Antimicrobial susceptibility of Riemerella anatipestifer isolated from ducks and the efficacy of ceftiofur treatment.
The in vitro susceptibilities of 50 field isolates of Riemerella anatipestifer from ducks to ceftiofur and 16 other commonly used antimicrobials were determined. The MIC90 values (MIC refers to minimum inhibitory concentrations) for the antimicrobials used in this study are as follows: penicillin was 16 microg/ml; ceftiofur was 32 microg/ml; cephalothin, chloramphenicol, flumequine, and kanamycin were 64 microg/ml; nalidixic acid, nitrofurantoin, and sulfamethoxazole were 128 microg/ml; amikacin, ampicillin, gentamicin, lincomycin, spectinomycin, streptomycin, tetracycline, and trimethoprim were > or = 256 microg/ml. The therapeutic efficacy of ceftiofur against a highly lethal experimental R. anatipestifer infection in ducks was also evaluated. All experimental ducks were infected through the infraorbital sinus with 1 ml of 9 x 10(9) CFU of R. anatipestifer. Ceftiofur (0, 0.25, 0.5, 1, and 2 mg/kg) was injected subcutaneously 5 hours after infection. A single dose of 2 mg/kg resulted in 73% survival as compared with 10% survival in the infected, but untreated controls.
Chang
Chao-Fu
CF
Department of Veterinary Medicine, National Taiwan University, 142 ZhouShan Road, Taipei 106, Taiwan.
Lin
Wen-Hwa
WH
Yeh
Tung-Mao
TM
Chiang
Tai-Sheng
TS
Chang
Yung-Fu
YF
D000818:Animals; D002511:Cephalosporins / Q000494:pharmacology* / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial; D004372:Ducks / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality / Q000662:veterinary; D008826:Microbial Sensitivity Tests; D011201:Poultry Diseases / Q000188:drug therapy / Q000382:microbiology* / Q000401:mortality
D002511:Cephalosporins; C053503:ceftiofur