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1975 - 197941980 - 19882
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Subject: Veterinary Microbiology × Author: KAU × End date: 1989 × Type: Thesis × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    Characterization of staphylococci isolated from cases of mastitis and study of their R plasmids
    (Department of microbiology, College of veterinary and animal sciences, Mannuthy, 1986) Mathew, E S; KAU; Punnoose, K T
    The emergence of drug resistant staphylococci causing mastitis deserve serious investigation. The work was intended to characterize staphylococci isolated from cases of bovine mastitis and to study their R plasmid transfer in vitro. The characterization was done using glucose and mannitol fermentation, catalase production, coagulase production, Iysostaphin sensitivity and bacteriophage typing. The antibiogram of the isolates was done by agar diffusion method using 14 chemotherapeutic agents (amoxicillin, ampicillin, bacitracin, chloramphenicol, cloxacillin, erythromycin, gentamicin, methicillin, neomycin, nitrofurantoin, penicillin, streptomycin, sulphamethoxazole and tetracycline) and by agar dilution method using eight antibiotics (ampicillin, chloramphenicol, rifampicin, streptomycin, tetracycline , gentamicin, erythromycin and penicillin) The in vitro transfer of R plasmids was tried using selected S.aureus and coagulase-negative staphylococcal isolates as donors and S.aureus RN 450RF and S.epifermidis 131S as recipients. From 360 milk samples collected from cases of bovine mastitis 17 strains of S.aureus and 35 strains of coagulase negative staphylococci were isolated. Lysostaphin sensitivity test was positive for 90.38% of the isolates, but this could not be used to differentiate between coagulase positive and negative staphylococci. The results of phage typing revealed a predominance of group III phages over the other groups and the possible role of human strains of staphylococci in producing mastitis in animals. None of the strains were resistant to mercuric chloride. From the antibiogram rifampicin , bacitracin, neomycin , methicillin, gentamicin, cloxacillin, nitrofurantoin and chloramphenicol were found to be the drugs of choice in the treatment of bovine mastitis caused by staphylococci. When S. aureus Rn 450RF was used as recipient six of the ten selected S.aureus isolates could transfer either one or more drug resistance markers and the mode of transfer was suspected to be by conjugation. All the four selected streptomycin resistant coagulase –negative staphylococcal donors were found to transfer the R plasmid DNA to the recipient., S.aureus RN 450RF, which was established to be through conjugation. The drug resistant S. aureus as well as coagulase negative staphylococcal strains failed t transfer their resistance to S.epidermidis 131S.
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    ThesisItemOpen Access
    Characterization and immunology of inflenza virus type a isolated from duck in Kerala
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1988) Mini, M; KAU; Sulochana, S
    Ducks are generally regarded as resistant to influenza virus infection. During the early halves of 1985 and 1987 influenza A viruses were isolated from cases of respiratory disease causing 15 to 20 percent mortality in two to six week-old ducklings at Government Duck Farm, Niranam. Four strains of the virus (A/duck/India /1/85 (H9N2)-CDN, A/duck/India /2/87 (H3N?) –DT3; A/duck/India /7/87 (H3N2)-T19 and A/duck/India /14/87 (H9N?