title: Molecular surveillance and population structure analysis of methicillin-susceptible and methicillin-resistant Staphylococcus aureus in high-risk wards.
abstract: In this study we report the results of analysis of 253 isolates of Staphylococcus aureus (132 methicillin [meticillin]-resistant S. aureus [MRSA] isolates and 121 methicillin-susceptible S. aureus [MSSA] isolates) from 209 patients admitted to 18 high-risk wards of six hospitals located in Florence, Italy, over an 8-month period during which a program of epidemiological surveillance of hospital-acquired infections was conducted. The majority (69%) of the 87 reported S. aureus infections were caused by MRSA. No outbreak events have been reported. All the isolates were typed by amplified fragment length polymorphism (AFLP), and AFLP profiles were analyzed in order to define similarity groups. The discriminatory power of AFLP is very high with MSSA (Simpson index of diversity [D], 95.9%), whereas its resolution capability with MRSA (D, 44.7%) is hampered by the well-known high clonality of these populations (the main MRSA group accounted for 74% of the MRSA isolates). Combining AFLP, improved by visual inspection of polymorphisms, with multiplex PCR greatly increases MRSA resolution (D, 85.5%), resolving the MRSA population to a level that is one of the highest reported in the literature. Widespread and sporadic clones of MSSA and MRSA were identified, and their diffusion in the different hospitals and wards over the surveillance period was studied. The understanding of MSSA and MRSA population structures should be the starting point for the design of a more rational surveillance program for S. aureus species, maximizing benefits and reducing the cost of infection control strategies.
authors: CIBIACI and Department of Evolutionary Biology, University of Florence, Florence, Italy.
authors: Simona
authors: S
authors: Sergi
authors: Francesca
authors: F
authors: Donnarumma
authors: Giorgio
authors: G
authors: Mastromei
authors: Emanuele
authors: E
authors: Goti
authors: Pierluigi
authors: P
authors: Nicoletti
authors: Patrizia
authors: P
authors: Pecile
authors: Daniela
authors: D
authors: Cecconi
authors: Roberta
authors: R
authors: Mannino
authors: Rosa
authors: R
authors: Fanci
authors: Alberto
authors: A
authors: Bosi
authors: Benedetta
authors: B
authors: Bartolozzi
authors: Enrico
authors: E
authors: Casalone
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054458:Amplified Fragment Length Polymorphism Analysis; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005838:Genotype; D006761:Hospitals; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007558:Italy / Q000453:epidemiology; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D008875:Middle Aged; D017720:Molecular Epidemiology; D011110:Polymorphism, Genetic; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial