Disseminated Cryptococcosis and Fluconazole Resistant Oral Candidiasis in a Patient with Acquired Immunodeficiency Syndrome (aids)

Disseminated cryptococcosis and recurrent oral candidiasis was presented in a-heterosexual AIDS patient. Candida tropicalis (C.tropicalis) was isolated from the oral pseudomembranous plaques and Cryptococcus neoformans (C. neoformans) was isolated from maculopapular lesions on body parts (face, hands and chest) and body fluids (urine, expectorated sputum, and cerebrospinal fluid). In vitro drug susceptibility testing on the yeast isolates demonstrated resistance to fluconazole acquired by C. tropicalis which was a suggestive possible root cause of recurrent oral candidiasis in this patient. Copyright © 2010 Kothavade et al. This is an open-access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Case Report A 34-year-old heterosexual HIV-I positive male developed mucopurulent productive cough, recurrent oral plaques, occasional syncope, and neurological symptoms that included headache and dizziness. Physical examination revealed discrete erythematous maculopapular lesions on his face (Figure 1), neck, chest, and both hands. There were not any significant enlargement of the cervical lymph nodes, and oral examination revealed pseudo-membranous plaques (Figure 1). He was previously treated with anti-fungal drugs (fluconazole and amphotericin-B), primary anti-tuberculous drugs (isoniazid, rifampin, ethambutol, and streptomycin), and an antigiardial drug (tinidazole) for giardiasis, caused by, Giardia lamblia. The CD4+ lymphocyte count for this patient was 40 cells/μl with a CD4+/CD8+ ratio of 1:72. Despite a history of multiple unprotected sexual exposures, the patient tested negative for venereal disease. The skin biopsies and body fluids, such as, cerebrospinal fluid (CSF), urine, and mucopurulent expectorated sputum, showed encapsulated yeasts in India-ink-wet-mount preparation. The cultures for acid-fast bacilli (AFB) on Lowenstein-Jenson and non-selective Middle-brook 7H12 agar media were negative. Periodic-acid-Schiff and Grocott-Gomori-methylamine-silver-stained smears were negative for Pneumocystis carinii. Serum and CSF tested positive for capsular Cryptococcal polysaccharide antigen using the latex agglutination test with a titer of 1:1015. Skin sections revealed gelatinous troma (Figure 2) filled with numerous encapsulated yeast cells (Figure 3). Biopsied specimens of skin and other body fluids (CSF, urine, and sputum) yielded the growth of C. neoformans on Sabouraud's dextrose agar (SDA) medium. The resultant mucoid-cream-colored colonies were negative for germ tube and positive for urease test. Colonies failed to grow on Cyclohexamide-supplemented SDA. Colonic growth at 37 o C on plain SDA was weakly positive. Microscopic examination of the Gram-stain preparation from a portion of scraped oral lesions showed Gram-positive yeasts and pseudo-hyphal forms. The remaining portion the scraped oral lesions …

The skin biopsies and body fluids, such as, cerebrospinal fluid (CSF), urine, and mucopurulent expectorated sputum, showed encapsulated yeasts in India-ink-wet-mount preparation. The cultures for acid-fast bacilli (AFB) on Lowerrstein-Jenson and nbn-selective Middle-brook 7H12 agar media were negative. Periodic-acid-schiff and Grocott-Gomorimethylarnine-silver-stained smears were negative for Pneumoc)tstis carinii. Serum and CSF tested positive for capsular Cryptococcal polysaccharide antigen using the latex agglutination test with a titer of 1 : 1 0 1 5. Skin sections revealed gelatinous troma ( Figure 2) filled with numerous encapsulated yeast cells ( Figure 3). Biopsied specimens of skin and other body fluids (CSF, urine, and sputum) yielded the growth of C. neoformans on Sabouraud,s dextrose agar (SDA) medium, The resultant mucoid-creamcolored colonies were negative for germ tube and positive for urease test. Colonies failed to grow on Cyclohexarnide-supplemented SDA. Colonic growth at 37oC on plain SDA was weakly positive. Microscopic exarnination of the Gram-stain preparation fi'om a portion of scraped oral lesions showed Gram-positive yeasts and pseudo-hyphal forms. The remaining portion the scraped oral lesions were inoculated on SDA which then showed a typical growth of C. tropicals. Identification of C. tropicalis was further confirmed by the germ tube test; morphological characteristics were determined on cornmeal tween-S0-agar and Vitek-32 and Apl 20C AUX identification systeurs (bioMdrieux, Craponne, France). Drug susceptibility testing to fluconazole, ketoconazole, clotrirnazole, posaconazole, and arnphotericin-B was perfonned using the CLSI rricro-dilution method t1]. The in-ttitro drug susceptibility study revealed fluconazole resistance to C. tropicalis only; whereas C. neoformans were found to be susceptible to all antifungal agents. Lab investigations for further clinical managernent could not be followed as the patient died on the third day of his hospitalization.

