title: Evaluation of MLVA for epidemiological typing and outbreak detection of ESBL-producing Escherichia coli in Sweden.
abstract: To identify the spread of nosocomial infections and halt outbreak development caused by Escherichia coli that carry multiple antibiotic resistance factors, such as extended-spectrum beta-lactamases (ESBLs) and carbapenemases, is becoming demanding challenges due to the rapid global increase and constant and increasing influx of these bacteria from the community to the hospital setting. Our aim was to assess a reliable and rapid typing protocol for ESBL-E. coli, with the primary focus to screen for possible clonal relatedness between isolates. All clinical ESBL-E. coli isolates, collected from hospitals (n = 63) and the community (n = 41), within a single geographical region over a 6 months period, were included, as well as clinical isolates from a polyclonal outbreak (ST131, n = 9, and ST1444, n = 3). The sporadic cases represented 36 STs, of which eight STs dominated i.e. ST131 (n = 33 isolates), ST648 (n = 10), ST38 (n = 9), ST12 and 69 (each n = 4), ST 167, 405 and 372 (each n = 3). The efficacy of multiple-locus variable number tandem repeat analysis (MLVA) was evaluated using three, seven or ten loci, in comparison with that of pulsed-field gel electrophoresis (PFGE) and multi locus sequence typing (MLST).
  
  
  
  MLVA detected 39, 55 and 60 distinct types, respectively, using three (GECM-3), seven (GECM-7) or ten (GECM-10) loci. For GECM-7 and -10, 26 STs included one type and eleven STs each included several types, the corresponding numbers for GECM-3 were 29 and 8. The highest numbers were seen for ST131 (7,7 and 8 types, respectively), ST38 (5,5,8) and ST648 (4,5,5). Good concordance was observed with PFGE and GECM-7 and -10, despite fewer types being identified with MLVA; 78 as compared to 55 and 60 types. The lower discriminatory power of MLVA was primarily seen within the O25b-ST131 lineage (n = 34) and its H30-Rx subclone (n = 21). Epidemiologically unrelated O25b-ST131 isolates were clustered with O25b-ST131 outbreak isolates by MLVA, whereas the ST1444 outbreak isolates were accurately distinguished from unrelated isolates.
  
  
  
  MLVA, even when using only three loci, represents an easy initial typing tool for epidemiological screening of ESBL-E. coli. For the ST131-O25b linage, complementary methods may be needed to obtain sufficient resolution.
authors.affiliation: Department of Infectious Diseases, Institution of Biomedicine, Sahlgrenska Academy and Centre for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Gothenburg, Sweden. lisa.helldal@vgregion.se.|Clinical Microbiology/Section for Bacteriology, Sahlgrenska University Hospital, Guldhedsgatan 10A, 413 46, Gothenburg, Sweden. lisa.helldal@vgregion.se.
authors.forename: Lisa
authors.initials: L
authors.lastname: Helldal
authors.affiliation: Department of Infectious Diseases, Institution of Biomedicine, Sahlgrenska Academy and Centre for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Nahid
authors.initials: N
authors.lastname: Karami
authors.affiliation: Department of Infectious Diseases, Institution of Biomedicine, Sahlgrenska Academy and Centre for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Welinder-Olsson
authors.affiliation: Department of Infectious Diseases, Institution of Biomedicine, Sahlgrenska Academy and Centre for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Edward R B
authors.initials: ER
authors.lastname: Moore
authors.affiliation: Department of Infectious Diseases, Institution of Biomedicine, Sahlgrenska Academy and Centre for Antibiotic Resistance Research (CARe) at the University of Gothenburg, Gothenburg, Sweden.|Swedish strategic programme against antibiotic resistance, Region Västra Götaland, Gothenburg, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Åhren
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D003428:Cross Infection / Q000382:microbiology; D004269:DNA, Bacterial; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D005798:Genes, Bacterial / Q000235:genetics; D056426:Genetic Loci / Q000235:genetics; D005838:Genotype; D006761:Hospitals; D006801:Humans; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D058889:Molecular Typing / Q000379:methods; D058885:Multilocus Sequence Typing / Q000379:methods; D012111:Residence Characteristics; D013548:Sweden / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase
keywords: ESBL; Epidemiological typing; Escherichia coli; H30-Rx ST131; MLVA; O25b-ST131