Molecular and phenotypic characterization of shigatoxigenic Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) from piglets and infants associated with diarrhoea in Mizoram, India

Limited information is available on shiga toxin producing Escherichia coli (STEC) in pigs and infants from Aizawl, Mizoram and North Eastern region of India. This cross sectional study was conducted on faecal samples from pigs and infants to detect and characterize of STEC and enteropathogenic E. coli (EPEC). Serogrouping, molecular and phenotypic characterizations were done by standard molecular and cytotoxic assays. Out of 48 E. coli strains isolated from 320 diarrhoeic fecal samples of piglets, 44 belonged to 18 different serogroups, 3 (6.25%) were untypeable (UT) and 1(2.08%) was recorded as rough strain (R). Similarly, out of 17 E. coli strains isolated from 264 diarrhoeic fecal samples of infants, 16 belonged to O60 (94.1%) and 1(5.88%) was untypeable. Virulence genes (stx1, stx2, eaeA and hlyA) were detected by multiplex PCR assay. A total of 1260 E. coli were isolated from piglets (720) and infants (540) from 584 faecal samples. All together, 5.16% (65) E. coli isolates were found to be positive for at least one virulence gene (6.66% piglets and 3.15% infants). Out of the virulent gene positive E. coli 3.17% (32 from piglets and eight from infants) and 1.98% (16 from piglets and nine from infants) were recorded as STEC and EPEC, respectively. On the other hand, from the total 2.14% stx2 positive isolates, 16 and 11 were positive for stx2e and stx2c subtypes, respectively. Similarly, from the 4.04% eaeA positive isolates, 1.19% (15) were positive for bfpA gene, of which 1.67% (12) were piglets and 0.60% (3) were infants. All the isolates were exhibited varying degree of CPE on vero cell lines. In conclusion, STEC and EPEC seem to be associated with diarrhoea in piglets and infants in Mizoram. In piglets STEC strains represent as a major cause of diarrhoea while EPEC strains represent as major cause of diarrhoea in infants in North Eastern region of the India.Keywords: Enteropathogenic E. coli (EPEC), infants; piglets, shigatoxigenic E. coli (STEC), vero cell cytotoxicityAfrican Journal of Biotechnology, Vol 13(12), 1452-146

Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.7/July-2014/16.pdf RESEARCH ARTICLE Open Access

Evaluation of efficacy of saponin and freund's incomplete adjuvanted paratuberculosis vaccine in murine mode

Evaluation of efficacy of saponin and freund's incomplete adjuvanted paratuberculosis vaccine in murine model

Aim: To compare the efficacy between saponin adjuvanted paratuberculosis killed vaccine and Freund's incomplete (FIC) adjuvanted paratuberculosis vaccine in mice model. Materials and Methods: The study was conducted for a period of 11 months using 80 Swiss albino mice by dividing into four groups (Group I-mice vaccinated with killed Mycobacterium avium subspp. paratuberculosis (MAP) adjuvanted with saponin, Group II- for FIC, Group III- Saponin control and Gr IV- FIC control). Faecal shedding, changes in body weight, presence of local reactions and clinical symptoms, were evaluated. Serological assays for humoral and cell mediated immune response were determined by agar gel immunodiffusion (AGID) and nitric oxide test (NO) respectively. A total of 76 serum samples, 52 faecal samples and 20 tissue samples were collected at different intervals during the study period. ZN staining; AGID test and nitric oxide test were employed for analysis of samples. Results: A total of 38 samples (37 faecal and 1 tissue sample) and 18 serum samples were recorded as positive by ZN staining and AGID test respectively from all four groups of mice. Significant decrease in faecal shedding of organisms was observed in Group I mice vaccinated with saponin adjuvanted vaccine in comparison to Group II. Gain in body weight of Group I mice was recorded as higher than Group II. NO test revealed increase in the concentration of NO level in both vaccinated group but more significant in Group I. Conclusion: The tests results obtained revealed that killed MAP vaccine adjuvanted with saponin have higher protective efficacy in terms of reduced faecal shedding, gain in body weight, less side effects, absence of attributable specific symptoms of Johne's disease, etc. in comparison to killed MAP vaccine adjuvanted with FIC. The present study also reveals that AGID and NO estimation tests are specific tests which can be employed for diagnosis and comparison of efficacy of paratuberculosis vaccine

Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.7/Feb-2014/11.pdf RESEARCH ARTICLE Open Access

multocida isolated from pigs in Mizoram with special reference to progressive atrophic rhiniti