosystem.

Antifungal susceptibility and virulence profile of candida isolates from abnormal vaginal discharge of women from southern India

OBJECTIVE

Vaginal candidiasis is the most common opportunistic fungal infection, largely associated with a woman's psychological and economic status. Recently, the rate of disease progression has increased extensively; however, region-specific studies are very limited. This study aimed to understand variation in hydrolytic activities and antifungal susceptibility of Candida isolates from vaginal discharge.

STUDY DESIGN

The present study was aimed to understand the variation of hydrolytic activities and antifungal susceptibility of Candida isolates from vaginal discharge.

RESULTS

In total, 34 different Candida isolates were collected: C. albicans (n = 17; 50 %), C. glabrata (n = 6; 17.64 %), C. tropicalis (n = 4; 11.76 %) and C. parapsilosis (n = 7; 20.58 %). All isolates were primarily identified and confirmed by basic microbiological methods followed by the VITEK-2 system. Antifungal susceptibility of the isolates were evaluated using yeast antifungal susceptibility testing cards. The isolates of C. albicans, C. glabrata, C. tropicalis and C. parapsilosis were 100 % susceptible to amphotericin B. The non-albicans isolates presented 100 % of proteolytic and lipolytic activity compared with C. albicans. Eight (47.06 %) C. albicans isolates showed positive esterase activity (Pz<1), whereas nine (52.94 %) were negative to esterase (Pz = 1). Of the 34 Candida isolates, 28 (82.35 %) were found to be moderate-to-strong biofilm producers: 14 C. albicans, three C. glabrata, six C. parapsilosis and five C. tropicalis.

CONCLUSION

This study clarified the antifungal susceptibility and virulence behaviour of Candida isolates; this will be of use in the selection of antifungal agents for Candida prophylaxis.

Site-Specific Profiling of the Dental Mycobiome Reveals Strong Taxonomic Shifts during Progression of Early-Childhood Caries

Dental caries is one of the most common diseases worldwide. Bacteria and fungi are both commensals in the oral cavity; however, most research regarding caries has focused on bacterial impacts. The oral fungal mycobiome associated with caries is not well characterized, and its role in disease is unclear. ITS1 amplicon sequencing was used to generate taxonomic profiles from site-specific supragingival plaque samples (n = 82) obtained from 33 children with different caries status. Children were either caries free (CF), caries active with enamel lesions (CAE), or caries active with dentin lesions (CA). Plaque samples were collected from caries-free surfaces (PF) and from enamel (PE) and dentin (PD) lesions. Taxonomic profiles representing the different categorizations (CF-PF, CAE-PF, CAE-PE, CA-PF, CA-PE, and CA-PD) were used to characterize the mycobiome and its change through disease progression. A total of 139 fungal species were identified. Candida albicans was the most abundant species, followed by Candida dubliniensis We found that severely progressed plaque communities (CA-PD) were significantly different from healthy plaque communities (CF-PF). A total of 32 taxa were differentially abundant across the plaque categories. C. albicans, C. dubliniensis, Nigrospora oryzae, and an unclassified Microdochium sp. were correlated with caries, whereas 12 other taxa were correlated with health. C. dubliniensis increased steadily as caries progressed, suggesting that C. dubliniensis may play an important role in caries pathogenicity. In contrast, four health-associated fungal taxa have the potential to antagonize the cariogen Streptococcus mutans via xylitol production, suggesting a possible fungal mechanism that could contribute to maintenance of dental health.IMPORTANCE Early-childhood caries is one of the most prevalent diseases in children worldwide and, while preventable, remains a global public health concern. Untreated cavities are painful and expensive and can lead to tooth loss and a lower quality of life. Caries are driven by acid production via microbial fermentation of dietary carbohydrates, resulting in enamel erosion. While caries is a well-studied disease, most research has focused on bacterial impacts, even though fungi are commensal organisms living within the plaque biofilm. There is very little known about how fungi impact caries pathogenicity. The elucidation of fungal taxa involved in caries disease progression is necessary for a more holistic view of the human oral microbiome. Data from this study will improve our understanding of how the fungal community changes as disease progresses and provide insight into the complex etiology of dental caries, which is necessary for the development of treatment plans and preventative measures.

