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Kerala Veterinary and Animal Sciences University, Wayanad

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20233
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Subject: Microbiology × End date: 2023 × Start date: 2023 ×
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    ThesisItemOpen Access
    ANTIBIOTIC RESISTANCE PROFILING OF BACTERIA ISOLATED FROM CORNEAL ULCERS IN DOGS
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2023-01-28) ASHTAMY M. G.; Dr. Binu K. Mani
    Corneal ulcers are one of the most frequent and painful ophthalmic conditions in dogs. Companion animals act as a source for transfer of AMR genes among bacteria between animals and humans. Antimicrobial resistance is a significant public health threat, which is mainly due to the indiscriminate use of antibiotics for a prolonged period of time. The present study deals with the isolation and identification of bacteria from corneal ulcers in dogs and their assessment of antibiotic resistance pattern by phenotypic and genotypic methods.The conjunctival swab samples collected from 15 dogs tested positive for corneal ulcers, were inoculated on to brain heart infusion agar and blood agar and incubated aerobically at 37 °C for 24 h. Out of the 15 samples, 18 isolates could be obtained with 12 as pure culture and three as mixed cultures, each with two types of colonies. The isolates were identified by their cultural characteristics on selective media, morphology, staining reactions and biochemical tests. The predominant isolates were Gram positive bacteria of the genera Staphylococcus (five), Corynebacterium (five) and Streptococcus (two). The rest of the six solates were Gram negative bacteria, viz. Pseudomonas aeruginosa (two), Klebsiella pneumoniae (two), Escherichia coli (one) and Neisseria spp. (one). Antibiotic susceptibility testing by disc diffusion method revealed that most of the isolates were resistant to quinolone group while only three of them were resistant to chloramphenicol. Polymerase chain reaction was performed to detect the genes,mecA, ermC, aac(6’)-aph(2”) and cat for resistance against methicillin, erythromycin, aminoglycoside and chloramphenicol, respectively and mutation in gyrA for resistance against quinolones, among the bacterial isolates. The mecAcould be detected in four, ermC in three and aac(6’)-aph(2”) in seven isolates.Out of seven isolates which amplified gyrA, the representative sample which was sequenced, revealed single point mutation. The mutation detected was silent, since it did not change any amino acid pattern. The cat gene could not be detected in any of the isolates.
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    ThesisItemOpen Access
    MOLECULAR DETECTION AND CHARACTERISATION OF CHICKEN ANAEMIA VIRUS FROM KERALA
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2023-01-28) VIDYA P.; Dr. Surya Sankar
    Chicken anaemia virus (CAV) is the aetiological agent of chicken infectious anaemia (CIA), an immunosuppressive disease which brings huge economic burden to poultry industry globally. Epidemiology of the disease and virulence of the circulating strains is to be known, while formulating prevention strategies to any infectious disease. So far, there are no reports regarding the presence of CAV among the poultry flocks in Kerala. In this scenario, the present is envisaged for the detection of CAV, employing polymerase chain reaction (PCR) using primers targeting the VP1, VP2 and VP3 genes of the virus, and its characterisation by nucleotide sequencing followed by phylogenetic analysis. Out of 100 pooled tissue samples collected from suspected cases, 29 were found to be positive for CAV by PCR. Isolation of virus from tissue homogenate of PCR-positive samples in embryonated chicken eggs through yolk ac route inoculation was carried out. Embryos were harvested 14 days post inoculation and PCR using same primers was carried out to confirm the presence of virus, but none of the samples turned positive. All the 29 samples were positive PCR targeting VP1 and VP3 gene. The representative amplicons from direct PCR targeting VP1, VP2 and VP3 genes were sequenced, analysed and compared with sequences in GenBank. The isolates from Kerala exhibited variations of about one per cent among each other and about two per cent variations were noted with other Indian isolates. Phylogenetic analysis based on VP1 gene revealed that samples clustered each other and also with isolates from different parts of India and with the vaccine strains, Del Ros, 26P4 and Cux-1. On amino acid analysis of the three genes, the profile of VP2 and VP3 is conserved in nature, while VP1 exhibited similarities with rapidly spreading and highly pathogenic strains of CAV. Histopathologic examination of thymus, bursa of Fabricius and bone marrow of PCR positive samples, lesions indicating apoptosis of thymic cortex, lymphocytic depletion in bursa of Fabricius and atrophy and aplasia involving all haematopoietic lineages of bone marrow were observed.
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    ThesisItemOpen Access
    ASSESSMENT OF IMMUNOGENIC POTENCY OF INACTIVATED VACCINE AGAINST RIEMERELLOSIS IN BREEDER DUCKS
    (COLLEGE OF VETERINARY AND ANIMALS SCIENCES MANNUTHY, THRISSUR , KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2023-02-09) LINA KUNJAMMA MATHEWS; Dr. Priya P. M.
    Riemerellosis or new duck disease, is an infectious disease in ducks caused by the bacterium Riemerella anatipestifer, which primarily causes an acute septicaemic infection in young ducklings. A subunit vaccine developed against the disease was compared to an inactivated vaccine in an earlier study, which proved the superiority of the latter in terms of efficacy. No studies have been carried out on maternally transferred antibodies (MTA) in ducklings born to the vaccinees. Hence, this study was undertaken. A total of 200 laying Kuttanad ducks of breeder stock maintained in the University Poultry and Duck Farm (UPDF), Mannuthy were grouped into two, comprising of 100 birds each, with T1 being the control group and T2, the treatment (vaccination) group. The oil-adjuvanted inactivated vaccine, prepared as per previously standardised protocol, was administered to T2group in two doses at weekly intervals. Blood samples, 20 each from T1 and T2, were collected on days 0, 14, 28, 56 and 90 post-immunisation (PI), whereas 10 eggs each from both the groups were collected on days 14, 28, 56 and 90 PI, to assess antibody titre in adult sera and egg yolk respectively, by ELISA. Fertile eggs collected between days 28 and 35 PI from each group were marked separately, incubated for hatching and the hatched-out day-old ducklings (n=24) from each group were selected randomly and reared. To evaluate MTA, blood was collected from six ducklings each from both the groups, on days 1, 3 and 10 to estimate antibody titre in the sera. The transfer of maternal antibodies was assessed by challenge studies upon inoculating 100 LD50 of RA1 subcutaneously to six ducklings each from both the groups on days 3 and 10. Statistical analysis of the ELISA titre of the adult duck sera revealed significant difference (p<0.001)between the titres of both the groups on all the days assessed except the 0th, confirming the potency of the vaccine in adult ducks. However, the assessment of MTA revealed some level of protective antibody in the ducklings in terms of mortality and gross pathological scoring, but not in levels detectable by ELISA.