Isolation and characterization of Clostridium difficile from pet dogs in Assam, India.

One hundred and seventeen faecal samples from pet dogs (pup = 21 and adult = 96) brought for treatment to a veterinary clinic were examined for Clostridium difficile. A total of 16 (13.67%) samples were positive. Nine (56.25%) isolates were obtained from 17 adult dogs undergoing antibiotic treatment and this was significantly higher (p < 0.01) as compared to isolates from dogs without antibiotic treatment. Ten isolates (62.5%) were toxigenic (all toxinotype 0) and six were non-toxigenic. None of the isolates were positive for binary toxin genes. PCR ribotyping revealed three different ribotypes (012, 014 and 046) among A(+)B(+) isolates and five different ribotypes (010, SLO 131, and ACD 001 to ACD 003) among A(-)B(-) isolates. The PFGE analysis of toxigenic isolates revealed three different pulsotypes corresponding to the PCR ribotypes.

Enterotoxigenicity as an attribute of virulence in Yersinia enterocolitica.

Seven strains of Y. enterocolitica were screened for their enterotoxic activity. Three strains belonging to serogroups 0:3 and 0:9 elicited enterotoxic response in rabbit ligated gut segments and in infant mice. The enterotoxin resisted heat at 65 degrees and 100 degrees C for 20 min. The toxin was eluted in the second beak material during Sephadex G-75 gel filtration. On the basis of polyacrylamide disc gel electrophoresis the toxic component had a molecular weight of about 12,400.

Effect of conventional and controlled freezing method on the post thaw characteristics of boar spermatozoa.

The objective of the present study was to evaluate the effectiveness of conventional, and controlled freezing method adopting three freezing rates 20°C, 40°C and 60°C/min for cryopreservation of boar semen. Sixty sperm-rich fractions of ejaculates from six boars were utilized for freezing of semen with different freezing methods in lactose-egg yolk glycerol extender using 0.5 ml straws. Semen samples were evaluated for sperm motility, live sperm, acrosome integrity, plasma membrane integrity (PMI) by carboxyfluorescein diacetate plus propidium iodide (PI) staining, mitochondrial membrane potential (MMP) by combined JC-1 plus PI staining and lipid peroxidation (LPO) by BODIPY (581/591)-C11 probe after equilibration and after freezing. The results revealed that the post thaw sperm motility, live sperm, live intact acrosome and plasma membrane integrity were significantly (p<0.05) higher in all the three controlled freezing methods (20°C, 40°C and 60°C/min) as compared to that in conventional method. In addition, the controlled freezing methods yielded higher (p>0.05) mean values of live sperm with high MMP as compared to conventional freezing. However, the post thaw sperm LPO did not influence by difference in freezing methods. No significant difference on the post thaw sperm qualities was recorded among the three controlled freezing rates. All the sperm parameters assessed declined significantly (p<0.05) after freezing as compared to that after equilibration irrespective of freezing method employed. In conclusion, cryopreservation of boar semen with controlled freezing methods conferred better post thaw sperm quality as compared to conventional method, and the freezing rates of either 20, 40 or 60°C/min could provide better freezability of boar semen.