Analysis of Dermatomycoses in Lanzhou District of Northwestern China

The skin mycoses, perticularly dermatophytoses, in Lanzhou district, Northwestern China, was investigated during July 2002–June 2003. The specimens from patients suspected of having dermatomycoses were examined microscopically in KOH preparations and cultured on Sabouraud dextrose agar (SDA). Among 1443 suspected cases, 594 were KOH positive and 221 cultures of fungi were isolated. The most frequently isolated fungi were Trichophyton rubrum (43.9%) Trichophyton mentagrophytes (29.4%) and Candida species (14.0%). The frequency of tinea pedis, onychomycosis and tinea manuum were 38.7, 27.8 and 13.5%, respectively. In Lanzhou district, tinea pedis is the most commonly seen dermatophytoses, and T. rubrum is the most frequent etiologic agent.     

Updating Corneofungimetry: A Bioassay Exploring Dermatomycoses and Antifungal Susceptibility

Superficial dermatomycoses are frequent conditions in humans and animals. Specific treatment modalities have been designed using a variety of different antifungal compounds. The need for antifungal susceptibility testing (AST) has been growing steadily over the last two decades due to the extending number of newer antifungal agents. Objective inter- and intraindividual comparisons of their respective efficacies are nearly impossible to perform in vivo. Currently, a series of standardized AST methods and interpretative guidelines have been designed. However, their clinical relevance for dermatomycoses is not consistent. The corneofungimetry bioassay was designed to test comparatively a series of antifungals on pathogenic fungi growing on sheets of human stratum corneum. Computerized morphometric assessments bring numerical values allowing statistical comparisons. Variants of corneofungimetry address more specific aspects related to fungal cell adhesion, fungitoxicity and lipid-dependent fungi.     

Ulteriori considerazioni sul meccanismo di azione della Griseofulvina nella terapia delle dermofizie

Summary The Author gives his theory on the mechanism of action of griseofulvin in the process of recovery from dermatomycoses.The concept of an unhabitability of the str. corneum as a sequel of griseofulvin saturation seems to the A. to be unacceptable in the light of the most recent investigations. The antimycotic activity of griseofulvin is not sufficient to explain the therapeutic effect obtainable, and it can only justify the refractoriness to experimental infections in animals and in superinfection in man.In the recovery process from dermatomycoses griseofulvin intervenes as a slowing factor on the progress of the mycoses, adding its effect to the natural expulsive forces of the epidermis and hair structure, and thus, leading to a definite cure.The A. underlines the added value of the non-antimycotic, pharmacologic action of griseofulvin (anti-inflammatory, vascular, pilogenetic), demonstrated by the A. self and by other research workers in the healing process of dermatomycoses.     

Immunochemical characterization of somatic and metabolic antigens of 4 species of Aphanoascus : Preliminary results

Aphanoascus spp. are keratinophylic fungi occasionally described as etiological agents of tinea-like dermatomycoses. The goal of this work was to immunochemically characterize somatic and metabolic soluble antigens prepared from 4 species of Aphanoascus. Electrophoresis in SDS-PAGE gel and immunoblotting with sera from rabbits experimentally immunized with both somatic and metabolic antigens have shown a similar pattern among the species analyzed. However, some differences were noted between the species of Aphanoascus. These results suggest the existence of species-specific antigens. This revised version was published online in June 2006 with corrections to the Cover Date.     

Frecuencia de dermatofitos en una muestra de felinos del área urbana del Gran Mendoza,Argentina

BackgroundThe cat, considered the main reservoir of Microsporum canis, lives in urban areas, and also plays an important role in the emergence of dermatomycoses.AimsTo determine and analyse the frequency of zoonotic dermatophytes in a sample of cats in an urban area of the Gran Mendoza region.MethodsThe animals selected were household cats and cats less than one year old that came from shelters and kennels from urban areas in the Gran Mendoza region. A total of 45 samples from cats with and without dermatological lesions were analysed. These samples were collected through skin scraping, hair removal and Mackenzie brush, respectively. Direct observation was made with KOH and glycerol after heat exposure. Samples were cultured on Sabouraud and Lactrimel agar slants with chloramphenicol and cycloheximide for 30 days.ResultsThe frequency of dermatophytes isolated in this preliminary study was 13.3%. There were not statistically significant differences by source, age, sex, race or dermatological condition. Zoonotic dermatophytes were found in 2 household cats out of the 21 that had direct contact with children or the elderly. M. canis was isolated in 83.3% cases.ConclusionsThe frequency of isolation of zoonotic dermatophytes in the sample of cats in an urban area of the Gran Mendoza region was 13.3%, a value higher than expected. M. canis was the most isolated species.     

