Staphylococcus aureus (S. aureus) has been recognized as one of the important zoonotic pathogens. However, it was limited about the epidemiology and genetic characteristics of S. aureus isolated from pigs in Hunan province, china. The aim of this study was to determine the characteristics of 163 S. aureus isolated from 590 pigs in Hunan Province, China. All isolates were characterized by agr typing, detection of virulence genes and antibiotic resistance genes, lethal test of mice and antibiotic susceptibility tests. The results showed that 30 strains of the 163 isolates were divided into agrI (18.40%), agrII (36/163, 22.09%), agrIII (20/163, 12.27%,), agrIV (20/163,12.27%) and the remaining 57 isolates were amplified negative by agr primers. In the 163 isolates, the detection rate of the virulence genes hlb, hld, hla, icaA, seb, fnbA, eta, etb, sea, tst and pvl ranged from 2.45% to 100%. The 43 isolates that were lethal to the mice, had β-hemolytic activity, the number of virulence genes of which was 7.8% higher than that of the remaining 120 non-fatal strains. The resistance rates of the 163 isolates to the 15 antibiotics were 0% (0/163) - 100% (163/163). All isolates were susceptible to Vancomycin and only 7 isolates were methicillin - resistant S. aureus (MRSA). The detection rates of the 11 resistance genes was 0% (0/163) - 100% (163/163). This study first to describes the epidemiology and characteristics of S. aureus from pigs in Hunan Province, which will help in tracking the evolution of epidemic strains and preventing pig-human transmission events.

The Silurian fishes from north-western Hunan, China are characterised by the earliest known galeaspids

Dayongaspis Pan and Zeng, 1985 and Konoceraspis Pan, 1992, and the earliest known antiarch Shimenolepis

Wang J.-Q., 1991, as well as rich sinacanth fin spines. Shimenolepis from Lixian County in north-western

Hunan, which was dated as the Telychian (late Llandovery), has long been regarded as the oldest representative

of the placoderms in the world. As such, in addition to eastern Yunnan and the Lower Yangtze Region,

north-western Hunan represents another important area in South China that yields important fossil material

for the research of early vertebrates and related stratigraphy. Here we summarise the Silurian fishes known in

north-western Hunan so far, and classify them into three vertebrate assemblages (i.e., the Wentang, Maoshan,

and Yangtze assemblages). Based on the updated Silurian vertebrate and stratigraphic databases, the Silurian

fish-bearing strata in north-western Hunan can be subdivided into the Rongxi, Huixingshao, and Xiaoxi formations

in ascending chronological order, which can be correlated with the Lower Red Beds, the Upper Red Beds,

and the Ludlow Red Beds in South China, respectively. A new look at the Silurian strata in Lixian suggests that

the age of Shimenolepis is late Ludlow rather than late Llandovery as previously suggested. The research on

Silurian fishes and biostratigraphy in north-western Hunan not only provides morphological data of early vertebrates,

but also offers new palaeoichthyological evidence for the subdivision, correlation, and age assignment of

the Silurian marine red beds in South China. The establishment of a related high-precision Silurian stratigraphic

framework in north-western Hunan will help to elucidate the temporal and spatial distribution of Silurian fossil

fishes, deepen the understanding of the evolution of early vertebrates, and unravel the coevolution between

Silurian vertebrates and the palaeoenvironment.