Efficacy of cefquinome and a combination of cloxacillin and ampicillin for treatment of dairy cows with Streptococcus agalactiae subclinical mastitis.

Rodolfo Santos Rossi,Simony Trevisan Guerra,Ariadne Ferreira Amarante,Vera Lucia Mores Rall,Jose Carlos De Figueiredo Pantoja,Giulia Soares Latosinski,Bruna Fernanda Rossi,Juan J Loor

doi:10.1371/journal.pone.0216091

Rodolfo Santos Rossi, Simony Trevisan Guerra + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0216091

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Journal: PloS one	Publication Date: Apr 25, 2019
Citations: 4	License type: CC BY 4.0

Affiliation: Universidade Estadual Paulista (Unesp)

Abstract

A randomized clinical trial was conducted to assess efficacy of intramammary cloxacillin and ampicillin (CLOXIMM), intramammary cefquinome (CEFIMM), and intramuscular cefquinome (CEFIM) to treat Streptococcus agalactiae intramammary infections (Trial 1). Subsequently, two treatment groups were extended to assess whether CLOXIMM was not inferior to CEFIMM (Trial 2). Nine farms were included in the study. Milk samples were collected from all quarters of all lactating cows for microbiological identification of S. agalactiae. Positive cows were randomly allocated into four groups: CLOXIMM, CEFIMM, CEFIM, or negative control (CONTROL). Study outcomes were bacteriological cure at 14 (CURE14), 21 (CURE21), and 14 and 21 (CURE1421) days after treatment onset, and somatic cell count. Logistic regression was used to estimate the odds of cure between each treatment and CONTROL. Non-inferiority analysis was performed considering a one-sided 95% confidence interval (CI) and non-inferiority margins (Δ) of 0.10, 0.15, 0.20, and 0.25. Adjusted S. agalactiae bacteriological cure for CLOXIMM, CEFIMM, CEFIM, and CONTROL was 86, 98, 55, and 25% at day 14; 82, 93, 52, and 0% at day 21; and 82, 92, 40, and 0% at days 14 and 21, respectively. Treatment with CLOXIMM and CEFIMM resulted in greater bacteriological cure rates, as compared with CEFIM or CONTROL, which does not justify the use of CEFIM in S. agalactiae eradication programs. The CURE14 difference between CEFIMM and CLOXIMM was of 12.1 percentage points (95% CI: 0.056–0.184). CLOXIMM was considered not inferior to CEFIMM for Δ = 0.20 or 0.25 and inconclusive for Δ = 0.10 or 0.15. Thus, it should be pondered by veterinarians whether an expected 12.1 (5.6–18.4) percentage points increase in cure rate would justify the use of a fourth-generation cephalosporin, as opposed to a combination of traditional IMM drugs (cloxacillin and ampicillin) to treat S. agalactiae subclinical mastitis.

Highlights

Control of contagious mastitis caused by Streptococcus agalactiae is still challenging in many dairy regions of the world
Results of this study demonstrated that both cefquinome and a combination of cloxacillin and ampicillin are effective to treat S. agalactiae Intramammary infections (IMI) when administered intramammarily
Results indicate that treatment with CLOXIMM or CEFIMM results in greater bacteriological cure rates, as compared with CEFIM or CONTROL

Summary

Introduction

Control of contagious mastitis caused by Streptococcus agalactiae is still challenging in many dairy regions of the world. In Brazil, herd and cow level prevalences have been reported as high as 60% [5], and 21% [6], respectively. Katholm et al [7] reported that herd prevalence of S. agalactiae increased from 2 to 6.1% in Denmark between 2000 and 2009. Intramammary infections (IMI) caused by S. agalactiae result in economic losses to farmers and dairy industries. Additional economic losses result from recurrent episodes of clinical mastitis experienced by chronically infected cows [1]. S. agalactiae IMI results in raw milk alterations, such as increased rate of lipolysis and proteolysis [12, 13], which negatively affect its industrial quality, yield, and shelf life

Results

Discussion

Conclusion