Cryptococcus laurentii: a wild yeast for xylanase production from agricultural by-products.

The development of technologies that allow the production of enzymes at a competitive cost is of great importance for several biotechnological applications, and the use of agro-industrial by-products is an excellent alternative to minimize costs and reduce environmental impacts. This study aimed to produce endo-xylanases using agro-industrial substrates rich in hemicellulose as sources of xylan in culture media. For this purpose, the yeast Cryptococcus laurentti and five lignocellulosic materials (defatted rice bran, rice husk, corn cob, oat husks, and soybean tegument), with and without pretreatment, were used as a source of xylan for enzyme production. To insert the by-products in the culture medium, they were dried and treated (if applicable) with 4% (w.v-1) NaOH and then added in a concentration of 2% (w.v-1). The cultures were agitated for 96 h, and the aliquots were removed to determine the enzymatic activities. Among the by-products studied, the maximum activity (8.7 U. mL-1 at pH 7.3) was obtained where rice bran was used. In contrast, corn cob was the by-product that resulted in lower enzyme production (1.6 U.mL-1). Thus, the defatted rice bran deserves special attention in front of the other by-products used since it provides the necessary substrate for producing endo-xylanases by yeast.

Usual Presentation Of An Unusual Pathogen - Cryptococcus Laurentii Meningitis: A Case Report.

Infections caused by non-neoformans Cryptococcus spp., including Cryptococcus laurentii, previously thought to be saprophyte and non-pathogenic, have become more common during the past few years, particularly in immunocompromised hosts. To the best of our knowledge here, we present the first case of meningitis in an immunocompromised patient due to a fungus that has never been reported in Pakistan. Our patient, a 40-year old male, who had acquired immunodeficiency syndrome (AIDS) was diagnosed as Cryptococcus laurentti meningitis, with a rare neurological manifestation i.e., cryptococcomas and lepto-meningitis. We presume that exposure to pigeon droppings and acquired immunodeficiency syndrome were the risk factors for this case report. He was treated with liposomal Amphotericin (LAMB) and fluconazole but unfortunately, he rapidly deteriorated and ultimately succumbed to the infection. This case underscores the significance of prompt diagnosis and vigorous treatment of Cryptococcus laurentii meningitis, as well as the need for continued surveillance in immunocompromised individuals.

A comprehensive study on diesel oil bioremediation under microcosm conditions using a combined microbiological, enzymatic, mass spectrometry, and metabarcoding approach.

This study aims at the application of a marine fungal consortium (Aspergillus sclerotiorum CRM 348 and Cryptococcus laurentii CRM 707) for the bioremediation of diesel oil-contaminated soil under microcosm conditions. The impact of biostimulation (BS) and/or bioaugmentation (BA) treatments on diesel-oil biodegradation, soil quality, and the structure of the microbial community were studied. The use of the fungal consortium together with nutrients (BA/BS) resulted in a TPH (Total Petroleum Hydrocarbon) degradation 42% higher than that obtained by natural attenuation (NA) within 120 days. For the same period, a 72 to 92% removal of short-chain alkanes (C12 to C19) was obtained by BA/BS, while only 3 to 65% removal was achieved by NA. BA/BS also showed high degradation efficiency of long-chain alkanes (C20 to C24) at 120 days, reaching 90 and 92% of degradation of icosane and heneicosane, respectively. In contrast, an increase in the levels of cyclosiloxanes (characterized as bacterial bioemulsifiers and biosurfactants) was observed in the soil treated by the consortium. Conversely, the NA presented a maximum of 37% of degradation of these alkane fractions. The 5-ringed PAH benzo(a)pyrene, was removed significantly better with the BA/BS treatment than with the NA (48 vs. 38 % of biodegradation, respectively). Metabarcoding analysis revealed that BA/BS caused a decrease in the soil microbial diversity with a concomitant increase in the abundance of specific microbial groups, including hydrocarbon-degrading (bacteria and fungi) and also an enhancement in soil microbial activity. Our results highlight the great potential of this consortium for soil treatment after diesel spills, as well as the relevance of the massive sequencing, enzymatic, microbiological and GC-HRMS analyses for a better understanding of diesel bioremediation.

Anionic exopolysaccharide from Cryptococcus laurentii 70766 as an alternative for alginate for biomedical hydrogels.

Alginates are widely used polysaccharides for biomaterials engineering, which functional properties depend on guluronic and mannuronic acid as the building blocks. In this study, enzymatically crosslinked hydrogels based on sodium alginate (Na-Alg) and the exopolysaccharide (EPS) derived from Cryptococcus laurentii 70766 with glucuronic acid residues were synthesized and characterized as a new potential source of polysaccharide for biomaterials engineering. The EPS was extracted (1.05 ± 0.57 g/L) through ethanol precipitation. Then the EPS and Na-Alg were functionalized with tyramine hydrochloride to produce enzymatically crosslinked hydrogels in the presence of horseradish peroxidase (HRP) and H2O2. Major characteristics of the hydrogels such as gelling time, swelling ratio, rheology, cell viability, and biodegradability were studied. The swelling ratio and degradation profile of both hydrogels showed negative values, indicating an increased crosslinking degree and a lower water uptake percentage. The EPS hydrogel showed similar gelation kinetics compared to the Alg hydrogel. The EPS and its hydrogel were found cytocompatible. The results indicate the potential of EPS from C. laurentii 70766 for biomedical engineering due to its biocompatibility and degradability. Further studies are needed to confirm this EPS as an alternative for Alg in tissue engineering applications, particularly in the development of wound dressing products.

Metabolomics reveals key resistant responses in tomato fruit induced by Cryptococcus laurentii.

To investigate the mechanisms underlying inducible resistance in postharvest tomato fruit, non-targeted metabolome analysis was performed to uncover metabolic changes in tomato fruit upon Cryptococcus laurentii treatment. 289 and 149 metabolites were identified in positive and negative ion modes, respectively. A total of 59 metabolites, mainly including phenylpropanoids, flavonoids and phenolic acids, were differently abundant in C. laurentii-treated tomato fruit. Moreover, key metabolites involved in phenylpropanoid biosynthesis pathway, especially chlorogenic acid, caffeic acid and ferulic acid were identified through KEGG enrichment analysis. Enhanced levels of phenolic acids indicated activation of the phenylpropanoid biosynthesis pathway, which is a classic metabolic pathway associated with inducible resistance, suggesting that its activation and consequent metabolic changes contributed to inducible resistence induced by C. laurentii. Our findings would provide new understanding of resistance induction mechanism in tomato fruit from the metabolic perspective, and offer novel insights for new approaches reducing postharvest loss on tomato.

Comparison of clinical and biological characteristics of HIV-infected patients presenting Cryptococcus neoformans versus C. curvatus/C. laurentii meningitis.