In vitro susceptibility of dermatomycoses agents to six antifungal drugs and evaluation by fractional inhibitory concentration index of combined effects of amorolfine and itraconazole in dermatophytes

To investigate the antifungal drug susceptibility of fungi responsible for dermatomycoses, minimum inhibition concentration (MIC) tests were performed in 44 strains of dermatophytes, including Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton verrucosum, Trichophyton tonsurans, Microsporum canis, Microsporum gypseum and Epidermophyton floccosum, with six antifungal drugs (amorolfine, terbinafine, butenafine, ketoconazole, itraconazole and bifonazole) by broth microdilution assay according to Clinical Laboratory Standard Institute protocols. Six possible dermatomycosis‐causing non‐dermatophytic fungi were also tested. The two major causes of tinea, T. rubrum and T. mentagrophytes, showed significantly different sensitivities to ketoconazole and bifonazole. Clinically derived dermatophytes were sensitive to the six antifungal drugs tested. However, non‐dermatophytes, especially Fusarium spp., tended to be resistant to these antifungal drugs. In Trichophyton spp., the MICs of non‐azole drugs had narrower distributions than those of azoles. To evaluate the effects of antifungal drug combinations, the fractional inhibitory concentration index was calculated for the combination of amorolfine and itraconazole as representative external and internal drugs for dermatophytes. It was found that this combination had synergistic or additive effects on most dermatophytes, and had no antagonistic effects. The variation in susceptibility of clinically derived fungal isolates indicates that identification of causative fungi is indispensable for appropriately choosing effective antifungal drugs in the early stages of infection. The results of combination assay suggest that multiple drugs with different antifungal mechanisms against growth of dermatophytes should be used to treat refractory dermatomycoses, especially onychomycosis.     

Comparison of the efficacy of 1% flutrimazole cream twice a day with 1% flutrimazole cream once a day for the treatment of superficial dermatophytoses

Different clinical studies have demonstrated flutrimazole's efficacy in the treatment of superficial dermatomycoses when administered either twice daily or once daily for four weeks. The aim of the present study was to compare both dosing schedules for the treatment of superficial dermatomycoses. In this randomized, controlled, double blind study, we included 84 patients suffering superficial dermatophytosis (confirmed by microscopic examination (KOH) and culture) susceptible for topical monotherapy. Forty-one patients received flutrimazole 1% twice daily (TD) and forty-three once daily (OD) for four weeks. The efficacy of treatment was evaluated by clinical and mycological criteria at the end of treatment (D28) and after four weeks without treatment (D58). Clinical and mycological cure rates on D28 were 50% with TD and 65% with OD treatment. Only considering clinical evaluation, clinical cure rates on D28 were 63% (TD) and 70% (OD). Also, clinical and mycological cure rates on D56 were 65% with TD and 72% with OD treatment. Only considering clinical evaluation, clinical cure rates on D56 were of 68% (TD) and 72% (OD). The overall tolerability was similar in both treatment groups. The efficacy assessment at the end of treatment (D28) and four weeks after treatment discontinuation (D56) showed that the OD treatment is not inferior to the TD treatment, with similar clinical and mycological cure rates and clinical cure rates in both cases. The OD administration of flutrimazole cream 1% is the most appropriate dosing schedule as it provides the same efficacy, it improves patient's compliance and the cost per day of treatment.     