-lgl isolated from these out breaks were studied in detail with particular reference to their characteristics, Pathogenicity and immunogenicity. The strains were propagated in nine day embryonated chicken eggs by allantoic route of inoculation. All the four strains multiplied well killing the embryos in two to four days time. Though characteristic lesions were not present, the embryos were slightly congested. The chorioallantoic membranes showed moderate congestion and oedema but no pock lesions. Infectivity titers were 108.5 EID 50/0.2ml; 108.25 EID 50/0.2ml 105.75 EID 50/0.2ml and 108.5 EID 50/0.2ml respectively for CDN, DT3, T19 and lgl. The corresponding HA titres were 1:64 , 1:128, 1:64 and 1:256 The strains also multiplied well in duck embryos but no specific lesions were seen either in the embryo or on the chorioallantoic membranes. The infectivity titers were low compared to the titers obtained in chick embryos. All the strains were inactivated at 560C in 30 minutes. They lost their infectivity at PH 3.2 while HA property was not considerably reduced except for lgl. At PH 7.2 both infectivity and HA property were not affected. But infectivity was slightly affected and HA property was markedly reduced at PH 9.0. The viruses were chloroform sensitive and agglutinated red cells from cattle, sheep, goat, guinea pigs, horse, rabbit, rat mouse, chicken and man (0, A and B Groups). Chicken embryo fibroblastic infected with strain CDN produced cytopathic effects characterized by rounding of cells affecting the whole monolayer in 96 hours. The remaining three strains did not produce any CPE. In all the four cases virus infection was evidenced as the cell culture fluid gave haemagglutination. The infectivity titers of these fluids were 106.5 EID 50/0.2ml and 105.5 EID 50/0.2 ml 104.0 EID 50/0.2 ml and 105.5 EID 50/0.2 ml respectively for CDN, DT3, T19 and lgl. Two common antigens possibly the type specific MP and NP antigens were detected in the CAM extracts of embryos infected with these strains by agar gel precipitation and immunoelectrophoresis. Mean death time for these strains calculated according to the method adopted for NDV were 78 hours, 76.8 hours, 72 hours and 76 hours respectively for CDN, DT3, T19 and lgl, while the ICPI in day-old chicks were 0.325, 0.66, 0.00 and 0.16 and IVPI 0.00 in all cases. Pathogenicity and immunogenicity studies were carried out in day-old, one week-old and two week-old ducklings with strain CDN and in the week-old ducklings with strain lgl. Strain CDN produced hundred percent mortality in day old ducklings that received the virus by oral , occulonasal and subcutaneous routes. They died with no marked clinical signs except droopiness, discharges from the eyes. Slight diarhoea and ruffled feathers in some of them. The pathogenicity indices were 1.19, 1.15 and 1.51 respectively for group A,B and C. The ducklings that were kept to study contact infection revealed cloacal excretion of the virus till 12th day, through tracheal excretion stopped by 10th day. None of the birds in all the four groups that survived seven day of infection did reveal any specific seven day of infection did reveal any specific HI antibodies. In one week-old ducklings no clinical symptoms were observed. Virus could be isolated from cloacal and throat swabs before death and from tissues of dead birds. The pathogenicity indices were 0.36, 0.00 and 0.20 respectively for group A, B and C. In contact ducklings picked up infection as indicated from virus isolation and antibody titration. Both infected and incontact birds showed HI antibodies from 7th day onwards. By 14th day the titres reached peak level ranging between of 1:16 to 1:64 followed by a decline and remained steady through out the observation period. The two week-old ducklings did not show any clinical symptoms or death. But they revealed tracheal and cloacal shedding of the virus. The HI antibody titres never increased beyond 1:16. None of the incontent birds either showed clinical symptoms or death. Positive virus isolation could be made till the 7th day. Antibody response was also very poor and HI antibody titers never increased beyond 1:4. One week-old ducklings infected with strain lgl remained apparently healthy throughout the period of observation. However, virus isolations were made from cloacal and tracheal samples from 3rd to 7th day. In birds that received the virus by oral route, HI antibody titres were 1:4, 1:8 and 1:4 respectively on 7th, 14th and 21st day and nil by 28th day. In order two groups the birds did not reveal HI antibodies till 28th day. None of the incontact birds in all three groups showed clinical symptoms, death or any other indication of infection by the virus. In addition the sera from these birds were also negative for HI antibodies.
