Detection of tetracycline and other antimicrobial residues in milk from cows with clinical mastitis treated by combination therapy

Abstract

The purpose of this study was to determine tetracycline and other antimicrobial residues in milk from dairy cows treated for clinical mastitis. Data on cow health and drugs used were obtained from the farm veterinarians. A milk sample from each affected udder quarter of each cow was taken for bacterial identification before treatment. All 35 cows in the study were treated with an intramammary product containing tetracycline, neomycin, bacitracin, and prednisolone (tetracycline injector) and also simultaneously with other drugs via the intramammary or parenteral route. The withhold period of the 'tetracycline product' was eight milkings but, in all cases, longer withhold periods were prescribed due to off-label application of additional combinations of drugs. Milk samples from treated udder quarters, taken two milkings before and two after the prescribed withhold period, were analysed for antimicrobial residues. Additionally, milk samples were taken from untreated healthy udder quarters to check if any crossover of drugs had occurred. Three screening tests were used for antimicrobial detection. In 15 (42·9%) cows the milk samples from the treated infected quarters contained tetracycline residues above the maximum residue limit (MRL) after the prescribed withhold period and, in two cases (5·7%) the same was true for neomycin and cefquinome residues. Cephalexin above the MRL was detected in only one case (2·9%). Beta-lactams did not exceed the MRL after the prescribed withhold period. Antimicrobial residues were not detected in milk samples from untreated quarters. Cow condition including parity, decreased milk production and severity of mastitis significantly influenced the excretion of antimicrobials in milk (P ≤ 0·05). No significant differences were found between the tetracycline positive and tetracycline negative cows regarding the bacteria involved, combination antimicrobial therapy, or treatment interval and duration.

Antimicrobial Residues in Food from Animal Origin—A Review of the Literature Focusing on Products Collected in Stores and Markets Worldwide

“…For a clearer evaluation, all studies with salmon, other fish from aquaculture, and shrimp were combined as seafood in the evaluation, as can be seen in Figure 2 . Cattle [ 17 , 18 , 19 , 20 , 21 , 22 ], Eggs [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], Milk [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ], Pork [ 58 , 59 , 60 ], Poultry [ 58 , 59 , 60 , 61 , 62 , 63 , 64 ,…”

The public health issue of antibiotic residues in food and feed: Causes, consequences, and potential solutions

“…Compared with microbiological methods, immunological methods such as enzyme-linked immunosorbent assay, fluoroimmunoassay, and time-resolved fluoroimmunoassay are highly specific, highly sensitive, simple, and cost effective. In addition, rapid-detection immunochromatographic kits (on strips) have been developed (TwinSensor), allowing within one assay the simultaneous screening of penicillins and cephalosporins (TwinSensor KIT034); beta-lactam and tetracycline (TwinSensor KIT020); beta-lactam antibiotics tetracyclines, streptomycin, and chloramphenicol (4Sensor BSCT-KIT060); beta-lactam antibiotics, sulfonamides, tetracyclines, and (Fluoro) quinolones (4Sensor BSTQ-KIT072) [61][62][63][64].…”

Emerging Electrochemical Sensors for Real-Time Detection of Tetracyclines in Milk

“…Tetracyclines are broad-spectrum antibiotics that are active against a range of Grampositive and Gram-negative bacteria, as well as some intracellular bacteria, such as chlamydiae, mycoplasmas and rickettsiae, and protozoan parasites [48]. In particular, tetracyclines are used on cattle for the treatment of bovine respiratory diseases (BRD) and mastitis [49,50]. Tetracyclines can be sorted into three categories depending on the timeframe of their development.…”