| Chlamydia trachomatis is the most common pathogen of venereal disease in developed countries. It also causes many complications and serious mental stress to the patients. In our country, the incidence of Ct infection is also found an increasing trend year by year, which becomes a pernicious public health problem.The gold standard of the detection of the Ct is cell culture which is not used widely in the clinical work. Besides, the method of cell culture is the foundation of the drug sensitivity test in vitro. Therefore, it is significantly important to improve the positive rate of the culture of the Ct.One of the critical cause of the treatment failure of the Ct is the persistent infection of the Ct.The typical inclusions cannot be detected by the iodine staining method and the amount of the heat shock protein60of the Ct increases in the persistent infection.Objective:1.To investigate the best concentration of polyethylene glycol (PEG) to enhance the growth of the Ct serotype D-UW-5/Cx and E-UW-5/Cx and the effects of PEG on the drug sensitivity, using azithromycin, minocyline, moxifloxacin and doxycycline.2.To investigate the amount of the heat shock protein60of the laboratory and40clinical strains serotype E in different passages and the relationship between the existentce of the inclusions in the first passage and the treatment effects of the patients.Methods:When the D, E laboratory strains were inoculated on the monolayer of McCoy cells, the culture medium including different concentrations of PEG was added for centrifugation. Then the inoculum was removed and the medium containing1ug/ml cycloheximide was added after2hours’ of incubaion at37℃. After48hours the cells were fixed and stained with iodine to calculate the numbers of the which were treated by0.7%PEG were collected to investigate minimal inhibitory concentrations (MICs) of four antimicrobials.31cell culture positive clinical specimens whose serotypes are D and E were inoculated to the McCoy cells and the inclusion bodies of the first generation are counted. After the40serotype E clinical strains are detected by the cell culture, the RT-PCR was used to test the amount of the CHSP60in the first, second and third passage.The40clinical strains were divided into two groups according to the existence of the inclusions detected in the first passages or not. We used chi square test to investigate the relationship of groups with treatment effects of the patients.Results:The best concentration to enhance the growth of the Ct was0.7%, which could increase the number of the inculsion bodies of the Ct by3.44folds and3.56folds for the serotype E and D respectively. The MICs of the E and D laboratory strains of the four antimicrobials with or without PEG were the same. The0.7%PEG could significantly enhance the growth of the inclusion bodies of the chlamydia trachomatis serotype D and E.The amount of the CHSP60in the strains whose inclusions were not detected in the first passage was higher than the the other passages whose inclusions were detected (P<0.05).Whether the inclusions could be detected in the first passages were correlated with the treatment effects of the patients. The inclusions did not appear in the first passage in the80%patients with treatment failures.The inclusions appeared in the first passages in the70%patients whose chlamydia trachomatis were detected negative after one course treatment.Conclusions:1. The0.7%PEG could enhance the growth of the Ct and it could improve the sensitivity of the detection of Ct in the clinical species.2. This study indicated that the amount of the CSHP60of the chlamydia trachomatis of the patients whose inclusions could not be detected in the first or second passage is higher than the passages when the inclusion bodies were detected by iodine staining.T he Ct may be in a persistent status, the emergence of the inclusions may symbol the remove of the status. |
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