title: Linezolid-resistant staphylococcal bacteraemia: A multicentre case-case-control study in Italy.
abstract: The aim of this multicentre study was to analyse the characteristics of patients with bloodstream infections due to staphylococcal strains resistant to linezolid. This was a retrospective case-case-control study of patients hospitalised in three large teaching hospitals in Italy. A linezolid-resistant (LIN-R) Staphylococcus spp. group and a linezolid-susceptible (LIN-S) Staphylococcus spp. group were compared with control patients to determine the clinical features and factors associated with isolation of LIN-R strains. All LIN-R Staphylococcus spp. strains underwent molecular typing. Compared with the LIN-S group, central venous catheters were the main source of infection in the LIN-R group. The LIN-R and LIN-S groups showed a similar incidence of severe sepsis or septic shock, and both showed a higher incidence of these compared with the control group. Overall, patients in the LIN-R group had a higher 30-day mortality rate. Multivariate analysis found previous linezolid therapy, linezolid therapy >14 days, antibiotic therapy in the previous 30 days, antibiotic therapy >14 days, previous use of at least two antibiotics and hospitalisation in the previous 90 days as independent risk factors associated with isolation of a LIN-R strain. The G2576T mutation in domain V of 23S rRNA was the principal mechanism of resistance; only one strain of Staphylococcus epidermidis carried the cfr methylase gene (A2503), together with L4 insertion (71GGR72) and L3 substitution (H146Q). LIN-R strains are associated with severe impairment of clinical conditions and unfavourable patient outcomes. Reinforcement of infection control measures may have an important role in preventing these infections.
authors.affiliation: Department of Public Health and Infectious Diseases, Policlinico Umberto I, 'Sapienza' University of Rome, Viale dell'Università 37, 00161 Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Russo
authors.affiliation: University of Catania, Catania, Italy.
authors.forename: Floriana
authors.initials: F
authors.lastname: Campanile
authors.affiliation: Department of Public Health and Infectious Diseases, Policlinico Umberto I, 'Sapienza' University of Rome, Viale dell'Università 37, 00161 Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Falcone
authors.affiliation: UO Malattie Infettive, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Tascini
authors.affiliation: Infectious Diseases Clinic, Santa Maria Misericordia, University Hospital, Udine, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Bassetti
authors.affiliation: Department of Public Health and Infectious Diseases, Policlinico Umberto I, 'Sapienza' University of Rome, Viale dell'Università 37, 00161 Rome, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Goldoni
authors.affiliation: Department of Public Health and Infectious Diseases, Policlinico Umberto I, 'Sapienza' University of Rome, Viale dell'Università 37, 00161 Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Trancassini
authors.affiliation: Infectious Diseases Clinic, Santa Maria Misericordia, University Hospital, Udine, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Della Siega
authors.affiliation: UO Malattie Infettive, Azienda Ospedaliera Universitaria Pisana, Pisa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Menichetti
authors.affiliation: University of Catania, Catania, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Stefani
authors.affiliation: Department of Public Health and Infectious Diseases, Policlinico Umberto I, 'Sapienza' University of Rome, Viale dell'Università 37, 00161 Rome, Italy. Electronic address: mario.venditti@uniroma1.it.
authors.forename: Mario
authors.initials: M
authors.lastname: Venditti
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology*; D016022:Case-Control Studies; D055499:Catheter-Related Infections / Q000453:epidemiology / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D000069349:Linezolid; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing; D023303:Oxazolidinones / Q000494:pharmacology*; D017354:Point Mutation; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012189:Retrospective Studies; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013210:Staphylococcus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D000081:Acetamides; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D023303:Oxazolidinones; D012338:RNA, Ribosomal, 23S; D000069349:Linezolid
keywords: Bacteraemia; Central venous catheter; Linezolid; PFGE analysis; Staphylococcal infection