MRSA - 'bug-bear' of a surgical practice: reducing the incidence of MRSA surgical site infections

Adverse publicity (the 'superbug') has demonstrated that the problem of MRSA (methicillin-resistant Staphylococcus aureus) is prevalent in many of the country's most prestigious hospitals. The results of the mandatory UK Department of Health (DH) surveillance for early surgical site infections in orthopaedic surgery (SSIS) have been published recently for the period April 2004 to March 2005 when 41,242 operations were studied ( 28 October 2005). Infection rates were generally and gratifyingly low but 48% of surgical site infections were caused by Staph. aureus and of those 68% were MRSA. The following article will discuss the aetiology and prevention of MRSA surgical site infection.     

Triple contrast ventriculography using air-lipiodol-dimer]

A mixture of three contrast media - air, Lipiodol and Dimer - was used in ventriculography in order to combine the advantages of each of them. Air is used for topographical localisation, Dimer shows the overall shape of the ventricular system and Lipiodol outlines blocks. This simple and rapid technique provides easily interpretable films, whatever the indication for the ventriculography.     

Techniques for continous measurement of local cerebral blood flow,PaO2,PaCO2 and blood pressure in the non-anesthetized animal

Summary Techniques have been developed for the study of cerebral blood flow (CBF) in non-anesthetized, non-curarized animals. Continuous recording of one or several local CBF in subcortical structures can be made, simultaneously with continous recordings of cerebral temperature,PaO₂,PaCO₂, arterial pressure and the E.Co.G. The CBF measurements, obtained by a thermal clearance method, are semi-quantitative.PaO₂ andPaCO₂ are measured quantitatively directly in the aorta by mass spectrography. Conventional techniques are used for the arterial pressure and the E.Co.G. recordings. The main advantage of the techniques described is the possibility of undertaking repeated long-duration recordings of the principal cerebro-vascular variables on animals not affected by operation stress or by drugs capable of modifying the regulation of CBF.     

Rapid and accurate identification of human isolates of Pasteurella and related species by sequencing the sodA gene

The identification of Pasteurella and related bacteria remains a challenge. Here, a 449- to 473-bp fragment (sodA(int)) internal to the sodA gene, encoding the manganese-dependent superoxide dismutase, was amplified and sequenced with a single pair of degenerate primers from the type strains of Pasteurella (18 strains), Gallibacterium (1 strain), and Mannheimia (5 strains) species. The sodA(int)-based phylogenetic tree was in general agreement with that inferred from the analysis of the corresponding 16S rRNA gene sequences, with members of the Pasteurella sensu stricto cluster (Pasteurella multocida, Pasteurella canis, Pasteurella dagmatis, and Pasteurella stomatis) forming a monophyletic group and Gallibacterium and Mannheimia being independent monophyletic genera. However, the sodA(int) sequences showed a markedly higher divergence than the corresponding 16S rRNA genes, confirming that sodA is a potent target to differentiate related species. Thirty-three independent human clinical isolates phenotypically assigned to 13 Pasteurella species by a reference laboratory were successfully identified by comparing their sodA(int) sequences to those of the type species. In the course of this work, we identified the first Gallibacterium anatis isolate ever reported from a human clinical specimen. The sodA(int) sequences of the clinical isolates displayed less than 2.5% divergence from those of the corresponding type strains, except for the Pasteurella pneumotropica isolates, which were closely related to each other (> 98% sodA(int) sequence identity) but shared only 92% sodA(int) identity with the type strain. The method described here provides a rapid and accurate tool for species identification of Pasteurella isolates when access to a sequencing facility is available.