Virulence factors and ability of staphylococci from bovine milk and the cowshed environment to biofilm formation

Abstract

The aim of this study was to examine virulence factors and the ability of S. aureus and CNS species isolated from milk of cows with mastitis to form biofilm, and to compare them with virulence factors of staphylococci from milk of cows without mastitis and cowshed environment. Most of S. aureus strains from cows with mastitis showed haemolytic activity (93.9%), among them 72.7% and 21.2% produced α-and β-haemolysin, respectively. S. aureus from cows with mastitis symptoms produced proteases (above 48%) and esterase (42.4%). The highly significant relationship between the number of S. xylosus strains producing haemolysins (62%) and the origin of these strains from milk of cows with mastitis was observed. The ability to produce proteases was significantly associated with S. sciuri from milk of cows with mastitis. The ability of biofilm formation by staphylococcal strains from milk of cows with mastitis was greater than in strains from milk of cows without mastitis and the difference was significant (p≤0.05). The highest percentage of strains from milk of cows with mastitis were weak biofilm formers (48.6%), while 40% and 11.4% of strains were moderate and strong biofilm producers, respectively. S. xylosus showed the highest ability to form biofilm, while the lowest ability to form biofilm was observed in S. aureus and S. epidermidis.In conclusion, production of exotoxins and enzymes, and ability of biofilm formation shown by many CNS isolated from milk of cows with mastitis symptoms indicates that these features are important in pathogenesis of this disease.

Biofilm Formation Ability and Presence of Adhesion Genes among Coagulase-Negative and Coagulase-Positive Staphylococci Isolates from Raw Cow’s Milk

“…More importantly, a higher percentage of CoNS strains exhibited the capacity for forming a strong biofilm, compared to S. aureus strains. Similar observations were also demonstrated by other authors [ 29 , 35 ], which indicates the great potential for biofilm-forming by CoNS strains. The occurrence of microorganisms capable of biofilm formation suggests the need for the introduction of stricter control of milking hygiene, raw material storage and technological lines to prevent the spread of biofilm-forming staphylococcal strains which may result in disturbances in technological processes as well as the contamination of finished food products.…”

“…It is worth noting that the presence of potential pathogenic agents in certain strains of coagulase-negative staphylococci (the production of enterotoxins or biogenic amines) has a significant effect on food safety [ 27 ]. The obtained results of both this study and studies by other authors indicate a higher frequency of occurrence of CoNS than S. aureus isolates in raw milk [ 28 , 29 ].…”

“…All isolates subjected to testing were capable of biofilm formation in a strong, moderate or weak manner. The results of this study and studies by other authors [ 29 , 32 , 33 , 34 ] indicate a high percentage of staphylococci isolated from milk and the dairy production environment, which are capable of forming a biofilm. More importantly, a higher percentage of CoNS strains exhibited the capacity for forming a strong biofilm, compared to S. aureus strains.…”

Improved multiplex PCR primers for rapid identification of coagulase-negative staphylococci

“…Biofilm formation increases their antibiotic resistance by about 1000-fold over that of planktonic bacteria (Donlan 2002 ). In addition to biofilms, CNS species produce other diverse virulence factors and enzymes, such as hemolysin, lipase, lecithinase, DNase, and protease (Kot et al 2013 ). Alarmingly, a significant increase of multidrug-resistant CNS infections is observed (Koksal et al 2009 ).…”

Antibiotic Resistance and Detection of femA Gene in Staphylococcus Aureus Isolates from Raw Milk

“…S. aureus food poisoning is among the most prevalent types of poisoning in most countries (2,3). The variety of the bacteria habitats and imprudent and uncontrolled use of broad-spectrum antibiotics such as third generation cephalosporins, macrolides and fluoroquinolones are the contributing factors responsible for emergence of antibiotic (methicillin, vancomycin)-resistant S. aureus strains (4,5). FemA is a S. aureus-specific gene that encodes one of the several factors necessary for methicillin resistance.…”