-
Journal of Veterinary Pharmacology and... Apr 2018The combined antibacterial effects of tilmicosin (TIL) and florfenicol (FF) against Actinobacillus pleuropneumoniae (APP) (n = 2), Streptococcus suis (S. suis)...
The combined antibacterial effects of tilmicosin (TIL) and florfenicol (FF) against Actinobacillus pleuropneumoniae (APP) (n = 2), Streptococcus suis (S. suis) (n = 2), and Haemophilus parasuis (HPS) (n = 2) were evaluated by chekerboard test and time-kill assays. The pharmacokinetics (PKs) of TIL- and FF-loaded hydrogenated castor oil (HCO)-solid lipid nanoparticles (SLN) were performed in healthy pigs. The results indicated that TIL and FF showed synergistic or additive antibacterial activities against APP, S. suis and HPS with the fractional inhibitory concentration (FIC) ranging from 0.375 to 0.75. The time-kill assays showed that 1/2 minimum inhibitory concentration (MIC) TIL combined with 1/2 MIC FF had a stronger ability to inhibit the growth of APP, S. suis, and HPS than 1 MIC TIL or 1 MIC FF, respectively. After oral administration, plasma TIL and FF concentrations could maintain about 0.1 μg/ml for 192 and 176 hr. The SLN prolonged the last time point with detectable concentrations (T ), area under the concentration-time curve (AUC ), elimination half-life (T ), and mean residence time (MRT) by 3.1, 5.6, 12.7, 3.4-fold of the active pharmaceutical ingredient (API) of TIL and 11.8, 16.5, 18.1, 12.1-fold of the API of FF, respectively. This study suggests that the TIL-FF-SLN could be a useful oral formulation for the treatment of APP, S. suis, and HPS infection in pigs.
Topics: Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Castor Oil; Drug Combinations; Drug Synergism; Haemophilus parasuis; Hydrogenation; Male; Microbial Sensitivity Tests; Nanoparticles; Streptococcus suis; Swine; Swine Diseases; Thiamphenicol; Tylosin
PubMed: 29139136
DOI: 10.1111/jvp.12465 -
Veterinary Microbiology Jun 2017Pigs (Sus scrofa) were introduced to Guam in the 1600's and are now present in high densities throughout the island. Wild pigs are reservoirs for pathogens of concern to...
Pigs (Sus scrofa) were introduced to Guam in the 1600's and are now present in high densities throughout the island. Wild pigs are reservoirs for pathogens of concern to domestic animals and humans. Exposure to porcine parvovirus, transmissible gastroenteritis, and Leptospira interrogans has been documented in domestic swine but data from wild pigs are lacking. The close proximity of humans, domestic animals, and wild pigs, combined with the liberal hunting of wild pigs, results in frequent opportunities for pathogen transmission. From February-March 2015, blood, tissue and ectoparasite samples were collected from 47 wild pigs. Serologic testing found exposure to Brucella spp. (2%), Toxoplasma gondii (11%), porcine reproductive and respiratory syndrome (PRRS) virus (13%), porcine circovirus type 2 (36%), pseudorabies virus (64%), Actinobacillus pleuropneumoniae (93%), Lawsonia intracellularis (93%), and porcine parvovirus (94%). Eleven (24%) samples had low titers (1:100) to Leptospira interrogans serovars Bratislava (n=6), Icterohaemorrhagiae (n=6), Pomona (n=2), and Hardjo (n=1). Kidney samples from nine pigs with Leptospira antibodies were negative for Leptospira antigens. Numerous pigs had Metastrongylus lungworms and three had Stephanurus dentatus. Lice (Hematopinus suis) and ticks (Amblyomma breviscutatum) were also detected. No antibodies to Influenza A viruses were detected. In contrast to the previous domestic swine survey, we found evidence of numerous pathogens in wild pigs including new reports of pseudorabies virus, PRRS virus, Brucella, and Leptospira in pigs on Guam. These findings highlight that domestic swine-wild pig interactions should be prevented and precautions are needed when handling wild pigs to minimize the risk of pathogen transmission.
