Endocarditis caused by Candida dubliniensis

Impact of Cigarette Smoke Condensate on Adhesion-Related Traits and Hemolysin Production of Oral Candida dubliniensis Isolates

BACKGROUND

Cigarette smoke is associated with higher oral Candida carriage and possible predisposition and increased susceptibility to oral candidal infection. Candida dubliniensis is associated with oral candidosis. Candidal adherence to buccal epithelial cells (BEC) and denture acrylic surfaces (DAS), germ tube (GT) formation, cell surface hydrophobicity (CSH) and hemolysin production are pathogenic traits of Candida.

OBJECTIVES

The impact of exposure to cigarette smoke on the aforementioned pathogenic attributes of oral C. dubliniensis has not been studied. Hence, the impact of cigarette smoke condensate (CSC) on adhesion to BEC and DAS, GT formation, CSH and hemolysin production of 20 oral C. dubliniensis isolates after exposure to CSC for 24, 48 and 72 h was ascertained.

METHODS

After preparation of the CSC, using an in-house smoking device, the Candida isolates were exposed to the CSC for 24, 48 and 72 h, by a previously described in vitro method. Thereafter, the adhesion to BEC and DAS, GT formation, CSH and hemolysin production of C. dubliniensis isolates was investigated by hitherto described in vitro assays.

RESULTS

Exposure to CSC significantly increased the ability of C. dubliniensis oral isolates to adhere to BEC, DAS, GT formation, CSH and produce hemolysin following 24-h, 48-h and 72-h exposure periods to CSC (P < 0.001 for all attributes tested).

CONCLUSIONS

Exposure of oral C. dubliniensis isolates to CSC may significantly promote in vitro adhesion traits and hemolysin production of these isolates, thereby augmenting its pathogenicity in vitro in the presence of cigarette smoke.

In vitro Post-Antifungal Effect of Posaconazole and Its Impact on Adhesion-Related Traits and Hemolysin Production of Oral Candida dubliniensis Isolates

OBJECTIVE

Candidal adherence to denture acrylic surfaces (DAS) and oral buccal epithelial cells (BEC), formation of candidal germ tubes (GT), candidal cell surface hydrophobicity (CSH), and hemolysin production are important pathogenic traits of Candida. The antifungal drug-induced post-antifungal effect (PAFE) also impacts the virulence of Candida. Candida dubliniensis isolates are associated with the causation of oral candidiasis which could be managed with posaconazole. Thus far there is no evidence on posaconazole-induced PAFE and its impact on adhesion-related attributes and production of hemolysin by C. dubliniensis isolates. Hence, the PAFE, adhesion to DAS and BEC, formation of GT, CSH, and hemolysin production of 20 oral C. dubliniensis isolates after brief exposure to posaconazole was ascertained.

MATERIALS AND METHODS

The PAFE, adherence to DAS and BEC, formation of GT, candidal CSH, and hemolysin production were investigated by hitherto described in vitro assays.

RESULTS

The mean PAFE (h) induced by posaconazole on C. dubliniensis isolates was 1.66. Exposure to posaconazole suppressed the ability of C. dubliniensis to adhere to DAS, BEC, formation of candidal GT, candidal CSH and to produce hemolysin by a reduction of 44, 33, 34, 36, and 15% (p < 0.005 to p < 0.001), respectively.

CONCLUSION

Exposure of C. dubliniensis isolates to posaconazole for a brief period induced an antimycotic impact by subduing its growth in addition to suppressing pathogenic adherence-associated attributes, as well as production of hemolysin.

Impact of Brief Exposure to Drugs with Antifungal Properties on the Susceptibility of Oral Candida dubliniensis Isolates to Lysozyme and Lactoferrin

OBJECTIVE

Lysozyme and lactoferrin have anti-candidal activity. Candida dubliniensis is associated with oral candidiasis. Candida infections are managed with nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine. Candida species undergo a brief exposure to therapeutic agents in the mouth. There is no data on the influence of limited exposure to antimycotics on the sensitivity of C. dubliniensis to lactoferrin and lysozyme. Hence, this study observed the changes in the sensitivity of C. dubliniensis to anti-candidal action of lactoferrin and lysozyme after transitory exposure to sub-lethal concentrations of antifungals.

MATERIALS AND METHODS

After determination of the minimum inhibitory concentration (MIC), 20 C. dubliniensis isolates were exposed to twice the concentration of MIC of nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine for 1 h. Drugs were removed by dilution and thereafter the susceptibility of these isolates to lysozyme and lactoferrin was determined by colony-forming unit quantification assay.

RESULTS

Exposure of C. dubliniensis to nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine resulted in an increase in susceptibility to lysozyme by 9.45, 30.82, 30.04, 50.64, 55.60, and 50.18%, respectively (p < 0.05 to p < 0.001). Exposure of C. dubliniensis to nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine resulted in an increase in susceptibility to lactoferrin by 13.54, 16.43, 17.58, 19.60, 21.32, and 18.73, respectively (p < 0.05 to p < 0.001).

