Characterization of Staphylococcus aureus from Humans and a Comparison with İsolates of Animal Origin, in North Dakota, United States

Abstract

Different clones of methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus have been found in humans as well as in animals and retail meat. However, more information about the genetic characteristics and similarities between strains is needed. The aim of this study was to identify and characterize Staphylococcus aureus from humans, and to compare their characteristics with isolates of animal origin. A total of 550 nasal swabs were taken from healthy humans, and S. aureus was isolated and identified. Positive S. aureus isolates were subjected to molecular typing and susceptibility testing. In addition, 108 MRSA isolates recovered from clinical patients in the state of North Dakota and 133 S. aureus isolates from animals and meat previously analyzed were included. The nasal carriage of S. aureus in healthy people was 7.6% and, in general, clones were genetically diverse. None of the S. aureus strains obtained from healthy people were mecA- or PVL-positive. A total of 105 (97.2%) MRSA isolates from clinical cases harbored the mecA gene and 11 (10.2%) isolated from blood stream infections harbored the PVL gene. The most common resistance profile among S. aureus from healthy people was penicillin, and from clinical cases were erythromycin-penicillin-ciprofloxacin. The rate of multidrug resistance (MDR) was 70% in humans. Most of the S. aureus harboring mecA and PVL genes were identified as ST5 and ST8, and exhibited MDR. However, S. aureus isolates of animal origin used for comparison exhibited a lower rate of MDR. The most common resistance profiles in isolates of animal origin were penicillin-tetracycline and penicillin-tetracycline-erythromycin, in animals and raw meat, respectively. The ST5 was also found in animals and meat, with ST9 and ST398 being the major clones. The genetic similarity between clones from humans and meat suggests the risk of spread of S. aureus in the food chain.

Antibiotic‐resistantStaphylococcus aureusstrains of swine origin: molecular typing and susceptibility to oregano (Origanum vulgareL.) essential oil and maqui (Aristotelia chilensis(Molina) Stuntz) extract

“…; Velasco et al . ) or borderline oxacillin‐resistant S. aureus (Nadarajah et al . ; Stefani et al .…”

“…Those strains were subjected to the detection of the mecC gene (Stegger et al 2012), a variation in the mecA gene, resulting also negatives for the mecC gene. This could be due to the presence of other variations in the mecA gene (Stegger et al 2012;Velasco et al 2015) or borderline oxacillin-resistant S. aureus (Nadarajah et al 2006;Stefani et al 2012).…”

“…In fact, the genetic similarity between clones from humans and meat suggests the risk of spread of S. aureus in the food supply chain (Velasco et al . ). In addition, MRSA and multidrug‐resistant (MDR) S. aureus strains have been detected in food‐producing animals, such as: pigs, cows and poultry; and food of animal origin, such as meat and milk (Buyukcangaz et al .…”

“…Therefore, there is a risk of transmission of S. aureus strains to humans and foodproducing animals (Pantosti 2012) with the consequent contamination of food. In fact, the genetic similarity between clones from humans and meat suggests the risk of spread of S. aureus in the food supply chain (Velasco et al 2015). In addition, MRSA and multidrug-resistant (MDR) S. aureus strains have been detected in food-producing animals, such as: pigs, cows and poultry; and food of animal origin, such as meat and milk (Buyukcangaz et al 2013;Friese et al 2013;Rajkhowa et al 2016;Khemiri et al 2018;Velasco et al 2018).…”

A US View on Antimicrobial Stewardship in Animal Agriculture

“…Genetically related strains of vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and multidrugresistant Klebsiella pneumoniae have been identified in healthy agricultural animals, colonized persons, and infected persons [8][9][10][11]. Occupational exposure to agricultural animals can increase the risk of acquiring an antibiotic-resistant organism [12][13][14][15].…”