Discussion
The two species of genus Cryptococcus (C. neofonnans and C. gatti   instead, there were extensive disseminated gelatinous-appearing lesions and large number of encapsulated yeasts. Comparable findings are seen in other full-blown AIDS patients as well 16,7,91. In this case study, the CD4+ cell count was an ideal marker to assess the immunological status of the patient because from the T lymphocyte population CD4+ and CD8+ cells are the key . elements in mounting immune responseagainit pathogenic organisms [9]. However, it has been observed from the in-vitro studies on human T cells that CD4+ plays a significant role in mediating CDg+ proliferation against C. neoformam [10]. The HIV infected patients are rrore prone to Cryptococcal infection when their CD4+ counts drop below 50-100 cell/rnm l1l,l2l. In vitro studies on human T cells, particularly CD4+ and CD8+ cells against C. neoformans, have demonstrated interleukin and transferrin receptor expression with subsequent proliferative response [10]. The production of IFN_ gamma from CD8+ cells have been found in inactivating encapsulated yeasts of C. neoformans within macrophages [13]. Hence CDg+ cells in immune response may be functioning independent of 67s . Kothavade er al -Disseminated cryptococcosis and candidiasis in AIDS CD4+ cells. Some experimental studies suggest, that appropriate CD4+ 5ignaling could allow CD8+ cells to respond against C. neoforaruans. Further studies are required in human T cells to explore the potential role of interleukin-2 and IFN-garnma in resolving the arnbiguity of CD4+-CD8+ Iinked response against C. neoformans infection. Inadequate T cell (CD4+/CD8+) response against C. neoformans infection leads to the death ofpatients suffering fi.om AIDS [14,10]. C. neoformans is the most common fatal mycosis in AIDS patients, but is less common in non-cell-mediated irnmunodeficiency [15,16], which suggest that CMI is an imporlant irnrnune mechanism in the clearance of C. neoformans. In the present case report, it appears that the low CD4+ lymphoc)'te count supports the opportunistic -_condition to establish. mixed fungal infections caused by C. neoformans and C. tropicalis. Unlike C. albicans, which can be occasionally found as a cornrnensal, C. tropicalis has almost always been associated with the development of fungal infections in imrnunocompromised patients [17]. Sorne reports frorn India suggests that C. tropicalis is the most prevalent yeast species responsible for causing infection in HIV/AIDS patients [18]. However, in the present case study, fluconazole-resistant C. tropicalis was isolated from the oral-pseudolnembranous lesions, which was an uncommon finding in the Indian subcontinent. Such observations might have been overlooked due to a lack of drug susceptibility studies or tracking of recurrent Candida infections in irnmunocompromised or imrnunocompetent patients in India. The extensive use of fluconazole in the clinical management of AIDS and in other high-risk patients could be the basic cause of increasing prevalence of Candida species other than C. albicans. Among these species C. *opicalis is predominant in some parts of the world U9,20,21,221. As a result, C. tropicalis has been emerging in both immunocompromised and immuno-competent patients; hence, it has been suggested that the use of fluconazole in a high-risk group ofpatients should be avoided [19]. Irrespective of host immune response and other predisposing factors, a pathogenicity of C. tropicalis, might be another contributing factor for its mucosal coloirization in the buccal cavity. Similarly, colonization in the gastrointestinal tract can lead to the penetration of sub-mucosal layers. Some clinical studies have shown that C. tropicalis is more virulent than C. albicans in neutropenic and non-neutropenic patients 123,241. The purified tropiase from C. tropicalis (a novel acid proteinase) demonstrated hemorrhagic activity and its ability to increase capillary permeability [25]. In-spite of the recurrent infections due to C. tropicalis in AIDS patients, there was no evidence of its dissemination. However, dissemination did occur due to encapsulated yeasts of C. neoformans. The dominant mechanism of C. negformans over C. tropicalis in immunocomprornised patients is still not clearly understood.
