Network inference from population-level observation of epidemics.

Using the continuous-time susceptible-infected-susceptible (SIS) model on networks, we investigate the problem of inferring the class of the underlying network when epidemic data is only available at population-level (i.e., the number of infected individuals at a finite set of discrete times of a single realisation of the epidemic), the only information likely to be available in real world settings. To tackle this, epidemics on networks are approximated by a Birth-and-Death process which keeps track of the number of infected nodes at population level. The rates of this surrogate model encode both the structure of the underlying network and disease dynamics. We use extensive simulations over Regular, Erdos-Rényi and Barabási-Albert networks to build network class-specific priors for these rates. We then use Bayesian model selection to recover the most likely underlying network class, based only on a single realisation of the epidemic. We show that the proposed methodology yields good results on both synthetic and real-world networks.

Susceptibility of Enterobacteriaceae to beta-lactam agents and fluoroquinolones: a 3-year survey in France.

OBJECTIVE: To assess trends in the susceptibility to beta-lactam agents and to fluoroquinolones of clinically relevant Enterobacteriaceae isolated over a 3-year period in 14 French hospital laboratories. METHODS: During the second quarter of 1996, 1997 and 1998, 180 consecutive non-duplicate isolates of Enterobacteriaceae were collected in each center. Sixteen beta-lactams and four quinolones were tested by the disk diffusion method. In addition, the double-disk synergy test was used to screen for the production of extended-spectrum beta-lactamase (ESBL). RESULTS: Totals of 2507, 2312 and 2506 clinical isolates were obtained in each period, respectively. The distribution of Enterobacteriaceae species according to clinical specimens and wards was similar in each study period. No significant variation in the susceptibility rates to beta-lactams and fluoroquinolones was observed, except in Klebsiella pneumoniae and Enterobacter aerogenes. The prevalence of ESBL-producing isolates decreased from 18% to 9% in the former, while it increased from 32% to 54% in the latter. At the same time, the susceptibility to ofloxacin and pefloxacin increased for K. pneumoniae (P < 0.003) and cephalosporinase-producing species (P < 0.05), except Enterobacter spp. CONCLUSION: Over the 3-year study period beta-lactams and fluoroquinolones remained highly active against Enterobacteriaceae clinical isolates, with the exception of E. aerogenes, probably as a result of the dissemination of multiresistant clones in French hospitals.

[Repeated studies of the prevalence of Staphylococcus aureus in the nasal cavity in hemodialysed patients]. / Etude itérative de la prévalence du portage nasal de Staphylococcus aureus chez l'hémodialysé.

OBJECTIVES: In order to better establish a prevention strategy based on mupirocin, we evaluated nasal carriage of Staphylococcus aureus in haemodialysis patients over a 15 month period. METHODS: Search for Staphylococcus aureus in the nasal cavities was made every 2 months in 92 chronic dialysis patients. These patients were divided into 3 groups according to the nature of the carriage: non-permanent, intermittent or permanent. RESULTS: Among the 80 patients retained for analysis, there were 27.5% with intermittent carriage and 11.25% with permanent carriage. Factors which appeared to protect against carriage were rural residence and home self-dialysis. CONCLUSION: Repeated long-term search for nasal carriage of Staphylococcus aureus has provided reliable data for each patient and gave information on the effects of epidemiological conditions and health care structures.

[Fungal contamination of a dialysis water treatment system]. / Contamination par des champignons d'un circuit de traitement d'eau en autodialyse.

The authors report fungal contamination of the water delivery system in one of their dialysis centers. They emphasize the insufficiency of the legal recommendations for water analysis, as well as the economical and logistical consequences of this type of contamination. Finally, they suggest disinfection procedures allowing eradication of fungi.

[Hypersensitivity reactions during hemodialysis. Role of high permeability, retrofiltration and bacterial contamination of the dialysate]. / Réactions d'hypersensibilité en cours d'hémodialyse. Rôles de la haute perméabilité, de la rétrofiltration et de la contamination bactérienne du dialysat.

Since the more frequent use of highly permeable membranes and bicarbonate dialysate, hypersensitivity reactions are more often described during hemodialysis and raise the question of the entry of pyrogens from dialysate towards blood due to high permeability of membranes and to possible backfiltration. During dialysis sessions with such membranes, authors observed a severe collapse in a patient on bicarbonate fluid and a repeated Quincke's edema in another on acetate fluid. After exclusion of other causes of such hypersensitivity accidents, they discuss the role of bacterial contamination of dialysis fluid. They analyse the phenomenons of bidirectional high permeability and of backfiltration linked to these new membranes. They recall the different causes of dialysate contamination and give some means of avoiding these inconveniences which expose on one hand to acute severe reactions and on the other are prejudicial in the long term for the patients because of interleukin 1 production.

Anthrax meningitis. Report of two cases with autopsies.

The authors report two cases of occupation-related anthrax meningitis; one was direct contamination from a diseased animal; the second was due to handling of bone powder imported from India. The pathological pattern of involvement of the meninges and brain is described and discussed.

[Application of electroimmunodiffusion to the classification of streptococci. Study of 332 strains from hospital origin]. / Application de l'électro-immunodiffusion au groupage des streptocoques Etude de 332 souches d'origine hospitalière

Using a recent technic according to the principes of counter-immuno-electrophoresis, the authors corroborate the fact biochemical tests for streptococci are deficient. The work is practised in 332 samples from hospital.