Differential diagnosis in bloodstream infection with Trichosporon asahii and Geotrichum capitatum / 中国感染控制杂志

Objective To provide reference for establishing diagnosis and differential diagnosis methods of rare yeast-like fungal bloodstream infection for clinical microbiology laboratory.Methods Trichosporon asahii (T.asa-hii)and Geotrichum capitatum (G.capitatum)bloodstream infection was diagnosed and differentially diagnosed through clinical data analysis,morphological examination,biochemical reactions,and molecular biology technology. Results Two types of yeast-like fungal bloodstream infections in case 1 and case 2 both occurred in leukemia agranulocytosis phase after chemotherapy,such infections were serious and highly similar.The cultivated colonies on blood agar plates of case 1 and case 2 were performed gram stain and microscopic examination.Hyphae,arthro-spores and microconidia were visible in the former,thickness of hyphae branches and length of arthrospores were different,most presented rectangular and barrel shape;the latter can be seen hyphae with transparent septum bro-ken up into arthrospores,presented rectangular shape,did not produce blastoconidia.Identification with API 20C AUX showed that they were T.asahii and G.capitatum.The PCR product sequences were compared with NCBI, suggesting that T.asahii and G.capitatum were at sexual stage.Conclusion Comprehensive application of a varie-ty of technical methods is helpful for improving the diagnosis accuracy of bloodstream infection with yeast-like fungi, identifying Trichosporon and Geotrichum to the species level may help physicians to understand such rare fungal in-fection,choose antifungal agents rationally,and improve clinical prognosis.

In vitro susceptibility of Geotrichum silvicola to five antifungal agents and electron microscopic observation of terbinafine-treated Geotrichum silvicola / 中华皮肤科杂志

Objective To evaluate in vitro antifungal activities of five clinically common antifungal agents against Geotrichum silvicola,and to observe morphological changes of Geotrichum silvicola after treatment with terbinafine.Methods Five antifungal agents commonly used in clinic,including terbinafine (TER),amphotericin B (AmB),flucytosine (FC),fluconazol (FCZ) and itraconazole (ICZ),were tested in this study.According to the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 document and relevant literatures,a susceptibility test was performed to determine the minimal inhibitory concentration (MIC) values of the five antifungal agents against G eotrichum silvicola.Scanning electron microscopy (SEM) was used to observe morphological changes of Geotrichum silvicola treated with different concentrations of TER.Results The MIC values against Geotrichum silvicola were as follows:TER,0.01 μg/ml;AmB,0.4 μg/ml;FC,2 μg/ml;FCZ,2.69 μg/ml;ICZ,0.25 μg/ml.Geotrichum silvicola was sensitive to TER,AmB,FC and FCZ,and sensitive to ICZ in a dose-dependent manner.SEM revealed that after TER treatment,the surface of Geotrichum silvicola became rough and shrinking with irregular defects and holes,and even gave a fragment-like appearance.Conclusions Among the five tested antifungal agents,TER shows the strongest activity against Geotrichum silvicola.Within a certain range,the higher the concentration of TER,the more serious the damage to Geotrichum silvicola.

Rare severe mycotic infections in children receiving empirical caspofungin treatment for febrile neutropenia

ABSTRACTEmpirical antifungal therapy is most often given to patients with leukemia. However breakthrough fungal infections under antifungal therapy are not uncommon. Four children, with hematologic malignant disease developed mycotic breakthrough infections while on empirical caspofungin treatment for a median of 14 (range 11-19) days. Trichosporon asahii was detected in the blood culture of two patients and Geotrichum capitatum in the other two (one patient also had positive cerebrospinal fluid culture). Because the patients' clinical situation worsened, voriconazole was empirically added for two patients three and five days before the agent was detected. The first sterile blood culture was obtained 3-7 days of voriconazole treatment. All patients reached clear cultures but one patient died. One patient with central nervous system infection with G. capitatum had severe neurological sequelae. Very severe fungal infections can occur during empirical caspofungin therapy. Therefore, patients should be followed closely.

Invasive infection due to Saprochaete capitata in a young patient with hematological malignancies

We report a case of invasive infection due to Saprochaete capitata in a patient with hematological malignancies after chemotherapy treatment and empiric antifungal therapy with caspofungin. Although severely immunocompromised the patient survived been treated with amphotericin B lipid complex associated with voriconazole.

