Amycolatopsis kentuckyensis sp. nov., Amycolatopsis lexingtonensis sp. nov. and Amycolatopsis pretoriensis sp. nov., isolated from equine placentas.

Actinomycete strains isolated from lesions on equine placentas from two horses in Kentucky and one in South Africa were subjected to a polyphasic taxonomic study. Chemotaxonomic and morphological characteristics indicated that the isolates are members of the genus AMYCOLATOPSIS: On the basis of phylogenetic analysis of 16S rDNA sequences, the isolates are related most closely to Amycolatopsis mediterranei. Physiological characteristics of these strains indicated that they do not belong to A. mediterranei and DNA relatedness determinations confirmed that these strains represent three novel species of the genus Amycolatopsis, for which the names Amycolatopsis kentuckyensis (type strain, NRRL B-24129(T)=LDDC 9447-99(T)=DSM 44652(T)), Amycolatopsis lexingtonensis (type strain, NRRL B-24131(T)=LDDC 12275-99(T)=DSM 44653(T)) and Amycolatopsis pretoriensis (type strain, NRRL B-24133(T)=ARC OV1 0181(T)=DSM 44654(T)) are proposed.

Pasteurella testudinis associated with respiratory disease and septicaemia in leopard (Geochelone pardalis) and other tortoises in South Africa.

The first recorded isolates of Pasteurella testudinis from South African tortoises kept in captivity is presented. P. testudinis was found in association with respiratory disease in affected animals.

Collection of preputial material by scraping and aspiration for the diagnosis of Tritrichomonas foetus in bulls.

Two trials were carried out to assess the diagnostic sensitivity and practicability of preputial scraping as a method of collecting preputial material from bulls infected with Tritrichomonas foetus. In the 1st trial, preputial material was collected by simultaneous scraping and aspiration from 3 infected and 1 uninfected bull 10 times over a 5-week period. In the 2nd trial, samples from 5 infected bulls were collected by both sheath washing and scraping on 6 occasions, while 8 uninfected animals were sampled 3 times. Samples were cultured using a modified Trichomonas culture medium (Oxoid). In the first trial, 29 of 30 samples from infected bulls were found to be positive. In the second trial, 83 % of samples collected by both methods tested positive. In neither trial were any samples from the control bulls found to be positive. Scraping was found to be quick and safe, and offered advantages over preputial washing in that urine contamination was easily avoided, samples were smaller and more concentrated and contamination was reduced. It may, however, be subject to greater operator variability than sheath washing. It is concluded that preputial scraping is as effective as washing and represents a suitable alternative for the collection of material for direct examination and culture of Tritrichomonas foetus.

Prevalence of virulent Rhodococcus equi in isolates from soil collected from two horse farms in South Africa and restriction fragment length polymorphisms of virulence plasmids in the isolates from infected foals, a dog and a monkey.

The prevalence of virulent Rhodococcus equi in soil isolates from two horse farms in South Africa and nine clinical isolates from six foals, a foal foetus, a dog, and a monkey was investigated. The isolates were tested for the presence of virulence plasmid DNA and 15- to 17-kDa antigens by immunoblotting. Rhodococcus equi was isolated from almost all of the soil samples obtained from the two farms with 5.0 x 10(1) to 3.3 x 10(4) colony forming units per gram of soil. Virulent R. equi was isolated from three soil samples from one of the farms and appeared in 3.8% (three of 80 isolates), but not in any of the 182 isolates from the other farm. Of the three virulent R. equi isolates, one contained an 85-kb type I plasmid and two an 87-kb type I plasmid. Of nine clinical isolates from the foals, foal foetus, dog and monkey, five from the foals were virulent R. equi which expressed the virulence-associated antigens and contained a virulence plasmid 85-kb type I, and were all isolated from cases of pneumonia typical of that induced by R. equi in young foals living in widely separated areas in South Africa. The isolates from the other four foals, the dog and the monkey were avirulent R. equi.

Evaluation of two PCR-based procedures for typing Clostridium perfringens.

Two polymerase chain reaction (PCR)-based procedures for typing Clostridium, perfringens, which affects most domestic animals, were compared and evaluated for efficiency as substitute to the guinea-pig intradermal test routinely used in our laboratory, namely a multiplex PCR and a protocol based on the individual amplification of gene sequences specific for each toxin. Reference isolates of C. perfringens types A, B, C and D as well as cultures from clinical specimens were tested. The sensitivity and specificity of the PCR was confirmed on reference isolates. There was similarity in results on 43 of the 46 samples typed by all 3 methods. Clear results were obtained by PCR on 5 clinical samples that showed either equivocal or weak skin reactions in guinea-pigs. The multiplex PCR protocol, in combination with the evaluation of bacterial growth, is a better alternative to in vivo toxin typing, since C. perfringens can only be incriminated as cause of a disease when it is present in large numbers in the intestine.

