Salmonella enterica serotypes and antibiotic susceptibility in New Zealand, 2002-2007

We analysed the serotypes and antibiotic susceptibility of 1560 human and 1505 non-human Salmonella isolated in New Zealand (NZ) between 2002 and 2007. The most common serotypes in humans were Salmonella enterica serovar Typhimurium, S. Enteritidis, S. Brandenburg and S. Infantis. Over the 6-year period human cases due to S. Agona and S. Enteritidis increased and cases due to S. Typhimurium decreased. The most common serotypes from non-human sources were S. Typhimurium, S. Brandenberg, S. Hindmarsh and S. Infantis, and there were no significant changes over time. More isolates were non-susceptible to streptomycin than to any other antibiotic. Almost all isolates were susceptible to ciprofloxacin and gentamicin. There were significant trends of increasing non-susceptibility to streptomycin and sulfonamides in isolates from human and non-human sources, while ampicillin, tetracycline and multidrug non-susceptibility also increased in human isolates. Despite these increases, rates of antibiotic non-susceptibility in Salmonella in NZ are still lower than in many international settings.