Pulmonary infection by Geotrichum candidum.

Geotrichosis is a condition caused by Geotrichum candidum. Apart from thrush and superficial bronchial mucosal infection, pulmonary form is the most common. We report a case of pulmonary geotrichosis in an immunocompetent patient from a tertiary care hospital.

Influência do uso de cultura adjunta nas características físico-químicas e sensoriais do queijo tipo Camembert / Effect of the addition of a supplementary culture on the physical physicalchemical and sensory characteristics of Camembert-type cheese

O presente estudo avaliou o efeito da adição do Geotrichum candidum, como cultura adjunta, na aceitação e composição do queijo tipo Camembert. O leite utilizado na fabricação dos queijos foi submetido à pasteurização e adicionado de Lactococcus lactis subsp. Lactis e Lactococcus lactis subsp. cremoris. Foram realizados quatro tratamentos: controle (T1) – sem adição de Geotrichum candidum; e T2, T3 e T4, com concentrações, respectivamente, de 0,5 U, 1 U e 1,5 U do microorganismo. Após 1, 9, 17, 25, 33 e 41 dias de fabricação, os queijos foram avaliados quanto aos parâmetros: acidez, pH, proteína, NS a pH 4,6, NS em TCA12%, umidade, e para gordura e sal no queijo com um dia de preparação. A análise de aceitação foi realizada aos 30 dias de maturação. Os queijos com e sem adição de Geotrichum candidum não diferiram (P > 0,05) nas análises físico-químicas. Os quatros tratamentos diferiram (P < 0,05) em todas as análises no decorrer do tempo de maturação. Com o aumento na concentração do Geotrichum candidum, houve aumento na média de aceitação dos provadores. A utilização do Geotrichum candidum é uma boa alternativa para as indústrias que desejam um produto com boa aceitabilidade e características semelhantes ao tradicional queijo Camembert.

Breeding of high lipid producing strain of Geotrichum robustum by ion beam implantation

To obtain an industrial strain with high lipid yield, the wild strain G0 of Geotrichum robustum was mutated by means of nitrogen ions implantation. Mutagenic effects of strain G0 by low energy N+ ion implantation were studied. The experimental results indicated that the survival rate curve took a "saddle" shape, and the positive mutation rate was increased to 22.00 percent at the dose of nitrogen ions 2.0 x 10(15) ions/cm² when the survival rate was 28.60 percent. By repeated screening, a high lipid producing strain G9 was obtained. The biomass, lipid content and lipid yield of the mutant can reach 40.25 g/L, 71.14 percent and 28.63 g/L after cultured in a 5L fermenter for 8 days, increasing by 52.81 percent, 68.82 percent and 157.93 percent to those of wild strain, respectively. Analysis results on fatty acids composition and relative content by gas chromatography and mass spectrometry showed that the lipid in strain G9 was mainly composed of 16-carbon and 18-carbon fatty acids, including 37.360 percent oleic acid, 23.631 percent palmitic acid, 4.458 percent linoleic acid and 26.465 percent stearic acid. Such compositional features were quite similar to plant oil. Geotrichum robustum strain G9 may be an ideal high lipid producing strain for biodiesel production.

Sequential use of ammonium and leucine as nitrogen sources during growth of Geotrichum candidum on a glucose based medium / Uso secuencial del amonio y leucina como fuentes de nitrógeno durante el crecimiento de Geotrichum candidum en un medio basado en glucosa

Geotrichum candidum growth on ammonium and leucine as nitrogen sources and glucose as a carbon source was examined. A clear preference of G. candidum for ammonium over leucine as a nitrogen source was shown. Indeed, ammonium was completely exhausted at the end of exponential growth after less than 35 hrs of culture; in contrast only 5 percent of leucine was concomitantly assimilated. Growth continued at slower rates on glucose and leucine as carbon and nitrogen sources respectively, and at the end of culture (185 hrs), leucine was completely exhausted.

