tiamulin and Respiratory-Tract-Infections

The in vitro activities of 12 quinolones and four antibiotics were determined against 15 veterinary mycoplasmal species and four species of bacteria commonly involved in respiratory infections in pigs. The newer quinolones were markedly more active in vitro against a wide range of mycoplasmas than nalidixic acid and the earlier quinolones. Against Mycoplasma hyopneumoniae ciprofloxacin was the most active quinolone with a geometric mean minimal inhibitory concentration (MIC) against 16 strains of 0.01 microgram ml-1 compared with 0.04 microgram ml-1 for tiamulin, 0.06 microgram ml-1 for tylosin, 0.17 microgram ml-1 for oxytetracycline and 0.23 microgram ml-1 for gentamicin. M hyosynoviae was less sensitive to the quinolones with mean MICs of 0.6 microgram ml-1 for ofloxacin and 0.7 microgram ml-1 for ciprofloxacin compared with 0.034 microgram ml-1, or less, for tiamulin. Norfloxacin and its 6-chloro analogue were both mycoplasmacidal in vitro at five or 10 times their MICs against M hyopneumoniae UCD4. Tiamulin was mycoplasmastatic. The quinolones were also active against porcine Bordetella bronchiseptica and Pasteurella multocida strains and Haemophilus species. Ciprofloxacin was the most active quinolone with mean MICs of 0.58 microgram ml-1 against B bronchiseptica (nine strains), 0.026 microgram ml-1 against P multocida (five strains) and 0.01 microgram ml-1, or less, against Haemophilus pleuropneumoniae (nine strains) and H parasuis (two strains) compared with mean MICs of from 0.5 microgram ml-1 to 64 micrograms ml-1, or more, for the antibiotics. This combination of excellent mycoplasmacidal activity against M hyopneumoniae and good antibacterial activity, suggests that the quinolones have great potential for treating respiratory infections in pigs, including enzootic pneumonia.

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Bordetella; Diterpenes; Gentamicins; Haemophilus; Microbial Sensitivity Tests; Mycoplasma; Norfloxacin; Pasteurella; Respiratory Tract Infections; Swine; Swine Diseases; Time Factors

A group of six racing pigeons naturally infected with Mycoplasma columborale and M columbinum were housed in isolation and treated with tiamulin hydrogen fumarate in the drinking water for 35 days. Swabs from the oropharynx, the oesophagus and the trachea were negative for mycoplasmas at the end of this period. Mycoplasmas were recovered from two of the birds after a further nine days, and 13 weeks after the cessation of treatment mycoplasmas were recovered from all six birds.

Topics: Animals; Bird Diseases; Columbidae; Diterpenes; Female; Male; Mycoplasma; Mycoplasma Infections; Respiratory Tract Infections; Species Specificity