Synergistic inhibition of the growth in vitro of Microsporum canis by miconazole and chlorhexidine

An agar dilution technique was used to assess the minimum inhibitory concentrations (MIC) of miconazole, chlorhexidine and a 1:1 combination of both agents for 10 isolates of Microsporum canis. For nine of 10 of the isolates, a combination of miconazole and chlorhexidine was more effective than either agent alone; fractional inhibitory concentration indices indicated a synergistic effect for five isolates and an additive effect for four. These results illustrate the potent antimycotic effect of miconazole and chlorhexidine against M. canis and are in accordance with previous clinical studies that showed the value of using miconazole and chlorhexidine shampoo in association with oral griseofulvin in the treatment of feline dermatophytosis caused by M. canis.     

Efficacy of selamectin in the treatment and control of clinical signs of flea allergy dermatitis in dogs and cats experimentally infested with fleas

OBJECTIVE: To determine whether treatment with selamectin would reduce clinical signs of flea allergy dermatitis (FAD) in dogs and cats housed in flea-infested environments. DESIGN: Randomized controlled trial. ANIMALS: 22 dogs and 17 cats confirmed to have FAD. PROCEDURE: Animals were housed in carpeted pens capable of supporting the flea life cycle and infested with 100 fleas (Ctenocephalides felis) on days -13 and -2 and on alternate weeks with 10 to 20 fleas. On day 0, 11 dogs and 8 cats were treated with selamectin (6 mg/kg [2.7 mg/lb]). Dogs were retreated on day 30; cats were retreated on days 30 and 60. All animals were examined periodically for clinical signs of FAD. Flea counts were conducted at weekly intervals. RESULTS: Throughout the study, geometric mean flea counts exceeded 100 for control animals and were < or = 11 for selamectin-treated animals. Selamectin-treated cats had significant improvements in the severity of miliary lesions and scaling or crusting on days 42 and 84, compared with conditions on day -8, and in severity of excoriation on day 42. In contrast, control cats did not have any significant improvements in any of the clinical signs of FAD. Selamectin-treated dogs had significant improvements in all clinical signs on days 28 and 61, but in control dogs, severity of clinical signs of FAD was not significantly different from baseline severity at any time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical administration of selamectin, even without the use of supplementary environmental control measures and with minimal therapeutic intervention, can reduce the severity of clinical signs of FAD in dogs and cats.     

Studies on the role of carbohydrates in the adherence of Malassezia pachydermatis to canine corneocytes in vitro

A panel of four lectins was used to investigate the role of carbohydrates in the adherence of Malassezia pachydermatis to canine corneocytes in vitro . Pretreatment of canine corneocytes with concanavalin A (10 μg ml⁻¹) inhibited ( P < 0.01) the adherence of one out of six M. pachydermatis strains. This effect was abrogated by pre-incubating concanavalin A with its hapten inhibitor (6% methyl α- d -mannopyranoside), suggesting that mannosyl-bearing carbohydrate residues on the epithelial cells serve as ligands for adhesins expressed by this strain. However, treatment of corneocytes with soybean, wheat germ and gorse lectin, and pretreatment of the yeast cells with either of the four lectins had no reproducible effect on the adherence of two strains.     

POLYARTHRITIS OF PIGS IN WESTERN AUSTRALIA: THE ROLE OF ERYSIPELOTHRIX RHUSIOPATHIAE

A 3-month survey of polyarthritis in pigs was carried out at 3 metropolitan abattoirs in Western Australia. The incidence of total carcass condemnations for polyarthritis was 0.46% and partial condemnation for "arthritis" 1.66% of 15,919 pigs. It was demonstrated that the majority of joint lesions found in either total or partial condemnations were identical pathological conditions, usually differing only in the number of joints involved. Erysipelothrix rhusiopathiae was isolated from the joints of 63% of pigs condemned for polyarthritis; it appears that this organism is the most significant aetiological agent of polyarthritis in Western Australia. The role of mycoplasmas has not been determined. The groww and microscopic lesions seen in affected joints were those of a non-suppurative proliferative polysynovitis. The stifle and elbow joints showed the highest incidence of the most severe lesions. Pigs condemned for polyarthritis over a 6-month period were traced back to 125 farms. Eighty per cent of pigs that had been condemned for polyarthritis had not been vaccinated against erysipelas or were of doubtful vaccination status. Only 3% of pigs had been vaccinated as recommended. The results would suggest that erysipelas vaccine is not directly implicated in the pathogenesis of polyarthritis. The majority of pigs condemned for polyarthritis originated from poorly managed small piggeries run as sideline enterprises. There was no significant pattern to the geographical distribution of polyarthritis cases in Western Australia. Likewise, no significant realtionship was established between polyarthritis condemnations and either breed, sex or bodyweight of thepigs involved.     

Cellular Composition and Viability of Cloned Bovine Embryos Using Exogene-Transfected Somatic Cells

The present study compared the efficiency of transgenic (TG) cloned embryo production by somatic cell nuclear transfer (SCNT) with fetal-derived fibroblast cells (FFCs) which were transfected with pEGFP-N1 to in vitro-fertilized (IVF), parthenogenetic and SCNT counterparts by evaluating the rates of cleavage and blastocyst formation, apoptosis rate at different developmental stages, cell number, ploidy and gene expression in blastocysts. In SCNT and TG embryos, the rates of cleavage and blastocyst formation were significantly lower (p < 0.05) than those of IVF controls, but it did not differ between SCNT and TG embryos. In IVF control, 86.7% embryos displayed diploid chromosomal complements and the rates were significantly (p < 0.05) higher than those of SCNT and TG embryos. Most TG embryos (79%) with FFCs expressed the gene by both PCR and under fluorescence microscopy. The expression of apoptosis by TUNEL was first detected at six to eight cell stages in all embryos of IVF, SCNT and TG groups, but the expression rate at each developmental stages was significantly higher (p < 0.05) in SCNT and TG embryos than in IVF counterparts. The expression rate in inner cell mass (ICM) of TG embryos was significantly higher (p < 0.05) than in SCNT and IVF embryos. These results indicate that the high occurrence of apoptosis observed in SCNT and TG embryos compared with IVF counterparts might influence the developmental competence. Moreover, the SCNT embryos derived using non-transfected donor cells exhibited a lower apoptosis expression in ICM cells than in TG embryos derived using pEGP-N1-transfected donor cells suggesting a possible role of negative gene effect in TG embryos.