Antibiotic resistance among Salmonella from human and other sources in New Zealand

Of 2210 salmonella isolates referred to the New Zealand Communicable Disease Centre for epidemiological surveillance during 1987, 147 (6.7%) were resistant to one or more of 10 antibiotics. Resistance to streptomycin was most common (4.5%), followed by sulphamethoxazole (3.4%), tetracycline (3.3%), ampicillin (1.5%), and kanamycin (1.4%). Resistance to cephalothin, chloramphenicol, gentamicin and trimethoprim occurred in less than 1% of isolates. There was no resistance to norfloxacin. Isolates from human sources were significantly (P less than 0.001) more resistant (10%) than those from other sources (3.2%). The majority of resistant isolates were resistant to more than one antibiotic, but multiresistance to five or more antibiotics occurred only among human isolates. Comparison of these results with data from earlier years shows that there has been little change in the incidence of resistance among salmonella in this country over the last 10 years. The prevalence of antibiotic resistance among salmonella in New Zealand is low relative to many other countries.