Natural outbreak of Streptococcus agalactiae (GBS) infection in wild giant Queensland grouper, Epinephelus lanceolatus (Bloch), and other wild fish in northern Queensland, Australia.

Ninety-three giant Queensland grouper, Epinephelus lanceolatus (Bloch), were found dead in Queensland, Australia, from 2007 to 2011. Most dead fish occurred in northern Queensland, with a peak of mortalities in Cairns in June 2008. In 2009, sick wild fish including giant sea catfish, Arius thalassinus (Rüppell), and javelin grunter, Pomadasys kaakan (Cuvier), also occurred in Cairns. In 2009 and 2010, two disease epizootics involving wild stingrays occurred at Sea World marine aquarium. Necropsy, histopathology, bacteriology and PCR determined that the cause of deaths of 12 giant Queensland grouper, three wild fish, six estuary rays, Dasyatis fluviorum (Ogilby), one mangrove whipray, Himantura granulata (Macleay), and one eastern shovelnose ray, Aptychotrema rostrata (Shaw), was Streptococcus agalactiae septicaemia. Biochemical testing of 34 S. agalactiae isolates from giant Queensland grouper, wild fish and stingrays showed all had identical biochemical profiles. The 16S rRNA gene sequences of isolates confirmed all isolates were S. agalactiae; genotyping of selected S. agalactiae isolates showed the isolates from giant Queensland grouper were serotype Ib, whereas isolates from wild fish and stingrays closely resembled serotype II. This is the first report of S. agalactiae from wild giant Queensland grouper and other wild tropical fish and stingray species in Queensland, Australia.

Genetic diversity among Mycoplasma species bovine group 7: clonal isolates from an outbreak of polyarthritis, mastitis, and abortion in dairy cattle.

A comprehensive genetic analysis of 60 Mycoplasma sp. bovine group 7 isolates from different geographic origins and epidemiological settings is presented. Twenty-four isolates were recovered from the joints of calves during sporadic episodes of polyarthritis in geographically distinct regions of Queensland and New South Wales, Australia, including two clones of the type strain PG5O. A further three Australian isolates were also recovered from the tympanic bulla, retropharyngeal lymph node and the lung and another three isolates had unconfirmed histories. Six isolates originated from Germany, Portugal, Nigeria, and France. Twenty-four epidemiologically related isolates of Mycoplasma sp. bovine group 7 were recovered from multiple tissue sites and body fluids of infected calves with polyarthritis, mastitic milk, and from the stomach contents, lung and liver from aborted foetuses in three large, centrally managed dairy herds in New South Wales, Australia. Restriction endonuclease analysis (REA) of genomic DNA differentiated 29 Cfol profiles among these 60 isolates and grouped all 24 epidemiologically related isolates in a defined pattern showing a clonal origin. Three isolates of this clonal cluster were recovered from mastitic milk and the synovial exudate of clinically-affected calves and appeared sporadically for periods up to 18 months after the initial outbreak of polyarthritis indicating a persistent, close association of the organism with cattle in these herds. The Cfol profile representative of the clonal cluster was distinguishable from profiles of isolates recovered from multiple, unrelated cases of polyarthritis in Queensland and New South Wales and from other countries. All 24 isolates from the clonal cluster possessed a plasmid (pBG7AU) with a molecular size of 1022 bp. DNA sequence analysis of pBG7AU identified two open reading frames sharing 81 and 99% DNA sequence similarity with hypothetical replication control proteins A and B respectively, previously described in plasmid pADB201 isolated from M. mycoides subspecies mycoides. Other isolates of bovine group 7, epidemiologically unrelated to the clonal cluster, including two clones of the type strain PG5O, possessed a similar-sized plasmid. These data confirm that Mycoplasma sp. bovine group 7 is capable of migrating to, and multiplying within, different tissue sites within a single animal and among different animals within a herd.

Salmonelliasis in wildlife from Queensland.

During a 20 yr period (1978 to 1998), 233 isolates of Salmonella spp. were cultured from 179 wildlife animals (representing 25 species), 32 crocodile (Crocodylus porosus) eggs and six crocodile nesting sites, and represented 59 different serotypes. Salmonella serotype Virchow, the major serotype infecting humans in north Queensland, (Australia) was common in macropodids, but was not found in reptiles and was isolated only once from cane toads (Bufo marinus). Investigations of human cases of salmonellosis should include simultaneous studies on wild and domestic animals in contact with the case.

Novel Propionibacterium infection in cattle.

