Profiles of Staphyloccocus aureus isolated from goat persistent mastitis before and after treatment with enrofloxacin

Magna Coroa Lima,Thalita Moreira Scatamburlo,Richard Costa Polveiro,Sanely Lourenço Da Costa,Maria Aparecida Scatamburlo Moreira,Mateus Matiuzzi Da Costa,Mariana De Barros,Laís Karolyne De Castro,Samuel Henrique Sales Guimarães

doi:10.1186/s12866-020-01793-9

Magna Coroa Lima, Thalita Moreira Scatamburlo + Show 7 more

Open Access

https://doi.org/10.1186/s12866-020-01793-9

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Abstract

BackgroundStaphylococcus aureus is one of the main causative agents of mastitis in small ruminants. Antimicrobial use is the major treatment, but there are many flaws linked to resistance, tolerance or persistence. This study aimed to verify changes in resistance, virulence and clonal profiles of S. aureus isolated from persistent mastitis goat milk before and after enrofloxacin treatment.ResultsMIC increased to at least one antimicrobial in S. aureus isolates after enrofloxacin treatment compared to before. The most detected resistance genes before and after treatment were tetK, tetM, and blaZ, with more resistance genes detected after enrofloxacin treatment (p < 0.05). Occasional variations in efflux system gene detection were observed before and after treatment. Nine virulence genes (hla, fnbA, fnbB, eta, etb, sea, sec, seh, and sej) were detected at both times, and between these, the hla and eta genes were detected more in isolates after treatment. All isolates of S. aureus belonged to the same sequence type (ST) 133, except for two S. aureus isolates prior to enrofloxacin treatment which were classified as ST5 and the other as a new one, ST4966. Isolates of S. aureus 4, 8, and 100 from before and after treatment had identical pulse types, while others obtained from other animals before and after treatment were classified into distinct pulse types.ConclusionThere were occasional changes in the studied profiles of S. aureus isolated before and after treatment of animals with enrofloxacin, which may have contributed to the permanence of bacteria in the mammary gland, even when using traditional treatment, resulting in persistent mastitis.

Highlights

Staphylococcus aureus is one of the main causative agents of mastitis in small ruminants
The present study aims to verify changes in the clonal, resistance and virulence profiles of S. aureus isolated from the milk of goats with persistent mastitis, before and after treatment with enrofloxacin
Considering the same animal, a minimum inhibitory concentration (MIC) increase to at least one antimicrobial was observed for all S. aureus isolates after treatment, compared with the values found before it

Summary

Introduction

Staphylococcus aureus is one of the main causative agents of mastitis in small ruminants. Antimicrobial use is the major treatment, but there are many flaws linked to resistance, tolerance or persistence. This study aimed to verify changes in resistance, virulence and clonal profiles of S. aureus isolated from persistent mastitis goat milk before and after enrofloxacin treatment. Goat farms suffer severe economic losses due to staphylococcal intramammary infections, with Staphylococcus aureus being the main cause of clinical mastitis in small ruminants [1]. The use of enrofloxacin in goats and other small ruminants in mastitis treatments has been widely accepted by the main routes of administration and has proved its efficacy in the resolution of mastitis [3, 4]. The characterization of the genetic diversity of S. aureus is important to understand the pattern of dispersion of the pathogen [6]

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