Multidrug-Resistant Nontyphoidal Salmonellain New York State's Foodborne Diseases Active Surveillance Network Counties

AbstractWith the emergence of multidrug-resistant nontyphoidal (NT) Salmonella, knowledge of resistance patterns is critical for appropriate presumptive treatment. This report describes the prevalence and trends of NT Salmonellaantimicrobial susceptibility within the New York State (NYS) Foodborne Diseases Active Surveillance Network (FoodNet). The NYS Department of Health, Wadsworth Center Public Health Laboratory tested all Salmonellaisolates from the NYS FoodNet catchment area between May 2003 and December 2007 for antimicrobial susceptibility to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, tetracycline, nalidixic acid, and ciprofloxacin. Isolate susceptibility results were linked to their corresponding demographic and clinical data and analyzed. Multidrug-resistant isolates were defined as resistant to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline (R-type ACSSuT). Antimicrobial susceptibility for 2189 FoodNet cases (98.5% of total cases) showed 79.6% pansusceptible, 6.9% R-type ACSSuT, and 13.5% resistant to at least one antimicrobial agent but not R-type ACSSuT. Four (0.2%) isolates were resistant to ciprofloxacin. From 2004 to 2007, cases with R-type ACSSuT significantly decreased from 8.7% (37/424) to 4.8% (24/499) (p< 0.01). Serotypes with the highest proportion of R-type ACSSuT included SalmonellaTyphimurium 17.9% (79/444), and SalmonellaNewport 29.1% (51/175). Among SalmonellaTyphimurium isolates, over 40% of the African-American cases (19/46) had R-type ACSSuT isolates, compared with 15.7% of the Caucasian cases (58/369) (p< 0.01). R-type ACSSuT SalmonellaTyphimurium cases were hospitalized (41.8%) more frequently than pansusceptible SalmonellaTyphimurium cases (24.9%), after controlling for age (p< 0.05). Length of hospitalization was not significantly different. Although R-type ACSSuT NT Salmonellahas decreased since 2003 within the NYS FoodNet catchment area, monitoring resistance patterns remains important in identifying emerging resistant strains, vulnerable populations, and determining appropriate presumptive treatment regimens. The higher rate of R-type ACSSuT among the African-American cases requires further study.