|Headrick, Marcia - FDA-CVM|
|Tollefson, L - FDA-CVM|
Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2001
Publication Date: May 25, 2001
Citation: Gray,J.T.; Cray,P.J.; Headrick,M.L.; Tollefson,L. 2001. Expanded-spectrum cephalosporin resistance in salmonella isolates from animal origin and correlation with multi-drug resistance. American Society for Microbiology. Ses. No. 263/Z. Abstract. Z-45. pg. 748 Technical Abstract: Resistance to 3rd generation cephalosporins in Salmonella isolates from humans and animals has emerged as a public health concern. We examined a group of ecphalosporin resistant isolates from various animal sources submitted to the National Antimicrobial Resistance Monitoring System. Twenty-two isolates from testing year 1997 were analyzed each of which had MIC's to Ceftriaxone, Ceftiofur, and Cephalothin of >/=32, >/=64 and >/=32, respectively. The serotypes of the isolates in this group were typhimurium-copenhagen (7), typhimurium (7), bredeney (3), ohio (2), montevideo (2) and agona (1). Isolates were recovered from nearly all domestic species including cattle (2), swine (2), chickens (1), horses (1) cats (3) and turkeys (13). Interestingly, the majority of these isolates were found to be resistant to multiple antimicrobials. Of the 22 isolates 82% were found to be resistant to 8 or more of 17 antimicrobials and 68% of the isolates were resistant to 10 or more antimicrobials as compared to 0.8% of the general population (n=2391) of Salmonella isolates tested having resistance to 10 or more antimicrobials. Seventy seven percent (17) of the isolates were resistant to amoxicillin-clavulanic acid. The most common non beta- lactam resistances were ticarcillin (91%), tetracycline (82%), streptomycin (82%), kanamycin (77%), sulfamethoxazole (77%), cholramphenicol (63%) and gentamicin (59%). None of the isolates were phage type DT104. Isolates were examined for cephalosporin resistance mechanisms, 19 of 22 isolates were found to have an AmpC like beta- lactamase and tested positive for the ampC gene by PCR, 2 of the isolates had a putative ESBL.