tiamulin and ceftiofur

It addition to their antimicrobial properties, antibiotics can influence the host immune system (modulation of cytokine secretion, antibody production and T-cell proliferation). In the present study, the authors studied the effects of therapeutic doses of amoxicillin (AMX), ceftiofur (CEF), doxycycline (DOXY), tiamulin (TIAM) and tulathromycin (TUL) on the postvaccinal immune response after pigs had been vaccinated against erysipelas. Because humoral immunity is considered as the most important in the protection against swine erysipelas, the present study focused on the interactions between antibiotics and postvaccinal humoral immunity. One hundred and five, eight-week-old pigs of both sexes were used. Specific antibodies to the Erysipelothrix rhusiopathiae antigen were determined using a commercial ELISA test. In pigs treated with DOXY or CEF or TIAM, a significant reduction in the number of positive pigs was observed four and six weeks after the second dose of vaccine, compared with the remaining vaccinated groups. In pigs treated with CEF, the ELISA score was significantly lower than in non-treated vaccinated pigs. While in vaccinated pigs treated with AMX or TUL, the ELISA score was significantly higher than in pigs treated with the remaining antibiotics and than in non-treated vaccinated controls. The results of the present study indicate that vaccination of pigs against erysipelas in the presence of antibiotics may result in a decrease (CEF, DOXY, TIAM) or enhancement (AMX, TUL) in the production of specific antibodies.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Bacterial Vaccines; Cephalosporins; Disaccharides; Diterpenes; Doxycycline; Female; Heterocyclic Compounds; Immunity, Humoral; Male; Swine; Swine Erysipelas

Seventy-six, crossbred, porcine reproductive and respiratory syndrome virus (PRRSV)-free pigs were weaned at 12 days of age and randomly assigned to seven groups of 10 to 11 pigs each. Pigs in group 1 served as unchallenged controls. Pigs in groups 2 to 7 were challenged intranasally with 2 ml of high-virulence PRRSV isolate VR-2385 (10(4.47) 50% tissue culture infective doses per 2 ml) on day 0 of the study (30 days of age). Seven days after PRRSV challenge, pigs in groups 2 to 7 were challenged intranasally with 2 ml of Streptococcus suis serotype 2 (10(8.30) CFU/2 ml). Group 2 pigs served as untreated positive controls. Antimicrobial treatments included daily intramuscular injection with 66,000 IU of procaine penicillin G per kg of body weight on days 8 to 10 (group 3), drinking water medication with 23.1 mg of tiamulin per kg during days 8 to 10 (group 4), and daily intramuscular injection of 5.0 mg of ceftiofur hydrochloride per kg on days 8 to 10 (group 5). Vaccination regimens included two intramuscular doses of an autogenous killed S. suis vaccine (group 6) prior to S. suis challenge or a single 2-ml intramuscular dose of an attenuated live PRRSV vaccine (group 7) 2 weeks prior to PRRSV challenge. Mortality was 0, 63, 45, 54, 9, 40, and 81% in groups 1 to 7, respectively. Ceftiofur treatment was the only regimen that significantly (P < 0. 05) reduced mortality associated with PRRSV and S. suis coinfection. The other treatments and vaccinations were less effective. We conclude that ceftiofur administered by injection for three consecutive days following S. suis challenge was the most effective regimen for minimizing disease associated with PRRSV and S. suis coinfection.

Topics: Animals; Anti-Bacterial Agents; Antibiotic Prophylaxis; Cephalosporins; Diterpenes; Injections, Intramuscular; Penicillin G Procaine; Porcine Reproductive and Respiratory Syndrome; Porcine respiratory and reproductive syndrome virus; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases; Viral Vaccines; Virulence; Water Supply

This study was conducted to compare the applicability of three different media in sensitivity testing of Actinobacillus pleuropneumoniae by means of MIC and tablet diffusion tests. The media used were: modified PPLO agar, chocolatized Mueller-Hinton-II and Columbia agar supplemented with NAD. Seven antimicrobial agents were tested: ceftiofur, enrofloxacin, penicillin, spectinomycin, tiamulin, trimethoprim + sulfadiazine and tylosin, against 40 randomly selected A. pleuropneumoniae isolates. In general, good agreement was found between results obtained with all combinations of media, most antimicrobials tested and the two-test systems. Some variations between media were observed for spectinomycin, tiamulin and tylosin. For ceftiofur and trimethoprim + sulfadiazine some isolates with low MIC-values were classified as resistant using tablet diffusion, indicating that the break points of resistance for these antimicrobials using the tablet diffusion tests need adjustment. Using current break points for resistance with MIC-determinations, all isolates tested susceptible to ceftiofur, enrofloxacin, penicillin, tiamulin and trimethoprim + sulfadiazine. A larger number of isolates tested resistant to spectinomycin and tylosin on all three media using both MIC determinations and tablet diffusion.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Cephalosporins; Colony Count, Microbial; Culture Media; Diterpenes; Drug Combinations; Drug Resistance, Microbial; Enrofloxacin; Fluoroquinolones; Latex Fixation Tests; Microbial Sensitivity Tests; Penicillins; Quinolones; Spectinomycin; Sulfadiazine; Swine; Swine Diseases; Trimethoprim; Tylosin

SPF pigs aged 10 weeks were infected intranasally with Actinobacillus pleuropneumoniae serotype 2. After the onset of clinical symptoms of respiratory disease, which occurred 20 h post-infection, parenteral treatment with ceftiofur, danofloxacin, enrofloxacin, penicillin or tiamulin was initiated (n = 8 per group). Untreated groups, of which one was infected, served as controls. The uninfected control group did not show any signs of disease, while the infected control group was severely affected by the infection and also expressed a decreased weight gain following the challenge. Based on clinical signs, the magnitude of pathological lesions in the respiratory tract found at necropsy performed 17 days post-infection and the number of reisolates of A. pleuropneumoniae made at necropsy, treatments with the quinolones (danofloxacin and enrofloxacin) and the cephalosporine (ceftiofur) were superior to those with penicillin and tiamulin. The latter groups also developed antibodies to A. pleuropneumoniae to a larger extent. Some of the pigs treated with ceftiofur and danofloxacin developed antibodies to A. pleuropneumoniae, and the microbe was reisolated from approximately 50% of these animals. In contrast, pigs treated with enrofloxacin did not develop antibodies to A. pleuropneumoniae, and the challenge strain was not found at necropsy. The performance with respect to daily weight gain and feed conversion corresponded well with the clinical signs developed and the findings made at necropsy. The decreased growth recorded during the acute phase of the disease was, to a large extent, caused by a reduced feed intake.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Body Weight; Cephalosporins; Diterpenes; Enrofloxacin; Fluoroquinolones; Lung; Lung Diseases; Penicillins; Quinolones; Swine; Swine Diseases; Weight Gain