Antifungal drug intolerance is certainly a major challenge in the clinical management of AIDS and other neutropenic and non-neutropenic patients (with several underlying subclinical conditions) 124,261.
An interesting clinico-mycological scenario in this report is that C. neoformans isolates were susceptible to fluconazole; however, C. tropicalis was found to be reSistant. Such clinico-mycological aspects must be carefully considered before switching to any antifungal therapeutic options. In addition, C. tropicalis has often been repofted as resistant to fluconazole 1271. The plausible mechanisms of fluconazole resistance have been extensively studied in the strains of C. albicans isolated from patients with HIV-AIDS-related oropharyngeal candidiasis [4]. Based on the literature survey, we believe that this could be the first case report from India presented with disseminated cryptococcosis and recurrent oral candidiasis due to fluconazole-resistant C. tropicalis. Development of fluconazole resistance in C. tropicalis could be due to several mechanisms.
Nevertheless, solne plausible mechanisms [28] could include, escalation of emanation (efflux) of the azole cornpounds due to (i) over-expression of efflux pumps, such as the adenine tri-phosphate binding cassette (ABC) transporter and major facilitator superfamily (MFS) membrane transporters; (ii) upregulation of the ERGI1 gene, coding for the azole target lanosterol 14 (cr)-demethylase; (iii) ERGll sequence related point rnutation and (iv) decreased affinity of azoles for their target-induced azole resistance. The acquired azole resistance could be the result of either one of these mechanisms or coupled with other steps in a harmonized manner 129). In general, azole resistance in C. tropicalis suggests that over-expression of CtERgi 1, associated with missense mutation in this gene, and seemed to be responsible for acquired azole resistance.
The intracranial pressure due to the heavy load of encapsulated yeasts and extensive colonization of fluconazole-resistant C. tropicalis (or intolerance to antifungal agents) could be the rnajor cause of the death of this patient. Epiderniological studies suggest that, increasing prevalence of C. tropicalis related to candidiasis in immunocompromised patients is due to the underlying subclinical conditions and subsequent antifungal agents associated toxicity; in addition to ... the genetic relatedness of the Candida species L30,31,32]. A1though, morbidity and mortality rates due to infections caused by C. nopicalrs have been reported more often, than those attributed to C. albicans [33]; it would be worth comparing this scenario in the cases of AIDS with disseminated cryptococcosis.
Comparing the susceptibility patterns of oral isolates during the highly active anti-retroviral therapy (HAART) era with those from 1994, suggest that: most cases of HlV-associated oropharyngeal candidiasis observed during the HAART era were caused by azole-susceptible strains. However, the reversion of isolates from azole-resistant to azolesusceptible was related to strain substitution [34].
Ever since the introduction of HAART, incidences of opportunistic infections such BS, cerebral toxoplasmosis, Pneumocystis carinii pneumonia and others have been declining. However, the prevalence of Candidial esophegitis remained unchanged [34]. These findings suggests that HAART does not play a significant role in minimizing any fluconazole drug resistance in Candida species and still remains a challenging problem for its long-term therapeutic application in HlV-infected or immunocompromised patients. J lnfect Dev Ctries 20101 4(10):674-678.

Gonclusion
The major gap in the pathogenicity of C. neoformans is the limited understanding of its dominant mechanism over C. tropicalis in AIDS patients. Secondly, the interlinked cellular mechanisms between CD4+ and CD8+ cells against C. neoformans infection remain unclear. Hence, some additional studies need to be performed on the expression of lL-z receptors and IFN-gamma production by human T cells (T cellsderived from the various clinical stages of HIV infection; may be from sero-rectaive to full blown AIDS stage).
Although, fluconazole is still the first line of treatment in a number of cases of invasive