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Marbofloxacin (MB) is a secondgeneration fluoroquinolone widely used in veterinary medicine to treat respiratory diseases in pigs. To our knowledge, there is no information available on how antibiotic treatment affects the colonization of Haemophilus parasuis. Taking into account that fluoroquinolones are usually used to treat respiratory diseases in pigs, the goals of the present work are to study the colonization of H. parasuis in pigs treated with 8 mg/kg body weight (bw) dose of marbofloxacin in one shot.
The study was carried out in a farm with clinical cases of Glässer’s disease. 300 4-week-old crossbred pigs were randomly divided in two groups and placed in independent rooms with independent ventilation. Treatment group received 8 mg MB⁄ kg bw in one shot. Animals of the control group were sham injected intramuscularly with the same volume of physiological saline. Treatments were applied at the beginning of the nursery period. 20 piglets of each group were randomly selected and tagged. Nasal swabs from those selected piglets were taken on days 0, 1, 7, 14 and 28 after administering the antibiotic. The swabs were processed for DNA extraction and the extracted DNA was used in a species-specific PCR to identify H. parasuis2.
Seventeen and twenty animals were used for control and treatment group throughout the trial, respectively because three animals of the control group died and they were excluded from the study. Significant differences between both groups were found at 1 and 7 days after treatment. However, at days 14 and 28 post-treatment the difference in H. parasuis colonization between the groups disappeared.
The treatment with marbofloxacin at a dose of 8 mg/kg body weight in one shot by intramuscular route reduced the percentage of positive animals to H. parasuis in the nasal cavity during short periods of time after the application of this antibiotic. This result indicates that this treatment may be useful to control the disease produced by this bacteria both at individual and population basis although a complete elimination of the bacteria was not possible.
Carles Vilalta, Nuria Galofré, Virginia Aragon, Ana María Pérez de Rozas, Lorenzo Fraile. Effect of marbofloxacin treatment on Haemophilus parasuis colonization. 22nd IPVS, 2012.
