Characterization of Staphylococcus aureus from Humans and a Comparison with İsolates of Animal Origin, in North Dakota, United States.
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.
Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota, United States of America; Department of Animal Sciences, University of Concepción, Chillán, Chile.
Valeria
V
Velasco
Department of Microbiology, College of Veterinary Medicine, Uludag University, Bursa, Turkey.
Esra
E
Buyukcangaz
Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota, United States of America.
Julie S
JS
Sherwood
Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota, United States of America.
Ryan M
RM
Stepan
Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota, United States of America.
Ryan J
RJ
Koslofsky
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, United States of America.
Catherine M
CM
Logue
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D002417:Cattle; D002645:Chickens; D016000:Cluster Analysis; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005516:Food Microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests / Q000379:methods; D058885:Multilocus Sequence Typing / Q000379:methods*; D009296:Nasal Cavity / Q000382:microbiology; D009658:North Dakota; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012756:Sheep; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D055815:Young Adult
D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S