In vitro hair perforation test for and scanning electron microscopic observation on Geotrichum / 中华皮肤科杂志

Objective To determine the degree of damage to hairs by Geotrichum, and to compare the difference in infection duration and intensity by Geotrichum silvicola isolates from skin lesions and blood and Geotrichum candidumn isolates between hairs from different age groups. Methods In vitro hair perforation test was carried out on the hairs from healthy individuals of different age groups. Scanning electron microscopy was performed to observe hairs perforated by Geotrichum silvicola isolates from skin lesions and blood as well as Geotrichum candidumn isolates. Results Both Geotrichum silvicola and Geotrichum candidumn isolates could perforate hairs. The time taken to perorate hairs was significantly different between isolates of Geotrichum silvicola from skin lesions, blood and Geotrichum candidumn in every age groups (all P ＜ 0.05).The Geotrichum silvicola isolates from blood perforated hairs in the shortest time (range: 53 - 64 days, mean:58.07 ± 3.15 days), followed by those from skin lesions (range: 57 - 66 days, mean: 61.05 ± 2.55 days), and Geotrichum candidumn (range: 61 - 74 days, mean: 67.11 ± 3.78 days). The time taken to perforate hairs by Geotrichum significantly increased with age, and significant difference was observed between hairs from the four age groups, i.e., ＜ 2 years, 2 - 13 years, 14 - 19 yeas, ＞ 19 years, but not between the age group of ＜ 2 years and that of 2 - 13 years (P ＞ 0.05 ). As scanning electron microscopy showed, both Geotrichum silvicola and Geotrichum candidumn could damage hairs, and the degree of damage by Geotrichum silvicola was more severe than that by Geotrichum candidumn. Conclusions The damage to hairs by Geotrichum silvicola is earlier and more severe than that by Geotrichum candidumn. The younger the age, the more liable the hairs to be damaged by Geotrichum.

Screening of microbial lipases and evalutaion of their potential to produce glycerides with high gamma linolenic acid concentration

Gamma-linolenic acid (GLA, 18:3, cis- 6,9,12-octadecatrienoic acid), an important compound in n-6 eicosanoid family biosynthesis, occurs in the lipids of a few plant and microbial sources. This study focused on the screening of microbial strains with suitable lipase activity for enrichment of GLA by selective hydrolysis of the borage oil (21.6 percent of GLA/total fatty acids). Firstly, 352 microrganisms were tested for their lipolytic capacity using screening techniques on agar plates containing borage oil, strains were then selected and screened for their activity (U/mg) using both submerged fermentation (SmF) and solid state fermentation (SSF). The rate of hydrolysis and the selective preference of these hydrolytic enzymes towards fatty acids, with a special focus on enrichment of GLA were studied and compared with those obtained by two commercially-available lipases. Only one of the lipases tested during this study displayed selectivity, discriminating the GLA during the hydrolysis reaction. Using the enzymatic extract from Geotrichum candidum as a biocatalyst of the reaction, it was possible to obtain a percentage of 41.7 percent of GLA in acylglycerols fraction when the borage oil was treated in a fixed-bed reactor for 24 hours at 30ºC.

Optimization of Lipase Production Conditions by Geotrichum candidum Y162 Using Single Factor-response Surface Methodology / 中国生物工程杂志

The fermentation conditions of lipase production by Geotrichum candidum Y162 were optimized. Initially, the most suitable carbon olive oil, nitrogen source soybean flour and NH4Cl, salt BaCl2 and MgCl2 were selected according to single factorial experiments respectively. Based on the result, screening methodology Plackett-Burman design was used to evaluate the effects of twelve factors related to lipase production and three statistically significant factors olive oil, BaCl2 and NH4Cl were selected. The path of steepest ascent was used to approach the optimal region of lipase production subsequently. Then, the optimal combined concentration for maximum enzyme activity were further optimized by response surface methodology and determined as follows: olive oil 2.35%, BaCl2 0.36%,and NH4Cl 4.69%.The optimization of culture conditions of G.candidum Y162 led to a 2.25-fold increase in lipase production relative to initial result 14.16 U/ml, which indicate that single factor in combination with response surface methodology is an effective method for optimization of lipase production conditions by G.candidum Y162.

The use of acetonitrile as the sole nitrogen and carbon source by Geotrichum sp. JR1

A yeast strain identified as Geotrichum sp. JR1 was able to use acetonitrile as the sole carbon and nitrogen source. The strain grew in 0.5 to 2M acetonitrile. Ammonia generation as enzymatic product during the strain growth indicates the presence of an acetonitrile degrading enzyme. Acetic acid and acetamide were detected during assays with the resting cells cultivated in acetonitrile, indicating the presence of nitrile and amide degrading enzymes. This paper is the first to describe the use of acetonitrile as the sole carbon and nitrogen source by a yeast.