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    ThesisItemOpen Access
    Studies on the bacterial species associated with gastroenteritis in goats
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1979) Sebastian, Joseph; KAU; Abdulla, P K
    The information regarding the incidence, etiology and pathogenicity of enteric pathogens in goats is very meagre in our country. The present study is aimed at the isolation, identification and characterisation of Enterobacterial organisms from cases of enteritis in goats. The study also included, determination of sensitivity pattern of the isolates to various chemotherapeutic agents. A total of 190 specimens, which included rectal swabs (60), intestinal contents, portions of large and small intestines (92) and mesenteric lymph nodes (38) collected from live/dead animals were examined for enteric pathogens. From these specimens examined, 86 isolates of Escherichia coli (45.26 per cent), 39 Enterobacter cloacae (20.33 per cent) and two Salmonella (1.05 per cent) were obtained. Of all the E.coli isolates, only one (EC/11) was found to be haemolytic. In addition to the above specimens, eight samples of heart blood and 34 specimens of lung tissues collected from cases of gastroenteritis were also examined for the presence of bacterial organisms. Seven isolates of Streptococcus pyogenes (from lung tissues only), 15 isolates of Klebsiella Pneumoniae (from lung tissues only), and one isolate of Corynebacterium pyogenes (from lung tissues only) were obtained. The ability of haemolytic E.coli (EC/11) to produce necrotoxin on rabbit skin was tested and the lesions produced were of necrotic changes. The strain was also found to be pathogenic to mice when tested. One isolate of Salmonella (S/1) was also tested for its pathogenicity to mice, and found non – pathogenic. Enterotoxin production in rabbit ileal loop was studied with haemolytic (EC/11) and non – haemolytic (EC/15) E.coli. The test materials included peptone water culture, soft agar culture fluid and acetone precipitated culture fluid. The results of the experiment have shown that, non – haemolytic E.coli produced dilatation reaction, while the haemolytic E.coli did not. The lesions noticed in the ileal segments of positive reaction were typical of enteritis. Antibiotic sensitivity studies were conducted using 11 chemotherapeutic agents (Ampicillin, bacitracin, chloramphenicol, erythromycin, gentamicin, kanamycin, nitrofuran, penicillin, streptomycin, sulphonamide and tetracycline) on E.coli Salmonella and Enterobacter cloacae. The result showed that cent per cent isolates of E.coli were sensitive to gentamicin, 95.35 per cent to nitrofuran, 88.37 per cent to chloramphenicol, 60.47 per cent to kanamycin, 40.70 per cent to streptomycin, 8.14 per cent to tetracycline and 2.33 per cent to erythromycin. All the 39 isolates of Enterobacter closcae tested were sensitive to gentamicin and kanamycin, whereas 30 (76.92 per cent) were sensitive to chloramphenicol and nitrofuran and 15 (38.46 per cent) to streptomycin. The drugs of choice for Salmonella were found to be gentamicin, chloramphenicol, nitrofuran and streptomycin.
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    ThesisItemOpen Access
    Immunology survey on the incidence of infectious bronchitis(IB) and infectious laryngotracheitis (ILT) in poultry in and around Trichur
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1979) George, M C; KAU; Punnoose, K T
    Infectious bronchitis and infectious laryngotrancheitis are the two viral diseases of poultry responsible for economic loss to the poultry industry by way of decreased egg production, poor quality of eggs, decreased feed efficiency and loss of weight gain. These disease have been reported from the neighbouring states of Kerala. In the present study a serological survey was carried out to understand the prevalence of these two disease in the poultry population in and around Trichur. A total of 2,110 serum samples have been collected from the field, comprising of white leghorn, Rhode Island Red and Desi birds belonging to different age groups. Serum samples were collected from organized farms, from birds kept by farmers and from the birds slaughtered in different hotels at Trichur. These serum samples were tested against the infectious bronchitis and infectious laryngotracheitis by employing agar gel precipitation test. The chorioallantoic membrane and allantoic fluid of infected embryos were used for the preparation of antigens for agar gel precipitation test. The potency of antigens was tested by conducting the agar gel precipitation test with corresponding hyper immuns sera prepared in white leghon male chicks of six to eight weeks of age. A line of precipitation was obtained in both cases which was close and curved towards the antigen well, because of the high concentration of antibody in the sera and due to the high molecular weight of the antigen. In the case of infectious bronchitis the line of precipitation was distinct where as in case of infectious laryngotrachetis it was diffused. The antigen, whose efficiency was tested using hyper immune sera, was used to test samples of sera collected from the field. The samples were pooled to 211 groups and tested for the presence of infectious bronchitis and infectious larygotracheitis precipitating antibodies separately by agar gel precipitation test. None of the samples gave precipitin line either to infectious bronchitis or to infectious larygotracheitis. So it was assumed that both of these viral disease are not prevalent in Trichur and its suburbs.
