Preliminary Study On Screening And Therapeutic Effect Of Sensitive Drugs Against Chlamydia Abortus

Chlamydia abortus is an important zoonotic pathogen,which will lead to late pregnancy abortion or stillbirth and weak fetus in goats and sheep.It is an important pathogen leading to endemic abortion in sheep.At the same time,Chlamydia abortus will also infect pigs,cattle,chickens and other livestock,poultry and humans.Chlamydia abortus has been reported in many parts of the world and has some impact on the animal husbandry industry everywhere.In the past 30 years,the results of indirect hemagglutination assay(IHA)have found that at least 11 sheep and goats,13 cattle,5 yaks,15 pigs and12 birds have different degrees of chlamydial infection in China.Economic losses of around ￡20 million are also reported due to animal chlamydial infections in the UK annually.Since there is currently no commercial vaccine for animal chlamydiosis,controlled drug therapy for animal chlamydiosis has become the most effective means in clinical practice.However,there are no systematic and relevant drug treatment studies reported for the drug treatment of chlamydiosis in animals.Firstly,the drug sensitivity of multiple antibiotics to Chlamydia abortus was evaluated at the cellular level and assessed the sensitivity of 12 antibiotics on Mc Coy cells using microdilution-Giemsa staining.The study found that tiamulin and tetracycline had the best antibacterial effect,with inhibitory concentration and bactericidal concentration less than 0.015 μg/m L.Secondly,chicken embryos were further used to verify the inhibition of Chlamydia abortus growth test of tiamulin,by inoculating Chlamydia abortus on chicken embryos and adding antibiotics after gradient dilution,the number of chicken embryo deaths was statictics,and the final results showed that tiamulin could also effectively inhibit the growth of Chlamydia abortus in chicken embryos.Thirdly,guinea pigs were infected with Chlamydia abortus by intraperitoneal injection and treated with different doses of tiamulin by intraperitoneal injection,and the results revealed that the bacterial load of Chlamydia abortus decreased at 14 days after inoculation in guinea pigs and remained relatively stable levels within 14 – 21 days in both the treatment and control group.However,the bacterial load in the heart and eyelid of the treatment group was significantly lower than that of the control group,demonstrating that tiamulin has a certain inhibitory effect in guinea pigs.At the same time,the results showed that Chlamydia abortus mainly parasitized in the uterus,intestine,kidney and brain tissue of guinea pigs by immunohistochemical detection.In summary,tiamulin is a special antibiotic for livestock and poultry.It has not been reported before that tiamulin has certain potential for the treatment of Chlamydiosis abortus in animals through cytostatic test,chicken embryo antibacterial test and animal experiments.However,the preliminary therapeutic test for guinea pig infection failed to completely show that tiamulin had a significant inhibitory effect on Chlamydia abortus in various organs,so further test validation is needed before clinical application.