Topics: Actinobacillus pleuropneumoniae; Animals; Circovirus; Epidemiological Monitoring; Female; Guam; Herpesvirus 1, Suid; Lawsonia Bacteria; Male; Porcine respiratory and reproductive syndrome virus; Surveys and Questionnaires; Swine; Swine Diseases; Toxoplasma
PubMed: 28622856
DOI: 10.1016/j.vetmic.2017.05.001 -
Veterinary Microbiology May 2017Epidemiologic data from Asian outbreaks of highly-pathogenic (HP) porcine reproductive and respiratory syndrome virus (PRRSV) suggest that disease severity was... (Comparative Study)
Comparative Study
Comparison of Asian porcine high fever disease isolates of porcine reproductive and respiratory syndrome virus to United States isolates for their ability to cause disease and secondary bacterial infection in swine.
Epidemiologic data from Asian outbreaks of highly-pathogenic (HP) porcine reproductive and respiratory syndrome virus (PRRSV) suggest that disease severity was associated with both the virulence of the PRRSV isolates and secondary bacterial infections. Previous reports have indicated that U.S. isolates of PRRSV predispose to secondary bacterial infections as well, but the severity of disease that occurred in Asia in pigs infected with these HP-PRRSV strains has not been reported in the U.S. The objectives of this research were to compare the pathogenesis of Asian and U.S. PRRSV isolates with regard to their ability to cause disease and predispose to secondary bacterial infections in swine. To address these objectives groups of pigs were infected with 1 of 2 Asian HP-PRRSV strains (rJXwn06 or rSRV07) or 1 of 2 U.S. PRRSV strains (SDSU73 or VR-2332) alone or in combination with Streptococcus suis, Haemophilus parasuis, and Actinobacillus suis. Pigs infected with rJXwn06 exhibited the most severe clinical disease while the pigs infected with rSRV07 and SDSU73 exhibited moderate clinical disease, and pigs infected with VR-2332 exhibited minimal clinical signs. The frequency of secondary bacterial pneumonia was associated with the clinical severity induced by the PRRSV strains evaluated. The levels of proinflammatory cytokines in the serum were often lower for pigs coinfected with virus and bacteria compared to pigs infected with PRRSV alone indicating an alteration in the immune response in coinfected pigs. Combined our results demonstrate that severity of disease appears to be dependent on virulence of the PRRSV strain, and development of secondary bacterial infection.
Topics: Animals; Coinfection; Disease Susceptibility; Female; Haemophilus Infections; Haemophilus parasuis; Lung; Porcine Reproductive and Respiratory Syndrome; Porcine respiratory and reproductive syndrome virus; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases; Viremia; Virulence
PubMed: 28619168
DOI: 10.1016/j.vetmic.2017.02.003 -
Veterinary Microbiology May 2017This study investigated the cause of recent outbreaks of septicaemia in neonatal pigs in Australia (Victoria and Queensland). Septicaemia in neonatal pigs is commonly...
This study investigated the cause of recent outbreaks of septicaemia in neonatal pigs in Australia (Victoria and Queensland). Septicaemia in neonatal pigs is commonly caused by enterotoxigenic E. coli, extraintestinal pathogenic E. coli and beta-haemolytic streptococci. Infrequent causes of septicaemia are Actinobacillus suis and Citrobacter freundii. Therefore, it was quite unexpected when Klebsiella pneumoniae was isolated in predominant growth from multiple organs of pigs dying of septicaemia from six days of age. Two cases in Victoria were associated with multilocus sequence type 25 (ST25), whereas the cases on a single farm in Queensland were associated with two different sequence types (ST278 and ST1978). Similar outbreaks of septicaemia have also occurred in England, but all were associated with K. pneumoniae ST25. The K. pneumoniae sequence types did not cluster phylogenetically into groups of isolates from the same geographical location or into groups which caused either septicaemia or pneumonia. Antibiotic resistance also varied between isolates and showed neomycin resistance in Queensland. These results suggest that several sequence types of K. pneumoniae are involved in causing outbreaks of septicaemia in neonatal pigs, in addition to its previously recognised role in pneumonia and mastitis.
