Prevalence of Mycoplasma bovis udder infection in dairy cattle: preliminary field investigation in southeast France.

AIMS: To update epidemiological data on Mycoplasma bovis infection in dairy herds from six departments in the southeast of France, in order to obtain a first estimate of the prevalence of M. bovis infection through bacteriological investigations on bulk tank milk, and estimate the prevalence of M. bovis in clinical mastitis in this population of cattle. METHODS: To estimate a prevalence of M. bovis of 2%, with 95% confidence, a sample of >270 herds was required. Bulk tank milk samples were collected from herds between January and February 2005 and milk samples from cows with clinical mastitis were collected between January 2007 and March 2008. Bulk tank milk and composite mastitic samples were analysed for M. bovis using culture and/or PCR. RESULTS: Mycoplasma bovis was not detected by either technique in any of the 345 bulk tank milk samples. The prevalence of M. bovis infection in this population of dairy herds was <1%, with 95% confidence. Mycoplasma bovis was not isolated from any of the 166 composite samples obtained from 828 samples of mastitic milk. The prevalence of M. bovis in clinical mastitis was <0.44%, with 95% confidence. CONCLUSIONS: These preliminary results suggest that the prevalence of udder infections with M. bovis is very low in dairy herds in the southeast of France. These two studies provide preliminary data, that can be used to derive working hypotheses for future statistically representative investigations at the national level.

Identifying antimicrobial multiresistance patterns of Escherichia coli sampled from diarrhoeic calves by cluster analysis techniques: a way to guide research on multiresistance mechanisms.

Multiresistance is a critical issue. This study points out the usefulness of cluster analysis techniques to describe concisely the antimicrobial susceptibility patterns of bacterial isolates in a way that could effectively help in generating hypotheses on multiresistance mechanisms. Data were selected from the French antimicrobial resistance survey network on veterinary pathogens (Resapath). They were related to 1545 Escherichia coli isolates, which were isolated from faecal samples of diarrhoeic calves in France between 2002 and 2006. Ten clusters of isolates displaying similar features in terms of resistance profile to 13 relevant antimicrobials were computed. The presence of two to ten simultaneous resistances was detected in nine out of the ten clusters. Looking at potential mechanistic interpretations, results may suggest genetic links between some resistance mechanisms, but this should be confirmed by molecular investigation of the corresponding isolates. Looking at therapeutical potential implications, the high level of resistance and multiresistance to several antimicrobials observed in E. coli makes a critical reassessment of empiric oral antimicrobial therapy in calves highly desirable.

Quantitative evaluation of an experimental inflammation induced with Freund's complete adjuvant in dogs.

A chronic inflammation model in dogs was induced by intraarticular injection of Freund's Complete Adjuvant in the stifle. After a primary, acute response during the first 24 hr, a secondary subacute response was observed after a delay of approximately 3 weeks and persisted for several weeks. To evaluate the time course of the inflammatory process quantitatively, we tested more than 100 different parameters. Finally, only four parameters were selected based on practicability and metrological properties, namely, the body temperature, difference in skin temperature, difference in stifle diameter and vertical force exerted by arthritic hind limb measured using a force plate. The main results of the experimentation were the demonstration that these four parameters were sufficiently repeatable, reproducible, and appropriate to be used for quantitative evaluation of the inflammatory process, and that training of both animals and investigators was required. Finally, it was illustrated that an adjuvant periarthritis in dogs can be used to carry out a pharmacokinetic/pharmacodynamic modelling of an antiinflammatory drug.