title: Vancomycin-heteroresistant phenotype in invasive methicillin-resistant Staphylococcus aureus isolates belonging to spa type 041.
abstract: The aim of this study was to characterise invasive methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) strains from Italy and to investigate the presence of heteroresistant vancomycin-intermediate S. aureus (h-VISA). Eighty-two MSSA and 66 MRSA strains obtained from 19 laboratories were submitted to in vitro susceptibility testing; MRSA strains were also analysed by the macro Etest (MET) and vancomycin population analysis profiles (PAP) to detect the presence of h-VISA. Genotyping included the detection of agr locus, SCCmec typing, spa typing and multilocus sequence typing (MLST). By Etest, 66% of all isolates showed a minimum inhibitory concentration (MIC) >or=1.5 microg/ml and two MRSA strains were categorised as VISA (MIC = 3 microg/ml). Twelve MRSA strains were positive by MET; of these, 9 (14% of all MRSA) were confirmed as h-VISA by PAP. MRSA strains were assigned to 14 spa types, with t001, t008 and t041 including 77% of the isolates. The most common spa type, t041, characterised as ST228/273-MRSA-I (CC5) and comprising 24 isolates, included one VISA and eight h-VISA. This is the first description of a close association between h-VISA and t041, a spa type common in Italy and in other European countries, that highlights the importance of molecular typing to identify clones of special clinical relevance.
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Monaco
authors.forename: A
authors.initials: A
authors.lastname: Sanchini
authors.forename: H
authors.initials: H
authors.lastname: Grundmann
authors.forename: A
authors.initials: A
authors.lastname: Pantosti
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods; D016000:Cluster Analysis; D016172:DNA Fingerprinting / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics; D005838:Genotype; D006801:Humans; D007558:Italy / Q000453:epidemiology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D020713:Vancomycin Resistance
chemical_list: D004269:DNA, Bacterial
references.citation: J Clin Microbiol. 2003 Dec;41(12):5442-8
references.pmid: 14662923
references.citation: J Clin Microbiol. 2007 Feb;45(2):329-32
references.pmid: 17108069
references.citation: Microb Drug Resist. 2004 Spring;10(1):43-9
references.pmid: 15140393
references.citation: Diagn Microbiol Infect Dis. 2005 Jan;51(1):13-7
references.pmid: 15629224
references.citation: Antimicrob Agents Chemother. 2002 Jul;46(7):2155-61
references.pmid: 12069968
references.citation: Clin Microbiol Infect. 2005 Mar;11(3):214-20
references.pmid: 15715719
references.citation: J Infect Dis. 2009 Mar 1;199(5):605-9
references.pmid: 19199551
references.citation: Int J Antimicrob Agents. 2008 Nov;32(5):378-85
references.pmid: 18701261
references.citation: J Antimicrob Chemother. 2006 Jul;58(1):23-30
references.pmid: 16735433
references.citation: Ann Clin Microbiol Antimicrob. 2009 Jun 24;8:22
references.pmid: 19552801
references.citation: Clin Infect Dis. 1999 Nov;29(5):1128-32
references.pmid: 10524952
references.citation: J Clin Microbiol. 2008 Oct;46(10):3454-8
references.pmid: 18667599
references.citation: J Clin Microbiol. 2000 Mar;38(3):1008-15
references.pmid: 10698988
references.citation: Future Microbiol. 2007 Jun;2(3):323-34
references.pmid: 17661706
references.citation: J Clin Microbiol. 2003 Apr;41(4):1687-93
references.pmid: 12682161
references.citation: PLoS Med. 2010 Jan 12;7(1):e1000215
references.pmid: 20084094
references.citation: Clin Microbiol Infect. 2008 Mar;14 Suppl 2:3-9
references.pmid: 18226084
references.citation: Antimicrob Agents Chemother. 2000 Jun;44(6):1549-55
references.pmid: 10817707
references.citation: Am J Infect Control. 1988 Jun;16(3):128-40
references.pmid: 2841893
references.citation: Clin Infect Dis. 2004 Jun 15;38(12):1700-5
references.pmid: 15227615
references.citation: Science. 2003 Nov 28;302(5650):1569-71
references.pmid: 14645850
references.citation: Antimicrob Agents Chemother. 2009 Nov;53(11):4580-7
references.pmid: 19506057
references.citation: Clin Infect Dis. 2004 Feb 15;38(4):521-8
references.pmid: 14765345
references.citation: Clin Infect Dis. 2004 Feb 1;38(3):448-51
references.pmid: 14727222
references.citation: Emerg Infect Dis. 2001 Mar-Apr;7(2):327-32
references.pmid: 11294734
references.citation: Eur Respir J. 2009 Nov;34(5):1190-6
references.pmid: 19880619
references.citation: J Clin Microbiol. 2006 Feb;44(2):619-21
references.pmid: 16455927
references.citation: Ann Clin Microbiol Antimicrob. 2008 Apr 30;7:11
references.pmid: 18447939
references.citation: J Clin Microbiol. 2008 Sep;46(9):2950-4
references.pmid: 18632899
references.citation: Antimicrob Agents Chemother. 2008 Dec;52(12):4510-3
references.pmid: 18838583
references.citation: J Clin Microbiol. 2000 Feb;38(2):866-9
references.pmid: 10655401
references.citation: Clin Infect Dis. 2005 Jun 1;40(11):1705-6
references.pmid: 15889380
references.citation: Lancet. 1997 Dec 6;350(9092):1670-3
references.pmid: 9400512
references.citation: J Clin Microbiol. 2005 Oct;43(10):5026-33
references.pmid: 16207957
references.citation: Appl Environ Microbiol. 2003 Jan;69(1):18-23
references.pmid: 12513972
references.citation: Int J Antimicrob Agents. 2008 Apr;31 Suppl 2:1-9
references.pmid: 18485997