The Relationship Between Candida And Melanin:a Preliminary Study

The word fungus is a word comes from Latin sfungus for mushrooms. There are about more than a million kinds in the world, but most fungus are good for human, only a are harmful to humans. The diseases caused by fungus are known as fungal diseases. The fungus not only can invade the skin and mucous membrane, but also can violation of muscles, bones and internal organs. Fungal infections are sorted into superficial fungal diseases and deep fungal diseases in clinic. Superficial fungal infections only invade shallow organizations such as human body skin, while deep fungal infection refers to the infringement of deep tissue organs of fungal infection. The reason of deep fungal infection depends on external factors and the immunity of human body.Recently, in accompany with the wide application of immunosuppressants, broad-spectrum and antineoplastic drugs and so on, especially the immunocompmmized patients dramatically increased and the speading of HIV infections. Meanwhile, following the organ transplantation, urethral catheterization, chemo-theropy for cancer markedly processed, the nosocomial opportunistic systemic fungal infections also markedly increased. Fungal infections of the urinary tract, respiratory tract and invasive fungal infections are increasing in incidence. Caused by a fungal infection was mainly Candida, Aspergillus and Cryptococcus. Candida spp are still the major pathogens of nosocomial fungal infection. But in recent years, great changes have taken place in the type of Candida spp. infection. According to the data of both domestic, Candida albicans infection showed a trend of gradual declined, there is an upward trend of the non-Candida albicans infections.Deep fungal infection in the event of a systemic infection, with high morbidity and mortality. The diagnosis of deep fungal infection is very difficult. On the other hand, even if the diagnosis is clear, also very difficult for the treatment of systemic infection. It is very important for clinical physicians to understand the epidemiology of fungal infections. Accordingly clinical doctors can take effective prevention and control measures in a timely manner.In recent years, the virulence of Candida spp. has been widely concerned. The study about pathogenic mechanism of candida spp. focus on adhesion and invasion, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching, heat shock proteins and so on. Foreign researchers have found that the virulence of Candida spp. may be related to melanin. But the mechanism and related factors still unclear.The production of melanin is associated with the virulence of various microorganisms, such as Aspergillus funigatus-Cyptococcus neoformans、Malassezia、 Blastomycosis and so on. Moreover melanin can resist defense element、antimicrobial peptides and phagocytosis of phagocytes. Melanin can protect organisms from radiation damage, and be used as ultraviolet absorbent, antioxidant and new type of natural drug carrier.For the foreign studies were limited to Candida albicans, and do not include of non-Candida albicans and clinical Candida spp. About the relationship between Candida spp and melanin the domestic has not yet been studied. On the other hand, great changes have taken place in the type of Candida spp infection. To investigate the epidemiological characteristics of nosocomial infection of Candida spp, we collected the 371 cultured strains of Candida spp form Jan.2014 to Oct.2014 and to statistical analysis, to investigate epidemiology of nosocomial infection of Candida spp. Meanwhile,371 clinical identified Candidas spp. caffeic acid, DOPA agars (CT) and minimal medium (MM), in contrast to the Cryptococcus neoformans.In the end, were incubated combine TEM and ESR futher were combined to verificate the relationship between Candida and melanin.1 To clinical investigate of nosocomial infection of Candida spp.1.1 ObjectivesTo understand the epidemiological feature of nosocomial infection of Candida spp, and to provide the experimental evidence for reducing Candida spp. infection.1.2 MethodsTo collect the 371 cultured strains of Candida spp form Jan.2014 to Oct.2014 and to understand the distribution of Candida spp species specimen type, disease category and department distribution et al.1.3 Results(1) Identification of all 371 Candida spp. isolates from patientsCandida albicans accounted for 47.17%(175/371), and non-albicans Candida spp.52.83%(196/371), including Candida tropicalis 19.68%(73/371), Candida glabrata 12.94%(48/371), Candida krusei 7.55%(28/371), Candida parasilosis 7.01%(26/371), other Candida spp.5.66%(21/371).(2) The distribution of all 370 Candida spp. of sexIn all the 371 cases, men affected were moer than women affected, the male ratio was 57.68%(214/371), and the female ratio was 42.05%(156/371), and the difference was no statistically significant (χ2=4.851, P=0.434>0.05)(3) Species distribution and composition of 371 Candida spp.With sputum specimens accounted for 39.08%%(145/371), urine second 19.14% (71/371), blood third 16.71%(62/371), secretion to a minimum 8.63%(32/371), others 12.13%(45/371).(4) The distribution of 371 Candida spp. of ageThe incidence in different age of<20、20～40、40～60、>60 was 3.23%、17.25%、 27.76%.51.75%. With at lease<20 years old, mainly from the>60 years old.(5) Species distribution of 371 Candida spp. form various clinical departmentsThese Candida spp strains were mainly isolated from department of respiratory, general surgery, oncology department, department of neurology etc. The incidence were 30.73%、21.16%、8.36%、5.12% et al.(6) The distribution of 371 Candidas spp of underlying diseasesThe involved organs included respiratory, digestive system, urinary system, trauma and postoperative, nervous system, hematological system, cyclic system and others, with the number of cases 100,93,33,32,29,17,15,52.The respiratory system were isolated the most 26.95% Candidas (100/371).1.4 Conclusions(1) The infection of Candida albicans is descending, but it is still the most common pathogen.(2) In all the 371 cases, men affected were moer than women affected, the difference was no statistically significant.(3) As to infection site, Respiratory tract is most common position, and the following is Urinary tract, Bloodstream. has became the third.(4) The number of top infection department were department of respiration, general surgery, oncology department.(5) The risk factors are as follows:more than 60 years old, blood glucose, plasma bumin usage of broad-Spectrum antibiotics and invading medical operation.2 The relationship between Candida spp. and melanin2.1 ObjectivesTo study the relationship between Candidas spp and melanin by screening the Candidas which can produce melanin.2.2 MethodsIncubate 371 clinical identified Candidas spp and SC5314 by caffeic acid DOPA agars (CT) and minimal medium (MM), in contrast to the Cryptococcu neoformans, combine TEM and ESR futher verification to the relationship between Candida spp and melanin.2.3 Results(1) Melanin productionC.neoforman gave evidence of pigmentation on all agars. On the 5d a standard strain of Candida albicans SC5314 were found producing pigmentation on DOPA agars and minimal medium (MM). On the 10d twelve of the Candidas spp were found producing pigmentation on DOPA agars(CT);fifteen of them were found producing on minimal medium (MM).(2) Transmission electron micrographs of C.neoforman、SC5314 and clinical Candidas spp.The production of melanin by C.neoforman was seen by TEM as increasing numbers of electron-dense clumps located around the periphery. Similar clumps were never observed in SC5314 and clinical Candidas spp.(3) ESR spectrum of C.neoforman and SC5314The production of spectrum of C.neoforman was seen by ESR spectrum. Similarly spectrum were never seen in SC5314 and clinical Candidas spp.2.4 Conclusions(1) According to the results of these medias to illustrate that whether Candida spp produce melain is not reliable enough, these are need to combine TEM and Electron spin resonance (ESR) futher verification.(2) We are still need to continue to further increase the sample and do the same kind of screening. On the other hand, we should be further enzyme linked immunosorbent experiments to verify the melanin.