New Quantitative, Qualitative, and Confirmatory Media for Rapid Analysis of Food for Clostridium perfringens

A selective and differential medium, Shahidi-Ferguson Perfringens agar (SFP agar), and a confirmatory medium, lactose-motility agar (LM agar), were developed for the enumeration and identification of Clostridium perfringens in foods. These media provide a rapid, specific, and direct diagnosis of C. perfringens. SFP agar contains sodium metabisulfite and ferric ammonium citrate to demonstrate H(2)S production and egg yolk to demonstrate lecithinase production by C. perfringens. On SFP agar, C. perfringens produces black colonies, 2 to 3 mm in diameter, surrounded by zones of opaque precipitate. The typical colonies are confirmed on LM agar. Enumeration and identification are completed within 48 hr. All of the ingredients of SFP agar are stable to heat and storage conditions. SFP agar also contains two antibiotics, kanamycin and polymyxin B, which are inhibitory to many bacteria commonly occurring in foods. A comparative study of SFP agar and noninhibitory media showed that SFP agar did not inhibit any of the 16 strains of C. perfringens tested. Recovery of C. perfringens added to foods averaged 90.6% for SFP agar as compared with 69.8% for sulfite polymyxin-sulfadiazine (SPS) agar (BBL) and 60.2% for SPS agar (Difco). The colonies on the SFP agar, were much larger and were consistently black. Of 464 food samples tested, C. perfringens was found in 27 samples with SFP agar and in 5 samples with SPS agar (Difco), with a recovery ratio considerably higher on SFP agar. SFP agar is a more specific presumptive medium for the enumeration of C. perfringens and in conjunction with LM agar should save considerable time, effort, and materials toward the final identification of the species.     

Oxidase testing from Kligler's iron agar and triple sugar iron agar slants

Many members of the familyVibrionaceae have been implicated as causative agents of diarrhea. Most of these organisms are non-lactose fermenters, and all are oxidase-positive. If the oxidase test could be reliably performed on growth from the surface of Kligler's iron agar and/or triple sugar iron agar slants, it would aid in the screening of potential stool pathogens. Forty-six isolates from the generaAeromonas, Plesiomonas, andVibrio were inoculated onto Kligler's iron agar and triple sugar iron agar slants, incubated overnight, and tested for oxidase activity. All 46 isolates produced alkaline over acid, with or without gas, Kligler's iron agar slants and were oxidase-positive. On triple sugar iron agar slants, 13 isolates produced these same patterns, and all were oxidase-positive. Acid over acid, with gas, triple sugar iron agar slants were produced by 18 isolates, and all were oxidase-positive. Acid over acid, without gas, triple sugar iron agar slants were produced by 15 isolates, and all were oxidase-negative. These negative oxidase tests were due to low pH. Oxidase tests performed from the surface of Kligler's iron agar and triple sugar iron agar slants used to screen stool isolates were reliable, provided the slants were acid over acid with gas, or alkaline over acid with or without gas. Kligler's iron agar is recommended with this procedure, since most potential stool pathogens of both theEnterobacteriaceae and theVibrionaceae will produce an alkaline over acid, with or without gas, slant, and false negative oxidase tests will be minimized.     

The effects of agar concentration on the growth and morphology of submerged colonies of motile and non-motile bacteria

The growth and morphology of submerged bacterial colonies was investigated. Five separate colonial forms were recognized depending both on species and on agar concentration. These were (i) branched, dendritic structures seen only with Bacillus cereus ; (ii) lenticular colonies for all other species at high agar concentrations; (iii) small lobed to spherical colonies for non-motile organisms at low agar concentrations; (iv) and (v) large diffuse spherical colonies which can be further subdivided into 'snowball' or 'wispy' types for motile bacteria growing at agar concentrations below about 0·65% w/v. Viable count determinations suggested that agar concentration had little effect in the early stages of growth but that motile cells at low agar concentrations achieved higher cell numbers than did those in concentrations greater than 0·65% w/v. Transmission electron microscopy indicated that bacteria in lenticular colonies were tightly packed within lens-shaped splits in the agar whilst at low agar concentrations motile cells were well separated and appeared to move through the agar matrix.     

