Emergence of coagulase negative staphylococci in Southern Belgium - Facts and Figures | Emergences des staphylocoques coagulase négatifs en Wallonie - Etat des lieux

anglais. Since the early 1990s in Wallonia, coagulase negative staphylococci (CNS) have been identified as mastitis agent, both clinical and subclinical. As there epidemiological cluster has not yet been clearly classified between environmental and contagious pathogen, several questions subsists toward this class of mastitis etiological agents. From the late 1990s were the CNS represented 12% of infected quarters to 23% of all positive identifications in 2008, the CNS have taken a large part of the clinical cases of mastitis. Comparatively, CNS in Flanders represents only 7% of clinical cases identifications and 24% of subclinical cases. They still represent low inflammation pathogens, as for the average somatic cell count (SCC) of a CNS infection is 450.000 cells/ml (DETILLEUX, J. 1999. Preventive Veterinary Medicine, 41, 75-88.) but they represent for sure a source of treatment events in farm as for they provoke clinical mastitis. So, however they are seen as minor pathogens of a lesser matter regarding milk production drop, they still can imply a treatment a loss of discarded milk. Whether or not they should be treated could be approached through the Mammipack® project results. 124 common clinical mastitis events where sampled for bacteriology at day 0 and day 21 (Fig. 1). Farmer were asked to qualify the severity of the mastitis whether it had abnormal milk (score 1); abnormal quarter (score 2) or hyperthermia/anorexia (score 3). Also, they recorded the treatment used and we collected the SCC of each cow recorded, 2 months before the clinical signs until 3 months after. We decided to define as “chronic cases” cows showing SCC > 250.000 cells/ml the month before the clinical event and as “cured” cows showing SCC < 250.000 cells/ml the month after the event or the next one if the mastitis took place less than 15 days before test day. We could show that CNS infections still account for the least severe cases (Fig. 2), except for S. simulans, S. saprophyticus and S. hominis that shown some quarter indurations. While only 10% of clinical infection does remain clinically uncured to the farmer, figure 3 explains how 50% of CNS infections in our essay remained globally cured (Bacteriological and tissular), even if 40% of their treatments shown to be inadequate. Also, only one infection could be referred as a chronic case, all the others were acute cases. Though this study recorded a small amount of cases, yet we did not find any results differing from known characteristics of CNS infections. One interesting facts is the quite easy cure of the infected quarters given the poor quality of treatment.

Projet Mammipack 2009