Complete Genome Sequence of Pasteurella multocida Sequence Type 394, Isolated from a Case of Bovine Respiratory Disease in Australia.

Here, we present the completely closed genome sequence of Pasteurella multocida 17BRD-035, a bovine respiratory disease (BRD) pathogen from Queensland, Australia, with genes that confer resistance to ß-lactams, tilmicosin, and tetracycline. It consists of a single 2,624,884-bp chromosome and an average GC content of 40.23% and belongs to the newly described Rural Industries Research and Development Corporation (RIRDC) sequence type 394.

The evolution and distribution of phage ST160 within Salmonella enterica serotype Typhimurium.

Salmonellosis is an internationally important disease of mammals and birds. Unique epidemics in New Zealand in the recent past include two Salmonella serovars: Salmonella enterica subsp. enterica serovar Typhimurium definitive type (DT) 160 (S. Typhimurium DT160) and S. Brandenburg. Although not a major threat internationally, in New Zealand S. Typhimurium DT160 has been the most common serovar isolated from humans, and continues to cause significant losses in wildlife. We have identified DNA differences between the first New Zealand isolate of S. Typhimurium DT160 and the genome-sequenced strain, S. Typhimurium LT2. All the differences could be accounted for in one cryptic phage ST64B, and one novel P22-like phage, ST160. The majority of the ST160 genome is almost identical to phage SE1 but has two regions not found in SE1 which are identical to the P22-like phage ST64T, suggesting that ST160 evolved from SE1 via two recombination events with ST64T. All of the New Zealand isolates of DT160 were identical indicating the clonal spread of this particular Salmonella. Some overseas isolates of S. Typhimurium DT160 differed from the New Zealand strain and contained SE1 phage rather than ST160. ST160 was also identified in New Zealand isolates of S. Typhimurium DT74 and S. Typhimurium RDNC-April06 and in S. Typhimurium DT160 isolates from the USA. The emergence of S. Typhimurium DT160 as a significant pathogen in New Zealand is postulated to have occurred due to the sensitivity of the Salmonella strains to the ST160 phage when S. Typhimurium DT160 first arrived.

A class 1 integron present in a human commensal has a hybrid transposition module compared to Tn402: evidence of interaction with mobile DNA from natural environments.

In a survey of class 1 integrons from human stools, an unusual class 1 integron from a strain of Enterobacter cloacae was isolated and characterized in detail. Sequence analysis of a fosmid containing the class 1 integron revealed a complex set of transposons which included two Tn402-like transposons. One of these transposons, Tn6007, included a class 1 integron with two non-antibiotic-resistance-type gene cassettes and a complete transposition module. This tni module is a hybrid with a boundary within the res site compared to Tn402, implying that a site-specific recombination event generated either Tn6007 or Tn402. The second Tn402-like transposon, Tn6008, possesses neither a mer operon nor an integron, and most of its tni module has been deleted. Tn6007, Tn6008, and the 2,478 bases between them, collectively designated Tn6006, have transposed into a Tn5036/Tn3926-like transposon as a single unit. Tn6006, Tn6007, and Tn6008 could all transpose as discrete entities. Database analysis also revealed that a version of Tn6008 was present in the genome of Xanthomonas campestris pv. vesicatoria. Overall, the E. cloacae isolate further demonstrated that functional class 1 integrons/transposons are probably common in bacterial communities and have the potential to add substantially to the problem of multidrug-resistant nosocomial infections.