title: Changing Italian nosocomial-community trends and heteroresistance in Staphylococcus aureus from bacteremia and endocarditis.
abstract: Bloodstream infections due to Staphylococcus aureus (BSI) are serious infections both in hospitals and in the community, possibly leading to infective endocarditis (IE). The use of glycopeptides has been recently challenged by various forms of low-level resistance. This study evaluated the distribution of MSSA and MRSA isolates from BSI and IE in 4 Italian hospitals, their antibiotic susceptibility--focusing on the emergence of hVISA--and genotypic relationships. Our results demonstrate that the epidemiology of MRSA is changing versus different STs possessing features between community-acquired (CA)- and hospital-acquired (HA)-MRSA groups; furthermore, different MSSA isolated from BSI and IE were found, with the same backgrounds of the Italian CA-MRSA. The hVISA phenotype was very frequent (19.5%) and occurred more frequently in isolates from IE and in both the MSSA and MRSA strains. As expected, hVISA were detected in MRSA with vancomycin minimum inhibitory concentrations (MICs) of 1-2 mg/l, frequently associated with the major SCCmec I and II nosocomial clones; this phenotype was also detected in some MSSA strains. The few cases of MR-hVISA infections evaluated in our study demonstrated that 5 out of 9 patients (55%) receiving a glycopeptide, died. Future studies are required to validate these findings in terms of clinical impact.
authors.affiliation: Department of Bio-Medical Sciences, Section of Microbiology, University of Catania, Via Androne 81, 95124, Catania (I), Italy.
authors.forename: F
authors.initials: F
authors.lastname: Campanile
authors.forename: D
authors.initials: D
authors.lastname: Bongiorno
authors.forename: M
authors.initials: M
authors.lastname: Falcone
authors.forename: F
authors.initials: F
authors.lastname: Vailati
authors.forename: M B
authors.initials: MB
authors.lastname: Pasticci
authors.forename: M
authors.initials: M
authors.lastname: Perez
authors.forename: A
authors.initials: A
authors.lastname: Raglio
authors.forename: F
authors.initials: F
authors.lastname: Rumpianesi
authors.forename: C
authors.initials: C
authors.lastname: Scuderi
authors.forename: F
authors.initials: F
authors.lastname: Suter
authors.forename: M
authors.initials: M
authors.lastname: Venditti
authors.forename: C
authors.initials: C
authors.lastname: Venturelli
authors.forename: V
authors.initials: V
authors.lastname: Ravasio
authors.forename: M
authors.initials: M
authors.lastname: Codeluppi
authors.forename: S
authors.initials: S
authors.lastname: Stefani
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000382:microbiology*; D016000:Cluster Analysis; D003428:Cross Infection / Q000382:microbiology*; D004697:Endocarditis, Bacterial / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D007558:Italy; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents