Submitted to: Proceedings of the International Conference on Emerging Infectious Diseases
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2010
Publication Date: 7/11/2010
Citation: Kabera, C., Cray, P.J., Barzilay, E., Whichard, J., Karp, B., Tong, E., Haro, J.H., Zhao, S., Mcdermott, P. Antimicrobial Resistance in Non-Typhoidal Salmonella from Humans, Retail Meats and Food Animals: 2002-2007. Proceedings of the International Conference on Emerging Infectious Diseases. July 11-14, 2010, Atlanta, GA. Interpretive Summary:
Technical Abstract: Background. The National Antimicrobial Resistance Monitor System (NARMS) tracks antimicrobial susceptibility in enteric bacteria from humans, retail meats and food animals. We analyzed changes in ceftiofur resistance (TioR), nalidixic acid resistance (NalR) and multidrug resistance (MDR-AmpC, defined as resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, tetracycline, amoxicillin/clavulanate, and ceftiofur) in non-typhoidal Salmonella from 2002-2007. Methods. Susceptibility data were collected on 11,986 human clinical Salmonella strains, 15,001 food animal strains (chickens, n=8301; turkeys, n=1544; cattle, n= 3442; and swine, n= 1714); and 1,700 retail meat isolates (chicken breast (CB), n= 704; ground turkey (GT), n= 862; ground beef (GB), n= 73; and pork chops (PC), n=61) recovered from 24,577 meat samples. Antimicrobial minimal inhibitory concentrations were determined by broth microdilution. Results. Most Salmonella from retail meats were recovered from CB (n=704) and GT (n=862). GB (n=73) and PC (n=61) strains were excluded from the analysis due to their small numbers. In Salmonella from chickens and turkeys, TioR increased from 10.2% and 3.3% in 2002 to 15.4% and 11.1% in 2007, respectively. TioR was higher in cattle than in other food animals, ranging from 13.3% to 21.6% during the study period, following a 1997 baseline of 0%. TioR in human strains ranged from 2.9% to 4.5% compared with 0.2% in 1996. In CB isolates, TioR rose from 10% in 2002 to 25.3% in 2003, then decreased to 16.2% in 2007. NalR in Salmonella from humans rose from 1.6% in 2002 to 2.2% in 2007, with a peak of 2.4% in 2006. NalR declined in Salmonella from GT and turkeys from 8.1% and 5.3% in 2002 to 2.6% and 1.1% in 2007. MDR-AmpC decreased from 3.4% to 2.1% in human strains, but remained highest in cattle isolates (ranging from 11.9% to 17.6%). MDR-AmpC gradually increased in chicken and turkey isolates, from 0.9% and 1.6% in 2002 to 1.4% and 4.1% in 2007, respectively. The proportion of isolates susceptible to all tested agents remained stable at around 80% for humans, but decreased in chickens from 62.0% to 53.9% and in turkeys from 29.9% to 15.5%. Summary. Overall, MDR-AmpC in human salmonellae did not increase from 2002 and 2007, while NalR increased slightly in human isolates. TioR increased in poultry at slaughter and was common in cattle isolates, yet among poultry isolates, was lowest in turkey-derived strains where MDR was most common.