Molecular prophage typing ofStaphylococcus aureusisolates from bovine mastitis

Abstract

Staphylococcus aureus is one of the major pathogens causing bovine mastitis and foodborne diseases associated with dairy products. To determine the genetic relationships between human and bovine or bovine isolates of S. aureus, various molecular methods have been used. Previously we developed an rpoB sequence typing (RSTing) method for molecular differentiation of S. aureus isolates and identification of RpoB-related antibiotic resistance. In this study, we performed spa typing and RSTing with 84 isolates from mastitic cows (22 farms, 72 cows, and 84 udders) and developed a molecular prophage typing (mPPTing) method for molecular epidemiological analysis of bovine mastitis. To compare the results, human isolates from patients (n = 14) and GenBank (n = 166) were used for real and in silico RSTing and mPPTing, respectively. Based on the results, RST10-2 and RST4-1 were the most common rpoB sequence types (RSTs) in cows and humans, respectively, and most isolates from cows and humans clearly differed. Antibiotic resistance-related RSTs were not detected in the cow isolates. A single dominant prophage type and gradual evolution through prophage acquisition were apparent in most of the tested farms. Thus, RSTing and mPPTing are informative, simple, and economic methods for molecular epidemiological analysis of S. aureus infections.

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

“…In a previous study, PMB64-1 and PMB81-4 showed different prophage types, mPPT0 and mPPT1-2-3, respectively; we verified the difference in the prophage profile (Ko et al, 2018). PMB64-1 was predicted to possess no prophage but PMB81-4 did show three intact prophages (ϕTEM123-like, ϕYMC/09/04/R1988-like, and ϕJS01-like prophages).…”

“…Recently, a high frequency of RST10-2 among bovine mastitis S. aureus strains in Korea was reported, and they were determined to be ST1 by MLST (Ko et al, 2018). Considering that the frequency of RST10-2 among human strains of which whole genome sequences were deposited in Gen-Bank was not high, a relatively high rate of Korean strains is present among RST10-2 (4/12, 33.3%), which is note-worthy (Table 6).…”

“…Eight S. aureus strains (PMB64-1, PMB81-4, PMB2, PMB46, PMB61, PMB132, PMB232, and PMB235) of RST10-2 and 11 strains of other RSTs [PMB196-1(RST2-1), PMB179-1 (RST4-1), PMB67-1 (RST5-2), PMB8-1 (RST8-1), PMB119-4 (RST10-3), PMB36-1 (RST11-4), PMB146-1 (RST11-5), PMB-236-1 (RST11-8), PMB177-1 (RST14-2), PMB65-1 (RST14-3), PMB4-1 (RST22-1)] from bovine mastitis in Korea were reported previously. All strains were cultivated on sheep blood agar (Hangang Co.) (Kim et al, 2017;Ko et al, 2018).…”

“…The genotypes of S. aureus from bovine mastitis are variable, but bovine multi-locus sequence type 1 (ST1) MRSA and MSSA strains in Italy share common genetic traits (Battisti et al, 2010;Monaco et al, 2013;Alba et al, 2015). To date, multiple genomic sequences of S. aureus from humans, domestic animals, and poultry are available in the GenBank database and the frequency of ST1 was the sixth highest among human strains following ST8, ST239, ST11, ST228, and ST72, in that order (Ko et al, 2018). Recently, we developed a molecular prophage typing (mPPTing) method for S. aureus and by combining it with RNA polymerase beta subunit gene (rpoB) sequence typing (RSTing), we classified bovine and human S. aureus strains (Seong et al, 2013;Ko et al, 2018).…”

Diversity and pathogenesis of Staphylococcus aureus from bovine mastitis: current understanding and future perspectives

“…The efb gene has also been reported to have a high prevalence in field isolates [123]. During human infection, the interaction of Efb with fibrinogen creates a protective shield with an anti-phagocytic role indicating an immunosuppressive role [53]. Although IsdA binds to fibrinogen and fibronectin [128], it has been well-studied as a vaccine target for mastitis control along with other iron-regulated proteins such as IsdB and IsdH due to their high immunogenicity, gene expression during IMI and presence of antibodies in milk of animals naturally infected with S. aureus [7,129,130].…”