J Vet Sci.  2024 Jan;25(1):e6. 10.4142/jvs.23245.

Intramammary preparation of enrofloxacin hydrochloride-dihydrate for bovine mastitis (biofilm-forming Staphylococcus aureus)

• Córdova-González D
• Alfonseca-Silva E
• Gutiérrez L
• Tapia-Pérez G
• Sumano H

• KMID: 2553220
• DOI: http://doi.org/10.4142/jvs.23245

Abstract

Background
Chronic bovine mastitis is linked to biofilm-producing Staphylococcus aureus (bpSa) or Staphylococcus coagulase-negative (bp-Scn).
Objectives
Bp-Sa and bp-Scn were treated with intramammary preparations of either enrofloxacin HCl·2H₂O-dimethyl-sulfoxide-chitosan (enro-C/DMSO/chitosan) or enro-C alone. Their potential to inhibit and degrade biofilm formation in vitro was also assessed.
Methods
Milk samples were obtained from the affected quarters in a herd. Phenotypical and genotypical identifications as biofilm-producing Staphylococcus species were carried out. Enro-C/DMSO/chitosan and enro-C alone were assessed to determine their in vitro efficacy in interfering with biofilm formation and their bactericidal effects. A prolonged eight-day treatment with a twice-daily intramammary insertion of 10 mL of enro-C/DMSO/chitosan or enro-C alone was set to evaluate the clinical and bacteriological cures on day 10 in 15 cows per group and the biofilm-inhibiting ability.
Results
Fifty-seven percent of the isolates were identified as Staphylococcus spp., of which 50% were bp-Sa, 46% bp-Scn, and 4% Staphylococcus pseudintermedius. One hundred percent of the S. aureus isolated and 77% of Staphylococcus coagulase-negative were biofilm producers. In both groups, the icaA and icaD biofilm-producing genes were identified. The experimental preparation could inhibit biofilm formation, degrade mature biofilms, and have well-defined microbicidal effects on planktonic and biofilm bacteria. The respective clinical and bacteriological cure rates were 100% and 80% for enro-C/DMSO/chitosan and 41.7% and 25% for enro-C alone.
Conclusions
Enro-C/DMSO/chitosan eliminates bp-Sa and bp-Scn from cases of chronic bovine mastitis.

Keyword

Dairy cow; biofilm; chronic mastitis; Staphylococcus aureus; enrofloxacin