Variation in cultural, morphological, biochemical properties and infectivity of Australian isolates of Dermatophilus congolensis

Ellis, T.M.; Masters, Anne M.; Sutherland, S. S.; Carson, J. M.; Gregory, A.R.

doi:10.1016/0378-1135(93)90077-k

Cited by 20 publications

(17 citation statements)

References 17 publications

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“…The lack of fluorescent-antibody staining with monoclonal antibody 2F4 indicates that the chelonid isolates lack a characteristic D. congolensis cell wall antigen. The poor motility and low number of flagella on the zoospores of the chelonid Dermatophilus isolates which we observed contrasted with the characteristics of most mammalian D. congolensis strains examined (9). It is possible that the chelonid isolates express flagella and exhibit greater motility under culture conditions different from the conditions used in this study.…”

Section: Discussioncontrasting

confidence: 58%

“…The rapid resolution of lesions (by 7 days) observed with the chelonid Dermatophilus isolates on three mammalian species differs from the resolution of lesions observed with mammalian D. congolensis strains, which produce lesions that are most severe at days 5 and 7 on guinea pigs and rabbits, respectively, and at days 12 to 14 on sheep (9). This may be due to the slower growth of the chelonid isolates at higher temperatures and adaptation to chelonid hosts.…”

Section: Discussionmentioning

confidence: 75%

“…Isolates were screened for various enzyme activities by using a gel diffusion technique (9), as follows. Suspensions of zoospores in peptone water were prepared from caseous or mucoid growth harvested from cultures on bovine blood agar after 2-4 days of incubation at 27°C (12,24).…”

mentioning

confidence: 99%

“…Restriction enzyme analysis with ApaI, BamHI, and PvuII was performed as described by Sambrook et al (27). These restriction enzymes were chosen because they differentiated groups of D. congolensis isolates in other studies (9,34). Digests were electrophoresed in 0.7% Ultra pure DNA grade agarose (Bio-Rad Laboratories) in Tris-borate-EDTA buffer at 2.7 V/cm for 4 h. The gels were stained with a solution containing 0.1 pg of ethidium bromide per ml and were photographed with Polaroid type 667 film under UV light.…”

mentioning

confidence: 99%

“…A nonhierarchial cluster analysis was carried out to group the isolates into virulence categories for each animal species, as described previously (9).…”

mentioning

confidence: 99%

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Dermatophilus chelonae sp. nov., Isolated from Chelonids in Australia

Masters

Ellis

Carson

et al. 1995

International Journal of Systematic Bacteriology

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Three isolates of a previously undescribed Dermatophilus sp. obtained from chelonids (two strains obtained from turtles and one strain obtained from a tortoise) were compared with 30 Dermatophilus congolensis isolates obtained from Australian mammals. The microscopic appearance, the colony morphology, and most biochemical test results for the chelonid isolates were characteristic of the genus Dermatophilus. Our isolates differed from the mammalian D. congolensis isolates in a number of cultural characteristics, including faster growth at 27°C than at 37"C, formation of two hemolysis zones around colonies on blood agar at 37°C in the presence of 10% CO,, poor motility, and production of a distinctive odor. The DNA restriction enzyme digestion and protein electrophoresis patterns of our strains were distinct. The electrophoretic mobilities of 11 enzymes differed from the mobilities observed with D. congolensis strains. A monoclonal antibody to a surface antigen of an ovine isolate did not react with zoospores or filaments of the chelonid isolates. Biochemical differences between our isolates and D. congolensis included the ability of the chelonid isolates to reduce nitrate to nitrite and the fact that the chelonid isolates exhibit collagenase activity in vitro. We propose that the chelonid isolates should be placed in a new species, Dermatophilus chelonae. Strain W16, which was isolated from a nose scab on a snapping turtle, is the type strain; a culture of this strain has been deposited in the American Type Culture Collection as strain ATCC 51576.A skin disease caused by the actinomycete Dermatophilus congolensis affects a wide variety of animal species and occurs throughout the world. This disease is economically important in cattle in tropical regions and in sheep in high-rainfall areas. Dermatophilosis lesions have also been found in goats, horses, deer, gazelles, giraffes, foxes, chamois, Columbian ground squirrels, cottontail rabbits, owl monkeys, polar bears, seals, pigs, and humans (13). To date, there apparently have been no reports of isolations of D. congolensis from chelonids, although the organism has been isolated from lizards (2,23,30). It has been reported that there is considerable variation in the colony morphology and cultural characteristics of D. congolensis (12). Significant variations in serological, biochemical, and virulence characteristics within the species have also been documented (1,8,10,12,16,18,19,21,33). A study of the variations in the cultural, biochemical, and morphological properties of Australian mammalian isolates of D. congolensis was recently undertaken (9). In our study we compared the properties of three isolates obtained from chelonids with the properties of these mammalian D. congolensis isolates. MATERIALS AND METHODSBacterial isolates. Dermatophilus sp. isolates were obtained from an abscess in a tortoise in 1980 (isolate WS), from skin lesions on a turtle in 1982 (isolate Wll), and from a nose scab on a snapping turtle in 1987 (isolate W16= [T = type strain]); all of...

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Section: Discussioncontrasting

confidence: 58%

Section: Discussionmentioning

confidence: 75%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…A nonhierarchial cluster analysis was carried out to group the isolates into virulence categories for each animal species, as described previously (9).…”

mentioning

confidence: 99%

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Dermatophilus chelonae sp. nov., Isolated from Chelonids in Australia

Masters

Ellis

Carson

et al. 1995

International Journal of Systematic Bacteriology

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The pathogenesis of dermatophilosis

Ambrose

1996

Trop Anim Health Prod

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Pathogen, host and environmental factors must be considered in order to understand the pathogenesis of dermatophilosis. A frequently cited sequence of events involves physical damage to the skin, bacterial multiplication in the epidermis, repeated cycles of invasion by hyphae, infiltration by neutrophils and exudate, regeneration of epidermis and reinvasion. This paper is concerned with pathogen driven mechanisms involved in the origin and development of Dermatophilus congolensis infections. Primary infections of calves under controlled conditions at clipped, cleaned, defatted sites result in characteristic dermatophilosis crusts, illustrating that D. congolensis itself is pathogenic. Calves infected in this way develop protective immune responses to subsequent infections. In contrast first and second infections of calves simultaneously infested with Amblyomma variegatum result in more severe lesions that take significantly longer to heal than lesions on tick free calves. Immunity to D. congolensis is isolate specific, however the antigens that elicit immunity have not been defined, they might include pathogenic or virulence factors. Hyphae are the life-cycle stage most closely associated with the living epidermis. During in vitro growth hyphae secrete antigens and proteolytic enzymes into culture medium. Proteolytic activity has been linked to virulence of D. congolensis. The characteristics of proteases released into culture medium varies between isolates. This raises the possibility that proteases, with as yet undefined functions, act as pathogenic and virulence factors, that they are the targets for protective immune responses and that A. variegatum infestation interferes with host immune responses that normally inhibit their activity.

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Bacterial diseases of skin

Meyer-Rohn¹

2007

Jubb, Kennedy &Amp; Palmer's Pathology of Domestic Animals

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Variation in cultural, morphological, biochemical properties and infectivity of Australian isolates of Dermatophilus congolensis

Cited by 20 publications

References 17 publications

Dermatophilus chelonae sp. nov., Isolated from Chelonids in Australia

Dermatophilus chelonae sp. nov., Isolated from Chelonids in Australia

The pathogenesis of dermatophilosis

Bacterial diseases of skin

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