Background: The project "Antibiotic resistance in bacteria of animal origin -II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period [2003][2004][2005], with the aim to establish a continuous monitoring of antimicrobial susceptibility among veterinary laboratories in European countries based on validated and harmonised methodologies. Available summary data of the susceptibility testing of the bacterial pathogens from the different laboratories were collected.

The Enter-net surveillance system received results of antimicrobial sensitivity tests for isolates from over 27 000 cases of human salmonellosis in 2000 in 10 European countries. Almost 40% of isolates were resistant to at least one antimicrobial, with 18% multiresistant. Resistance to ampicillin, streptomycin, sulphonamides and tetracyclines was common, with over 20% of isolates resistant to at least one of these antimicrobials. Clinical resistance to ciprofloxacin was rare, with only 0.5% of isolates exhibiting such resistance (MIC >1.0 mg/l). Resistance to nalidixic acid coupled with a decreased susceptibility to ciprofloxacin (MIC 0.25-1.0 mg/l) was more common, with 14% of isolates showing these properties. Resistance to third-generation cephalosporins was rare with only 0.6% of isolates resistant to cefotaxime. In all countries multiple resistance was most common in Salmonella enterica serotype Typhimurium, with 51% of isolates multiresistant in total. In England and Wales multiple resistance was also prevalent in S. Virchow and S. Hadar, whereas in other countries multiple resistance was common in serotypes such as S. Blockley.

Background: The project "Antibiotic resistance in bacteria of animal origin -II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003-05. The aim of this project was to establish a program for the continuous monitoring of antimicrobial susceptibility of pathogenic and indicator bacteria from food animals using validated and harmonised methodologies. In this report the first data on the occurrence of antimicrobial resistance among bacteria causing infections in pigs are reported.

A 5-year survey, from 2000 to 2004, of results of antimicrobial susceptibility testing for 11 antimicrobials for 134,310 isolates of nontyphoidal salmonellas from cases of human infection in 10 European countries has demonstrated an overall increase in the occurrence of resistance, from 57% to 66% over the period of study. In contrast, multiple resistance (to four or more antimicrobial drugs) has declined from 18% to 15%. The most significant increase in resistance has been to nalidixic acid (14% to 20%), particularly in Salmonella enterica serovar Enteritidis (10% to 26%), the most common serovar. For England and Wales this increase has for the most part been attributed to infections linked to contaminated eggs originating outside the United Kingdom. For Salmonella Typhimurium, the second most prevalent serovar, there has been an overall decline in the occurrence of resistance to ampicillin, chloramphenicol, and tetracyclines, attributed to a decline in the occurrence of multiresistant Salmonella Typhimurium DT 104. For Salmonella Virchow, a serotype with a predilection for invasive disease, there has been a substantive increase in resistance to most antimicrobials, attributed to the spread of drug-resistant strains associated with poultry. Because of the widespread importation of foods, it is important that controls to reduce the emergence and spread of drug-resistant strains of Salmonella are internationally implemented.

This study investigates the distribution of pulsed-field gel electrophoresis (PFGE) profiles within Salmonella enterica serotype Enteritidis phage type (PT) 4 and S. Typhimurium definitive phage type (DT) 104, from cases of human infection in nine European countries from 2000 to 2004. Isolates were subtyped using standardized methods and gel images submitted by each participating country to the coordinating centre (Health Protection Agency Centre for Infections, London, UK), where they were entered into a central database, developed within BioNumerics software, and designated using an agreed nomenclature. S. Enteritidis PT4 (n=3637) was differentiated into 38 different profiles. Simpson's index of diversity (D) of profiles ranged from 0·2 to 0·4. Profile SENTXB.0001 represented at least 80% of all profiles in each country. S. Typhimurium DT104 (n=1202) was differentiated into 28 different profile types. Simpson's D was at least 0·6 in all countries except in Austria and Italy. In both these countries over 74% of S. Typhimurium DT104 profiles were STYMXB.0013. Profile STYMXB.0061, was predominant in Denmark, Spain, Finland and England & Wales where it represented between 36% and 45% of profiles. Profile STYMXB.0001 represented nearly half of all profiles in Scotland and 23% in England & Wales. PFGE is proving useful for further discrimination within S. Enteritidis PT4 and S. Typhimurium DT104. Ascertainment of international outbreaks involving common serotypes and phage types may be increased by the timely pooling of PFGE profiles within a central database readily accessible to all participating countries.