Topics: Animals; Animals, Newborn; Bacterial Typing Techniques; Disease Outbreaks; Klebsiella Infections; Klebsiella pneumoniae; Multilocus Sequence Typing; Pneumonia; Sepsis; Swine
PubMed: 28619154
DOI: 10.1016/j.vetmic.2017.03.018 -
Frontiers in Pharmacology 2017A new, more palatable formulation of 10% enrofloxacin enteric-coated granules was investigated to evaluate the pharmacokinetic effect in plasma, the residue elimination...
A new, more palatable formulation of 10% enrofloxacin enteric-coated granules was investigated to evaluate the pharmacokinetic effect in plasma, the residue elimination in tissues and the clinical efficacy against and in pigs. In this study, the enrofloxacin concentrations in plasma and tissues were detected using high-performance liquid chromatography with phosphate buffer (pH = 3) and acetonitrile. The pharmacokinetics and elimination of enrofloxacin enteric-coated granules were performed after oral administration at a single dose of 10 mg/kg body weight (bw) and 5 mg/kg twice per day for 5 consecutive days, respectively. The antibacterial efficacy and clinical effectiveness of enrofloxacin enteric-coated granules against and were assayed at 2.5, 5, 10 mg/kg, compared with tiamulin (8 mg/kg) based on establishment of and infection models. 56 strains were selected and tested for antibacterial activity of enrofloxacin enteric-coated granules. The main parameters of elimination half-life (t), T, and area under the curve (AUC) were 14.99 ± 4.19, 3.99 ± 0.10, and 38.93 ± 1.52 μg h/ml, respectively, revealing that the enrofloxacin concentration remained high and with a sustainable distribution in plasma. Moreover, the analysis on the evaluation of enrofloxacin and ciprofloxacin in muscle, fat, liver and kidney showed that the recovery were more than 84% recovery in accordance with the veterinary drug residue guidelines of United States pharmacopeia, and the withdrawal periods were 4.28, 3.81, 4.84, and 3.51 days, respectively, suggesting that the withdrawal period was 5 d after oral administration of 5 mg/kg twice per day. The optimal dosage of enrofloxacin enteric-coated granules against and was 5 mg/kg, with over 90% efficacy, which was significantly different ( < 0.05) to the 2.5 mg/kg group, but not to the 10 mg/kg group or the positive control group (tiamulin). In conclusion, 10% enrofloxacin enteric-coated granules had significant potential for treating and , and it provided an alternative enrofloxacin palatability formulation.
PubMed: 28588496
DOI: 10.3389/fphar.2017.00294 -
The Veterinary Record Jun 2017A monitoring programme of marbofloxacin susceptibility of bacteria from Europe causing respiratory tract infection and meningitis in pigs has been active since 1994 and...
A monitoring programme of marbofloxacin susceptibility of bacteria from Europe causing respiratory tract infection and meningitis in pigs has been active since 1994 and 2002, respectively. Monitoring digestive, metritis and urinary tract infection (UTI) in pigs has been active since 2005 and susceptibility results until 2013 are presented. Minimum inhibitory concentration (MIC) was determined by broth microdilution. For MIC interpretation, Vétoquinol-evaluated breakpoints were applied. For digestive pathogens, and species (1717 and 300 isolates, respectively) exhibited 7.5 per cent resistance in and no resistance in species. Similarly, from metritis (369 isolates) had 7.0 per cent resistance to marbofloxacin. However, from UTI (633 isolates) had higher resistance (10.4 per cent). For causing meningitis (585 isolates), marbofloxacin susceptibility was very high with only 0.5 per cent resistance and 0.4 per cent resistance was observed with causing respiratory disease (729 isolates). Other respiratory pathogens were also highly susceptible to marbofloxacin with no resistance in (647 isolates) or (504 isolates), 0.1 per cent resistance in (1373 isolates) and 1.4 per cent resistance in (145 isolates). There was no apparent change in marbofloxacin MIC over time for any bacterial pathogen based on MIC These data confirm previously published MIC results from porcine and other animal infections.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Drug Resistance, Bacterial; Europe; Fluoroquinolones; Microbial Sensitivity Tests; Swine; Swine Diseases; Treatment Outcome
PubMed: 28348142
DOI: 10.1136/vr.103954 -
Veterinary Microbiology Nov 2016Actinobacillus suis is an opportunistic pathogen that resides in the tonsils of the soft palate of swine. Unknown stimuli can cause this organism to invade the host,...
