Interleukin-6 as a Milk Marker of Clinical and Subclinical Intramammary Infections (IMI) in Cows Caused by Streptococcus spp.

The aim of the study was to evaluate the concentrations of Interleukin-6 (IL-6) in milk and serum of healthy cows (HE) and cows with mastitis caused by Streptococcus spp. The blood and milk samples were obtained from Holstein-Friesian cows (Lublin region, Poland). A total of 43 milk and serum samples from 28 cows with mastitis and 15 healthy cows were selected for study. IL-6 levels in milk from HE cows ranged from 6.09-80.24 pg/mL (median 26.6 pg/mL) and were significantly lower than in milk from both cows with clinical and subclinical mastitis (487.09 pg/mL vs. 26.6 pg/mL in CM, p < 0.001; and 165.31 pg/mL vs. 26.6 pg/mL in SCM, p < 0.001). The IL-6 concentration in the serum of HE was not significantly different from the serum IL-6 of the entire group of mastitis cows, regardless of whether the inflammation proceeded in a clinical or subclinical form (44.37 pg/mL vs. 78.09 pg/mL; 128.29 pg/mL vs. 78.09 pg/mL, respectively). The present study indicates that cows with mastitis caused by Streptococcus spp. develop a local immune response in the mammary gland in response to the pathogen. Monitoring of IL-6 levels in milk can allow early detection of mastitis, which is especially important in cases of subclinical inflammation.

Cytokine inflammatory response in dairy cows with mastitis caused by Streptococcus agalactiae.

Introduction: The aim of the study was evaluation of the concentrations of interleukin (IL)-1ß, IL-8, IL-12ß and tumour necrosis factor alpha (TNF-α) in the serum and milk of cows with mastitis caused by Streptococcus agalactiae. Material and Methods: A total of 60 milk samples from diseased cows and 30 milk samples from healthy cows were included in the study. Blood and milk samples were taken from Holstein-Friesian cows from three herds (two in tie-stall and one in a free-stall housing system) in Lublin Province in Poland. The concentrations of cytokines in blood serum and quarter milk samples were determined by ELISA. Results: The levels of IL-1ß, IL-8, IL-12ß and TNF-α were significantly higher in the milk of cows suffering from mastitis caused by S. agalactiae compared to the milk of healthy cows (263.03 vs 55.36 pg/mL, 298.34 vs 131.82 pg/mL, 604.10 vs 139.17 pg/mL and 460.86 vs 78.82 pg/mL, respectively). In the group of sick cows, cytokine levels were significantly higher in milk than in serum (263.03 vs 55.25 pg/mL for IL-1ß, 298.34 vs 164.22 pg/mL for IL-8, 604.10 vs 70.34 pg/mL for IL-12ß and 460.86 vs 104.78 pg/mL for TNF-α). Conclusion: The results confirm the involvement of the entire bovine immune system to protect against the bacteria first locally in the udder. The response of the mammary gland to infection caused by S. agalactiae is rapid and already very strong at the beginning of the infection.

Red foxes (Vulpes vulpes) as a specific and underappreciated reservoir of resistant and virulent coagulase-positive Staphylococcus spp. strains.

The aim of the study was to analyze the presence of coagulase-positive Staphylococcus in swabs collected from red foxes and to characterize the drug resistance and virulence of these bacteria. In total, 415 rectal and oral swabs were collected, and coagulase-positive strains of S. pseudintermedius (n = 104) and S. aureus (n = 27) were identified using multiplex-PCR and MALDI TOF MS. Subsequent analyses showed the highest phenotypic resistance of the strains to penicillin (16.8%) and tetracycline (30.5%) confirmed by the presence of the blaZ, tetM, and tetK genes. Slightly lower resistance to erythromycin (6.9%), clindamycin (9.2%), gentamicin, streptogramins, rifampicin, nitrofurantoin, and sulphamethoxazol/trimetophrim was exhibited by single strains. Several virulence genes in a few different combinations were detected in S. aureus; LukE-LukD, and seB were the most frequent genes (37%), LukE-LukD, seB, and seC were detected in 11% of the strains, and PVL, etA, etB, and tst genes were present in two or single strains. The results of our research have confirmed that the red fox is an underestimated reservoir of coagulase-positive Staphylococcus strains, with approximately 50% of carriers of at least one resistance gene. In turn, 88.8% of the S. aureus strains had one or more virulence genes; therefore, this species of wildlife animals should be monitored as part of epidemiological surveillance.