BACKGROUND: Cryptococcal meningitis is mainly caused by Cryptococcus neoformans/C. gattii complex. We compared the clinical, biological, and antifungal susceptibility profiles of isolates from HIV-Infected Patients (HIVIP) with C. neoformans (Cn) versus C. curvatus/C. laurentii (Cc/Cl) meningitis. METHODS: Comparative analytical study were conducted. Apart from patients' clinical data, the following analysis were performed and the results were compared in both groups: biochemical examination, cryptococcal antigen test, India ink staining, and culture on Cerebral Spinal Fluid (CSF), strains identification by mass spectrometry, ITS sequencing, PCR serotyping and antifungal susceptibility. The main outcome variable was the "species of Cryptococcus identified", which was compared to other variables of the same type using the Pearson Chi-square test or the Fisher exact test. RESULTS: A total of 23 (79.3%) Cn meningitis cases versus 6 (20.7%) Cc/Cl meningitis were retained. Cn meningitis was more frequently associated with headache (100% vs 50%, p = 0.005) than Cc/Cl meningitis and meningeal signs were more frequent in Cn infected patients. Biologically, hypoglycorrhachia and low CD4 count were more observed in Cn group (90% vs 20% of patients, p = 0.01; 45.6 vs 129.8 cells/µL, p = 0.02, respectively). A higher proportion of Cn strains (91.3%) showed a low Minimum Inhibitory Concentration (MIC) (< 8 mg/L) for fluconazole compared to Cc/Cl strains (66.7%). Also, Cc/Cl strains resistant to 5-flucytosine and amphotericin B were found in 16.7% of cases for each of the two antifungal agents. Cryptococcus detection by routine analysis (India ink, culture, and antigens) was better for Cn samples than Cc/Cl. Except ITS sequencing, which identified all strains of both groups, mass spectrometry and serotyping PCR identified Cn strains better than Cc/Cl (100% vs 80%, p = 0.1; 100% vs 0%, p < 0.0001, respectively). After treatment with amphotericin B, 5-flucytosine, and fluconazole in both groups, the outcome was similar. CONCLUSIONS: Clinical presentation of Cn meningitis is certainly more severe than that of Cc/Cl meningitis, but Cc/Cl infection should be considered in the management of HIVIP with meningeal syndrome because of the diagnostic difficulty and the high MICs of antifungal agents required for the treatment of meningitis due to these cryptococcal species.

Kosakonia radicincitans and Cryptococcus laurentii controlled Penicillium expansum rot and decreased patulin production at 4 and 25 °C.

In the present work, we evaluated the effects of a mixture of biocontrol agents against two toxigenic strains of Penicillium expansum isolated in Argentine Patagonia from pome fruits. The two strains, INTA-5 and INTA-10, were previusly selected among ten strains coming from the Alto Valle (Rio Negro-Argentina) for their high production of patulin. For the biocontrol, Kosakonia radicincitans, Cryptococcus laurentii, and Rhodosporidium fluviale were tested in vitro experiments on Potato Dextrose Agar (PDA) dishes against the INTA-5 and INTA-10 strains. The bacterium K. radicincitans and the yeast C. laurentii were selected to be used in a mixture due to their capacity to control the fungus and reduce the mycotoxin severely. In vitro assays with the mixture showed a high antagonism against P. expansum INTA-5 and INTA-10, at 21 d of incubation at 25 °C and a patulin reduction of 98%. The mixture of microorganisms was also effective in apples stored at 25 °C for 10 d and 4 °C for 30 d. At cold storage, the mixture controlled moderately the development of rot and decreased patulin concentration. At 25 °C, the pathogen's optimal growth temperature, the mixture of Biological Control Agent (BCAs) assured both the control of rot and decrease of patulin concentration. The combination of two microorganisms, with different requirements and abilities, resulted in a mix with a strong antagonism against P. expansum with the capability to decrease the patulin concentration. Treatment with the selected mixture could be a good option for controlling strains with different behaviours and in different environmental conditions.

Synergistic effect of carboxymethylcellulose and Cryptococcus laurentii on suppressing green mould of postharvest grapefruit and its mechanism.

The synergistic effects of carboxymethylcellulose (CMC) combined with Cryptococcus laurentii FRUC DJ1 were studied on controlling green mould resulting from Penicillium digitatum in grapefruit fruit. The results indicate that both C. laurentii and the CMC treatment suppressed P. digitatum conidia germination. In addition, C. laurentii growth in vitro was not affected by low CMC concentrations, nevertheless, the biofilm of C. laurentii was enhanced. Compared with the control fruit, the grapefruit had a lower green mould in all treatments. Significantly synergistic effects were caused by combining C. laurentii and CMC on minimum decay incidence and lesion diameter. Combined treatment induced defence enzyme activities, including chitinase, ß-1,3-glucanase, peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase, together with disease tolerance-associated total phenol. Also, this combination inhibited the pathogen growth by adhered to the hyphae and reduced its infection in fruit wounds. Moreover, the commercial quality parameters in the combined treatment of C. laurentii and CMC, including weight loss, total soluble solids, ascorbic acid, and titratable acidity, were superior to single treatment. The combination of C. laurentii and CMC can not only control postharvest decay but also maintain fruit qualities. Thus, it can be used in grapefruit for commercial purposes.