OBJECTIVE: To describe four cases of infection in cattle, from geographically different places, with a presumptive new species of Propionibacterium, which causes granulomatous lesions in the head, thorax, abdomen, pelvic area and skin. PROCEDURE: Gross lesions, ranging from 0.5 to 15 cm and detected during routine carcase inspection at the abattoir, were submitted to the laboratory for routine testing in the National Granuloma Submission Program. The bacterium isolated was identified using morphological characteristics, biochemical reactions, cell wall components, products of fermentation and 16S rRNA gene sequencing. RESULTS: Gross lesions submitted for examination consisted of a fibrous outer capsule enclosing thick yellow pus-like material. A Gram-Glynn stain of the histological sections revealed colonies of Gram-positive, filamentous, branching bacteria. Bacteriological culture, cell wall analysis, biochemical reactions and 16S rRNA sequencing identified the organism as a Propionibacterium sp closely related to P cyclohexanicum and the P freudenreichii cluster. CONCLUSION: This is the first report of a Propionibacterium sp closely related to P cyclohexanicum and the P freudenreichii cluster associated with extensive granulomatous lesions in cattle in Queensland. Sequencing data are suggestive of a previously undescribed species of the Propionibacterium genus.

Evaluation of a competitive enzyme-linked immunosorbent assay to detect infection of cattle in sentinel herds in Queensland, Australia with bluetongue viruses.

A competitive enzyme-linked immunosorbent assay (ELISA) was used to detect serogroup specific antibodies to bluetongue viruses. This test is commercially available and was evaluated with serially collected sera from 10 sentinel herds of cattle maintained in Queensland, Australia during 1994. Determination of an infection during the period of observation was based on the development of a serum neutralisation (SN) test titre > or = 1:8 to any one of 8 bluetongue virus serotypes known to exist in Australia. Using the inhibition value of 40% recommended by the manufacturer to classify cattle as exposed to bluetongue viruses, the ELISA was highly sensitive (100%; 95% confidence interval, 77.9-100%) and moderately specific (86.4%; 95% CI, 77.0-93.0%), relative to the SN test. An inhibition value of 70% maximised both sensitivity (100%, lower 95% CI, 77.9%) and specificity (93.2%, 95% CI, 85.2-98.0%) of the ELISA. The chance (posttest probability) of an animal from which a serum sample had an inhibition value > or = 70 % in the ELISA developing an SN test titre > or = 1:8 was 93.6% (95% CI, 86.4-97.9%). Investigations of the temporal development of ELISA and SN test reactions, showed that the ELISA detected exposure to bluetongue viruses significantly (P = 0.0156) earlier than the SN test. The bluetongue virus ELISA is a useful test in surveillance programs. False positive assay results make it inappropriate for monitoring and diagnosis, unless it is used in conjunction with the SN test.

Microbiological evaluation of dressing procedures for crocodile carcases in Queensland.

Microbiological testing of crocodiles during the dressing procedure has shown that sanitising the skin before skinning reduces the bacterial count on the skin and that dipping crocodile meat in 1.3% acetic acid solution effectively reduces bacterial levels. The total bacterial count on the processed mean sample was comparable with that obtained in the beef, pork and lamb industries. Salmonellae were isolated from 14 of the 72 carcases. Most (65%) of these isolates were in Salmonella subspecies III, formerly classified as Arizona.

Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei.

A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates.

Clinical and pathological observations on goats experimentally infected with Pseudomonas pseudomallei.

The effects in goats of the subcutaneous injection of varying doses of Pseudomonas pseudomallei (90 to 500,000 bacilli) suspended in normal saline are described. High doses (greater than or equal to 500 bacilli) caused acute, fatal infections. Lower doses (90 to 225 bacilli) caused acute or chronic disease when infection became established. However, 11 of 18 goats injected with the lower doses of bacilli showed no sign of infection on clinical or bacteriological examination. Response to antibiotic therapy with long acting tetracycline and chloramphenicol was minimal. Goats surviving the initial phase of infection tended to overcome the disease with a corresponding increase in the number of abscesses that were sterile at necropsy. In infected goats, clinical signs included undulating fever, wasting, anorexia, paresis of the hind legs, severe mastitis and abortion. At necropsy, abscesses were found predominantly in the spleen, lungs, subcutaneous injection site and its draining lymph node.

Isolation of Pseudomonas pseudomallei from clay layers at defined depths.

Twelve strains of Pseudomonas pseudomallei were isolated from the soil and water of a sheep paddock over a two-year period. The organism was recovered from the clay layer of the soil profile as well as from water that seeps into this layer during the "wet" season. Five isolates were obtained before the commencement of the "wet" season; environmental factors appear to play an important role in the survival of Ps. pseudomallei during the "dry" season. Lower isolation rates were recorded than those indicated by workers in southeast Asia and Iran.