Number of non-typhoidal Salmonella isolates that are resistant to gentamicin
Number of non- typhoidal Salmonella isolates tested for resistance to gentamicin
In 1996, surveillance for Salmonella in NARMS began in 14 sites. Since 2003, all 50 states have been participating, which represent a population of approximately 302 million (US census, 2007). Participating sites forward every twentieth non-typhoidal Salmonella isolate received at their public health laboratories to NARMS at CDC for susceptibility testing. Susceptibility testing involves the determination of the minimum inhibitory concentration (MIC) for 15 antimicrobial agents: amikacin, ampicillin, amoxicillin-clavulanic acid, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, ciprofloxacin, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. Resistance in non-typhoidal Salmonella is used for this objective. Non-typhoidal Salmonella excludes the following Salmonella serotypes: Typhi, Paratyphi A, Paratyphi B (i.e., tartrate negative isolates), and Paratyphi C. Tartrate positive Salmonella serotype Paratyphi B isolates are referred to as Salmonella serotype Paratyphi B var. L(+) tartrate+ and are not typically associated with typhoidal disease.