Unraveling the microbiota of teat apices of clinically healthy lactating dairy cows, with special emphasis on coagulase-negative staphylococci

Abstract

Swab samples (n=72) obtained from the teat apex of lactating dairy cows without visual signs of inflammation (n=18) were gathered on 2 well-managed Flemish dairy herds (herds 1 and 2) during the same month to assess the bacterial diversity of teat apices before milking. A combination of both culture-dependent [plating and (GTG)(5)-PCR fingerprinting of the colonies] and culture-independent [denaturing gradient gel electrophoresis (PCR-DGGE)] techniques indicated that the teat apices contain a wide diversity of bacterial genera. Despite a low bacterial load, 20 bacterial genera of 3 phyla (Actinobacteria, Firmicutes, and Proteobacteria) were present. The most prevalent bacteria were the coagulase-negative staphylococci (CNS), encompassing a total of 15 species, which were identified to the species level using a combination of (GTG)(5)-PCR fingerprinting, gene sequencing (16S ribosomal RNA and rpoB genes), and a novel PCR-DGGE technique based on the tuf-PCR amplicon. Overall bacterial diversity did not differ significantly between the herds or between noninfected and subclinically infected quarters in herd 1. In herd 1, borderline significant lower CNS species diversity was found on teat apices of noninfected quarters compared with subclinically infected quarters. The most prevalent CNS species were Staphylococcus haemolyticus and Staphylococcus equorum in both herds and Staphylococcus carnosus in herd 2.

Short communication: Subtyping of Staphylococcus haemolyticus isolates from milk and corresponding teat apices to verify the potential teat-skin origin of intramammary infections in dairy cows

“…These inconsistencies could indicate strain dependence of the pathogenic versus protective potential of CNS. Although CNS are abundantly present on the teat apices and in the immediate environment of cows, differences exist between species in their adaptation to different niches (De Vliegher et al, 2003;Taponen et al, 2008;Piessens et al, 2011;Braem et al, 2013;De Visscher et al, 2014). Previously, S. chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus simulans, and Staphylococcus xylosus have been identified as the CNS species most likely to cause IMI (Piessens et al, 2011;Vanderhaeghen et al, 2014).…”

Technical note: A pilot study using a mouse mastitis model to study differences between bovine associated coagulase-negative staphylococci

“…The absence of coagulase production in transformed S. aureus remarkably diminished its intramammary virulence in mice (Jonsson et al, 1985); this most likely also relates to the minimal virulence of CNS in mice at first, as observed in the current study. The lower pathogenicity of the CNS strains compared with S. aureus explains the high prevalence of the former pathogens in the milk of clinically healthy cows and their less detrimental effects during bovine mastitis (Pate et al, 2012;Braem et al, 2013;Oikonomou et al, 2014).…”

Coagulase-Negative Staphylococci Favor Conversion of Arginine into Ornithine despite a Widespread Genetic Potential for Nitric Oxide Synthase Activity

“…In addition, the relevance of arginase for skin-associated CNS should be further investigated, as this may have important clinical implications. Some CNS are not only important opportunistic pathogens in humans; they may also affect mastitis in dairy herds (1,6,36). It has been suggested that the arginase activity of Helicobacter pylori (46) and Bacillus anthracis (47) plays an in vivo role in host-pathogen interactions, via inhibition of host nitric oxide production and T cell proliferation (48).…”

“…Hansen, Hør-sholm, Denmark) and S. carnosus 10P1-3 and S. xylosus 10P1-1 (Danisco, Copenhagen, Denmark) were isolated from commercial meat starter cultures (35). The authenticity of all strains was confirmed at the species level through rpoB gene sequencing (36). All strains were stored at Ϫ80°C in brain heart infusion (BHI) medium (Oxoid, Basingstoke, Hampshire, United Kingdom), supplemented with 25% (vol/vol) glycerol as a cryoprotectant.…”