ABSTRACT
OBJECTIVE: To detect and characterize the full range of chlamydial infections in cats with ocular disease by use of polymerase chain reaction (PCR) assays, cytologic examination, immunohistochemical analysis, and evaluation of clinical information including status for feline herpesvirus-1 (FeHV-1). SAMPLE POPULATION: DNA extracted from 226 conjunctival samples obtained from cats with clinically diagnosed keratitis or conjunctivitis and 30 conjunctival samples from healthy cats. PROCEDURE: PCR assays for the 16S rRNA gene specific for the order Chlamydiales and a new Chlamydophila felis (formerly Chlamydia psittaci) species-specific 23S rRNA gene were performed. Seventy-four conjunctival samples were prepared with Romanowsky-type stain, grouped on the basis of inflammatory pattern, and screened for chlamydial inclusions by use of immunohistochemical analysis. Clinical information and FeHV-1 status were recorded. RESULTS: 26 (12%) specimens had positive results for the only known feline chlamydial pathogen, C felis. Surprisingly, an additional 88 (39%) were positive for non-C felis chlamydial DNA. Identification of non-C felis chlamydial DNA by direct sequencing revealed 16S rRNA gene sequences that were 99% homologous to the sequence for Neochlamydia hartmannellae, an amebic endosymbiont. Chlamydial prevalence was significantly higher in cats with ocular disease. CONCLUSIONS AND CLINICAL RELEVANCE: Application of a broad-range detection method resulted in identification of a new agent associated with ocular disease in cats. Finding chlamydia-like agents such as N hartmannellae in coinfections with their obligate amebic host, Hartmannella vermiformis, raises questions about the potential role of these microorganisms in causation or exacerbation of ocular disease in cats.
Subject(s)
Cat Diseases/diagnosis , Chlamydia Infections/veterinary , Chlamydia/isolation & purification , Conjunctivitis, Inclusion/veterinary , Animals , Base Sequence , Cat Diseases/microbiology , Cat Diseases/pathology , Cats , Chlamydia/classification , Chlamydia/genetics , Chlamydia Infections/diagnosis , Chlamydia Infections/pathology , Conjunctivitis, Inclusion/diagnosis , Conjunctivitis, Inclusion/pathology , Molecular Sequence Data , Polymerase Chain Reaction , RNA, Bacterial/genetics , RNA, Bacterial/isolation & purification , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 16S/isolation & purification , RNA, Ribosomal, 23S/genetics , RNA, Ribosomal, 23S/isolation & purification , Sequence Alignment , Sequence Homology, Nucleic AcidABSTRACT
The objective of this study was to determine whether a chlamydial strain recovered from growing and finishing swine with conjunctivitis or keratoconjunctivitis could cause the same infections in gnotobiotic pigs. The strain shares biological characteristics with Chlamydia trachomatis. After propagation in Vero cells and preparation of the inoculum (10(7) inclusion-forming units/ml), chlamydial strain H7 was instilled into the ventral conjunctival sac (0.15 ml/sac) of 12 anesthetized 3-day-old gnotobiotic piglets. Four age-matched gnotobiotic piglets were anesthetized and sham infected with uninfected cell culture lysates. None of the principal piglets developed clinical symptoms of conjunctivitis or keratoconjunctivitis. Principal piglets necropsied 7 days postinfection (DPI) had histologic lesions of mild or moderate conjunctivitis; immunohistochemical evaluation revealed chlamydial antigen in conjunctival epithelium. A majority of principal piglets necropsied at 14-28 DPI had histologic lesions of mild conjunctivitis, but chlamydial antigen was not detected by immunohistochemistry. The results indicated that chlamydial strain H7 can cause mild or occasionally moderate conjunctivitis in gnotobiotic pigs, but the conjunctival infection is asymptomatic.
Subject(s)
Chlamydia trachomatis , Conjunctivitis, Inclusion/veterinary , Germ-Free Life , Swine Diseases/microbiology , Animals , Chlamydia trachomatis/isolation & purification , Conjunctiva/microbiology , Conjunctiva/pathology , Conjunctivitis, Inclusion/pathology , Conjunctivitis, Inclusion/physiopathology , Swine , Swine Diseases/pathology , Swine Diseases/physiopathologyABSTRACT
Monoclonal antibodies to a strain of Chlamydia psittaci isolated from guinea pig inclusion conjunctivitis (GPIC) were developed. Only five of the 15 hybridomas isolated produced antibodies specific for the GPIC strain, while seven others produced antibodies which cross reacted with other strains and another species. Strain-specific and species-specific monoclonal antibodies were isotyped as IgG2a and IgG3, respectively. It appears that the GPIC strain has at least two epitopes, one of which is specific for the strain and the other common to the species. These monoclonal reagents may be used to immunotype GPIC agents, better than available methods and may be of potential use in the development of vaccines against chlamydial infections.
Subject(s)
Antibodies, Monoclonal/biosynthesis , Chlamydophila psittaci/immunology , Conjunctivitis, Inclusion/veterinary , Guinea Pigs , Rodent Diseases/microbiology , Animals , Antibodies, Bacterial/biosynthesis , Antibodies, Bacterial/immunology , Antibodies, Monoclonal/immunology , Antibody Specificity , Conjunctivitis, Inclusion/microbiology , Cross Reactions , Female , Hybridomas , Immunoenzyme Techniques , Immunohistochemistry , Mice , Microscopy, Electron , Species SpecificityABSTRACT
Serological findings in a commercial colony of Hartley guineapigs revealed that about 70% had antibodies to Chlamydia psittaci as detected by the microimmunofluorescence method. Conjunctivitis was evident in 14% of 86 guineapigs examined. Chlamydial antigen was detected in conjunctival scrapings by a direct immunofluorescence test using Chlamydia-specific monoclonal antibody; however, C. psittaci was not demonstrated by other methods.
Subject(s)
Chlamydia Infections/veterinary , Conjunctivitis, Inclusion/veterinary , Guinea Pigs/microbiology , Animals , Animals, Laboratory/microbiology , Antibodies, Bacterial/analysis , Chlamydia/immunology , Chlamydia/isolation & purification , Chlamydia Infections/immunology , Chlamydia Infections/pathology , Conjunctivitis, Inclusion/immunology , Conjunctivitis, Inclusion/pathology , Female , Fluorescent Antibody Technique , Male , Rodent Diseases/immunology , Rodent Diseases/microbiology , Rodent Diseases/pathologyABSTRACT
Cervical or urethral scrapings were collected from 245 guinea pigs that had clinical signs of guinea pig inclusion conjunctivitis (GPIC) or were parents of newborn young having clinical signs of GPIC. Giemsa-stained smears were examined for cytoplasmic inclusion bodies, and samples were passaged in 6-day-old embryonating eggs. Complement-fixation tests were performed on 44 samples passaged through eggs in an effort to detect the presence of GPIC antigen. Unequivocal evidence of chlamydial infection of the genital tract was not found.