Virulence and antifungal susceptibility of microsatellite genotypes of Candida albicans from superficial and deep locations

A set of 185 strains of Candida albicans from patients with vulvovaginal candidiasis (VVC) and from non‐VVC clinical sources in southwest China was analysed. Strains were subjected to genotyping using CAI microsatellite typing and amplification of an intron‐containing region of the 25S rRNA gene. Microsatellite genotypes of strains from non‐VVC sources showed high polymorphism, whereas those of VVC were dominated by few, closely similar genotypes. However, among non‐VVC strains, two genotypes were particularly prevalent in patients with lung cancer. 25S rDNA genotype A was dominant in VVC sources (86.7%), whereas genotypes A, B, and C were rather evenly distributed among non‐VVC sources; known genotypes D and E were not found. In an experimental mouse model, isolates from lung cancer and AIDS patients proved to have higher virulence than VVC strains. Among 156 mice infected with C. albicans, 19 developed non‐invasive urothelial carcinoma. No correlation could be established between parameters of virulence, source of infection, and incidence of carcinoma. C. albicans strains from VVC were less susceptible to itraconazole than the strains from non‐VVC sources, whereas there was small difference in antifungal susceptibility between different 25S rDNA genotypes of C. albicans tested against amphotericin B, itraconazole, fluconazole, and flucytosine.

Genotype comparison of Candida albicans isolates from different clinical samples

Background: Fungal infections are a health issue paradoxically fuelled by the developments in medical care. Objectives: Our study is an investigation on the correlation between the infection site and the genotypes of Candida albicans strains isolated from Romanian patients. Methods: A total number of 301 isolates from different clinical sites were investigated in terms of genotype determination. Results: The isolates were clustered in three groups according to their genotype: 55.81% showed genotype A, 14.62% genotype B, and 29.57% genotype C. Conclusions: No significant correlation was found between the genotype and the infection site, but a significant correlation was found between genotype C and isolates from HIV patients proving that C. albicans pathogenicity probably relies on factors related to the host.

Isolation of pathogenic Candida species from oral cavity of postpartum females, and its association with obstetric and dental problems

OBJECTIVE

The aim of the current study was to investigate pathogenic Candida spp. Colonization in oral cavity of postpartum females and its association with adverse pregnancy outcomes (APOs) and dental issues.

METHODS

Saliva samples and clinico-demographic data were collected from 267 postpartum females along with 54 non-pregnant females (Jan 2016-March 2018). Isolation of Candida was carried out by using standard microbiological methods and different virulence factors (Esterase activity, phospholipase activity and biofilm formation) were evaluated.

RESULTS

Candidacolonization was high in postpartum females (p<0.001, OR = 4.28). This colonization was not significant among females with APOs, however, one to three folds risk was seen with different obstetric and dental factors. High esterase activity was seen among Candida isolates from postpartum females in comparison to control group (p = 0.01). Phospholipase activity of C.albicans isolates from this group was also high (p = 0.001). Majority of the Candida isolates (66.87%) from postpartum females were biofilm formers. Increase in antifungal activity was seen among isolates from postpartum females, with 85% isolates resistant to Fluconazole and Voriconazole (p<0.001) and Amphotericin B resistance was present in 64.38% isolates (p<0.001).

CONCLUSION

Postpartum females are more susceptible to oral Candida colonization, which exhibit enhanced virulence characteristics and its carriage are associated with increased risk for development of APOs and dental problems.

Virulence factors of Candida species from the oral mucosa and prostheses of elderly people from a riverside community in the Amazon state, Brazil

Abstract Introduction Candida albicans is the yeast most commonly affecting the oral cavity, sometimes causing infection. However, several factors may be associated with the onset of candidiasis, which may be related not only to the hygiene and health of individuals, but also to the pathogenicity of these microorganisms. Objective To evaluate the virulence factors of Candida yeasts isolated from the oral mucosa of elderly people living in the “Comunidade Lago do Limão”, municipality of Iranduba, Amazonas state, Brazil. Material and method Testes were performed to assess the production of urease, proteinase, phospholipase and hemolysin. Statistical analysis used the Fisher's exact test and the Chi-squared test. Result Prevalence of non-albicans species was observed. As for virulence factors, all isolates were negative ureases, and there was prevalence of very strong proteinase production, whereas most isolates did not produce this enzyme in the phospholipase test. All yeasts analyzed presented hemolysin production, with grade IV hemolysis as the most prevalent. There was no statistically significant difference between the virulence of isolates from the oral cavity and the prostheses of the elderly analyzed. Conclusion Several virulence factors may present with high intensity in the presence of oral microbiota changes. In addition, non-albicans species present number of virulence factors similar to that of C. albicans, with high pathogenicity. This study allows a better analysis of candidiasis prevention strategies aiming to promote improvement in the health and quality of life for the elderly.