Actinobacillus suis is an opportunistic pathogen that resides in the tonsils of the soft palate of swine. Unknown stimuli can cause this organism to invade the host, resulting in septicaemia and sequelae including death. To better understand its pathogenesis, the expression of several adhesin genes was evaluated by semi-quantitative real-time PCR in A. suis grown in conditions that mimic the host environment, including different nutrient and oxygen levels, exponential and stationary phases of growth, and in the presence of the stress hormone epinephrine. Fifty micromolar epinephrine did not affect the growth rate or expression of A. suis adhesin genes, but there was a significant growth phase effect for many genes. Most adhesin genes were also differentially expressed during anoxic static growth or aerobic growth, and in this study, all genes were differentially expressed in either exponential or stationary phase. Based on the time*treatment interactions observed in the anoxic study, a model of persistence of A. suis in the host environment in biofilm and planktonic states is proposed. Biofilm dynamics were further studied using wild type and isogenic mutants of the type IVb pilin (Δ flp1), the OmpA outer membrane protein (ΔompA), and the fibronectin-binding (ΔcomE1) genes. Disruption of these adhesin genes affected the early stages of biofilm formation, but in most cases, biofilm formation of the mutant strains was similar to that of the wild type by 24h of incubation. We postulate that other adhesins may have overlapping functions that can compensate for those of the missing adhesins.
Topics: Actinobacillus suis; Adhesins, Bacterial; Bacteriological Techniques; Biofilms; Gene Expression Regulation, Bacterial
PubMed: 27771071
DOI: 10.1016/j.vetmic.2016.09.005 -
Acta Veterinaria Scandinavica Oct 2016Respiratory illness is traditionally regarded as the disease of the growing pig, and has historically mainly been associated to bacterial infections with focus on...
BACKGROUND
Respiratory illness is traditionally regarded as the disease of the growing pig, and has historically mainly been associated to bacterial infections with focus on Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. These bacteria still are of great importance, but continuously increasing herd sizes have complicated the scenario and the influence of secondary invaders may have been increased. The aim of this study was to evaluate the presence of A. pleuropneumoniae and M. hyopneumoniae, as well as that of the secondary invaders Pasteurella multocida and Streptococcus suis by serology in four pig herds (A-D) using age segregated rearing systems with high incidences of pleuritic lesions at slaughter.
RESULTS
Pleuritic lesions registered at slaughter ranged from 20.5 to 33.1 % in the four herds. In herd A, the levels of serum antibodies to A. pleuropneumoniae exceeded A > 1.5, but not to any other microbe searched for. The seroconversion took place early during the fattening period. Similar levels of serum antibodies to A. pleuropneumoniae were also recorded in herd B, with a subsequent increase in levels of antibodies to P. multocida. Pigs seroconverted to both agents during the early phase of the fattening period. In herd C, pigs seroconverted to P. multocida during the early phase of the fattening period and thereafter to A. pleuropneumoniae. In herd D, the levels of antibodies to P. multocida exceeded A > 1.0 in absence (A < 0.5) of antibodies to A. pleuropneumoniae. The levels of serum antibodies to M. hyopneumoniae and to S. suis remained below A < 1.0 in all four herds. Pigs seroconverted to M. hyopneumoniae late during the rearing period (herd B-D), or not at all (herd A).