Uma linhagem de levedura identificada como Geotrichum sp. JR1 foi capaz de utilizar acetonitrila, em concentrações de 0,5 a 2M, como única fonte de carbono e de nitrogênio. A geração de amônia durante o crescimento do microrganismo indica a presença de sistema enzimático capaz de degradar acetonitrila. Durante os ensaios enzimáticos, com células cultivadas em acetonitrila, foram detectados ácido acético e acetamida como produtos indicando a presença de sistema enzimático capaz de degradar acetonitrila e acetamida. Este trabalho é o primeiro a descrever a utilização de acetonitrila como única fonte de carbono e de nitrogênio por uma levedura.

A case report of toxic epidermal necrolysis associated with geotrichosis due to Geotrichum silvicola / 中华皮肤科杂志

Objective To report a case of toxic epidermal necrolysis associated with geotrichosis due to Geotrichum silvicola. Methods The exudates from the body surface, blood and urine of the patient were examined by microscopy and simultaneously inoculated onto the Sabouraud dextrose agar (SDA) medium. The isolate was examined by microscopy, PCR which amplified the D1/D2 domain of 26S rDNA, and gene sequencing. Homologous sequences were searched in the GenBank/EMBL/DDBJ/PD nucleotide sequence library, and the genetic relationship was analyzed with the genealogical tree. Results Microscopy of pus from the abscess on the dorsa of left hand revealed a lot of spores and a few hyphae, which were not observed in the blood or urine specimens. Meanwhile, whitish colonies were grown in all the three successive cultures of blood and urine specimens, rather than the exudates on the body surface. After itraconazole and garlicin were administered for one week, both microscopic exam and fungus culture were negative. Microscopic exam of the isolate showed arthrospores arranged in chains, budding spores and a few of hyphae. It was found that there was a one-base difference between our isolate (Hebei-1) and the isolate from kerion -like eruptions (Changzheng-1), and a four-base difference between our isolate and the reference Geotrichum silvicola strain as well, in the D1/D2 domain of 26S rDNA. This isolate was identified to be most close to Changzheng-1 in the phylogenetic tree. Conclusion The patient with toxic epidermal necrolysis is associated with geotrichosis due to Geotrichum silvicola.

Kerion Caused by Geotrichum in China: First Case Report in China / 中华皮肤科杂志

Objective To report a case of kerion caused by Geotrichum in China. Methods A 9 year-old-boy had kerion-form lesion on his scalp with swollen posterior auricular lymph nodes, and did not show other definite underlying disease. The pathogenic fungus was identified according to culture, scanning electron microscopy, biochemical tests and DNA sequencing. The hair infection test was performed and the infected hairs were examined by scanning electron microscope. Animal test confirmed the pathogenicity of the fungus. Results The fungal colonies were the same when the tissue cultures were repeated. The colonies showed milky white to yellowish in color. The hyphae could be identified at the periphery on Sabouraud′s agar culture at 27 ℃, which were moist and smooth on the surface at 37 ℃. Under microscope, there were many rectangular arthrospores, round or oval spores with or without buddings, as well as branched hyphae. The isolated fungus was identified as a Geotrichum silvicola by culture, scanning electron microscope, biochemical test and DNA sequencing. The patient′s condition was improved markedly after treatment of terbinafine for 4 weeks. Conclusions This is the first case report of kerion caused by Geotrichum in China, and terbinafine is effective.

Cutaneous Infection by Geotrichum candidum / 대한의진균학회지

Geotrichum(G.) candidum is a common fungus that is rarely pathogenic for man, first described by Link in 1809, and according to Dodge this fungus is classified as a subspecies of Eremnascaeae imperfectae. This species is largely saprophytic and is usually found in soil, decaying matters, and milk product, although isolation from skin, sputum, and feces of man is not unusual. Geotrichosis, caused by G. candidum may occur as an infection of the lung simulating chronic pulmonary tuberculosis or disseminated infection. Very rarely, skin and mucous membrane infection has been documented. These infections usually affect immunocompromised hosts. Literature concerning skin or soft tissue infection with this fungus is limited, especially in immunocompetent persons there are only a few reports by this organism. In this paper we report a case of cutaneous geotrichosis involving skin in a healthy woman, in which case steroid and trauma was supposed to play some roles in the pathogenesis.