Effects of phosphate and nitrate supply on productivity,agar content and physical properties of agar ofGracilaria strain G-16S

Gracilaria strain G-16S was cultured in various phosphorus (P) supply rates with low or high nitrogen (N) supply to determine the effects of nutrient supply on its productivity, agar content and physical properties of the agar. Productivity was reduced after four weeks of growth in zero P supply as plants reached 0.07% P tissue content (critical level), with fragmentation of these plants by six weeks (0.05% P; minimum viable level). Native agar content was higher in low P and high N, or low N conditions. Agar content appeared to increase with decreasing P under high N supply. This increase was not apparent with alkali treatment prior to extraction. Agar gel strength was greatly increased by alkali treatment. The highest gel strengths were obtained under high N supply at all P supply rates except zero P, and under low N supply at 12 M P week^–1. Native agar gel strengths showed a similar pattern on a lower scale. Melting temperatures were higher in agars with higher gel strengths. Dynamic gelling temperatures were generally high for alkali-treated agar, with agar from plants grown in zero P supply showing a slightly elevated gelling temperature. Melting and gelling temperatures of native agars with the highest gel strengths were in the same range as bacteriological agar. These results show that P and N supply affects productivity, agar content and agar physical properties, but the tradeoffs between a slightly higher agar quantity under nutrient limitation and higher agar quality under nutrient-replete conditions seem to favor the latter.     

Volatile metabolites and other indicators of Penicillium aurantiogriseum growth on different substrates.

Penicillium aurantiogriseum Dierckx was cultivated on six agar substrates (barley meal agar, oat meal agar, wheat meal agar, malt extract agar, Czapek agar, and Norkrans agar) and on oat grain for 5 days in cultivation vessels provided with an inlet and an outlet for air. Volatile metabolites produced by the cultures were collected on a porous polymer adsorbent by passing an airstream through the vessel. Volatile metabolites were collected between days 2 and 5 after inoculation. CO2 production was simultaneously measured, and after the cultivation period ergosterol contents and the numbers of CFU of the cultures were determined. Alcohols of low molecular weight and sesquiterpenes were the dominant compounds found. During growth on oat grain the production of 8-carbon alcohols and 3-methyl-1-butanol was higher and the production of terpenes was lower than during growth on agar substrates. The compositions of the volatile metabolites from oat grain were more similar to those from wheat grain, which was used as a substrate in a previous investigation, than to those produced on any of the agar substrates. Regarding the agar substrates, the production of terpenes was most pronounced on the artificial substrates (Czapek agar and Norkrans agar) whereas alcohol production was highest on substrates based on cereals. The production of volatile metabolites was highly correlated with the production of CO2 and moderately correlated with ergosterol contents, whereas no correlation with the numbers of CFU was found. Thus, the volatile metabolites formed and the ergosterol contents of fungal cultures should be good indicators of present and past fungal activity.     

Volatile metabolites and other indicators of Penicillium aurantiogriseum growth on different substrates

Penicillium aurantiogriseum Dierckx was cultivated on six agar substrates (barley meal agar, oat meal agar, wheat meal agar, malt extract agar, Czapek agar, and Norkrans agar) and on oat grain for 5 days in cultivation vessels provided with an inlet and an outlet for air. Volatile metabolites produced by the cultures were collected on a porous polymer adsorbent by passing an airstream through the vessel. Volatile metabolites were collected between days 2 and 5 after inoculation. CO2 production was simultaneously measured, and after the cultivation period ergosterol contents and the numbers of CFU of the cultures were determined. Alcohols of low molecular weight and sesquiterpenes were the dominant compounds found. During growth on oat grain the production of 8-carbon alcohols and 3-methyl-1-butanol was higher and the production of terpenes was lower than during growth on agar substrates. The compositions of the volatile metabolites from oat grain were more similar to those from wheat grain, which was used as a substrate in a previous investigation, than to those produced on any of the agar substrates. Regarding the agar substrates, the production of terpenes was most pronounced on the artificial substrates (Czapek agar and Norkrans agar) whereas alcohol production was highest on substrates based on cereals. The production of volatile metabolites was highly correlated with the production of CO2 and moderately correlated with ergosterol contents, whereas no correlation with the numbers of CFU was found. Thus, the volatile metabolites formed and the ergosterol contents of fungal cultures should be good indicators of present and past fungal activity.     

