title: Distribution of spa types among meticillin-resistant Staphylococcus aureus isolates during a 6 year period at a low-prevalence University Hospital.
abstract: This study describes the distribution and frequencies of strain types by protein A-encoding gene (spa) typing among a total of 200 meticillin-resistant Staphylococcus aureus (MRSA) single-patient isolates collected between 2000 and 2005 at the University Hospital Basel, Switzerland. Nine frequent spa types accounted for 49.5 % of MRSA isolates, whereas spa type t041 (15 % of all isolates) belonged to a local epidemic strain that is also a common strain type in southern Germany. Successful control of the outbreak strain was documented by epidemiological data and confirmed by spa typing results. The spa type t044 (3.5 %), corresponding to a widely disseminated European community-acquired MRSA (CA-MRSA), was first observed in 2002. The well-known CA-MRSA USA300 clone was detected in four patients (2 %). Sporadic strains occurring less than four times (32 different spa types) accounted for 23 % of isolates. No predominant spa type was seen, indicating a great genetic diversity. Only 34.5 % of patient isolates were acquired nosocomially. The presence of one or more of ten common virulence genes was shown in 79 % of strains. It was demonstrated that the sequence-based spa typing method allows analysis of local MRSA epidemiology in relation to other regions and countries over time.
authors.affiliation: Microbiology Laboratory, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Fenner
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Andreas F
authors.initials: AF
authors.lastname: Widmer
authors.affiliation: Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Marc
authors.initials: M
authors.lastname: Dangel
authors.affiliation: Microbiology Laboratory, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
authors.forename: Reno
authors.initials: R
authors.lastname: Frei
mesh_terms: D000328:Adult; D000368:Aged; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006785:Hospitals, University; D006801:Humans; D016106:Methicillin Resistance; D008875:Middle Aged; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013205:Staphylococcal Protein A / Q000235:genetics*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D013997:Time Factors; D014774:Virulence
chemical_list: D013205:Staphylococcal Protein A