Critical review on biofilm methods

Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research into the formation and elimination of biofilms is important for many disciplines. Several new methodologies have been recently developed for, or adapted to, biofilm studies that have contributed to deeper knowledge on biofilm physiology, structure and composition. In this review, traditional and cutting-edge methods to study biofilm biomass, viability, structure, composition and physiology are addressed. Moreover, as there is a lack of consensus among the diversity of techniques used to grow and study biofilms. This review intends to remedy this, by giving a critical perspective, highlighting the advantages and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms.The authors would like to acknowledge the support from the EU COST Action BacFoodNet FA1202

Epidemiology of intramammary infections with Staphylococcus aureus and mastitis streptococci in a dairy cattle herd with a history of recurrent clinical mastitis

The aim of the present work was to examine a dairy herd with an anamnesis of recurrent clinical mastitis and decreased milk production. A total of 239 individual cow milk samples originating from asymptomatic cows were collected at four-month intervals and examined mainly for the presence of Staphylococcus aureus and mastitis streptococci using standard cultivation methods. In total, 29.7% and 9.2% samples were positive for S. aureus and mastitis streptococci, respectively. Unlike for mastitis streptococci, the prevalence of animals positive for S. aureus had an increasing trend (p<0.05; Chi-squared test for trend) with rising parity. Despite in vitro susceptibility of S. aureus to potentiated penicillins and cephalosporins, the persistence of S. aureus was observed in cows undergoing intramammary treatment with amoxicillin/clavulanic acid (a potentiated penicillin antibiotic). All isolates of S. aureus were biofilm-positive and had the same macrorestriction pattern. Furthermore, no dependence was observed between the occurrence of S. aureus in milk and previous cases of clinical mastitis, reproductive and periparturient disorders and administration of antibiotics. In contrast to S. aureus, the occurrence of mastitis streptococci in milk was linked with previous cases of clinical mastitis and intramammary administration of antibiotics