A rare case of cutaneous Papiliotrema (Cryptococcus) laurentii infection in a 23-year-old Caucasian woman affected by an autoimmune thyroid disorder with hypothyroidism.

In recent years, the frequency of infections due to saprophytic fungi has increased. Cryptococcus laurentii, recently classified as Papiliotrema laurentii, is responsible for fungemia, meningitis, and superficial infections. Here, we report the first case of cutaneous Papiliotrema (Cryptococcus) laurentii infection in a 23-year-old Caucasian woman affected by an autoimmune thyroiditis with hypothyroidism. Impairments of the immune system are often associated with unusual fungal infections, which cannot be neglected. The isolate strain was susceptible to Amphotericin B while resistant to fluconazole, itraconazole, voriconazole, and terbinafine. The patient was successfully treated with Amphotericin B.

First case report of Cryptococcus laurentii knee infection in a previously healthy patient.

BACKGROUND: The purpose of this case report was to report a case of Cryptococcus laurentii infection in the left knee of a previously healthy 29 year old male patient. CASE PRESENTATION: After an initial misdiagnosis and 7 months of failed treatment, the patient received nearly a month of treatment with voriconazole (200 mg IV q12 h) and knee irrigation with amphotericin B until the infection was controlled. The treatment continued with fluconazole for nearly 7 months and approximately 5 weeks of antibiotic treatment for a skin bacterial coinfection. In the end, the patient's symptoms disappeared completely, the left knee recovered well, and there was no recurrence of infection. CONCLUSION: The key points of successful treatment in this case were the thorough debridement, the adequate course of knee irrigation with antifungal drugs and more than 6 months of oral antifungal drugs that were able to eradicate the infection.

Orange peel waste-based liquid medium for biodiesel production by oleaginous yeasts.

Orange peel waste (OPW), the primary byproduct of the juice extraction process, is annually generated in massive amounts (21 Mton), and its aqueous extraction in biorefining operations yields a liquid fraction, referred to as orange peel extract (OPE). Although OPE contains significant amounts of easily assimilable carbohydrates, such as fructose, glucose, and sucrose, no investigations have been conducted yet to assess its possible use in biodiesel production by oleaginous yeasts. Consequently, the objective of the present study was to assess whether OPE might act as the basis of a liquid medium for microbial lipid production. A screening conducted with 18 strains of oleaginous yeasts in shaken flask on the OPE-based medium showed that Rhodosporidium toruloides NRRL 1091 and Cryptococcus laurentii UCD 68-201 gave the best results in terms of lipid production (5.8 and 4.5 g L-1, respectively) and accumulation (77 and 47% on a dry matter basis, respectively). The subsequent scale transfer of the process to a 3-L STR operated in batch mode halved the time required to reach the lipid peak with the ensuing increase in volumetric productivities in R. toruloides NRRL 1091 (3646 mg L-1 day-1) and C. laurentii UCD 68-201 (2970.7 mg L-1 day-1). The biodiesel yields from the lipids of the former and the latter strain were 36.9 and 31.9%, respectively. Based on multivariate analysis of fatty acid methyl ester compositions, the lipids from the former and the latter strain were highly resembling those of Jatropha and palm oils, two commonly used feedstocks for biodiesel manufacturing.

A Study of the Disruptive Effect of the Acetate Fraction of Punica granatum Extract on Cryptococcus Biofilms.

