Characterization of Staphylococcus spp. strains in milk from buffaloes with mastitis in Brazil: the need to identify to species level to avoid misidentification

V Coimbra-E-Souza,R.C Chamon,M Giambiagi-Demarval,M.A.V.P Brito,M.S Laport

doi:10.1590/1678-4162-9351

Abstract

ABSTRACT Mastitis is an inflammation of the mammary gland that affects dairy cattle worldwide causing economic losses. Coagulase-negative staphylococci (CNS) are the predominant cause of this type of infection. We have recently showed that coagulase-positive staphylococci could be misidentified. So, the aim of this study was to characterize the Staphylococcus spp. strains initially classified as coagulase-negative Staphylococci, isolated from buffalo with subclinical mastitis. Milk of buffaloes with mastitis in herds was collected and 9 strains were identified as CNS by phenotypic tests. Molecular methodologies latter identified the strains as coagulase-negative Staphylococcus chromogenes (5), coagulase-positive Staphylococcus hyicus (2) and coagulase-positive Staphylococcus aureus (2). Our results strongly support the need to identify the isolates to a species level in order to avoid misidentification and to be aware of the classification using the coagulase test alone.

Highlights

Mastitis is an inflammation of the mammary gland that has a high impact on dairy cattle worldwide and causes considerable economic losses due to loss of milk quality and quantity, as well as the costs associated to treatment, veterinary services, culling and dairy cow replacement (Fabres-Klein et al, 2014)
Sequence homology found for the strains ranged between 98 and 100%. These nine isolates had been previously classified as coagulase-negative Staphylococcus spp. by the coagulase test
Coagulasenegative S. aureus variants have already been described and it has been alerted that incorrect diagnosis could result from bovine mastitis milk isolates (Akineden et al, 2011)

Summary

Introduction

Mastitis is an inflammation of the mammary gland that has a high impact on dairy cattle worldwide and causes considerable economic losses due to loss of milk quality and quantity, as well as the costs associated to treatment, veterinary services, culling and dairy cow replacement (Fabres-Klein et al, 2014). More recent studies have shown that CNS are emerging pathogens associated with the occurrence of mastitis and persistence of intramammary infection in dairy cattle (Fry et al, 2014). There has been an increasing interest in buffalo milk, both in research and as investment in various countries, mainly due to its beneficial nutritional content and for the production of cream, butter, yogurt, as well as many types of cheese (Michelizzi et al, 2010). There is a growing interest to produce high quality buffalo milk and to control diseases that might affect its production, such as mastitis

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