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Increased incidence of protothecal mastitis has been recorded in several countries in the past ten years. The main goal of this article is to draw the attention of scientific and professional community to the emerging issue of mammary protothecosis. The article collates currently known facts about infection reservoirs, predisposing factors for the development of mastitis, clinical manifestations of the disease, and potential transmission routes within the herd as well as the measures for control and eradication. We would like to point out that identification of protothecal mastitis on a dairy farm is associated with a range of problems. Early detection of infected animals can be difficult because of predominantly subclinical course of early-stage infection, which easily spreads between cows via the milking system. Spontaneous recovery has not been recorded and infected cows typically develop chronic mastitis with granulomatous infiltration and progressive loss of functional parenchyma of the mammary gland. Substantial economic losses and health damages associated with mammary protothecosis strongly emphasise the need for developing effective prevention strategies aimed at control of the infection.

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The presence of Listeria monocytogenes was evaluated in a small-scale meat processing facility in Montenegro during 2011-2014. L. monocytogenes isolates from traditional meat products and environmental swabs were subjected to a) molecular characterization b) serotyping by both multiplex PCR and next generation sequencing (NGS) c) potential antimicrobial resistance (AMR) was assessed by extraction of specific genes from NGS data and d) screening for the presence of some disinfectant resistance markers. Overall, traditional meat products were contaminated, most likely from incoming raw materials, with 4 major specific STs of L. monocytogenes (ST515, ST8, ST21, ST121) representing 4 clonal complexes (CC1, CC8, CC21, CC121) identified during the four-year period. These strains belonged to serogroup IIa which predominated, followed by IVb (ST515, CC1). The strains from environmental swabs belonged, exclusively, to ST21 and were isolated from cutting board and floor swabs in 2011. Furthermore, we found Tn6188, a novel transposon conferring tolerance to BC, to be specific to sequence type ST121. In addition, antimicrobial resistance genes mprF and fosX were present in clonal complexes CC21 and CC121, while complexes CC8 and CC1 exclusively harbored the mprF antimicrobial resistance gene.Molecular characterization of Listeria monocytogenes isolates from a small-scale meat processor in Montenegro, 2011Montenegro, -2014

Some Staphylococcus aureus strains, identified as causative agents of mastitis in cattle, exhibit the ability of producing a viscous extracellular polysaccharide layer (slime), which is nowadays considered to be a virulence factor, as it promotes bacterial adhesion onto the mammary epithelial cells and protects bacteria from opsonization and phagocytosis. Some strains of this genus are believed to exist in the form of a biofilm in the udder tissue, which may partly explain frequent therapeutic failures and a chronic course of infection. In this study we investigated the ability of slime production and biofilm formation in 70 subclinical and clinical bovine mastitis isolates S. aureus. Slime production was determined from colony morphology of isolates in Congo red agar. The ability of biofilm formation was assessed in a quantitative assay using a microtiter-plate test involving crystal violet staining and for selected strains, scanning electron microscopy on stainless steel coupons was done. Eight S. aureus isolates (11.42%) formed black colonies of dry consistency, characteristic for slime-producing strains. According to the result of microtiter plate test, 9 isolates (12.86%) were categorized as strong biofilm producers, 21 (30%) as moderate, and 40 (57.14%) as weak biofilm producers. Scanning electron microscopy revealed differences between investigated isolates with respect to their ability to colonize stainless steel surfaces and to form a three-dimensional biofilm structure

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Bacteria of the genus Salmonella, some Escherichia coli strains as well as other species of the family Enterobacteriaceae, manifest the ability to express a specific phenotype, which is commonly termed as the "rdar" (red, dry and rough) morphotype. Both rdar and non-rdar phenotypes are commonly found in the nature; however, rdar is of essential importance for bacterial survival in the environment, outside of the host organisms. In that respect, it is comparable with the process of spore formation in Gram-positive bacteria. In laboratory conditions, rdar morphotype demonstrates growth of aforementioned organisms on agar containing diazo dye Congo Red, appearing as dark red (violet), rough and irregularly margined colonies. A coordinated expression of the number of genes mediated by major transcriptional regulators CsgD (curli subunit gene D) is the prerequisite for the formation of rdar morphotype colonies. The key point in this process is the activation of csgBAC operon transcription, which encodes the synthesis of curli fimbriae and activates the AgfD regulated gene (AdrA) involved in the cellulose biosynthesis. Curli fimbriae and cellulose are two basic structural components of the rdar morphotype. Curli fimbriae enable initial surface adhesion and intercellular aggregation of bacteria, whilst the cellulose (and other exopolysaccharides) promotes intercellular interactions. CsgD affects the overall cell physiology towards a "bacterial multicellular behavior" pattern, such as biofilm formation. The colony growth on Congo Red agar is a widely accepted laboratory method used for bacteria from the family Enterobacteriaceae and highly conserved between Salmonella. However, repeated laboratory subpassaging results in the substantial loss of rdar morphotype and the formation of smooth mutants, suggests the necessity for using wild isolates. In this article, the characteristics of rdar and non-rdar morphotypes of diverse Salmonella serotypes isolated from animal feed, as well as Escherichia coli isolates originating from cows milk with clinical mastitis, were presented. The research indicates substantial importance of the rdar phenotype for the persistence of Salmonella in the environment and its entering the food chain as well as the potential role of rdar phenotype of Escherichia coli in the pathogenesis of recurrent coli mastitis in dairy cows.