Nontoxic and durable salt bridges using hydroxyethylmethacrylate hydrogels

Polyhydroxyethylmethacrylate polymers (poly-HEMA) form hydrogels that provide an excellent alternative to agar in the production of salt bridges for use in bioelectrochemical experiments. A method for the simple production of poly-HEMA salt bridges is described. The poly-HEMA bridges were compared with agar bridges of similar geometry. Whereas poly-HEMA salt bridges have a conductivity that is 20 times lower than that of agar bridges of a similar geometry, poly-HEMA bridges are capable of dissipating twice the power compared with agar bridges. The mechanical properties of the poly-HEMA bridges make them easy to manufacture, store, and sterilize. When agar bridges were compared with poly-HEMA bridges in long-term cell culture experiments, the failure rate of the agar bridges was found to be approximately 10% per week vs. a virtually nonexistent failure rate for the poly-HEMA bridges. Because poly-HEMA salt bridges are reliable, durable, and nontoxic to cells, they are a practical alternative to agar salt bridges in certain experimental designs.     

Comparison of Media for Direct Isolation and Transport of Shigellae from Fecal Specimens

Xylose-lysine-deoxycholate (XLD) agar, SS agar, and MacConkey agar for isolating shigellae from fecal specimens were compared. XLD agar was superior to both SS agar and MacConkey agar for isolating Shigella sonnei, and both XLD and SS agar were superior to MacConkey agar for isolating S. flexneri. Direct plating of the fecal specimens in the field resulted in a greater yield of shigellae as compared to transporting specimens to the laboratory either in holding media or enrichment broth. Buffered glycerol saline was superior to other transport media evaluated, yielding 83% of shigella isolates when plated within 48 hr as compared to direct plating. The combination of XLD agar and SS agar is recommended for direct isolation of shigellae, and, whenever possible, these solid media should be taken to the bedside and inoculated directly.     

New medium for the simultaneous detection of total coliforms and Escherichia coli in water.

A new membrane filter agar medium (MI agar) containing a chromogen, indoxyl-beta-D-glucuronide, and a fluorogen, 4-methylumbelliferyl-beta-D-galactopyranoside, was developed to simultaneously detect and enumerate Escherichia coli and total coliforms (TC) in water samples on the basis of their enzyme activities. TC produced beta-galactosidase, which cleaved 4-methylumbelliferyl-beta-D-galactopyranoside to form 4-methylumbelliferone, a compound that fluoresced under longwave UV light (366 nm), while E. coli produced beta-glucuronidase, which cleaved indoxyl-beta-D-glucuronide to form a blue color. The new medium TC and E. coli recoveries were compared with those of mEndo agar and two E. coli media, mTEC agar and nutrient agar supplemented with 4-methylumbelliferyl-beta-D-glucuronide, using natural water samples and spiked drinking water samples. On average, the new medium recovered 1.8 times as many TC as mEndo agar, with greatly reduced background counts (< or = 7%). These differences were statistically significant (significance level, 0.05). Although the overall analysis revealed no statistically significant difference between the E. coli recoveries on MI agar and mTEC agar, the new medium recovered more E. coli in 16 of 23 samples (69.6%). Both MI agar and mTEC agar recovered significantly more E. coli than nutrient agar supplemented with 4-methylumbelliferyl-beta-D-glucuronide. Specificities for E. coli, TC, and noncoliforms on MI agar were 95.7% (66 of 69 samples), 93.1% (161 of 173 samples), and 93.8% (61 of 65 samples), respectively. The E. coli false-positive and false-negative rates were both 4.3%. This selective and specific medium, which employs familiar membrane filter technology [corrected] to analyze several types of water samples, is less expensive than the liquid chromogen and fluorogen media and may be useful for compliance monitoring of drinking water.     

Culture medium for selective isolation and enumeration of Gram-negative bacteria from ground meats.