Cryptococcosis, caused by yeasts of the genus Cryptococcus, is an infectious disease with a worldwide distribution. Cryptococcus neoformans and Cryptococcus gattii are the species that commonly cause this disease in humans; however, infections caused by Cryptococcus laurentii, especially in immunocompromised patients, are increasingly being reported. Owing to the increase in the resistance of fungi to antifungals, and a lack of treatment options, it is important to seek new therapeutic alternatives such as natural products. Among these are plant species such as Punica granatum, which is used in folk medicine to treat various diseases. This study aimed to evaluate the activity of the acetate fraction of P. granatum leaf extract against environmental and clinical isolates of Cryptococcus. Three environmental isolates of C. laurentii, PMN, PMA, and PJL II, isolated from soils of different municipalities in the state of Maranhão, a clinical isolate, C. gattii, from a patient with neurocryptococcosis, and a standard strain of C. gattii (ATCC 32068) were used. The minimum and fractional inhibitory concentrations (MIC and FIC, respectively) and time-kill curve of the extract and fluconazole were determined to assess the susceptibility profile of the fungal isolates. Larvae of Tenebrio molitor were infected with Cryptococcus strains, and the effects of acetate fraction of P. granatum extract and fluconazole on the survival and fungal burden were determined. The extract activity was tested against pre-formed biofilms. The acetate fraction of P. granatum extract showed promising antifungal activity against all the species of Cryptococcus evaluated in this study, with an MIC value lower than that of fluconazole. The indices obtained in the FIC test indicated that the antimicrobial effect of the combination of the extract and antifungal was indifferent for 80% of the isolates. The P. granatum acetate fraction reduced the pre-formed biofilm of some isolates, showing better activity than fluconazole, which is consistent with results from fluorescence microscopy. This is the first study on the use of P. granatum and its ability to inhibit Cryptococcus biofilms; therefore, further studies and tests are needed to investigate the components and mechanism of action of P. granatum against cryptococcosis agents.

Clinical diversity of invasive cryptococcosis in AIDS patients from central China: report of two cases with review of literature.

BACKGROUND: Although antiretroviral therapy (ART) has greatly improved the prognosis of acquired immunodeficiency syndrome (AIDS) patients globally, opportunistic infections (OIs) are still common in Chinese AIDS patients, especially cryptococcosis. CASE PRESENTATION: We described here two Chinese AIDS patients with cryptococcal infections. Case one was a fifty-year-old male. At admission, he was conscious and oriented, with papulonodular and umbilicated skin lesions, some with ulceration and central necrosis resembling molluscum contagiosum. The overall impression reminded us of talaromycosis: we therefore initiated empirical treatment with amphotericin B, even though the case history of this patient did not support such a diagnosis. On the second day of infusion, the patient complained of intermittent headache, but the brain CT revealed no abnormalities. On the third day, a lumbar puncture was performed. The cerebral spinal fluid (CSF) was turbid, with slightly increased pressure. India ink staining was positive, but the cryptococcus antigen latex agglutination test (CrAgLAT: IMMY, USA) was negative. Two days later, the blood culture showed a growth of Cryptococcus neoformans, and the same result came from the skin culture. We added fluconazole to the patient's treatment, but unfortunately, he died three days later. Case two was a sixty-four-year-old female patient with mild fever, productive cough, dyspnea upon movement, and swelling in both lower limbs. The patient was empirically put on cotrimoxazole per os and moxifloxacin by infusion. A bronchofibroscopy was conducted with a fungal culture, showing growth of Cryptococcus laurentii colonies. Amphotericin B was started thereafter but discontinued three days later in favor of fluconazole 400 mg/d due to worsening renal function. The patient became afebrile after 72 h of treatment with considerable improvement of other comorbidities and was finally discharged with continuing oral antifungal therapy. CONCLUSIONS: Our cases illustrate that cryptococcal disease is an important consideration when treating immunocompromised individuals such as AIDS patients. Life threatening meningitis or meningoencephalitis caused by C. neoformansmay still common in these populations and can vary greatly in clinical presentations, especially with regard to skin lesions. Pulmonary cryptococcosis caused by C. laurentii is rare, but should also be considered in certain contexts. Guidelines for its earlier diagnosis, treatment and prophylaxis are needed.

Cryptococcus laurentii controls gray mold of cherry tomato fruit via modulation of ethylene-associated immune responses.

