Pathogenicity Of Pasteurella Multocida Serotypes A:3, D:1 And D:3 In Rabbits

Eighty-two isolates of P. multocida were recovered from healthy and diseased rabbits in a rabbitry at Universiti Putra Malaysia. S ixty three isolates were obtained from adult rabbits and 1 9 isolates were from juvenile rabbits. Bacterial identification by biochemical tests, capsular and somatic serotyping and sensitivity to the antimicrobials were conducted. Capsular typing revealed that the major capsular type was type A (89%), while type D was less frequent ( 1 1 %). Somatic serotyping of 46 isolates showed that serotypes 1 and 3 were more frequent among the capsular types. Most isolates were sensitive to several common antimicrobials but some were resistant to neomycin, penicillin, cloxacillin and tetracycline. Six of 40 isolates of P. multocida from healthy ( 1 8 isolates) and diseased (22 isolates) rabbits were found to harbour plasmids. There was no correlation between presence of plasmids and serotype, resistance to antimicrobial agents and from the site which the bacteria were cultured. Random amplification polymorphic DNA (RAPD) was applied to subtype 40 P. multocida isolates using two single primers to test their abilities to generate individual fingerprints. A wide heterogeneity within the isolates was observed. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of the 40 isolates revealed over 40 protein bands with high molecular weight bands indicating striking homogeneity among the isolates. Twenty-two different patterns were observed

Molecular characterization of Pasteurella multocida isolates from rabbits

Forty isolates of Pasteurella multocida from healthy (17 isolates) and diseased (23 isolates) rabbits were assayed for the presence of plasmids in seeking to determine whether any correlation exists between the presence of plasmids and health status, sensitivity to antimicrobial agents, capsular and somatic type, and the anatomic site of isolation. Six isolates were found harboring plasmids. A similar ladder pattern ranging from 18 to 3 megadalton (Mda) were found in three isolates recovered from diseased rabbits. One band of molecular weight 6.6 Mda was shared by four of five (4/5) isolates from the diseased rabbits. No correlation was found between the presence of the common plasmids and serotype, resistance to antimicrobial agents, and anatomic sites from which the bacteria were cultured. Random amplification polymorphic DNA was applied to subtype all the isolates of P. multocida. Two single primers were tested for their abilities to generate individual fingerprints by using PCR. Primer 1 grouped the isolates into 7 profiles, and primer 2 grouped them into 15. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) results show the presence of a wide heterogeneity within P. multocida isolates. Therefore RAPD-PCR is an efficient technique to detect the DNA polymorphism and could be used to discriminate P. multocida of rabbit isolates together with serologic typing

Effect of Corticosteroids and Neuropeptides on the Expression of Defensins in Bovine Tracheal Epithelial Cells

Susceptibility to bacterial pneumonia in cattle is enhanced by stressors such as transportation, weaning, and commingling, which trigger a physiologic stress response resulting in elevated levels of endogenous corticosteroids and catecholamines. To determine the effect of neuroendocrine mediators on the expression of innate defense peptides in the lung, bovine tracheal epithelial cells were exposed to dexamethasone, catecholamines, acetylcholine, or substance P, and then β-defensin expression was quantified using real-time reverse transcription-PCR. Basal expression of tracheal antimicrobial peptide (TAP) mRNA was not affected by any of the mediators tested. However, induction of TAP expression by lipopolysaccharide was significantly inhibited by pretreatment with dexamethasone. Bronchial biopsy specimens from dexamethasone-treated calves had significantly lower expression of TAP and lingual antimicrobial peptide (LAP) mRNA than saline-treated controls following 48 h of treatment. Lipopolysaccharide-elicited neutrophil recruitment was enhanced in the lungs of dexamethasone-treated calves compared to saline-treated controls. These findings indicate that modulation of epithelial antimicrobial peptide expression is one mechanism through which corticosteroids and stress may impair innate pulmonary defenses

Genotypic and phenotypic relationship in Burkholderia pseudomallei indicates colonization with closely related isolates

