| Purpose: Streptococcus agalactiae is one of the main pathogenic bacteria causing invasive diseases in pregnant women and newborns.In recent years,studies have shown that the infection rate of agalactiae has increased in the population with weakened immunity or damage;not only for people,but also for the infection of agalactiae to cows and tilapia is one of the main burdens of animal husbandry and aquaculture in China.The resistance of S.agalactiae was mainly found on erythromycin,clindamycin and levofloxacin;no non-susceptible strain to penicillin was isolated.Penicillin is the first-line drug for the treatment of human infection.For those with penicillin allergy,erythromycin,clindamycin and levofloxacin are mainly used clinically.In order to provide clinical guidance for more rational drug use,the study analyzed the drug resistance,serotype and virulence genes of Streptococcus agalactiae from2019-2021.Methods: Collect 186 S.agalactiae isolated from 2019 to 2021,and tested antimicrobial resistance by vitek2-compact instrument and K-B method,detected the distribution of 10 serotypes and 12 virulence factors by PCR,explored the CAMP factor and the resistance mechanism of erythromycin and clindamycin,analyzed the results,explored the correlation between various distributions,and analyzed the epidemiological characteristics of S.agalactiae.Results: Epidemiological characteristics of the collected clinical isolation of Streptococcus agalactiae: The main sources of clinical isolation of Streptococcus agalactiae are reproductive tract cervical secretions and urine specimens,and the main source department is obstetrics and gynecology,accounting for 39.2% of all the isolated departments.The resistance was mainly reflected on erythromycin,clindamycin and levofloxacin,whose resistance rate were 76.9%,66.1% and 49.4% respectively;no nonsusceptible strains of penicillin,vancomycin and linezolid were found in this experiment,and the resistance rate of all three drugs was more than 100%.The positive result of CAMP experimental species is 93.5%,which is one of the important pathogenic mechanisms of Streptococcus agalactiae;the resistance phenotype of erythromycin and clindamycin: the c MLSB phenotype is 102 strains,accounting for54.8%.A total of six serotypes,namely Ia,Ib,V,were detected,with the highest proportion of 28.5%.The test results of virulence genes showed that fbs B,cyl E,cyl E,hyl B were detected in 186 S.agalactiae;virulence genes l BM,cps A,bac,and scp B all had high positive detection rate of> 80%,while the positive detection rate of fbs A,rib,Cps-and bac was low,<70%.By analyzing the relationship between specimen type and the distribution of resistance rate,the results showed that the relationship between resistance rate and year was insignificant.Compared with previous studies,there can be significant regional differences in S.agalactiae.Conclusion: The main sources of S.agalactiae samples in this region are cervical secretions and urine in the reproductive tract,and the main source departments are obstetrics and gynecology.The resistance rate to erythromycin and clindamycin is high.The resistance phenotype is mainly c MLSB,and the distribution of drug resistance mechanism category is consistent with the results reported at home and abroad.The statistical results of levofloxacin resistance were the same as those in China,but the resistance rate was significantly higher than that abroad.Six serotypes were detected: Ia,Ib,,V,and those with the highest proportion,which is consistent with reports at home and abroad.All fbs B,cyl E,cfb,and hyl B were detected in 186 S.agalactiae,the virulence genes l BM,cps A,bac,scp B had high positive detection rates,all> 80%;while the virulence genes fbs A,rib,Cps-,and bac were low,<70%,which showed some regional differences compared with other studies in China. |
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