This research aimed to investigate the roles of phytohormone ethylene in cherry tomato fruit immune response against gray mold caused by Botrytis cinerea. Pretreatment with antagonistic yeast Cryptococcus laurentii resulted in a significantly decreased disease incidence of B. cinerea infection, and accompanied by a burst of ethylene production in the whole fruit. Blocking the ethylene perception by adding 1-MCP (5 µL L-1 or greater) remarkably weaken the protection ability of fruit itself and suppressed the C. laurentii-stimulated host immune response. 5 µL L-1 1-MCP prefumigation decreased the expression of ethylene biosynthesis and perception related genes SlACO1, SlACS2, SlERF1, SlPti5 and SlMPK3, and ethylene production in C. laurentii treated fruit. Consequently, the expressions of SlCHI9, SlGlub, SlPAL3, SlPR1 and SlPR5 up-regulated by the yeast were all impaired to different degrees by the 1-MCP prefumigation. These findings demonstrate that ethylene contributes to fruit immunity and C. laurentii-mediated immune responses of cherry tomato.

Cryptococcus laurentii fungemia in a low birth weight preterm neonate: India.

In the last few years, Cryptococcus laurentii infections have increased, particularly in immunocompromised patients. Here we report the first case of C. laurentii fungemia in low birth weight preterm infant from India. A preterm neonate was admitted for feeding intolerance and respiratory distress. Blood culture ascertained the causative organism as C. laurentii. The isolated strain was found susceptible to amphotericin B and the patient recovered following the administration of amphotericin B (5mg/kg body weight) for 8days.

Characterization and overexpression of RHO1 from Cryptococcus laurentii ZJU10 activates CWI signaling pathway on enhancing the inhibition of blue mold on pears.

Results from this study explored the inhibitory effect of RHO1 gene (GenBank accession number KY859864) from the antagonistic yeast, Cryptococcus laurentii ZJU10, on the control of Penicillium expansum in pear fruit and its possible mechanism involved. The RHO1 gene was successfully cloned and overexpressed in Saccharomyces cerevisiae. Sequence analysis showed high similarity with Rho family proteins, implying a primary role of Rho1 in the cell wall integrity (CWI) signaling pathway. Gene expression of RHO1 and other five CWI-related genes (including Pkc1, Rlm1, Fks1, Fks2 and Chs3) were significant up-regulated in the treatment of SC/Rho1-induced strain (Saccharomyces cerevisiae transformed with RHO1 and induced by galactose). Meanwhile, SC/Rho1-induced treatment reduced about 61.5% of disease incidence and almost 5-times lower lesion diameter compared to the control. In addition, the growth of transformed strains was slightly lower in contrast to the wild Saccharomyces cerevisiae and the induction of fruit resistance was significantly enhanced, which was tightly linked with triggering stronger host defensive responses by priming activation. This is the first study that Rho1 has a potential function of suppressing fungal disease in harvested fruit by activating CWI signaling pathway and indicates an alternative strategy for postharvest disease management.

Effect of Cryptococcus laurentii on inducing disease resistance in cherry tomato fruit with focus on the expression of defense-related genes.

The objective of this study was to prove and explain the disease resistance-inducing ability of Cryptococcus laurentii on cherry tomato, as well as assay its effect on fruit quality. Apart from disease incidence, activities of defense-related enzymes and expression of critical genes were studied. With pre-treatment of C. laurentii, disease incidences of Botrytis cinerea and Alternaria alternate infected fruits were both significantly reduced. Corresponding mechanism could be explained as C. laurentii can induce resistance in cherry tomato by activating the expression of important defense-related genes, such as genes involved in salicylic acid (SA) and jasmonic acid (JA) signaling pathways and genes encoding pathogenesis related proteins, thus activating comprehensive defense reaction against pathogen invasion. Coupled with the results that fruit color was improved and other physicochemical parameters remained uninfluenced, our study suggests that pre-treatment with C. laurentii can be a promising method to preserve cherry tomato fruits.

Cutaneotrichosporon (Trichosporon) debeurmannianum: A Rare Yeast Isolated from Blood and Urine Samples.