CONCLUSION
Different serological patterns were found in the four herds with high levels of serum antibodies to A. pleuropneumoniae and P. multocida, either alone or in combination with each other. Seroconversion to M. hyopneumoniae late during the rearing period or not at all, confirmed the positive effect of age segregated rearing in preventing or delaying infections with M. hyopneumoniae. The results obtained highlight the necessity of diagnostic investigations to define the true disease pattern in herds with a high incidence of pleuritic lesions.
Topics: Actinobacillus pleuropneumoniae; Animal Husbandry; Animals; Antibodies, Bacterial; Bacterial Infections; Mycoplasma hyopneumoniae; Pasteurella multocida; Pleurisy; Seroconversion; Streptococcus suis; Swine; Swine Diseases; Time Factors
PubMed: 27716292
DOI: 10.1186/s13028-016-0252-1 -
Journal of Veterinary Science Sep 2017Oral fluid analysis for herd monitoring is of interest to the commercial pig production in Korea. The aim of this study was to investigate pathogen-positive rates and...
Oral fluid analysis for herd monitoring is of interest to the commercial pig production in Korea. The aim of this study was to investigate pathogen-positive rates and correlations among eight pathogens associated with porcine respiratory disease complex by analyzing oral fluid samples from 214 pig groups from 56 commercial farms. Samples collected by a rope-chewing method underwent reverse-transcriptase polymerase chain reaction (RT-PCR) or standard polymerase chain reaction (PCR) analysis, depending on the microorganism. Pathogens were divided into virus and bacteria groups. The former consisted of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 (PCV2), and the latter , , , (MHP), , and (SS). All pathogens were detected more than once by PCR. Age-based analysis showed the PCR-positive rate increased with increasing age for PCV2 and MHP, whereas SS showed the opposite. Correlations between pathogens were assessed among 36 different pair combinations; only seven pairs showed statistically significant correlations. In conclusion, the oral fluid method could be a feasible way to detect various swine respiratory disease pathogens and, therefore, could complement current monitoring systems for respiratory diseases in the swine industry.
Topics: Animals; Farms; Mouth; Porcine Reproductive and Respiratory Syndrome; Porcine respiratory and reproductive syndrome virus; Republic of Korea; Reverse Transcriptase Polymerase Chain Reaction; Surveys and Questionnaires; Swine
PubMed: 27586468
DOI: 10.4142/jvs.2017.18.3.283 -
Infection and Immunity Oct 2016Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and...
Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and invasion of bacterial pathogens. Actinobacillus suis is a common resident of the tonsils of the soft palate in pigs, but under certain circumstances it can invade, causing septicemia and related sequelae. Twenty-four putative adhesins are predicted in the A. suis genome, but to date, little is known about how they might participate in colonization or invasion. To better understand these processes, swine tonsil lysates were characterized by mass spectrometry. Fifty-nine extracellular matrix (ECM) proteins were identified, including small leucine-rich proteoglycans, integrins, and other cell surface receptors. Additionally, attachment of the wild type and 3 adhesin mutants to 5 ECM components was evaluated. Exponential cultures of wild-type A. suis adhered significantly more than stationary cultures to all ECM components studied except collagen I. During exponential growth, the A. suis Δflp1 mutant attached less to collagen IV while the ΔompA mutant attached less to all ECMs. The ΔcomE1 strain attached less to collagen IV, fibronectin, and vitronectin during exponential growth and exhibited differential attachment to collagen I over short adherence time points. These results suggest that Flp1, OmpA, and ComE1 are important during early stages of attachment to ECM components found in tonsils, which supports the notion that other adhesins have compensatory effects during later stages of attachment.
Topics: Actinobacillus suis; Adhesins, Bacterial; Animals; Bacterial Adhesion; Extracellular Matrix; Extracellular Matrix Proteins; Mass Spectrometry; Palate, Soft; Palatine Tonsil; Swine
PubMed: 27481253
DOI: 10.1128/IAI.00456-16