Seven isolates of Burkholderia pseudomallei from cases of melioidosis in human (2 isolates) and animal (2 isolates), cat (one isolate) and from soil samples (2 isolates) were examined for in vitro sensitivity to 14 antimicrobial agents and for presence of plasmid DNA. Randomly amplified polymorphic DNA (RAPD) analysis was used to type the isolates, using two arbitrary primers. All isolates were sensitive to chloramphenicol, kanamycin, carbenicillin, rifampicin, enrofloxacin, tetracycline and sulfamethoxazole-trimethoprim. No plasmid was detected in all the isolates tested. RADP fingerprinting demonstrated genomic relationship between isolates, which provides an effective method to study the epidemiology of the isolates examined

Genotypic and phenotypic relationship in Burkholderia pseudomallei indicates colonization with closely related isolates

Seven isolates of Burkholderia pseudomallei from cases of melioidosis in human (2 isolates) and animal (2 isolates),cat (one isolate) and from soil samples (2 isolates) were examined for invitro sensitivity to l4 antimicrobial agents and for presence of plasmid DNA. Randomly amplified polymorphic DNA (RAPD) analysis was used to type the isolates, using two arbitrary primers. All isolates were sensitive to chloramphenicol, kanamycin, carbenicillin, rifampicin, enrofloxacin, tetracycline and sulfamethoxazole trimethoprim. No plasmid was detected in all the isolates tested. RADP fingerprinting demonstrated genomic relationship between isolates, which provides an effective method to study the epidemiology of the isolates examined

Opinion on Not Terminating Control Animals in the Recovery Phase of Non-rodent Toxicology Studies

Nonclinical toxicology studies required to support human clinical trials of new drug candidates are generally conducted in a rodent and a non-rodent species. These studies typically contain a vehicle control group and low, intermediate, and high dose test article treatment groups. In addition, a dosing-free recovery phase is sometimes included in toxicity studies to demonstrate reversibility of toxicities observed during the dosing phase and may include additional animals in the vehicle control and one or more dose groups. Typically, reversibility is determined by comparing the test article-related changes in the dosing phase animals to concurrent recovery phase animals at the same dose level. Therefore, for interpretation of reversibility, it is not always essential to terminate the recovery vehicle control animals. In the absence of recovery vehicle control tissues, the pathologist’s experience, historical control database, digital or glass slide repositories, or literature can be used to interpret the findings in the context of background pathology of the species/strain/age. Therefore, in most studies, the default approach could be not to terminate recovery vehicle control animals. This manuscript provides opinions on scenarios that may or may not necessitate termination of recovery phase vehicle control animals in nonclinical toxicology studies involving dogs and nonhuman primates

Frequencies of liver abnormalities in HCV infected mice.

<p>Frequencies of liver abnormalities in HCV infected mice.</p

Hepatitis C virus mediated chronic inflammation and tumorigenesis in the humanised immune system and liver mouse model

<div><p>Hepatitis C is a liver disease caused by infection of the Hepatitis C virus (HCV). Many individuals infected by the virus are unable to resolve the viral infection and develop chronic hepatitis, which can lead to formation of liver cirrhosis and cancer. To understand better how initial HCV infections progress to chronic liver diseases, we characterised the long term pathogenic effects of HCV infections with the use of a humanised mouse model (HIL mice) we have previously established. Although HCV RNA could be detected in infected mice up to 9 weeks post infection, HCV infected mice developed increased incidences of liver fibrosis, granulomatous inflammation and tumour formation in the form of hepatocellular adenomas or hepatocellular carcinomas by 28 weeks post infection compared to uninfected mice. We also demonstrated that chronic liver inflammation in HCV infected mice was mediated by the human immune system, particularly by monocytes/macrophages and T cells which exhibited exhaustion phenotypes. In conclusion, HIL mice can recapitulate some of the clinical symptoms such as chronic inflammation, immune cell exhaustion and tumorigenesis seen in HCV patients. Our findings also suggest that persistence of HCV-associated liver disease appear to require initial infections of HCV and immune responses but not long term HCV viraemia.</p></div