Developing targeted antimicrobial treatment protocols for mastitis

Morgans, Lisa

doi:10.1136/vr.m4309

Cited by 1 publication

(2 citation statements)

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“…New phenotypic rapid testing kits, such as MastDecide (MastDecide, Quidee GmbH, Homberg, Germany), are aiming to reduce the future over-usage of antimicrobials in dairy cows with the greater aim to decrease antimicrobial resistance. Rapid detection of mastitis-causing pathogens is necessary for early detection and treatment [ 18 ], with rapid direct sample tube test systems such as MastDecide providing positive results in >14 h [ 19 ] in comparison to conventional agar growth of 24–48 h or longer to result. Current point-of-care (POC) testing is often culture-based and includes some form of a modified agar plate, petrifilm or tube-based system, such as MastDecide.…”

Section: Introductionmentioning

confidence: 99%

“…High-throughput laboratory devices have likewise been developed to provide greater flexibility in analysing the problem of AMR [ 27 , 28 ]. Where an automated process for microbiological techniques can improve sample time [ 18 ], the use of microfluidic technology to detect pathogens and measure AMR may offer a point-of-treatment technique. This might avoid mastitis bacteria identification in a laborious and time-consuming manner within laboratories [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

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Dilution Reduces Sample Matrix Effects for Rapid, Direct, and Miniaturised Phenotypic Antibiotic Susceptibility Tests for Bovine Mastitis

Long,

Needs,

Edwards

2023

Antibiotics

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The time-consuming nature of current methods for detecting antimicrobial resistance (AMR) to guide mastitis treatment and for surveillance, drives innovation towards faster, easier, and more portable technology. Rapid on-farm testing could guide antibiotic selection, reducing misuse that contributes to resistance. We identify challenges that arise when developing miniaturized antibiotic susceptibility tests (AST) for rapid on-farm use directly in milk. We experimentally studied three factors: sample matrix (specifically milk or spoiled milk); the commensal bacteria found in fresh bovine milk; and result time on the performance of miniaturised AST. Microfluidic “dip-and-test” devices made from microcapillary film (MCF) were able to monitor Gram-negative bacterial growth colourimetrically even in the presence of milk and yoghurt (used to simulate spoiled milk samples), as long as this sample matrix was diluted 1:5 or more in growth medium. Growth detection kinetics using resazurin was not changed by milk at final concentrations of 20% or lower, but a significant delay was seen with yoghurt above 10%. The minimum inhibitory concentration (MIC) for ciprofloxacin and gentamicin was increased in the presence of higher concentrations of milk and yoghurt. When diluted to 1% all observed MIC were within range, indicating dilution may be sufficient to avoid milk matrix interfering with microfluidic AST. We found a median commensal cell count of 6 × 105 CFU/mL across 40 healthy milk samples and tested if these bacteria could alter microfluidic AST. We found that false susceptibility may be observed at early endpoint times if testing some pathogen and commensal mixtures. However, such errors are only expected to occur when a susceptible commensal organism is present at higher cell density relative to the resistant pathogen, and this can be avoided by reading at later endpoints, leading to a trade-off between accuracy and time-to-result. We conclude that with further optimisation, and additional studies of Gram-positive organisms, it should be possible to obtain rapid results for microfluidic AST, but a trade-off is needed between time-to-result, sample dilution, and accuracy.

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Section: Introductionmentioning

confidence: 99%