A Livestock-Associated, Multidrug-Resistant, Methicillin-Resistant Staphylococcus aureus Clonal Complex 97 Lineage Spreading in Dairy Cattle and Pigs in Italy

Abstract

S taphylococcus aureus is a major pathogen causing considerable human morbidity and mortality worldwide, and it is a leading cause of infections of some economically important livestock species and, as a prominent bacterial cause of contagious bovine mastitis, a major economic burden for the dairy cattle industry (1). Methicillin-resistant S. aureus (MRSA) lineages are causes of health care-and community-associated infections, which are a major burden of disease on a global scale (2). In the last decade, MRSA sequence type 398 (ST398) has found an ecological niche in the pig, cattle, and poultry industries, although other MRSA lineages (e.g., ST1, ST5, ST9, ST97, ST130, and ST433) have been identified in farmed animals worldwide (3) All these lineages are currently termed "livestock-associated MRSA" (LA-MRSA).The MRSA clonal complex 97 (CC97) lineage has been reported as the second most prevalent MRSA lineage in the Italian pig industry, where spa types t1730 and t4795, both belonging to ST97, were estimated to have colonized 11% of finishing holdings (4). In Italy, in the last 5 years, the CC97 MRSA lineage has also been increasingly detected in cattle primary production, either from mastitis in dairy cattle or from bulk tank milk (5-7). Occasionally, CC97 MRSA isolates have been detected in cattle in Germany and Spain.CC97 is one of the major S. aureus clonal complexes in bovines (8), and recently, a livestock origin of the human pandemic CC97 MRSA strains has been demonstrated, resulting in two emergent human epidemic CC97 community-acquired/associated MRSA (CA-MRSA) clones (8).The aim of this study was to determine the genetic relatedness of MRSA and methicillin-susceptible S. aureus (MSSA) CC97 isolates from pigs and dairy cattle in Italy in the last few years (2008 to 2012) for epidemiological and risk assessment purposes.

Livestock-Associated Methicillin-Resistant Staphylococcus aureus (MRSA) in Purulent Subcutaneous Lesions of Farm Rabbits

“…MRSA has emerged as a worrisome strain causing a wide variety of illnesses around the world and, although MRSA is primary associated with nosocomial infections, it has been found causing infections in pets, livestock and wild animals [16]. Livestock-associated MRSA (LA-MRSA) often belongs to clonal complex (CC) 398; nevertheless, other MRSA lineages have been identified as associated with LA-MRSA, such as CC1, CC9, CC130, and CC97 [17]. Additionally, livestock have been identified as a reservoir of MRSA, with zoonotic importance [18].…”

Bacteriophage Therapy: An Alternative for the Treatment of Staphylococcus aureus Infections in Animals and Animal Models

“…CC97 was irst described as associated with bovine mastitis cases and now has also been found in humans and pigs. Of particular interest is the case of a multidrug-resistant LA-MRSA genotype from Italy that has been transmited to pigs as MSSA and spilled back after methicillin resistance acquisition [8]. Ovine-associated S. aureus isolates are represented by CC133.…”

“…Due to the raise of methicillin-resistant S. aureus (MRSA) strains, this feature was included as a phenotypic marker to identify S. aureus, and now they are described as MRSA or methicillin-sensitive S. aureus (MSSA). Molecular epidemiology approaches helped to the ST deduced from homology between pet and human strains by PFGE and by spa-typing [65]; f [7]; g [8]; h [66]; i [67]. Table 1.…”

Methicillin-Resistant Staphylococcus aureus (MRSA) in Food- Producing and Companion Animals and Food Products

“…While a majority of the MRSA collected from dairy catle belonged to ST398 [89], other ST types, such as ST1-t286-SCCmec IV, ST72-t324 [108], ST59-t437-V [91], ST10-t127-SCCmec IVa genotype [92], SCCmec types IVg [109], CC97, t4795, and t1730 [110], and a mecA variant (mecA LGA251 ) known as mecC, are also reported from MRSA CC130 and ST425 isolates [111]. The mecC type was also detected in Danish MRSA CC130 isolated from a cow and the genotypic characteristics, such as spa type (t843), MLVA (MT429) and PFGE proiles of bovine isolates were the same as the human isolates, implying transmission between humans and ruminants [112].…”