| Objectives : To investigate the pathogen detection and clinical characteristics of suspected children with pertussis in our hospital,and to observe the antimicrobial susceptibility and erythromycin-resistant genes of B.pertussis,provide a scientific evidence for the diagnosis and treatment of pertussis in the region.Methods:From November 2017 to October 2018,the children who were suspected pertussis patients in the Hunan Provincial People's Hospital were studied.Their nasopharyngeal swabs were tested by bacterial culture and PCR.The susceptibility to erythromycin,clindamycin,ampicillin,levofloxacin and sulfamethoxazole-trimethoprim(SMZ-TMP)were test by E-test with positive strains,The susceptibility to erythromycin was also tested with the KB disk diffusion method.The 23 S rRNA gene of positive strains was amplified and sequenced,statistical analysis was performed in conjunction with clinical data.Results:1.From November 2017 to October 2018,a total of 351 nasopharyngeal swab specimens were collected from children with suspected pertussis.All of them were cultured and PCR tested.The positive rate of bacterial culture was 16.8%(59/351),and the positive rate of PCR was 62.4%(219/351).Two cases were positive for bacterial culture and negative for PCR.The number of confirmed cases of pertussis was 221 cases.Among them,males were 58.4%(129/221)and females were 41.6%(92/221);The disease could be seen throughout the year,accounting for 20.4%(45/221)in August.The youngest age is 1 month,the maximum is 7 years old,50.7%(112/221)less than 6 months,78.7%(174/221)less than 1 year,and the majority of infants less than 3 years account for 94.1%(208/221).50.2%(111/221)of children with whooping cough had a family history of cough;50.7%(112/221)had pertussis vaccination.82.4%(182/221)of the specimens were collected before the specimens were used.Among them,macrolides accounted for 18.7%(34/182)and cephalosporins accounted for 36.8%(67/182).34.6%(63/182),9.9%(18/182)medications are not known.2.The most common clinical manifestations of 221 children with whooping cough were 90.5%(200/221)for Paroxysmal cough and 33.5%(74/221)for inspiratory whoop.In the pertussis group,The lymphocyte ratio was higher than that of the non-pertussis group;infants that less than 6 months often had episodes of cyanosis and apnea,fever was often seen in ?6 months;the non-immunization group often had episodes of cyanosis than vaccination group,and the above differences were statistically significant(P < 0.05).There was no significant difference in the incidence of clinical symptoms such as Paroxysmal cough,inspiratory whoop,apnea and positive detection rate of bacterial culture before using specimens(P> 0.05).3.170 cases of 221 children with whooping cough improved blood routine,white blood cell count ?10×109/L accounted for 70%(119/170),lymphocyte ratio was higher than 60% accounted for 80.6%(157/170),167 cases improved chest imaging,which indicated that 68.9%(115/167)of pneumonia,and 149 cases of pertussis in hospital with 45.6%(68/149)of other pathogen infections,combined with respiratory syncytial virus,followed by bacteria infection.4.149 children with pertussis were hospitalized.The minimum hospital stay was 3 days,the longest was 56 days,and the average hospital stay was 8.6 days.149 patients were treated with aerosol and cough after admission.Among them,single atomization treatment was 1.3%(2/149),macrolide antibiotics were 18.8%(28/149),and cephalosporin antibiotics were 8.1%(12/149)and 71.8%(107/149).Antibiotics were used,15 cases were treated with gamma globulin,5 cases were given hormones,and 18 cases were admitted to PICU,14 of which were given ventilator assisted ventilation.97.3%(145/149)had a good prognosis,2%(3/149)had a poor prognosis,and 0.7%(1/148)died.5.The results of E-test showed that all 55 isolates were susceptible to levofloxacin,sulphamethoxazole-trimethoprim and ampicillin.However,51.9%(28/55)of the 55 isolates were susceptible to erythromycin and clindamycin,and the MIC50 and MIC90 were 0.094/>256 and 0.75/>256.All erythromycin-resistant strains had the A2047 G mutation in the 23 SrRNA gene.Conclusion : 1.For children with Paroxysmal cough,infants with episodes of cyanosis or apnea,Leukocytosis and predominant lymphocytosis should be highly alert to the possibility of pertussis,need to be tested for pathogens.2.The pathogen diagnosis of pertussis by fluorescence quantitative PCR method is more sensitive than that of bacterial culture.3.A2047 G mutations of 23 SrRNA gene was found in the strains of pertussis resistant to erythromycin in our center. |
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