ABSTRACT
The relative value of culture, direct specimen antigen detection tests, i.e., enzyme-linked immunosorbent assay (ELISA) and immunofluorescence (IF) tests in the diagnosis of Chlamydia trachomatis infection was studied in 125 newborns and 121 adults with signs of conjunctivitis. Eye and nasopharyngeal samples were tested by culture using cycloheximide-treated or irradiated McCoy cells, ELISA (i.e., Chlamydiazyme, Abbott) and IF tests (i.e., Chlamyset, Orion and MicroTrak, Syva). Of the neonates, 70 (35 boys and 35 girls) and 54 (33 males and 21 females) of the adults were positive in one or both eyes in one or more tests: 191 (39%) in cultures, 173 (35%) in ELISA and 160 (33%), 176 (36%) in each of the IF tests. Using culture as standard reference, the sensitivities of ELISA and the IF tests were 88%, 81% and 87%, while the corresponding specificities were 99%, 98% and 97%, respectively. The predictive values for a negative test (PVN) were 93%, 89% and 92% and for a positive test (PVP) 98%, 96% and 94%. Of the 124 cases chlamydia-positive in the eyes, 67 (54%), 76 (61%), 64 (52%) and 70 (57%) were positive in nasopharyngeal samples in one or more of culture, ELISA and the two IF tests, respectively. The sensitivities of ELISA and the IF tests in nasopharyngeal samples were 87%, 78% and 81%, while the corresponding specificities were 90%, 93% and 91%, respectively. The predictive values for a negative (PVN) test were 95%, 92% and 93%, and for a positive test (PVP) 76%, 81%, and 77%. Nasopharyngeal swabs were more often positive in cases with 2 or more weeks' duration of symptoms than in those with shorter duration.
Subject(s)
Chlamydia trachomatis/isolation & purification , Conjunctivitis, Inclusion/diagnosis , Adolescent , Adult , Antigens, Bacterial/analysis , Enzyme-Linked Immunosorbent Assay , Fluorescent Antibody Technique , Humans , Infant , Infant, Newborn , Nasopharynx/microbiologyABSTRACT
Saliva collected from adults with no antichlamydial antibodies in their serum or saliva, was tested for its capacity to inhibit the formation of inclusions of Chlamydia trachomatis in McCoy cell cultures. Pooled saliva, diluted in tissue culture medium and sterilized by filtration, was found to reduce the inclusion count by up to about 40%. However, the pretreatment of the chlamydial organisms for 2 hours with diluted saliva caused a 75% decrease in the number of inclusions. The inhibitory activity, which was concentration-dependent, seems to affect the attachment of the chlamydial elementary body to the host cell by acting on both the chlamydiae and the McCoy cells. Saliva did not seem to affect the intracellular development of the chlamydiae. The inhibitory activity was not affected by trypsin treatment, while absorbtion with a gel of a chelating agent caused total loss of the antichlamydial effect. The purpose of our study was to test saliva for its possible antichlamydial activity and to partially characterize the active principle.
Subject(s)
Antibodies, Bacterial/immunology , Chlamydia trachomatis/immunology , Saliva/immunology , Animals , Antibodies, Bacterial/analysis , Antibodies, Bacterial/physiology , Cells, Cultured , Chlamydia Infections/immunology , Chlamydia Infections/pathology , Chlamydia Infections/prevention & control , Chlamydia trachomatis/physiology , Female , Fibroblasts/drug effects , Fibroblasts/microbiology , Fibroblasts/physiology , Humans , Male , Mice , Saliva/analysis , Saliva/physiologyABSTRACT
A blocking reagent (Abbott) was used to test 153 conjunctival and nasopharyngeal samples from children with signs of early trachoma and from neonates and adults with conjunctivitis caused by Chlamydia trachomatis in whom positive results had been obtained on at least one occasion in an enzyme immunoassay (EIA) (Abbott). EIA and cycloheximide-treated McCoy cell cultures of the eye sample were equally often positive in the non-trachoma cases (70 versus 71), the EIA results being confirmed by the blocking reagent test in these cases. The corresponding figures for the nasopharyngeal samples were 31 versus 25. There was full agreement between the results of the EIA and blocking reagent tests, except in two eye samples and one nasopharyngeal sample where the blocking reagent test was negative. Three EIA results were within the equivocal zone around the cutoff point, two of which were positive and one negative in the blocking test.
Subject(s)
Conjunctivitis, Inclusion/diagnosis , Immunoenzyme Techniques , Trachoma/diagnosis , Adolescent , Adult , Binding, Competitive , Child , Chlamydia trachomatis/isolation & purification , Conjunctiva/microbiology , Humans , Infant, Newborn , Nasopharynx/microbiology , Predictive Value of TestsABSTRACT
Tear fluid collected from healthy children and adults, was tested for its capacity to inhibit Chlamydia trachomatis, serotype I, to form inclusions in McCoy cell cultures. Pooled tear fluid added to such cultures reduced the chlamydial inclusion count even at concentrations of 1%. The inhibitory activity was concentration-dependent. The chlamydial inhibitory factor has a molecular weight of less than 10,000 dalton and the principle is heat-stable. The antichlamydial factor seems to affect the attachment of the elementary body (EB) to the host cell surface, while no effect on the intracellular development and reproduction of the chlamydiae could be demonstrated. The activity could not be explained by the presence of antichlamydial antibodies.
