Efficacy of Targeted 5-day Combined Parenteral and Intramammary Treatment of Clinical Mastitis Caused by Penicillin-Susceptible or Penicillin-Resistant Staphylococcus aureus

Abstract

Procaine penicillin G (86 cases due to ß-lactamase negative strains) or amoxycillinclavulanic acid (24 cases due to ß-lactamase positive strains) was administered parenterally and intramammarily for 5 days. Efficacy of treatments was assessed 2 and 4 weeks later by physical examination, bacteriological culture, determination of CMT, somatic cell count and NAGase activity in milk. Quarters with growth of S. aureus in at least one post-treatment sample were classified as non-cured. As controls we used 41 clinical mastitis cases caused by penicillin-susceptible S. aureus isolates treated with procaine penicillin G parenterally for 5 days and 15 cases due to penicillin-resistant isolates treated with spiramycin parenterally for 5 days from the same practice area. Bacteriological cure rate after the combination treatment was 75.6% for quarters infected with penicillin-susceptible S. aureus isolates, and 29.2% for quarters infected with penicillin-resistant isolates. Cure rate for quarters treated only parenterally with procaine penicillin G was 56.1% and that for quarters treated with spiramycin 33.3%. The difference in cure rates between mastitis due to penicillin-susceptible and penicillinresistant S. aureus was highly significant. Combined treatment was superior over systemic treatment only in the ß-lactamase negative group. cow; mastitis; ß-lactamase.

Phenotypic and genotypic characterization of Staphylococcus aureus isolates in milk from flocks diagnosed with subclinical mastitis

“…Animals chronically infected are reservoires of penicillin resistant S. aureus and disseminate this phenotype. This dissemination associated with low rate of microbiological cure of mastitis caused by this microorganism allows animals chronically infected remain in the flock and spread resistant strains to other animals (Taponen et al, 2003;Barkema et al, 2006;Silva et al, 2012).…”

Genetic basis of penicillin resistance of S. aureus isolated in bovine mastitis

“…Penicillin-resistance may be linked to other virulence factors of S. aureus , which may facilitate the spread of resistant clones [33]. Intramammary infection remained significantly more often chronic if it was caused by bla Z positive (61.0% remained persistent) than blaZ negative (25.0%) strains [34]. In Denmark, penicillin resistance in mastitis causing S. aureus in 1950s was exclusively found in isolates of the same phagetype and ribotype, but found among several clones in 1992 [35].…”

Procaine penicillin alters swimming behaviour and physiological parameters of Daphnia magna

“…Procaine penicillin (PP) is a combination of a β-lactam antibiotic benzylpenicillin and procaine, a local anaesthetic used in human and veterinary medicine for treatment of certain bacterial infections mastitis, syphilis, anthrax, diphtheria and pneumococcal pneumonia (Crowe et al 1997 ; Wright 1999 ; Taponen et al 2003 ; Bazakis and Weir 2018 ). Although PP is one of the most commonly used antibiotics in the USA and Europe (Moulin et al 2008 ), a number of side effects in the central nervous system in both humans and animals including seizures and other abnormalities were described (Paine Jr 1978 ; Araskiewicz and Rybakowski 1994 ).…”