Aerobic intestinal flora of wild-caught African dwarf crocodiles Osteolaemus tetraspis.

Intestinal contents were collected from wild-caught African dwarf crocodiles (Osteolaemus tetraspis) in 1993 and 1995 which were slaughtered at urban markets in the Congo Republic. The samples were kept frozen and brought back to Onderstepoort for aerobic culture. Out of 29 specimens, 33 species of bacteria and 20 species of fungi were isolated. The bacteria included three isolates of Salmonella and eight isolates of Escherichia coli, most of the latter being rough strains. The flora of individual specimens contained 1-5 bacterial and 0-5 fungal species. Neither Aeromonas hydrophila nor Edwardsiella tarda were isolated from any of the samples.

Streptococcus phocae infections associated with starvation in Cape fur seals.

Mortalities and abortions associated with starvation occurred at Cape Cross, Namibia, in Cape fur seals (Arctocephalus pusillus pusillus). Affected seals showed lethargy and emaciation, and the most common pathological signs were those of a respiratory infection, both in adults and offspring. Streptococcus phocae was isolated from adult seals, a cub and aborted foetuses.

The clinical efficacy of enrofloxacin in the treatment of experimental bovine pneumonic pasteurellosis.

The clinical efficacy of enrofloxacin was tested in calves with experimentally induced pneumonic pasteurellosis. A strain of Pasteurella haemolytica, biotype A, serotype 1 (P. haemolytica A1), which had been isolated from an outbreak of pneumonic pasteurellosis in feedlot calves, was used to induce the disease in 24 eight-month-old calves. Each animal received, by intratracheal injection, 6 x 10(11) colony forming units of P. haemolytica A1 in a four-hour log phase culture. Twelve similar animals were kept as non-infected controls (Negative Control group). Treatment of the infected animals commenced 40 h after infection and was as follows: 12 animals each received 2.5 mg/kg enrofloxacin subcutaneously and 12 animals each received 5 ml sterile saline intramuscularly (Positive Control group). All treatments were given once daily for three consecutive days. Clinical examinations were performed on all animals once daily, starting prior to infection and continuing until 12 d post-infection. The parameters evaluated were rectal temperature, habitus (attitude), ocular mucous membrane congestion and abnormal sounds on lung auscultation. On day 14 post-infection, all animals were killed and their lung lesions (if any) estimated as the percentage involvement of each pair of lungs. The only statistically significant (P > or = 0.05) differences observed were between the Negative Control group and the Positive Control group. Noticeable differences were seen between the enrofloxacin-treated group and the Positive Control group, but they were not statistically significant (P > 0.05). The average lung lesion score (pneumonic lesions as a percentage of total lung volume) for the Positive Control group was 12.1% and that of the enrofloxacin-treated group, 8.4%. This difference was not statistically significant (P > 0.05).

Experimental exposure of pregnant mares to the asinine-94 strain of equine arteritis virus.

Clinical, virological and serological responses were evaluated in 10 pregnant mares after different challenge exposures to the asinine-94 strain of equine arteritis virus (EAV). The outcome of maternal infection on the progeny was also investigated. Mares were inoculated intranasally (n = 4), intramuscularly (n = 2), intravenously (n = 1), or contract-exposed (n = 3). All inoculated mares developed pyrexia, 5 showed mild clinical signs related to EAV infection and 2 remained asymptomatic. Viraemia was detected in all the inoculated animals and shedding of virus from the respiratory tract occurred in 6. Five mares were re-challenged intranasally 7 and 15 weeks after inoculation. Clinical signs of the disease in these mares were limited to mild conjunctivitis. After re-challenge, virus was recovered from buffy coat cultures of 2 mares 2-6 days after re-infection. EAV was not recovered from colostrum and milk samples during the 1st week post partum. All inoculated mares seroconverted to EAV 8-12 days post inoculation and also seroconverted after re-challenge. No clinical signs of EAV infection were observed in the 3 mares kept in close contact during the post-inoculation and re-challenge periods. Serum neutralising antibody to the virus was detected in 1 in-contact mare only, while a detectable concentration of specific IgG was found by ELISA in the colostrum of 1 of the other in-contact mares. Eight of the mares gave birth to clinically normal foals, although 1 was born prematurely. Shortly after birth, 7 foals developed fever and variable clinical signs; 5 foals became septicaemic and 3 of them died 2-5 days after birth, while the remaining 2 were euthanased at 1 month of age. EAV was not recovered from the placenta, from buffy coat fractions of blood collected from foals immediately after birth and 1-3 days later, or from a range of tissues taken from the 3 foals that died and 2 that were euthanased. Virus was not isolated from tissues collected from 1 mare and her foetus 3 weeks after this mare was re-challenged.