Cariogenicity of Candida albicans of distinct genotypes among 3-5-year-old Uygur children in Kashgar, China- a case-control study

Background

In recent years, the opportunistic fungus C.albicans has been linked to ECC.It is important to investigate the relationship between the distribution of C.albicans and early childhood caries (ECC) in 3–5-year-old Uygur and Han children in Kashgar, and the role of C.albicans of distinct genotypes in caries.

Methods

Two hundred fifty-six Uygur and 141 Han children were enrolled in the study. The identified C.albicans isolates were genotyped based on 25S rDNA Polymerase Chain Reaction(PCR) amplification, and their acidogenicity, aciduricity, and adhesiveness were examined. Moreover, secreted aspartic protease (Sap) activity and SAP1–5 transcriptional levels were compared in the ECC and caries-free (CF) groups of Uygur children.

Results

C.albicans detection rate was significantly higher in Uygur children than in Han children (44. 5% vs. 31. 2%; χ2= 6.739, P = 0.009);the A genotype was dominant in Uygur and Han children with ECC, the C genotype was dominant in Uygur CF children(P = 0.022). C.albicans acidogenicity and growth were more pronounced in the Uygur ECC group than in CF group, especially at pH 4.0 and 4. 5(pH 4.0, P = 0.012; pH 4. 5, P = 0.029); the average ratios of glass-wall adhesion and the Sap activity was higher in ECC group than in CF group(P < 0.01), and SAP2(P < 0.001) and SAP5(P = 0.001) were expressed more robustly in ECC group.

Conclusions

The strong acidogenicity and aciduricity, Sap activity, and high SAP2 and SAP5 expression might be closely associated with ECC. C.albicans potentially plays a key role in the progression of caries, which most readily affects genotype A carriers and could be attributed to person-to-person environmental variation.

Buccal Bullfrog (Rana catesbeiana Shaw) Oil Emulsion: A Mucoadhesive System Intended for Treatment of Oral Candidiasis

Oral candidiasis (OC) is an infectious disease caused by microorganisms of the genus Candida, leading to lesions in the buccal cavity. Its treatment consists of the administration of topical or systemic antifungal agents, which may compromise the patient compliance due to its side effects, highlighting the need for alternative treatments. In this scenario, bullfrog oil, an animal oil composed of a pool of saturated and unsaturated fatty acids, is introduced as a potential antifungal raw material. Thus, the aim of this work was to produce a mucoadhesive emulsified system able to deliver the bullfrog oil in the buccal cavity to treat the OC. The emulsion was produced and characterized by visual inspection, droplet size, polydispersity index (PdI), and zeta potential over the course of 60 days. In addition, its mucoadhesive ability was evaluated using an in vitro mucin model. The antifungal activity, evaluated by the broth microdilution assay and the biocompatibility, performed against human erythrocytes, were also carried out. The emulsion showed a droplet size of 320.79 ± 35.60 nm, a PdI of 0.49 ± 0.08, and a zeta potential of -38.53 ± 6.23 mV, with no significant changes over 60 days. The mucoadhesive properties of the system was improved by the use of pharmaceutical excipients. The antifungal activity showed that the bullfrog oil and the emulsion were able to inhibit the growth of different Candida species. Furthermore, the emulsion showed no significant hemolytic effect. Overall, the system showed suitable physicochemical characteristics and biocompatibility, with substantial in vitro antifungal activity, suggesting that this system can be further investigated for OC treatment.

