Analysis of clinical features, antibiotics-resistance of Bordetella pertussis isolates and treatment outcomes in 211 children with pertussis / 中华传染病杂志

ABSTRACT

Objective:To study the drug resistance patterns of Bordetella pertussis in vitro, and to know the clinical characteristics of pediatric pertussis and evaluation the treatment outcomes, which may provide references for experiential diagnosis and treatment of this disease. Methods:Nasopharyngeal swabs of the hospitalized children with suspected pertussis in Children′s Hospital, Zhejiang University School of Medicine in 2017 were collected for culture. And the clinical data of the children were collected. The strains were identified by pertussis-specific antiserum agglutination and finally confirmed by mass spectrometry. The drug sensitivity test was performed using the E-test method. The efficacy of therapy with antibiotic was evaluated after two weeks of treatment. Statistical analysis was performed with Mann-Whitney U test and chi-square test. Results:Of 1 029 children, 211 (20.5%) nasopharyngeal swabs were positive for Bordetella pertussis culture, and the isolation rate of the specimens was highest (31.2%, 45/144) in July. Of the 211 pertussis patients, 105 (49.8%) were male and the age were 3.8 (2.2, 6.9) months, 114 (54.0%) were not vaccinated with pertussis diphtheria tetanus mixed vaccine and 192 (91.0%) were prescribed with previous antibiotics. There were 142 (67.3%) children from families with two or more than two children, and 136 (95.8%) of which were the youngest siblings. One hundred and fifty-nine (75.4%) patients had paroxysmal cough and 61 (28.9%) had whooping. The white blood cell counts were higher than 20×10 9/L in 94 (44.5%) patients, and the lymphocyte counts were higher than 10×10 9/L in 97 (46.0%) of patients. The drug susceptibility results showed that 138 (65.4%) strains were against erythromycin, azithromycin and clindamycin with minimum inhibitory concentration (MIC)>256.000 mg/L. The MIC 90 of the isolates to ampicillin, ceftriaxone, cefoperazone/sulbactam, meropenem and trimethoprim/sulfamethoxazole were 0.190 mg/L, 0.190 mg/L, 0.094 mg/L, 0.094 mg/L and 0.750 mg/L, respectively. All strains had a MIC of <0.016 mg/L for piperacillin/tazobactam. After treatment, symptoms were improved in 195(92.4%) patients when they were discharged from hospital. Seventy-six (57.1%) children whose symptoms did not improve after seven-day treatment with macrolides, were prescribed with other antibiotics or other antibiotic with macrolides in combination. Compared with the patients treated with macrolides, more patients treated with cefoperazone/sulbactam or piperacillin/tazobactam had negative nasopharyngeal culture results after two weeks of therapy (46/48(95.8%) vs 46/57(80.7%)), or on day seven (45/46(97.8%) vs 39/47(83.0%)) and on day 14 (45/45(100.0%) vs 41/47(87.2%)) since discharged. The differences were all statistically significant ( χ2=5.50, 5.86 and 6.15, respectively, P=0.019, 0.015 and 0.013, respectively). Conclusions:The majority of children with pertussis do not have whooping, and the resistant rate of Bordetella pertussis to macrolides is high. Further study is needed to evaluate the feasibility and reasonability of cefoperazone/sulbactam and piperacillin/tazobactam in treating pediatric pertussis caused by macrolides-resistant Bordetella pertussis.