Problems associated with identification of Legionella species from the environment and isolation of six possible new species.

Following investigation of an outbreak of legionellosis in South Australia, numerous Legionella-like organisms were isolated from water samples. Because of the limited number of commercially available direct fluorescent-antibody reagents and the cross-reactions found with some reagents, non-pneumophila legionellae proved to be difficult to identify and these isolates were stored at -70 degrees C for later study. Latex agglutination reagents for Legionella pneumophila and Legionella anisa developed by the Institute of Medical and Veterinary Science, Adelaide, Australia, were found to be useful as rapid screening aids. Autofluorescence was useful for placing isolates into broad groups. Cellular fatty acid analysis, ubiquinone analysis, and DNA hybridization techniques were necessary to provide definitive identification. The species which were isolated most frequently were L. pneumophila, followed by L. anisa, Legionella jamestowniensis, Legionella quinlivanii, Legionella rubrilucens, Legionella spiritensis, and a single isolate each of Legionella erythra, Legionella jordanis, Legionella birminghamensis, and Legionella cincinnatiensis. In addition, 10 isolates were found by DNA hybridization studies to be unrelated to any of the 26 currently known species, representing what we believe to be 6 possible new species.

Outbreak of brucellosis at a South-Australian abattoir. 2. Epidemiological investigations.

The outbreak of human brucellosis among employees of a large South Australian abattoir described previously coincided with an increase in the number of cattle showing a positive serological reaction for Brucella abortus being slaughtered. Comparisons showed that two other abattoirs in the area were slaughtering larger numbers of such cattle, but no cases of human brucellosis were diagnosed there. This suggested an additional risk at the abattoir concerned. All infected men had been employed in a particular part of the works. There was a possibility of movement of aerosols, produced on opening the uteri of pregnant cattle, to other parts of the works, putting a larger number of workers at risk of infection. Modifications to the plant greatly reduced the spread of aerosols. No cases of human brucellosis were recorded at this abattoir during the summer of 1980-81.

Outbreak of brucellosis at a South-Australian abattoir. 1. Clinical and serological findings.

During the period October 1979 to May 1980, 22 cases of acute brucellosis occurred at a South Australian abattoir. We obtained blood samples for serological investigations and culture of Brucella abortus, and tested the sera using the standard agglutination test (SAT), dithiothreitol test (DTT), anti-human globulin test (AHG) and complement fixation test (CFT). Patients showed large variations in antibody levels in each of these tests, both on presentation and after treatment. Blood culture was successful in six of 15 patients in whom it was attempted. Using the experience gained during the outbreak, we defined a set of serological criteria for the diagnosis of acute brucellosis, particularly in those who are occupationally exposed.

Leptospiral titres in pigs after vaccination.

Two groups of 8 pigs were vaccinated and given a booster vaccination 6 weeks later each with a commercial dual L. pomona and L. tarassovi killed vaccine. Serum from bloods collected before and up to 30 weeks after vaccination had agglutinating antibodies only after the 0ooster vaccination and then only with 1 vaccine. Titres persisted less than 8 weeks when tested against L. pomona but up to 16 weeks when tested against L. tarassovi at the 1:300 dilution and up to 20 weeks at the 1:100 dilution.