Genetic diversity of the Hwp1 gene and HIS3, EF3, CDC3 microsatellites and antifungal susceptibility profiles of Candida albicans isolates from Yaoundé HIV-infected patients

The molecular epidemiology and the antifungal susceptibility profiles of Candida albicans are scarce in Cameroon. Authors studied the genetic diversity and the antifungal susceptibility of C. albicans isolates from Yaoundé HIV-infected patients. Clinical isolates were obtained by mycological diagnosis of oropharyngeal swabs, stools, urine, and vaginal swabs from patients. C. albicans isolates were confirmed by the Light cycler real-time PCR of the ITS1 region of the 5.8s ribosomal DNA. The ABC genotypes and the Hwp1 gene amplification were carried out with specific primers. Microsatellite length polymorphism of HIS3, CDC3, and EF3 microsatellites was analysed. The antifungal susceptibility testing was carried out by the CLSI broth microdilution M27-A3 and M27-S4 protocols. The minimal inhibitory concentration (MIC) results were interpreted according to updated clinical breakpoints (CBPs) recommended by the CLSI or epidemiological cut-off values (ECVs). One hundred and thirteen (113) isolates were obtained from the analysis of 1218 samples. The ABC genotyping showed 79 (69.91%) genotype A, 24 (21.23%) genotype B, and 10 (8.84%) genotype C. The Hwp1 gene amplification provided a newly observed genetic polymorphism, named H and 5 genotypes described (H1-H5). The microsatellite analysis generated 65 molecular types. All the isolates were susceptible to amphotericin B (MIC ≤ 1 μg/ml); 79.64% of isolates were wild type to itraconazole (MIC ≤ 0.12 μg/ml); and 86.72% of isolates were susceptible to fluconazole (MIC ≤ 2 μg/ml). These results highlight the important genetic diversity of C. albicans isolates among Yaoundé HIV-infected patients and bring clues for the comprehension of the molecular epidemiology of the yeast in Cameroon.

Presence of Candida spp. and candidiasis in liver transplant patients

BACKGROUND

Candidiasis is the most common opportunistic fungal infection of the oral cavity caused by fungi of the genus Candida and usually associated with immunosuppressed individuals.

OBJECTIVES

To evaluate the presence of oral candidiasis and identify the presence of Candida spp. in liver transplant recipients and assess the association between the presence of the fungus and sociodemographic variables, dietary habits and environmental exposure.

METHODS

A cross-sectional study was performed with 49 patients who had undergone liver transplants at Hospital São Vicente de Paulo in Passo Fundo - RS. Patient information was collected to obtain sociodemographic data, eating habits and environmental exposure. Fungal infections were screened by oral clinical examination and the presence of Candida spp by the collection of oral samples with a sterile swab, seeded in Sabouraud Dextrose Agar, incubated at 25°C and observed at 48 hours. To identify Candida albicans, the germ tube test was performed.

RESULTS

In 49 patient samples, 39% had the yeast of the genus Candida isolated and, of these patients, 12% had candidiasis, 66% of atrophic type and 34% pseudomembranous. Eleven yeast species were (58%) Candida non-albicans and eight (42%) Candida albicans.

STUDY LIMITATIONS

The present study presents as a limitation the inclusion of patients in different stages of immunosuppression.

CONCLUSION

The high incidence of Candida non-albicans in the oral cavity of transplant patients with a long period of transplantation is warning to a more effective control of the health of these individuals, especially those with older age.

An Update on Candida tropicalis Based on Basic and Clinical Approaches

Candida tropicalis has emerged as one of the most important Candida species. It has been widely considered the second most virulent Candida species, only preceded by C. albicans. Besides, this species has been recognized as a very strong biofilm producer, surpassing C. albicans in most of the studies. In addition, it produces a wide range of other virulence factors, including: adhesion to buccal epithelial and endothelial cells; the secretion of lytic enzymes, such as proteinases, phospholipases, and hemolysins, bud-to-hyphae transition (also called morphogenesis) and the phenomenon called phenotypic switching. This is a species very closely related to C. albicans and has been easily identified with both phenotypic and molecular methods. In addition, no cryptic sibling species were yet described in the literature, what is contradictory to some other medically important Candida species. C. tropicalis is a clinically relevant species and may be the second or third etiological agent of candidemia, specifically in Latin American countries and Asia. Antifungal resistance to the azoles, polyenes, and echinocandins has already been described. Apart from all these characteristics, C. tropicalis has been considered an osmotolerant microorganism and this ability to survive to high salt concentration may be important for fungal persistence in saline environments. This physiological characteristic makes this species suitable for use in biotechnology processes. Here we describe an update of C. tropicalis, focusing on all these previously mentioned subjects.