Cutaneotrichosporon (Trichosporon) debeurmannianum is a rarely isolated yeast from clinical samples. Nine isolates of this yeast were identified from clinical samples within a period of 3 years from June 2012 to May 2015. These isolates were from blood and urine samples sent to a clinical mycology laboratory of a tertiary care hospital in Assam, North East India. Clinically, the patients were diagnosed as septicemia and urinary tract infection. The age of the patients ranged from 2 to 50 years. Identification was made by sequencing the ITS region of ribosomal RNA gene. Antifungal susceptibility test by disk diffusion method (CLSI, M44-A) showed all the isolates to be sensitive to fluconazole and voriconazole. Vitek 2 compact commercial yeast identification system misidentified this yeast as Cryptococcus laurentii and low discrimination Cryptococcus laurentii/Trichosporon mucoides. This species was originally named as Trichosporon debeurmannianum. In 2015, this yeast has been included into new genera Cutaneotrichosporon based on an integrated phylogenetic classification of the Tremellomycetes. To the best of our knowledge, this is the first report of identification of this species from blood and urine samples of clinically suspected cases. We are reporting these isolates because of their rarity in clinical samples. The pathogenic potential and epidemiological relevance of this yeast remains to be seen.

Antifungal and Anti-Biofilm Activity of Essential Oil Active Components against Cryptococcus neoformans and Cryptococcus laurentii.

Cryptococcosis is an emerging and recalcitrant systemic infection occurring in immunocompromised patients. This invasive fungal infection is difficult to treat due to the ability of Cryptococcus neoformans and Cryptococcus laurentii to form biofilms resistant to standard antifungal treatment. The toxicity concern of these drugs has stimulated the search for natural therapeutic alternatives. Essential oil and their active components (EO-ACs) have shown to possess the variety of biological and pharmacological properties. In the present investigation the effect of six (EO-ACs) sourced from Oregano oil (Carvacrol), Cinnamon oil (Cinnamaldehyde), Lemongrass oil (Citral), Clove oil (Eugenol), Peppermint oil (Menthol) and Thyme oil (thymol) against three infectious forms; planktonic cells, biofilm formation and preformed biofilm of C. neoformans and C. laurentii were evaluated as compared to standard drugs. Data showed that antibiofilm activity of the tested EO-ACs were in the order: thymol>carvacrol>citral>eugenol=cinnamaldehyde>menthol respectively. The three most potent EO-ACs, thymol, carvacrol, and citral showed excellent antibiofilm activity at a much lower concentration against C. laurentii in comparison to C. neoformans indicating the resistant nature of the latter. Effect of the potent EO-ACs on the biofilm morphology was visualized using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), which revealed the absence of extracellular polymeric matrix (EPM), reduction in cellular density and alteration in the surface morphology of biofilm cells. Further, to realize the efficacy of the EO-ACs in terms of human safety, cytotoxicity assays and co-culture model were evaluated. Thymol and carvacrol as compared to citral were the most efficient in terms of human safety in keratinocyte- Cryptococcus sp. co-culture infection model suggesting that these two can be further exploited as cost-effective and non-toxic anti-cryptococcal drugs.

Perspectives on non-neoformans cryptococcal opportunistic infections.

Non-neoformans Cryptococcus species, including C. laurentii and C. albidus, have historically been classified as exclusively saprophytic. However, recent studies have increasingly implicated these organisms as the causative agent of opportunistic infections in humans. Herein, the case is presented of C. laurentii meningitis in a critically ill patient receiving corticosteroids. C. laurentii has been implicated in an additional 18 cases of opportunistic infection, predominantly of the skin, bloodstream, and central nervous system. The most clinically significant risk factors for non-neoformans cryptococcal infections include: impaired cell-mediated immunity, recent corticosteroid use, and invasive catheter placement. This article provides a comprehensive review of the clinical relevance, pathogenesis, risk factors, and treatment of non-neoformans Cryptococcus species.