Effect Found in the Combination of Kitasamycin with Other Antibiotics Used against <i>Actinobacillus pleuropneumoniae</i>

Background: Combinations of antibiotics are used to increase the therapeutic options via the simultaneous activities of two compounds. The goals of combination therapy are to resolve the bacterial infection while reducing the treatment cost. The use of kitasamycin is used frequently and in addition to other antibiotics, the desired combinations were not found. Methods: Fields strains: we use serotypes 1, 3, 5 y 7. Microbial culturing: The serotypes 1, 3, 5 y 7 was identified. Antibiotics and Reagents: The antibiotics used were kitasamycin;enrofloxacin and oxolinic acid. The following combinations were tested: a) kitasamycin with enrofloxacin;b) kitasamycin with norfloxacin;and c) kitasamycin with oxolinic acid. Preparation of bacterial suspensions: The cultures were adjusted to a concentration of 5 colony-forming units per ml (CFU/ml) using the same sterile culture medium as the diluent. Determination of the fractional inhibitory concentrations (FICs): To test each combination and their interactions and to calculate the fractional inhibitory concentration (FIC) of each antibiotic. Calculation of the index of the fractional minimum inhibitory concentration (FMIC): The FMIC index was calculated by applying the following formula: FIC index = FIC of antibiotic A/FIC of antibiotic B. Results: What was found showed that: A combination of kitasamycin and norfloxacin has been shown to have an indifferent effect. A combination of kitasamycin and enrofloxacin had antagonistic effects against all of the Actinobacillus pleuropneumoniae serotypes studied. Finally, a combination of kitasamycin and oxolinic acid had antagonist effects against serotypes 1, 3 and 5 and a synergistic effect against serotype 7. Conclusion: The “in vitro” combination Kitasamycin-Norfloxacin showed an indifferent effect, and combination Kitasamycin and Enrofloxacin demonstrated an antagonistic interaction between these two antibiotics. A combination of Kitasamycin and Oxolinic Acid had synergistic effect against serotype 7.

Pathology Isolation and Identification of Canine Herpesvirus (CHV-1) in Mexico

This work presents the pathology description, isolation and identification of canine herpesvirus (CHV-1) in Mexico, a virus that causes a generalized hemorrhagic infection in puppies from the canidae family. Methods: Isolates were obtained from puppies that died within the first four weeks of life and had lesions consistent with canine herpesvirus. Results: The main gross lesions were petechial and ecchymotic hemorrhages in kidneys, liver and lungs;proliferative interstitial nephritis;multifocal necrosis in liver and kidneys;and encephalitis with intranuclear inclusion bodies. Herpesvirus was confirmed through direct immunofluorescence, electron microscopy and polymerase chain reaction for DNA polymerase and glycoprotein B genes. Discussion: Eight strains were isolated and identified as canine herpesvirus corresponding to three of the working cases with gross and microscopic lesions very similar to those described in the literature;then, isolates were confirmed by PCR gene amplification, positive reactions on immunofluorescence and observations from electron microscopy. This work represents the first report of this disease, including gross and histological lesions, and confirmation by isolation and identification of the canine herpesvirus in Mexico.