[Show abstract][Hide abstract] ABSTRACT: The effect of vaccination of chickens with different inactivated vaccines against experimental Ornithobacterium rhinotracheale challenge was investigated. Eight different vaccines, with different inactivating substances (Formalin and thiomersal) and with or without adjuvant (mineral oil, alum and aluminium hydroxide gel), were produced. Following vaccination of experimental chickens at week 8 with formalin-inactivated mineral oil adjuvant bacterin, the mean O. rhinotracheale antibody titres rose to 5.88 2log 21 days after primary vaccination and enhanced to a titre of 6.59 2log 21 days after booster vaccination. The bacterin in mineral oil adjuvant induced the highest serologic response and a significant decrease of lesions such as air sacculitis and pneumonia in vaccinated birds compared with the unvaccinated challenge control birds. The bacterin in either alum or aluminium hydroxide gel adjuvant induced a moderate serologic response and a decrease of lesions compared with the unvaccinated challenge controls. The study showed that vaccination of layer chicken at the eighth week followed by a booster dose at the 12th week of age can effectively protect against O. rhinotracheale infections.
[Show abstract][Hide abstract] ABSTRACT: Eighteen isolates of Ornithobacterium rhinotracheale isolated from laying hens in India were tested for their susceptibility to various antibiotic agents. Antibiogram pattern of all the 18 O. rhinotracheale isolates were determined in Mueller Hinton agar enriched with 10 per cent sheep blood, with antibiotic discs. All the isolates were resistant to amikacin, cloxacillin, co-trimoxazole, gentamicin, metronidazole and triple sulpha. Susceptibility of O. rhinotracheale isolates to cephalexin, norfloxacin, pefloxacin, streptomycin and furazolidone was variable. The isolates were sensitive to amoxycillin, ampicillin, chloramphenicol, ciprofloxacin, doxycycline, enrofloxacin, erythromycin, oxytetracycline, and penicillin-G.