CONCLUSION

Brief exposure to nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine enhances the antifungal effect of lysozyme and lactoferrin on C. dubliniensis isolates in vitro.

Impact of short-term exposure of antifungal agents on hemolysin activity of oral Candida dubliniensis isolates from Kuwait and Sri Lanka

OBJECTIVE

Ability to produce hemolysin by Candida species is an important determinant of its pathogenicity. Candida dubliniensis is implicated in the causation of oral candidosis, which can be treated with polyene, echinocandin, and azole groups of antifungal agents as well as chlorhexidine. After oral application, however, the concentrations of these agents tend to decrease quickly to subtherapeutic levels due to the peculiarity of the oral environment. In this study, we have evaluated the effect of short-term exposure of sublethal concentrations of these drugs on hemolysin production by oral C. dubliniensis isolates obtained from two different geographical locale.

MATERIALS AND METHODS

Twenty C. dubliniensis oral isolates obtained from Kuwait and Sri Lanka were exposed to sublethal concentrations of nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine for 1 h. Thereafter, the drugs were removed by dilution and the hemolysin production determined by a previously described plate assay.

RESULTS

Hemolysin production of these isolates was significantly suppressed with a percentage reduction of 17.09, 16.45, 17.09, 11.39, 8.23 and 12.03 following exposure to nystatin, amphotericin B, caspofungin, ketoconazole, fluconazole, and chlorhexidine, respectively.

CONCLUSION

Brief exposure to sublethal concentrations of drugs with antifungal properties appears to reduce the pathogenic potential of C. dubliniensis isolates by suppressing hemolysin production.

Meningitis Caused by Candida Dubliniensis in a Patient with Cirrhosis: A Case Report and Review of the Literature

Candida species, including Candida dubliniensis, are a rare cause of meningitis. Herein, we report the second case of C. dubliniensis meningitis in a 49-year-old man with a history of hepatitis C virus-related cirrhosis, substance use disorder, and recent exposure to intravenous antibiotic therapy, presenting with confusion, abnormal gait, and urinary incontinence. Magnetic resonance imaging (MRI) of the brain showed marked hydrocephalus and leptomeningeal enhancement. Initial cerebrospinal fluid (CSF) studies were concerning for bacterial meningitis, although cultures were negative. Despite empiric treatment with broad-spectrum antibiotics, the patient's mental status declined. The diagnosis of C. dubliniensis meningitis was not made until the third lumbar puncture. The patient was treated with liposomal amphotericin B and flucytosine. Despite improvement of hydrocephalus on MRI of the brain and sterilization of CSF, the patient's mental status declined and he expired. This case highlights the difficulty in the diagnosis of C. dubliniensis meningitis as multiple lumbar punctures may be necessary. C. dubliniensis meningitis should be considered in the differential diagnosis for a patient with risk factors such as end-stage liver disease, human immunodeficiency virus infection, recent chemotherapy, substance use disorders, and recent broad-spectrum antibiotic use. A high index of suspicion is necessary as delay in initiation of therapy is associated with high mortality. The optimal treatment strategy has not been determined.

Caspofungin-induced in-vitro post-antifungal effect and its impact on adhesion related traits of oral Candida dubliniensis and Candida albicans isolates

Adhesion to buccal epithelial cells (BEC) and denture acrylic surfaces (DAS), germ tube (GT) formation and cell surface hydrophobicity (CSH) are all virulence traits involved in the pathogenicity of Candida. Post-antifungal effect (PAFE) also have a bearing on pathogenicity and virulence of Candida. Candida dubliniensis is associated with oral and systemic candidosis, which can be managed with caspofungin. There is no published information on caspofungin-induced PAFE and its impact on adhesion traits of C. dubliniensis isolates. Thus, the purpose of this investigation was to determine the in vitro duration of PAFE on 20 C. dubliniensis isolates following transient exposure to caspofungin. Furthermore the impacts of caspofungin-induced PAFE on adhesion to BEC and DAS, GT formation and CSH of these isolates were also determined. After establishing the minimum inhibitory concentration (MIC) of caspofungin, C. dubliniensis isolates were exposed to sub-lethal concentrations (×3 MIC) of caspofungin for 1 hr. Thereafter the duration of PAFE, adhesion to BEC and DAS, GT formation and CSH were determined by previously described in-vitro assays. MIC (μg/mL) of C. dubliniensis isolates to caspofungin ranged from 0.004 to 0.19. Caspofungin-induced mean PAFE on C. dubliniensis isolates was 2.17 hr. Exposure to caspofungin suppressed the ability of C. dubliniensis isolates to adhere to BEC and DAS, form GT and CSH by 69.97%, 71.95%, 90.06% and 32.29% (P < 0.001 for all), respectively. Thus, transient exposure of C. dubliniensis isolates to caspofungin produces an antifungal effect not only by suppressing its growth but also by altering its adhesion traits.

