title: Persistence of antimicrobial resistance in respiratory streptococci.
abstract: To assess whether persistence of antimicrobial resistance (i.e. non-susceptible resistance status) after treatment with penicillins or cephalosporins versus macrolides or tetracyclines differs and to compare the results obtained using routinely collected data with findings reported in prospective studies.
  
  
  
  Routinely collected microbiological data from 14 voluntary participating laboratories (2005) containing information on resistance status and individual antimicrobial consumption patterns (mid 2004-2005) were analysed using a generalised estimating equation (GEE) approach. The link function was adjusted to acknowledge that the proportion of resistant isolates in the population not treated with antibiotics [baseline resistance (BR)] is not necessarily zero. To optimise the comparability of this study with prospective studies, the analysis was repeated after removal of 14 isolates from patients who did not survive 2005.
  
  
  
  BR estimates were unstable and their confidence intervals were wide, which called for a sensitivity analysis using an adjusted GEE model with three different BR estimates. All models indicated that the proportion of susceptible isolates differed by treatment group and increased significantly over time, with this increase being independent of treatment group. Persistence of resistance after exposure to macrolides or tetracyclines was approximately three times as long as after exposure to penicillins or cephalosporins.
  
  
  
  Resistance following treatment with macrolides or tetracyclines persists longer than following treatment with penicillins or cephalosporins, which confirms the findings from prospective studies and suggests the use of routinely collected data as a valuable alternative to determine such differences in persistence of resistance.
authors.affiliation: Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), University of Hasselt, Agoralaan 1, Hasselt, Belgium; Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium. Electronic address: robin.bruyndonckx@uhasselt.be.
authors.forename: Robin
authors.initials: R
authors.lastname: Bruyndonckx
authors.affiliation: Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), University of Hasselt, Agoralaan 1, Hasselt, Belgium; Centre for Health Economic Research and Modelling Infectious Diseases (CHERMID), Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium.
authors.forename: Niel
authors.initials: N
authors.lastname: Hens
authors.affiliation: Interuniversity Institute for Biostatistics and Statistical Bioinformatics (I-BIOSTAT), University of Hasselt, Agoralaan 1, Hasselt, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Aerts
authors.affiliation: Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium.
authors.forename: Herman
authors.initials: H
authors.lastname: Goossens
authors.affiliation: Scientific Institute of Public Health (WIV-ISP), Juliette Wytsmanstraat 14, Brussels, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Latour
authors.affiliation: Scientific Institute of Public Health (WIV-ISP), Juliette Wytsmanstraat 14, Brussels, Belgium.
authors.forename: Boudewijn
authors.initials: B
authors.lastname: Catry
authors.affiliation: Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium; Centre for General Practice, Vaccine & Infectious Disease Institute (VAXINFECTIO), University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium.
authors.forename: Samuel
authors.initials: S
authors.lastname: Coenen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016022:Case-Control Studies; D002511:Cephalosporins / Q000494:pharmacology / Q000627:therapeutic use; D002648:Child; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D005260:Female; D006801:Humans; D016015:Logistic Models; D018942:Macrolides / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology / Q000627:therapeutic use; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D013290:Streptococcal Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D013291:Streptococcus / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity; D015996:Survival Rate; D013754:Tetracyclines / Q000494:pharmacology / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D018942:Macrolides; D010406:Penicillins; D013754:Tetracyclines
keywords: Antimicrobial resistance; Baseline resistance; Generalised estimating equation; Streptococcus pneumoniae; Streptococcus pyogenes