Clostridium perfringens has been implicated in a broad array of enteric infections including the fatal haemorrhagic enteritis/enterotoxaemia syndrome in cattle. The beta2 toxin (CPB2), encoded by cpb2, is suspected to be implicated in this syndrome. However, among C. perfringens isolates from cattle suspected of clostridial disease, an atypical allele was recently found to predominate at the cpb2 locus and atypical corresponding CPB2 proteins were shown to be poorly expressed, thus arguing against a biologically significant role of the beta2 toxin in clostridial diseases in cattle. This study compared genotype and phenotype of the beta2 toxin between C. perfringens isolates from a group of healthy calves (n=14, 87 isolates) and from a group of enterotoxaemic calves (n=8, 41 isolates). PCR results revealed the exclusive presence of the typical \"consensus\"cpb2 in the enterotoxaemic group. Western blot analysis demonstrated that the typical variant of CPB2 was often expressed in isolates from enterotoxaemic calves (43.9%) and infrequently in isolates from healthy cattle (6.9%). These data suggest that the typical variant of the CPB2 toxin may play a role in the pathogenesis of cattle enterotoxaemia.

New WHO and Australian guidelines promote a risk-management approach for minimising exposure to pathogens in recreational waters. Between 2003 and 2005, they were applied to Lake Parramatta (10 ha, 450 ML), a potential recreation site in Sydney, Australia. A three stage approach was developed involving (1) initial suitability assessment using historic data, (2) revised suitability assessment based on new data and (3) characterisation of hazardous (especially wet weather) events. Contrary to the stage 1 suitability classification, stage 2 baseline data indicated that during dry weather the lake had water quality sufficient for primary contact recreation (95th percentiles for enterococci = 19 MPN/100, n = 50) and the major pathogen source was wildfowl. Guideline principles provided a rationale for collecting microbiological and geographic data needed to understand local cycles of lake contamination/recovery. The concept of hazardous events was particularly useful. Studies of stormwater events led us to identify a transition point (> 10 mm rainfall in 24 h) where human-faecal pathogen risks increased and access needed to be controlled. Together baseline and event data yielded operational tools (i.e. event detection methods, action triggers, auditing criteria, remediation priorities) for minimising bather exposure.

Enterotoxin production in Clostridium perfringens is both strain dependent and sporulation associated. Underlying these phenotypic observations must lie a genetic and molecular explanation and the principal keys will be held within the DNA sequence both upstream and downstream of the structural gene cpe. In accordance with the above we have sequenced 4.1 kbp of DNA upstream of cpe in the type strain NCTC 8239. A region of DNA extending up to 1.5 kb 5\' to cpe is conserved in all enterotoxin-positive strains. This region contains a putative ORF with substantial homology to an ORF in the Salmonella typhimurium IS200 insertion element and, in addition, contains multiple perfect consensus DNA-binding sequences for the Bacillus subtilis transition state regulator Hpr. The detailed structural elements revealed by the sequence analysis are presented and used to develop a new perspective on the molecular basis of enterotoxin production in this important food-poisoning bacterium.

Tests with 100 anaerobic bacterial isolates demonstrated comparability between ceftriaxone MICs obtained with the reference agar dilution procedure and those obtained with a broth microdilution susceptibility testing procedure. The aerobically incubated thioglycolate disk elution test was also evaluated. Six 30-micrograms ceftriaxone disks in 5 ml of thioglycolate separated strains for which MICs were less than or equal to 32 micrograms/ml from those for which MICs were greater than or equal to 64 micrograms/ml (6% overall discrepancies). Quality control limits for ceftriaxone agar dilution tests were determined to be as follows: Bacteroides fragilis ATCC 25285, 32 to 128 micrograms/ml; and Bacteroides thetaiotaomicron ATCC 29741, 64 to 256 micrograms/ml.