Comparison of the first whole genome sequence of 'Haemophilus quentini' with two new strains of 'Haemophilus quentini' and other species of Haemophilus.

Comparison of the genome of the Gram negative human pathogen Haemophilus quentini MP1 with other species of Haemophilus revealed that, although it is more closely related to Haemophilus haemolyticus than Haemophilus influenzae, the pathogen is in fact genetically distinct, a finding confirmed by phylogenetic analysis using the H. influenzae multilocus sequence typing genes. Further comparison with two other H. quentini strains recently identified in Canada revealed that these three genomes are more closely related than any other species of Haemophilus; however, there is still some sequence variation. There was no evidence of acquired antimicrobial resistance within the H. quentini MP1 genome nor any mutations within the DNA gyrase or topoisomerase IV genes known to confer resistance to fluoroquinolones, which has been previously identified in other H. quentini isolates. We hope by presenting the annotation and genetic comparison of the H. quentini MP1 genome it will aid the future molecular detection of this potentially emerging pathogen via the identification of unique genes that differentiate it from other species of Haemophilus.

Quantifiable downregulation of endogenous genes in Agaricus bisporus mediated by expression of RNA hairpins.

Functional gene studies in the cultivated white button mushroom Agaricus bisporus have been constrained by the absence of effective gene-silencing tools. Using two endogenous genes from A. bisporus, we have tested the utility of dsRNA hairpin constructs to mediate downregulation of specific genes. Hairpin constructs for genes encoding orotidine 5'- monophosphate decarboxylase (URA3) and carboxin resistance (CBX) were introduced into A. bisporus using Agrobacteriummediated transfection. Although predicted changes in phenotype were not observed in vitro, quantitative-PCR analyses indicated unambiguously that transcripts in several transformants were substantially reduced compared with the non-transformed controls. Interestingly, some hairpin transformants exhibited increased transcription of target genes. Our observations show that hairpin transgenic sequences can mediate downregulation of A. bisporus endogenous genes and that the technology has the potential to expedite functional genomics of the mushroom.

Implementation of compulsory hazard analysis critical control point system and its effect on concentrations of carcass and environmental surface bacterial indicators in United Kingdom red meat slaughterhouses.

Statutory microbiological test results were collected from British meat plants over a 4-year period from June 2002 to May 2006. A total of 49,074 carcass test results from 19,409 cattle, 14,706 sheep, and 14,959 pig swabs and 95,179 environmental test results from surface swabs were obtained. These test results were donated by 94 slaughterhouses, which process about two thirds of the British national annual throughput of cattle, sheep, and pig carcasses. The data were collectively analyzed to determine any historical trends for numbers of total aerobes and Enterobacteriaceae. Significant reductions were observed in the numbers of indicator organisms on carcasses for all three species between 2002 and 2006. Reductions were also observed for numbers of aerobes on environmental and food contact surfaces. There were seasonal differences in bacterial numbers isolated from carcasses. Cattle and sheep carcasses had significantly higher numbers of total aerobes and Enterobacteriaceae in late summer and early autumn, whereas numbers of total aerobes on pig carcasses were higher in winter. Bacterial numbers on environmental surfaces were not influenced by the month that the swab samples were collected. Possible reasons for the observed reductions in bacterial numbers on carcasses and surfaces and the implications for carcass testing for process control purposes are discussed.

Draft Whole-Genome Sequence of a Haemophilus quentini Strain Isolated from an Infant in the United Kingdom.

Haemophilus quentini is a rare and distinct genospecies of Haemophilus that has been suggested as a cause of neonatal bacteremia and urinary tract infections in men. We present the draft whole-genome sequence of H. quentini MP1 isolated from an infant in the United Kingdom, aiding future identification and detection of this pathogen.

Fate of pathogens present in livestock wastes spread onto fescue plots.

Fecal wastes from a variety of farmed livestock were inoculated with livestock isolates of Escherichia coli O157, Listeria monocytogenes, Salmonella, Campylobacter jejuni, and Cryptosporidium parvum oocysts at levels representative of the levels found in naturally contaminated wastes. The wastes were subsequently spread onto a grass pasture, and the decline of each of the zoonotic agents was monitored over time. There were no significant differences among the decimal reduction times for the bacterial pathogens. The mean bacterial decimal reduction time was 1.94 days. A range of times between 8 and 31 days for a 1-log reduction in C. parvum levels was obtained, demonstrating that the protozoans were significantly more hardy than the bacteria. Oocyst recovery was more efficient from wastes with lower dry matter contents. The levels of most of the zoonotic agents had declined to below detectable levels by 64 days. However, for some waste types, 128 days was required for the complete decline of L. monocytogenes levels. We were unable to find significant differences between the rates of pathogen decline in liquid (slurry) and solid (farmyard manure) wastes, although concerns have been raised that increased slurry generation as a consequence of more intensive farming practices could lead to increased survival of zoonotic agents in the environment.

Transfer of plasmid pBC16 between Bacillus thuringiensis strains in non-susceptible larvae.

Plasmid transfer was investigated in larvae of insects of the orders Coleoptera, Diptera, and Lepidoptera. The effects of introducing Bacillus thuringiensis strains in live non-susceptible larvae, and in the presence of added insecticidal toxins to kill the larvae, were examined. Plasmid transfer was not detected as the strains passed through non-susceptible live larvae, but was detected when the larvae were toxin-killed. The results indicate that growth of B. thuringiensis and plasmid transfer between strains while simply passing through an insect gut system is an infrequent event. In toxin-killed larvae, a more complex picture was recorded. B. thuringiensis subsp. kurstaki transferred pBC16 at a lower rate in killed Phaedon cochleriae larvae compared to previous work studying transfer with this strain in susceptible Lacanobia oleracea larvae. Similarly, B. thuringiensis subsp. tenebrionis transferred pBC16 in killed L. oleracea larvae, while no transfer in susceptible P. cochleriae larvae was detected. The results indicate that gene transfer was more frequent in killed L. oleracea larvae. When both B. thuringiensis strains were studied in Aedes aegypti, transfer of pBC16 was detected in toxin-killed larvae. This was surprising since in similar studies with strain B. thuringiensis subsp. israelensis that kills mosquitoes, transfer of pBC16 was not detected in mosquito cadavers. The improved transfer frequency of B. thuringiensis subsp. kurstaki and subsp. tenebrionis compared to B. thuringiensis subsp. israelensis in laboratory broth culture could account for this difference in detection of transfer within killed insects.