Effects of temperature variations and light exposure on the time to growth of dermatophytes using six different fungal culture media inoculated with laboratory strains and samples obtained from infected cats

In this study, 5/6 commercially available fungal culture media were comparable with respect to first growth, first colour change, and first sporulation when inoculated with three strains of Microsporum canis, one strain of Microsporum gypseum, and one strain of Trichophyton species when incubated at either 25°C or 30°C. Five of six plates showed 100% growth at both temperatures. Five of six plates showed 100% growth when inoculated with naturally infective M canis hairs and spores. One commercial product packaged as a self-sealing incubation plate showed growth in only 65.4% of times and the plates were prone to desiccation. M canis inoculated plates were incubated under four different light exposures (24h of light, 24h of dark, 12h light/12h dark, and room lighting) and no differences in growth or sporulation were noted.     

Use of isolated infected spores to determine the sporocidal efficacy of two commercial antifungal rinses against Microsporum canis

In this study, isolated infective Microsporum canis spores were used in an in vitro test model to compare the sporocidal activity of two commercial topical antifungal rinses. The two commercial test solutions used in the study were a lime sulphur solution 97.8% (LymDyp) and miconazole base 5.2%/chlorhexidine gluconate 5.9% mixture (Malaseb Concentrate Rinse). Water and household bleach were used as controls. Isolated infective spores were harvested from infected hairs and 500 microL of the spore suspension was incubated with an equal volume of dilutions of lime sulphur or the miconazole/chlorhexidine gluconate combination for 5 min and 4 h followed by fungal culture. There were too many to count colonies on the water control plates. Lime sulphur was 100% sporocidal at all test dilutions at both times. Miconazole/chlorhexidine gluconate was 100% sporocidal at all but the 1 : 128 dilution after 5 min of incubation and 100% sporocidal when incubated with spores for 4 h. It is not known if the two products have similar antifungal activity against infective spores on or within hairs; however, based on the findings of this study there is good evidence to recommend either rinse as an adjuvant topical therapy in a dermatophyte treatment and control program.     

Efficacy of eight commercial formulations of lime sulphur on in vitro growth inhibition of Microsporum canis

Lime sulphur is a common topical treatment for dermatophytosis in animals. Until recently, a single veterinary lime sulphur formulation was available. The purpose of this study was to compare the efficacy of eight lime sulphur products for in vitro growth inhibition of Microsporum canis using the isolated infected spore model. Infective M. canis spores were isolated from hairs collected from untreated cats. Hairs were macerated in Triton‐X solution and isolated according to a previously published protocol. Equal volumes of spore suspension and lime sulphur solutions were incubated for 5 min and plated onto modified BBL? Mycosel? agar (Becton, Dickinson and Company; Sparks, MD, USA) plates. Five plates were inoculated for each sample solution. Distilled water and bleach were used as controls. Colony forming units were counted daily for 21 days; positive control plates contained >300 colony forming units/plate. Seven of the products were supplied as concentrates and they were tested at the manufacturer’s recommended dilution, twice label concentration and half label concentration. A prediluted product SulfaDip^® (Trask Research, Inc.; Daluca, GA, USA) was tested at the label and half label concentration. All veterinary products formed recommended treatment dilutions of 3% sulphurated lime solution except one (LymDyp^®, IVX Animal Health Inc.; St Joseph, MO, USA), which formed a 2.4% sulphurated lime solution. Results of the study showed complete growth inhibition of M. canis spores by all products at all dilutions tested. These results indicate that all tested lime sulphur‐containing products were equivalent. Field studies are needed to test product equivalency in vivo.     

Use of lime sulphur and itraconazole to treat shelter cats naturally infected with Microsporum canis in an annex facility: an open field trial

Dermatophytosis is the most common contagious and infectious skin disease of cats. It is of particular importance in animal shelters because it is a known zoonosis, highly contagious, and easily transmitted. In this open clinical trial, 58 cats with confirmed Microsporum canis dermatophytosis and 32 uninfected bonded pairs or littermates were treated with a combination of 21 days of oral itraconazole (10 mg kg(-1)) and twice weekly lime sulphur rinses until cured. Cats were not clipped in this treatment programme. Fungal cultures were obtained once weekly on all cats, and cats were considered cured when they had two consecutive negative weekly fungal cultures. Cats were held in the facility and received continued topical treatment until the fungal cultures were finalized. None of the cats developed oral ulcerations as a result of grooming the lime sulphur rinses. Oral ulcerations only developed in cats with clinical signs associated with upper respiratory disease. None of the uninfected cats living in contact with infected cats became culture positive or developed skin lesions. When data were examined retrospectively and the number of days to finalize the cultures was subtracted (21 days) from the total number of days the cats were housed in the annex, the mean number of days of treatment required for cure was 18.4 +/- 9.5 SEM (range 10-49 days). Cats with more severe infections required longer therapy. In this shelter, the combination of oral itraconazole and topical lime sulphur rinses for the treatment of dermatophytosis was effective and safe.     

Use of itraconazole and either lime sulphur or Malaseb Concentrate Rinse® to treat shelter cats naturally infected with Microsporum canis: an open field trial

In an open non‐randomized study, 90 cats with severe dermatophytosis were treated with 21 days of oral itraconazole at 10 mg/kg and one of three topical antifungal rinses applied twice weekly: lime sulphur (LSO); reformulated lime sulphur with an odour‐masking agent (LSR); or a 0.2% miconazole nitrate and 0.2% chlorhexidine gluconate rinse (MC). Weekly examinations and fungal cultures were used to monitor the cats’ response to therapy. If at day 42 of treatment cats were still strongly fungal culture positive and/or developing new lesions, they were retreated with oral itraconazole and LSO. Cats were not prevented from licking the solutions and none developed oral ulcerations. Thirty‐one cats were treated with LSO, 27 with LSR and 32 with MC. The median number of days to cure was 30 (range 10–69 days) and 34 (range 23–80 days) for LSO and LSR, respectively. Thirty‐two cats were treated with MC, and 13 of 32 cats required repeat treatment because of persistent culture‐positive status and development of new lesions. Median number of days of treatment for the 19 cats that cured with MC was 48 (range 14–93 days). When the number of days to cure was compared between the groups, there was a significant difference between cats treated with LSO and LSR (P = 0.029) and cats treated with LSO and MC (P = 0.031), but no significant difference between the number of days to cure for cats treated with LSR and MC (P = 0.91).     

Analysis of Soil Variability Measured With a Soil Strength Sensor

In the context of precision agriculture, the knowledge of soil strength variability at the field scale may be useful for improving site-specific tillage. Moreover, rapid and accurate sensing methods for soil physical properties determination would favourably replace labour-intensive, time-consuming and expensive soil sampling and analysis. This study aims at validating conclusions of a previous study which was conducted to develop and test a soil strength sensor in field conditions. The coupled acquisition of the sensor's signals and the corresponding DGPS positions allowed establishment of maps for the three measured outputs, namely the horizontal force (F _x ), the vertical force (F _z ) and the moment (M _y ). In order to study the relationships between measured forces and soil physical parameters, a series of soil properties were measured on soil cores collected in 10 reference plots. Significant correlations were found between F _x and the average resistance to cone penetration at 25 cm depth (r = 0.95) and between F _x and average soil moisture at 30 cm depth (r = –0.95). These relationships were similar to those found in the first study. This sensing method proved its capability to characterise within-field soil variability.