Characterisation of Australian isolates of Actinobacillus capsulatus, Actinobacillus equuli, Pasteurella caballi and Bisgaard Taxa 9 and 11

Objective The objective of this work was to perform a comprehensive phenotypic characterisation of 16 isolates of bacteria previously identified as Actinobacillus equuli.
Design The 16 isolates that had been obtained from Australian animals – 15 from horses and one from a rabbit – were compared with reference strains of A equuli, A capsulatus, Pasteurella caballi and Bisgaard Taxa 9 and 11.
Results The characterisation study demonstrated that only nine of the isolates were A equuli . The other isolates were identified as A capsulatus (the isolate from rabbit), P caballi (one isolate), Bisgaard Taxon 11 (two isolates) and Bisgaard Taxon 9 (one isolate). The final two isolates could not be assigned to any recognised species or taxa.
Conclusion This study has highlighted the importance of a complete characterisation of Actinobacillus -like organisms isolated from horses and rabbits. The study represents the first time that A capsulatus, P caballi and Bisgaard Taxa 9 and 11 have been recognised as being present in Australia.     

Porcine pleuropneumonia in Australian pigs due to Actinobacillus pleuropneumoniae serovar 5

Book reviewed in this article: Guide to the Dissection of Domestic Ruminants . RE Habel Biology and Medicine of Rabbits and Rodents . JE Harkness and JF Wagner     

Brucellosis — a reply

Extract

Madam:- I appreciate the opportunity to comment on Mr Wallace's letter concerning the possible risks of disastrous results consequent upon too early withdrawal of vaccination with Brucella abortus Strain 19. He is certainly not alone in expressing this concern.     

Characterisation and antimicrobial sensitivity of haemophili isolated from pigs

A total of 70 haemophili from Australia pigs was compared with a range of reference strains of porcine haemophili. Forty-eight of the isolates were identified as Actinobacillus pleuropneumoniae biovar 1 and the remaining 22 isolates as Haemophilus parasuis. Forty one of the A. pleuropneumoniae isolates were used in a study to determine to the minimal inhibitory concentration (MIC) of 12 antimicrobial agents, or combinations of agents. Penicillin, neomycin, trimethoprim, trimethoprim-sulphamethoxazole and tetracycline all showed low MIC values, indicating their potential for the treatment of porcine pleuropneumonia, although 2 isolates showed resistance to tetracycline. A wide range of MIC values was encountered with the sulphonamides.     

BOOK REVIEWS

Book reviewed in this article:
Guide to the Dissection of Domestic Ruminants . RE Habel
Biology and Medicine of Rabbits and Rodents . JE Harkness and JF Wagner     

Characterisation of a novel Mannheimia sp from Australian feedlot cattle

OBJECTIVE: To characterise eight isolates of a Gram-negative organism obtained from the upper respiratory tract of cattle showing evidence of mild upper respiratory tract disease. DESIGN: The isolates were compared with the five recognised species within the genus Mannheimia - M haemolytica, M glucosida, M granulomatis, M ruminalis and M varigena--using a range of phenotypic and genotypic methods. RESULTS: Phenotypic characterisation indicated that the isolates belonged to the trehalose-negative [Pasteurella] haemolytica complex. This complex has recently been reorganised into five species within the new genus Mannheimia. Ribotyping performed using HindIII and a computerised analysis system indicated that the eight Australian isolates formed a distinct cluster that was related to, but different from, the five recognised species of Mannheimia. The 16S rRNA sequence of one isolate (BNO311) was determined and a phylogenetic analysis performed. Isolate BNO311 was distinct from the five named Mannheimia spp but did join a larger cluster consisting of rRNA cluster IV (M varigena) and the unnamed rRNA cluster V of Mannheimia. DNA:DNA hybridisation between isolate BNO311 and M haemolytica NCTC 9380T, M granulomatis P411 and Actinobacillus ligniersii NCTC 4189T all suggested similarities of approximately 30%. CONCLUSIONS: These phenotypic and genotypic characterisation studies suggest that the eight Australian isolates represent a new species of Mannheimia. Until further characterisation studies are performed, we are unwilling to propose a name for this taxon, preferring to refer to this possible new species as Bisgaard taxon 39 of cluster V of Mannheimia.