Evolution of a major bovine mastitic genotype (rpoB sequence type 10-2) of Staphylococcus aureus in cows

Abstract

Evolution of a major bovine mastitic genotype (rpoB sequence type 10-2) of Staphylococcus aureus in cows §Staphylococcus aureus is the major pathogen leading to bovine mastitis globally while livestock-associated methicillin resistant S. aureus (LA-MRSA) has become a potential threat to public health. MRSA from bovine mastitis is not common but a methicillin susceptible S. aureus (MSSA) genotype, rpoB sequence type (RST)10-2 (RST10-2), is prevalent in Korea. To date, many genomic sequences from S. aureus have been elucidated, but the complete genome sequences of RST10-2 MSSA from bovine mastitis has never been reported. In this study, we determined the complete genome sequence of two RST10-2 MSSA that differ from each other in staphylococcal protein A and molecular prophage types [PMB64-1 (t2489/ mPPT0) and PMB81-4 (t127/mPPT1-2-3)] and conducted a comparative genomics study. The genomic sequences of PMB64-1 and PMB81-4 were more homologous to the representative human RST10-2 strains (MSSA476, MW2 etc.) compared to other RSTs. Most of them shared five common pseudogenes, along with high amino acid identity of four variable virulence genes that were identified in this study. However, PMB64-1 and PMB81-4 acquired different strainspecific pseudogenes and mobile genetic elements than the human strains. The unique pseudogene profile and high identity of the virulence genes were verified in RST10-2 field strains from bovine mastitis. Thus, bovine mastitic RST10-2 MSSA may have an evolutionary relationship with the human RST10-2 community-associated (CA) MSSA and CA-MRSA strains but may have adapted to cows.

Genetic characterization of Staphylococcus aureus isolated from Norway rats in Boston, Massachusetts

“…These isolates predominately reflected distinct clusters of S. aureus within the rodent reservoir and lack the human virulence gene pvl, suggesting animal adaptation. However, some recovered rat isolates were similar to strains of potential concern for human health (USA400/ST1) (de Matos et al, 2016) as well as S. aureus strains identified in domesticated animal species (Brody et al, 2008;Ko et al, 2019) a All recovered isolates were mecA and pvl negative.…”

Rapid Screening and Comparison of Chimeric Lysins for Antibacterial Activity against Staphylococcus aureus Strains

“…The SH3 domain of lysostaphin binds to the stem peptide of peptidoglycan with relatively high affinity, and there are no reports on modification of the stem peptide in S. aureus [ 49 , 50 ]. The prevalence of less susceptible RST2-1 and RST4-1 genotypes in humans may be the result of the acquisition of resistance mechanisms to bacteriophage lysins, including ALS2 [ 6 , 13 ]. The function of SsaA-like protein is unclear, but it is shared by all S. aureus strains.…”

“…Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) have been successfully applied in molecular epidemiological studies, and a more cost-effective and clinically informative method, rpoB sequence typing (RSTing), has been established [ 11 ]. Recently, more extensive experimental and in silico RSTing that included S. aureus strains from Korean bovine mastitis and the GenBank database has demonstrated the apparent prevalence of RST4-1 and RST2-1 in humans worldwide in addition to the presence of RST10-2 and RST3-1 in Korean mastitis-suffering cows and diseased chickens, respectively [ 11 , 12 , 13 ].…”

Rapid Antibacterial Activity Assessment of Chimeric Lysins

“…Activity of E. coli-Expressed ALS2-dA-L25 against Bovine, Poultry, and Human Strains of S. aureus ALS2-dA-L25 was expressed in E. coli and purified using a Ni-NTA column. The antibacterial spectrum of ALS2-dA-L25 was tested via plate lysis and turbidity reduction tests with 20 previously reported S. aureus strains from bovine mastitis, chicken arthritis, and human infection (Table 1) [41][42][43].…”