Role of overcrowding in meticillin-resistant Staphylococcus aureus transmission: Bayesian network analysis for a single public hospital.

The transmission of multiple antibiotic-resistant organisms (MROs) in hospitals is affected by many inter-related factors. These include the background prevalence of the organism (burden), hand hygiene, the efficiency of patient screening, the isolation or cohorting of carriers, the quality of hospital cleaning, and bed occupancy. In addition, the prevalence of one MRO may influence the transmission of another by occupying isolation beds, and thus reducing isolation resources for the latter. For example, the overuse of third generation cephalosporin antibiotics can increase extended-spectrum ß-lactamase-producing Klebsiella pneumoniae, thus indirectly influencing the transmission of meticillin-resistant Staphylococcus aureus (MRSA). In order to study this complex system of interrelationships, we have employed a Bayesian network. We report results of the first two years of analysis for a single public hospital. We conclude that, within this institution, the association between high bed occupancy and increased transmission of MRSA may be subject to a dynamic multidimensional threshold and tipping point. This may be influenced by other factors such as MRSA burden and whether the high bed occupancy interferes with preparation and cleaning of beds for new patients and with hand hygiene and efforts to isolate or cohort carriers.

Radiizonates arcuatus, a distinctive new miospore species from the Lower Carboniferous of Western Gondwana.

A new species of trilete zonate miospores, Radiizonates arcuatus, is established for Lower Carboniferous Western Gondwanan forms hitherto ascribed misguidedly to Radiizonates genuinus (Jushko) Loboziak and Alpern (1978), a Russian Lower Carboniferous species. The latter binomen is, moreover, not a valid combination and is more correctly designated as Vallatisporites genuinus (Jushko) Byvsheva, 1980. R. arcuatus is, from records to date, confined to westerly parts of Gondwana (Brazil, North Africa and Middle East), in which it is characteristic of Early Carboniferous strata, albeit with some slightly older and slightly younger occurrences.

Tick-borne diseases in Australia.

Tick bites are a common problem in Australia and an important cause of morbidity in medical and veterinary practice. Complications include local inflammation and infection, paralysis and transmission of various pathogens. Over the past three decades, several new tick-borne diseases have been recognised both in Australia and overseas. The importance of these diseases has also increased, in part due to greater recreational activities occurring in tick infested areas. However, our understanding of the microbiology and epidemiology of many of these diseases is incomplete.