Sterilisation of surgical instruments with formaldehyde gas.

Haemostatic forceps contaminated with Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus and Aspergillus flavus were exposed to formaldehyde gas for up to 48 hours at different temperatures and relative humidities. After 24 hours at 22 to 24 degrees C and a relative humidity of 73 per cent they were sterilised reliably and completely.

Escherichia coli serotypes in pigs in South Africa.

This retrospective study was based on 674 cases of colibacillosis in pigs submitted to the diagnostic bacteriology laboratory of the Onderstepoort Veterinary Institute (OVI) over the 20-year period ranging from 1971-1991. During this time, 28,840 cases from various livestock species were received, of which 4162 (14.4%) were from pigs. The 674 porcine cases selected for this study were included if an E. coli infection had been suspected by the referring veterinarian, and typable E. coli strains were then isolated by this laboratory. Enteritis (45.5%) and septicaemia (46.9%) were the most common syndromes, with agalactiae (1.4%) and abortion (1.1 %) representing a far lower prevalence. Oedema-disease signs were described by the submitting veterinarian in only 12 cases. Samples were received from weaners and sucklers in relatively equal numbers until 1981, but subsequently samples from sucklers declined, while those from weaners remained high. There were 69 different somatic and capsulated (OK) antigen groups associated with E. coli infections in pigs. Escherichia coli O149 was the most common isolate (45.8%), while E. coli O141 was the next most common isolate (18.3%). This was followed by O9 (8.9%), O20 (5.2%) and O8 (3.1%). All other serotypes together accounted for less than 20% of the total number of cases, and were isolated fewer than 20 times each. The fimbrial attachment factor, F4 (K88) was found associated with 46.9% of isolates.

The distribution of Pasteurella haemolytica serotypes among cattle, sheep, and goats in South Africa and their association with diseases.

Over an 8-year period (September 1986 to March 1994), a total of 497 organ specimens from sheep and goats and 96 from cattle, were received for their isolation of Pasteurella haemolytica. They were collected in seven geographical areas in South Africa (as it existed before the April 1994 elections). These areas include the eastern Cape, Transvaal (new name: Gauteng), Nambia, Orange Free State (new name: Free State), Natal (new name: KwaZulu-Natal), western Cape and the northern Cape. This investigation does not represent the statistical incidence of the organism from each region, only the distribution of serotypes isolated from organ specimens submitted from diseased animals in these regions. Pasteurella haemolytica serotype 6 was the most prevalent type isolated from sheep and goats, but was followed closely by types 9 and 2. From cattle, P. haemolytica serotype 1 comprised 39% of the isolates. In sheep and goats, the majority of serotypes were associated with pneumonia, followed by gangrenous mastitis ("blue udder") and septicaemia. The situation in cattle was similar regarding the incidence of pneumonia followed by septicaemia. Up to 33% of the isolates from cattle and sheep specimens were non-typeable.

Artificial transmission of Bolo disease in woolled sheep and attempted characterisation of the causative unclassified Corynebacterium sp.

Bacterial isolates (n = 38) previously cultured from sheep with Bolo disease were compared bacteriologically with known Corynebacterium spp. and Actinomyces spp. The isolates did not conform to any previously described species but closely resembled C. pseudodiptheriticum and C. urealyticum. More comprehensive tests are needed to classify this Corynebacterium sp. Bacterial cultures of this unclassified Corynebacterium sp. were used artificially to induce Bolo disease in Dohne Merino sheep (n = 20). Ten sheep were kept at Middelburg in the Cape Midlands (Northern Cape) under arid conditions and another 10 at Queenstown in the Eastern Cape in a more humid climate. Two suspensions containing 2.8 x 10(5) Corynebacterium sp. (inoculum A) and 2.8 x 10(9) Corynebacterium sp. (inoculum B) respectively were used to infect each sheep on 9 different sites on the skin. One sheep died during the course of the experiment. Corynebacterium sp. established itself on 81 out of 171 inoculation sites of the remaining sheep and caused typical lesions of Bolo disease, clinically and pathologically. Bolo disease lesions developed slowly over 175 days at Middelburg and 287 days at Queenstown. Weather conditions were unfavourable to the development of fleece-rot and mycotic dermatitis. No difference was seen in lesion development between rams and ewes or between sheep with 5 months' wool growth and those which were shorn before inoculation. More lesions developed with the higher concentration of inoculum B (49 sites positive) as compared to inoculum A (32 sites positive).