We developed a new medium, designated peptone bile amphotericin cycloheximide (PBAC) agar, which contains (per liter) 10 g of peptone, 300 mg of bile salts, 1 mg of amphotericin B, 1 g of cycloheximide, and 15 g of agar. When 21 samples of fresh ground beef were studied and plate count agar counts were used as references, we obtained a mean recovery of 28% of total counts with violet red bile agar overlay, whereas we obtained 48% recovery with PBAC agar. With 12 samples of frozen ground beef, recovery on violet red bile agar overlay was 29% of the recovery on plate count agar, whereas the corresponding value on PBAC agar was 45%. PBAC agar allowed the enumeration of 1.4 times as many gram-negative bacteria as violet red bile agar overlay. None of eight strains of gram-positive bacteria and none of eight strains of yeasts grew on PBAC agar. Of 158 colonies randomly selected from pour plates of eight fresh ground meat samples, 95% stained gram negative. In comparison, only 70% of 151 colonies selected from corresponding plate count agar plates were gram negative. The lack of background color, turbidity, and ease of use make PBAC agar easier to handle than other media used for gram-negative bacteria, such as violet red bile agar, violet red bile agar overlay, and crystal violet tetrazolium agar. In the preparation PBAC agar, all ingredients are autoclaved together except amphotericin B, which is filter sterilized and added before the plates are poured.     

Comparative studies on the conformational change and aggregation behavior of irradiated carrageenans and agar by dynamic light scattering

The conformational associative properties of kappa-, iota-, and lambda-carrageenan and agar with irradiation dose were studied by dynamic light scattering. The random scission of the carrageenans and agar by gamma irradiation resulted in the formation of polydispersed lower molecular weight fragments. At high doses, the system moves towards uniformity. Conformational change from coil to helix was observed in all carrageenans and agar at doses up to 100 kGy. The conformational change in lambda-carrageenan may be due to the irregular and hybrid structure of this polysaccharide. Only agar and lambda-carrageenan still undergo conformational transition at a high dose of 200 kGy. Gelation is observed for kappa-, iota-carrageenan up to a dose of 50 kGy while gelation is still observed at 100 kGy for agar. Increase in the hydrodynamic radius with decreasing temperatures for the non-irradiated carrageenans follows this order: lambda-carrageenan>kappa-carrageenan>iota-carrageenan. Slight increases in hydrodynamic radius were observed with irradiation.     

An evaluation of straw-extract agar media for the growth and sporulation of Madurella mycetomatis

Four new media, namely Wheat straw extract agar, Bajra straw extract agar, Jowar straw extract agar and Paddy straw extract agar, were evaluated for their potential to stimulate the growth and sporulation of Madurella mycetomatis in comparison with the conventional Sabouraud dextrose agar and Soil extract agar. Vegetative growth of M. mycetomatis on the four types of Straw extract agars was superior to that obtained on Sabouraud dextrose agar. Isolates of M. mycetomatis sporulated better and faster on the Straw extract agars than on the Sabouraud dextrose agar and Soil extract agar. Straw extract agar is recommended as a sporulation medium for M. mycetomatis. It may prove useful especially for studies of the conidium ontogeny of the fungus for elucidating its taxonomic status.     

Comparison of fluorescent gentamicin-thallous-carbonate and KF streptococcal agars to enumerate enterococci and fecal streptococci in meats.

Two selective and differential media were compared for their abilities to enumerate enterococci and fecal streptococci in pork, beef, and poultry products. Counts obtained on KF streptococcal (KF) agar were compared with counts obtained on fluorescent gentamicin-thallous-carbonate (fGTC) agar. Reactions of 13 known enterococcal species were also observed. All 13 species of enterococci as well as Streptococcus bovis and Streptococcus equinus grew equally well on fGTC agar. KF streptococcal medium allowed growth of most species of enterococci but not S. bovis and S. equinus. Quantitative comparisons between the two media inoculated with pure cultures of known species of enterococci revealed equivalent plate counts following incubation. However, when meat samples were plated, counts on fGTC agar were consistently and significantly higher than counts on KF agar for all sample sources.