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    ThesisItemOpen Access
    Investigation on the aetiology of plague -like disease in ducks In Kerala
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1978) Krishnan Nair, G; KAU; Sulochana, S
    An investigation was carried out to isolate, characterize and identify the agent responsible for the outbreak of duck plague – like disease in ducks in Kerala. Specimens (liver and spleen) from field cases, were processed for virus isolation and were inoculated into either developing duck or chick embryos, by chorio – allantoic (C.A.M.) or allantoic cavity method. Virus isolation was possible only by C. A. M. inoculation of duck embryos and was confirmed by inoculation of the C.A.M. extracts into duck embryo fibroblast (D.E.F.) cell cultures. The cytopathic changes produced by the field isolate DPV – N; its physico – chemical characteristics such as sensitivity to chloroform and 5 – iodo – 2 deoxyuridine; and the effect of exposure to various pH values such as 4.7, 7.2 and 9.1, were compared with that of a known duck plague virus DPV – K, received from the Veterinary Biological Institute, Mannuthy. In D.E.F. cell cultures, the cytopathic changes produced by DPV – N and DPV – K were rounding and clumping of cells, with characteristic basophilia and granulation of the cytoplasm. Although the initial titers of both DPV - N and DPV - K were only 105 and 106.25, they increased to 107.5 and 108.25 respectively, on further passages. The field isolate DPV – N and the known duck plague virus DPV – K were sensitive to 5% chloroform, with complete inactivation in ten minutes. Similarly, both the strains failed to multiply and produce cytopathis changes in cells treated with IUdR, at the rate of 100 micrograms per ml. However, differences were observed in their thermostability and pH sensitivity. Although DPV – K was inactivated completely at 560 C. in 30 minutes, DPV – N was only partially reduced in titer. DPV – N was also found to be resistant, when both the strains were exposed to pH 4.7, for a period of four hours at room temperature. But both were unaffected at pH 7.2 and got inactivated at pH 9.1. Both the strains also failed to produce any haemagglutination reaction with chicken R.B.C or precipitation reaction in agar gels. Although duck plague specific antiserum neutralized homologous strain DPV – K and the newly isolated strain DPV – N, the serum titers obtained with the latter was only less. Experimental infection studies have shown that one to six week – old ducklings were equally susceptible to DPV – N and DPV- K, either with the spleen extract or with tissue culture passaged sample. The symptoms and lesions produced in both cases, were similar to those described for duck plague and also to those seen during the disease outbreak in Kerala. The virus that caused an outbreak of duck plague - like disease in Kerala is found to be indistinguishable from that of duck plague. It is also strongly felt that the lack of complete protection of birds vaccinated with duck plague vaccine is due to t possible strain variation between the classical duck plague virus DPV – K and the virus as it occurred during this outbreak. However, it needs thorough in vitro cross neutralization and in vivo cross protection tests before any definite conclusions can be made on the strain variation of duck plague virus.
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    ThesisItemOpen Access
    Studies on the bacterial species associated with digestive disturbance in pigs
    (Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1975) Balakrishna Pillai, K P; KAU; Abdulla, P K
    Prior to this investigation, limited studies conducted in the department of Bacteriology, College of Veterinary and Animal Sciences, Mannuthy, have revealed the association of pathogenic strains of E. coli and Salmonella with enteric disorders of pigs. Therefore, a detailed study of the incidence and magnitude of prevalence of those pathogens was carried out. A total of 274 specimens collected from sick as well as dead animals were examined. Faecal materials collected from living as well as dead animals, mesentric lymphnode, spleen, liver, lungs and heart blood formed the materials for isolation studies. Both enrichment and selective media like selenite and tetrathionate broth, D. H. S. broth and D.H.S. agar, modified MacConkey medium 1 & 11, and composite medium 1 & 11 were employed for isolation of pathogens. A total of 75 strains of E. coli and 24 strains of Salmonella were isolated and studied. Most of the isolations were made from piglings ages 3 – 8 weeks. Out of 75 strains of E. coli only 5 strains were found pathogenic based on various tests like haemolysin, necrotoxin and enterotoxin production and pathogenicity to mice. These isolates belonged to serogroup 05, 017 and 039. Salmonella strains belonged to two serotypes, S. weltevreden and S. typhimurium var coCopenhagen The identity of the isolates were confirmed biochemically and serologically. Pathogenicity studies conducted with two strains of Salmonella weltevreden and Salmonella typhimurium Var Copenhagen have revealed that they were pathogenic to laboratory animals like mice, guinea pigs and rabbits. It has also been observed that these serotypes could produce enteric form of the disease in primary hosts. Invitro drugsensitivity studies were carried out to determine the effectiveness of antibiotic to gastrointestinal disorders the effectiveness of antibiotic to gastrointestinal disorders caused by these species. It has been observed that all E. coli and Salmonella strains tested were sensitive to chloramphenicol. However multiple resistance was observed to penicillin, streptomycin, tetracycline, erythromycin and nitrofurantoin. The significance, possible role of infection by these species and their drug sensitivity reactions are discussed.