Detection and characterization of Chlamydophila psittaci in asymptomatic feral pigeons (Columba livia domestica) in central Thailand

OBJECTIVE@#To detect and characterize Chlamydophila psittaci (C. psittaci) in asymptomatic feral pigeons in central Thailand.@*METHODS@#A total 814 swabs from the trachea and cloacae of 407 non-clinical feral pigeons in central Thailand were collected and tested for the presence of C. psittaci.@*RESULTS@#A 10.8% of feral pigeons in the sample group were positive as determined by nested PCR primer specific to C. psittaci. The outer membrane protein A (ompA) gene of positive samples exhibited amino acid identity of C. psittaci ranging from 71 to 100% and were grouped in genotype B. Exceptionally, BF1676-56 isolate was closely related to Chlamydia avium with 99% identification of the 16S ribosomal (r) RNA gene.@*CONCLUSIONS@#This is the first report on C. psittaci isolated from asymptomatic feral pigeons in Thailand, which provides knowledge for the disease status in pigeon populations in Thailand.

Detection and characterization ofChlamydophila psittaci in asymptomatic feral pigeons (Columba livia domestica) in central Thailand

Objective:To detect and characterizeChlamydophila psittaci(C. psittaci) in asymptomatic feral pigeons in centralThailand.Methods:A total814 swabs from the trachea and cloacae of407 non-clinical feral pigeons in centralThailand were collected and tested for the presence ofC. psittaci.Results:A10.8% of feral pigeons in the sample group were positive as determined by nestedPCR primer specific toC. psittaci.The outer membrane proteinA(ompA) gene of positive samples exhibited amino acid identity ofC. psittaci ranging from71 to100% and were grouped in genotypeB.Exceptionally,BF1676-56 isolate was closely related toChlamydia avium with 99% identification of the16S ribosomal(r)RNA gene.Conclusions:This is the first report onC. psittaci isolated from asymptomatic feral pigeons inThailand, which provides knowledge for the disease status in pigeon populations inThailand.

Detection and characterization of chlamydophila psittaci in asymptomatic feral pigeons (Columba livia domestica) in central Thailand

Objective: To detect and characterize Chlamydophila psittaci (C. psittaci) in asymptomatic feral pigeons in central Thailand. Methods: A total 814 swabs from the trachea and cloacae of 407 non-clinical feral pigeons in central Thailand were collected and tested for the presence of C. psittaci. Results: A 10.8% of feral pigeons in the sample group were positive as determined by nested PCR primer specific to C. psittaci. The outer membrane protein A (ompA) gene of positive samples exhibited amino acid identity of C. psittaci ranging from 71 to 100% and were grouped in genotype B. Exceptionally, BF1676-56 isolate was closely related to Chlamydia avium with 99% identification of the 16S ribosomal (r) RNA gene. Conclusions: This is the first report on C. psittaci isolated from asymptomatic feral pigeons in Thailand, which provides knowledge for the disease status in pigeon populations in Thailand.

Detection of the ompA gene of Chlamydophila pecorum in captive birds in Argentina / Detección del gen ompA de Chlamydophila pecorum en aves en cautiverio, en la Argentina

Bacteria belonging to the family Chlamydiaceae cause a broad spectrum of diseases in a wide range of hosts, Including humans, other mammals and birds. However, very little is known about chlamydial infections in birds in our region. In the present study, we examined 28 clinically normal birds In illegal captivity that were confiscated in the province of Córdoba, Argentina. The objective was to detect Chlamydophila spp. in cloacal swabs by genetic analysis of the ompA gene. Nested-PCR of the ompA gene identified five samples as Chlamydophila pecorum and the sequence analysis demonstrated the presence of the ompA gene of C. pecorum In these birds. On the other hand, Chlamydophila psittaci was not detected. These birds could be either asymptomatic reservoirs or subclinical carriers of C. pecorum. This is the first report of the detection of C. pecorum in Argentina.

Las bacterias que pertenecen a la familia Chlamydiaceae causan un extenso espectro de enfermedades en una amplia gama de huéspedes, incluidos los seres humanos, otros mamíferos y aves. Sin embargo, se sabe muy poco acerca de las infecciones por clamidias en aves de nuestra reglón. Esta Investigación examinó 28 aves clínicamente normales mantenidas en cautiverio ¡legal, que fueron confiscadas en Córdoba, Argentina. El objetivo fue detectar Chlamydophila spp. en hisopados cloacales por análisis del gen ompA. La PCR anidada del gen ompA reveló la presencia de Chlamydophila pecorum en cinco muestras. El análisis de secuencias demostró la presencia del gen ompA de C. pecorum en estas aves. Por el contrario, Chlamydophila psittaci no se detectó. Estas aves pueden ser reservónos asintomáticos o portadores subclínlcos de C. pecorum. Este es el primer informe de la detección de C. pecorum en la Argentina.

Clinico-pathological Features of Chlamydophila psittaci Infection in Parrots and Genetic Characterization of the Isolates / 대한수의학회지

Avian chlamydiosis is caused by Chlamydophila psittaci and considered as one of an important zoonotic disease throughout the world. Among more than 400 avian species including poultry and pet birds susceptible to the disease, psittacine birds were known to be mostly susceptible hosts. In Korea, no outbreak of the disease and genetic analysis of the agent in poultry and pet birds have been reported. With histopathological findings and genetic identification of a causative agent, avian chlamydiosis was identified in parrots submitted from the same pet bird farm in 2006 and 2009 for the diagnosis. Based on genetic sequences and phylogenetic analysis of ompA gene, the two isolates of Chlamydophila psittaci showed 100% of genetic similarity and belonged to genotype A, suggesting that the same agent might be continuously circulated in the farm. This result indicates that serological survey of the disease in pet bird farms and impact of the disease on significance in public health may be further studied.

