Trend of Antibiotic Susceptibility of Haemophilus influenzae Isolated from Children, 2014–2019

ABSTRACT

Purpose@#We investigated the trend of antibiotic susceptibility of Haemophilus influenzae over 5 consecutive years. @*Methods@#We analyzed the antibiotic susceptibility of H. influenzae isolated from children aged <18 years, who were admitted to the Asan Medical Center Children's Hospital from March 2014 to April 2019. Antibiotic susceptibility of H. influenzae was determined by the disk diffusion test according to the European Committee on Antimicrobial Susceptibility Testing guidelines. @*Results@#Excluding duplicates, 69 isolates were obtained over the past 5 years. The median age of the patients was 5 years (range, 2.8–8.6 years). The antibiotic susceptibility patterns were as follows ampicillin (AMP)-susceptible/amoxicillin-clavulanate (AMC)-susceptible (AS/ACS; n=15 [21.7%]), AMP-resistant/AMC-susceptible (AR/ACS; n=21 [30.4%]), and AMP-resistant/ AMC-resistant (AR/ACR; n=33 [47.8%]). The prevalence of isolates with AR/ACR phenotype tended to increase from 42.1% in 2014–2015 to 54.5% in 2018–2019 (P=0.342). Compared to 2014–2015, the resistance rates to cefuroxime and ceftriaxone in 2018–2019 increased from 31.6% to 77.3% and from 0.0% to 59.1%, respectively (P=0.003 and P<0.001, respectively). @*Conclusions@#Over the last 5 years, H. influenzae isolates with AR/ACR phenotype and ceftriaxone resistance were frequently observed at our institute. The incidence of resistance to cefuroxime and ceftriaxone has increased significantly.