title: A clonal outbreak of methicillin-susceptible Staphylococcus aureus with concomitant resistance to erythromycin, clindamycin and tobramycin in a Swedish county.
abstract: In contrast to methicillin-resistant Staphylococcus aureus (MRSA), studies on clonal distribution of methicillin-susceptible S. aureus (MSSA) are scarce. Since 2004, an increasing incidence of concomitant resistance to erythromycin, clindamycin and tobramycin (ECT) among MSSA has been detected in Ostergotland County, Sweden. The objectives of this study were to investigate the genetic relatedness among these isolates with 2 genotyping methods, pulsed-field gel electrophoresis (PFGE), and sequence-based typing of the polymorphic region X of the staphylococcal protein A gene (spa typing), and to determine the incidence of the Panton-Valentine leukocidin (PVL) gene. When genotyping 54 ECT-resistant MSSA isolates from 49 patients (1 isolate per patient per y), 91% were shown to be part of a clonal outbreak with both methods used (spa type t002). The clonal outbreak was concentrated in 8 hospital departments and 2 primary care centres, all located in the city of Linkoping. All isolates were negative for the PVL gene. In conclusion, this study demonstrates an ongoing clonal outbreak of PVL-negative ECT-resistant MSSA. This stresses the need to continuously maintain basic hygiene rules, since nosocomial transmission of pathogens is not limited to known resistant bacteria such as MRSA.
authors.affiliation: Department of Infection Control, Linkoping University Hospital, Linkoping, Sweden. maria.m.lindqvist@lio.se
authors.forename: Maria
authors.initials: M
authors.lastname: Lindqvist
authors.forename: Barbro
authors.initials: B
authors.lastname: Isaksson
authors.forename: Annika
authors.initials: A
authors.lastname: Samuelsson
authors.forename: Lennart E
authors.initials: LE
authors.lastname: Nilsson
authors.forename: Anita
authors.initials: A
authors.lastname: Hallgren
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000235:genetics; D002981:Clindamycin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004917:Erythromycin / Q000494:pharmacology; D005098:Exotoxins / Q000235:genetics; D005787:Gene Frequency; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D007956:Leukocidins / Q000235:genetics; D008712:Methicillin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013205:Staphylococcal Protein A / Q000235:genetics; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D013548:Sweden / Q000453:epidemiology; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D013205:Staphylococcal Protein A; D002981:Clindamycin; D004917:Erythromycin; D008712:Methicillin; D014031:Tobramycin