Distribution of Salmonella paratyphi A ompA gene and immunological identification of the recombinant expressed product / 中华微生物学和免疫学杂志

Objective To construct a prokaryotic expression vector of Salmonella paratyphi A ompA gene, and to determine immunogenieity and immonuprotection of the recombinant expressed product rOmpA and carrying frequency of ompA gene in S. paratyphi A isolates. Methods ompA gene was amplified from a clinical S. paratyphi A strain JH01 by PCR, cloned into T-A cloning vector, and then the prokaryotic expression vector was constructed. The rOmpA expression was determined by SDS-PAGE. Antigenicity and immunoreactivity of rOmpA were determined by immunodiffusion test, Micro-Widal's test and Western blot assay, ompA gene exiting in 98 S. paratyphi A isolates was detected by PCR. By using immunoprotective effect of rOmpA against the challenge of S. paratyphi A strain 50001 in mice were determinded. Results Both the nucleotide and putative amino acid sequence identities of the cloned ompA gene were 100% com-pared to the reported corresponding sequences. The expression yield of rOmpA was approximately 65% of the total bacterial proteins, rOmpA was able to induce specific antibody in rabbits, and reacted efficiently with rabbit antisortm or the antiserum against whole cell of S. paratyphi A detected by Western blot. 94.9% (93/98) of the S. paratyphi A isolates had ompA gene. 41.7% (5/12) and 58.3% (7/12) of the mice im-murtized with 100 and 200 μg rOmpA were survival after lethal challenge with S. paratyphi A strain 50001. The titer of antibody to the H antigens of S. paratyphi spp in the sera from rOmpA immunized mice and sur-viral mice in the S. paratyphi A challenge detected by Micro-Widal's test was 1:5-1:40. Conclusion ompA gene has an extensive distribution in clinical isolates of S. paratyphi A. rOmpA possesses an immunogenicity and a certain immunoprotective effect, and can be used as the candidate antigen in genetic engineering vaccine.

Cloning and prokaryotic expression of the ompA gene of Chlamydia psittaci in cows / 中国人兽共患病学报

The ompA gene of Chlamyia psittaci in cows was amplified by PCR with primers designed based on those reported in GenBank.The amplified ompA gene was inserted into the bacterial plasmid vector pGEX-4T-1 and then transformed into E.coli BL21(DE3) with IPTG induction. The gene was derived from plasmid pMD18-T vector and then sequenced.It was demonstrated that this recombinant fusion protein of approximately 68kD in molecular mass was highly expressed in inclusion body and more pure proteins would be produced after purification.The fusion protein specifically reacted with positive sera of bovine Chlamydia as demonstrated by Western blotting. These results indicate that this recombinant fusion protein shows good reactivity and could be used to develop the diagnostic kit for bovine Chlamydia and genetic engineering vaccine.

Analysis of Leptospira interrogans ompA gene and immunological identification of its recombinant expression product / 中华微生物学和免疫学杂志

Objective To investigate the distribution of ompA gnne in 15 Chinese reference standard strains belonging to 15 serogroups of Leptospira interrogate, and to express recombinant OmpA ( rOmpA ) and to identify immunogenicity and immunoprotection of rOmpA. Methods Genomic DNAs from different leptospiral strains were extracted by phenol-chloroform method. Entire ompA gene fragments from the strains were amplified by PCR and then sequenced after T-A cloning. A prokaryotic expression system of ompA gene from L. interrogans strain 56601 was constructed, and the expression and yield of rOmpA were determined by SOS-PAGE plus Bio-Rad Agarose Image Analyser. Rabbits were immunized with rOmpA for obtaining antiserum, and immunodiffusion test was used to measure the antiserum's titer. Western blot assay was performed to determine the immunoreaetivity of rOmpA with the antiserum against rOmpA and antiserum against whole cell of L. interrogans strain 56601, while mi-croscopic agglutination test (MAT) was applied to detect the cross agglutination to the 15 L. interrogans strains. A leptospire adhering cell model and a leptospire infecting guinea pigs model were used to determine the adhesion-bloc-king effect of rOmpA antiserum and immunoprotection of rOmpA. Results All the 15 L. interrogans strains, but not L. biflexa strain Patoe Ⅰ , had sequence conserved ompA genes. The yield of rOmpA was approximate 20% of the total bacterial proteins, rOmpA could induce rabbits to produce antibody and immunodiffusion titer of the anti-serum was 1:4. Both antisera against rOmpA and against whole cell of L. interrogans strain 56601 were able to pro-duce positive Western blot signs to rOmpA, and the former offered 1 : 20-1 : 320 MAT titers to the 15 L. interrogans strains. 1: 10-1:160 dilutions of rOmpA antiserum could efficiently block L. interrogans strain 56601 adhering to J774A. 1 cells, and 100 μg and 200 μg rOmpA displayed 50.0% and 75.0% immunoprotective rates in the infee-ted guinea pigs. Conclusion ompA gene only exists in genomes of different pathogenic L. interrogans serogroups. rOmpA has relatively stronger antigenicity, cross immunoreactivity and certain immunoprotection, implying that this recombinant protein may be used as a candidate antigen for developing universal genetic engineering vaccine of L. interrogans.