Isolation and characterization of chlamydia psittaci with emphasis on protein profile

Abstract

For isolation of Chlamydia psittaci 46 clinical cases associated with abortions in livestock from livestock farms and Veterinary hospitals in and around Thrissur were screened. Impression smear staining of the clinical materials USin9 Giemsa, Modified Ziehl Neelsen and Gimenez revealed two positive cases. Both were from aborted foetuses, one from bovine (M-121) and the other from caprine (M-430). Chick embryo inoculation by YS route was used for isolation of the organism. The organisms could be isolated only from the two cases positive by preliminary screening, as confirmed by staining of YS impression smears. The mortality rate in CE was more in case of M-430 compared to the other two isolates (M-121 and reference isolate, P-156). All the three isolates produced patchy haemorrhagic lesions in YS and skin of embryoS. An overall isolation percentage of 4.3 was obtained in this study. All the three isolates were resistant to sodium sulphadiazine. Pathogenicity studies indicated that, all the three isolates were of moderate virulence for mice and guinea pigs. Based on AGPT, the local isolates were confirmed as Chlamydia psittaci. All the three isolates caused rounding and swelling of fibroblast cells and syncytia formation at 24h PI in Mc Coy cell line. By 48 to 72 h PI, these effects became more prominent with detachment of cells from adjacent cells and from the glass surface. Purified EBs were prepared from infected Mc Coy cell line by Urografin gradient centrifugation. After confirming the presence of sufficient amount of protein by Biuret method, they were used for SDS-PAGE. A total of 12 polypeptide bands were obtained for both the bovine isolates while the caprine isolate gave 10 bands. Molecular weights of 148 kDa and 135 kDa were present only in P-156 and 152 kDa and 137 kDa were unique for M-121. Bands at 152 kDa, 148 kDa, 137 kDa, 135 kDa, 32 kDa, 18 kDa, 15 kDa and 7 kDa were lacking in M-430. This isolate was having unique bands of 155 kDa, 19 kDa, 12.2 kDa and 6.4 kDa.