In vitro postantifungal effect, adhesion traits and haemolysin production of Candida dubliniensis isolates following exposure to 5-fluorocytosine

The phenomenon of postantifungal effect (PAFE), which is the suppression of candidal growth following brief exposure to antifungal agents, is linked with candidal pathogenicity. Adhesion to buccal epithelial cells (BEC), germ tube (GT) formation and relative cell surface hydrophobicity (CSH) are all adhesion traits of candidal pathogenicity. Ability to produce haemolysin by Candida species is also a determinant of its pathogenicity. There is no information on either the PAFE or its impact on adhesion traits and haemolysin production of oral Candida dubliniensis isolates following exposure to 5-fluorocytosine (5-FC). Hence, the focus of this investigation was to research the in vitro PAFE, adhesion to BEC, GT formation, relative CSH and haemolysin production on 20 C. dubliniensis isolates following exposure to 5-FC. Following obtaining the minimum inhibitory concentration (MIC) of 5-FC, isolates of C. dubliniensis were exposed to sub-lethal concentrations (×3 MIC) of 5-FC for 1 h. After this brief exposure, the antimycotic was removed and PAFE, adhesion to BEC, GT formation, relative CSH and haemolysin production was determined by formerly described in vitro methods. MIC (μg/ml) of C. dubliniensis isolates to 5-FC ranged from 0.002 to 0.125. The mean PAFE (hours) elicited by 5-FC on C. dubliniensis isolates was approximately 1 h. Exposure to 5-FC suppressed the ability of C. dubliniensis isolates to adhere BEC, GT formation, relative CSH and haemolysin activity by a mean percentage reduction in 50.98%, 29.51%, 36.79% and 12.75% (P < 0.001 for all) respectively. Therefore, brief exposure of C. dubliniensis isolates to 5-FC appears to exert an antifungal effect by subduing its growth, adhesion traits as well as haemolysin production.

In vitro adhesion of oral Candida dubliniensis isolates to acrylic denture surfaces following brief exposure to sub-cidal concentrations of polyenes, azoles and chlorhexidine

OBJECTIVES

We aimed to investigate the effect of brief exposure to sub-cidal concentrations of nystatin, amphotericin B, ketoconazole, fluconazole and chlorhexidine gluconate on the adhesion of oral Candida dubliniensis isolates to the surface of acrylic dentures.

METHODS

After determining the minimum inhibitory concentration of each drug, 20 oral isolates of C. dubliniensis were exposed to sub-cidal concentrations of the drugs for 1 h. The drugs were then removed by dilution, and the adhesion of the isolates to denture acrylic strips was assessed by an in vitro adhesion assay.

RESULTS

Compared to the controls, exposure to nystatin, amphotericin B, ketoconazole, fluconazole and chlorhexidine gluconate suppressed the ability of C. dubliniensis isolates to adhere to acrylic denture surfaces with a reduction of 74.68, 74.27, 57.31, 44.57 and 56.53% (p < 0.001 for all drugs), respectively.

CONCLUSIONS

Brief exposure to sub-cidal concentrations of anti-mycotics suppressed the adhesion of C. dubliniensis oral isolates to acrylic denture surfaces.

Impact of brief and sequential exposure to nystatin, amphotericin B, ketoconazole, and fluconazole in modulating adhesion traits of oral Candida dubliniensis isolates

AIM

Candida adherence is implicated in the pathogenesis of oral candidosis. Adhesion to buccal epithelial cells (BEC), germ tube (GT) formation, and relative cell surface hydrophobicity (CSH) are colonization attributes of candidal pathogenicity. Candida dubliniensis (C. dubliniensis) is allied with recurrent oral candidosis, which can be treated with nystatin, amphotericin B, ketoconazole, and fluconazole. Due to the diluent effect of saliva and the cleansing effect of the oral musculature in the oral cavity C. dubliniensis isolates undergo brief and sequential exposure to antifungal agents during therapy. Thus, in the present study, we evaluated the adhesion to BEC, GT formation, and the CSH of oral isolates of C. dubliniensis following brief and sequential exposure to nystatin, amphotericin B, ketoconazole, and fluconazole.

METHODS

After determining the minimum inhibitory concentration (MIC) of the aforementioned drugs, 20 oral isolates of C. dubliniensis were briefly (1 h), and sequentially (10 days) exposed to subcidal concentrations of these drugs. Following drug removal, adhesion to BEC, GT formation, and CSH of these isolates were determined.

RESULTS

The percentage reduction of adhesion to BEC, GT formation, and CSH of the isolates following exposure to antifungal agents were as follows: nystatin: 53.55%, 33.98%, and 29.83% (P < 0.001); amphotericin B: 53.84%, 36.23%, and 28.97% (P < 0.001); ketoconazole: 37.43%, 20.51%, and 16.49% (P < 0.001); and fluconazole: 8.93% (P < 0.001), 1.6%, and 0.63% (P > 0.05).

CONCLUSIONS

Brief and sequential exposure of C. dubliniensis to antifungal agents would continue to wield an antifungal effect by altering its adhesion attributes, and elucidate possible pharmacodynamics by which antifungal agents might operate in modulating candidal adherence.