The Activities of Adhesion and Biofilm Formation by Candida tropicalis Clinical Isolates Display Significant Correlation with Its Multilocus Sequence Typing

Adhesion and biofilm formation, which can occur on abiotic and biotic surfaces, are key components in Candida pathogenicity. The aims of this study were to infer about the C. tropicalis clinical isolates ability to adhere and form biofilm on abiotic and biotic surfaces and to correlate that with the multilocus sequence typing and other virulence factors. Adhesion and biofilm formation were measured in 68 C. tropicalis isolates from 3 hospitals in China on abiotic (polystyrene) and biotic (human urinary bladder epithelial cell) surfaces by crystal violet assay and 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide reduction assay. In our study, almost all C. tropicalis isolates could adhere and produce biofilm on abiotic and biotic surfaces in a strain-dependent manner. The isolates from blood showed relatively lower adhesion and biofilm capacity on polystyrene surface, but had strong secreted aspartyl proteinase activity. Moreover, significant differences were found among MLST groups for adhesion and biofilm capacity. C. tropicalis in multilocus sequence typing group5 and group6 showed high adhesion and biofilm, while isolates in group1 exhibited low adhesion and biofilm formation. Overall, it is important to note that C. tropicalis isolates adhere to and produce biofilm on abiotic and biotic surfaces with strain specificity. These data will play an important role in subsequent research on the pathogenesis of C. tropicalis.

Antimicrobial Activity of Three Lamiaceae Essential Oils Against Common Oral Pathogens

Chemical composition, antimicrobial and cytotoxic activities of commercial essential oils’ samples from the aerial plant parts of H. officinalis, R. officinalis and S. officinalis were investigated. Analyses by GC-FID and GC-MS confirmed 52 oil components. The major constituent of the H. officinalis oil was cis-pinocamphone (34.4%), followed by transpinocamphone (23.3%), and β-pinene (11.3%). Analysis of R. officinalis oil revealed 1.8-cineol as a major constituent (43.8%), as well as transpinocamphone (12.5%), α-pinene (11.5%) and β-pinene (8.2%). The most dominant constituent of S. officinalis oil was cis-thujone (32.7%), in addition to camphor (17.2%), 1.8-cineol (10.1%), α-pinene (8.6%), transthujone (7.7%) and camphene (7.3%). The essential oil antimicrobial activity assay was performed by the use of microdilution method against oral Candida spp. and bacteria, the major causative agents of a number of human oral disorders; all of them were susceptible to tested concentrations of H. officinalis, R. officinalis and S. officinalis essential oils, although the oil of S. officinalis exhibited the lowest antimicrobial potential. The results obtained in this study encourage use of investigated essential oils from Lamiaceae family in development of safe natural agents for prevention and/ or alternative therapy of human oral diseases. However, a special care during development of an effective natural preparation is required.

Reliability of the agar based method to assess the production of degradative enzymes in clinical isolates of Candida albicans

The aim of this study was to establish a reproducible protocol using the methodology of hyaline zones around the colonies on specific agar plates for phospholipase and proteinase production. This was an in vitro double-blind experiment, in which the dependent variables were the enzymatic activity measurements (Pz) for the production of phospholipase (Pz-ph) and the production of secreted aspartyl proteinases (Pz-sap). Three independent variables give rise to different measurement protocols. All measurements were carried out at two different moments by four examiners (E1, E2, E3, and E4). The minimum sample size was 30 Candida albicans clinical isolates. Specific agar plates for phospholipase and SAPs production were prepared according the literature. The intra-and inter-examiner reproducibility for each protocol was estimated using the Intraclass Correlation Coefficient (ICC) and its confidence interval (95% CI). Based on the results obtained for both phospholipase and SAPs, there appears to be no consensus on the protocol chosen for each particular examiner. Measuring the colonies in triplicate may be the main factor associated with the increase in measurement accuracy and should therefore take precedence over measuring only one colony. When only one examiner is responsible for taking measurements, a standard protocol should be put in place and the statistical calibration of this researcher should be done prior to data collection. However, if two or more researchers are involved in the assessment of agar plates, our results suggest that the protocols using software to undertake plate reading is preferred.