Welch W D, Lu Y S, Bawdon R E
Lab Anim Sci. 1987 Feb;37(1):65-8.
Treatment of infections due to Pasteurella multocida in rabbits usually consists of a single intramuscular injection of penicillin G and results in variable cure rates. We report here the levels of penicillin G in serum and nasal washings in P. multocida free and P. multocida infected rabbits following a single intramuscular injection over a 24 hours period. These levels were compared to the minimal inhibitory concentrations (MICS) of 50 clinical isolates of P. multocida of rabbit origin. Infected rabbits demonstrated higher serum levels of penicillin G over P. multocida free rabbits at 1, 3, and 5 hours after the injection. At 16 and 24 hours the penicillin G serum levels dropped to 0.14 and 0.07 microgram/ml, respectively, from 1.90 micrograms/ml at 8 hours. At these levels of penicillin G only 20% of the isolates tested in vitro for susceptibilities (MICs) would be inhibited. Levels of penicillin G in nasal washings at 4 hours after injection were 0.063 microgram/ml, or one-fourth the MIC of 80% of the P. multocida isolates tested (0.25 microgram/ml). In contrast, serum levels of approximately 5 micrograms/ml were seen at this time. Our results suggest that therapeutic blood levels could be achieved if rabbits are given injections of procaine penicillin G at 8 hour intervals.
家兔多杀性巴氏杆菌感染的治疗通常是单次肌内注射青霉素G，治愈率各不相同。我们在此报告了在24小时内单次肌内注射后，无多杀性巴氏杆菌感染和有多杀性巴氏杆菌感染的家兔血清及鼻腔灌洗液中的青霉素G水平。将这些水平与50株兔源多杀性巴氏杆菌临床分离株的最低抑菌浓度（MICs）进行了比较。感染的家兔在注射后1、3和5小时血清中的青霉素G水平高于未感染多杀性巴氏杆菌的家兔。在16和24小时，青霉素G血清水平分别从8小时时的1.90微克/毫升降至0.14和0.07微克/毫升。在这些青霉素G水平下，体外测试药敏性（MICs）的分离株中只有20%会受到抑制。注射后4小时鼻腔灌洗液中的青霉素G水平为0.063微克/毫升，即80%受试多杀性巴氏杆菌分离株MIC（0.25微克/毫升）的四分之一。相比之下，此时血清水平约为5微克/毫升。我们的结果表明，如果每隔8小时给家兔注射普鲁卡因青霉素G，可达到治疗所需的血药浓度。
